Metal Complexes of 1-Oxa-4,7-dithiacyclononane.

The ligand 1-oxa-4,7-dithiacyclononane (L) and its complexes [Pd(L)Cl(2)], [Cu(L)(2)][ClO(4)].CH(3)CN, [Cu(L)Br](2), and [Co(L)(2)][ClO(4)](2).2CH(3)NO(2) have been prepared. Crystal data are as follows. For monoclinic [Pd(L)Cl(2)], C(6)H(12)Cl(2)OPdS(2): space group P2(1)/n; a = 8.464(2), b = 12.199(2), c = 10.384(2) Å; beta = 105.09(1) degrees; Z = 4; R = 0.024, R(w) = 0.033 for 1721 reflections. For monoclinic [Cu(L)(2)][ClO(4)].CH(3)CN, C(14)H(27)ClCuNO(6)S(4): space group P2(1)/n; a = 7.743(2), b = 19.515(5), c = 15.017(2) Å; beta = 102.85(2) degrees; Z = 4; R = 0.036, R(w) = 0.038 for 3124 reflections. For triclinic [Cu(L)Br](2), (C(6)H(12)BrCuOS(2))(2): space group P&onemacr;; a = 7.809(5), b = 8.880(3), c = 7.567(2) Å; alpha = 92.44(3), beta = 102.85(2), gamma = 99.30(4) degrees; Z = 2; R = 0.027, R(w) = 0.027 for 1494 reflections. For monoclinic [Co(L)(2)][ClO(4)](2).2CH(3)NO(2), C(14)H(30)Cl(2)CoN(2)O(14)S(4): space group P2(1)/c; a = 10.333(3), b = 14.293(6), c = 9.365(4) Å; beta = 100.89(3) degrees; Z = 2; R = 0.067, R(w) = 0.058 for 1517 reflections. The ligand displays a variety of conformations in these structures. The palladium complex does not undergo 1,4-heteroatom binding site fluxional processes but does dissociate in dimethyl sulfoxide. An apical Pd.O (2.968(3) Å) interaction has been detected by both NMR and X-ray studies. The Cu(I) cation is tetrahedral with a [2+2] mode of ligand coordination. [Cu(L)Br](2) involves two Br bridges between coppers and two thioether sulfurs from a ligand to complete each copper's tetrahedral coordination sphere. Surprisingly, the cyclic voltammetric behavior of the copper complexes is similar to that of 1,4,7-trithiacyclononane complexes. The cation [Co(L)(2)](2+) is pseudooctahedral with nearly regular angles at cobalt but a long (2.235(6) Å) Co-O bond due to Jahn-Teller distortion. The complex [Co(L)(2)][ClO(4)](2) is magnetically dilute and low-spin over the temperature range 5-292 K.