ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The crystal structure of the orthorhombic, stable phase of 1-chloro-2,4-dinitrobenzene was studied at T=295 K by x-ray diffraction; space group D102h=Pccn; a=893.0(1) pm, b=1104.5(2) pm, c=1567.6(2) pm, Z=8, ρcalc=1.740 Mg m−3, all atoms in position 8(e). The Zeeman split single crystal 35Cl NQR gives e2ΦzzQh−1(35Cl)=74.287(4) MHz, η(35Cl)=0.1636(18) at T=295 K. At 110 K the values are: e2ΦzzQh−1(35Cl)=75.183(4) MHz, η(35Cl)=0.1572(20). Φzz(35Cl) is almost parallel to the bond C(1)–Cl(1) with a deviation of 2.8° from the bond direction. Φxx(35Cl) deviates from the normal to the ring plane by 9.9° and the deviation of Φyy(35Cl) from the ring plane amounts to 8.3°. By high field single crystal NMR the 14N nuclear quadrupole coupling tensors were determined. At T=295 K it is found: e2ΦzzQh−1 (14N(2))=0.9109(10) MHz, η(14N(2))=0.222(3); e2ΦzzQh−1 (14N(4))=1.0758(10) MHz, η(14N(4))=0.303(3). The (NO2)(2) group is twisted 41.9° against the ring plane whereas the group (NO2)(4) is much less twisted to the benzene ring plane (twist angle 12.3°). Both Φzz(14N(2)) and Φzz(14N(4)) are nearly parallel to the bond directions C(2)–N(2) and C(4)–N(4), respectively. In the group (NO2)(4), Φxx(14N) is almost in the plane O(4,1)–N(4)–O(4,2) and parallel to the direction O(4,1)⋅⋅⋅O(4,2). Accordingly, Φyy(14N(4)) is perpendicular to the plane (NO2)(4). Quite differently to the geometrical twist angle of 41.9°, Φxx(14N(2)) is only 22.2° twisted against the benzene ring plane thus forming an angle of 19.7° with the direction O(2,1)⋅⋅⋅O(2,2).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.456499
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