Diastereomeric meso and rac forms of 1,3-bis(n-propylsulfinyl)propane (BPSP) and 1,2-bis(methylsulfinyl)ethane (BMSE) have been separated and treated with CU(ClO4)(2) to obtain [trans-Cu(meso-BPSP)(2)(H2O)(2)](ClO4)(2) (2) trans-Cu(meso-BMSE)(2)(ClO4)(2) (3) and trans-Cu(rac-BMSE)(2)(ClO4)(2) (4). The configurational assignment to BPSP has been performed by single crystal X-ray analysis, showing that the alpha (m.p. 139.0-139.9 degreesC) and beta (m.p. 107.0-107.6 degreesC) forms correspond to the meso and rac isomers. respectively. Enthalpies of fusion, determined by differential scanning calorimetry techniques, are 34.3 (meso-BMSE), 22.2 (rac-BMSE), 40.6 (meso-BPSP), and 35.1 kJ mol(-1) (rac-BPSP). Single crystals, acceptable for X-ray diffraction studies, were grown by the hanging-drop method of vapor diffusion and micro-seeding techniques. The crystal structure of meso-BPSP.(1) is characterized by an anti conformation of the propane bridge. The two sulfinyl bonds (av. S-O bond distance, 1.487(4) Angstrom) are nearly parallel. In fact, the S --> O vectors form an angle of 2.3 degrees and the pseudo-torsion angle O-S . . .S-O is of 2.2 degrees. Crystals belong to the C2/c space group, with a = 32.285(11), b = 5.315(5), c = 15.232(7) Angstrom, beta = 109.98(3)degrees. The structure was refined to R = 0.092. Crystal data for the copper complexes are space group P2/n, a = 13.914(7), b = 7.834(4), c = 14.805(11) Angstrom, beta = 96.61(5)degrees for 2; space group P2(1)/c, a = 7.348(7), b = 17.892(4), c = 8.620(2) Angstrom, beta = 113.06(2)degrees for 3; space group P2(1)/a, a = 8.343(3), b = 12.337(6), c = 9.390(3) Angstrom, beta = 97.35(3)degrees for 4. The structures were refined to R = 0.066, 0.062, and 0.097 for 2, 3, and 4, respectively. The crystal structures of the meso Cu(II) complexes 2 and 3 are characterized by linear chains of copper atoms, bridged by two disulfoxide molecules acting as bis-monodentate O-ligands. In the rac complex 4, BMSE acts again as a mu (2)-O,O ligand, but forms layers with a net structure containing four copper atoms per mesh, and each layer contains sulfur atoms with both R and S chirality. In the copper complexes the mean S-O bond length is of 1.520(3) Angstrom, confirming the already observed increase in comparison to free sulfoxides. (C) 2001 Elsevier Science BN. All rights reserved.
Stereochemical features of the disulfoxides 1,3-bis(n-propylsulfinyl)propane (BPSP) and 1,2-bis(methylsulfinyl)ethane (BMSE), and their copper(II) complexes. Crystal and molecular structure of meso-BPSP, [trans-Cu(meso-BPSP)(2)(H2O)(2)](ClO4)(2), trans-Cu(meso-BMSE)(2)(ClO4)(2), and trans-Cu(rac-BMSE)(2)(ClO4)(2)
MELCHIOR, Andrea;
2001-01-01
Abstract
Diastereomeric meso and rac forms of 1,3-bis(n-propylsulfinyl)propane (BPSP) and 1,2-bis(methylsulfinyl)ethane (BMSE) have been separated and treated with CU(ClO4)(2) to obtain [trans-Cu(meso-BPSP)(2)(H2O)(2)](ClO4)(2) (2) trans-Cu(meso-BMSE)(2)(ClO4)(2) (3) and trans-Cu(rac-BMSE)(2)(ClO4)(2) (4). The configurational assignment to BPSP has been performed by single crystal X-ray analysis, showing that the alpha (m.p. 139.0-139.9 degreesC) and beta (m.p. 107.0-107.6 degreesC) forms correspond to the meso and rac isomers. respectively. Enthalpies of fusion, determined by differential scanning calorimetry techniques, are 34.3 (meso-BMSE), 22.2 (rac-BMSE), 40.6 (meso-BPSP), and 35.1 kJ mol(-1) (rac-BPSP). Single crystals, acceptable for X-ray diffraction studies, were grown by the hanging-drop method of vapor diffusion and micro-seeding techniques. The crystal structure of meso-BPSP.(1) is characterized by an anti conformation of the propane bridge. The two sulfinyl bonds (av. S-O bond distance, 1.487(4) Angstrom) are nearly parallel. In fact, the S --> O vectors form an angle of 2.3 degrees and the pseudo-torsion angle O-S . . .S-O is of 2.2 degrees. Crystals belong to the C2/c space group, with a = 32.285(11), b = 5.315(5), c = 15.232(7) Angstrom, beta = 109.98(3)degrees. The structure was refined to R = 0.092. Crystal data for the copper complexes are space group P2/n, a = 13.914(7), b = 7.834(4), c = 14.805(11) Angstrom, beta = 96.61(5)degrees for 2; space group P2(1)/c, a = 7.348(7), b = 17.892(4), c = 8.620(2) Angstrom, beta = 113.06(2)degrees for 3; space group P2(1)/a, a = 8.343(3), b = 12.337(6), c = 9.390(3) Angstrom, beta = 97.35(3)degrees for 4. The structures were refined to R = 0.066, 0.062, and 0.097 for 2, 3, and 4, respectively. The crystal structures of the meso Cu(II) complexes 2 and 3 are characterized by linear chains of copper atoms, bridged by two disulfoxide molecules acting as bis-monodentate O-ligands. In the rac complex 4, BMSE acts again as a mu (2)-O,O ligand, but forms layers with a net structure containing four copper atoms per mesh, and each layer contains sulfur atoms with both R and S chirality. In the copper complexes the mean S-O bond length is of 1.520(3) Angstrom, confirming the already observed increase in comparison to free sulfoxides. (C) 2001 Elsevier Science BN. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
