Ruthenium Complexes with a Terminal Hydrazido Ligand. Synthesis, Spectroscopy, and X-ray Crystal Structure

Bis(1,1-diphenylhydrazido(1−))ruthenium(IV) porphyrins, [RuIV(Por)(NHNPh2)2] (Por = TPP, TTP, 4-Cl-TPP,
4-MeO-TPP), were prepared in ∼60% yields through the reaction of dioxoruthenium(VI) porphyrins, [RuVI(Por)O2], with 1,1-diphenylhydrazine in ethanol. This new type of ruthenium complex has been characterized by 1H
NMR, IR, UV−vis, and FABMS with elemental analysis. The crystal structure of [RuIV(TTP)(NHNPh2)2], which
reveals an η1-coordination mode for both hydrazido axial ligands, has been determined. The average Ru−NHNPh2
distance and Ru−N−N angle were found to be 1.911(3) Å and 141.1(3)°, respectively. The porphyrin ring exhibits
a ruffling distortion that is unprecedentedly large for ruthenium complexes with simple porphyrinato ligands
(such as TTP). This is probably due to the steric effect of the axial hydrazido(1−) ligands.