The crystal and molecular structures of 3-methyl-4-nitropyridine N-oxide and 3,5-dimethyl-4-nitropyridine N-oxide

Abstract

The crystal structures of 3-methyl-4-nitropyridine N-oxide (M4NPO), tetragonal 3,5-dimethyl-4-nitropyridine N-oxide (D4NPO-T) and orthorhombic D4NPO (D4NPO-O) have been determined. M4NPO is ortho-

2-Phenylquinazoline 1,3-dioxide

“…These facts suggest a greater contribution to the resonance structure by canonical forms such as (II). This is in agreement with the findings of Shiro, Yamakawa & Kubota (1977) who investigated a series of substituted pyridine Noxides. 2-PHENYLQUINAZOLINE 1,3-DIOXIDE close contacts, the molecular packing being due to van der Waals forces only.…”

Structure of a 1:1 addition compound of mercuric bromide with 3-methyl-4-nitropyridine 1-oxide

“…Despite the larger standard deviations, it can still be seen that the N1---O7 bond length (1.340/~) is obviously longer than that (1.292/~) in the free ligand (Shiro, Yamakawa & Kubota, 1977), and the C---C bonds parallel to the longer molecular axis have the same bond lengths as other C--C bond lengths within the standard deviations. These indicate that when the ligand takes part in coordination the contribution of the quinoid structure to the resonance forms is the least significant, in contrast to the free ligand.…”

“…The twist angle between the nitro group and the pyridine plane is 20.1 ° , which is larger than that of 16.7 ° in the free ligand. According to Shiro, Yamakawa & Kubota (1977), there are two factors which influence the twist angle. The first is the steric effect of the methyl group substituted at vicinal positions, which can be seen from a comparison between the twist angle of free 2-methyl-4-nitropyridine 1-oxide [4.9 ° (Li, Liu, Wu, Shi & Hu, 1987)] and that of the title ligand.…”

Electrostatic modeling of the linear optical susceptibilities of 2-methyl-4-nitroaniline, m-nitroaniline, 3-methyl-4-nitropyridine N-oxide and 2-carboxylic acid-4-nitropyridine-1-oxide crystals

“…2, we sketched the molecular structures and gave specific bond lengths. The crystal structure and molecular geometry of MNA, mNA, POM, and POA were taken from the work of Ferguson et al [40], Ploug-Sorensen and Andersen [41], Shiro et al [42], and Wu et al [33], respectively. It should be noted that the crystal structure data are used without geometry re-optimization.…”