Aminotroponiminato(chloro)germylene stabilized copper(I) iodide complexes: synthesis and structure.

Reaction of an aminotroponiminato(chloro)germylene [(i-Bu)2ATIGeCl] (1) (ATI = aminotroponiminate) with CuI in acetonitrile afforded an aminotroponiminato(chloro)germylene stabilized copper(I) iodide complex [{(i-Bu)2ATIGeCl}2(Cu4I4)(CH3CN)2] (2) with a tetrameric distorted cubane type Cu4I4 core. The reaction of compound 1 in dichloromethane with CuI in the presence of 2 equiv of pyridine resulted in the first germylene stabilized copper(I) iodide complex [{(i-Bu)2ATIGeCl}(CuI)(C5H5N)2] (3) with a monomeric CuI core. A reaction of compound 1 with equimolar amounts of CuI and pyridine in dichloromethane resulted in a copper(I) iodide complex [{(i-Bu)2ATIGeCl}2(Cu2I2)(C5H5N)2] (4) with a dimeric Cu2I2 core. Interestingly, an interconversion between compounds 3 and 4 and conversion of compound 2 to compounds 3 and 4 under suitable conditions are also reported. The compounds 2-4 have been characterized by multinuclear NMR spectroscopy and single-crystal X-ray diffraction studies. The copper atoms in all these complexes are tetracoordinate, and the Ge(II)-Cu(I) bond lengths in complexes 2, 3, and 4 are 2.341(1), 2.308(1), and 2.345(1) Å, respectively.