Pseudopolymeric Thallium(I) Di-iso-pentyl Dithiophosphate, [Tl{S2P(O-iso-С5H11)2}]: Synthesis, Structural Organization (Role of Secondary Tl⋅⋅⋅S and Tl⋅⋅⋅O Interactions in Supramolecular Self-Assembly), and Thermal Behavior

Abstract

Crystalline pseudopolymeric thallium(I) di-iso-pentyl dithiophosphate (Dtph), [Tl{S₂P(O-iso-С₅H₁₁)₂}] (I), is synthesized and characterized in detail by single-crystal XRD (CIF file CCDC no. 2296421), simultaneous thermal analysis (STA), multinuclear (¹H, ¹³C, ³¹P) NMR, and IR spectroscopy. Nonequivalent molecules of two types containing Tl(1) and Tl(2) atoms (hereinafter molecules А and В , respectively) are involved (1 : 1) in the formation of the structure of compound I. In both molecules, the S,S  ′-anisobidentate coordination of the Dtph ligands (Tl–S bond lengths 3.006–3.092 Å) results in the formation of small-size four-membered metallocycles [TlS₂P] (a ‘butterfly’ conformation) with significantly averaged P–S bond lengths (1.966–1.985 Å). Molecules A and B are structurally ordered upon the construction of supramolecular chains of two types (⋅⋅⋅A⋅⋅⋅A⋅⋅⋅A⋅⋅⋅)_n and (⋅⋅⋅B⋅⋅⋅B⋅⋅⋅B⋅⋅⋅)_n with oppositely directed structural units combined by paired secondary Tl⋅⋅⋅S and Tl⋅⋅⋅O interactions alternating over the chain length. In turn, paired secondary (but weaker) Tl⋅⋅⋅S interactions occur between molecules A and B belonging to two neighboring pseudopolymeric chains. The multiplicity of these interactions provides the formation of double supramolecular ribbons. The thermal behavior of compound I is studied by the STA technique under an argon atmosphere. Thallium(I) tetrathiophosphate Tl₃PS₄ is identified as the only end product of the thermolysis of compound I. Electron probe microanalysis (EPMA) and scanning electron microscopy (SEM) are used to study the residual substance.