Crystal and molecular structure of dimethyl 4-phenyl-S-methylisothiosemicarbazide diacetate and its complex with copper(II) bromide

The structure of dimethyl 4-phenyl-S-methylisothiosemicarbazide diacetate NH(C₆H₅)C(SCH₃)NN × (CH₂COOCH₃)₂ (Z) hydroiodide (I) (crystals I are triclinic, space group $Pbar 1$ , a=11.671(3), b=10.889(2), c=8.237(2) Å,α=78.59(2),β=77.63(2),γ=106.47(2)°, Z=2, final R=0.088) and a complex of Z with copper(II) bromide, CuBr₂Z (II) (crystals II are orthorhombic, space group Pbca, a=14.487(4), b=18.827(8), c=14.565(5) Å, Z=8, R=0.062) was determined by X-ray diffraction analysis. It is established that methylation of the sulfur atom changes the type of ligand attachment to the metal, namely, the ligand is transformed from the tripod S,N,O,O, into the N,N,O,O type (the sulfur atom is not involved in coordination). When coordinated, the ligand does not change conformation, and the thiosemicarbazide fragment retains the E-configuration. During complexation, Z topologically behaves as a classical complexon of the monoamine series.