STEREOCHEMISTRY OF TETRADENTATE SCHIFF BASE COMPLEXES OF COBALT(2)

A homologous series of cobalt(II) complexes with N,N’-bis(salicylidene)polymethylenediamine ligands, HOC6H4CH=N(CH2)nN=CHC6H4OH, where n = 3–6, has been prepared and characterized. Spectral and magnetic properties indicate that the anhydrous complexes with n = 4–6 are pseudo-tetrahedral. The anhydrous trimethylene complex is high spin but does not possess spectral properties similar to the higher members of the series. This is interpreted by assuming a flattened tetrahedral structure for the trimethylene complex, but a weak association leading to a dimeric structure with each cobalt ostensibly five-coordinate may not be ruled out. Mass spectrometric determinations of molecular weights provide evidence for the monomeric nature of the series of complexes. © 1969, American Chemical Society. All rights reserved.