A Brief Account on Copper Nitrosyl Complexes

Because of the amazing flexibility of nitric oxide (NO) as a net electron giver or acceptor in metal-NO binding interactions, chemists have long been interested in such interactions. Later it has been found that NO has a diverse role in biology and most of its activities are linked to formation of nitrosyl complexes with various metalloproteins. Copper has a very significant role in mammalian biochemistry as a part of a number of metalloenzymes, viz. cytochrome oxidase, lacase, nitrous-oxide reductase, nitrite reductase, catechol oxidase etc. It has been observed that many of these enzymes in their oxidized or reduced state react with NO leading to various reactions. In most of these, involvement of a copper nitrosyl intermediate has been implicated. The electronic structure and NO binding modes of such intermediate is of immense importance to understand the mechanism of such interactions. However, thermal instability of copper nitrosyls precludes the possibility of attaining much insights in this regard. Functional small molecule model complexes could be useful in these kinds of circumstances. This prompted researchers worldwide to try synthesizing copper nitrosyl complexes. This article is an attempt to summarize the significance advancement in this regard. In this article, an attempt has been made to highlight the noteworthy progress made in this area.