Discrete molecular and extended polymeric copper(I) halide complexes of tetradentate thioether macrocycles

Abstract

A series of complexes of copper(I) halides with either [12]aneS4 (1,4,7,10-tetrathiacyclododecane) or [16]aneS4 (1,5,9,13-tetrathiacyclohexadecane) have been synthesized, characterised and their crystal structures determined. Discrete molecular entities of formula [CuX([12]aneS4)] (X = Cl, Br or I) were isolated from solutions containing a 1∶1 metal∶ligand stoichiometry. In [CuX([12]aneS4)] (X = Br or I) the copper(I) centres adopt a rare square pyramidal geometry. Located on fourfold axes of symmetry, the copper(I) centres are co-ordinated by one halide ion [Cu–Br 2.4209(11) or Cu–I 2.573(5) A] and four sulfur atoms [2.5386(12) (X = Br) and 2.521(5) A (X = I)]. In contrast, the copper(I) centres in [CuCl([12]aneS4)] adopt the more common tetrahedral co-ordination geometry, which is provided by one chloride ion [Cu–Cl 2.2666(13) A] and three sulfur donors [Cu–S 2.3331(13), 2.3326(13), 2.4720(11) A]. Polymeric materials, [Cu4Br4([12]aneS4)2]∞, [Cu4I4([12]aneS4)]∞ and [Cu2I2([16]aneS4)]∞, were obtained from reactions in which metal∶ ligand stoichiometries of 2∶1 and 4∶1 were used. [Cu4Br4([12]aneS4)2]∞ contains a previously uncharacterised copper(I) halide motif of formula Cu4X4 which is derived from the common Cu4X4 cubane tetramer and the Cu4X4 step-cubane tetramer. These Cu4X4 clusters are linked by [12]aneS4 molecules to generate a two-dimensional framework [Cu–Br 2.410(2)–2.539(2); Cu–S 2.318(3)–2.385(3) A]. In [Cu4I4([12]aneS4)]∞, Cu4I4 cubane tetramers are linked by tetradentate [12]aneS4 molecules to give a two-dimensional sheet structure [Cu–I 2.602(1)–3.021(1); Cu–S 2.285(1)]. In [Cu2I2([16]aneS4)]∞ an infinite three-dimensional co-ordination polymer comprising Cu2I2 rhomboid dimers linked by tetradentate [16]aneS4 molecules is formed [Cu–I 2.5972(9)–2.6702(9); Cu–S 2.292(2)–2.357(2) A]. The Cu2I2 moiety acts as a pseudo-square planar linker while the bridging [16]aneS4 units afford tetrahedral building blocks to give overall a PtS type structure for the polymer.