Prof. Nik Kaltsoyannis PCCP paper predicts the shortest Th–Th distance from a new type of quadruple bond

Work by Dr Han-Shi Hu and Prof. Nik Kaltsoyannis has discovered a new type of Th–Th quadruple bond with the shortest Th–Th distance yet reported

This is achieved by coordinating neutral donor ligands such as PH3 and AsH3 in an end-on fashion to the Th2 dimer. Density functional theory and ab initio methods, at both the scalar and spin‑orbit levels, are used to probe the Th–Th bonding in a range of zero valent systems of general formula LThThL. Several of these compounds have very short Th–Th bonds arising from a new type of Th–Th quadruple bond with a previously unreported electronic configuration featuring two unpaired electrons in 6d based d bonding orbitals. H3AsThThAsH3 is found to have the shortest Th–Th bond yet reported (2.590 Å). The Th2 unit is a highly sensitive probe of ligand electron donor/acceptor ability; we can tune the Th–Th bond from quadruple to triple, double and single by judicious choice of the L group, up to 2.888 Å for singly bonded ONThThNO.

Han-Shi and Nikolas Kaltsoyannis, Physical Chemistry Chemical Physics (2017) DOI: 10.1039/c7cp00113d


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