Structural characterization of rare intramolecularly (1,4-Te· · ·N) bonded diorganotellurides and their monomeric complexes with mercury(II) halides: metal assisted C-H· · ·X (Hg) interactions leading to supramolecular architecture

Monomeric tellurides 4-RC₆H₄(SB)Te [SB = 2-(4,4'-N0₂C₆H₄CH=NC₆H₃-Me); R = H, <span style="font-weight: bold;">1</span><b>a</b>; Me,<span style="font-weight: bold;">1</span><b>b</b>; OMe, <span style="font-weight: bold;">1</span><b>c</b>], which incidentally represent the first example of a telluride with 1,4-Te···N intramolecular interaction, have been prepared and characterized by solution and solid-state ¹²⁵Te NMR, ¹³C NMR and X-ray crystallography. Interplay of weak C-H···O and C-H-··π{ interactions in the crystal lattice of <span style="font-weight: bold;">1</span><b>b</b> and<span style="font-weight: bold;">1</span><b>c</b> are responsible for the formation of supramolecular motifs. These tellurides undergo expected oxidative addition reactions with halogens and interhalogens and also interact coordinatively with mercury(II) halides to give 1:2 complexes, HgX₂[4-RC₆H₄(SB)Te]₂ (X = CI, R = H, <b>2a</b>; Me, <b>2b</b>; OMe, <b>2c</b> and X = Br, R = H, <b>3a</b>; Me, <b>3b</b>; and OMe, <b>3c</b>) with no sign of Te-C bond cleavage, as has been reported for some 1,5-Te·· ·N(O) intramolecularly bonded tellurides. The complexes <b>2a</b> and <b>3c</b> are the first structurally characterized monomeric 1:2 adducts of mercury(II) halides with Te ligands. The 1,4-Te···N intramolecular interactions in the solid-state are retained in the complexes highlighting simultaneously the Lewis acid and base character of the Te(lI) atom. Packing of molecules in the crystal lattice of <b>2a</b><br />and <b>3c </b>reveals that non-covalent C-H· . ·Cl/Br interactions involving metal-bound halogen atoms possess significant directionality and in<br />combination with coordinative covalent interactions may be of potential use in creating inorganic supramolecular synthons.<br />