Topological Analysis of Ag–Ag and Ag–N Interactions in Silver Amidinate Precursor Complexes of Silver Nanoparticles

Abstract

A series of silver-amidinate complexes is studied both experimentally and theoretically, in order to investigate the role of the precursor complex in the control of the synthesis of silver nanoparticles via an organometallic route. The replacement of the methyl substituent of the central carbon atom of the amidinate anion by a n-butyl group, allows for the crystallization of a tetranuclear silver-amidinate complex 3 instead of a mixture of di-and trinuclear silver-amidinate complexes 1 and 2, as obtained with a methyl substituent. The relative stabilities and dissociation schemes of various isomeric arrangements of silver atoms in 3 are investigated at the computational DFT level of calculation, depending on the substituents of the amidinate ligand. A tetranuclear silver-amidinate complex 4, exhibiting a diamond-like arrangement of the four silver atoms is also considered. Ag-N bonds and argentophilic Ag-Ag interactions are finely characterized using ELF and QTAIM topological analyses, and compared over the series of the related di, tri and tetranuclear silver-amidinate complexes 1-4. In contrast to the Ag-N dative bonds very similar over the series, argentophilic Ag-Ag interactions of various strengths and covalence degree are characterized for complexes 1-4. This gives insight into the role of the amidinate substituents on the nuclearity and intramolecular chemical bonding of the silver-amidinate precursors, required for the synthesis of dedicated AgNPs with chemically well-defined surfaces.

Coordination of Ethylamine on Small Silver Clusters: Structural and Topological (ELF, QTAIM) Analyses

“…QTAIM Atomic Charges q X and Charges Variation Δq X (in e) of N and C Atoms in the EA Molecule during the Coordination of EA on Ag n Clusters (2 nickel-triflate 22 or metallophilic interactions. 21,23 However, they might be anticipated to be less reliable for studying stronger dative bonds. It is noticeable however that a very good agreement between E int values of Au−PPh 3 bonds and the corresponding calculated dissociation energies were reported.…”

“…21 ELF and QTAIM descriptors, allowing to discriminate between ionic, weakly covalent, 22 and dative (also known as a coordinate bond) Ag−N bonds and describing finely the metallic Ag−Ag bonds, have already been successfully used to characterize the bonding and bond strength in some silver precursor complexes and in small silver clusters. 23 The paper is organized as follows. After a brief description of the computational methods used, the structure and the relative stability of 2D or 3D Ag n clusters are studied together with the charge distribution, in the absence and presence of one amine ligand.…”

QTAIM and ELF topological analyses of zinc-amido complexes

“…In contrast to the above QTAIM analysis, the ELF description makes therefore a clear distinction between two components of the Zn-Nt bond. The ELF descriptors of V(Zn, Nt)a attractors are analogous to those previously reported for the Cu-N dative bond in copper-imidazole complexes [21], or for the dative Ag-N bond in silver-amidinate complexes [22] exhibiting a strong ionic character, suggesting a significant contribution of the zwitterionic mesomeric form Zn + < -:N: − . However, in contrast to these reported complexes, there is no remaining monosynaptic ELF V(N) basin, which might be related to a lone pair of the nitrogen atom.…”

Interaction between organic molecules and a gold nanoparticle: a quantum chemical topological analysis

“…Though the contribution is small, but it is still non-negligible, and it demonstrates the possibilities of the overlapping of the LUMO of ligands and HOMO of Au 79 , which results in stronger interactions. [53,54]…”