Bonding situation in isolable silver(I) carbonyl complexes of the Scorpionates

Abstract

The bonding situation of Ag(I)CO complexes having a Scorpionate ligand directly attached to the transition metal has been analyzed in detail by means of relativistic density functional theory calculations. To this end, different experimentally characterized complexes together with other representative species have been considered to rationalize the observed shift of the corresponding ν(CO) stretching frequencies and the influence of the substituents in the Scorpionate ligand. With the help of the energy decomposition analysis method combined with the natural orbital for chemical valence it is found that the main contribution to the bonding comes from the electrostatic attractions between the LAg(I) and CO fragments. Despite that, the LAg → CO π‐backdonation is also significant in these species as well as in related LCu(I)CO complexes.

Carbonyl and Isocyanide Complexes of Copper and Silver Supported by Fluorinated Poly(pyridyl)borates

“…Note that one of the reasons for investigating these Cu−CO and Ag−CO complexes 11, 13−15 is to probe the scorpionate ligand effects on the metal site using the CO stretch, and to compare the new poly(pyridyl)borate and better-known poly(pyrazolyl)borate systems. Computational analysis 30,99 100,101 Overall, the strength of the electrostatic attraction and the degree of π-backbonding between LM and CO fragments correlate well with the observed υ ̅ (CO), which gets higher with more weakly donating ligand support on a metal. Computational work on the above systems also shows that the copper complexes display stronger LCu → CO π-backdonation relative to their silver counterparts.…”

“…Note that one of the reasons for investigating these Cu–CO and Ag–CO complexes 11 , 13 – 15 is to probe the scorpionate ligand effects on the metal site using the CO stretch, and to compare the new poly­(pyridyl)­borate and better-known poly­(pyrazolyl)­borate systems. Computational analysis , of molecules such as [Ph 2 B­(3-(CF 3 )­Pz) 2 ]­Cu­(CO), [Ph 2 B­(3-(CH 3 )­Pz) 2 ]­Cu­(CO), [HB­(3,5-(CF 3 ) 2 Pz) 3 ]­Ag­(CO), and [MeB­(3-(Mes)­Pz) 3 ]­Ag­(CO) indicate that the LM and CO (L = scorpionate) is mainly electrostatic. Traditional σ-donor/π-acceptor interactions usually explained by the Dewar–Chatt–Duncanson model are also significant. , Overall, the strength of the electrostatic attraction and the degree of π-backbonding between LM and CO fragments correlate well with the observed υ̅(CO), which gets higher with more weakly donating ligand support on a metal.…”

Classical Gold Carbonyl Complexes in Tetrahedral and Trigonal‐Planar Settings

“…The CO stretching frequency of solid 5 and 6 in their IR spectra were observed at 2143 and 2092 cm −1 , respectively, indicating that the silver adduct shows the least amount of M→CO backbonding in this series of metal carbonyls consisting of 2 , 5 , and 6 . It is noteworthy that the relatively low ῡ (CO) value observed for 5 (which is same as that of the free CO) is not common as most silver−CO adducts are of the non‐classical metal carbonyl type with ῡ (CO) >2143 cm −1 [58–60] . The [MeB(3‐(Mes)Pz) 3 ]Ag(CO) is a rare exception with ῡ (CO) observed at 2025 cm −1 [44] .…”

“…It is noteworthy that the relatively low ῡ(CO) value observed for 5 (which is same as that of the free CO) is not common as most silverÀ CO adducts are of the non-classical metal carbonyl type with ῡ(CO) > 2143 cm À 1 . [58][59][60] The [MeB(3-(Mes)Pz) 3 ]Ag(CO) is a rare exception with ῡ(CO) observed at 2025 cm À 1 . [44] In addition, gold complex 2 has a lower ῡ(CO) value compared to that of 6.…”

Effects of Electron‐Withdrawing and ‐Donating Substituents in N‐Donor Scorpionate Ligands and the Metal 5 f/4 f Orbitals on Am(III)/Eu(III) Complexation and Separation

“…Stuhl and co‐workers [16] synthesized the complexes of tris(pyrazolyl)methane scorpionate ligand with Mg and determined the cone angles of the magnesium complexes. Fernández and co‐workers [17] analyzed in detail the bonding situation of silver(I) carbonyl complexes of the scorpionates using the relativistic density functional calculation. Tzegai and co‐workers [18] synthesized bis(4‐carboxylpyrazol‐1‐yl)acetic acid (H 3 bcpza) as a scorpionate ligand for improving the water solubility of the complexes.…”