THE PHENOMENON OF INTRAMOLECULAR ATTRACTIVE S-CENTER-DOT-CENTER-DOT-CENTER-DOT-O INTERACTIONS - SYNTHESIS AND STRUCTURE OF (1,10-PHENANTHROLINE)COPPER(II) COMPLEXES WITH ISONITROSO-(4-METHYLTHIAZOL-2-YL)ACETAMIDE AND 4-METHYLTHIAZOL-2-YL)-(BENZOTHIAZOL-2-YL)METHANIDE

Isonitroso-(4-methylthiazol-2-yl)acetamide H(L-1), onitroso-(4-methylt hiazol-2-yl)(benzothiazol-2-yl) methanide H(L-2) and their copper(II) complexes of composition [Cu(Phen){L-1}(ClO4)] (1) and [Cu(Phen){L-2}C I]C2H5OH (2) have been prepared. Crystal and molecular structures of the complexes have been determined from X-ray diffraction data(1: mono clinic, space group P2(1)/c, with a = 11.611(2), b = 10.259(2), c = 17 .869(4) Angstrom, beta = 104.67(3)degrees, V = 2059.1(7) Angstrom(3), Z = 4; R1 = 0.046 for the 2522 unique reflections with I > 2 sigma(I). 2: triclinic, space group P (1) over bar, with a = 8.351(1), b = 10.8 76(1), c = 14.891(2) Angstrom, alpha = 96.170(8)degrees, beta = 94.201 (9)degrees, gamma = 106.721(9)degrees, V = 1280.1(2) Angstrom(3), Z = 2; R1 = 0.034 for the 4038 unique reflections with I>2 sigma(I)). In t he structure of 1 the coordination polyhedron of Cu2+ is a distorted s quare pyramid with an oxygen atom of the ClO4 counter anion in the ape x (Cu-O 2.505(3) Angstrom); in complex 2 the copper atom adopts fivefo ld coordination of a slightly distorted trisonal-bipyramidal geometry with a chlorine atom in the equatorial plane (Cu-Cl 2.3504(9) Angstrom ). Ethanol of crystallization gives rise to a hydrogen bond at the chl orine atom. In both structures the oximic anions are coordinated to th e metal center in a bidentate chelate manner via the nitrogen atom of the nitroso group and the carbonyl oxygen atom (1) or via the benzothi azole nitrogen atom (2) (Cu-O, Cu-N in the range 1.963(2)-2.031(2) Ang strom). The thiazole group of the ligands takes no part in the coordin ation. The nitroso oxygen atoms possess short intramolecular contacts with thiazole sulphur atoms, with d(S---O) at 2.605(3) (1) and 2.676(3 ) Angstrom (2), which may be attributed to a strong intraligand intera ction.