Isomers and isomerization reactions of four nitro derivatives of methane

✍ Scribed by Chaoyang Zhang; Xiaolin Wang; Mingfei Zhou

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 890 KB
• Volume: 32
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/jcc.21762

✦ Synopsis

The nitro, nitrite, and aci-form isomers and the isomerization reactions of mono-, di-, tri-, and tetranitromethanes (NMs) were computationally investigated. The results show that the isomerization displacement of NO 2 by ONO groups is surprisingly thermodynamically favored for the di-, tri-, and tetra-NMs. The molecular stability decreases and the isomerization becomes easier by increasing nitro groups. The largest attraction among substitutes takes place through the central carbon atom in C(ONO) 4 and leads to its higher stability than the C(NO 2 ) 4 isomer. There is a concerted change of the COÀ ÀNO, CÀ ÀONO, and CONÀ ÀO bonds in the nitrite isomers, that is, the weakened COÀ ÀNO bond is accompanied with the strengthened CÀ ÀONO and CONÀ ÀO bonds, and vice versa. We only succeeded in finding two tight transition states of isomerization reactions from NO 2 to ONO in the monoand di-NMs, whereas isomerization reactions to the aci-forms through an intramolecular hydrogen transfer can always be found.