No abstract

No abstract

The quasi-planar 64-electron butterfly cluster [ R U ~( C O ) ~~( ~-P P ~~) ~] reacts with dihydrogen under photolysis giving the 60-electron tetrahedral cluster [H2R~4(CO)10(p-PPh2)2], a transformation which can be reversed under a pressure of carbon monoxide; the two hydride ligands in the unsymmetric [H2R~4(CO)lo(p-PPh2)2] have been located via a single crystal X-ray analysis.

No abstract

Reactions of the diplatinum(0) complex [Pt,(p-dppm),] (I) with H2S and RSH, R = alkyl or aryl, have been studied. With H2S the products were [Pt,H,(p-S) (p-dppm),] (2) and the cation [Pt,H (p,-S) (p-dppm),] +, probably as the HS-salt. With RSH the products using an excess of thiol were usually [Pt(SR),( dppm)] (4; R = Me, Et, But, CH,CO,Et, Ph, 4-MeC,H4, or PhCH,). With HSCH,CH,SH the chelate complex [ Pt(SCH,CH,S) (dppm)] (5) was formed. Intermediate binuclear complexes were identified as [Pt,H(SR)(p-dppm),] (7) when R = Et, and [Pt,(SR),-(p-dppm),] (6) when R = Ph or 4-MeC,H4. With PhCH,SH, a major product was the 'A-frame' complex [Pt,(p-S) (SCH,Ph),(p-dppm),] (8) whose structure has been determined by X-ray diffraction. [Rh2(p-S)(CO),(p-dppm)2].' * Much of this chemistry has been carried out in order better to understand technological processes involving H2S and RSH.'9*20 and CPd2C1,(CL-s>(~-dPPm)21,' ' CPt2H,(~-H)(~-dPPm)2lrpF~~ ResultsReaction with H,S.-A brief survey of the main results is shown in the Scheme. Complex (1) reacted rapidly with H2S(g) to give a yellow precipitate and a light yellow supernatant solution. These fractions were separated and the products were characterized spectroscopically. The yellow precipitate, (2), was shown to have the structure [Pt2H2(p-S)(p-dppm)2] while the soluble product was shown to contain the known cation [Pt3H(p3-S)(p-dppm),] +:,' (3), presumably as the HS-salt.The structure of complex (2) was deduced from the i.r., 'H, and ,'P-{ 'H} n.m.r. spectra. The i.r. spectrum contained a peak at 2 090 cm-' due to a terminal metal-hydride bond stretch. The 'H n.m.r. spectrum confirmed the terminal hydride, which gave a resonance at 6 -7.3 with 'J(PtH) = 1 191 Hz. The P,CH, proton signals appeared as two resonances at 6 3.94 and 5.82. The pattern for these signals was very similar to that observed for [Pt,Cl,(p-S)(p-dppm),] and is characteristic for A-frame structures.16 The 'P-{ 'H} n.m.r. spectrum was typical of a symmetrical A-frame complex,' containing a singlet peak at 9.6 p.p.m. with satellites due to both 'J(PtP) and 2J(PtP) couplings and with a 'J(PtP) value of 2950 Hz characteristic of compounds with trans-Pt,(p-dppm), groups. The spectra did not change at low temperatures down to -80 "C.Complex (3), as the PF6salt, has been synthesized previously by the reaction of the triplatinum cluster [Pt3(p3-C0)-(p-dppm)3][PF& with H,S(g),,' and the cation was identified by comparison of the 'H and ,'P n.m.r. spectra with those of an authentic sample.Reactions with Thiols RSH.-Complex (1) reacted slowly with excess of methanethiol in toluene solution over a period of several hours to give [Pt(SMe),(dppm)] (4a). The 'H n.m.r. spectrum contained a singlet a 6 2.1 due to the SMe protons, and a triplet at 4.3 due to the P,CH, protons with couplings 2J(PH) = 10 Hz and ,J(PtH) = 44 Hz, typical of chelating dppm. The ,'P n.m.r. spectrum consists of a singlet at -51.4 p.p.m. with 'J(PtP) = 2 393 Hz, Table 1, only consistent with chelating dppm. Similar reactions occurred with other re...