Crystal structures of 2,3-bis(4-chlorophenyl)-1,3-thiazolidin-4-one and trans-2,3-bis(4-chlorophen-yl)-1,3-thiazolidin-4-one 1-oxide

In the crystal structures of the title compounds, C₁₅H₁₁Cl₂NOS, (1), and C₁₅H₁₁Cl₂NO₂S, (2), wherein (2) is the oxidized form of (1), the thiazolidine ring is attached to two chlorophenyl rings. The chlorophenyl ring on the 2-carbon atom position points in the same direction as that of the S atom in (1), while in (2), the S atom points in the opposite direction. The O atom on the chiral S atom in (2) is trans to the chlorophenyl ring on the 2-carbon. The chlorophenyl ring planes in each structure are close to orthogonal, making dihedral angles of 78.61 (6) and 87.46 (8)° in (1) and (2), respectively. The thiazolidine ring has a twisted conformation on the S - C_methine bond in (1), and an envelope conformation with the S atom 0.715 (3) Å out of the plane of other four atoms in (2). In the crystal of (1), molecules are linked by C - H⋯O hydrogen bonds, as well as by slipped parallel π-π interactions [inter-centroid distance = 3.840 (3) Å] between inversion-related phenyl rings, forming sheets parallel to (001). In the crystal of (2), molecules are linked via C - H⋯O and C - H⋯Cl hydrogen bonds, forming slabs parallel to (001).