The mono(guanidinato) complex Cp(guan)ZrCl2 (1; guan = η2-(iPrN)2C(NMe2)) was prepared by treatment of CpZrCl3 (Cp = η5-C5H5) with the in situ generated lithium guanidinate salt 2. The dimethylamino group of 1 resists quaternization by alkylating and silylating reagents. Complex 1 undergoes ligand redistribution when treated with 2 equiv of MeLi, but reaction with 2 equiv of MeMgCl affords the dimethyl derivative Cp(guan)ZrMe2 (3). Insertion of 2 equiv of diisopropylcarbodiimide into the Zr−N bonds of (Me2N)2ZrCl2(THF)2 produces the bis(guanidinato)zirconium dichloride complex (guan)2ZrCl2 (4). Alkylation of 4 with 2 equiv of MeLi or PhCH2MgCl affords the dialkyl derivatives (guan)2ZrMe2 (5) and (guan)2Zr(CH2Ph)2 (6), respectively. Variable-temperature NMR experiments on 6 reveal a limiting C 2-symmetric solution structure at 253 K. Complex 5 undergoes reaction with electrophiles (Me3SiOTf (OTf = OSO2CF3), B(C6F5)3, [Ph3C][B(C6F5)4]) to yield stable products of methide abstraction:  neutral complexes (guan)2Zr(OTf)2 (7) and (guan)2Zr(Me)OTf (8), base-free cationic alkyl salts [(guan)2ZrMe][MeB(C6F5)3] (9) and [(guan)2ZrMe][B(C6F5)4] (10), and the dinuclear methyl-bridged cation [((guan)2ZrMe)2-μ-Me][B(C6F5)4] (11). Complexes 1, 4−7, and 11 have been characterized by X-ray diffraction. Dinuclear cation 11 exhibits bridge−terminal methyl exchange on the NMR time scale at room temperature, with decoalescence observed at 224 K. Dibenzyl complex 6 undergoes reaction with [Ph3C][B(C6F5)4] in CH2Cl2, yielding the cationic benzyl complex [(guan)2Zr(CH2Ph)][B(C6F5)4] (15). Spectroscopic data imply that the benzyl ligand of 15 adopts an undistorted monodentate coordination mode. Complexes 4, 5, and 10 were found to have low to moderate activities for the polymerization of α-olefins.

Monomeric thiosalicylaldiminate complexes of rhodium(I) and iridium(I) were prepared by ligand transfer from the homoleptic zinc(II) species. In the presence of strongly donating ligands, the iridium complexes undergo insertion of the metal into the imine carbon−hydrogen bond. Thiophenoxyketimines were prepared by nontemplated reaction of o-mercaptoacetophenone with anilines and were complexed with rhodium(I), iridium(I), nickel(II), and platinum(II). X-ray crystallographic studies showed that while the thiosalicylaldiminate complexes display planar ligand conformations, those of the thiophenoxyketiminates are strongly distorted. Results of a computational study predicted that all synthetically accessible thiophenoxyketiminates will display distorted geometries.