J. CHEM. SOC. DALTON TRANS. 1992 236 1New Bidentate Ligands PPh,CH,C( Buf)=NNR, (R = H or Me)and PPh,CH,C( But)=NN=CHPh and their Complexes withGroup 6-Mefal CarbonylstKing Kuok Hii, Sarath D. Perera, Bernard L. Shaw" and Mark Thornton-PettSchool of Chemistry, University of Leeds, Leeds LS2 SJT, UKTreatment of tert-butylmethyl ketone dimethylhydrazone with LiBu, followed by PPh,CI, gave thecrystalline phosphino dimethylhydrazone PPh,CH,C(Bu')=NNMe, 2a having the C=NNMe, group inthe Z configuration. This phosphine with [Mo(CO),(nbd)] (nbd = norbornadiene) gave[ Mo(CO),{PPh,CH,C( Bu')=NNMe,}] 3a, with a six-membered chelate ring; the correspondingtungsten 3b and chromium 3c complexes were made similarly. When phosphine 2a was heated with[Mo(CO),] some 3a was formed together with the isomeric complex [ Mo(CO),{PPh,CH,C( Bu')=N-NMe,}] 4, with a five-membered chelate ring and an E arrangement around C=NNMe,. When 3a washeated in diglyme [MeO(CH,),O(CH,),OMe] to ca.150 "C the phosphino imine complex[ Mo(CO),{PPh,CH,C( Bu')=NH}] 5 was formed. Compound 2a with hydrazine gave the correspondingphosphino hydrazone 2c, containing a C=NNH, moiety, in over 90% yield. The phosphines 2a or 2c,with sulfur, gave the corresponding phosphine sulfides. The phosphine 2c with [M(CO),(nbd)] gave[M(CO),{PPh,CH,C(Bu')=NNH,}] (M = Mo 3d, W 3e or Cr 3f). When 3d was heated in diglyme toca. 150 "C it also gave complex 5. The oxidation of molybdenum(o) complex 3d with bromine gavethe seven-co-ordinate molybdenum(i1) complex [ MoBr,(CO),{PPh,CH,C( Bu')=NNH,}] 6.Compound2c was condensed with benzaldehyde to give the phosphino mixed-azine PPh,CH,C( Bu')=NN=CH Ph7a, which with H,O, formed the phosphine oxide 7b. The phosphine 7a reacted with [M(CO),(nbd)]to give [M(CO),(PPh,CH,C(Bu')=NN=CHPh}] (M = Mo 8a, W 8b or Cr 8c). Complex 8a withbromine gave the seven-co-ordinate molybdenum(l1) complex [ MoBr,(CO),{PPh,CH,C( But)="=CHPh}] 9. Crystals of complex 3a are monoclinic, space group P2Jn with a = 892.3(1), b =1920.1 (3), c = 1493.6(3) pm, fl = 105.67(1)" and Z = 4, R = 0.0250 for 3530 observed reflections.The structure shows that the C=NNMe, group has the Z configuration and that the NMe, group isco-ordinated to molybdenum, giving a six-membered ring.II I II II I tI I 1r 1 11 I IIn previous papers we have described the preparation of exo-3-diphenylphosphino-( 1 R)-( + )-camphor (- bornan-2-one)dimethylhydrazone ' and its complexes with Group 6 metalcarbonyls,'.' and also with Pd" and Pt'1.3 We have alsoreported the synthesis of a new azine diphosphine, (Z,Z)-tert-butyl diphenylphosphinomethyl ketone azine 1, and its abilityto co-ordinate to Group 6 metal carbonyls, either as a bi- or asa tri-dentate ligand.We have now extended this type ofchemistry to phosphino hydrazones, also derived from tert-butylmethyl ketone. Since hydrazones have a very extensivechemistry and can be used as intermediates for the synthesis ofmany types of molecules and frameworks, we anticipate thatthese types of molecules will open up new areas of co-ordination chemistry.Results and Discussionrert-Butyldiphenylphosphinomethyl ketone dimethylhydrazone2a was prepared in ca.80% yield by deprotonating tert-butylmethyl ketone dimethylhydrazone with butyllithium andthen treating the resulting carbanion with chlorodiphenylphosphine. The preparative, microanalytical and massspectral data for this new functionalised phosphine and othernew compounds are in the Experimental section. Infrared and31P-{ 'H), NMR data are in Table 1, and proton NMR data aret Supplemenrury data avuilable: see Instructions for Authors, J. Cham.Soc., Dulron Trans., 1992, Issue 1, pp, xx-xxv.in Table 2. The stereochemistry around the C=N bond of exo-3-diphenylphosphino-( 1 R)-( + )-camphor dimethylhydrazone wasshown to be Z' by X-ray crystallography and the crystalstructure of the azine diphosphine 1 showed it to have the Z,Zconfiguration around the C=N bonds., Therefore we suggestthat the phosphino dimethylhydrazone 2a also has the 2configuration.It was converted into the correspondingphosphine sulfide 2b by the treatment with monoclinic sulfur.First we have investigated this phosphino dimethyl hydrazone2a as a ligand for Group 6 metal carbonyls. Treatment of 2awith [Mo(CO),(nbd)] (nbd = norbornadiene) gave theexpected product [Mo(CO),{PPh2CH2C(Bu')=NNMe2}] 3a,containing a six-membered chelate ring. The structure of 3a wasdetermined by X-ray crystallography and is shown in Fig. 1;the compound was also fully characterised by elementalanalysis and spectroscopy.The 31P-{ 'H) NMR spectrumshowed a singlet at 6(P) 48.0 and the proton NMR spectrumshowed both NMe, methyls to be equivalent. The correspondingtungsten 3b or chromium 3c complexes were obtained as yellowcrystalline solids by displacing norbornadiene from[M(CO),(nbd)] (M = W or Cr) with the phosphinodimethylhydrazone 2a.In our previous work the molybdenum tetracarbonyl com-plex of (Z)-exo-3-diphenylphosphino-( 1 R)-( + )-camphordimethylhydrazone was isomerised to the corresponding Ecomplex, with a five-membered chelate ring, by heating it inboiling diglyme (2,5,8-trioxanonane) or decane. ' Also when(Z)-exo-3-diphenylphosphino-( 1 R)-( + )-camphor dimethyl-hydrazone was heated with molybdenum hexacarbonyl i2362 J.CHEM. SOC. DALTON TRANS. 1992Table 1 Infrared and 31P-(1H) NMR dataIR bands (cm-')Compound v(C=N) v(N-H) v(Cz0) 31P-( 'H} NMR," 6 ,2a 1610m - 9.72b 1620m 37.62c 1640w 3350m, 3330m (br) - 22.62d 1620 (br)w 3320m, 3200w 34.73a 1620w 2025, 1910,1850 48.03b 1625m 2010,1890,1840 43.8 (266)3c 1630m 2010,1890,1840 65.73d 1630w 3355m, 3225w 2020,1910,1850 49.63e 1625w 3330m, 3220w 2020,1900, 1850 42.0 (264)3f 1635w 3340m, 3220w 2010,1895,1845 66.94 1585w 2025,1910,1850 38.25 1600w 3300m 2020,1905,1850 47.86 1625m 2060,1985, 1925 61.8d7a 161 5m - 10.07b 1615m 24.68a 1595w 2010,1900,1850 49.68b 1600w 2015,1890, 1850 42.9 (263)& 1600w 2010,1900,1850 67.19 1595w 2060,1990,1920 55.4a Recorded at 36.2 MHz, chemical shifts (kO.1 ppm) relative to 85% H,PO,, solvent CDCI, unless otherwise stated, 'J(WP)/Hz in parentheses. AsKBr disc.In CH,Cl,, all carbonyl bands are strong. In CD,Cl,.Ph2P 7""N"But A P P h 21AHYphBut xxX7a PPh27b P(O)Ph2R X R M2a Me PPh2 3a Me Mo2b Me P(S)Ph2 3b Me W2~ H PPh2 3c Me Cr3e H W3f H Cr2d H P(S)Ph2 3d H MOH,5 6CHPhI I5HPhN *N y(C0)4 MoB~~(CO),PPh2 But ),,bPh2ButM8a Mo8b W0c Cr9decane the same E complex was formed.' In an attempt toprepare an analogous five-membered chelate ring complex, thedimethylhydrazone 2a was heated with [MO(CO),] in boilingdecane for ca. 15 min. Some decomposition occurred and wewere able to demonstrate the formation of the hoped-forcomplex 4, but it was contaminated with some of the six-membered ring isomer 3a as shown by elemental analysis and bythe IR, mass and proton NMR data (the ratio of 3a: 4 present inthe mixture was 1.7: 1). Attempts to prepare pure samples of 4were unsuccessful; an attempt to prepare it by heating a solutionof the six-membered chelate ring chelate, 3a, in diglyme to ca.150°C for 3 h caused a lot of decomposition and the onlyproduct isolated was the imine complex 5 [6(P) 47.81 as shownby microanalytical, IR, mass and proton NMR data.Separateexperiments (followed by 31P-( 'H} NMR spectroscopy)suggested that complex 4 was present in the reaction mixtureformed by heating 3a in diglyme at 150 "C but we could notisolate it. The 31P-(1H) NMR studies also showed that, when3a was heated in diglyme in the presence of traces of acetic acid,conversion into 5 was somewhat faster, although the yield wasno better.It is known that dimethylhydrazones of aldehydes or ketonescan be converted into hydrazones by heating them withhydrazine., We therefore attempted to convert the phosphinodimethylhydrazone (="Me,) 2a into the correspondingphosphino hydrazone (=NNH,) by such a hydrazine-exchangereaction. On heating 2a with hydrazine in ethanol the exchangewas slow but in the presence of acetic acid as catalyst, it wascomplete in 2 h and the crystalline phosphino hydrazone 2c wasisolated in over 90% yield.This new functionalised phosphinohydrazone was fully characterised. The 31P-{ 'H) NMRspectrum showed a singlet at 6(P) -22.6 and in the infraredspectrum v(N-H) occurred at 3350 and 3330 cm-'.Prolonged(16 h) treatment of azine l 4 with hydrazine hydrate in thepresence of acetic acid also gave the phosphino hydrazone 2cbut the yield was less good. Treatment of 2c with sulfur gave thecorresponding phosphine sulfide hydrazone 2d, which was fullycharacterised.Treatment of phosphino hydrazone 2c with Group 6 metalcarbonyl norbornadiene derivatives [M(CO),(nbd)] (M = Cr,Mo or W) gave the chelate complexes 3d-3f. We formulate theseas six-membered ring chelates by analogy with the chelatesdescribed above but also because in the 'H NMR spectracoupling of 7-8 Hz was found for J(PH). This value is muchmore in keeping with a three- than a four-bond coupling, asit would be if the chelate ring were five-membered and theconfiguration around the C=N were E.We found that the phosphino hydrazone complex ofmolybdenum, 3d, when heated in diglyme at 150 "C for 2-3 h,gave the imino complex 5 together with a lot of decomposition,i.e.the behaviour is similar to that of the correspondingphosphino dimethylhydrazone complex, 3a, which also de-composed to 5 at 150 "C, as described above. The oxidation ofthe tetracarbonylmolybdenum(o) complex 3d with 1 equivalentof bromine gave the tricarbonylmolybdenum(I1) compleJ. CHEM. SOC. DALTON TRANS. 1992 2363Table 2 Proton NMR data' Table 3estimated standard deviations (e.s.d.s) in parenthesesBond lengths (pm) and angles (") for compound 3a withCompd. ~ ( B u ' ) 6(CH,) Others2a 1.12 (s) 3.05 [2 H, d, ,J(PH) 2.91 2.10 (6 H, s, NMe,)2b 1.17 (s) 3.50 [2 H, d, ,J(PH) 13.61 1.90 (6 H, s, NMe,)2c 0.98 ( s ) 3.10 [2 H, d, ,J(PH) 2.21 4.75 (2 H,s, br,NH,)2d 0.82 (s) 3.80 [2 H, d, ,J(PH) 15.01 5.60(2H,s, br,NH,)3a 0.77 (s) 3.18 [2 H, d, ,J(PH) 9.33 3.02 (6 H, s, NMe,)3b 0.78 (s) 3.24 [2 H, d, ,J(PH) 9.71 3.20 (6 H, s, NMe,)3c 0.77 (s) 3.10 [2 H, d, 'J(PH) 9.51 2.90 (6 H, s, NMe,)3d 0.76 (s) 3.10 [2 H, d, ,J(PH) 8.81 5.40 [2 H, d, br,3e 0.77 (s) 3.10 [2 H, d, ,J(PH) 9.81 5.70 [2 H, d, br,3f 0.76 (s) 3.01 [2 H, d, 'J(PH) 9.33 4.90 [2 H, d, br,4 1.42 (s) 3.55 [2 H, d, ,J(PH) 7.81 2.41 (6 H, s, NMe,)5 1.23 (s) 3.34 [2 H, d, 'J(PH) 21.93 9.46 [I H, d, br,6 b 0.64 ( s ) 3.60 [2 H, d, 'J(PH) 14.0) 6.60(2 H, s, br, NH,)7a 1.22 (s) 3.52 [2 H, d, 'J(PH) 3.23 8.04 (1 H, s, N=CH)7b 1.25 (s) 3.90 [2 H, d, ,J(PH) 15.63 8.00 (1 H, s, N=CH)8a 0.91 (s) 2.90 [2 H, d, 'J(PH) 10.01 8.10 [l H,d, 4J(PH)8b 0.92 (s) 3.00 [2 H, d, 'J(PH) 10.2) 8.27 [l H, d, 4J(PH)8c 0.91 (s) 2.84 [2 H, d, 'J(PH) 10.01 8.09 [l H, d, 4J(PH)9 0.79 (s) 3.20 [2 H, d, 'J(PH) 13.01 9.00 [l H, d, 4J(PH)a Recorded at 100 MHz, chemical shifts (kO.01 ppm) relative to SiMe,,solvent CDCl, unless otherwise stated, coupling constants J in Hz;s = singlet.d = doublet and br = broad. In CD,Cl,.3J(PH) 6.8, NH,]3J(PH) 8.0, NH,]3J(PH) 8.3, NH,],J(PH) 5.6, NH]1.5, N S H ]1.7, N=CH]2.0, N=CH]1.0, N=CH]Fig. Istructure of M o( CO), { fiP h , CH ,C( B ul)=Nh Me , 31 3aAn ORTEP* representation of the crystal and molecular[MoBr2(CO),{PPh,CH,C(Bu')=NNH2>] 6; characterisingdata are in the Experimental section or in Tables 1 and 2.Thestrong carbonyl absorptions, v(C-0), at 2060, 1985 and 1925cm-' is in the expected range for a tricarbonyl derivative ofmolybdenum(~~).~*~Attempts were also made to deprotonate the NH2 group incomplex 3d by treatment with lithium bis(trimethylsily1)amidein dry tetrahydrofuran (thf). The resultant solution wasexamined by 31P-{1H} NMR spectroscopy, which showed asinglet at 6(P) 65.4, i.e. 14.6 ppm downfield from the startingmaterial. It is possible that the hoped-for deprotonated productN(2)-Mo( 1)C(7)-Mo(l)C(~)-MO( 1)C( 2 1 )-N(2)N(31-W)C(4 1)-C(4)C(42)-C(41)C(44)-C(41)C(611)-P(6)0(7)-C(7)0(9)-C(9)P(6)-Mo( 1)-N(2)C(7)-Mo( 1)-P(6)C(8)-Mo( 1)-P(6)C(9)-Mo( 1)-N(2)C(9)-Mo( 1)-C(7)C( lO)-Mo( 1)-N(2)C(lO)-Mo(l)-C(7)C( IO)-Mo( 1 )-C(9)C(22)-N(2)-Mo( 1)N(3)-N(2)-Mo( 1)N( 3)-N( 2)-C(22)C( 4 1 )-C(4)-N( 3)C( 5)-C(4)-C(4 1 )C(43 jC(41)-C(4)C( 44)-C( 4 1 )-C (4)P( 6)-C( 5)-C( 4)C(61 l)-P(6)-Mo(l)C( 62 1 )-P( 6)-M O( 1 )C( 62 1 )-P( 6)-C( 6 1 1)O( 8)-C( 8)-M O( 1 )O(lO)-C(lO)-Mo(l)237.0(4)204.7( 5)199.8(5)1 49.8( 4)146.3(4)1 5 3.4( 5 )153.2(6)152.5(6)184.8(3)114.6(4)1 13.9(4)82.9( 1)95.2(2)91.7(2)99.0(2)86.6(2)86.1(2)173,4( 1)87.2(2)1 08.8( 2)1 1 1.0(2)102.5(3)1 15.4(3)117.1(3)108.6(3)1 12.1(3)1 13.2(3)117.7(2)119.9(2)10 1.4(2)178.7(2)176.9(2)P(6)-Mo( 1)C(8)-Mo( 1 )C(4)-N(3 1C(5)-C(4)P(6)-C( 5 )0(8)-C(8)O(l0)-C( 10)C(1O)-Mo(1)C(22)-N( 2)C(43)-C(41)C( 62 1 )-P( 6)C(~)-MO( 1 )-N(2)C(8)-Mo( 1)-N(2)C(~)-MO( 1)-P(6)C(9)-MO( 1)-C(8)C( 10)-Mo( I )-P(6)C( 10)-Mo( 1)-C(8)C(2 l)-N(2)-Mo( 1)C(22)-N(2)-C(21)N(3)-N(2)-C(2 1 )C(4)-N( 3)-N (2)C(5)-C(4)-N(3)C(42)-C(4 1 )-C(4)C(43)-C(4 1 )-C(42)C(44 j C ( 4 1 )-C(42)C( 5)-P( 6)-M O( 1 )C(61 l)-P(6)-C(5)C(621)-P(6)-C(5)O(7 )-C(7)-Mo( 1)0(9)-C(9rM0( 1)C(8)-Mo( l)-C(7)2 50.7(4)195.0(5)204.5(5)149.5(4)1 28.3 (4)15 1.3(5)153.9( 5 )185.7(4)184.3(3)1 16.4(4)114.7(4)92.5(2)174.4( 1)89.6(2)177.3( 1)86.2(2)9 1,1(2)92.4( 2)11 5.2(2)106.2( 3)1 I2.2(3)121.3(3)127.6( 3)109.8(3)109.7( 3)108.2(3)110.7(2)102.7( 2)174.4(2)174.3(2)102.0(2)was formed but attempts to methylate this product, bytreatment with methyl iodide, or to introduce a trimethylsilylgroup, by treatment with trimethylsilyl chloride, were notsuccessful and the only solid product isolated from thesemixtures was the starting material 3d.Since the NH, group of a hydrazone is often very nucleophilicand will condense readily with aldehydes or ketones, we havetreated phosphino hydrazone 2c with benzaldehyde.Conden-sation was rapid and the expected phosphino mixed azine 7awas readily isolated as a pale yellow crystalline solid in 59%yield; it is likely that the orientation around the PPh2CH2C-(Bu')=N-N moiety is 2 and around N-N=CHPh is E.Thisnovel ligand was fully characterised and also converted into thecorresponding phosphine oxide 7b by treatment with hydrogenperoxide.We have studied the mixed azine 7a as a ligand for theGroup 6 metal carbonyls. Treatment of [Mo(CO),(nbd)]or [Mo(CO),] with 7a gave the chelate complex[Mo(CO),{ PPh,CH,C(Bu')=NN=CHPh}] 8a. The corre-sponding tungsten 8b and chromium 8c complexes were madesimilarly. The characterising data for complex 8a-8c are in theExperimental section or in Tables 1 and 2. The observed weakcoupling [J(PH) = 1.5-2.0 Hz] between the olefinic proton(N=CH) and the phosphorus is most likely a four- than a five-bond coupling. Therefore we formulate these complexes as six-membered chelates. We also oxidised the molybdenum complex8c with 1 equivalent of bromine to give the seven-co-ordinatecomplex 9,which was fully characterised. Although the configurationaround the N-N=CHPh double bond in 7a or 7b is probably E,as stated above, the corresponding configuration in thecomplexes of type 8 or 9 is not known.Hydrazones show many kinds of reactions and we anticipatethat the phosphino hydrazones such as 2c could be used asI I II I I[ Mo Br ,( CO) { PP h2CH 2C( Bu')=NN=CH Ph > 2364 J.CHEM. SOC. DALTON TRANS. 1992Table 4 Atom coordinates ( x lo4) for compound 3a with e.s.d.s inY140 1.3(2)3746(2)4962(3)3 3 8 8( 3)43 58( 2)4895(3)5485(3)4531(3)7208(3)5358(3)4999(3)309O.4( 7)2400(2)325 5(2)2734(2)1357(2)502(2)1023(2)3679(2)5 133(2)5484(2)4381(2)2927(2)2576(2)1738(3)18 17(2)-433(3)- 1513(2)- 24( 3)- 940(2)986(3)7 16(2)Y1890.I( 1)1459(1)1999(1)1121(1)879(1)973( 1)315(1)187(2)422(2)165 I (1)2091.5(3)1755( 1)1874( 1)1608( 1)1224( 1)1 105( 1)1371(1)2984( 1)3 138(1)3818(1)4345( 1)4191(1)351 I( 1)2860( 1 )3391(1)2236(1)2441(1)1712(1)1626( 1)886( 1 )319(1)-329(1)7723.1(1)8727( 1)91 1 l(2)9546(2)8297(1)759 l(2)72 13(2)6208(2)7 243 (2)7785(2)7095(2)6652.0(4)5452( 1)4811(1)391 l(1)3652( 1)4293( 1)5193(1)6445( 1)63 14( 1)6112(1)6040( 1 )6171(1)6373( 1 )83 12(2)8661 (2)6799(2)6234( 1)8 525 (2)81)24( 1)7266(2)7039( 1)intermediates for the synthesis of whole new types of ligands,including multidentate ligands, macrocycles, etc., this we areinvestigating.Crystal Structure of[Mo(CO),{ PPh,CH,C(Bu')=NNMe,}]3a.-The crystal structure of compound 3a is shown in Fig.1,selected bond lengths and angles in Table 3, and atomcoordinates in Table 4. The structure shows that the C=NNMe2group is in the Z configuration and that the NMe, nitrogen isco-ordinated to molybdenum, giving a six-membered ring.There is nothing abnormal about the bond lengths and angles.ExperimentalThe apparatus used and general techniques were the same asin other recent papers from this laboratory., tert-Butylmethyl ketone dimethylhydrazone was prepared according to aliterature pr~cedure.~Preparations.-tert-Butyl diphenylphosphinomethyl ketonedimethylhydrazone 2a.A solution of LiBu" in hexane (1.6 moldm-3, 27.0 cm3, 0.042 mol) was added to a solution of tert-butylmethyl ketone dimethylhydrazone (6.0 g, 7.4 cm3, 0.042mol) in dry tetrahydrofuran (90 cm3) at - 15 "C. After 1 h asolution of chlorodiphenylphosphine (7.5 cm3, 0.042 mol) in drytetrahydrofuran (40 cm3) was added with stirring, and thereaction mixture then allowed to warm to room temperature,after which it was evaporated to a low volume under reducedpressure. Addition of methanol to the residue gave the requiredphosphine 2a as white needles, m.p. 85-87 "C. Yield 10.1 g, 81%(Found: C, 73.6; H, 8.5; N, 8.5. C20H,,N,P requires C, 73.6;H, 8.35; N, 8.6%). Mass spectrum (electron impact, EI); m/z 326( M + ) and 269 (M - Bu').Conversion of compound 2a into the corresponding phosphinesuljide 2b.A mixture of the phosphino dimethylhydrazone 2a(0.20 g, 0.61 mmol) and monoclinic sulfur (20 mg, 0.62 mmol)was refluxed in benzene (5 cm3) for 2 h. The sulfide 2b separatedand was isolated as white prisms. Yield 0.20 g, 92% (Found: C,67.45; H, 7.85; N, 7.90. C20H27N2PS requires C, 67.4; H, 7.65;N, 7.85%).tert-Butyl diphenylphosphinomethyl ketone hydrazone 2c.(i) From compound 2a. A mixture of compound 2a (2.0 g, 61.4mmol), an excess of hydrated hydrazine (0.7 cm3) and glacialacetic acid (0.5 cm3) was refluxed in ethanol (7 cm3) for 2 h. Thesolution was evaporated to low volume under reduced pressureand the concentrate was cooled to -30 "C, which gavecompound 2c as white needles, m.p.88-90 "C. Yield 1.78 g, 94%(Found: C, 73.25; H, 7.95; N, 9.65. C,,H,,N,P requires C, 72.45;H, 7.75; N, 9.4%). Mass spectrum (EI): mjz 298 (M'), 282 (A4 -NH,) and 241 (M - Bu').( i i ) From compound 1. A mixture of the azine diphosphine 1(0.65 g, 1.15 mmol), an excess of hydrated hydrazine (1 .O cm3)and acetic acid (1.0 cm3) was refluxed in propan-2-01 for 16 h.The reaction mixture was then concentrated to a small volumeunder reduced pressure, and ethanol (ca. 5 cm3) added. It wasthen cooled to -30 "C, after which the required compound 2cseparated and was isolated as white needles. Yield 0.35 g, 51%.Conversion of compound 2c into the corresponding sulfude 2d.The phosphino hydrazone 2c (0.20 g, 0.67 mmol) and mono-clinic sulfur (22 mg, 0.69 mmol) were refluxed together inbenzene ( 5 cm3) for 1 h.The solution was then evaporated to alow volume under reduced pressure and methanol added to theresidue. This gave the required sulfide 2d as white prisms. Yield112 mg, 51% (Found: C, 65.5; H, 7.15; N, 8.5. C,,H,,N,PSrequires C, 65.5; H, 7.0; N, 8.5%).[Mo(CO),{ PPh,CH,C(Bu')=NNMe,)] 3a. A solution con-taining the phosphino dimethylhydrazone 2a (0.49 g, 1.50mmol) and [Mo(CO),(nbd)] (0.48 g, 1.60 mmol) in benzene (5cm3) was put aside for 15 h. It was then filtered and the filtrateevaporated to a low volume under reduced pressure. Additionof ethanol to the residue gave complex 3a as yellow micro-crystals. Yield 0.62 g, 77% (Found: C, 53.85; H, 5.1; N, 5.25.C,,H,,MoN,O,P requires C, 53.95; H, 5.1; N, 5.25%). Massspectrum (EI): m/z 536 (M'), 508 (M - CO), 480 ( M - 2CO)and 424 (M - 4CO).[W(CO),{ PPh,CH,C(Bu')=NNMe,}] 3b.A solutioncontaining phosphino dimethylhydrazone 2a (0.10 g, 0.3 1mmol) and [W(CO),(nbd)] (0.12 g, 0.30 mmol) was refluxed inbenzene (5 cm3) for 20 h. The reaction mixture was then filteredand the filtrate evaporated to low volume under reducedpressure. Addition of methanol to the residue gave the requiredproduct 3b as yellow microcrystals. Yield 0.125 g, 66% (Found:C, 46.5; H, 4.5; N, 4.55. C2,H2,N20,PW requires C, 46.3; H, 4.4;N, 4.5%). Mass spectrum (EI): m/: 622 (Ad+), 566 (M - 2CO)and 5 10 (M - 4CO).[Cr(CO),(PPh,CH,C(Bu')=NNMe,)] 3c.A solution con-taining phosphino dimethylhydrazone 2a (0.10 g, 0.3 1 mmol)and [Cr(CO),(nbd)] (78 mg, 0.30 mmol) in benzene (4 cm3) wasrefluxed for 24 h. The solution was then evaporated to lowvolume under reduced pressure. Addition of methanol to theresidue gave the required product 3c as yellow microcrystals.Yield 120 mg, 80% (Found: C, 58.7; H, 5.65; N, 5.85.C2,H2,CrN204P requires C, 58.8; H, 5.55; N, 5.7%). Massspectrum (ET): m/z 490 ( M ' ) and 406 (M - 3CO).[Mo(CO),{ PPh,CH,C(Bu')=NNH,}] 3d. A solution of thephosphino hydrazone 2c (0.15 g, 0.5 mmol) and [Mo(CO),-(nbd)] (0.15 g, 0.4 mmol) in benzene (5 cm3) was put aside at cu.20 "C for 1 h. The required complex 3d deposited as yellowprisms, which were filtered off and washed with benzene.Yield0.175 g, 86% (Found: C, 57.0; H, 4.95; N, 4.8. C22H23-MoN,0,P-0.9C6H, requires C, 57.0; H, 4.95; N, 4.85%). Massspectrum (EI): m/z 508 ( M + ) , 480 ( M - CO), 452 ( M - 2CO)and 396 (M - 4CO).[W(CO),(PPh2CH2C(But)=NNH2}] 3e. A solution of thelI I 1I I II J. CHEM. SOC. DALTON TRANS. 1992 2365phosphino hydrazone 2c (65 mg, 0.22 mmol) and [W(CO),-(nbd)] (80 mg, 0.21 mmol) in benzene (2 cm3) was refluxed for24 h. Complex 3e was deposited as yellow microcrystals, whichwere filtered off and washed with cyclohexane. Yield 74 mg, 61%(Found: C, 49.7; H, 4.2; N, 4.15. C22H23N204PW-0.9C6H6requires C, 49.5; H, 4.3; N, 4.2%). Mass spectrum (EI): m/z 594( M + ) , 538 ( M - 2CO) and 482 ( M - 4CO).[Cr(CO),(PPh,CH2C(Bu')=NNH2}] 3f.The phosphinohydrazone 2c (95 mg, 0.32 mmol) and [Cr(CO),(nbd)] (80 mg,0.31 mmol) were refluxed in benzene (2 cm3) for 18 h. Therequired product 3f was deposited as yellow microcrystals,which were filtered off and washed with cold methanol. Yield112 mg, 77% (Found: C, 59.95; H, 5.35; N, 5.35. C,,H,,CrN,-O,P*O.5C6H6 requires C, 59.95; H, 5.25; N, 5.6%). Massspectrum (EI): miz 462 (M'), 447 ( M - NH), 406 ( M - 2CO),378 ( M - 3CO) and 350 (M - 4CO).Reaction of compound 2a with [Mo(CO),]. A mixture of[Mo(CO),] (0.52 g, 2.0 mmol) and the phosphine 2s (0.65 g, 2.0mmol) was gently refluxed in decane (8 cm3) for 15 min. Somedecomposition occurred; the resulting dark solution wasallowed to cool to ca. 20°C. The supernatant liquid wasdecanted from the precipitate, which was then crystallised fromdichloromethane-ethanol to give a mixture (z 1.7 : 1) ofcomplexes 3a and 4.Yield 0.55 g, 51% (Found: C, 54.05; H, 5.1;N, 5.25. C2,H2,MoN20,P requires C, 53.95; H, 5.1; N, 5.25%).Mass spectrum (EI): m/z 536 (Ad+), 508 (M - CO), 480 ( M -2CO) and 424 ( M - 4CO).1 I[Mo(CO),{ PPh,CH,C(Bu')=NH}] 5. A solution containingthe dimethylhydrazone complex 3a (0.48 g, 0.89 mmol) and atrace of acetic acid in diglyme (6 cm3) was heated to ca. 150 "Cfor 30 min and allowed to cool. The solvent was removed underreduced pressure, and the residue extracted into dichloro-methane (5 cm3) which was filtered through Celite. The filtratewas concentrated to a low volume (ca. 0.5 cm3) and methanol(ca.1.5 cm3) added to give the imine complex 5 as yellow prisms.Yield 0.085 g, 19% (Found: C, 53.85; H, 4.55; N, 2.85.C,,H,,MoNO,P requires C, 53.75; H, 4.5; N, 2.85%). Massspectrum (EI): miz 493 (M'), 465 ( M - CO), 437 ( M - 2CO),409 ( M - 3CO) and 381 ( M - 4CO).[MOB~,(CO)~(PP~,CH,C(BU')=NNH~}] 6. A solution ofbromine in carbon tetrachloride 0.533 mol dm-3, 0.38 cm3, 0.2mmol) was added to a solution containing the tetracarbonyl-molybdenum(o) complex 3d (80 mg, 0.15 mmol) in dichloro-methane (1.5 cm3). A vigorous effervescence occurred. Thereaction mixture was evaporated to a low volume underreduced pressure, and methanol added to the residue to give thedibromide 6 as yellow microcrystals. Yield 62 mg, 61% (Found:C, 38.7; H, 3.45; N, 4.35.C,lH,3Br,MoN,03P~0.25CH2C12requires C, 38.55; H, 3.5; N,4.25%).PPh,CH,C(Bu')=NN=CHPh 7a. Benzaldehyde (0.35 cm3,3.44 mmol) was added to a solution containing the phosphinohydrazone 2c (1 .O g, 3.35 mmol) in dry benzene (ca. 5 cm3). After30 min the solvent was removed under reduced pressure and theresidue was triturated with degassed methanol to give therequired product 7a as a pale yellow solid. Yield 0.77 g, 59%(Found: C, 77.8; H, 7.2; N, 7.3. C25H27N2P requires C, 77.7; H,7.05; N, 7.25%).Conversion of the phosphine 7a into the correspondingphosphine oxide 7b. An excess of hydrogen peroxide (0.5 cm3,302, wiv) was added to a solution of the phosphine 7a (0.15 g,0.39 mmol) in ethanol (50 cm3). After 30 min the reactionmixture was poured into water (ca.5 cm3), and the resultantwhite precipitate was filtered off, washed with water and thendried over P205. This gave the required phosphine oxide 7b.Yield 0.12 g, 76% (Found: C, 74.85; H, 6.85; N, 7.15.C,,H,,N,OP requires C, 74.6; H, 6.75; N, 6.95%).[ M o( CO), { PP h CH C( B u ')=NN=CH Ph}] 8a. ( i ) From[Mo(CO),(nbd)]. A solution containing phosphino mixed-azine 7a (0.16 g, 0.14 mmol) and [Mo(CO),(nbd)] (0.15 g, 0.40mmol) in benzene (5 cm3) was put aside at ca. 20 "C for 3 h. TheI Isolution was filtered and the filtrate evaporated to a low volumeunder reduced pressure. The residue was then triturated withmethanol to give the required product 8a as yellowmicrocrystals. Yield 67 mg, 27%.(ii) From [Mo(CO),]. The phosphino mixed-azine 7a (0.67 g,1.75 mmol) and [Mo(CO),] (0.40 g, 1.52 mmol) were refluxedtogether in decane (5 cm3) for 10 min.The resultant red solutiongave a precipitate when it was cooled to ca. 20 "C. This wasfiltered off and recrystallised from dichloromethane-methanolto give the required product 8s as bright orange crystals. Yield0.39 g, 43% (Found: C, 58.4; H, 4.4; N, 4.85. C2,H2,MoN204Prequires C, 58.6; H, 4.6; N, 4.7%). Mass spectrum (fast atombombardment, FAB): m/z 596 ( M + ) , 568 ( M - CO), 540 ( M -2CO), 512 ( M - 3CO) and 484 ( M - 4CO).[ W( C O), { P P h CH , C( Bu ')=NN=C H P h } ] 8b. A solutioncontaining the phosphino mixed-azine 7a (0.15 g, 0.38 mmol)and [W(CO),(nbd)] (0.15 g, 0.38 mmol) in benzene (ca. 5 cm3)was heated under reflux for 20 h.The solvent was then removedunder reduced pressure and the residue triturated withmethanol to give the required product 8b as orange-redmicrocrystals. Yield 0.165 g, 62% (Found: C, 51.1; H, 4.0; N, 4.1.C29H27N204PW requires C, 51.05; H, 4.0; N, 4.1%). Massspectrum (FAB): m/z 682 (M'), 654 ( M - CO), 626 ( M -2CO) and 570 ( M - 4CO).1 I7 [Cr(CO),{PPh,CH,C(Bu')=NN=CHPh}] 8c. This complexwas prepared and isolated in an analogous manner to that ofcomplex 8b, as dark red microcrystals in 62% yield (Found: C,62.4; H, 5.05; N, 4.8. C,,H,,CrN204P requires C, 63.25; H, 4.95;N, 5.1%). Mass spectrum (FAB): m/z 550 ( M + ) , 466 ( M -3CO) and 438 ( M - 4CO).[MOB~,(CO)~{PP~,CH~C(BU')=NN=CHP~)] 9. Themolybdenum(1r) complex 9 was prepared and isolated in ananalogous manner to that of the molybdenum(r1) complex 6, asyellow microcrystals in 62% yield (Found: C, 46.05; H, 3.75; N,3.85. C,,H,,Br,MoN,03P requires C, 46.3; H, 3.75; N, 3.85%).Mass spectrum (FAB): m/z 728 (M').Single-crystal X-Ra-y Diffraction Analysis of Complex 3a.-All crystallographic measurements were carried out on a StoeSTADI4 diffractometer operating in the 0-9 scan mode usingan on-line profile-fitting method and graphite-monochrom-ated Mo-KCX X-radiation (h = 71.069 pm).The data set wascorrected for absorption semiempirically using azimuthal y~scans.The structure was determined via standard heavy-atom (forthe Mo 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. The phenyl groups were treated as rigidbodies with idealised hexagonal symmetry (C-C 139.5 pm). Allhydrogen atoms were included in calculated positions (C-H 96pm) and were refined with an overall isotropic thermal para-meter. The weighting scheme M' = [02(Fo) + 0.0002(F0)2]-'was used. Final non-hydrogen atomic coordinates are given inTable 4.Crystal data. C2,H2,MoN,O4P, M = 534.40, monoclinic,space group P2,/n, a = 892.3(1), b = 1920.1(3), c = 1493.6(3)pm, p = 105.67(1)", U = 2.4639(7) nm3, Z = 4, D, = 1.44 Mgm-3, p = 5.83 cm-', F(OO0) = 1095.82.Data collection. 4.0 < 28 < 50.0°, 4638 data collected, 3530with I > 2.0o(I) considered observed, T = 120 K.Structure refinement. Number of parameters = 281, R =0.0250, R' = 0.0274.AcknowledgementsWe thank the SERC for a postdoctoral research fellowship (toS. D. P.) and for other support. We also thank the committeeof Vice-Chancellors and Principals for an ORS award (toK. K. H.), the trustees of the Lord Boyle Foundation for a2366 J. CHEM. SOC. DALTON TRANS. 1992award (to K. K. H.) and the University of Leeds for aScholarship (to K. K. H.).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 S . D. Perera, B. L. Shaw and M. Thornton-Pett, J. Chem. SOC.,Dalton Trans., 1991, 1183.Chem., 1992,428,59.Dalton Trans., 1992,999.4 S. D. Perera, B. L. Shaw and M. Thornton-Pett, J. Chem. SOC.,5 P. A. S. Smith and E. E. Most, J. Org. Chem., 1957,22, 359.6 G. R. Newkome and D. L. Fishel, J. Org. Chem., 1966,31,677.7 R. Colton and I. B. Tomkins, 1966,19, 1519.8 C. K. Johnson, ORTEP 11, Report ORNL-5138, Oak Ridge National9 W. Clegg, Acta Crystallogr., Sect. A, 1987,37, 22.Determination, University of Cambridge, 1976.Dalton Trans., 1992, 1469.Laboratory, TN, 1976.10 G. M. Sheldrick, SHELX 76, Program System for X-Ray StructureReceived 19th February 1992; Paper 2/00887