Electrophilic substitution reactions in heterocycles complexed to exchange-inert metal ions. (Ethylenediamine)cobalt(III) complexes of imidazole and histidine

Journal Article · Wed Nov 13 00:00:00 EST 1991 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00023a017· OSTI ID:7274068

Rowan-Gordon, N; Nguyenpho, A A; Mondon-Konan, E ^[1]; Turner, A H; Butcher, R J; Okonkwo, A S; Hayden, H H ^[2]; Storm, C B ^[3]

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1. American Univ., Washington, DC (United States)
2. Howard Univ., Washington, DC (United States)
3. Los Alamos National Lab., NM (United States)

(Ethylenediamine)cobalt(III) complexes of imidazole and histidine are nitrated under mild conditions with a standard HNO{sub 3}-H{sub 2}SO{sub 4} nitrating mixture. In contrast to the more robust pentaamminecobalt(III) complexes, the nitrated imidazole ligand readily dissociates, providing an excellent synthetic route to a variety of nitroimidazoles. Pyridine coordinated to either Co(NH{sub 3}){sub 5}{sup 3+} or Co(en){sub 2}Cl{sup 2+} is not nitrated, even under conditions that destroy the complex. The difference in reactivity is evidently a reflection of the Co(III) d electron interaction with the lowest unoccupied molecular orbital (LUMO) of the ligand. The nucleophilic displacement of a nitro group by chloride in a coordinated nitroimidazole is also observed.

• OSTI ID: 7274068
• Journal Information: Inorganic Chemistry; (United States), Vol. 30:23; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COBALT COMPLEXES
CRYSTAL STRUCTURE
HISTIDINE
CHEMICAL REACTION KINETICS
IMIDAZOLES
ABSORPTION SPECTRA
BOND ANGLE
BOND LENGTHS
CHEMICAL SHIFT
LIGANDS
NITRATION
NITRIC ACID
NMR SPECTRA
PYRIDINES
SULFURIC ACID
X-RAY DIFFRACTION
AMINO ACIDS
AZINES
AZOLES
CARBOXYLIC ACIDS
COHERENT SCATTERING
COMPLEXES
DIFFRACTION
DIMENSIONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
KINETICS
LENGTH
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
REACTION KINETICS
SCATTERING
SPECTRA
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties