The Structural Aspects of Mutually Trans-X-Cu(I)-X (X = OL, NL, CL, PL, SL, SeL, Cl or Br) Complexes

The structural parameters for sixty mutually trans-(X-Cu(I)-X) (X = OL, NL, CL, PL, SL, SeL, Cl or Br, where OL, NL, CL, PL, SL, and SeL are ligands L with respective donor atoms O, N, C, P, S and Se) complexes were analyzed and classified. Within the studied group, there are two types of complexes; the by far most common one is based on coordination, and another one is organometalics based on only C-donor atoms. Linear and bent geometric possibilities exist for coordination number two. The former is dominant in the structures of mutually trans -X–Cu(I)-X. In general, there are three preparative procedures; the most common is the direct reaction of a copper(I) salt with the ligands in a non-aqueous solution (mostly acetonitrile). Copper(I) complex cations can be isolated from salts with larger anions. Unidentate ligands occupy two coordination sites, which results in the linear arrangement. The X–Cu(I)–X angles are between 172.3° and 180°. Overall, it is observed that the mean Cu–X distance increases the covalent radius of the ligating atom in the sequence 1.849 Å (O, 0.73 Å) < 1.886 Å (N, 0.75 Å) < 1.900 Å (C, 0.77 Å) < 2.104 Å (Cl, 0.99 Å) < 2.137 Å (S, 1.02 Å) < 2.236 Å (P, 1.06 Å) < 2.244 Å (Br, 1.14 Å) < 2.260 Å (Se, 1.17 Å).