Thiosemicarbazones as co-ordinating agents. Part 3. Synthesis, spectroscopic characterization, and X-ray structure of methyl pyruvate thiosemicarbazone hemihydrate, chloro(ethyl pyruvate thiosemicarbazonato)copper(II)(green form), and chloro(pyruvic acid thiosemicarbazonato)copper(II) dihydrate (blue form)

Abstract

Three new compounds, methyl pyruvate thiosemicarbazone hemihydrate Hmpt·0.5H2O (1), chloro(ethyl pyruvate thiosemicarbazonato)copper(II), [{CuII(ept)Cl2}](2), and chloro(pyruvic acid thiosemicarbazonato)copper(II) dihydrate, {[CuII(Hpt)Cl]·2H2O}n(3), have been synthesized and characterized using single-crystal X-ray diffraction methods. The following results were obtained: (1); space group C2/c, a= 12.406(1), b= 10.838(1), c= 12.845(1)Å, β= 97.79(1)°, Z= 8, R0.040, R′ 0.048. (2), P21/n, a= 11.785(1), b= 8.202(1), c= 11.057(1)Å, β= 95.70(1)°, Z= 4, R0.042, R′ 0.045. (3); P21/c, a= 8.496(1), b= 18.046(2), c= 7.184(1)Å, β= 109.90(1)°, Z= 4, R0.031, R′ 0.033. In (1) the compound is in the fully extended conformation showing an E configuration about both the C(2)–N(3) and C(1)–N(2) bonds, but a Z configuration about C(2)–C(3)[with respect to donating centres S, N(3), and O(1)]. In (2) the organic molecule is hydrolyzed and transesterificated to form chloro(ethyl pyruvate thiosemicarbazonato)copper(II)(green form)(dimeric), while in (3) it is hydrolyzed only to form chloro(pyruvic acid thiosemicarbazonato)-copper (II) dihydrate (blue form)(polymeric). The main vibrational bands are also reported and discussed.