Reactions of molybdenum pentachloride with oxygen and nitrogen donor ligands

The interactions of molybdenum pentachloride (1) with a variety of organic compounds were studied in dichloromethane and the metal products were isolated in the solid state. The 3:1 molar reactions of 1 with OCRR' (R = R' = Ph; R = H, R' = 2-C6H4Me) afforded the complexes Mo(O)Cl-3(OCRR')(2) (R = R' = Ph, 2a; R = H, R' = 2-C6H4Me, 2b) in high yields. Compound Mo(O)Cl-3[O(CH)(3)CC(O)CH3], 3, was isolated in 35% yield from 1 and 2-acetylfuran. The 1:1 reaction of 1 with phenazine (C12H8N2) 1 resulted in the formation of MoCl5(C12H8N2), 4; the oxydo-chloride derivative Mo(O)Cl-3[kappa(1)(N)-Cl2H8N2], 5, was prepared straightforwardly by addition of phenazine to Mo(O)Cl-3, formed in situ upon treatment of 1 with tetrahydrofuran. The addition of a twofold excess of Me2NCH2CH2CO2Me to 1 afforded MoCl4[kappa(1)(N)-Me2NCH2 CH2CO2Me](2), 6, in 72% yield. The reaction of 1 with MeO2CC CCO2Me led to a mixture of inseparable products: Mo(O)Cl-3(kappa(1)-MeO2CC CCO2Me)(2), 7a, MoCl5(kappa(1)-MeO2CC CCO2Me), 7b, and MoCl4(kappa(1)-MeO2 CC CCO2Me)(2), 7c, were recognized by combined EPR/DFT investigation. Analogous DFT/EPR studies were performed on 2b and 4. The X-ray structures of 2a, 3 and 5 were determined; the X-ray structure of 5 represents a rare example of crystallographically-characterized pentacoordinated Mo(V) neutral complex. (C) 2013 Elsevier Ltd. All rights reserved.