TY - JOUR
T1 - Preparation and hydrosilylation activity of a molybdenum carbonyl complex that features a pentadentate bis(imino)pyridine ligand
AU - Pal, Raja
AU - Groy, Thomas L.
AU - Bowman, Amanda C.
AU - Trovitch, Ryan
PY - 2014/9/2
Y1 - 2014/9/2
N2 - Attempts to prepare low-valent molybdenum complexes that feature a pentadentate 2,6-bis(imino)pyridine (or pyridine diimine, PDI) chelate allowed for the isolation of two different products. Refluxing Mo(CO)6 with the pyridine-substituted PDI ligand, PyEtPDI, resulted in carbonyl ligand substitution and formation of the respective bis(ligand) compound ( PyEtPDI)2Mo (1). This complex was investigated by single-crystal X-ray diffraction, and density functional theory calculations indicated that 1 possesses a Mo(0) center that back-bonds into the π-orbitals of the unreduced PDI ligands. Heating an equimolar solution of Mo(CO) 6 and the phosphine-substituted PDI ligand, Ph2PPrPDI, to 120 °C allowed for the preparation of (Ph2PPrPDI)Mo(CO) (2), which is supported by a κ5-N,N,N,P,P-Ph2PPrPDI chelate. Notably, 1 and 2 have been found to catalyze the hydrosilylation of benzaldehyde at 90°C, and the optimization of 2-catalyzed aldehyde hydrosilylation at this temperature afforded turnover frequencies of up to 330 h-1. Considering additional experimental observations, the potential mechanism of 2-mediated carbonyl hydrosilylation is discussed.
AB - Attempts to prepare low-valent molybdenum complexes that feature a pentadentate 2,6-bis(imino)pyridine (or pyridine diimine, PDI) chelate allowed for the isolation of two different products. Refluxing Mo(CO)6 with the pyridine-substituted PDI ligand, PyEtPDI, resulted in carbonyl ligand substitution and formation of the respective bis(ligand) compound ( PyEtPDI)2Mo (1). This complex was investigated by single-crystal X-ray diffraction, and density functional theory calculations indicated that 1 possesses a Mo(0) center that back-bonds into the π-orbitals of the unreduced PDI ligands. Heating an equimolar solution of Mo(CO) 6 and the phosphine-substituted PDI ligand, Ph2PPrPDI, to 120 °C allowed for the preparation of (Ph2PPrPDI)Mo(CO) (2), which is supported by a κ5-N,N,N,P,P-Ph2PPrPDI chelate. Notably, 1 and 2 have been found to catalyze the hydrosilylation of benzaldehyde at 90°C, and the optimization of 2-catalyzed aldehyde hydrosilylation at this temperature afforded turnover frequencies of up to 330 h-1. Considering additional experimental observations, the potential mechanism of 2-mediated carbonyl hydrosilylation is discussed.
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U2 - 10.1021/ic501465v
DO - 10.1021/ic501465v
M3 - Article
AN - SCOPUS:84906859999
VL - 53
SP - 9357
EP - 9365
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 17
ER -