Gas-phase electron diffraction and quantum chemical study of the structure of the 4-nitrobenzene sulfonyl chloride molecule

A combined gas-phase electron diffraction and quantum chemical (B3LYP/6-311+G**, B3LYP/cc-pVTZ, MP2/6-31G*, and MP2/cc-pVTZ) study of the structure of the 4-nitrobenzene sulfonyl chloride molecule is performed. It is found that at a temperature of 391(3) K only one conformer with C s symmetry is present in the gas phase. The following experimental values of structural parameters are obtained: r h1(C-H)av = 1.086(6) A, r h1(C-C)av = 1.395(3) A, r h1(C1-S) = 1.773(4) A, r h1(S=O) = 1.423(3) A, r h1(S-Cl) = 2.048(4) A, r h1(N-O) = 1.224(3) A, r h1(N-C4) = 1.477(3) A, ∠(C1-S=O) = 109.0(4)°, ∠(Cl-S-O) = 106.7(2)°, ∠C1-S-Cl = 100.2(13)°, ∠O=S=O = 122.9(11)°, ∠O=N=O = 123.6(5)°. The C2-C1-S-Cl torsion angle that characterizes the position of the S-Cl bond relative to the benzene ring plane is 89(4)°. The NO2 group lies in the benzene ring plane. Internal rotation barriers calculated by B3LYP/6-311+G** and MP2/6-31G* methods are: V 1 = 4.7 kcal/mol and 5.3 kcal/mol for the sulfonyl chloride group; V 2 = 4.9 kcal/mol and 6.0 kcal/mol for the nitro group.