Synthesis, structure, spectroscopic and magnetic properties of two copper(II) dimers containing pyridine-2-carbaldehyde thiosemicarbazonate (L), [{CuL(X)}₂](X = Cl or Br)

Coordination Modes in a Tridentate NNS (Thiosemicarbazonato)copper(II) System Containing Oxygen‐Donor Coligands − Structures of [{Cu(L)(X)}2] (X = Formato, Propionato, Nitrito)

“…These values are similar to those observed for other pyridine-2-carbaldehyde thiosemicarbazone derivatives containing copper() ions in distorted square-pyramidal topologies, with a d x 2 Ϫy 2 ground state. [2,3,5,6] The O-bridged dimer is the most rhombic and has the largest value for g 1 , which is in good accordance with the differences in the crystal structure.…”

“…[6] Several structural differences between dinuclear S-and X-bridged complexes have been found. The presence of S-bridges is due to p ϩ sp 2 hybridising of the thiolato sulfur atom. The results suggest that the electron density of the S p z orbital in the S-bridged systems is less delocalised towards the thiosemicarbazone chain than that of the X-bridged complexes.…”

“…The anionic L Ϫ form is usually present in [{Cu(L)X} 2 ] dimers. In these dinuclear compounds, the metal centres can either be bridged through the sulfur enethiolato atom (X ϭ Cl, Br, NCS) [2,3] or the non-thiosemicarbazone coligands [4,5] (X ϭ CH 3 CH 2 COO Ϫ , Scheme 2). In recent work, we have tried to rationalise the structural, spectroscopic and magnetic aspects of this system by means of comparative structural studies and approximate molecular orbital calculations.…”

“…[2,3] One of the factors to be considered is the nature of the terminal coligands placed in the basal plane. In our case, O-donor coligands show the smallest J values.…”

New 1,3,4‐Oxadiazolecopper(II) Derivatives Obtained from Thiosemicarbazone Complexes

“…The product was identified as the [{Cu(L I )(Br)} 2 ] complex. [34] Bright green crystals of 5 were then obtained from the mother liquor after one week at room temperature (0.22 g, 58% yield). C 24 Ligand 7 can also be prepared by oxidative cyclization of HL I in the absence of copper() as follows: solid potassium bromate (0.5 g, 3 mmol) was added to a suspension of the thiosemicarbazone in water (0.54 g, 3 mmol) acidified with H 2 SO 4 to pH ϭ 0Ϫ1.…”