Conversion of Hydroxo-Bridged Diplatinum(II) Complexes to Amido-Bridged Diplatinum(II) Complexes. X-ray Crystal Structure of trans-[Pt2(μ-NH2)2(Ph2PO)2(PPh2Me)2]CH3CH2OH

The amido-bridged diplatinum complexes cis- and trans-[Pt2(μ-NH2)2(POPh2)2(PMePh2)2] (1a,b) as a mixture of isomers has been made by treating [PtCl2(dppm-P,P′] with sodium hydroxide in aqueous ammonia or by treatment of [Pt2(μ-OH)2- (POPh2)2(PMePh2)2] with aqueous ammonia. The mixture 1a,b has been characterized by 1H, 31P(1H), and 15N{1H} NMR spectroscopy, and the X-ray crystal structure of the trans isomer la has been determined (monoclinic, C2/c, a = 25.576 (10) Å, b = 14.609 (4) Å, c = 26.988 (10) Å, β = 102.73 (4)°, R = 0.045 for 3478 observed reflections (I/σ(I) ⩾ 3.0)). The [Pt2N2] ring has a Pt-N bond of 2.114 (7) Å and a dihedral angle of 44 (1)° between the Pt coordination planes. Addition of aqueous ammonia to [Pt2(μ-OH)2(PR3)4]2+ complexes gives the corresponding [Pt2(μ-NH2)2(PR3)4]2+ complexes. © 1991, American Chemical Society. All rights reserved.