Strong Closed-Shell Interactions in Inorganic Chemistry.

Recently accumulated experimental evidence for aurophilic interactions in and between molecular gold(I) compounds and the results of pertinent theoretical calculations are reviewed for the period from 2007 to mid-2011. The influence of the intra- and intermolecular bonding contacts between the closed-shell metal centres, Au–Au, on the molecular and crystal structures, and the consequences of these effects for the chemical and physical properties of gold compounds are summarized for the various classes of mono- and polynuclear systems. The literature survey builds on the contents of previous reviews and relates new experimental and theoretical findings to earlier observations (353 references).

Aurophilic interactions as a subject of current research: an up-date

There is now compelling experimental evidence for the existence of specific intra- and intermolecular bonding between seemingly closed-shell gold(I) centers (5d10) which manifests itself in all areas of gold chemistry. This “aurophilic interaction”, which had not been predicted by conventional valence theory, was found to be associated with binding energies in some cases exceeding even those of strong hydrogen bonds and therefore to be highly significant in co-determining molecular structure and dynamics. In high-level theoretical treatments the attraction is rationalized as a “super van der Waals bonding” based on particularly strong relativistic, dispersion and correlation effects (critical review, 265 references).

A briefing on aurophilicity.

A Calculation of Atomic Structures. By D. R. Hartree Pp. xiii, 181. 40s. 1957. (Wiley, New York)

Relatively little attention has been paid to metal ions with the nd[sup 10] and nd[sup 10](n+1)s[sup 2] (i.e., [open quotes]s[sup 2][close quotes]) configurations. In combination with various anionic and neutral ligands, these metal ions form a wide variety of cluster compounds, some of which have been known to be luminescent when irradiated with ultraviolet light. Prominent examples of this family are cuprous iodide clusters such as Cu[sub 4]I[sub 4]-(py)[sub 4] (1, py = pyridine), which shows [open quotes]luminescence thermochromism[close quotes]; that is, they display bright emissions with colors markedly dependent on the temperature. Here the authors present an overview of recent studies carried out both independently and jointly in the authors' laboratories focusing upon the remarkably rich, but relatively unexplored, photochemical and photophysical properties of various tetra-and hexanuclear d[sup 10] and s[sup 2] metal ion clusters in solution. 74 refs., 4 figs., 2 tabs.

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Photochemical and photophysical properties of tetranuclear and hexanuclear clusters of metals with d10 and s2 electronic configurations

Copper(I)-copper(I) interactions. Bonding relationships in d10-d10 systems

An “average state” of a molecule is defined by distributing the electrons equally among the valence orbitals of a minimal basis set Hartree-Fock calculation. The resulting eigenvalues, called tempered orbital energies, behave much more like the Mulliken-Walsh diagram energies or extended Huckel eigenvalues than do the Hartree-Fock canonical orbital energies.

Tempered orbital energies in SCF MO calculations and their relation to the ordinate in Mulliken-Walsh correlation diagrams and extended Hückel orbital energies

A new formulation of “level-shifting” method is presented, which provides a more economical procedure for computations.

Prem K. Mehrotra

Papers

Copper(I)-copper(I) interactions. Bonding relationships in d10-d10 systems

Tempered orbital energies in SCF MO calculations and their relation to the ordinate in Mulliken-Walsh correlation diagrams and extended Hückel orbital energies

On the “level-shifting” method for converging hartree-fock wave functions