Bonding and Phosphorescence Trends in 1-D, 2-D, and 3-D Oligomers and Extended Excimers of Group 12 Metals: Validation of Cooperativity in Both Metallophilic and Excimeric Bonding

Abstract

Spectroscopic and bonding trends of group 12 clusters of various size (M2–8) have been studied to assess proper models for solid-state materials that exhibit ground-state metallophilic bonding and excited-state excimeric bonding. Both of these bonding types are found to exhibit increased bond strength as the cluster size increases, hence modulating the bond distance and spectroscopic constants and manifesting cooperativity in the 1Σ ground state and lowest-lying 3Σ and 3Π open-shell excited states. The cooperative bonding effects are shown to be caused by delocalization of the electron density as the size of the clusters increases. Spin-forbidden excitation and emission energies correspond to electron delocalization of the clusters, hence exhibiting red shifts with cluster size increase. The electron delocalization and, consequently, the bonding and photophysical parameters are studied as a function of cluster size and shape upon 1-D, 2-D, or 3-D growth of the cluster atoms. Near convergence in the cooper...