Diphosphine derivatives of urea and thioureaPravat Bhattacharyya," Alexandra M. Z. Slawin: Martin B. Smith: David J. Williams" andJ. Derek Woollins *$a Department of Chemistry, Imperial College, London S W7 2A Y, UKDepartment of Chemistry, Loughborough University, Loughborough, Leics. LEI 1 3 TU, UKThe reaction of (Me3Si)HNC(0)NH(SiMe3) or thiourea with PPh,Cl gave Ph,PHNC(E)NHPPh, (E = 0 Ior S 11) which may be oxidised at the phosphorus(Ir1) centres to give Ph,P(E')HNC(E)NHP(E')Ph, (E = 0,E' = 0 111, S IV or Se V; E = S, E' = S VI). Compound I forms simple chelate P,P' complexes with platinumand palladium. The crystal structures of II.Me,SO IV and cis-[PdCl,(Ph,PNHCONHPPh,-P,P'}] havebeen determined.We have recently reported on a number of examples ofcomplexes containing the [R,P(E)NP(E)R,] - anion which isreadily synthesized by N-P bond-forming reactions.However, several aspects of the chemistry of diaza-diphosphapentan-ones and -thiones remain unexplored.Whilethe co-ordination chemistry of a limited number of carb-onyl compounds has been in~estigated,'-~ their thiocarbonylanalogues have been overlooked. One important objective isto determine whether the C=S group has a greater tendency toco-ordinate to metal centres than does the carbonyl group. Theeffect which oxidation at the phosphorus centres has on thereactivity of the molecule concerned is another approach whichis untested. In addition the nitrogen atoms represent furthersites to be exploited, particularly so if deprotonation is anavailable option.Here, we describe the syntheses of(Ph,PNH),CO and its thiocarbonyl analogue (Ph,PNH),CStogether with some examples of their co-ordination compoundsand the formation of the phosphorus(v) species (Ph,PEN-H),CO and (Ph,PSNH),CS. Three illustrative crystal structuresare also reported.ExperimentalGeneral experimental conditions were as described previ-ously. 1,4 Thiourea was dried overnight at 100 "C before use,(Me3SiNH),C0 and PPh,Cl (Aldrich) were used as received.Preparations(Ph,PNH),CO I. A solution of chlorodiphenylphosphine (8.8cm3, 10.8 g, 48 mmol) in toluene (20 cm3) was added dropwiseover a period of 10 min to a stirred suspension of N,N'-bis(trimethylsily1)urea (5.0 g, 24 mmol) in toluene (25 cm3) at70-80°C.After 2 h the toluene was removed in uacuu andhexane (50 cm3) added. The colourless solid was collected bysuction filtration, and washed with further hexane and diethylether. Yield: 9.5 g, 92% [Found (Calc. for C25H,,N,0P,): C,69.15 (70.1); H, 5.10 (5.20); N, 6.55 (6.55%)]. IR (KBr): 3257s,3071m, 3052m, 3012m, 3001w, 1957w, 1884w, 1815w, 1620vs,1586 (sh), 1572 (sh), 1472vs, 1432s, 1402s, 1326w, 1309w,1278w, 1185s, 1097m, 1069w, 1028m, 999m, 970w, 912w, 852w,770s, 742vs, 695vs, 618w, 509s, 486m, 439m, 413w, 398w and318w cm-'.(Ph2PNH),CS 11. A solution of chlorodiphenylphosphine(13.2 cm3, 16.2 g, 73 mmol) in tetrahydrofuran (thf) (30 cm3)was added dropwise over a period of 40 min to a stirredsuspension of thiourea (2.8 g, 37 mmol) and triethylamine (10.3cm3, 7.4 g, 73 mmol) in thf (1 10 cm3).Stirring was continued for45 min, during which time triethylammonium hydrochlorideseparated from the olive-green solution. This precipitate wasremoved by suction filtration, washed with thf (100 cm3) andthe combined filtrates concentrated in uacuo to a green oil.Trituration with ethanol (250 cm3) gave I1 as a colourless solid.Yield: 7.48 g, 46% [Found (Calc. for C25H,,N,P,S): C, 66.5(67.55); H, 5.30 (4.90); N, 5.75 (5.60)%]. IR (KBr): 3220s,3156s, 3061m, 2687w, 2347w, 1952w, 1890w, 1812w, 1457vs,1432s, 1349w, 1307 (sh), 1281s, 1254vs, 11 84m, 1167m, 1128m,1099m, 1069m, 1026m, 1000m, 969w, 944w, 919w, 848w, 742vs,734vs, 694vs, 618w, 577w, 513m, 504m, 498m, 467m, 443w,436w and 39 1 w cm-' .[Ph,P(O)NH] ,CO III.Aqueous hydrogen peroxide (30%w/w, 2 cm3, 16 mmol) was added to a suspension of(Ph,PNH),CO (0.9 g, 2.1 mmol) in thf (30 cm3) at 0 O C and themixture stirred for 10 min. The solution was concentrated to5 cm3 and diethyl ether (50 cm3) added. The colourless pro-duct 111 was collected by suction filtration and washed withfurther diethyl ether. Yield: 0.81 g, 83% [Found (Calc. for(6.10)%]. IR (KBr): 3226m (br), 31 50m, 3058m, 2898w, 171 5s,1471vs, 1439vs, 1253m, 1183s, 1127s, 1104s, 1072w, 1028w,998w, 914w, 854w, 811m, 771m, 751s, 726s, 693s, 626w, 570m,532s, 51 lm and 428w cm-'.C,sH,,N,O3P,): C, 63.2 (65.2); H, 4.70 (4.80); N, 5.95[Ph,P(E)NH],CO (E = S IV or Se V) and [Ph,P(S)NH],CSVI. These compounds were prepared by the same generalprocedure. The compounds (Ph,PNH),CO or (Ph,PNH),CS(2 mmol) and the appropriate chalcogen (2-2.5 mmol) wereheated to reflux in toluene (20 cm3) for 10-20 min. The hotsolution was filtered through Celite and the solvent removedfrom the filtrate in oacuo.The crude product was recrystallisedfrom CH,Cl,-hexane at -20 "C. Yields were typically 60-80%.Compound IV [Found (Calc. for C25H,,N,0P,S,): C, 59.9(60.95); H, 4.50 (4.15); N, 5.80 (5.70)X-J. IR (KBr) 3096s,3057m, 2915w, 2809w, 1985w, 1909w, 1810w, 1668vs, 1471s,1436s, 1426s, 1338w, 1308w, 1257m, 1185w, 1158w, 1104s,1066m, 1027w, 998w, 874m, 851w, 791w, 749m, 723s, 689s,665m, 647m, 615w, 587w, 533s, 503m, 495s, 468w, 443w, 392m,360w and 340w cm-'. Compound V [Found (Calc.forC,,H,,N,0P,Se2): C, 50.45 (51.2); H, 3.85 (3.80); N, 4.95(4.80)%]: IR (KBr) 3328m, 3125s,3052s, 2781w, 1965w, 1909w,1817w, 1683vs, 1480s, 1436vs, 1410s, 1336w, 1310w, 1277w,1255m, 1182w, 1159w, 1107s, 1 lOOs, 1070w, 1049m, 1027m,998m, 923w, 878m, 842w, 749s, 717s, 704s, 690s, 633m, 618w,565s, 523s, 489m, 473m and 369m cm-'. Compound VI [Found(Calc. for C25H22N2P2S3): C, 58:15 (59.05); H, 4.20 (4.35); N,J. Chem. Soc., Dalton Trans., 1996, Pages 3647-3651 3645.45 (5.50)%]. IR (KBr): 3075s, 3056s, 2902w, 2873w, 1501s,1481m, 1449m, 1437s, 1294m, 1270m, 1191s, 1181s, 1160m,l l l l s , 1102s, 1070w, 1028w, 998m, 962m, 829s, 754m, 739s,731s, 721s, 690s, 673m, 645m, 627m, 613m, 557s, 512s, 496m,482m, 472m, 453w, 429w, 366w, 354w and 341w cm-'.cis-[PtCl,{Ph,PNHCONHPPh,-P,P}] 1. To a solution of[PtCl,(cod)] (cod = cycloocta-l,5-diene) (0.052 g, 0.139 mmol)in dichloromethane (5 cm3) was added solid Ph,PNHCO-CONHPPh, (0.060 g, 0.140 mmol).After stirring for ca. 17 hthe white solid was collected by suction filtration. Yield: 0.078g, 81%. Concentration of the filtrate by evaporation underreduced pressure to (ca. 1-2 cm3) and addition of diethylether (10 cm3) gave an additional crop of cis-CPtC1,-{Ph,PNHCONHPPh,-P,P'}] [Found (Calc. for C25H22-Cl,N,OP,Pt): C, 42.85 (43.25); H, 3.25 (3.2); N, 4.1 (4.05)%].Selected NMR (Me,SO-C,D,) and IR data: 31P-{1H} NMR(KBr disc) 3326,3145 [v(N-H)]; 1673 [v(C==O)]; 324,303 cm-'6(P) 40.6, ' J(PtP) 3779 Hz; lg5Pt-{ 'H) NMR 6(Pt) -4545; IR[v(Pt-Cl)].cis-[PdCl,(Ph,PNHCONHPPh,-P,P}] 2.To a yellowsolution of [PdCl,(cod)] (0.075 g, 0.263 mmol) in dichlorometh-ane (10 cm3) was added solid Ph,PNHCONHPPh, (0.1 13 g,0.264 mmol). The solution turned pale yellow and after furtherstirring (ca. 90 min) the solid product deposited and wascollected by suction filtration. Yield: 0.107 g, 67%. A secondcrop (0.050 g) was obtained upon reducing the volume of thefiltrate under reduced pressure and addition of diethyl ether (20cm3) [Found (Calc. for C2,H,,C12N,0P,Pd): C, 46.45 (49.55);H, 3.6 (3.65); N, 4.7 (4.65)%]. Selected NMR and IR data: "P-{'H} NMR (Me,SO-C,D,) 6(P) 62.9; IR(KBr disc) 3319,3143[v(N-H)]; 1672 [v(C=O)]; 313, 304 cm-' [v(Pd-Cl)]. Clearcrystals suitable for X-ray crystallography were obtained fromCHCl,.cis-[PtMe,{Ph,PNHCONHPPh,-P,P')] 3.To a solution of[PtMe,(cod)] (0.040 g, 0.120 mmol) in dichloromethane (1 5cm3) was added solid Ph,PNHCONHPPh, (0.051 g, 0.120mmol) and the colourless solution stirred for ca. 30 min. Thevolume was reduced under reduced pressure to ca. 1-2 cm3 anddiethyl ether (20 cm3) added. The white product was collectedby suction filtration. Yield: 0.070 g, 90% [Found (Calc. forC2,H2,N,0P,Pt): C, 49.75 (49.6); H, 3.80 (4.35); N, 3.80(4.3)%]. Selected NMR (CDCl,) and IR data: ,'P-{ 'H} NMRNMR 6(H) 6.23, ,J(PtH) 25.5 Hz (NH); IR (KBr disc) 3350,3147 [v(N-H)]; 1662 cm-' [v(C==O)].6(P) 62.7, 'J(PtP) 1931; 195Pt-{'H} NMR 6(Pt) -4699; 'Hcis-[PtMe(Cl){Ph,PNHCONHPPh,-P,P'}] 4. To the solids[PtMe(Cl)(cod)] (0.013 g, 0.037 mmol) and Ph,PNHCO-NHPPh, (0.016 g, 0.037 mmol) was added CDCl, (0.7 cm3)and the reaction immediately monitored by 31P-{1H} NMRspectroscopy.The exclusive phosphorus-containing speciesobserved after ca. 5 min was identified as cis-[PtMe-(Cl){Ph,PNHCONHPPh,-P,P'}] and could be isolated byaddition of diethyl ether (10 cm3) to the CDC1, solution. Thewhite product was collected by suction filtration. Yield: 0.022 g,88% [Found (Calc. for C2,H,&lN2OP2Pt): C, 45.65 (46.35);H, 3.5 (3.75); N, 4.3 (4.15)%]. Selected NMR (CDC1,) and IRdata: 31P-{ 'H) NMR &(PA trans to CH,) 60.7, J(PtPA) 1834,6(PB trans to C1) 52.4, 'J(PtP,) 4483, 2J(PAPB) 24.2; 195Pt-{'H}NMR 6(Pt) -4618; 'H NMR 6(H) 6.16 C3J(PtH) 67.11 and5.95 C3J(PtH) 34.6 Hz] (both NH); IR (KBr disc) 3343, 3145[v(N-H)], 1667 [v(C==O)]; 303 cm-I [v(Pt-Cl)].CrystallographyDetails of the data collections and refinement parameters aregiven in Table 1.All determinations were performed at roomtemperature using Cu-KE radiation and o scans. The structureswere solved by direct methods (II*Me,SO, IV) or the heavy-atom method (2) and all non-hydrogen atoms refinedanisotropically . Absorption corrections were made with theprogram DIFABS unless stated otherwise. The hydrogenatoms were refined in idealised positions. In II*Me,SO thesolvate molecule is disordered about the C2 axis. Calculationswere performed using SHELXTL or teXsan. 'Atomic coordinates, thermal parameters and bond lengthsand angles have been deposited at the Cambridge Crystallo-graphic Data Centre (CCDC).See Instructions for Authors,J. Chem. SOC., Dalton Trans., 1996, Issue 1. Any request to theCCDC for this material should quote the full literature citationand the reference number 186/187.Results and DiscussionThe reaction between PPh,Cl and commercially availableN,N-bis(trimethylsily1)urea proceeds in toluene at 70-80 "Cto give Ph,PNHC(O)NHPPh, I [equation (l)]. Addition of2PPh2Cl + (Me,SiNH),CO --+Ph,PNHC(O)NHPPh, + 2SiMe3C1 (1)the chlorophosphine to the urea suspension leads to rapiddissolution of the urea followed within minutes by precipitationof colourless I, often leading to a viscous mixture which resistsstirring. Removal of the solvent in uacuo followed by washing ofthe precipitate with hexane leads to near-quantitative recoveryof this product.Air- and moisture-tolerant, I is readily solubleonly in Me,SO, due perhaps to strong intermolecular hydrogenbonding between the carbonyl group and amine protons ofadjacent molecules in the solid state. The infrared spectrumcontains a sharp band at 3257 cm-' which corresponds tov(NH), suggesting that intermolecular hydrogen bonding isrelatively weak. The v(C0) absorption is at 1620 cm-'; v(CN) isassigned to the intense band at 1472 cm-' .Whilst Schmutzler and co-workers '' reported that themonosulfide Ph,P-P(S)Ph, is the only phosphorus-containingproduct from the reaction between PPh,Cl and thiourea, wefind that in thf at room temperature the thiocarbonyl analogueof diphosphine I, Ph,PNHC(S)NHPPh, 11, can be prepared[equation (2)]. Accompanying consumption of the insoluble2PPh2Cl + NH,C(S)NH, + 2NEt3-Ph,PNHC(S)NHPPh, + 2mEt,H]Cl (2)thiourea is precipitation of mEt,H]Cl, the supernatantsolution turning green as this mildly exothermic reactionproceeds.Removal of the ammonium salt by filtration,evaporation of the thf in uacuo and trituration of the resultantgreen oil with ethanol gives I1 in typically 46% yield.Following collection by suction filtration, concentration of theethanol filtrate leads to isolation of the more soluble by-products, of which Ph,P-P(S)Ph, [6(P) 47.8 and - 11.6, ' J(P-P) 254 Hz] is the most abundant. While the position of thetrimethylsilyl groups in (Me,SiNH),CO dictates the regioselec-tivity in its reaction with PPh2C1, there is no such control forthiourea. Thus it is conceivable that other molecules suchas Ph,PNHC(S)NH, or (Ph,P),NC(S)NH, are among theproducts.There are two minor differences between oursynthetic procedure and that of Schmutzler and co-workers.First, we have employed a shorter reaction time (45 min us. 5 h)and secondly addition of the chlorophosphine is performed atroom temperature over a period of 10 min, as opposed to at-20 "C. The effects of these changes are hard to quantify, butthey are sufficient to allow us to generate I1 in moderate yield.Unlike the carbonyl compound I, I1 is moderately soluble in arange of solvents such as Me,SO, thf, acetone or CHCl,. Itdecomposes more rapidly in solution than I, giving rise to as yet3648 J.Chem. SOC., Dalton Trans., 1996, Pages 3647-365Table 1 Details of the X-ray data collections and refinementsIbMe,SO aEmpirical formulaMColour, habitCrystal size/mmCrystal systemSpace groupalAb/ACIAPI"u/A3ZDJMg mL3p/mm-'20 rangerF(o00)Independent reflections (Rin,)Observed reflectionsNo. parameters refinedData/parameter ratioAbsorption correctionMinimum, maximum transmissionp in weighting schemeFinal R, R'Largest A/aLargest difference peak, hole/e A-3C25H22NzPzS*CzH60S522.6Colourless, square plate0.30 x 0.30 x 0.06OrthorhombicPbcn9.742(2)1 1.339(2)28.059( 3)276841.253.0010962299174216110.811Face indexed0.45,0.820.00050.0465,0,05240.0 120.34, -0.253-1 28IVb:;;;22N2OP2S2Clear, block0.32 x 0.48 x 0.63Monoclinic1 1.755( 1)9.163(2)22.697( 2)95.578(8)243341.343.346-12010243902 (0.039)337531210.811DIFABS0.82, 1.000.00500.035,0.0410.06E 1 l n0.26, -0.252*H20C2 =,H22Cl,N2OP2Pd*H20623.13Clear, prism0.18 x 0.21 x 0.29Monoclinicp2 1 In12.322(4)15.726(3)13.926(3)90.69(2)269841.538.696-120125641 99 (0.040)27523088.911DIFABS0.52, 0.0030 1.000.060,0.0530.100.68, -0.90Siemens P4/PC diffractometer, SHELXTL, F > 4.0o(F), refinement on F with w-' = 02(F) + p p .Rigaku AFC7S diffractometer, teXsan,I > 3.0o(T), refinement on Fwith w-' = oz(F) + p p .Fig.1 Crystal structure of Ph,PNHC(S)NHPPh,-Me,SOuncharacterised products; as a solid it is best stored undernitrogen.Allowing a hot saturated Me2S0 solution of compound I1 tocool slowly to room temperature gave crystals of Ph2PNHC-(S)NHPPh2-Me2S0 which were suitable for X-ray analysis.Selected structural data are contained in Table 2. The moleculepossesses (Fig. 1) crystallographic C2 symmetry about the C-Sbond, with one molecule of disordered Me2S0 solvate present.The PN(CS)NP backbone of the structure is planar (maximumdeviation from the mean plane 0.003 A), consistent with an sp2hybridisation of the nitrogen atoms and C(31). The pyramidalgeometry at phosphorus is somewhat distorted with all of theangles substantially less than 109". There is strong hydrogenbonding between the amine protons and the oxygen atom of theMe2S0 molecule CH(30) O(41) 1.99, 0 N 2.82 A,N-H 0 154'1 which, in conjunction with the bulkiness ofthe phosphine substituents, is responsible for the syn,synorientation of the nitrogen-phosphorus bonds relative toC(31)-S(32); this, notably, is opposite to the conformationgenerally adopted by diphosphines of this type.5 * ' 2-1Consequently the non-bonded P P distance of 5.44 A greatlyTable 2(S)NHPPh2*Me2S0Selected bond lengths (A) and angles (") for Ph,PNHC-P( 1 W(30) 1.7 19(2) N( 30)-C(3 1) 1.357(3)C( 3 1 )-S( 32) 1.660(4) Mean P-C (aryl) 1.83N(30)-C(3 1 )-S(32) 123.5(2) N(30)-C(3 1 )-N(30A) 1 1 3.1 (3)C(20)-P( 1 )-N( 30) 1 0 1.9( 1) C( 1 0)-P( 1 )-N( 30) 98.4(1)P(I)-N(30)-C(31) 124.0(2) C(lO)-P(l)-C(20) 100.0(1)exceeds the range of typical values (2.80-3.00 A), whilst the C-S,P-N and N-C bond lengths are comparable to those found inrelated structures.'*12-16 For II-Me2S0 the non-bondedP S distance is 3.23 A and the N N separation is 2.27 A.For the thiocarbonyl I1 the v(NH) bands appear at 3220 and3156 cm-I with v(CN) at 1457 cm-'. The infrared spectrum ofII-Me2S0 contains considerably more bands than the spectraobtained from batches free of solvate, as a consequence of thehydrogen bonding observed in the solid state and absorptionsof the Me,SO molecule.Consistent with their structure, the 31P NMR spectra ofcompounds I and I1 are singlets, while in the 13C NMR thecarbonyl resonances [S(13C) in Table 31 appear as triplets as aresult of ' J coupling to two equivalent phosphorus nuclei.Positive-ion FAB mass spectrometry further verifies theiridentity as diphosphines.Oxidation of compound I by hydrogen peroxide, sulfur orselenium leads to phosphorus(v) derivatives Ph,P(E)NH-C(O)NHP(E)Ph, (E = 0 111, S IV or Se V) [equations (3) and(4)].The dioxide I11 has previously been prepared from(Ph2PNH)zCO + H20, - [Ph2P(O)NH]2CO (3)I11(Ph2PNH),C0 + 2 E - [Ph,P(E)NH],CO (4)E = SIVorSeVPh,PNCNPPh, or Ph,P(O)NCNP(O)Ph, l 7 and by conden-sation of smaller fragments. There is little agreement betweenthe published infrared spectral data I 7 and our own, however nochemical shift data have been reported which can confirmJ. Chem. SOC., Dalton Trans., 1996, Pages 3647-3651 364Table 3 The 31P-{1H}, 13C-{1H} NMR and positive-ion FAB mass spectrometric data for the diphosphinesCompound Solvent S(31P) S('3C) 2J(P-C)/Hz mi2I1 (CD3)2S0 30.8 189.2 24.0 443Iv CDCl, 52.2 154.7 493V CDCl, 47.0 153.6 -VI CDCl, 53.0 183.2 -I (CD3)2S0 25.1 159.3 17.0 42846 1 rn (CD3)2S0 19.5 152.2 a589508--a Spectrum recorded in CH,OD.1J(31P-77Se) 784 Hz.identification. The disulfide N and diselenide V have not beenpreviously reported. The compounds are air-stable colourlesssolids, IV and V being soluble in chlorinated solvents, I11 onlypartially soluble in methanol or Me,SO.While the oxidation of compound I1 by sulfur proceeds inrefluxing toluene to give the disulfide Ph,P(S)NHC(S)NHP-(S)Ph, VI we have been unable to isolate samples of thethiocarbonyl analogues of IV and V.Treatment of I1 withaqueous H202 at 0°C converts the G S group into C==O inaddition to oxidation of the phosphorus centres, giving[Ph,P(O)NH],CO, confirmed by 31P NMR and infraredspectroscopy; the reaction between I1 and selenium in refluxingtoluene or in thf at room temperature leads to a mixture ofunidentified compounds according to 'P NMR spectroscopy.A singlet at 6 48.0 with selenium satellites [1J(31P-77Se) 801 Hz]may correspond to the desired product, but we have no furtherevidence to support this as all attempts at separation havefailed.The dioxidised derivatives display singlets in theirphosphorus-31 NMR spectra (Table 3), with 77Se satellites forV.No 2J(31P-'3C) couplings between the phosphorus nucleiand the carbon atom of the carbonyl or thiocarbonyl groupwere resolved. In the infrared spectra, oxidation of I lowers6(NH) by over 100 cm-' and increases v(C0) by 50-100 cm-'for I11 and IV. The former may arise from greater intermolecularhydrogen bonding compared with I. There is a shift to lowfrequency of the carbonyl resonance in the 13C NMR spectrumupon oxidation; a correlation exists with v(C0) in thevibrational spectra for I and 111, IV. The increase in v(C0) andhence of C-0 bond order upon oxidation of I indicates areduction in the contributions of N=C-OH tautomers, as aresult of the electron-withdrawing influences of the adjacentphosphorus(v) centres; the v(CN) frequencies seem oblivious tothe effects of oxidation (1471, 1471 and 1480 cm-' for 111, IVand V respectively, cJ: 1472 cm-' for 1).We assign strong bandsat 647 and 565 cm-' in the infrared spectra of IV and V to thev(PS) and v(PSe) stretches respectively; for 111 v(P0) appears asan intense absorption at 1183 m-'. For M the v(NH) bandsoverlap with the v(C-H) vibrations of the phenyl rings. Byanalogy with IV we assign an absorption of medium intensity at645 cm-' to v(PS).In the solid state compound IV exists (Table 4, Fig. 2) withP(1)-S( 1) in an approximately syn orientation to C(13)-0(1),S(2)-P(2) being anti with respect to C(13)-0(1). This isintermediate between the syn,syn orientation of the diphenyl-phosphino substituents in 11 and the anti,anti conformationadopted by other linear diazadiphosphapentan-ones and-thiones.5 9 1 2 * 1 4 3 1 There is an intramolecular hydrogen bond[H(ln) S(2) 2.20, N(l) S(2) 3.10 A, N-H S(2) 146'1as well as intermolecular hydrogen-bonding interactionsbetween the 0(1) and H(2) atoms of adjacent moleculesO(l*) 175.3'1 which, combined with the steric bulk of thediphenylphosphinothioyl moieties, dictates the molecularconformation. Overall P( 1)-N( 1 )-C( 13)-O( l)-N(2)-P(2)-S(2)are close to planar [maximum deviation from the mean plane0.11 A for O(l)] with S(l) lying 1.42 A from this plane. The[H(2) * O(l*) 1.86, N(2) - 0(1*) 2.81 A, N(2)-H(2)Table 4 Selected bond lengths (A) and angles (") for Ph,P(S)NHC(O)-NHP(S)Ph,114.6(1) N(l)-P(l FS(1) 116.07(9) N(2)-P(2)-S(2)P(2)-N(2)-C( 13) 134.6(2) C( 13)-N( 1 )-P( 1) 121.8(2)O( 1 )-C( 1 3)-N( 1) 1 2 1.9(2) O(l)-C(13)-N(2) 12042)N(2)-C(13)-N(l) 117.7(2)Fig.2 Crystal structure of Ph,P(S)NHC(O)NHP(S)Ph,phosphorus-nitrogen and -sulfur bond lengths are inequivalentwith P(2)-N(2) and P(1)-S(l) being the shorter within eachpair. The N(l)-C(13) and N(2)-C(13) distances are the samewithin' statistical significance. The P(2)-N(2)-C( 13) angle issubstantially more open than C( 13)-N( 1 )-P( 1) [ 134.5(2) and121.8(2)" respectively]; despite this enlargement the nitrogenatoms and C(13) are essentially sp2 hybridised. Overall, theP-N, N-C and C-O bond lengths for N are comparable withthe corresponding parameters in related structure^.^*^^^'^*^As would be expected, reaction of compound I with[ML,(cod)] (L = C1 or Me, M = Pd or Pt) proceeds smoothlywith displacement of cod and formation of P,P-chelatecomplexes 1-4.The new complexes gave satisfactory3650 J, Chem. Sac., Dalton Trans., 1996, Pages 3647-365Table 5 Selected bond lengths (A) and angles (") for cis-CpdCl2 { Ph 2 PNHCONHPPh, -P,P' f ]2.3 59( 3)2.200( 3)1.680(7)1.362( 11)1.226( 1 1)93.2(1)88.1(1)114.7(3)126.7(7)12 1.7( 10)2.340(2)2.2 16(2)1.687(8)1.389( 12)91.4(1)87.7(1)130.5(7)119.5(9)11 5.9(3)N(2)Fig. 3 Crystal structure of cis-~dC1,(Ph2PNHCONHPPh,-P,P'}](a) showing the dimer pair formation and (b) the core illustrating thepseudo-boat conformation of the ringmicroanalyses and NMR and IR spectra which allowedidentification as simple chelate metal@) complexes.The crystalstructure of 2-H20 reveals (Table 5, Fig. 3) that the square-planar palladium centre [maximum deviation from the Pd-Cl(l*)-Cl(2)-P(l)-P(2) mean plane 0.18 8, for C1(2)] is part ofa puckered pseudo-boat-like six-membered PdP,N,C ring withthe co-ordination plane and the P(1)-N( l)-N(2)-C( 1) meanplanes being inclined by 36". Within the metallacycle thereappears to have been some slight contractions in the P-N bondlengths compared to II=Me2S0, though whether this is aconsequence of co-ordination or the change from a 0 to aC=S group is difficult to judge. The backbone of the ligand in2=H20 is involved in a pair of hydrogen bonds (about acrystallographic centre of symmetry) to adjacent moleculesCH(2n) O( 1 *) 1.95, N(2) O( 1 *) 2.80 8,, N(2)-H(2n) O( 1 *) 15 lo] to form dimer pairs of molecules.TheH,O solvate is hydrogen bonded to the other N-H groupof the ligand backbone [H(ln) O(2) 1.74, N( 1) O(2)2.75 8,, N(1)-H(1n) O(2) 144'1.References1 J. R. Phillips, A. M. Z. Slawin, A. J. P. White, D. J. Williams andJ. D. Woollins, J. Chem. SOC., Dalton Trans., 1995,2467.2 J. D. Woollins, J. Chem. SOC., Dalton Trans., 1996,2893.3 D. Cupertino, R. W. Keyte, A. M. Z. Slawin, D. J. Williams and4 A. M. Z. Slawin, M. B. Smith and J. D. Woollins, J. Chem. Soc.,5 R. Vogt, P. G. Jones, A. Kolbe and R. Schmutzler, Chem. Ber., 199 1,6 P. B. Hitchcock, S. Morton and J. F. Nixon, J. Chem. SOC., Dalton7 W. Krueger, R. Schmutzler, H. M. Schiebel and V. Wray,8 DIFABS, N. G. Walker and D. Stuart, Acta Crystallogr., Sect. A ,9 G. M. Sheldrick, SHELXTL, Siemens Analytical instruments,10 teXsan, Crystal Structure Analysis Package, Molecular Structure11 M. Gruber, P. G. Jones and R. Schmutzler, Chem. Ber., 1990, 123,12 G. Bettermann, R. Schmutzler, S. Pohl and U. Thewalt, Polyhedron,13 H. Riffel, S. Kleemann, H. Hess and E. Fluck, Z. Anorg. Allg. Chem.,14 M. Gruber; P. G. Jones and R. Schmutzler, Phosphorus Sulfur15 M. Gruber, R. Schmutzler and D. Schomburg, Phosphorus Sulfur16 S . Kleemann, E. Fluckand W. Schwarz, 2. Anorg. Allg. Chem., 1981,17 A. Weisz and K. Utvary, Monatsh. Chem., 1968,99,2498.18 K. Utvary, E. Freundlinger and V. Gutmann, Monatsh. Chem.,J. D. Woollins, Inorg. Chem., 1996,35,2695.Dalton Trans., 1996, 1283.124,2705.Trans., 1985, 1295.Polyhedron, 1989,8,293.1983,39, 158.Madison, WI, 1990.Corporation, The Woodlands, TX, 1985 and 1992.1313.1987,6, 1823.1984,508, 61.Silicon Relat. Elem., 1993,80, 195.Silicon Relat. Elem., 1993,80,205.475, 137.1966,97,348.Received 28th May 1996; Paper 6/03700CJ. Chem. Soc., Dalton Trans., 1996, Pages 3647-3651 365