Nitrosyl cation nitrosonium

Nitrosyl cation is also called nitrosonium ion It can be represented by the two reso nance structures... 

Thus, unlike NO, HNO (not N—OH) can target cardiac sarcoplasmic ryanodine receptors to increase myocardial contractility, can interact directly with thiols and is resistant to both scavenging by superoxide (OJ) and tolerance development (Irvine et al. 2008). Nitrosonium (sometimes also termed nitrosyl cation) is very short lived in aqueous solution. Nitrosonium ions react with secondary amine to generate nitrosamines, many of which are eancer-inducing agents at very low doses (5.219). NO"" is formed in very small concentrations from nitrous acid in strong acid solution, when HNO2 reacts as a base ... 

A majority of the nitrosyl complexes contain NO (nitrosyl or nitrosonium ion) as the hgand. The nitrosyl cation is isoelectronic with carbon monoxide. Hence, the bonding between nitrogen and metal in nitrosyls is analogous to that of carbon and metal in carbonyls. However, the hgand nitrosyl (NO ) is a three-electron donor, as it donates one electron to the metal ion prior to the donation of an electron pair for the formation of a coordinate covalent bond. 

Nitrosonium ion was found to promote iodination of cyclohexene when AcOH was used as solvent, the trans-iodo acetoxy derivative was formed in a good yield. Solvolysis of the latter, followed by saponification, led to a cA-diol so that this method can serve as an alternative to the wet-Prdvost reaction. The NO+ cation is believed to promote the formation of some positive iodine species (equation 1). Oxidation by oxygen leads to the regeneration of iodine and NO+ from nitrosyl chloride189. 

The nitrosonium cation [NO]+ is isoelectronic with CO and accordingly many mixed nitrosyl-carbonyl complexes are known. For electron counting purposes, the neutral molecule is considered to act as a 3 (or occasionally 1) VE donor. Thus various series of isoelectronic complexes can be envisaged (Table 3.5). The majority of synthetic routes to nitrosyl-carbonyl complexes involve (i) photochemical CO substitution or metal-metal bond cleavage by NO (ii) electrophilic attack by nitrosonium salts, e.g. [NO]BF4 or nitrosyl halides (e.g. C1NO) upon electron-... 

Neutral (cyclobutadiene)iron complexes undergo thermal and photochemical ligand substitution with phosphines, with alkenes such as dimethyl fumarate and dimethyl maleate, and with the nitrosonium cation. Cationic nitrosyl complexes (e.g. 210) undergo ligand substitution by treatment with phosphines. Photolysis of (tetraphenylcyclobutadiene)Fe(CO)3 in THF at -40 °C is reported to give the novel bimetallic complex (214), which reacts with carbon monoxide (140 atm, 80 °C) to regenerate the starting material.An X-ray diffraction analysis of (214 R = Ph, R = t-Bu) reveals a very short Fe-Fe distance of 2.117 A. 

One electron oxidation of NO generates the nitrosonium cation (N0+). In this reaction, the iron atom of Fe(III)-containing metalloenzymes acts as the electron acceptor. The metal-nitrosyl complex formed (Fe(II)-NO+)... 

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