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J. CHEM. SOC. DALTON TRANS. 1988 2555Metallaheteroborane Chemistry. Part 3.t Synthesis of [2,2-( PR,),-I ,2-TePtB,,H,,] (R, = Et,, Bun,, or Me,Ph), their Characterisation by NuclearMagnetic Resonance Spectroscopy, and the Crystal and Molecular Structureof [2,2-( PEt,),-I ,2-TePtBlOH,,] $George Ferguson *Chemistry Department, University of Guelph, Guelph, Ontario, Canada N I G 2 W IJohn D. Kennedy and Xavier L. R. FontaineSchool of Chemistry, University of Leeds, Leeds LS2 9 J TFaridoon and Trevor R. Spalding *Department of Chemistry, University College, Cork, IrelandReaction of [ Pt( PR,),CI,] (R, = Et,, Bun,, or Me,Ph) with the [7-TeBloHll] - anion in refluxingtetrahydrofuran affords the compounds [2,2-(PR3),-1 ,2-TePtB,,Hl0] [R, = Et, ( I ) , Bun, ( 2 ) orMe,Ph (3)] as the major products.An X-ray diffraction study of (I ) (recrystallised from CH,CI,)shows the crystals to be monoclinic, space group Cc with four molecules in a unit cell ofdimensions a = 10.387(2), b = 17.227(4), c = 14.447(3) A, and /3 = 106.83(2)". The final R factorwas 0.020 for 2 601 observed reflections. Principal interatomic distances are Pt-Te 2.704(1), Pt-P2.320(2) and 2.341 (2), Pt-B 2.248(7)-2.295(9), Te-B 2.291 (8)-2.404(8) A. The compounds,together with the [TeB,,H,,] - precursor, have been examined by n.m.r. spectroscopy, and severalinteresting features are noted. Relative sign information for the various nJ(195Pt--1H) couplings tothe heteroborane cluster protons is apparent from two-dimensional [I H-IH] -COSY experiments,and variable-temperature 1H-{31P} spectroscopy on compound (3) reveals AGiZ8 = 62 kJ mol-l forthe rotational metal-to-heteroborane bonding fluxionality.A review of the literature reveals the surprising fact that,whereas twelve-vertex closo metallaboranes are comparativelyrare,' related carbaborane derivatives are well e~tablished.'.~This is particularly noticeable for compounds which containplatinum-borane interactions.Apparently no twelve-vertexdoso-metallaborane containing a single platinum atom is yetknown (although two Pt,Blo species have been characterised).'In platinum carbaborane chemistry several PtC,B, compoundshave been prepared either by reaction of platinum(o) phosphinecomplexes with eleven-vertex C2B9 substrates,, or by reactionof [Pt(cod)CI,] (cod = cyclo-octa-1,5-diene) with [C,B,-H ,I2 -.' Similarly, the reaction of [Pt(trcms-PhCH=CHPh)-(PEt3)J (PhCHXHPh = stilbene) with [NMe,][CB,,H, ,]afforded a PtCB,, product.6 It is interesting to note in an earlyreport that, whereas a variety of reactions could be used toprepare [M(C2B9H, ,),In- complexes (n = &2) of nickel andpalladium, similar reactions failed to produce the platinumanalogue^.^ However, a later paper has reported the solid-statestructure of the commo compound [3,3'-Pt( 1,2-C2B,Hwhich had been prepared from the reaction of 'chloroplatinicacid' in Pr'OH with either K[C,B,H,,] or C,B,H,,.'For twelve-vertex doso complexes with heteroboranes otherthan carbaboranes as ligands, only the compounds [Pt(PEt3)L-(SB ,HI ,)I8 and [2,2-(PPh,),- 1,2-SePtB, ,H ,I9 have beendescribed.The former was prepared from the reaction between[Pt(PEt,),CI,] and [SB,,H,,]2~ and the latter was isolatedfrom the reaction of [Pt(PPh,),] and SeB, ,H, We now reportthe preparation of the first platinatelluraboranes [2,2-(PR,),-1,2-TePtBlOH,,] ( R 3 = Et,, Bun3, or Me,Ph) and theirstructural characterisation by n.m.r. spectroscopy and (for-t Ref. 9 is to be regarded as Part 1; Part 2 is ref. 306.$ ck,.vo-2,2- Ris( t riet hy1phosphine)- 1 -tellura-2-platinadodecaborane-(10).Suppletwntury h t t i uvuiluhl~~: see Instructions for Authors, J . Clieni.Soc., Dultoti T'rmis., 1988, Issue 1, pp. xvii-xx.R = Et) X-ray diffraction techniques. We have also studied therotation of the Pt(PR,), unit above the TeB, face to which it isbonded and have measured the free energy of activation for theprocess using variable-temperature n.m.r.spectroscopy (forR, = Me,Ph).Results and DiscussionThe platinum(r1) complexes [Pt(PR3),C1,] (R, = Et,, Bun,, orMe,Ph) react with [7-TeBl,H,,]- in a 1 : l mol ratio inrefluxing tetrahydrofuran (thf) to give several products. Afterisolation by preparative t.1.c. and recrystallisation fromdichloromethane, the major product in each case showed C andH analyses consistent with the formulation [Pt(PR3)2-TeB,,H,,]. The yields of the air-stable red crystallinecompounds [R, = Et, (l), Bun3 (2), or Me,Ph (3)] were28-49x. The addition of an equimolar quantity of NEt, to thereaction mixture did not appreciably affect the yields.In order to ascertain the solid-state geometry of theplatinatelluraboranes, and because no telluraboranes or theirderivatives had been structurally characterised in the solid statepreviously, it was decided to undertake a single-crystal X-raydiffraction study of (1).Suitable crystals were grown by the slowevaporation of a solution of (1) in dichloromethane. Figure 1presents a perspective view of a molecule of (1) and the cageatomic numbering scheme. Table 1 lists interatomic distancesand selected angles. The gross cage structure is that of adistorted icosahedron with the platinum and tellurium atoms inadjacent positions. The molecule can be regarded as a derivativeof [B,,H,,]2- with the Pt(PEt,), and Te units replacingWadeian BH and BH2- units respectively."The conformation of the P,Pt group with respect to the TeB,face, Figure 2, is the expected one based on the analysis of thehighest occupied molecular orbital (h.o.m.0.)-lowest un-occupied molecular orbital (1.u.m.o.) interactions in ananalogous SB , ,H , compound and is equivalent to that foundin [2,2-(PPh3),-1,2-SePtB,,H,,].9 The angle 8 between ( a ) th2556 J.CHEM. SOC. DALTON TRANS. 1988Table 1. Important molecular dimensions for [2,2-(PEt3),-1,2-TePtB,,H,,I (1)(a) Interatomic distances (A)Pt-TePt-P( 1 )Pt-P(2)Pt-B(3)Pt-B(6)Pt-B(7)Pt-B( 11)Te-B( 3)Te-B(4)Te-B( 5 )Te-B(6)2.704( 1 )2.320(2)2.34 1 (2)2.295(9)2.29 2( 7)2.248(7)2.252(8)2.396(7)2.291 (8)2.3 18(9)2.404(8)C(l1)-C(12) 1.506(11)B(3)-B(4) 1.943( 12)B(3)-B(7) 1.851(12)B(3)-B(8) 1.747(11)B(4)-B(5) 1.908( 12)B(4)-B(8) 1.749( 12)B(4)-B(9) 1.728( 12)B(5)-B(6) 1.948( 13)B(5)-B(9) 1.747( 12)B( 5)-B( 10) 1.741 ( 13)B(6)-B( 10) 1.755( 11)(h) Interatomic angles (") around Pt, Te, P(1), P(2), and C(1), C(3), C(5), C(7), C(9), and C(11)1.8 19(7)1.832(8)1.83 1 (7)1.8 16(7)1.829(7)1.840(9)1.476( 16)1.508(13)1.506(12)1.512(11)1.51 5( 12)Te-Pt-P( 1) 121.70(5)Te-Pt-P(2) 104.24(5)Te-Pt-B( 3) 56.6(2)Te-P t-B( 6) 56.8(2)Te-Pt-B(7) 94.6(2)Te-Pt-B( 1 1 ) 94.7(2)P( 1)-Pt-P(2) 97.70(6)P( l)-Pt-B(3) 90.8(2)P(1)-Pt-B(6) 176.3(2)P( 1)-Pt-B(7) 94.5(2)P( 1)-Pt-B(l 1) 130.9(2)P(2)-Pt-B(3) 160.4(2)B(3)-Te-B(4)B(3)-Te-B(5)B( 3)-Te-B(6)B(4)-Te-B( 5)B( 4)-Te-B(6)B( 5)-Te-B(6)Pt-P( 1 )-C( 1)Pt-P( 1)-C(3)C(1)-P( 1)-C(3)C( 1)-P( l)-c(5)C( 3)-P( 1)-C( 5 )Pt-P( l)-C(5)48.9(3)83.2(3)81.0(3)48.9(3)82.9(3)48.7(3)116.8(2)113.6(3)116.5(3)103.1 (4)102.7( 3)102.2(3)P(2)-Pt-B(6) 86.0(2)P(2)-Pt-B(7) 147.4(2)P(2)-Pt-B(11) 104.1(2)B(3)-Pt-B(6) 85.6(3)B(3)-Pt-B(7) 48.1(3)B(3)-Pt-B(11) 83.0(3)B(6)-Pt-B(7)B(6)-Pt-B( 1 1) 47.7(3)B(7)-Pt-B(11) 47.1(3)82.4(3)Pt-Te-B(3) 53.1(2)P t -Te-B( 4) 93.1(2)Pt-Te-B( 5 ) 93.0(2)P t-Te-B( 6) 52.9(2)B(6)-B(11) 1.836(10)B(7)-B(11) 1.798(10)B(7)-B(12) 1.751(11)B(8)-B( 12) 1.762( 13)B(9)-B(10) 1.799(14)B(7)-B(8) 1.792( 13)B(8)-B(9) 1.764( 11 jB(9)-B(12) 1.792(14)B(lO)-B(ll) 1.802(13)B(10)-B(12) 1.792(11)B(ll)-B(12) 1.782(13)Pt-P(2)-C( 7)Pt-P(2)-C(9)Pt-P(2)-C( 11)C(7)-P(2)-C(9)C(7)-P(2)-C( 1 1)C(9)-P(2)-C( 1 1)P( 1)-C( 1)-C(2)P( l)-C(3)-c(4)P(2)-C(9)-C( 10)P(2)-C( 1 1)-C( 12)P( l)-C(5)-C(6)P(2)-C(7)-C(8)11 I .3(2)1 13.6(3)12 1.6( 2)103.9(3)102.7(4)101.7(4)1 12.9(6)11 2.6(6)11 7.5(6)115.1(5)1 16.9(6)1 1535)(c) Selected interatomic angles (") around B(3), 8(4), B(5), B(6), B(7), B(9, opposite Pt), B(11), and B(12, opposite Te)Pt-B(3)-Te 70.4(2) B(4)-B(9)-B(5)Pt-B( 3)-B(7) 64.6(4) B(4)-B(9)-B(8)Te-B( 3)-B(4) 62.7(3) B(5)-B(9)-B( 10)Te-B(3)-B(7) 118.1(4) B(8)-B(9)-B( 12)Te-B(4)-B( 3) 68.3 (3) B( 10)-B(9)-B( 12)Te-B(4)-B( 5 ) 66.3(3) Pt-B( 1 1)-B(6)B( 5)-B(4)-B(9) 57.2( 5 ) Pt-B( 11)-B(7)B(6)-B(ll)-B(7)66.6(5)60.1(5)58.8(5)59.4(5)59.9( 5)67.3( 3)66.3(3)110.7(6)Te-B(5)-B(4) 64.8(4) B(7)-B( 12)-B(8) 6 1.3(5)Te-B(5)-B(6) 67.9(4) B(7)-B(l2)-B(ll) 61.2(5)B(4)-B(5)-B(9) 56.2(4) B(8)-B( 12)-B(9) 59.5(5)P t -B( 6)-Te 70.3(2) B(9)-B( 12)-B( 10) 60.2(5)Pt-B(6)-B(11) 65.0(3) B( 10)-B( 12)-B( 1 1) 60.6( 5 )Te-B(6)-B(5) 63.4(4) Pt-B(7)-B(3) 67.3(3)Te-B(6)-B(11) 118.7(4) Pt-B(7)-B(8) 117.2(5)Pt-B(7)-B(11) 66.5(3)B(3)-B(7)-B( 1 1) 1 1 1.2(5)Figure 1.ORTEP plot of [2,2-(PEt,),-1,2-TePtBloHloJ ( I ) with boroncage numbering schemeFigure 2. View of the conformation of the TeB, and P,Pt unitsobserved from the top of the TeB, ringplane containing the Pt and Te atoms and the mid-point of theB(7)-B( 1 1) vector and (b) that containing the P( 1)P(2)Pt atomsis 102.5", Figure 2.The corresponding angles were 100.0" in [2,2-(PPh,),-1,2-SePtB1,H,,] and 104" in the isoelectronic [3,3-(PEt3)2-1,2,3-C2PtB9H1 '1.' 'The unique Pt-Te distance of 2.704( 1) A is somewhat shorterthan expected when compared to the Pt-Se distance of 2.676(1J. CHEM. SOC. DALTON TRANS. 1988 2557A in closo-[2,2-(PPh,),-1,2-SePtB,,Hl,],9 taking into accountthe difference in the published covalent radii of Te and Se (ca.0.020 A).' The Pt-Te distance thus implies a higher bond orderin (1) than in the Pt-Se complex. This increased interaction canbe considered to be partly due to the increased steric demands ofthe Te atom compared to the Se atom when placed in the B,,cage (see below).For comparison the Pt-S distance is 2.43 8,in nido-[2,2-(PEt,),-2-H-1,2-SPtB,H,,] and the covalentradius of S is 1.03 A. In the recently reported non-cageplatinum(I1) complexes [pt( 1,2-Te,C6H,)(PPh3),] l4 and[ Pt(TePh(o-C,H4PPh,))][Pt(SCN),1.2dmf (dmf = dimethyl-formamide) the mean Pt-Te bond lengths were 2.589(1) and2.586( 1) respectively. These values must be consideredrepresentative of a two-centre two-electron bonding interactionand therefore the Pt-Te bonding in (1) is not of this type.Two distinct values for the Pt-B distance are found in (1). Themean distance between platinum and boron atoms, B(3) andB(6), which are also bonded to Te is 2.294(9) A whereas thevalue for the interaction with B(7) and B(11) which are notattached to Te is shorter at 2.250(8) A.A similar effect wasobserved in [2,2-(PPh3),-1,2-SePtB,,H,,] where the corre-sponding distances were 2.305(7) and 2.249(8) 8, respectively.Both values from (1) can be considered typical for Pt-Binteractions and fall within the range reported for numerousplatinaboranes. The Pt-P distances, mean 2.33 1( 10) A, aretypical for such bonds.The Te-B distances in the TeB, face attached to platinum, i.e.Te-B(3) and Te-B(6) are longer [mean 2.400(8) A] than thosefrom Te to B(4) and B(5) [mean 2.305( 14) A].The large variations in B-B distances [from B(5)-B(6)1.948( 13) to B(4)-B(9) 1.728( 12) A] and associated B-B-Bangles [for example the acute M 60" angles in B, triangles whichvary from B(5)-B(6)-B( 10) 55.8(5) to B(5)B(lO)B(6) 67.7(5)"]are typical of borane and heteroborane cage structures althoughthe longest values are at the upper end of the 'typical' range.' Inthe present case, the B-B distances in the TeB(3)B(4)B(5)B(6)section of ( I ) are all notably longer [1.908(12)-1.948(13) A]than the other B-B distances [1.851(12)-1.728(12) A].Similareffects were observed in the related closo Pt-Se comp~und.~These differential effects in bonding to the platinum andtellurium centres, together with the 'shorter' Pt-Te bonddiscussed above may suggest some diversion of bondingelectron density into the Pt-Te linkage at the expense ofpiatinum-boron and tellurium-boron bonding.It is interesting to consider further the distortions imposed onthe hypothetical regular icosahedral model compound [B ,-H1,l2- by the introduction of the adjacent platinum andtellurium atoms.The effects may be analysed in terms of theplanarity of the TeB(3)B(7)B(ll)B(6) and B(4)B(8)B( 12)-B(lO)B(5) rings, and the bonding of the B(9) atom to the aboveB, ring. In the TeB, ring the four boron atoms are essentiallycoplanar with no atom more than f0.02 8, above or below theB, plane. However, the tellurium atom lies 0.147 A below theplane containing the four B atoms, i.e. towards the platinumatom. In the B, ring the atoms lie above or below the true planebut they are not far from coplanar, the deviations being B(4)-0.01 1, B(8) 0.034, B(12) -0.044, B(10) 0.037, and B(5) -0.0178, respectively.The B, ring is more nearly planar and thedeviations are less than those reported for the equivalent part ofthe [3,3-(PEt,),-1,2,3-C,PtB9Hl ,] molecule.' In (1) the B(9)atom is notably not symmetrically bonded to the B, ring. TwoB-B distances are significantly shorter [B(9)-B(4) 1.728( 12) andB(9)-B(5) 1.747(12) A] than two others [B(9)-B( 10) 1.799(14)and B(9)-B(12) 1.792(14) A] and the fifth distance B(9)-B(8) isof an intermediate length [1.764(11) A], Table 1. In theequivalent part of the [3,3-(PEt,),-1,2,3-C,PtB,H '1 moleculethe bonding was more symmetrical with all B-B distances in therange 1.767(12)-1.801(12) A." The distortions in (1) discussedabove are presumably a function of the incorporation of therelatively large Pt and Te atoms and may be partly associatedwith the 'antipodal' bonding interactions which can occurthrough either the D", P", or S" type orbital combinations (asclassified by Stone).' Other possibly related antipodal effectsare discussed below in relation to the n.m.r.data.Compounds (1)-(3) were characterised by n.m.r. usingsingle- and multiple-resonance techniques. Selected 'H and ' 'BTable3. Observed ["B-"B]- and ['H-'HI-COSY correlations for (l),and relaxation times Tl(' 'B) (ms) for (I), (2), and (3) (CD,Cl, solutions,297 K)(1)fA T , (' ' B) (approx.)[ ' B-' ' B]- [ H-' HI- (-*-,Assignment COSY COSYb (1) (2) (3)12 (8,10)s, (9)w, (7,11)s, (8,10)s, 8.1 3.7 6.67,11 (12)w, (8,lO)w (12)s, (8,10)s, 5.2 2.0 4.2(3,6)w?9 (12)w, (8,lO)w (12)s, ( 4 3 , 5.3 2.5 ca.4'336 (7,l l)w?, 2.1 0.5 1.7(8,10)w?(9)s, (8710)s, 2.2 0.5 1.8 4,5 (8,lO)w8910 (12)s, (4,5)w, (4,5)s, (9)s' 9.2 4.2 7.4(791 1)w (9)w(8,lO)S( 9 ) ~ ~ (7,111~ ( W , (7,l l)s,(3,6)w?Measured with {'H(broad-band noise)} decoupling. s = Stronger,w = weaker, ? = uncertain. ' Very close ' 'B resonances prevent moreexact estimation.Table 2. Proton and boron-11 n.m.r. data for [2,2-(PR,),-1,2-TePtBloHlo] [R, = Et, (l), Bun3 (2), or Me,Ph (3)] (CD,CI, solution at 297 K)6(' ' B)/p.p.m.'*'1(2) (3) + 19.4+9.05 + 10.7h + 9.0 +9.1 + 7.9 + 10.7 + 7.7 + 8.4- 6.8 - 5.2 - 6.5 - 5.5- 14.3 - 12.8 - 14.4 - 14.4-21.2 - 19.4 -21.3 - 20.6(1) + 19.6 +23.1 + 19.6'J("B-'H)/Hzd - (1) (3)153 137138h ca. 127'138h ca. 135'153 ca.138'162 156145 142I6( 'H)/p.p.m.'*/(1) (2) + 5.74 + 5.67 + 4.25 +4.17 + 6.44 + 6.38 + 1.54' + 1.53 + 3.08 + 3.04 + 1.89 + 1.847(3) + 58.3 + 4.30 + 6.48 + 1.62 + 3.04 + 1.97By relative intensities, incidence of satellite structure arising from ' J ( 195Pt-' 'B), and two-dimensional [' 'B-I 'B]- and [ 'H-'HI-COSY experiments.+0.5 p,p.m. To high frequency of BF,-OEt,. f0.05 p.p.m., to high frequency ofSike,. 'H Resonances related to directly bound "B resonances by selective 'H-{ "B} experiments. These data recorded in CD,C,D, solution at373 K. Accidentally coincident peaks thus only approximate values. Almost coincident peaks prevent more accurate estimation. j Doublet splitting,ca. 10 Hz, possibly due to 3J(3'P-'H).f 8 Hz, measured from resolution-enhanced "B spectra2558 J.CHEM. SOC. DALTON TRANS. 19886(1'B)/ p.p.m.+20 +10 0 -1 0 - 200828,lO800 Q, ' . ' " ' " ' I . . . " ' ' . '+ 20 + 10 0 -1 0 - 206 (llB)/p.p.rn.Figure 3. 128-MHz "B n.m.r. spectra for [2,2-(PEt3),-1,2-TePtBl,Hlo] (1) in CD,CI, solution. The top trace is the straight-forward spectrum, and the second trace was recorded with { 'H(broad-band noise)} decoupling. The bottom diagram is a [' 'Bl 'BI-COSY90 plot [also with { 'H(broad-band noise)} decoupling]. Note thepresence of 19'Pt satellites to the "B(7,ll) resonance, 1J(195Pt-1 'Bjcu. 235 Hzchemical shift and coupling constant data for (1)-(3) aresummarised in Table 2 while Table 3 contains details of["B--"B]- and ['H-'HI-COSY data for (l), and longitudinalrelaxation times T,("B) of the boron nuclei in (l)-(3).Asymmetrised ["B-' 'BI-COSY plot for (1) is shown in Figure 3.Additional n.m.r. data relating to 'H, 31P, and 195Pt nuclei arelisted in the Experimental section.Assignments to the relative atomic positions were made onthe basis of [' ' B-' ' B]- ' and [ 'H-'H]-COSY ' correlations aswell as chemical shift, coupling constant, relative intensity, andselective decoupling data. In general we observe similar overallshielding and intensity patterns to those of closo-[2,2-( PPh,),-1,2-SePtBloHlo],9 with the ten "B resonances arranged in a1 : 2 : 1 : 2 : 2 : 2 sequence within a 40 p.p.m. span. This behaviour isalso similar to the previously reported iron and cobalt selena-and tellura-borane compounds [Co(qs-C,H,)(XBl and[M(XBloH10)2]"- (X = Se or Te, M = Fe or C O ) .' ~A number of points arising from the n.m.r. spectroscopicresults are noteworthy. We discuss principally the data fromcompound ( I ) although the comments apply generally. First,although there is an expected parallel between the 6("B) and6('H)(exo) values for the various BH units in the compoundFigure 4. Plot of 6("Bj uersus 6('H) for the directly bound boron andhydrogen atoms of compounds (1) (O), (2) (Oj, and (3) (A). The linedrawn has slope 6("B): 6('Hj of 11 : 1, and intercept 6('H) + 3.75p.p.m.(Figure 4),20 there are two significant deviations from thegeneral trend that merit comment. The first of these concernsthe 'H(3,6) resonance which is some 1.5 p.p.m.above thegeneral trend (ie., Ao + 1.5 p.p.m.). This shielding increase mayperhaps arise from anisotropies associated with the Pt-Telinkage which flanks this position. The second deviation is thatfor the 'H(9) resonance which is some 2 p.p.m. below the generaltrend (it.., Ao -2 p.p.m.). This is the position antipodal to theplatinum atom and in this context it may be noted thatanomalously low proton shieldings for em-terminal protons inpositions antipodal to other third-row transition metals such asW, Os, and Ir have recently been noted in a variety ofmetallaborane systems., 'Another point of interest is the coupling constant informationthat the various experiments reveal. Coupling constants1J('9sPt-"B) to "B(7,ll) and "B(3,6) are apparent, althoughthe latter was only resolved with resolution enhancementtechniques.That to "B(7,ll) of 233 Hz is within normal rangesthough at the lower end; that to "B(3,6) is therefore very low atcu. 125 Hz. Lower inter-boron coupling constants have beennoted in cluster compounds in which the interboron linkageflanks a more electronegative cluster heteroatom (seelater).20,22 Presumably this also applies to the platinum-boronlinkages flanking the tellurium atom, and the low values couldresult from a diversion of electron density towards bonds to theelectronegative tellurium atom at the expense of bonds to theboron atoms adjacent to tellurium. This is not inconsistent withthe observed geometrical variations discussed above.Nearly all the protons in the platinatelluraboranes exhibitobservable couplings to 19'Pt.The exception to this is 'H(3,6)which is related to platinum uiu a J path and therefore expectedto have a smaller coupling constant than those linked by 3Jpaths; note also that the 'H(3,6) protons are bonded to the twoB atoms that flank. the Pt-Te linkage that induces the small1J(195Pt-1 'B) coupling referred to above. An upper limit to themagnitude of 2J('9sPt-'H) based on the 'H linewidths wouldbe 15-20 Hz for this position. The other 2J('95Pt-'H)coupling, to 'H(7,11), is also small at 24 Hz and is resolvableunder the solution conditions we have used only by selective'H-{' 'B) spectroscopy in which the "B(7,ll) resonance and itstwo 195Pt satellites are each irradiated in turn.23 These'H-("B) experiments also give the relative signs oJ. CHEM.SOC. DALTON TRANS. 1988 2559a0Q0I'Et--A1' + ~ ' ; ~ 0 ' " " ; 5 . D - + i , . o ' +i.o ' +2:0 ' +1'.0 0.06('H)/p.p.mFigure 5.400-MHz 'H n.m.r. spectra for [2,2-(PEt3)2-1,2-TePtBloHlo](I) in CD,Cl, solution. The top trace is a 'H-{ "B(broad-band noise))spectrum from which an otherwise equivalent 'H-{ "B(broad-bandnoise, off-resonance)} spectrum has been subtracted. The bottomdiagram is a two-dimensional ['H-'H]-COSY 90 colour plot [alsofrom data recorded with { "B(broad-band noise)} decoupling]. Thetilted lozenge-shapes of some of the observed cross-correlation peaksarise from the absence or presence of correlations between the '"Ptsatellites of the H resonances, and the slope of the tilt (dashed arrows)depends on the relative signs of the two appropriate coupling constantsnJ(195Pt-'H) (see text). A tilt to the right arises from like signs, and atilt to the left from opposite signs.Thecross-correlations (A) arise betweenthe phosphine methyl and the P--methylene protons, the direction oftilt (hatched arrow) illustrating that 3J(31P-C-C-1H) and' J ( 3 1 P-C-' H ) are of mutually opposite sign' J ( 'ysPt-' 'B) and 2J('95Pt-B-'H) at this position, and showthat the couplings have opposite sign, i.e. 2J(195Pt-'H) isnegative on the reasonable assumption that '.I( 195Pt-11B) ispositive.23 2 5 Thecouplings 3J('95Pt-'H) to H(8,lO) and H( 12)of 33 and 56 Hz respectively are within normal ranges.Thelower value for 'H(4,5) of ca. 20 Hz (apparent only fromasymmetric correlations in two-dimensional [ 'H-'HI-COSYexperiments discussed below (Figure 5)) for a geometricallysimilar coupling path is therefore of interest, although again itshould be noted that this coupling path flanks the moreelectronegative Te position. Of interest is the incidence of a195Pt coupling to the antipodal 'H(9) nucleus, formally via a 4Jpath although there may be a substantial amount of interactionthrough the cluster.The H lines are broad because all the proton resonances arecoupled to others, principally via the 3J(1H-B-B-1H)pathways. However these couplings ensure the success of the[ 'H-'HI-COSY experiment,' Table 3. Interproton corre-lations for all the 3J(1H-'H) coupling pairs (except one) wereapparent from the two-dimensional [ 'H-'HI-COSY plotwhich confirms the positional assignments in Table 2 asdiscussed above. The one 3J('H-1H) correlation not observedis that between 'H(3,6) and 'H(4,5), and it may also be noted( b )l .l ' l . l - ~ 1.50 1.40 1.30 1.20 1.10Figure 6. (a) An illustration of one possible conformation of theligands about Pt in a static structure of [2,2-(PMeZPh),-1,2-TePtBloHl0] (3) showing two Me group environments. (6) 400-MHzProton n.m.r. spectra in the Me,PhP region of (3) in CD3C,D, solu-tion at temperatures from 305 to 355 Kthat some of the other correlations involving these positions arequite weak; again it is probably significant that these positionsflank the more electronegative tellurium atom.Of particular interest is the relative sign information on thecouplings nJ(195Pt-1H) that is available from the ['H-'HI-COSY spectrum. As far as the authors are aware this kind ofinformation has not been obtained from a ['H-'HI-COSYspectrum on a boron cluster compound before.Since only one195Pt satellite of a particular 'H resonance line will beassociated with one particular 195Pt spin state, this satellite linewill only correlate with one such satellite line of a second 'Hresonance. If the two couplings J('95Pt-'H) are of the samesign, then correlations will only be observed for the lowfrequency-low frequency and high frequency-high frequencypairs of satellites. If of opposite sign, then only the lowfrequency-high frequency and high frequency-low frequencycorrelations will be observed.This phenomenon, together withthe experimental linewidth, causes the shapes of most of theinterproton cross-correlations on the contour plot to be'lozenge-like' (Figure 5). The tilt of the 'lozenges' with respect t2560 J. CHEM. SOC. DALTON TRANS. 1988a vertical axis then gives the relative signs of the couplingconstants J(' 95Pt-'H). Interestingly the correlation for the'H(4,S) resonance also appears as a tilted lozenge which therebyindicates the presence of a 3J('95Pt-'H) coupling that is notresolved in the 'H-{ "B(broad-band noise)) spectrum. The ' H-{ ' ' B} results described above for the 7,ll position reasonablyestablish the geminai coupling 2J('95Pt-'H) for this position asnegative in sign and thence, via the two-dimensional ['H-'HI-COSY results, all the observable vicinal couplings 3J( lg5Pt--'H)as positive.These signs are in accord with the few establishedpattern^.^"^^^^The values of 6(31P) and 1J('95Pt-31P) are within rangestypical for bis(phosphine)platinaboranes 2o although perhapssomewhat higher than those observed for non-heteroatom-containing species.The ' 'B and 'H chemical shift data for compounds (2) and (3)(Table 2) are very similar to those for (1) discussed above. Forthe ' 'B spectra the principal differences reside in the successiveincrease in "B linewidth in the sequence PEt, d PMe,Ph <PBu", (as the boron relaxation times, Table 3, increase withdecrease in molecular mobility) which increasingly inhibits theresolution of coupling constants across this sequence.Interesting points include a marginal broadening of the centralparts of the P-alkyl x-proton resonances for the threecompounds upon irradiation at 6( "B)(3,6), which suggests aninvolvement of the "B(3,6) spins in the [AX,],-type spinsystems (A = 31P, X = 'H).This has been noted previously inPt( PMe,Ph),-borane derivative^.,^For the dimethylphenylphosphine compound (3), the twomethyl groups in each of the equivalent phosphine ligands arechemically distinct (even with free rotation about the platinum-phosphorus CJ bonds), Figure 6(a). [The same will be true for thex-protons on the P-thy1 and P-butyl groups but the 6('H)differences are not so marked.] With a rotational twist ofthe Pt(PMe,Ph), unit about the pseudo-five-fold axis thechemically distinct sites are interchanged.Figure 6(6) shows the400-MHz 'H n.m.r. spectra for the Me2PhP region ofcompound (3) in CD3C6D5 recorded from 305 to 355 K. Thecoalescence temperature was 328 K. This gave a value of theactivation energy ACS,, of 62 kJ mol-I for the rotational twistprocess of the Pt(PMe,Ph), unit over the TeB, face (allowancebeing made in the calculation for the differential shieldingvariations do/dT in CD,C,D, of the two different Me grouptypes). Although there are no previous AGS values reported forthe rotation of a Pt(PR,), unit in a closo compound there hasbeen a qualitative statement that the barrier to rotation of aPt(PEt,), unit over the C2B3 face of a closo seven-atommetallacarbaborane was less than that over the C2B3 face ofa closo twelve-atom system.26 A theoretical analysis of therotational barriers in the Pt(PH,), analogues using extended-Huckel calculations has been attempted.26h It was concludedthat the complex rotational process could not be taken simplyas a reflection of the differences in the original displacements ofthe platinum atoms over the carbaborane ligand faces as hadbeen previously suggested.26" Rotation of an q4-boundPt(PMe,Ph), unit with respect to a B, face in nido-[Pt(PMe,Ph),B,,H,,] was reported to have an activationenergy of ca. 79 kJ m01-l.~~ Several rhodium and iridiumcarbaborane compounds of the type [{ MH(PR,),}C,R,B,H,],and related ruthenium complexes, have been studied byHawthorne and co-workers2* with (dynamic) 'Hand 31P-(1H}n.m.r.spectroscopy. The activation energies for the rotation ofthe metal-containing unit were in the range 35-<73 kJ mol-'.In order to complete the n.m.r. spectroscopic study oftelluraborane cages presented here, we have measured n.m.r.parameters for the nido-[7-TeB,,H, '1- anion (Table 4,structure and numbering in Figure 7). The "B chemical shiftscorrespond closely to those previously reported. 1 9 3 2 9 They arenow readily assigned in the eleven-vertex nido structure (I) onthe basis of relative intensities and nearest-neighbourconnectivities as established by [' B-' 'BI-COSY n.m.r.spectroscopy, together with the results of 'H-(' 'B(selective)}spectroscopy.A similar analysis of the [7-SeB,,H, '3- ion hasbeen recently rep~rted.~' The resonance at 6("B) - 16.8 p.p.m.is associated with the bridging proton, thus assigning thisresonance to the B(9,lO) position and therefore the resonance at6("B) - 18.5 p.p.m. to the B(2,3) position and those at -34.0and - 12.8 p.p.m. to the B(l) and B(5) positions respectively. Allthe nearest-neighbour connectivities are reflected in observed[ '' B-' ' B]-COSY correlations, although those between "B(2,3)and ' B(8,ll) flanking the more electronegative Te atom arevery weak. This has precedent in carbaborane ~ h e m i s t r y , ~ ' . ~ ~ . ~ 'and also in couplings to platinum in the platinatelluraboranediscussed above.The 'H resonances were traced to their directlyTable 4. Measured n.m.r. parameters for Cs[nido-7-TeBl,Hl '3 in CD,CN solution at 295 KObserved ObservedAssignment a Tl( '' B)/ms ["B-"BI-COSY ['H-'HI-COSY d~'(intensity) 6( "B)/p.p.m.' (approx.) correlations c*d S( 'H)/p.p.m.' 'J("B-'H)/Hz correlationsFrom relative intensities, COSY correlations, and 'H-{ ' 'B(se1ective)) experiments that associated "B(9,lO) with 6'(H) = - 3.99 p.p.m. ' k0.5p.p.m.; to high frequency of BF,*OEt,. s = Stronger, w = weaker, m = intermediate.- +0.05 p.p.m.; 'H resonances assigned to directly bound B atoms by 'H-("B(se1ective)) experiments. J Measured with { "B(broad-band noise))decoupling. All correlations correspond to 3J paths except those indicated (see footnotes k and I).Measured from (resolution enhanced) "Bspectrum. Approximate value due to overlap with S("B) (8,ll). Measured from 'H spectrum. j Bridging position {designated (p) in ['H-'HI-COSY column).Measured with { 'H(broad-band noise)) decoupling.'J('H-'H) coupling path. ' 4J(1H-1H) coupling pathJ. CHEM. SOC. DALTON TRANS. 19880-2561!#?'H(9,10)(bridge) off scale--' IFigure 7. Proposed structure of nido-[7-TeB,,Hlnumbering schemewith the atoniicbound boron atoms by 'H-{ '' B(se1ective)) n.m.r. spectroscopy,and they exhibited the expected general parallel between 6( "B)and 6('H) values (Figure 8) with the bridging proton resonancesome 6 p.p.m. above the general correlation. The results of [' H-' HI-COSY spectroscopy, carried out in the presence of{ B(broad-band)) decoupling,'* confirmed the connectivitiesand assignments deduced from the [' ' B-' ' B]-COSY work.These [ 'H-'HI correlations arise principally from thecouplings ,.I(' H-B-B-'H), although there are also ,J('H-'H)coupling paths for the bridging protons, and there is noapparent incidence of a 4J( 'H-'H) coupling in this compound,between 'H(9,10) (bridge) and 'H(1).It is of interest that the "B n.m.r.shielding pattern of[TeB,,H - differs considerably from those of (1)-(3), andthat there are greater similarities between the shieldings of (1)--(3) and those 29 of the neutrd nido-7-chalcogenaboranesTeB ,,H , and SeB, ,H , (Figure 9). This suggests greatersimilarities in electronic structure within the neutral species, andindicates that the boron-to-platinum bonding vectors in theplatinated species are more similar to those to the bridginghydrogen atoms [at H(8.9) and H(10,l l)] in TeB,,H,,, and notsimilar to those to the bridging H(9,lO) atom in [TeBloHl J-.ExperimentalBoth the platinum complexes [Pt(PR,),CI,] (R, = Et,, Bun,,or Me,Ph) 3 2 and the telluraborane reagents M[7-TeBloHl '1(M = Cs or NHEt,) 1929 were prepared according to literaturemethods.All preparative experiments were carried out under dry,oxygen-free nitrogen or methane.Subsequent manipulationswere carried out in air except for recrystallisations which weredone in an inert atmosphere. Analytical and preparative t.1.c.was carried out using silica gel (Merck, Kieselgel60, PF 254) asFigure 8.Plot of 6("B) uersus 6('H) for directly bound boron andhydrogen atoms of the nido-[TeB,,H, ,I- anion. The line drawn hasslope 6("B):6('H) of 15:1, with intercept 6('H) = ca. +3.13 p.p.m.-io -20 -30 +io +io 06('B)/p.p.m.Figure 9. Stick representations of the l l B chemical shifts and relativeintensities of (a) nido-[7-TeBl,H, 1]-, (b) closo-[2,2-(PEtJ2-l,2-TePtB,,H,,] (l), and (c) nido-7-TeB,,Hl, (from ref. 29). Lines drawnlink equivalent positions in two cages [(-) adjacent ( x ) to the Ptatom, (. - 0 ) metal (p) to the Pt atom, and (- - - -) antipodal to the Ptatom], and it can be seen that the shielding pattern for [TeB,,H, '3- ismarkedly different from that of compound (1); in fact a near-inversionin the ordering of the resonance positions has occurred whereas manybasic elements of the shielding patterns for (1) and TeBloH12 arecommon, the principal differences being at the 7,ll-position adjacent tothe platinum atom, and at the 9-position antipodal to the platinumatomthe stationary phase and a mixture of dichloromethane-cyclohexane [ ( S : 1) or (7:2)] as eluting solvent.Infrared spectrawere recorded as KBr discs on Perkin-Elmer 457 and 682spectrometers.Reaction of cis-[Pt(PEt,),Cl,] with [NHEt,][7-TeBlo-H, '].-A solution of [NHEt,][7-TeBl,Hl (0.347 g, 0.99mmol) in thf (20 cm3) was added to a suspension of cis-[Pt(PEt,),CI,] (0.50 g, 0.99 mmol) in thf (20 cm3). The mixturewas stirred at room temperature for 48 h and then heated atreflux for 5 min.The solution was concentrated under reducedpressure (rotary film evaporator, 25 "C). Preparative t.1.c.(CH,Cl,-cyclohexane, 5 : 1) produced three bands. The majorcomponent was extracted into CH,Cl, and recrystallised asdark red crystals of closo-[2,2-(PEt,),-l,2-TePtBloHlo] (1)(0.237g, 35%)(Found: C, 21.2; H, 5.8; B, 16.1. C,,H,,B,,P,PtTerequires C, 21.3; H, 5.9; B, 16.0%); i.r.: v,,,. 2 950m, 2 925s,2 865m, 2 545vs (BH), 2 525w (BH), 2 515vs (BH), 2 500w (BH),2 475w (BH), 1 725m,br, 1 485w, 1 448m, 1 420m, 1 415w,1 375m, 1 370m, 1 248m, 1070w, 1 050w, 1 035m, 1 030s, 1 OlOs,1 W m , 970w, 935w, 925m, 905w, 878m, 858m, 820m, 758vs2562 J. CHEM. SOC. DALTON TRANS. 1988Table 5. Positional parameters and their estimated standard deviationsAtom X Y L0.0 *- 0.043 07( 5)- 0.067 6(2)0.232 5(2)-0.019 O ( 8 )- 0.080 9( 13)-0.001 8(7)-0.028 8(11)-0.248 7(8)- 0.294 9( 10)0.313 2(6)0.284 7(8)0.318 2(7)0.173 ll(1) 0.0 *0.172 43(3) 0.175 86(3)0.155 43(9) 0.033 6(1)-0.049 l(6) 0.01 5 4(7)0.070 76(9) -0.107 5(1)-0.026 2(4) -0.060 5(5)0.076 2(5) -0.212 l(5)0.153 7(6) -0.262 8(6)0.060 7(4) -0.164 8(5)-0.235 O ( 8 ) - 0.005 3( 5)0.241 6(4) 0.003 9(5)0.139 4(5) 0.161 8(5)0.257 6(4) -0.103 l(6)* The Pt x and z co-ordinates were fixed to define the origin.r0.294 8( 10)0.303 3(7)0.453 6(8)-0.210 O(8)- 0.234 2(8)-0.074 5(10)- 0.180 4(8)-0.291 2(8)-0.217 4(9)- 0.05 1 6(8)-0.028 7(8)- 0.189 5(9)0.052 3(7)4'0.060 8 ( 5 )0.077 2(5)0.077 O(5)0.179 6(4)0.246 l(5)0.305 7(5)0.275 7(4)0.247 O(4)0.269 5(5)0.340 4(5)0.357 9(5)0.302 l(5)0.341 8(4)0.201 l(6)-0.023 4(6)- 0.005 2( 7)0.021 8(6)0.124 l(6)0.175 2(6)0.105 2(5)0.001 2(6)0.088 6(7)0.078 O(6)-0.069 8(6)-0.021 5(6)-0.028 2(6)720vs, 662w, and 620m cm-'.Proton and ' ' B n.m.r. spectra aresummarised in Tables 2 and 3. Additional n.m.r. data: 195Pt(CD,CI,, 298 K) Z 21.378 710 MHz (6 -995 p.p.m. relative to E21.4 MHz); for B(7,11), 1J('95Pt-"B) was (+)233 Hz; andcouplings nJ('95Pt-'H) (Hz) were as follows; H(12), 3J 56;H(7,l l), ,J -24 [sign opposite to 1J('95Pt-"B) established by'H-{' 'B(se1ective)) spectroscopy]; H(9), 4J + 33; H(3,6), no195Pt satellite structure apparent therefore < ca.15; H(4,5), 3J< +20; H(8,10), 3J +36; 6(31P)(CD2C12 solution, 298 K) +8.6p.p.m. with 1J('95Pt-31P) 2 903 Hz.X-Ray Analysis of [(Et,P),PtTeB, ,H (l).-Crystal data.C,,H4,B1,P,PtTe, M = 677.20, monoclinic, a = 10.387(2),A3, Z = 4, D, = 1.82 g cmP3, F(O00) = 1288, h(Mo-K,) =0.71073 A, p(Mo-K,) = 70.1 cm-', space group Cc or C2/cfrom systematic absences (hkl, h + k = 2n + 1; hOl,l = 2n +1). Space group Cc was chosen and confirmed by the analysis.Structure determination. Dark red diamond-shaped crystalswere grown from dichloromethane. A crystal of dimensions0.24 x 0.27 x 0.45 mm was used for data collection. Accuratecell dimensions and crystal orientation matrix were determinedon an Enraf-Nonius CAD-4 diffractometer by a least-squarestreatment of the setting angles of 25 reflections in the range11 < 8 < 15".The intensities of reflections with indices h 0 to13, k 0 to 22, I - 18 to 18 were measured with data collected inthe range 2 < 28 < 54" by the 0-28 scan method; 0 scan width(0.70 + 0.35 tan8) using graphite-monochromatised Mo-K,radiation. The intensities of three reflections measured every 2 hshowed no evidence of crystal decay. A total of 3 036 reflectionswere measured of which 2836 were unique; the 2601 withI > 3a(I) were labelled observed and used in structure solutionand refinement. Data were corrected for Lorentz, polarisationand absorption effects (max. and min. transmission factors0.341 and 0.158). The space group Cc was chosen ongeometrical grounds (with 2 = 4, C2/c would have the requiredsymmetry of the molecule), and confirmed by analysis of thePatterson function and the successful refinement. The co-ordinates of the platinum and tellurium atoms were determinedfrom analysis of the three-dimensional Patterson function andthose of the remaining non-hydrogen atoms were found via theheavy-atom method.Refinement was by full-matrix least-squares calculations, initially with isotropic and then withanisotropic thermal parameters. At an intermediate stage in therefinement, difference maps showed maxima in positionsconsistent with the expected locations of most of the hydrogenatoms; in the final rounds of calculations the hydrogen atomswere positioned on geometrical grounds (C-H 0.95 A, B-H 1.08A) and included (as riding atoms) in the structure factorb = 17.227(4), c = 14.447(3) A, fl = 106.83(2)", U = 2474(2)calculations.The final cycle of refinement included 234 variableparameters, and a correction was refined for extinction(2.4 x lo-'). R = 0.020, R' = 0.027, goodness-of-fit 1.10,M' = l/[02(Fo) + 0.040 (F,)']. Maximum shift/error was lessthan 0.005. The electron density in the final difference map was1.0 e A-3 adjacent to Pt; no chemically significant features.Scattering factors and anomalous dispersion corrections weretaken from International Tables.33 All calculations wereperformed on a PDPl1/73 computer using the SDP-Plus suiteof programs.34 Atomic co-ordinates and details of moleculargeometry are given in Tables 5 and 1 respectively. Figures 1 and2 are views of the molecule prepared using ORTEP IL3'Additional material available from the Cambridge Crystal-lographic Data Centre comprises thermal parameters, H-atomco-ordinates, and remaining bond lengths and angles.Reaction of cis-[Pt(PBu",),Cl,] with Cs[7-TeBl0H, l].-Asolution of Cs[7-TeBl0H,,] (0.142 g, 0.37 mmol) and NEt,(0.0377 g, 0.37 mmol) in thf (20 cm3) was stirred at roomtemperature for 15 min.To this was added a solution of cis-[Pt(PBun3),C1,] (0.250 g, 0.37 mmol) in thf (10 cm3). Thesolution was stirred at room temperature for 7 d and then heatedat reflux for 24 h. After concentration of the solution underreduced pressure (rotary film evaporator, 25 "C), preparativet.1.c.(CH,Cl,~yclohexane, 7 : 2) produced five bands. Themajor component was isolated after recrystallisation fromCH2CI, as dark red crystals of closo-[2,2-(PBun3),-1,2-TePtBl,Hlo] (2) (0.88 g, 28%) (Found: C, 33.8; H, 7.6.C,4H,4BloPtTe requires C, 34.1; H, 7.6%); i.r.: vmaX, 2 955s,2 925s, 2 870m, 2 550s (BH), 2 500s (BH), 2 482w (BH), 1 460m,1420m, 1 380m, 1 345w, 1295w, 1270vw, 1230w, 1210m,1 190w, 1090m, 1050w, 1012m, 1002m, 968, 935w, 915m,902m, 770w, 721m, 460m, 400m, and 390w cm-'. Proton and'B n.m.r. spectra are summarised in Tables 2 and 3. Additionaln.m.r. data (2% in CD,CI,, 297 K): 6('H) (P-butyl) centred at + 1.91, + 1.55, + 1.45 and (1 : 2: 1 triplet at 400 MHz) +0.97p.p.m.; nJ(195Pt-1H) couplings as follows: H(7,l l), ,J ca.- 15Hz; and H(8,10), 3Jca. 25 Hz; 1J[195Pt-"B(7,11)] was ca. 240HZ.Reaction of cis-[Pt(PMe,Ph),Cl,] with Cs[7-TeBl0H '1.-To a solution of cis-[Pt(PMe,Ph),Cl,] (0.182 g, 0.34 mmol) inthf (35 cm3) was added Cs[7-TeBloHl1] (0.127 g, 0.34 mmol).The solution was stirred at room temperature for 24 h and thenheated at reflux for 24 h. After concentration under reducedpressure (rotary film evaporator, 25 "C) the solution wassubjected to preparative t.1.c. (CH,Cl,-cyclohexane, 7 : 2) andgave three bands. The major band was extracted with CH,Cl,.On recrystallisation, dark red crystafs of cfoso-[2,2-(PMe2Ph),J. CHEM. SOC. DALTON TRANS. 1988 2563Table 6. Experimental details for the two-dimensional n.m.r. experi-ments on compound (1)["B-"BI-COSY ['H-'HI-COSYData size ( t 2 , [,)/words 256,64Transform size 512,256t , Sweepwidth 6 410.3(FZr Fi)/words( = 2 x I ,sweepwidth) 'Hz(F2, Fi)/Hz perDigital resolution 25, 25pointRecycling time 's 0.07Mixing pulse, O 45Window sine-bell squaredOther details continuous(unshifted) *{ H(broad-bandnoise))decoupling512, 128512, 2562 958.611.6, 11.61.145sine-bell squared(unshifted) *gated{ B(broad-bandnoise))decoupling* i.~.Centred on the centre point of the acquired free induction decaydata array (line 2) prior to zero filling to give the transform size (line 3).1,2-TePtBi,Hl,] (3) (0.118 g, 49%) were isolated (Found: C,26.2; H, 4.4. C,,H,,B,,P,PtTe requires C, 26.8; H, 4.5%); i.r.:v,,,, 3038w, 2990w, 2900w, 2540vs (BH), 2525vs (BH),2 495vs (BH), 2 472w (BH), 1 %Ow, 1 562w, 1482m, 1470m,1 430s, 1 420m, 1 410m, 1 315w, 1 308w, 1 292m, 1 280s, 1 268vw,1 19Ow, 1 175w, 1 155w, 1 095s, 1 068w, 1 008s, 1 OOOw, 942s,912vs, 905vw, 872w, 862w, 840m, 832vw, 818w, 765w, 745s,738s, 712s, 690s, and 680m cm-'.Proton and "B n.m.r. spectraare summarised in Tables 2 and 3. Additional data were asp.p.m. relative to E 21.4 MHz) and couplings "J(195Pt-'H) (Hz)were as follows: H( 12), 3Jca. 55; H(7,l l), ,Jca. - 15; H(9), 4J ca.25; H(8,10), co. 25; 6(3'P) = -14.5 p.p.m.; 1J(195Pt-31P,2 979 ? 6 Hz; 6('H) (P-methyl) + 1.86 [ N = (LJ + " J )(31P-1H) = 10 Hz; 3J('95Pt-'H) 23 Hz] and + 1.61 [ N = 9.5Hz; 3J('9sPt-1H) 27.5 Hz]; 6('H) (P-aromatic protons) +7.4 1-7.43 and + 7.56-7.62 p.p.m.; selective ' H-{ ' B) usingv[' ' B(3,6)] broadens P-methyl resonances: ' J [ 195Pt- ' ' B( 7.1 1 )] was cu.+ 240 Hz.~ O ~ ~ O W S (CD2C12, 297 K): E (195Pt) 21.381 190 MHz (6 -879Nucleur Mugnetic Resonance Spectroscopy.-N.m.r. spectros-copy was performed at 9.4 T using commercially availableinstrumentation. The techniques of 'H-{' 1B},23,24936-38 I H-f 3 i P ) 3 9 [ ' 1 B-' 1 B]-COSy, ' 7938,40.4' and [ 'H-'H]- I I 'COSY 1x.38.40 n.m.r. spectroscopy as used in this work wereessentially as described el~ewhere.'~~' 8 3 2 3 , 2 4 7 3 6 - 4 1 In the 'H-i ' ' Bj experiments use was made of the technique 24,42 in which.( I ' B(on-resonance)) spectrum in order to remove protonresonances not coupled to the "B nucleus of interest.In the [' ' B-' ' B]-COSY and [' H-'HI-COSY experiments { 'H-(broad-band noise),' and { "B(broad-band noise)) decouplingrespectively were applied continuously, typical experimentalparameters for the COSY work being summarised in Table 6.Other n.m.r. spectroscopy was straightforward, relaxation timesTI ( B) being measured by the n-delay-n/2-acquire inversion-recovery method, and chemical shifts 6 being quoted positive tohigh frequency (low field) of E 100 for 'H, S 40.480730(nominally 85';, H3PO4) for 31P, E 32.083 971 (nominallyBF3-OEt, in CDCl, for l1B),'' and E 21.4 M H z ~ ~ for 195Pt(E being defined as in ref. 44). For the location of the 19'Ptresonances. it succession of 'H-{ ' 95Pt(high power, selective)}experiments using the P-alkyl 'H signals were first of all rapidlya lH-"1 , B(off-resonance)} spectrum was subtracted from a 'H-carried out in order to locate the approximate resonanceposition before acquisition of the final data by direct 195Pt-{ ' H(broad-band noise)} spectroscopy.AcknowledgementsA generous loan of platinum salts from Johnson Matthey plcis gratefully acknowledged.G. F. would like to thank theN.S.E.R.C. Canada for Grants in Aid of Research. X. L. R. F.and J. D. K. would like to thank the S.E.R.C. for facilities andProfessor N. N. Greenwood for his interest in this work.Faridoon would like to thank the Department of Education ofthe Republic of Ireland for a Senior Studentship.References1 J. D. Kennedy, Prog. Inorg. Chem., 1986, 34, 21 1.2 M.P. Garcia, M. Green, F. G. A. Stone, R. G. Somerville, A. J. Welch,C. E. Briant, D. N. Cox, and D. M. P. Mingos, J. Chwz. Soc., DaltonTrans., 1985, 2343 and refs. therein.3 R. E. King, D. C . Busby, and M. F. Hawthorne, J. Orgunornet. Chem.,1985, 279, 103 and refs. therein.4 M. Green, J. L. Spencer, F. G. A. Stone, and A. J. Welch, J. Chem.SOC., Dalton Trans., 1975, 179.5 L. F. Warren and M. F. Hawthorne, J. Am. Chem. Soc., 1970,92,1157.6 W. E. Carroll, M. Green, F. G. A. Stone, and A. J. Welch, J. Chem.SOC., Dalton Trans., 1975, 2263.7 E. A. Chernyshev, L. K. Knyazeva, Z. V. Belyakova, A. V. Kisin, N. I.Kirillova, A. I. Gusev, and N. V. Alekseev, Zh. Obshth. Khim., 1983,53, 1289.8 W. R. Hertler, F. Klanberg, and E. L. Muetterties, Inorg.Chem.,1967, 6, 1696.9 G. Ferguson, M. Parvez, J. A. MacCurtain, 0. Ni Dhubhghaill, T. R.Spalding, and D. Reed, J. Chem. SOC., Dalfon Trans., 1987, 699.10 K. Wade, Adu. Inorg. Chem. Radiochem., 1976, 18, 1.1 1 D. M. P. Mingos, M. I. Forsyth, and A. J. Welch, J. Cheni. SOC.,Dalton Truns., 1978, 1363.12 See, for example, N. N. Greenwood and A. Earnshaw, in 'TheChemistry of the Elements,' Pergamon Press, Oxford, 1984, ch. 6.13 A. R. Kane, L. J. Guggenberger, and E. L. Muetterties, J . Am. Chem.SOC., 1970, 92, 2571.14 D. M. Giolando, T. B. Rauchfuss, and A. L. Rheingold, Inorg. Chem.,1987, 26, 1636.15 H. J. Gysling and H. R. Luss, Orgunomefullics, 1984. 3, 596.16 A. J. Stone, Inorg. Chem., 1981, 20, 563.17 T. L. Venable, W. C. Hutton, and R.N. Grimes, J. Am. C'hem. SOC.,18 X. L. R. Fontaine and J. D. Kennedy, J. Chem. Soc., Chem. ('ommun.,19 J. L. Little,G. D. Friesen, and L. J. Todd, Inorg. Chem., 1977, 16,869.20 See, for example, J. D. Kennedy, in 'Boron,' ch. 8, in 'MultinuclearNMR,' ed. J. Mason, Plenum, London and New York, 1987, pp.221-258 and refs. therein.21 See, for example, I. Macpherson, Ph.D. Thesis, University of Leeds,1987; I. Macpherson, personal communication, 1987.22 R. J. Astheimer and L. G. Sneddon, Inorg. Chem., 1983,22,1928 andrefs. therein.23 J. D. Kennedy and B. Wrackmeyer, J. Mugn. Reson., 1980, 38, 529.24 S. K. Boocock, N. N. Greenwood, M. J. Hails, J. D. Kennedy, and25 J. D. Kennedy and W. McFarlane, unpublished work.26 ( a ) G. K. Barker, M. Green, F. G. A. Stone, and A. J. Welch, J. Chem.Soc., Dalton Trans., 1980, 1186; (b) M. J. Calhorda, D. M. P. Mingos,and A. J. Welch, J. Organomet. Chem., 1982, 228, 309.27 S. K. Boocock, N. N. Greenwood, and J. D. Kennedy. J. Chem. SOC.,Chem. Commun., 1980, 305.28 T. B. Marder, R. T. Baker, J. A. Long, J. A. Doi, and M. F .Hawthorne, J. Am. Chem. SOC., 1981, 103, 2988.29 W. F. Wright, A. R. Garber, and L. J. Todd, J. Magn. Reson., 1978,30, 595.30 (a) D. Reed, G. Ferguson, B. L. Ruhl, 0. Ni Dhubhghaill, and T. R.Spalding, Polyhedron, 1988, 7, 17; (b) G. Ferguson, M. J. Hampden-Smith, 0. N. Dhubhghaill, and T. R. Spalding, ibid., p. 187.1984, 106, 29.1986, 779.W.'S. McDonald, J. Chem. SOC., Dalton Truns., 1981, 14152564 J. CHEM. SOC. DALTON TRANS. 198831 E. W. Corcoran and L. G. Sneddon, J. Am. Chem. SOC., 1985, 107,32 G. B. Kauffman and D. 0. Cowan, Inorg. Synth., 1960, 6, 211.33 ‘International Tables for X-Ray Crystallography,’ Kynoch Press,34 B. Frenz and Associates Inc., College Station Texas 77840 and Enraf-35 C. K. Johnson, ORTEP 11, Report ORNL-5138, Oak Ridge36 N. N. Greenwood, M. J. Hails, J. D. Kennedy, and W. S. McDonald,37 X. L. R. Fontaine and J. D. Kennedy, J. Chem. SOC., Dalton Trans.,38 M. Bown, X. L. R. Fontaine, and J. D. Kennedy, J. Chem. SOC.,7446.Birmingham, 1974, vol. 4.Nonius, Delft, Holland, 1983.National Laboratory, Tennessee, 1976.J. Chem. SOC., Dalton Trans., 1985, 953.1987, 1573.Dalton Trans., 1988, 1467.39 S. K. Boocock, N. N. Greenwood, J. D. Kennedy, W. S. McDonald,and J. Staves, J. Chem. SOC., Dalton Trans., 1981, 2573.40 X. L. R. Fontaine, H. Fowkes, N. N. Greenwood, J. D. Kennedy, andM. Thornton-Pett, J. Chem. SOC., Dalton Trans., 1987, 1431, 2417.41 M. Bown, X. L. R. Fontaine, N. N. Greenwood, J. D. Kennedy, andM. Thornton-Pett, J. Chem. Soc., Dalton Trans., 1987, 1169.42 J. D. Kennedy and J. Staves, Z. Naturforsch., Ted B, 1979, 34, 808.43 R. J. Goodfellow, in ‘Group VIII transition metals,’ ch. 20 in‘Multinuclear N.M.R.,’ ed. J. Mason, Plenum, London, and NewYork, 1987, pp. 521-562.44 W. McFarlane, Proc. R. SOC. London, Ser. A , 1968, 306, 185.Received 25th November 1987; Paper 71209

ISSN:1477-9226    

DOI:10.1039/DT9880002555

出版商:RSC    

年代:1988

数据来源: RSC