The X-Ray Structures of Sulfoxides.

Abstract  We have structurally characterized and investigated a range of sulfoxide compounds containing aryl and alkyl substituents. Compounds 1 and 3–6 all crystallize in an orthorhombic space group, where compounds 2 and 7 crystallize in a monoclinic space group. The unit cell parameters of the compounds are as follows: 1 (Fdd2), a = 17.653(5) Å, b = 53.153(14) Å, and c = 10.071(3) Å; 2 (P2 1 /c), a = 7.894(13) Å, b = 5.653(10) Å, and c = 27.02(5) Å, β = 97.347(15)°; 3 (P2 1 2 1 2 1 ), a = 5.7569(6) Å, b = 12.2139(12) Å, and c = 17.5974(18) Å; 4 (Pca2 1 ), a = 8.256(4) Å, b = 5.470(3) Å, and c = 23.995(13) Å; 5 (P2 1 2 1 2 1 ), a = 5.848(4) Å, b = 7.568(5) Å, and c = 27.650(17) Å; 6 (Pbca), a = 10.0569(15) Å, b = 9.9403(16) Å, and c = 17.843(3) Å; and 7 (Pc), a = 13.217(4) Å, b = 5.3766(14) Å, and c = 8.370(2) Å, β = 90.673(6)°. The S=O bond distances in these compounds range from 1.489(7) to 1.515(8) Å. In all seven structures, the O(1)–S–C bond angles vary from 105.1(4) to 111.7(30)° and the C(1)–S(1)–C(11) bond angles range from 94.1(4) to 100.56(12)°. The compounds contain unique intra- and intermolecular interactions depending on the groups attached to the sulfoxide moiety. The polarity of the sulfoxide bond in these compounds allows for intramolecular S···O interactions to occur. When the sulfur is bound to alkyl groups, there tends to be a shorter S···O intermolecular distance than when the sulfur is bound to aromatic substituents. Additionally, if the sulfur is flanked by an aryl group, the S–C bond distance is slightly shorter than if flanked by an alkyl group, suggesting a possible weak O···Haryl intramolecular interaction, weak conjugation of the aromatic ring with the S–O bond or both. Furthermore, if the sulfur is flanked by an alkyl group, a CH2 proton of S–CH2–R can be properly oriented to participate in an intermolecular hydrogen bond with the sulfoxide oxygen of another molecule. Index Abstract  We have structurally characterized and investigated a range of sulfoxide compounds containing aryl and alkyl substituents that contain unique intra- and intermolecular interactions depending on the groups attached to the sulfoxide moiety. [ABSTRACT FROM AUTHOR]