Preparation and reactivity of penta- and tetracoordinate platinum(ii) hydride complexes with P(OEt)3 and PPh(OEt)2 phosphite ligands

The pentacoordinate [PtH{P(OEt)3}4]BF4 (1) hydride complex was prepared by allowing the tetrakis(phosphite) Pt{P(OEt)3}4 to react with HBF4.Et2O at -80 degrees C. Depending on the nature of the acid used, however, the protonation of the related Pt{PPh(OEt)2}4 complex yielded the pentacoordinate [PtH{PPh(OEt)2}4]BF4 (3) or the tetracoordinate [PtH{PPh(OEt)2}3]Y (4) [Y = BF4- (a), CF3SO3- (b), Cl- (c)] derivatives. Neutral PtHClP2 (7,8) [P = P(OEt)3, PPh(OEt)2] hydride complexes were prepared by allowing PtCl2P2 to react with NaBH4 in CH3CN. The tetrakis(phosphite)[Pt{P(OEt)3}4](BF4)2 (2) derivative was also synthesised and then characterised spectroscopically and by an X-ray crystal structure determination. Reactivity with aryldiazonium cations of all the hydrides was investigated and found to proceed only with the PtHClP2 complex to yield the aryldiazene [PtCl(ArN=NH)P2]BF4[P = PPh(OEt)2] derivative. The hydrazine [PtCl(NH2NH2){PPh(OEt)2}2]BPh4 complex was also prepared by allowing PtHClP2 to react first with AgCF3SO3 and then with hydrazine.