N-Heterocyclic carbene and cyclic (alkyl)(amino)carbene ligated half-sandwich complexes of chromium() and chromium()

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 52; no. 37; pp. 13244 - 13257
• Main Authors: Horrer, Günther, Luff, Martin S, Radius, Udo
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 26.09.2023
• Subjects: Carbenes; Chromium; Metallography; Quantum chemistry
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d3dt02123h

The synthesis and characterization of a series of Cr( ii ) N-Heterocyclic Carbene (NHC) complexes of the type [{Cr(NHC)Cl(μ-Cl)} 2 ] and [(Cyp)Cr(NHC)X] (Cyp = η 5 -C 5 H 5 , cyclopentadienyl; η 5 -C 5 Me 5 , pentamethylcyclopentadienyl; X = Cl, η 3 -C 3 H 5 ; NHC = IMe Me , IiPr Me , IMes, IDipp) as well as the cyclic (alkyl)(amino)carbene cAAC Me ligated complexes [(η 5 -C 5 H 5 )Cr(cAAC Me )X] (X = Cl, NPh 2 ), [(η 5 -C 9 H 7 )Cr(cAAC Me )Cl] (C 9 H 7 = Ind, indenyl) and [(η 5 -C 13 H 9 )Cr(cAAC Me )Cl] (C 13 H 9 = Fl, fluorenyl) are reported. The reduction of [(η 5 -C 5 Me 5 )Cr(IMe Me )Cl] with KC 8 in the presence of CO afforded the NHC ligated Cr( i ) metallo-radical [(η 5 -C 5 Me 5 )Cr(IMe Me )(CO) 2 ]. Quantum chemical calculations performed on [(η 5 -C 5 Me 5 )Cr(IMe Me )(CO) 2 ] confirm for this complex a predominantly chromium centered radical. Cr( ii ) NHC complexes of the type [{CrCl(L)(μ-Cl)} 2 ], [(η 5 -C 5 R 5 )Cr(NHC)(X)] (η 5 -C 5 R 5 = C 5 H 5 , C 5 Me 5 , C 9 H 7 , C 13 H 9 ; X = Cl, η 3 -allyl, NPh 2 ; NHC = IMe Me , IiPr Me , IMes, IDipp, cAAC Me ) and the Cr( i ) metalloradical [(η 5 -C 5 Me 5 )Cr(CO) 2 (IMe Me )] are reported.