Conformational studies of some potentially bidentate thiosemicarbazones and related complexes of zinc(II)

Abstract

N.m.r. spectra of some potentially bidentate thiosemicarbazones, NR3H*CS*NH.N:CR2R1 (L: R1,R2 = H, Me, Ph, or R1R2 = CI HI 1; R3 = H or Ph), and their complexes [ZnC12L] or [ZnCI,L,] have been measured. The results are compared with semiempirical CN D 0 / 2 total-energy calculations. Only one conformer, containing an intramolecular hydrogen bond, is present in solution. All the zinc(ii) complexes are tetrahedral. The possible formation of complexes in which the ligand is bidentate is discussed. THE synthesis and physicochemical characterisation of EXPERIMENTAL transition-metal complexes with thiosemicarbazone-typeThe starting carbonyl compounds and the thiosemib a n d s is being undertaken in Our laboratory-The carbazidc were Merck reagent-grade products ; 4-phenylinterest in these ligands is connected with their flexithiosernicarbazide was a I< and I< reagent and ZnC1, a n bility which leads to extremely variable behaviour in Erba R P product. Thiosemicarbazones were prepared their reactions with transition and non-transition metals. following tlie procedures of Sah and Daniels.6 TThe crude TABLE 1Analytical data for the thiosemicarbazones Analysis (%I Compound Acetone thiosemicarbazone, (I) C4HgN,S

Synthesis and characterization of organotin(IV) semicarbazones: potential precursors for nanosized tin oxide

“…This could be due to the hindered rotation about the (CO)-NH 2 bond acquiring a partial double-bond character [19][20][21].…”