Copper(I) diselenocarbamate clusters: synthesis, structures and single-source precursors for Cu and Se composite...

Neutral tetrahedral [Cu4(Se2CNnPr2)4] (1), monocationic hydride-centered tetracapped tetrahedral [Cu8(H){Se2CNR2}6]+ (R = nPr, 2H; Et, 3H) and neutral hydride-centered tricapped tetrahedral [Cu7(H){Se2CNR2}6] (R = nPr, 4H; Et, 5H) clusters were formed. They are the first Cu(I) complexes supported by dialkyl diselenocarbamates. The as-synthesized complexes 2H and 3H, formed from a reaction mixture of Cu(I) salts, diselenocarbamates, and [BH4]− in an 8:6:1 ratio, can be further reduced to 4H and 5H, respectively, in the presence of one equiv. of [BH4]−. Replacement of [BH4]− with [BD4]− afforded the deuteride analogues [Cu8(D){Se2CNR2}6]+ (R = nPr, 2D; Et, 3D) and [Cu7(D){Se2CNR2}6] (R = nPr, 4D; Et, 5D), which confirm the presence of hydride in the corresponding (2H, 3H, 4H and 5H) compounds. These complexes were fully characterized by elemental analysis, ESI-MS, and 1H, 2H and 77Se NMR spectroscopy, and their molecular structures were unequivocally established by single crystal X-ray crystallographic analyses (1, 2H–5H). The hydride-encapsulated copper frameworks of (2H, 3H) and (4H, 5H) reveal a tetracapped tetrahedral cage of Cu8 and a tricapped tetrahedral cage of Cu7, respectively, which are enclosed within a Se12 icosahedron constituted by six dialkyl diselenocarbamate ligands. Compounds 2H and 3H display orange emission in both the solid and solution state under UV irradiation at 77 K. In addition, the thermolysis behaviors of 2H were studied to demonstrate the potential of these compounds as single-source precursors for copper selenide nanocomposites, which were analyzed by XRD, EDX, and SEM techniques.