title: Triamidoamine thorium-arsenic complexes with parent arsenide, arsinidiide and arsenido structural motifs.
abstract: Despite a major expansion of uranium-ligand multiple bond chemistry in recent years, analogous complexes involving other actinides (An) remain scarce. For thorium, under ambient conditions only a few multiple bonds to carbon, nitrogen, phosphorus and chalcogenides are reported, and none to arsenic are known; indeed only two complexes with thorium-arsenic single bonds have been structurally authenticated, reflecting the challenges of stabilizing polar linkages at the large thorium ion. Here, we report thorium parent-arsenide (ThAsH2), -arsinidiides (ThAs(H)K and ThAs(H)Th) and arsenido (ThAsTh) linkages stabilized by a bulky triamidoamine ligand. The ThAs(H)K and ThAsTh linkages exhibit polarized-covalent thorium-arsenic multiple bonding interactions, hitherto restricted to cryogenic matrix isolation experiments, and the AnAs(H)An and AnAsAn linkages reported here have no precedent in f-block chemistry. 7s, 6d and 5f orbital contributions to the Th-As bonds are suggested by quantum chemical calculations, and their compositions unexpectedly appear to be tensioned differently compared to phosphorus congeners.
authors.affiliation: School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Elizabeth P
authors.initials: EP
authors.lastname: Wildman
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, Universitätsstr.31, Regensburg 93053, Germany.
authors.forename: Gábor
authors.initials: G
authors.lastname: Balázs
authors.affiliation: School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Ashley J
authors.initials: AJ
authors.lastname: Wooles
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, Universitätsstr.31, Regensburg 93053, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Scheer
authors.affiliation: School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Liddle