Coordination of 2,2'-Bithiazole. Spectral, Magnetic and Structural Studies of the Iron(II) and Nickel(II) Complexes

Abstract

Iron(II) and nickel(II) complexes of 2,2′bithiazole (2bt) have been prepared. Salts of [Fe(2bt)3]2+ have spectral properties typical of iron(II) diimine systems. Their magnetic and Mossbauer spectral properties show an anomalous temperature-dependence which is associated with a temperature-induced singlet (1A1) ↔ quintet (5T2) transition. The manifestation of the spin transition is complicated by the existence of two modifications of the complex perchlorate. In one of these there is a relatively small fraction of quintet state species in an essentially low-spin lattice. This fraction increases only slightly at elevated temperatures within the range 89-343 K. The other modification is essentially high-spin at high temperatures and low-spin at low temperatures. The quadrupole splitting values for the two high-spin species are quite different, arising from different lattice contributions. The structures of 2bt and the related 4,4′-bithiazole and of [Ni(2bt)3][ClO4]2 have been determined by single-crystal X-ray diffactometry. These afford a comparison of the coordination features of the isomeric bithiazoles. 2,2′-Bithiazole, orthorhombic with space group P bca , Z = 8, α 9.284(1), b 14.564(1), c 10.802(1) Ǻ; 4,4′-Bithiazole, monoclinic with space group P21/c, Z = 2, a 5.528(2), b 6.288(2), c 11.316(4)Ǻ. The nickel complex, orthorhombic with non-centrosymmetric space group Pna21, four molecules per unit cell, a 16.709(3), b 9.511(4), c 17.491(2)Ǻ, has a stacking fault which reduces the intensity of h = 2n+1 data. Pseudosymmetry enables data with h = 2n to be described by a disordered structure in the centrosymmetric space group Pnmn.

Synthesis, characterization, mechanochromism and photochromism of [Fe(dm4bt)3][FeCl4]2 and [Fe(dm4bt)3][FeBr4]2, along with the investigation of steric influence on spin state

“…49,50 Furthermore, the magnetism of low spin tris Fe(II) complexes with unsubstituted bithiazole ligands, [Fe(2bt) 3 ] +2 is affected by anions. 12 However, in the titled compounds, spin state and overall pattern of magnetic behavior upon cooling are similar, because of the similarity of their structures ( Fig. 1 and 2) but they exhibit some differences.…”

Synthesis, characterization, and crystal structural study of the iron(II) 4,4′-bithiazole complex [Fe(C6H4N2S2)3]2+(NO3 −)2

“…There are only a few reports in the literature on coordination compounds of Fe(II) with bithiazole [15][16][17][18]. Here we report the synthesis and characterization of an iron complex with 4,4 0 -bithiazole (4,4 0 -bit).…”

An investigation of electronic structure and properties of new chromophore: 3,3′-bithiazolo[3,4-a]pyridinium perchlorate

“…Similarly, thiazole ligands are also investigated in trans-platinum drugs for antitumor effects [4]. Moreover, 2,2 0 -bithiazoles have been studied for their coordination behavior in iron(II) and nickel(II) complexes [5] and alkyl bithiazole oligomers have recently been tested for organic electronic applications [6,7]. In particular, we now consider the extension of monocyclic heterocycles to bicyclic systems.…”