Ionothermal Synthesis\nof Four New Nickel Thiophosphate Anions: [Ni(P₂S₈)₂]^2–, [Ni(P₃S₉)(P₂S₈)]^3–, [Ni(P₃S₉)₂]^4–, and [(NiP₃S₈)₄(PS₄)]^7–

Abstract

Four new nickel thiophosphate anions have been isolated\nas 1-ethyl-3-methylimidazolium (EMIM) salts: [EMIM]₂[Ni­(P₂S₈)₂] (<b>1</b>), [EMIM]₃[Ni­(P₃S₉)­(P₂S₈)] (<b>2</b>), [EMIM]₄[Ni­(P₃S₉)₂] (<b>3</b>), and [EMIM]₇[(NiP₃S₈)₄(PS₄)] (<b>4</b>). Single\ncrystals of each were prepared by ionothermal reaction of the elements\nin [EMIM]­[BF₄]. <b>1</b> can also be obtained from\n[EMIM]­[CF₃SO₃]. In all four anions, Ni atoms\nare octahedrally coordinated and P atoms are tetrahedrally coordinated.\nIn the anion found in <b>1</b>, two tridentate 1,3-P₂S₈^2– ligands are cis to each other.\nThe anion in <b>2</b> contains two different tridentate thiophosphate\nligands, 1,3-P₂S₈^2– and P₃S₉^3–, whereas the anion in <b>3</b> consists of two P₃S₉^3– ligands coordinated to the central Ni atom. The anion in <b>4</b> is complex, consisting of four NiP₃S₈^– clusters surrounding a central PS₄ tetrahedron;\nwithin the NiP₃S₈^– groups,\none P atom is directly bound to Ni. The discovery of these four new\ncompounds demonstrates the versatility of ionothermal methods for\nthe synthesis of novel thiophosphates.