Synthesis, molecular structure, and characterization in solution of a new series of inorganic and organometallic Co(III) Schiff base complexes

Abstract

A new series of inorganic and organometallic cobalt Schiff base complexes containing the tetradentate ligand tmsalen (4,4′,7,7′, tetramethylsalen) have been synthesized. They have been characterized by 1H NMR and UV–Vis spectroscopy and by ESI MS spectrometry, both in coordinating and non-coordinating solvents. Two inorganic complexes [Co(tmsalen)(L) 2]ClO 4, where L=py ( 2) and N-MeIm ( 3), two dimeric organometallic derivatives [RCo(tmsalen)] 2 (R=CH 3 ( 4) and CH 2CF 3 ( 7)) and one organometallic penta-coordinated species (R=i-Pr ( 6)) have been structurally characterized. It is noteworthy that the formation of organometallic dimeric and penta-coordinated species occurs even if the synthesis is carried out in presence of py. Solution data confirm the strong tendency to the penta-coordination of the complexes containing the most electron-donating alkyl groups, which maintain penta-coordination even in methanol.