The electronic spectra of nickel(II) bis(dithiocarbamate) chelates

Abstract

The synthesis and electronic spectra of the chelates of nickel(II) dithiocarbamates with ligands derived from dimethyl-, diethyl-, dipropyl-, dibutyl-, dipentyl-, dihexyl-, diheptyl-, dioctyl-, diisopropyl-, methylisopropylamine, piperidine, morpholine and piperazine are discussed. The absorption bands in the chelate spectra around 220 and 245 nm are assigned to absorption localized primarily in the S-C=S and N-C=S ligand groups. The analytically most important band with λmax around 330 nm assigned to M-L charge transfer is affected by alkyl substituents on the nitrogen atom and by the solvent polarity. The lengthening of the alkyl chain causes the increase in the intensity of the band and red-shift of its λmax; the increase of the polarity of the solvent leads to an increase in the band intensity and a blue shift.

Pyrrole-based metallo-macrocycles and cryptands

“…The electronic absorption transition bands were assigned by reference to the literature. 35,36 Excellent agreement between experiment and binding curves derived theoretically by Specfit 34 for 1 : 1 complexation was observed for (7-Ni) and Ni-(dedtc) 2 , allowing the calculation of the corresponding stability constants; the 1 : 1 stoichiometry was confirmed by Job's method. 37 Specfit could not fit the data for (2-Ni), probably due to 2 : 1 acetate: (10-Ni) binding becoming significant at higher acetate concentrations.…”

Ultraviolet and light absorption spectrometry

“…The absorbance of the cupric thiocyanate complex in acidic solution was shown to vary markedly with the nature and concentration of acid used (211). The effect of hydrocarbon chain length on the nitrogen substituent and of solvent polarity on the position of the analytically important ultraviolet absorption bands of nickel bis(dithiocarbamate) chelates has been determined (384).…”