The Phenomenon of Intramolecular Attractive S---O Interactions: Synthesis and Structure of (1,10-Phenanthroline)copper(II) Complexes with Isonitroso-(4-methylthiazol-2-yl)acetamide and Isonitroso-(4-methylthiazol-2-yl)-(benzothiazol-2-yl)methanide

Abstract

Abstract Isonitroso-(4-methylthiazol-2-yl)acetamide H (L1), isonitroso-(4-methylthiazol-2-yl)(benzo-thiazol-2-yl)methanide H(L2) and their copper(II) complexes of composition [Cu(Phen){L1}(ClO4)] (1) and [Cu(Phen){L2}Cl]*C2H5OH (2) have been prepared. Crystal and molecular structures of the complexes have been determined from X-ray diffractioon data (1: monoclinic, space group P21/c, with a = 11.611(2), b = 10.259(2), c = 17.869(4) Å, β = 104.67(3)°, V = 2059.1(7) Å3, Z = 4; R1 = 0.046 for the 2522 unique reflections with I > 2σ(I). 2: triclinic, space group P1̄, with a = 8.351(1), b = 10.876(1), c = 14.891(2) Å, a = 96.170(8)°, β = 94.201(9)°, γ = 106.721(9)°, V = 1280.1(2) Å3, Z = 2; R1 = 0.034 for the 4038 unique reflections with I > 2σ(I)). In the structure of 1 the coordination polyhedron of Cu2+ is a distorted square pyramid with an oxygen atom of the CIO4 counter anion in the apex (C u -O 2.505(3) Å); in complex 2 the copper atom adopts fivefold coordination of a slightly distorted trigonal-bipyramidal geometry with a chlorine atom in the equatorial plane (Cu-Cl 2.3504(9) A). Ethanol of crystallization gives rise to a hydrogen bond at the chlorine atom. In both structures the oximic anions are coordinated to the metal center in a bidentate chelate manner via the nitrogen atom of the nitroso group and the carbonyl oxygen atom (1) or via the benzothiazole nitrogen atom (2) (Cu-O, Cu-N in the range 1.963(2) -2.031 (2) Å). The thiazole group of the ligands takes no part in the coordination. 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) A (2), which may be attributed to a strong intraligand interaction.