role of an electric polarizability has not been deter-deviation from electroneutrality while macromined. (This probably makes no difference in the scopically short, is long compared to the correlaformal result.) Secondly and more seriously it tion time of the C\. This is probably not true for a has been assumed that the relaxation time for a very high concentration of ions.

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The tris(cyanoethy1)phosphine complex [Pt{ P(CH2CH2CN)3}3] catalyses the addition of PH3 or PH(CH2CH2CN)2 to CH2=CHCN to give P(CH2CH2CN)3.Metal-phosphines catalyse many HX additions to alkenes including hydrogenation,1,2 hydroformylation,3 hydrosilyl-ation4 and more recently, hydroamination.5 We now report the first example of a hydrophosphination of an alkene catalysed by a metal complex.Tris(cyanoethy1)phosphine is an air-stable, white solid which finds use in the photographic industry6 and has been extensively investigated as a ligand.7 We have recently shown* the PH3 addition to H2C=0 to give P(CH20H)3 is catalysed by a platinum(0) complex of P(CH20H)3 and we therefore reasoned that platinum(0) complexes of P(CH2CH2CN)3 may catalyse the addition of PH3 to CH2=CHCN. Platinum(0) complexes of P(CH2CH2CN)3 have not been reported so the routes shown in Scheme 1 have been developed for the synthesis of [Pt{ P(CH2CH2CN)3}3] 1. The three-coordination of the platinum(0) in complex 1 is deduced from its 195Pt{lH} NMR spectrum, which is a 1 : 3 : 3 : 1 quartet, and has been confirmed by elemental analysis, and 'H, 13C{ IH}, and 31P{ 'H} NMR spectroscopy.? The 31P{lH} NMR spectrum of a (CD3)2S0 of complex 1 containing an excess of t Selected N M R spectroscopic data: all spectra were recorded in (CD&SO (3lP and I95Pt chemical shifts are to high frequency of 85% H3P04 and 5 21.4 MHz respectively). 1: S(P) 39.9, lJ(PtP) 4217 Hz; S(Pt) + 15.8 (quartet).

The addition of PH, to formaldehyde to give P(CH,OH), is catalysed by a range of platinum-(iv), -(II) and2 and [Pt{P(CH,OH),},]~H,O 3. A large ratio of P(CH,OH), to Pt is present under the conditions in which the catalysis is operated and the hypothesis that a common platinum-P(CH,OH), complex is present under these conditions has been tested. It is shown that Na,[PtC16] is reduced by 3 equivalents of P(CH,OH), to give [PtCI,{P(CH,OH),},] 2, the same species that is formed upon addition of 2 equivalents of P(CH,OH), t o K,[PtCI,]. Addition of 1 equivalent of P(CH,OH), t o 2 gives [PtCI{P(CH,OH),}],CI 4a while addition of 2 equivalents of P(CH,OH), to 2 gives an unstable species, tentatively assigned the five-co-ordinate structure [PtCI{P(CH,OH),},]CI 5a. In the presence of further P(CH,OH),, 5a decomposes smoothly t o give a mixture of [PtH{P(CH,OH),},]CI 3b, [P(CH,OH),]CI and the unusual bis(che1ate) salts trans-and cis-[Pt{(HOCH,),PCH,0P(CH20H),},]CI,6a and 6b. A mechanism rationalising this reaction is presented. The pH of the reaction medium during the catalysis is ca. 9-10 and it is therefore concluded that [Pt{P(CH,OH),},] 3a is the main platinum-containing species present during all the platinum catalysed reactions. It is shown that [Ni{P(CH,OH),},] 18 and [Pd{P(CH,OH),},] 19 are also catalysts for the hydrophosphination of formaldehyde and a general mechanism is suggested.

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The noncomplexed ligand Ph 2 PNHP(O)Ph 2 (HL) has been prepared, for the first time, from Ph 2 PNHPPh 2 (dppa) and H 2 O 2 in moderate yield. On further treatment with H 2 O 2 the phosphine oxide Ph 2 P(O)NHP(O)Ph 2 (1) can be formed. Reaction of [MCl 2 (COD)] (M ) Pt or Pd; COD ) cycloocta-1,5-diene) with 2 molar equiv of HL affords [MCl 2 (HL) 2 ] (4, 5) in which both ligands are monodentate P-bound. The analogous dibromo and diiodo derivatives [MX 2 (HL) 2 ] (6-9) were prepared from either [MX 2 (COD)] (M ) Pt or Pd; X ) Br or I) and HL or treatment of [MCl 2 (HL) 2 ] with an excess of NaI. Facile base deprotonation of the amine proton in 4 or 5 affords a new class of metallacycles [M(L) 2 ] [L -) Ph 2 PNP(O)Ph 2 -] (10, 11) incorporating two five-membered M-P-N-P-O rings. Compound 10 was independently made from [Pt(CH 3 ) 2 (COD)] and 2 equiv of HL in toluene at ambient temperature whereas the reaction of [Pt(CH 3 )Cl(COD)] with 2 equiv of HL affords solely trans-[Pt-(CH 3 )Cl(HL) 2 ] (13). Protonation of the neutral compound 10 with HCl in ethanol regenerates the ring-opened cis complex 4. In contrast, addition of HBF 4 ‚OEt 2 to 10 (or 11) results in exclusive protonation at the nitrogen atom of the chelating ligands to give cis-[M{Ph 2 PNHP(O)Ph 2 -P,O} 2 ][BF 4 ] 2 (15, 16); both chelate rings remain intact. The dicationic compounds 15, 16 can also be synthesized from 4, 5 in dichloromethane using Ag[BF 4 ] as a chloride abstractor. All new compounds described have been characterized by a combination of multinuclear NMR spectroscopy, IR spectroscopy, and elemental analyses. The molecular structures of Ph 2 PNHP(O)Ph 2 , cis-[PtBr 2 {Ph 2 PNHP(O)Ph 2 -P} 2 ], cis-[Pt{Ph 2 PNP(O)Ph 2 -P,O} 2 ], trans-[Pt(CH 3 )Cl{Ph 2 PNHP(O)Ph 2 -P} 2 ] and cis-[Pt{Ph 2 PNHP(O)Ph 2 -P,O} 2 ][BF 4 ] 2 have been determined by single-crystal X-ray diffraction. Crystals of HL are triclinic, space group P1 h, with a ) 10.410(2) Å, b ) 12.083(2) Å, c ) 9.036(4) Å, R ) 103.05(2)°, ) 99.09-(2)°, γ ) 72.98(1)°, V ) 1054 Å 3 , and Z ) 2. The final R and R w values were 0.061 and 0.047, respectively. Crystals of 6 are triclinic, space group P1 h, with a ) 13.113(4) Å, b ) 15.996(4) Å, c ) 13.011(4) Å, R ) 102.65(3)°, ) 117.39(2)°, γ ) 101.03(2)°, V ) 2225 Å 3 , and Z ) 2. The final R and R w values were 0.039 and 0.031, respectively. Crystals of 10 are monoclinic, space group P2 1 /a, with a ) 17.600(13) Å, b ) 13.498-(10) Å, c ) 18.641(9) Å, ) 105.13(1)°, V ) 4274 Å 3 , and Z ) 4. The final R and R w values were 0.041 and 0.036, respectively. Crystals of 13 are triclinic, space group P1 h, with a ) 14.686(2) Å, b ) 18.735(2) Å, c ) 9.018(3) Å, R ) 91.71(2)°, ) 102.27(2)°, γ ) 68.54(1)°, V ) 2253 Å 3 , and Z ) 2. The final R and R w values were 0.041 and 0.044, respectively. Crystals of 15 are orthorhombic, space group P2 1 2 1 2, with a ) 14.100(2) Å, b ) 19.002(1) Å, c ) 9.145(2) Å, V ) 2450 Å 3 , and Z ) 2. The final R and R w values were 0.052 and 0.057, respectively. The P-bound monodentate complexes contain ligands with similar...

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