Molybdenum complexes of chiral C2-symmetric picchxn-type ligands: Synthesis, characterization, and structural studies

Abstract

A series of molybdenum complexes based on chiral C 2-symmetricpicchxn-type ligands (N 4 ligands, defined as trans-N,N'-bis(heterocycl-2-ylmethyl)-1,2-diaminocyclohexanes) has been synthesized and characterized. Reported and novel picchxn-type ligands form (κ 3-N 4)Mo(CO) 3 , [(κ 4-N 4)Mo(NO)(CO)]PF 6 , and [(κ 4-N 4)Mo(NO)X]PF 6 (X = Br, I) compounds. Multiple tridentate (κ 3) and tetradentate (κ 4) ligand configurations were observed, and the favored κ 4 configuration was found to vary with N 4 heterocycle identity. Heterocycle variation allowed for directed modification of the molybdenum electronic characteristics, but none of the studied {(κ 4-N 4)Mo(NO)} + fragments was found to be a suitable π-base for dearomatization chemistry. The crystal structures of eight molybdenum complexes with picchxn-type ligands were determined.