A dinuclear platinum(II) complex with hydrazine and chloro bridges: (NPr4n)[PtCl2(mu-Cl)(mu-N2H2)PtCl2]

The dinuclear platinum(II) complex with a simple hydrazine bridge, (NPr4n)( 2)[PtCl3(mu-N2H4)PtCl3], undergoes spontaneous cyclization in ethanol, yiel ding (NPr4n)[PtCl2(mu-Cl)(mu-N2H4)PtCl2]. The novel cyclic compound was ide ntified by means of microanalysis, UV absorption, and H-1 and Pt-195 NMR sp ectroscopy. A conformational analysis using density functional calculations indicated that the N-Pt-Cl-Pt-N five-membered ring assumes a twisted confo rmation of C-2 symmetry; the energy barrier separating the two enantiomeric forms was calculated to be similar to 10 kcal mol(-1), which corresponds t o an approximate interconversion rate of 2 x 10(5) s(-1) at 300 K. (C) 1999 Elsevier Science S.A. All rights reserved.