Copper(II) complexes of 6-methyl-2-formylpyridine 4N-substituted thiosemicarbazones

Abstract

Copper(ll) complexes of 6-methyl-2-formylpyridine thiosemicarbazone, and its *N-methyl-, *N-ethyl-, 4N-phenyl-, 4N-dimethyl-, 4N-diethyl-, 4N-dipropyl-, 3-pyrrolidinyl, 3-piperidinyl-and 3-hexamethyleneiminylthiosemicarbazone derivatives were prepared and characterized. I.r., electronic and e.s.r, spectra of the complexes, as well as ~H and ~ 3C n.m.r, spectra of the thiosemiearbazones, were obtained. The thiosemicarbazones and their eopper(II) complexes show either modest or no growth inhibitory activity against Aspergillus niger, but the *N-dialkyl-and 3-azaeyclo-derivatives exhibit considerable activity against Paecilomyces variotii.

Copper(II) and nickel(II) complexes of 2-formylpyridine 3-piperidinyl-, 3-hexamethyleneiminyl- and 3-azabicyclo[3.2.2]nonylthiosemicarbazones

“…In DMF the axial position is either occupied by a solvent molecule or vacant so that there is less effect on replacement of the weaker bonding bromo axial ligand compared to a chloro ligand. Solid complexes of the more sterically hindered thiosemicarbazones derived from 6-methyl-2-formylpyridine, [Cu(6Mpip)Cl2] and Cu(6Mhexim)C12], have room temperature gll values of 2.214 and 2.207, respectively (25). The much higher values for these latter complexes compared to the present complexes shows the sensitivity of gfl to the ligand field.…”

Spectral, magnetic, thermal and electrochemical studies on phthaloyl bis(thiosemicarbazide) complexes

“…Phthaloyl bis(thiosemicarbazide) 1739 of (N 2 H); (ii) the negative shift (10-65 cm À1 ) of (C¼N) [11]; (iii) the positive shift of (N-N); (iv) coordination of the azomethine nitrogen is also consistent with the presence of a new band at 410-445 cm À1 assignable to the (M-N) vibration [12]; and finally (v) coordination via thiolate sulfur is indicated by the absence of (C¼S) vibration with the simultaneous appearance of new bands in the 610-690 and 325-370 cm À1 regions due to the (C-S) and (M-S) vibrations [13,14], respectively. The existence of stretching and bending OH bands, which are more or less invariant, indicates that this group is not taking part in coordination.…”

Copper(II) complexes of 6-methyl-2-acetylpyridine N(4)-substituted thiosemicarbazones

“…Each thiosemicarbazone exhibits a peak at ca 30000cm-1 in its solid state spectrum (Table 4). Generally, this band is at somewhat higher energy in the solution (DMSO) spectra, as was found for the analogous 6-methyl-2-forrrkylpyridine thiosemicarbazones (6). It has a molar absorptivity in the 1.2 x 103 2.5 x 104(loge 3.09-4.30) range, and is assignable to the n-~* transition of the pyridine ring (13).…”

“…This increase in d d band energy with increased Table 5. Solid state e.s.r, spectral parameters of the copper(II) complexes of H6ML4M, H6ML4E, H6ML4DM, H6ML4DE, H6ML4DP, H6MLpip and H6MLhexim bulkiness of the N(4)-substituent is opposite to the trend observed for the 6-methyl-2-formylpyridine thiosemicarbazone complexes (6). For the five-coordinate complexes, the e.p.r, parameters (Table5) are consistent with non-planar copper(II) centres and correlate well with distorted square pyramidal Cu(HNNS)C12 stoichiometry.…”