Synthesis and crystal structure of a triple-decker CuII3TlI2 complex: first example of a thallium(I) system in the imino-phenolate Schiff base ligand family

This report deals with the synthesis, characterization, and crystal structure of a heteropentanuclear CuII3TlI2 compound [(CuIIL)3TlI2](NO3)2 (1), where H2L=N,N′-ethylenebis(3-ethoxysalicylaldimine). This compound crystallizes in the monoclinic crystal system within space group C2/c. Each of the two symmetry related thallium(I) centers is located between a terminal and a common, central [CuIIL] by forming bonds with four phenoxo and three ethoxy oxygens. The three [CuIIL] moieties are parallel and hence 1 is a triple-decker system. Neighboring triple-decker moieties are interlinked by π⋯π stacking interaction and weak hydrogen bonds to generate 3-D self-assembly in 1. Salient features in the composition and structure of the title compound are discussed; the title compound is the first example of a thallium(I) system in imino-phenolate Schiff base family.