Solution and solid-state structural study of the copper(II) complex of diazepam

Article abstract of DOI:10.1021/ic50204a003

The complex Cu(L)₂Cl₂ (L = 7-chloro-1,3-dihydro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one, also known as diazepam) has been prepared and studied in solution and solid states. The complex crystallizes in the trigonal system (space group R3) with a = 18.645 (2) ? and α = 117.52 (1)°. The structure was resolved by using 2594 reflections, by difference Fourier techniques, to a final R of 0.045, by least-squares refinement using anisotropic thermal parameters. The formula unit is Cu(L)₂Cl₂(H₂O)₂·0.33CHCl ₃. The metal atom is in a square-planar environment, coordinated to two nitrogens from the ligands (Cu-N = 1.990 (8) ?) and two chlorine atoms in a trans geometry (Cu-Cl = 2.27 (20) ?). The boat conformation of the seven-membered ring is maintained in the complex. The EPR and ¹³C NMR results support a similar coordination of the Cu²⁺ ion in solution as that found in the solid state. The relation between the solid-state features and the solution properties is discussed.