Survey Of Long d¹⁰–d¹⁰ Metallophilic Contacts in Four-Membered Rings of Ag(I) and Au(I) Supported by Carbene–Pyrazole Mixed Ligands

Abstract

The interesting case of long intramolecular d(10)-d(10) contacts has been studied through [Ag(4)L(2)](2+) and [Au(4)L(2)](2+) (L = 3,5-bis((N-methylimidazolyl)methyl)pyrazole) systems, showing interesting features gained by analysis of the electronic structure and the overall shielding tensor in the molecular domain, in terms of its components. The long intramolecular closed-shell separations are attributed to the population of the bonding, nonbonding, and antibonding combinations of the ns atomic shells in the [M(4)](4+) core, contrasting with that observed in systems with shorter d(10)-d(10) distances. This point allows to concludeb that separations shorter then the sum of the van der Waals radii (3.4 Å for Ag-Ag, and 3.2 Å for Au-Au) of the nucleus involved requires a net bonding population between ns and np atomic shells of the d(10) closed-shell centers. Moreover, [Au(4)L(2)](2+) exhibits an increased covalency observed for the enhanced charge-donation due to the stabilization of the ns and destabilization of the (n - 1)d driven by the relativistic effects. The magnetic response denotes a slight interaction between the closed-shell centers at distances in the range of their sum of van der Waals radii because the observed remote effect (or anisotropic effect) caused by each d(10) nucleus does not influence considerably the neighbor center. The analysis of δ in terms of its components allows to conclude that the [Au(4)L(2)](2+) system exhibits an increased magnetic response due to the increase in the number of the inner-electrons in comparison to [Ag(4)L(2)](2+).

Cyclic trinuclear copper(i), silver(i), and gold(i) complexes: a theoretical insight

“…6), describes the slight interaction between the closedshell centers due to the remote effect (or anisotropic effect) caused by each nucleus not considerably influencing the neighbor center. 21 This result agrees with the analysis of the population of the ns (Γ ns ) derived levels within the M 3 3+ core, leading to long d 10 -d 10 contacts. At the center of the ring the δ iso values (also denoted as NICS (0)) denote values of about −1.5 ppm along the pyrazolate series, whereas the value at the center of the M + -M + distance increases slightly, −1.5 ppm (1a) < −1.7 ppm (1b) < −3.6 ppm (1c).…”

“…Usually, d 10 -d 10 contacts exhibit distances shorter than the sum of the van der Waals radii of the involved centers, resulting in a situation which has been coined as a metallophilic interaction. In this respect, the ligand to metal donation results in the population of the ns-based levels of the closed-shell core, which has been described as a useful characteristic to denote both short or long d 10 -d 10 contacts, [21][22][23] where in the former case the bonding combinations are mainly populated leading to distances sizably shorter than the sum of the van der Waals radii, contributing to the metallophilic situation. The most common bridging ligands employed in CTCs are the anionic heterocycles with five members 24 such as pyrazolate, triazolate, imidazolate, and their substituted derivatives.…”

Bonding and properties of superatoms. Analogs to atoms and molecules and related concepts from superatomic clusters

“…Moreover, magnetic response properties have also been discussed in relation to coinage metal planar clusters denoting the relevant contribution of the core electrons from the heavy atoms, in the induced magnetic field given mainly in the diamagnetic term. This observation is required for further use of magnetic response properties in the characterization of aromatic properties in heavy‐element rings, which is even able to account for the intermetallic bonding features . Furthermore, mercury(II) species given by [Hg(C(CF 3 ) 2 ] 5 , have been discussed in literature …”

“…This observation is required for further use of magnetic response properties in the characterization of aromatic properties in heavy-element rings, which is even able to account for the intermetallic bonding features. [92,93] Furthermore, mercury(II) species given by [Hg(C(CF 3 ) 2 ] 5 , have been discussed in literature. [94,95] 4 | THIOLATE-PROTECTED GOLD CLUSTERS…”

Advances in bonding and properties of inorganic systems from relativistic calculations in Latin America

“…Usually, aurophilic interaction led to an Au(I)‐Au(I) separation lower than the sum of their van der Waals radii, with distances of about 3.2‐3.6 Å . The bonding picture obtained from relativistic calculations for both cases was conveniently named long‐ and short‐metallophilic contacts, respectively, by Guajardo Maturana, Ponce‐Vargas and Muñoz‐Castro . d 10 ‐d 10 distances of 2.7 and 3.3 Å were obtained from the comparison of [Ag 4 (Mes) 4 ] and [Au 5 (Mes) 5 ] (Mes = 2,4,6‐Me 3 C 6 H 2 ) and [Ag 4 L 2 ] 2+ and [Au 4 L 2 ] 2+ (L = 3,5‐bis([N‐methyl‐imidazolyl]‐methyl)pyrazole.…”