摘要:
J. CHFM. SOC. DALTON TRANS. 1992 9993-Diphenylphosphino-(lR)-( +)-camphor DimethylhydrazoneComplexes with Platinum(i1) and Palladium(ii) tSarath D. Perera, Bernard L. Shaw * and Mark Thornton-PettSchool of Chemistry, Leeds University, Leeds LS2 9JT, UKTreatment of the Z-exo-phosphine PPh,C,,H,,NNMe, 1 a with [PdCI,(NCPh),] or Na,[PdCI,,]-4H2Ogives the compound [PdCI,(PPh,C,,H,,NNMe2)] 2a with the PPh, group ex0 and the C=NNMe, con-figuration Z, ie. a six-membered ring chelate complex. The corresponding platinum complex 2d wasmade from l a and [PtCl,(cod)] (cod = cycloocta-1,5-diene). Metathesis of complex 2a or 2d withLiBr, or 2a with Nal, gave the corresponding bromides or iodide. Treatment of 2d with AgNO, gave themononitrato complex [ PtCI(ON0,) (PPh,C,,H,,NNMe,)] 2f.Treatment of [PtMe,(cod)] with l a gave[PtMe,( PPh,C,,H,,NNMe,) J 29. The exo-phosphine l a when treated with acetic acid or hot sodiumethoxide solution was partially converted into a mixture with the corresponding endo-phosphine 1 b.Treatment of [PtCl,(cod)] with the la-1 b mixture gave a mixture of the Z-exo-/endo-chelate complexes[ PtCI,( PPh,C,,H,,NNMe,)]; similar treatment of [ PdCI,( NCPh),] or [ PtMe,(cod)] gave the corres-ponding exo-/endo-complexes. Treatment of 2d with hydrogen chloride gave a new (protonated)species which with ethanol gave the exo-/endo-mixture 2d-3a. The palladium complex 2a with hydrogenchloride followed by methanol gave 2a-3b. and another complex formulated as E-exo-[PdCI,(PPh,C,,H,,NNMe,)] 5. Treatment of 2d with an excess of LiMe gave a new speciesformulated as an anion [ PtMe,( PPh,C,,H,,NNMe,)] - 4, which with methanol gave the exo-/endo-mixture 29-3c. Proton, 13C-{lH} and 31P-{1H} NMR data are given and discussed in some detailparticularly regarding the determination of the stereochemistry at C(3) on the camphor residue.Crystals of compound 2a are orthorhombic, space group P2,2,2, with a = 11 65.1 (2), b = 1272.5(2),c = 21 06.1 (5) pm and Z = 4; final R factor 0.0421 for 281 2 observed reflections.The structure showsthat the co-ordinated PPh, group is on the 3-exo position whilst the C=NNMe, moiety is co-ordinated through the NMe, nitrogen giving a six-membered co-ordinated ring. The arrangementaround C=N is Z.I Ic I 1I I II I II I II 1 1In a previous paper' we showed that treatment of (1R)-(+)-camphor (bornan-2-one) dimethylhydrazone with butyllithium,followed by PPh'CI, gave the 3-em-diphenylphosphino-derivative la with the hydrazone in the Z configuration. Wewent on to make some derivatives of Group 6 metal carbonylsin which the co-ordinated PPh, group remained exo but theC=NNMe, group could be either Z (six-membered chelatering) or E (five-membered chelate ring).In a subsequent paper'we showed that the molybdenum tetracarbonyl complex ofeso-3-diphenylphosphino-( 1 R)-camphor dimethylhydrazone[Mo(CO),( PPh2C, ,"Me,)] underwent a facile redox-fission reaction with hydrogen chloride to give a molybdenum(I1)imine complex, [ M O ( C O ) , C ~ ~ ( P P ~ ~ C ~ ~ H , ,NH)], which withsodium tetrahydroborate-carbon monoxide gave [Mo(CO),( P-PhZCI ,H ,NH)] with an em-PPh, group.In the present paperwe describe the chemistry of some palladium and platinumcomplexes with the Z-em-phosphine l a and the Z-endo-phosphine lb. For the convenience of the reader, the variousreactions and compounds formed are summarized in Scheme 1.Microanalytical data for the new compounds are in theExperimental section, IR and P NMR data in Table 1 and 'H-and 'H- I 3 1 P} NMR data in Table 2.I I Ir I 1 -IResults and DiscussionTreatment of the 2-eso-phosphine la with [PdCI,(NCPh),] ort Sirppl'r?ic'n,crr~. rlutu uiuiiuhle: see Instructions for Authors, J. Chem.Soc.. Dullon Truns., 1992, Issue 1, pp. xx--xxv.Table 1 3'P-(1H) NMR data' and IR databComplexlal b2a2b2c2d2e2f f2g3a3b3c5W )1.1- 10.138.736.938.014.712.816.845.210.834.441.0g60.5'J(PtP) v(C=N>C v(M-Cl)d165516551670 330,275168016754055 1675 340,2853944 16754438 1670 34021559 16554026 1665 335,2851665 330,2802169gI620 330,280a Recorded at 36.2 MHz, chemical shifts (6) in ppm relative to 85%H,PO,, solvent CDCl, unless otherwise stated, 'J(PtP) in Hz.Incm-', all IR bands are of medium intensity. KBr disc. Nujol mulls.IR bands due to ONO, group are at 1535s, 1280s and In CH,CI,.995s Cm-'. In C6D6. - Na2[PdCl,]*4H20 gave the chelate complex [PdCI,(P-Ph,C,,H,,NNMe,)] 2a in good yields; details are in theExperimental section.The complex was characterized byelemental analysis (C, H, N and C1) a singlet 3 ' P-( 'H} NMRresonance (Table l), an IR band at 1670 cm-' assigned tov(C=N) and two IR bands at 330 and 275 cm-I (Table 1)assigned to v( Pd-CI), indicative of a cis-PdC1, arrangement.Similar v( Pd-Cl) frequencies have been reported for complexes1000 J. CHEM. SOC. DALTON TRANS. 1992X Yl a PPh2 Hl b H PPh2M X3a Pt CI3b Pd CI3c Pt MeI CIN Me25M X Y2a Pd CI CI2b Pd Br Br2c Pd I I2d Pt CI CI26 Pt Br Br29 Pt Me Me2f Pt CI ON024-2a+3b (iii) - l a + l b(iii)2 b d 2 a - l a( i i )2g + 3~ 2a + 3b + 5Scheme 1 (i) Acetic acid or NaOEt; (ii) [PtCl,(cod)]; (iii)[PdCl,(NCPh),]; (iu) [PtMe,(cod)]; ( u ) LiBr; (ui) AgNO,; (uii) dryHCl followed by EtOH; (uiii) LiMe; (ix) MeOH; (x) dry HCl followedby MeOH; (xi) NaIof the type cis-[PdCl,(NR,),], cis-[PdCl,(py),] (py = pyri-dine) and cis-[PdCI,(PR,),] (R = H or a l k ~ l ) ., . ~ The 'H NMRspectrum of 2a showed that the NMe, methyl groups are non-equivalent (Table 2). We have determined the crystal structureof this complex (Fig. l), see below for details; in particular thePPh, group is shown to be exo and the NMe, group is co-ordinated in a six-membered chelate ring, i.e. the configurationaround C=N is 2. Treatment of the dichloro-complex 2a withLiBr or NaI in acetone gave the corresponding dibromo- 2b anddiiodo-2c complexes. These were fully characterized.We have also made the dichloro platinum complex 2d bytreating the ligand l a with [PtCl,(cod)] (cod = cycloocta-1,5-diene). It showed a singlet 31P-{ 'H} NMR resonance, withsatellites due to coupling with lg5Pt ['J(PtP) = 4055 Hz], andIR bands at 1675 [v(C=N)] and 340,285 cm-' [v(Pt-Cl)].Theproton NMR spectrum showed that both NMe, methyls arecoupled to lg5Pt (Table 2) and that C(3)-H is also coupled to195Pt and to ,'P. The coupling constants of Ig5Pt to the twoNMe, methyls of 30.1 and 25.8 Hz are typical of a three-bondcoupling and indicate that NMe, is co-ordinated to platinum ina six-membered ring and that the configuration around C=N is2. Treatment of the dichloro-complex 2d with LiBr gave thecorresponding dibromide [PtBr,(PPh,C,,H ,"Me,)] 2e.Since a tertiary phosphine has a greater trans effect and transinfluence than a tertiary amine, we anticipated that it might bepossible to replace chlorine trans to phosphorus in 2d,selectively.When an acetone solution of 2d was treated with 1mole equivalent of silver nitrate the monochloro mononitratocomplex [PtCl(ONO,)(PPh,CloHl ,"Me,)] 2f wasobtained. The 31P-(1H} NMR spectrum showed that it was asingle product with an exceptionally large 195Pt-3 'P couplingconstant, 'J(PtP) = 4438 Hz (Table 1). It is known that'J(PtP) for phosphorus in truns position to a nitrate ligand islarger than that of its chloride analog~e.~,' The infraredspectrum showed only one band due to platinum-chlorinestretch, at 340 cm-'. There were also strong bands at 1535, 1280and 995 cm-', indicative of an ONO, group.Similar valueshave been reported for nitrato complexes of Ni, Pd and Pt.8 Theproton NMR spectrum showed two NMe, singlets withsatellites, due to 195Pt splitting, at 6 2.94 C3J(PtH) = 33.11 and3.40 C3J(PtH) = 21.2 Hz]; these data confirmed that theplatinum was co-ordinated by the NMe, group, i.e. theconfiguration around the C=N bond was 2. Treatment of thedichloride complex 2d with 2 mol of AgNO, did not remove thesecond chloride.We also made the dimethylplatinum complex 2g by heating[PtMe,(cod)] with the exo-phosphine l a in benzene at 60 "Cfor 16 h.We have examined the isomerization of the exo-phosphine l ato the endo-phosphine l b by ,'P-{ 'H} NMR spectroscopy. It isknown that deprotonation of (1 R)-( + )-camphor, followed bytreatment with methyl iodide, gives a mixture (-4: 1) of exo-and endo-( 1 R)-( + )-3-methylcamphor which, when treated withacid or base, is catalytically converted into a mixture of the exoand endo isomers in the proportion of - 1 :9.' We have alsoobserved the presence of both exo and endo isomers ( - 1 : 5 ) of(1 R)-( +)-3-diphenylphosphinocamphor on storage for 16 h of asolution containing lithiated (1R)-( +)-camphor and 1 equiva-lent of PPh,Cl."We have now treated the exo-phosphine l a in tetrahydro-furan (thf) with acetic acid and found partial conversion intolb.After 2 h the proportion of l a to l b was approximately 1 : 1.9and did not change further with time, or on heating the solutionto ca. 60 "C for 4 h. A similar ratio of l a to l b uiz.1 : 1.9 wasobtained by heating to cu. 80 "C a solution of l a in propan-2-01containing acetic acid for 3-4 h. We have also found that theisomerization of l a to l b could be catalysed by sodium ethoxidein ethanol. It was very slow at room temperature but, afterheating l a in 0.4 mol dm-, sodium ethoxide-ethanol-tetrahydrofuran solution at ca. 75 "C for 20 h, the proportion ofl a and l b in the mixture was z 1: 1.5. We were not able toisolate a pure sample of the endo isomer lb. The proportions ofl a and l b in the solid mixture varied between z 1 : 1 andz 1 : 1.5.Since the pure endo isomer l b was not prepared it had to becharacterized as a mixture with la. Microanalytical data (C, Hand N) were in agreement with a formula of C24H31N2P for themixture, i.e.the two components are isomers (see ExperimentaJ. CHEM. SOC. DALTON TRANS. 1992 1 0 0 1Table 2 Proton NMR data"Compound Camphor methyls NMe, C3H C4Hla 0.73(s), 1.05(s), 1.07(s) 1.89 (6 H, s) 3.14 [d, 'J(PH) 1.73 1.61 [t, ,J(HH) = ,J(PH) 4.lIblb 0.85(s), 0.91(s), 1.02(s) 1.81 (6 H, s, br) 3.76 [m, ,J(PH) 1.81 b,c d2a -0.24(~), 0.73(~), 0.92(~) 3.01 (s), 3.66 (s) 2.71 [d, 'J(PH) 14.83 2.47 [dd, 3J(HH) 3.2, ,J(PH) 6.332b -0.24(~), 0.74(~), 0.93(~) 3.07 (s), 3.76 (s) 2.57 [d, ,J(PH) 14.53 2.49 [dd, 3J(HH) 3.2, ,J(PH) 6.112c -0.23(~), 0.73(~), 0.92(~) 3.09 (s), 3.83 (s) 2.51 [d, 'J(PH) 14.01 2.49 [dd, 3J(HH) 3.2, 3J(PH) 6.232d -O.ll(~), 0.74(~), 0.91(~) 3.12 [s, 3J(PtH) 30.11 2.70 [d, ,J(PH) 16.11' 2.48 [dd, 3J(HH) 3.2, ,J(PH) 6.512e -0.17(~), 0.74(~), 0.90(~) 3.23 [s, 3J(PtH) 30.11 2.69 [d, 'J(PH) 16.11' 2.49 [dd, ,J(HH) 3.2, 3J(PH) 6.613.76 [s, 3J(PtH) 25.813.89 [s, 3J(PtH) 26.833.40 [s, 3J(PtH) 21.213.33 [s, ,J(PtH) 16.233.84 [s, 3J(PtH) 23.612f 0.03(s), 0.74(s), 0.94(s) 2.94 [s, 3J(PtH) 33.11 2.43 [d, 'J(PH) 15.91 2.47 [m, ,J(HH) 3.532g 0.06(s), 0.44(s), 0.96(s) 2.32 [s, 3J(PtH) 15.91 2.16 [d, ,J(PH) 15.11 d3a 0.75(s), 0.92(s), l.OO(s) 3.30 [s, 'J(PtH) 28.01 d 2.17 (m, br)3b 0.76(s), 0.81(s), 1.02(s) 3.12 (s), 3.70 (s) 3.03 (m) 2.13 (m, br)3cJ 0.37(s), 0.57(s), 0.95(s) 2.59 [s, 'J(PtH) 16.11 d d5 -O.12(~), 0.74(~), 1.21(~) 2.94 (s), 3.06 ( s ) 3.97 [d, 'J(PH) 15.81 2.29 [dd, 3J(HH) 3.0, ,J(PH) 7.333.38 [s, 3J(PtH) 15.61" Recorded at 100 MHz, chemical shifts are in ppm relative to SiMe,, J values in Hz, solvent CDCl, unless otherwise stated. s = Singlet, m =multiplet, t = triplet, br = broad.Obtained by double-resonance experiments at 400 MHz. 3J(HH) = 4.0 and 4J(HH) = 2.3 Hz. Not resolved.' 3J(PtH) = 6.1 Hz. ' ,J(PtH) = 8.9 Hz. Signal obscured by C3H. In C,D6, 6 1.35 [d, 3J(PH) = 7.0, 'J(PtH) = 69.8, PtMe] and 1.37 [d,3J(PH) = 7.5, 'J(PtH) = 83.8 Hz, PtMe]. Signal obscured by NMe, peaks. In C6D6,6 1.25 (PtMe) and 1.26 (PtMe).Fig. 1 An ORTEP drawing5 of the molecular structure of [~dCl,(~Ph,C,,H,5NNMe,)] 2asection). The endo-phosphine lb showed a singlet 'P-('H}NMR resonance at 6 -10.1 (Table 1) and in the protonspectrum the exo-hydrogen on C(3) was coupled to the methinehydrogen C3J(HH) = 4.0 Hz] and to the em-hydrogen onC(5), C4J(HH) = 2.3 Hz], a 'W coupling'.The coupling tophosphorus was resolved by double-resonance experiments at400 MHz C2J(PH) = 1.8 Hz]. In contrast, the endo-hydrogenon C(3) in the exo-phosphine la was only coupled tophosphorus C2J(PH) = 1.7 Hz], as established by 'H and 'H-{"P} NMR experiments. There are several reports in theliterature that the coupling constants 3J(HH) between a 3-endoproton and a 4-bridgehead proton is zero for camphorderivatives such as la: examples of this include (1R)-( +)-3-exo-methyl~amphor,~ (1 R)-( + )-9-bromo-3-exo-methylcamphor,9(1R)-( + )-9,10-dibromo-3-exo-methylcamphor,g norcamphor' 'and Group 6 complexes of camphor phosphines,' s 2 whereas3J(HH) between a 3-exo proton and a 4-bridged proton is about4.0-4.5 Hz.'.' ' In a range of rigid bicyclic compounds, 3J(HH)between endo and bridgehead protons was found to be zero or< 1 Hz.11002 J.CHEM. SOC. DALTON TRANS. 1992Table 3with estimated standard deviations (e.s.d.s) in parenthesesSelected bond lengths (pm) and angles (") for compound 2aCI( I )-Pd-PC1( 2)-Pd-CI( 1 )N( 2)-Pd-C1( 1 )C( 3)-P-PdC( I 3)-P-C( 3)C( 19)-P-C( 3)C( 6)-C( I )-C(2)C( 7)-C( 1 )-C(6)C( 10)-C( 1 )-C(6)C(3)-C(2)-C( 1)N( I )-C(2)-C(3)C(4)-C(3)-PC( 5)-C(4)-C( 3)C(7)-C(4)-C(5)C( 5)-C(6)-C( 1 )C( 8)-C( 7)-C( 1 )C(9)-C(7)-C( 1 )C( 9)-C( 7)-C( 8)N( 1 )-N(2)-PdC( 1 1 )-N(2)-N( I )C( 12)-N(2)-N( 1 )220.5(3)239.6(4)183.6(8)8 I .2(5)56.9( 1 1 )51.8(10)27.9(9)54.5( 10)54.8( 1 1 )5 0 3 11)50.1(10)85.3( 2)89.6(2)172.1(2)l08.6( 3)1 10.8(3)103.5(3)1 04.5( 6)1 02.1 (7)112.8(7)107.2(6)13236)12 1.7(5)1 03.5( 6)101.0(6)104.0(6)110.6(7)1 16.0(7)1 08.7( 6)125.0( 5 )102.0(6)105.7( 6)C1(2)-Pd-PN( 2)-Pd-PN( 2)-Pd-C1( 2)C( 13)-P-PdC( 19)-P-PdC( 19)-P-C( 1 3)C(7)-C( I FC(2)C( 10)-C( 1)-C(2)C( 1 0)-C( 1 )-C( 7)C(2)-C(3)-PC(4)-C(3)-C(2)C(7)-C(4)-C(3)C(4FC(7)-C( I )C(8)-C(7FC(4)C(9FC(7FC(4)N(2)-N( 1)-C(2)C( 1 1 )-N(2)-PdC( 12)-N(2)-PdC( I2)-N(2)-C( 1 1)N( 1)-C(2)-C( 1)C( 6)-C ( 5)-C (4)229.7(4)2 10.8( 7)179.8(5)148.9( 10)154.7(11)15 I .9( 10)158.4(9)147.9(8)149.0( 10)164.4( 1)96.1(2)1 1742)108.2(2)106.8(3)10 1.5(6)116.2(7)1 17.9(7)120.2(6)117.3(5)101.4( 5)103.9(6)103.0(6)1 15.3(6)1 12.4( 7)120.6(6)104.5(5)109.7( 6)109.1(7)I55.9(9)153.0(11)9 1 .O( 2)93.4( 5)We have measured the 13C NMR spectrum of the exo-phosphine la and assigned all the resonances of theC ,H ,"Me, moiety using ' H-' 3C correlation spectroscopyand comparison with the published data for (1R)-(+)-~ a m p h o r .' ~ . ' ~ We have done similar 13C NMR studies on thela-lb mixture and were thus able to assign shifts and couplingconstants for the endo-phosphine 1 b; see Experimental sectionfor data. The subsequent chemistry of this endo-phosphine lbestablished the configuration around the C=N to be 2 (seebelow).We have made some metal complexes of the exo-/endo-phosphine mixture la and lb.Thus, treatment of a ca. 1: 1mixture of these two chelating phosphines with [PtCl,(cod)] indichloromethane gave a mixture of the two cis-dichlorideisomers [ PtCI,( PPh,C ,H ,"Me,)] 2d and 3a. Theelemental analytical data (C, H, N and C1) for the mixture werein agreement with the formulation C2,H3,CI,N2PPtCH,CI2and the 31P-{'H} NMR spectrum of the mixture showed thepresence of the exo-phosphine complex, characterized by asinglet phosphorus resonance, 6(P) 14.7, with satellites'J(PtP) = 4055 Hz (Table 1) and an approximately equalamount of a complex characterized by a singlet phosphorusresonance at 6(P) 10.8, with satellites, 'J(PtP) = 4026 Hz. The'H NMR spectrum of this mixture showed the presence of 2a(data in Table 2) and two singlets with satellites due to the co-ordinated NMe, group of the second species, 6(H) 3.30C3J(PtH) = 28.01 and 3.84 C3J(PtH) = 23.6 Hz].We thereforeformulate this second species as the endo-phosphine complex 3a.A similar treatment of [PdCI,(NCPh),] with a ca. 1 : 1 mixtureof the phosphines la and lb gave a mixture of the two isomericcomplexes 2a and 3b. We have also prepared a mixture of thedimethylplatinum complexes 2g and 3c by treating a mixture ofla and l b with [PtMe,(cod)]. The mixture would not crystallizebut we characterized it by 31P-{'H) and proton NMRspectroscopy (see Tables 1 and 2).When a solution of complex 2d in dry thf was treated with anexcess of methyllithium the resultant solution showed a singlephosphorus-containing species absorbing at 6 12.2 withsatellies, 'J(PtP) = 2208 Hz.When we treated this solutionwith methanol a mixture of the complexes 2g and 3c in ca. 1 : 1proportions, was formed. These were identified by 'P-{ ' H}NMR spectroscopy. We suggest that the intermediateabsorbing at 6 12.2 is the anion 4.Since the complexes of type 2 have a lone pair on the unco-ordinated nitrogen (C=N) we studied the effect of hydrogenchloride on the e.w-phosphine-platinum dichloride complex 2d,in an attempt to protonate this lone pair. In dichloromethanesolution 2d gave a phosphorus resonance, 6(P) 14.7 ['J(PtP)4055 Hz] and when dry hydrogen chloride was bubbledthrough a solution of 2d in dichloromethane it was completelyconverted into another species, characterized by 6(P) 7.9['J(PtP) = 3437 Hz].We suggest this corresponds to aderivative of 2d containing a Me2NNH,C=CPPh2 moiety.Subsequent treatment of this solution with ethanol gave amixture of 2d and 3a in the approximate proportions of 1 : 3, asshown by 31P-{1H} and 'H NMR spectroscopy. A similartreatment of the palladium complex 2a with dry hydrogenchloride gave a new species, characterized by a singletphosphorus resonance at 6(P) 30.2, again presumably aprotonated complex; this solution, on addition of methanol,gave a mixture ( ca. 1 :2.4) of the exo- and endo-phosphinecomplexes 2a and 3b (proton and 31P-{ 'H} NMR evidence).When we treated a mixture of 2a and 3b with dry hydrogenchloride the species absorbing at 6(P) 30.2 was reformed.Themother-liquor from this mixture gave a new complex in about30% yield but contaminated with small amounts of 2a and 3b.This new complex was characterized by a singlet phosphorusresonance at 6(P) 60.5. We tentatively suggest that this is due tothe five-membered chelate ring complex 5 and have made asimilar five-membered ring chelate complex which also has 6(P) = 60: 4-tert-butylcyclohexanone N,N-dimethylhydrazone wastreated with lithium diisopropylamide or butyllithium, followedby PPh,CI, and the resultant (isolated) phosphine was treatedwith [PdCI,(NCPh),]. This gave the chelate complex 6 thestructure of which has been established by X-ray crystallo-graphy. This complex had 6(P) at 62.5.15 Complex 5 showeda doublet for C(3)-H in the proton NMR spectrum at 6(H)3.97, ,J(PH) = 15.8 Hz (Table 2).These data are characteristicof C(3)-H being endo and therefore PPh, being in an exoposition.+Crystal Structure of [PdCI,(PPh,C,,H, ,NNMe,)] 2a.-The crystal structure of complex 2a is shown in Fig. 1 andselected bond lengths and angles are shown in Table 3 and atomcoordinates in Table 4. The structure shows that the PPh,group is in the exo position and that the palladium is co-ordinated to the NMe, nitrogen. The arrangement around theC=N bond is 2. The co-ordination around palladium isessentially square planar, the deviations being in part due to therestrictions imposed by the rigid camphor backbone. As wouldbe expected, the Pd-CI bond trans to phosphorus is longer[239.6(4) pm] than that trans to nitrogen [229.7(4) pm], due tothe higher trans influence of phosphorus over nitrogen.ExperimentalThe general methods and instruments were the same as in otherrecent publications from this laboratory.'Preparations.-[PdCl,(PPh,C, ,"Me,)] 2a.(i) From[PdCl,(NCPh),]. A solution of the exo-phosphine la (1.0 g, 2.6mmol) in dichloromethane (1 5 cm3) was added to a solution of[PdCI,(NCPh),] (1.0 g, 2.6 mmol) in dichloromethane (25cm3). Addition of ethanol (ca. 25 cm3) to the resulting yellowsolution gave the required product 2a as yellow microcrystals.Yield 1.3 g, 90%J . CHEM. SOC. DALTON TRANS. 1992 1003Table 4 Atom coordinates ( x lo4) for compound 2a with e.s.d.s inY- 1607.0(5)- 3024( 1)- 2683(2)27(2)- 2433(7)- 2006(6)- 2624(6)- 3527(6)- 282 1(8)- 2022(8)- 373 l(7)- 4280(8)-4421(10)- 2078( 10)- 1226(6)- 707(6)- 294( 10)303(7)-4438(3)- 5396( 3)- 6474(3)- 6594(3)- 5673(3)- 4559(3)- 3 108(4)- 2238(4)- 2245(4)- 3 122(4)- 3993(4)- 3986(4)Y-4044.8(4) - 2778.6(2)- 2905( 1 )- 5078(2)-5140(2)- 989(7)- 1830(6)- 1701(5)- 840( 5 )188(6)61(6)- 989(6)- 2034(7)- 106(8)- 1075(8)- 2465(5)- 3228(5)- 3072(8)- 2683(9)- 3329(4)- 2701(4)- 3008(4)- 3944(4)- 4573(4)- 4266(4)- 2483(4)- 1853(4)- 1587(4)- 1951(4)-2581(4)- 2846(4)- 2694( 1 )-21 1 l(1)- 2579( I)- 41 8 I(3)- 3751(3)-3121(3)- 3289(3)- 3282(4)- 3864(4)-4027(3)- 4220(4)-4311(5)- 4873(4)- 3939(3)- 3493(3)- 3935(5)- 321 l(6)-2918(2)- 2800(2)-3021(2)- 3359(2)- 3476(2)- 3256(2)- 1873(2)- 1624( 2)- 98 l(2)- 588(2)- 837(2)- 148O(2)(ii) From Na,[PdC14]-4H,0.A warm solution of the exo-phosphine la (0.30 g, 0.80 mmol) in ethanol (12 cm3) was addedto a solution of Na,[PdC14]=4H,0 (0.24 g, 0.75 mmol) inethanol (1 2 cm3). The resulting solution was heated to ca. 80 "Cfor 1 min and then allowed to cool. This gave the product 2a(0.30 g, 73%) (Found: C, 51.45; H, 5.7; C1, 13.0; N, 4.85.C,,H,,CI,N,PPd requires C, 51.85; H, 5.6; C1,12.75; N, 5.05%).[PdBr2(PPh2Cl0H,,NNMe,)] 2b. A solution of the di-chloro-complex 2a (0.15 g, 0.27 mmol) and an excess of lithiumbromide (0.23 g, 2.7 mmol) in acetone (12 cm3) was put aside for24 h.The solution was then evaporated to dryness and theproduct extracted into dichloromethane. Crystallization fromdichloromethane-acetone gave 2b as yellow microcrystals; yield(0.15 g, 85%) (Found: C, 42.3; H, 4.75; N, 3.8. C24H31Br2-N,PPd-0.6CH2CI, requires C, 42.45; H, 4.65; N, 4.0%).[PdI,(PPh,Cl,Hl,NNMe2)] 2c. This was prepared from 2aand isolated in an analogous manner to 2b; yield 79% (Found:C, 39.05; H, 4.25; N, 3.7. C2,H3,12N,PPd requires C, 39.0; H,4.25; N, 3.8%).[PtCI,(PPh,CloHl,NNMe,)] 2d. A solution containing thephosphine la (1 .O g, 2.67 mmol) and [PtCl,(cod)] (1.0 g, 2.67mmol) in dichloromethane (20 cm3) was refluxed for 45 min.The required product was isolated as off-white microcrystals;yield (1.49 g, 86%) (Found: C, 44.5; H, 4.85; CI, 10.9; N, 4.2.C2,H3,C12N2PPt requires C, 44.7; H, 4.85; C1, 11.0; N, 4.35%).[PtBr,(PPh,C,,H,,NNMe,)] 2e.This was prepared andisolated in an analogous manner to complex 2b, in 82% yield(Found: C, 39.0; H, 4.3; N, 3.7. C,,H,,Br,N,PPt requires C,39.3; H, 4.25; N, 3.8%).[PtCI(N03)(PPh2CloH, ,"Me,)] 2f. Silver nitrate (53 mg,0.31 mmol) in the minimum amount of water was added to asolution containing the dichloro complex 2d (0.20 g, 0.3 1 mmol)in acetone (15 cm3). The precipitate of silver chloride wasfiltered off and the filtrate was evaporated to dryness. Theresultant residue was recrystallized from dichloromethane-I I 11 I 1I I II I fI I Iethanol to give the mononitrato complex 2f as whitemicrocrystals; yield (0.16 g, 77%) (Found: C, 42.55; H, 4.6; C1,4.9; N, 6.1.C2,H3,CIN,03PPt requires C, 42.95; H, 4.65; C1,5.2; N, 6.25%).[~tMe2(~Ph,CloHl,NNMe2)] 2g. A solution containing[PtMe,(cod)] (66 mg, 0.20 mmol) and the phosphine la (76 mg,0.20 mmol) in benzene (1.5 cm3) was heated at ca. 60 "C for 15 h.The resulting yellow solution was evaporated to dryness andthen triturated with ethanol to give the required product 2g aswhite microcrystals; yield (35 mg, 29%) (Found: C, 51.7; H, 6.0;N, 4.65. C2,H3,N2PPt requires C, 51.75; H, 6.2; N, 4.65%).IIsomerization of exo-Phosphine la to endo-Phosphine 1 b.-Amixture of the exo-phosphine l a (1.0 g, 2.77 mmol) and aceticacid (1.3 cm3) was refluxed in propan-2-01(15 cm3) for 4 h.The ' P-{ H} NMR spectrum of the mixture showed it to comprise ofla and lb in the ratio of E 1 : 1.9 (see Discussion). The solventwas removed under reduced pressure and the residue re-crystallized from ethanol to give a white crystalline solid (0.77 g,77%). It was found to be a mixture of l a and lb in the ratio ca.1: 1.5 (see Discussion) (Found: C, 76.3; H, 8.1; N, 7.6.C24H3 'N,P requires C, 76.15; H, 8.25; N, 7.4%). exo-Phosphinela: 13C-{'H} NMR (CDCl,, 100.6 MHz) 6 11.5 (s, C'O), 19.4 (s,C'), 21.9 [d, 4J(PC) 21.1, C9], 30.4 (s, C5), 32.1 (s, C6), 45.7 (s,NMe2), 45.8 [d, 'J(PC) 27.8, C3], 47.1 [d, ,J(PC) 1.6, C'], ,48.0[d, ,J(PC) 1.8, C4], 53.1 [d, ,J(PC) 3.2, C'] and 184.1 [d,'J(PC) 6.7 Hz, C']. endo-Phosphine l b 13C-(1H} NMR(CDCI,, 100.6 MHz) 6 12.5 (s,C'O), 18.4(s,C8), 19.5 (s,C9), 23.0[d, ,J(PC) 15.7, C5], 33.2 (s, C6), 41.9 [d, 'J(PC) 18.8, C3], 45.7(s, NMe,), 48.2 [d, 3J(PC) 1.9, C'], 48.6 (s, C"), 53.7 [d, 3J(PC)1.7, C'] and 183.5 [d, ,J(PC) 9.0 Hz, C2].Reactions between u Mixture (1 : 1) of Phosphines la and 1b.-With [PtCl,(cod)].The complex [PtCl,(cod)] (59 mg, 0.16mmol) was added to a solution containing a mixture (z 1 : 1) ofphosphines la and lb (61 mg, 0.16 mmol) in dichloromethane(ca. 2 cm3). After 2 h the solution was concentrated to a lowvolume under reduced pressure. Addition of methanol gave amixture (E 1: 1) of complexes 2d and 3a as a pale yellowcrystalline solid; yield (71 mg, 69%) (Found: C, 41.1; H, 4.6; C1,19.1; N, 3.7. C2,H,,Cl2N2PPt-CH,CI2 requires C, 41.15; H,4.55; CI, 19.45; N, 3.85%).With [PdCl,(NCPh),]. Similarly, treatment of a mixture( ~ 1 : l ) of phosphines la and l b with [PdCI,(NCPh),] (1equivalent) in dichloromethane gave a mixture (Z 1 : 1) ofcomplexes 2a and 3b in 59% yield (Found: C, 47.95; H, 5.45; N,4.45.C24H3 ,C12N2PPd-0.75CH,C1, requires C, 48.0; H, 5.3; N,4.5%).With [PtMe,(cod)]. A solution containing [PtMe,(cod)] (50mg, 0.15 mmol) and a mixture (Z 1 : 1) of phosphines la and lb(58 mg, 0.15 mmol) in benzene (ca. 1.5 cm3) was heated to ca.60 "C for 22 h. Since the products failed to crystallize thesolution was evaporated to dryness and redissolved in C6D6 for,lP-{ 'H}, 1H-(31P) and 'H NMR studies.Reaction of Complex 2d with Dry Hydrogen Chloride.-Dryhydrogen chloride was bubbled through a solution containingcomplex 2d (0.31 g, 0.48 mmol) in dichloromethane (10 cm3) for90 s.The ,lP-{ 'H) NMR spectrum of this solution showed onlyone phosphorus-containing species, which gave a singlet at 6 7.9with 19,Pt satellites, 'J(PtP) = 3437 Hz. After 1 h the solutionwas concentrated to a low volume (ca. 2 cm3) under reducedpressure and ethanol (ca. 2 cm3) added. A mixture (z 1 : 3) of theisomeric complexes 2d and 3a crystallized as pale yellowneedles; yield (0.24 g, 77%).Reuction of Complex 2a with Dry Hydrogen Chloride.-Dryhydrogen chloride was bubbled through a solution containingcomplex 2a (0.21 g, 0.37 mmol) in dichloromethane (10 cm3) for2 min. The 31P-(1H} NMR spectrum of this solution showedonly one phosphorus-containing species absorbing at 6 30.21 004 J.CHEM. SOC. DALTON TRANS. 1992After 15 min the solvent was removed under reduced pressureand the residue was crystallized from dichloromethane-methanol to give a mixture ( M 1 : 2.4) of the isomeric complexes2a and 3b as yellow microcrystals; yield (88 mg, 42%). Themother-liquor gave complex 5 as yellow microcrystals yield (72mg, 3473, contaminated with small amounts of complexes 2aand 3b (see Discussion) (Found: C, 51.6; H, 5.55; CI, 12.85; N,4.9. C2,H3,C12N2PPd 5 requires C, 51.85; H, 5.6; C1, 12.75; N,5.05%).Reaction between Methyllithium and Complex 2d.-An excessof LiMe (1.4 mol dm-') in diethyl ether (0.4 cm3) was added to asuspension of complex 2d (60 mg, 0.09 mmol) in dry thf (1.5cm').The 3 1 P-{ 'H} NMR spectrum of the resultant pale yellowsolution after 3 h showed a single phosphorus-containingspecies at 6 12.2 { [J(PtP) = 2208 Hz]. A few drops of methanolwere added to this solution. 31P-{1H} NMR spectroscopyshowed after 1 h the presence of a mixture ( z 1 : 1) of complexes2g and 3c, absorbing at 6 45.0 ['J(PtP) = 21691 and 40.5['.I( Pt P) = 2 177 Hz], respectively.Single-crystal X- Ray Diffraction Analysis of Compound 2a.-All crystallographic measurements were carried out at 290 K ona Nicolet P3/F diffractometer using graphite-monochromatedMo-Ka X-radiation (h = 71.069 pm). The unit-cell parametersand their associated estimated standard deviations wereobtained from a least-squares fit of the setting angles of 25reflections in the range 20 < 28 < 25".Data were collected inthe range 4.0 < 28 < 50.0" over 171.4 h using 01-28 scans withno significant variation in the intensities of three standardreflections. Lorentz and polarization corrections were appliedto the data set together with a post structure-solution empiricalabsorption correction.' 'The structure was determined via standard heavy-atom (forthe Pd atom) and Fourier difference techniques and was refinedby full-matrix least squares using the SHELX programsystem. ' All non-hydrogen atoms were refined with anisotropicthermal parameters except for the carbon and chlorine atomsof two disordered CH2C12 molecules which were refinedisotropically. The phenyl groups were treated as rigid bodieswith idealized hexagonal symmetry (C-C 139.5 pm).Allhydrogen atoms were included in calculated positions (C-H 96pm) and were refined with an overall isotropic thermalparameter. The weighting scheme w = [02(Fo) +0.0008(F0)']-' was used. Refinement of the enantiomericstructure (based on L-camphor) led to significantly highervalues of R and R'.Crystal data. C24H3 ,N2PPd*2CH,C12, M = 725.69 (includesboth solvent molecules), orthorhombic, space group P212121,a = 1165.1(2),b = 1272.5(2),c = 2106.1(5)pm, U =3.1223(10)nm', 2 = 4, D, = 1.54 Mg m-', p = 10.77 cm-', F(OO0) =1472. Crystal dimensions: 0.8 x 0.5 x 0.4 mm.Data collection. Scan speeds 2.0-29.3" min-', o scan widths2.0" + a-doublet splitting, 4.0 < 28 < 50.0°, 3884 data collec-ted, 2812 with I > 2.0o(I) considered observed.Structure refinement.Number of parameters = 307, R =Additional material available from the Cambridge Crystallo-graphic Data Centre comprises H-atom coordinates, thermalparameters and remaining bond lengths and angles.0.0421, R' = 0.0453.AcknowledgementsWe thank Johnson Matthey plc for the generous loan ofplatinum salts, the SERC for a post-doctoral researchfellowship to (S. D. P.) and for other support, and Dr. JonathanD. Vessey for measuring the carbon-13 and other high-fieldNMR spectra.References1 S. D. Perera, B. L. Shaw and M. Thornton-Pett, J. Chem. Soc.,2 S . D. Perera, B. L. Shaw and M. Thornton-Pett, J. Organomet.3 G. E. Coates and C. Parkin, J. Chem. SOC., 1963,421.4 D. M. Adams, J. Chatt, J. Gerratt and A. D. Westland, J. Chem. Soc.,5 ORTEP, C. K. Johnson, ORTEP 11, Report ORNL-3794, revised,6 A. Pidcock, Adv. Chem. Ser., 1982, 196, 1.7 P. S. Pregosin and R. W. Kunz, 31P and 13C NMR of TransitionMetal Phosphine Complexes, eds. P. Diehl, E. Fluck and R. Kosfeld,Springer, Berlin, Heidelberg, New York, 1979, p. 94.8 B. M. Gatehouse, S. E. Livingstone and R. S. Nyholm, J. Chem. Soc.,1957,4222.9 J. H. Hutchinson and T. Money, Can. J. Chem., 1984,62, 1899.Dalton Trans., 1991, 1183.Chem., in the press.1964,734.Oak Ridge National Laboratory, TN, 1971.10 S. D. Perera and B. L. Shaw, J. Organornet. Chem., 1991,402, 133.11 J. L. Marshall and S. R. Walter, J. Am. Chem. SOC., 1974,%, 6358.12 A. P. Marchand, Stereochemical Applications of NMR Studies inRigid Bicyclic Systems, VCH, Pearfield Beach, FLA, 1982, p. 112.13 R. Benn, H. Grondey, C. Brevard and A. Pagelot, J. Chem. Soc.,Chem. Commun., 1988,102.14 A. L. Waterhouse, Magn. Reson. Chem., 1989,27,37.15 S . D. Perera, B. L. Shaw and M. Thornton-Pett, unpublished work.16 B. L. Shaw and J. D. Vessey, J. Chem. Soc., Dalton Trans., 1991,3303.17 N. Walker and D. Stuart, Acta Crystallogr., Sect. A, 1984,62, 1899.18 G. M. Sheldrick, SHELX 76, Program System for X-Ray StructureDetermination, University of Cambridge, 1976.Received 2nd September 1991; Paper 1/04566
ISSN:1477-9226
DOI:10.1039/DT9920000999
出版商:RSC
年代:1992
数据来源: RSC