TY - JOUR
T1 - Cationic iron(II) complexes of the mixed cyclopentadienyl (Cp) and the N-heterocyclic carbene (NHC) ligands as effective precatalysts for the hydrosilylation of carbonyl compounds
AU - Kumar, Dharmendra
AU - Prakasham, A. P.
AU - Bheeter, Linus Paulin
AU - Sortais, Jean Baptiste
AU - Gangwar, Manoj
AU - Roisnel, Thierry
AU - Kalita, Alok Ch
AU - Darcel, Christophe
AU - Ghosh, Prasenjit
N1 - Funding Information:
PG is grateful to the Sophisticated Analytical Instrument Facility at IIT Bombay, India, for the characterization data and thanks Prof. R. Murugavel for the use of his Single Crystal X-ray Diffraction Facility established through a DAE-SRC Outstanding Investigator Award. DK thanks CSIR-UGC, New Delhi, for research fellowship.
Funding Information:
We thank Indo-French Centre for the Promotion of Advanced Research – IFCPAR (Project No: 4605-B ), New Delhi, for financial support of this research.
Funding Information:
CD and JBS thank the French “ Ministère de l’Enseignement Supérieur et de la Recherche ” and the CNRS for financial support. LPB thanks IFCPAR for a PhD grant.
PY - 2014/7/15
Y1 - 2014/7/15
N2 - A series of iron(II) complexes of N-heterocyclic carbene ligands was synthesized and fully structurally characterized. Specifically, the benzimidazole based {Cp[1,3-di-R-benzimidazol-2-ylidene]-Fe(CO)2}I [R = Et (1b), i-Pr (2b) and n-Bu (3b)] and the imidazole based {Cp[1-benzyl-3-R-imidazol-2-ylidene]Fe(CO)2}PF6 [R = Me (4b) and Et (5b)] type of complexes were synthesized from their respective benzimidazolium iodide (1-3)a and their imidazolium hexafluorophosphate (4-5)a salts by the reaction with CpFe(CO)2I in the presence of MN(SiMe 3)2 (M = Li or K) as a base. The molecular structures of the (1-5)b complexes reveal that the metal center display a conventional piano stool structure. More importantly, the (1-5)b complexes, when irradiated with visible light, effectively catalyzed the hydrosilylation reaction of carbonyl compounds namely, of the aldehyde and ketone substrates, using organosilane reagents. Specifically, the (1-5)b complexes performed the hydrosilylation of a representative benzaldehyde substrate using phenylsilane in ambient conditions at 30 °C while that of the representative acetophenone substrate at a more elevated temperature of 70°C. The benzimidazole derived complexes (1-3)b displayed superior activity than the imidazole derived (4-5)b complexes.
AB - A series of iron(II) complexes of N-heterocyclic carbene ligands was synthesized and fully structurally characterized. Specifically, the benzimidazole based {Cp[1,3-di-R-benzimidazol-2-ylidene]-Fe(CO)2}I [R = Et (1b), i-Pr (2b) and n-Bu (3b)] and the imidazole based {Cp[1-benzyl-3-R-imidazol-2-ylidene]Fe(CO)2}PF6 [R = Me (4b) and Et (5b)] type of complexes were synthesized from their respective benzimidazolium iodide (1-3)a and their imidazolium hexafluorophosphate (4-5)a salts by the reaction with CpFe(CO)2I in the presence of MN(SiMe 3)2 (M = Li or K) as a base. The molecular structures of the (1-5)b complexes reveal that the metal center display a conventional piano stool structure. More importantly, the (1-5)b complexes, when irradiated with visible light, effectively catalyzed the hydrosilylation reaction of carbonyl compounds namely, of the aldehyde and ketone substrates, using organosilane reagents. Specifically, the (1-5)b complexes performed the hydrosilylation of a representative benzaldehyde substrate using phenylsilane in ambient conditions at 30 °C while that of the representative acetophenone substrate at a more elevated temperature of 70°C. The benzimidazole derived complexes (1-3)b displayed superior activity than the imidazole derived (4-5)b complexes.
KW - Benzimidazole
KW - Hydrosilylation
KW - Imidazole
KW - Iron
KW - NHC ligands
UR - http://www.scopus.com/inward/record.url?scp=84899674953&partnerID=8YFLogxK
U2 - 10.1016/j.jorganchem.2014.03.016
DO - 10.1016/j.jorganchem.2014.03.016
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AN - SCOPUS:84899674953
SN - 0022-328X
VL - 762
SP - 81
EP - 87
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
ER -