The polarised single-crystal electronic and 8.s.r. spectra of K3Cu(N02), have been determined and are shown to be consistent with the stereochemistry of the two non-equivalent copper( II) environments present namely, a sevenco-ordinate [CU(NO~)~(ONO),]~-and a cis-distorted six-co-ordinate [Cu(NOz)2(ONO)z(ONO)]3-species. The i.r. spectrum is shown to be compatable with the presence of nitro-and unidentate and bidentate nitritoligands, but cannot distinguish the two types of nitrito-co-ordination. A structural pathway is suggested between the seven-co-ordinate and cis-distorted species.THE complex K3Cu(N0,), (1) has been known for a considerable time l 3 and has aroused much interest 4p5 as a possible five-co-ordinate copper( 11) complex involving five potentially equivalent nitro-ligands. The recent X-ray crystal-structure determination of (1) has established that there are two types of non-equivalent copper(@ ion environments, neither of which is five-coordinate : one involves a seven-co-ordinate pentagonalbipyramidal [CU(NO,),(ONO),]~-anion, and the other a cis-distorted [Cu(NO,),(ONO),(ONO)] 3-anion, Figure l(a) and (b), respectively. The nitrite ligands involve three distinct types of co-ordination,' namely nitro, unidentate nitrito, and bidentate nitrito. As the original e.s.r. spectrum6 of (1) was reported as axial, consistent with an elongated tetragonal-octahedra1 stereochemistry, and as the original electronic spectrum was reported as a single peak at 14 710 cm-l in contrast to the twin peaks predicted for a cis-distorted octahedral structure,8 the electronic properties have been redetermined and are now reported in the light of the known crystal structure of (1).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.