Cobalt(III) and Chromium(III) Complexes with Ethylenediaminemonoacetic Acid

Abstract

Cobalt(III) and chromium(III) complexes with ethylenediaminemonoacetic acid (EDMA), [Co(edma)2]Cl·2H2O and [Cr(edma)2Cl·3H2]O, (edma: H2NCH2CH2NHCH2COO−), were prepared. The former complex was isolated as two geometrical isomers. From the electronic absorption spectra, the two isomers were assigned to trans and cis forms with respect to the carboxylate oxygen atoms coordinated. Chromium(III) complex was concluded to have the trans form by comparing the IR spectrum with those of the above two isomers of cobalt (III) complexes.

Ethylenediammonium bis{bis[N-(2-aminoethyl)glycinato-κ3N,N′,O]chromium(III)} tetrachloride dihydrate at 293 and 100 K

“…The chemical formula is different from that previously suggested by Fujii et al (1970). This is in agreement with the elemental analysis.…”

“…The ligand HedmaÁ2HClÁH 2 O and the title complex were prepared according to the literature method of Fujii et al (1970). Recrystallization of the complex from 10% ethanol solution gave bright-red crystals of (I) suitable for crystallographic analysis.…”

“…N-(2-Aminoethyl)glycinate [ethylenediaminemonoacetate or 4-amino-2-azabutanecarboxylate (edma)] has one acetate group and two amino groups, and can act as a tridentate ligand in complexation with cobalt(III) or chromium(III) ions (Fujii et al, 1970;Battaglia et al, 1974;Ama et al, 1985;Okamoto et al, 1991;Yasui et al, 1994). On the basis of elemental analysis and visible absorption, 13 C NMR and circular dichroism spectra, the molecular structure of the cobalt(III) complex with the edma ligand has been determined (Igi & Douglas, 1974;Yasui et al, 1983).…”

“…Of these, only a trans form with respect to the coordinated carboxylate O atoms has been isolated and its spectroscopic properties reported (Fujii et al, 1970;Yuen, 1981). There are six possible geometric diastereomers of the bis[N-(2-aminoethyl)glycinato]chromium(III) moiety, as shown in the Scheme below.…”

Organotemplate-Free Hydrothermal Synthesis of Isomorphously Co-Substituted Mordenite Molecular Sieve

“…All the Co-mordenites presented well-resolved triplet bands in the wavelength range of 500-650 nm, attributable to 4 A2→ 4 T1 ( 4 P), 4 A2→ 4 T1 ( 4 F), and 4 A2→ 4 T2 transitions of high-spin Co 2 + in tetrahedral coordination sites. 17,[35][36][37][38][39][40][41] In contrast, the triplet band could not be found for the pure mordenite. Furthermore, except for the sample with a very high n(Co)/n(SiO2) ratio of 0.05, the relative intensities of the triplet bands increased with Co contents in initial gels, which again suggests that the more Co 2+ introduced into initial gels, the more Co 2+ incorporated in MOR frameworks.…”