Transition metal nitroso complexes

Transition metal nitroso complexes are coordination complexes containing one or more organonitroso ligands (RNO).[1]

## Contents

* 1 Structure and bonding
* 2 Synthesis
* 3 Connection to methemoglobinemia
* 4 References

## Structure and bonding

thumb|right|Structure of the dye Naphthol Green B, which features of nitroso ligand bound to Fe(III).

Organic nitroso compounds bind to metals in several ways, but most commonly as monodentate N-bonded ligands. Also known are O-bonded, η2-N,O-bonded. Dimers of organic nitroso compounds also bind in a κ2\--O,O bidentate manner.

## Synthesis

Organic nitroso complexes can be prepared from preformed organic nitroso precursors. These precursors usually exist as N-N bonded dimers, but the dimer dissociates readily. This direct method is used to give W(CO)5(tert-BuNO) (where tert-Bu is (CH

3C).[2] The Fe-porphyrin complex depicted below is prepared by this route. More complicated but more biorelevant routes involve degradation of precursors such as nitrobenzene and phenylhydroxylamine.[3]

Ni(PEt

4 \+ i–PrNO
2 → Ni(PEt

2(η2−i–PrNO) + PEt
3 \+ OPEt
3 (Et = C2H5, i-Pr = (CH3)2CH)

The coupling of organic ligands and nitric oxide is yet another route.[1]

## Connection to methemoglobinemia

Structure of Fe(octaethylporphyrin)(C6H5NO)(imidazole). This synthetic complex is thought to resemble heme inhibited by nitroso benzene. Color code: red = O, blue = N, Fe, gray = C, white = H.

Methemoglobinemia is a disorder where a large fraction of hemoglobin in one's blood has converted to inactive forms, generically called methemoglobin. Since methemoglobin is not an oxygen-carrier, methemoglobinemia is a serious disorder, sometimes fatal. Exposure to nitrobenzene, aniline, and their derivatives cause this disorder, which is attributed to their conversion to nitrosobenzene (and derivatives), which inactivate hemoglobin by forming a complex with the Fe center, precluding binding of O2.[4]

## References

1. ↑ 1.0 1.1 Lee, Jonghyuk; Chen, Li; West, Ann H.; Richter-Addo, George B. (2002). "Interactions of Organic Nitroso Compounds with Metals". Chemical Reviews 102 (4): 1019–1066. doi:10.1021/cr0000731. PMID 11942786.
2. ↑ Pilato, R. S.; McGettigan, C.; Geoffroy, G. L.; Rheingold, A. L.; Geib, S. J. (1990). "tert-Butylnitroso Complexes. Structural Characterization of W(CO)5(N(O)Bu-tert) and [CpFe(CO)(PPh3)(N(O)Bu-tert)]+". Organometallics 9 (2): 312–17. doi:10.1021/om00116a004.
3. ↑ Berman, R. S.; Kochi, J. K. (1980). "Kinetics and Mechanism of Oxygen Atom Transfer from Nitro Compounds Mediated by Nickel(0) Complexes". Inorganic Chemistry 19: 248–254. doi:10.1021/ic50203a050.
4. ↑ Godbout, Nathalie; Sanders, Lori K.; Salzmann, Renzo; Havlin, Robert H.; Wojdelski, Mark; Oldfield, Eric (1999). "Solid-State NMR, Mössbauer, Crystallographic, and Density Functional Theory Investigation of Fe−O2and Fe−O2Analogue Metalloporphyrins and Metalloproteins". Journal of the American Chemical Society 121 (16): 3829–3844. doi:10.1021/ja9832820.

* v
* t
* e

Coordination complexes

Inorganic ligands

* H2O
* NH3
* N3-
* N2
* O2
* CN−
* CO
* CO2
* F−
* Cl−
* Br−
* I−

Organic ligands
* C5H5
* acac
* CH2＝CH-CH2−
* PR3
* (Me3Si)2N-
* S2C2R22-
* RCN
* =C
* ≡C

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Transition metal nitroso complexes. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Transition_metal_nitroso_complexes&oldid=3331592"
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template