Reactions of [Rh(Tp*)(PPh3)2] (Tp* = hydrotris(3,5-dimethylpyrazolyl)-borate) involving fragmentation or loss of Tp*.: Structures of [Rh(Cl)2(H)(PPh3)2(pz*)], [(PPh3)2Rh(μ-SC6F5)2Rh (SC6F5)(H)(PPh3)(pz*)] (pz*=3,5-dimethylpyrazole) and [{Rh(Cl)2(PPh3)2}2Hg]

The complex [Rh(Tp*)(PPh3)(2)] reacts with dichloromethane to give [Rh(Cl)(H)(2)(PPh3)(2)(pz*)] (1) and [Rh(Cl)(2)(H)(PPh3)(2)(pz*)] (2), with C6F5SH to give [(PPh3)(2)Rh(mu-SC6F5)(2)Rh(SC6F5)(H)(PPh3)(pz*)] (3) and with HgCl2 to give [{Rh(Cl)(2)(PPh3)(2))(2)Hg] (4), all under mild conditions. The crystal structures show that 2 has a slightly distorted octahedral geometry, 3 has approximately square planar Rh(I) and octahedral Rh(III) geometries, with an angle of 160.7degrees between the two RhS2 planes and 4 has rhodium with a square pyramidal geometry where mercury occupies a position at the apex of the pyramid; the Rh-Hg-Rh geometry is linear and, with respect to the Rh-Hg-Rh axis, the ligands (Cl, PPh3) on one rhodium are offset by approximately 42degrees relative to their counterparts on the second rhodium. In 2 an intramolecular hydrogen bond exists between the pyrazole NH and one of the chloride ligands. Structure 4 is unusual in that it contains an unsupported mercury bridge. (C) 2003 Elsevier Ltd. All rights reserved.