An Update on Multiple Bonding between Heavier Main Group Elements: The Importance of Pauli Repulsion, Charge-Shift Character, and London Dispersion Force Effects

Abstract

An update on some recent developments in the bonding of compounds with multiple bonds between heavier main group elements is the major theme of this review. A brief historical summary of the field is given in the Introduction. This is followed by a discussion of the major factors affecting the multiple bonding between these elements and the approaches used in the interpretation of that bonding. This organizational format follows that used in two earlier comprehensive reviews covering the area. However, this review is not a comprehensive one and it concerns compounds with homonuclear multiple bonds only. It emphasizes two new themes which involve London dispersion force (LDF) energies and charge-shift (CS) effects that were not treated in the earlier reviews. Although LDF effects are always present in molecular species, it is now clear they can be of decisive importance in the stability of the multiple-bonded compounds, especially those where the multiple bond is weak.

Bridged Aromatic Oxo‐ and Thioethers with Intense Emission in Solution and the Solid State

“…For the oxygen atoms, the 2s orbital has only one radial node, so its radial distribution function (RDF) peaks farther away from the nucleus than in the case of 1s counterpart, whereas the 2p orbitals have no radial nodes and hence their RDF peak relatively close to the 2s function [21] . Despite their energy gaps, this formally supports potential sp hybridization and bonding angles above 100°.…”

Gallium Ligand Coordinated Group 15 Compounds (LGa−ECp', L=(CHNMe)2CH, E=N − Bi, Cp'=η1‐C5H5): Changeover from Electron‐Sharing to Donor‐Acceptor σ‐Interaction

“…[4] Insights from these initial findings, the numerous multiply bonded heavier main group compounds have been synthesized. [5][6][7][8][9][10][11][12][13][14][15][16][17][18] The classical 2c-2e bonding concepts have been revoked, and the dative bonding concepts, as in transition metal compounds, is introduced to explain unconventional structures in these compounds. [5,6,9] Among the multiply bonded heavier main group elements, the derivatives of group 13 and group 15 elements of the type RMER' (M = group 13 element and E = group 15 element) have attracted increasing attention because of their high reactivity due to the presence of Lewis acidic and Lewis basic sites in the same molecule.…”

Noncovalent Intra‐ and Intermolecular Interactions in Peri‐Substituted Pnicta Naphthalene and Acenaphthalene Complexes

“…Yield 60 %. 1 H NMR (CD 2 Cl 2 , 400.1 MHz, 25 °C) δ [ppm]: 7.88 (dd, 3 J HH = 8.12 Hz, 4 J HH = 1.08 Hz, 2 H, Naph-4-H), 7.72 (dd, Synthesis of 5,6-(Ph 2 Sb) 2 Acenaph (2). Li 2 Acenaph (120.1 mg, 0.5 mmol) and Ph 2 SbCl (311.42 mg, 1 mmol) were weighed in 25 mL Schlenk tubes and each dissolved in 10 mL of THF.…”

“…While the influence of bulky ligands was largely addressed to their ability to block facile decomposition pathways (kinetic stabilization), recent developments show that the stabilizing effect of such ligands often results from attractive interligand bonding interactions. Attractive dispersion force energies, i. e. London dispersion forces (LDF), [1][2][3] were found to overcompensate repulsive interactions between the ligands resulting from Pauli interaction of the electron clouds, hence significantly contributing to the energetic stabilization and enabling the isolation of a variety of organic [4] and organometallic compounds. [5] The contribution of LDF is not only restricted to attractive interactions between multiple CÀ H moieties of the ligands, [1,6] since attractive metalmetal interactions of easy polarizable metal atoms, [7] in particular of heavy p-block and d-block metals, as well as metal•••ligand interactions [8,9] have been identified as stabilizing effects.…”