Group 11 Metal Complexes of N-Heterocyclic Carbene Ligands: Nature of the Metal-Carbene Bond

The silver, copper and gold complexes of tripodal N-heterocyclic carbene (NHC) ligand, 1,1,1-tris[(3-methylimidazol-1-yl-2-ylidene)methyl]ethane were prepd. and characterized. The silver complex of the title ligand, TIMEMe was prepd. by reaction of [H3TIMEMe][PF6]3 with Ag2O, which afforded trinuclear bis-carbene silver complex [(TIMEMe)2Ag3](PF6)3 (3). Reaction of 3 with CuBr or (Me2S)2AuCl yielded the corresponding D3-sym. copper(I) and gold(I) complexes [(TIMEMe)2Cu3](PF6)3 (4) and [(TIMEMe)2Au3](PF6)3 (5). Single-crystal x-ray diffraction, spectroscopic, and computational studies of this series of metal NHC complexes are described. The group 11 metal complexes of the TIMEMe ligand exhibit isostructural geometries, with three metal ions bridging two of the TIMEMe ligands. Each metal ion is linearly coordinated to two carbene centers, with each of the carbenoid carbons stemming from a different ligand. Overall, the mols. possess D3 symmetry. The electronic structure of these newly prepd. compds. was elucidated with the aid of DFT calcns. In contrast to the common assumption that NHCs are pure sigma-donor ligands, the orbital energy calcns. for complexes 3-5, bis(1,3-di-tert-butylimidazol-2-ylidene)palladium (6), model D2h complexes bis(1,3-dimethylimidazol-2-ylidene)silver, -copper, and -gold (8-10, resp.) reveal the existence of both sigma- and pi-type interactions between the metal ions and the carbenoid carbons. In these diaminocarbene models the contribution of pi-back-bonding interactions is approx. 15-30% of the overall orbital interaction energy of the complexes. [on SciFinder (R)]


Published in:
Organometallics, 23, 4, 755-764
Year:
2004
Keywords:
Density functional theory (ADF; DFT geometry ; orbital energy and pi-bonding of copper ; silver and gold trinuclear complexes with tridentate ; imidazolylidene ligand); Energy level (DFT geometry ; orbital energy and pi-bonding of copper ; silver and gold trinuclear complexes with tridentate ; imidazolylidene ligand); Pi bond (back-; DFT calcn. of ; pi-bonding energy of copper ; silver and gold trinuclear complexes with tridentate ; imidazolylidene ligand); Organometallic compounds Role: PRP ; (Properties) ; SPN (Synthetic preparation) ; PREP (Preparation) (carbene complexes ; Group IB metal complexes; prepn. ; structure and DFT geometry and orbital energy of copper ; silver and gold trinuclear complexes with tridentate ; imidazolylidene ligand); Group IB element complexes Role: ; PRP (Properties) ; SPN (Synthetic preparation) ; PREP (Preparation) (carbene complexes; prepn. ; structure and DFT geometry and orbital energy of copper ; silver and gold trinuclear complexes with tridentate ; imidazolylidene ligand); Double bond (carbon-copper ; carbon-silver ; carbon-gold; DFT calcn. of pi-bonding energy of copper ; silver and gold trinuclear complexes with tridentate ; imidazolylidene ligand); Carbene complexes Role: PRP ; (Properties) ; SPN (Synthetic preparation) ; PREP (Preparation) (metal complexes ; Group IB metal complexes; prepn. ; structure and DFT geometry and orbital energy of copper ; silver and gold trinuclear complexes with tridentate ; imidazolylidene ligand); Heterocyclic compounds Role: PRP ; (Properties) ; RCT (Reactant) ; SPN (Synthetic preparation) ; PREP (Preparation) ; RACT (Reactant or reagent) (nitrogen ; five-membered ; imidazoles ; Group IB metal complexes; prepn. ; structure and DFT geometry and bonding energy of copper ; silver and gold trinuclear complexes with tridentate ; imidazolylidene ligand); Crystal structure; Molecular ; structure (of bridging trinuclear copper and gold ; tris-imidazolylidene complexes); Molecular structure ; (optimized; DFT geometry and orbital energy of copper ; silver and gold trinuclear complexes with tridentate ; imidazolylidene ligand) ; copper silver gold dicarbene imidazolylidene trinuclear ; bridging complex prepn; optimized geometry trinuclear copper ; silver gold bridging imidazolylidene; orbital energy ; trinuclear copper silver gold bridging imidazolylidene; DFT ; ADF geometry orbital energy trinuclear bridging ; imidazolylidene complex; carbene imidazolylidene pi bonding ; copper silver gold trinuclear complex; crystal structure ; trinuclear copper silver gold bridging imidazolylidene; mol ; structure trinuclear copper silver gold bridging imidazolylidene
Note:
CAN 140:235833 29-9 Organometallic and Organometalloidal Compounds Department of Chemistry and Biochemistry,University of California,La Jolla,CA,USA. Journal 0276-7333 written in English. 616-47-7 (1-Methyl-1H-imidazole) Role: RCT (Reactant), RACT (Reactant or reagent) (alkylation, quaternization; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand); 60111-68-4P (1,1,1-Tris(bromomethyl)ethane) Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (amination, quaternization; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand); 501086-84-6P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (anion exchange; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand); 2387-43-1P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (bromination; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand); 501086-86-8P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (complexation; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand); 666846-77-1P; 666846-79-3P Role: PRP (Properties), SPN (Synthetic preparation), PREP (Preparation) (crystal structure, optimized geometry, orbital energy; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand); 77-85-0 (1,1,1-Tris(hydroxymethyl)ethane) Role: RCT (Reactant), RACT (Reactant or reagent) (esterification; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand); 52356-52-2 (1,3-Dimethylimidazol-2-ylidene); 164172-45-6; 177283-33-9; 199447-45-5; 478081-86-6 Role: FMU (Formation, unclassified), PRP (Properties), FORM (Formation, nonpreparative) (optimized geometry, orbital energy; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand); 501086-88-0P Role: PRP (Properties), RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (transmetalation, optimized geometry, orbital energy; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand); 29892-37-3 (Chloro(dimethyl sulfide)gold) Role: RCT (Reactant), RACT (Reactant or reagent) (transmetalation; prepn., structure and DFT geometry and bonding energy of copper, silver and gold trinuclear complexes with tridentate imidazolylidene ligand)
Laboratories:




 Record created 2007-12-17, last modified 2018-07-07


Rate this document:

Rate this document:
1
2
3
 
(Not yet reviewed)