Premium
Metal‐Catalysed Oxidation Processes in Thiosemicarbazones: New Complexes with the Ligand N ‐{2‐([4‐ N ‐Ethylthiosemicarbazone]methyl)phenyl}‐ p ‐toluenesulfonamide
Author(s) -
Pedrido Rosa,
Romero María J.,
Bermejo Manuel R.,
GonzálezNoya Ana M.,
GarcíaLema Iria,
Zaragoza Guillermo
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200700867
Subject(s) - ligand (biochemistry) , chemistry , semicarbazone , manganese , metal , copper , stoichiometry , schiff base , inorganic chemistry , electrochemistry , crystallography , medicinal chemistry , organic chemistry , biochemistry , receptor , electrode
The coordination behaviour of a new thiosemicarbazone Schiff‐base building block, N ‐{2‐([4‐ N ‐ethylthiosemicarbazone]methyl)phenyl}‐ p ‐toluenesulfonamide, H 2 L 1 ( 1 ), incorporating a bulky tosyl group, towards Mn II , Fe II , Co II , Ni II , Cu II , Zn II , Cd II , Ag I , Sn II , and Pb II has been investigated by means of an electrochemical preparative procedure. Most metal complexes of L 1 have the general formula [M(L 1 )] 2 ⋅ n X (M=Mn, Fe, Co, Ni, Cu, Cd, Pb; n =0–4, X=H 2 O or CH 3 CN), as confirmed by the structure of [Pb(L 1 )] 2 ( 15 ), in which the lone pair on lead is stereochemically active. This lead(II) complex shows an intense fluorescence emission with a quantum yield of 0.13. In the case of silver, the complex formed was found to possess a stoichiometry of [Ag 2 (L 1 )] 2 ⋅3 H 2 O. During reactions with manganese and copper metals, interesting catalysed processes have been found to take place, with remarkable consequences regarding the ligand skeleton structure. In synthesising the manganese complex, we obtained an unexpected dithiolate thiosemicarbazone tosyl ligand, H 2 L 2 , as a side‐product, which has been fully characterised, including by X‐ray diffraction analysis. In the case of copper, the solid complex has the formula [CuL 1 ] 2 , but the crystallised product shows the copper atoms coordinated to a new cyclised thiosemicarbazone ligand, H 2 L 3 , as in the structures of the complexes [Cu(L 3 )] 2 ⋅CH 3 CN ( 8 ) and [Cu(L 3 )(H 2 O)] 2 ⋅CH 3 CN⋅H 2 O ( 9 ). The zinc complex [Zn(L 1 )] 4 ( 12 ) displays a particular tetranuclear zeolite‐type structure capable of hosting small molecules or ions, presumably through hydrogen bonding.