Copper complexes electronic structure

A series of copper(II) complexes with ring-substituted phen-ligands have been synthesized and their molecular structural and electronic structural properties have been investigated.246 Each structure ((280) r = 0.72, (281) r = 0.81, (282) r = 0.88, (283) r = 0.83, and (284) r = 0.68) is characterized by a distorted trigonal-bipyramidal arrangement of ligands around copper. 

A number of heteroaromatic monothiocarboxylic acids are formed by Pseudomonas sp. From P. putida, there was isolated pyridine-2,6-di-(mon-othiocarboxylic acid) 46 (Scheme 16). Of interest is the fact that in P. stutzeri KC, a copper complex of 46 is the active agent for a one electron transfer in the bacterial biodegradation of CCI4. Methylation of P. putida extracts provides a number of related structures such as 47. In addition, a P. fluorescens sp. contains 8-hydroxy-4-methoxy-quinoline-2-monothiocarboxylic acid 48.98... 

The structures of metal-complex dyes, which must exhibit a high degree of stability during synthesis and application, is limited to certain elements in the first transition series, notably copper, chromium, iron, cobalt and nickel. The remaining members of the transition series form relatively unstable chelated complexes. The following description of the influence of electronic structure, however, is applicable to all members of the series. 

An EPR and ENDOR investigation of the planar copper complex 63Cu(sal)2 (Fig. 30) substituted into a single crystal of Ni(sal)2 has been reported by Schweiger et al.62,65). The aim of this work was to determine the structure of the internal H-bond occuring in Cu(sal)2, and to draw a detailed picture of the unpaired electron distribution on the... 

It is well known that crystal and electronic structures are interdependent and define the reactivity of chemical substances. In Section 1.4.2, it was noted that copper-porphyrin complex gives cation-radicals with significant reactivity at the molecular periphery. This reactivity appears to be that of nucleophilic attack on this cation-radical, which belongs to n-type. The literature sources note, however, some differences in the reactivity of individual positions. A frequently observed feature in these n-cation derivatives is the appearance of an alternating bond distance pattern in the inner ring of porphyrin consistent with a localized structure rather than the delocalized structure usually ascribed to cation-radical. A pseudo Jahn-Teller distortion has been named as a possible cause of this alternation, and it was revealed by X-ray diffraction method (Scheidt 2001). 

Physical Measurements on Copper Complexes.—Detailed discussion of papers concerned purely with spectroscopic and magnetic data obtained for copper complexes is now covered by the Chemical Society Specialist Periodical Report Electronic Structure and Magnetism of Inorganic Compounds (ed. P. Day), Volumes 1 and 2, and will not be included here. However, three papers of some significance are cited below and other papers on this subject listed in Table 5. 

Hathaway has attempted to assess the value of the electronic properties of polycrystalline mononuclear copper complexes with the [CUN4], [CuNj], and [CuN ] chromophores of unknown crystal structure, in predicting the stereochemical environment of the copper(ii) atom. The value of having B. J. Hathaway, J.C.5. Dalton, 1972, 1196. 

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