Structure and bonding of [(SIPr)AgX] (X = Cl, Br, I and OTf)

Abstract

A series of iso-structural complexes [(SIPr)AgX] (X = Cl, Br, I, OTf; SIPr = 1,3-bis(2,6-diisopropylphenyl)imidazolidene) were synthesised, including the first example of a N-heterocyclic carbene silver(I) complex containing an O-bound triflate. Bond Energy Dissociation and Natural Orbitals for Chemical Valence bond analyses (BEDA & ETS-NOCV) revealing a significant NHC → M σ-back-donation, which influences the stability and sigma-donicity of these complexes.

Theoretical NMR spectroscopy of N-heterocyclic carbenes and their metal complexes

“…For modeling electronic properties, the situation is more complex, since influences of the electronic structure of the catalyst on the catalytic behavior can have different origins [7]. In this scenario, it is not surprising that the number of electronic descriptors capable of rationalizing catalytic behavior (such as nucleophilicity and electrophilicity indexes or the Tolman electronic parameter [1,8,9]) is large and that specific computational tools are capable of capturing different aspects of catalysts. Among the available computational tools, the theoretical analysis of NMR properties is extremely powerful due to the possibility of directly correlating theoretical calculations with experimental measurements.…”

Vinyltrifluoroborate Complexes of Silver Supported by N‐Heterocyclic Carbenes

“…Indeed, structurally well authenticated, monomeric silver complexes of the type (NHC)AgX are relatively less common , . Search of Cambridge Structural Database show that (NHC)Ag(carboxylate) complexes are the better known monomeric (NHC)AgX systems involving oxygen based anions (X),, while the only structurally characterized example of (NHC)Ag with a nitrate anion ligand, is a tetramer, [( i PrIm)Ag(NO 3 )] 4 …”

“…Similar behavior has been reported for silver(I) triflate analogs. For example, attempted isolation of (IPr)AgOTf has resulted in a ligand exchange leading to the homoleptic [(IPr) 2 Ag][OTf], while the (SIPr)AgOTf is more stable and isolable as a monomeric species . Compounds 1 – 3 are good sources of [(NHC)Ag] + via the replacement of NO 3 – groups.…”

“…Considering the low stability of 4 in solution and the ability of different NHC ligands to stabilize monomeric (NHC)AgX species [e.g., as observed with (NHC)AgOTf], we have investigated the use of SIPr and an even more sterically demanding IPr* supporting ligands in silver vinyltrifluoroborate chemistry. Compounds (SIPr)Ag(CH 2 =CHBF 3 ) ( 6 ) and (IPr*)Ag(CH 2 =CHBF 3 ) ( 7 ) have been synthesized by treating (SIPr)AgNO 3 ( 2 ) and (IPr*)AgNO 3 ( 3 ), respectively, with potassium vinyltrifluoroborate in CH 2 Cl 2 at room temperature.…”

Orbital Decomposition of the Carbon Chemical Shielding Tensor in Gold(I) N‐Heterocyclic Carbene Complexes

“…NHC is not a pure σ ‐donor but may have π‐acceptor character, being entirely negligible {as found in [(NHC)AuCO] + } or accounting up to half of the σ ‐donor character {as found in [(NHC)AuCl]} . A more comprehensive overview of the chemistry of N‐heterocyclic carbenes is given in ref., and recently [(NHC)AgX] compounds were synthesized . The bonding properties of the carbene–Au bond (also Ag/Cu were considered) in [(NHC)AuCl] and metal‐biscarbenes have been investigated using an energy decomposition analysis.…”