Heavier chalcogenones (S, Se and Te) of imidazole act as versatile ligands to yield a series of mononuclear and dinuclear bismuth(III)complexes of heavier chalcogenones in excellent yield. These new bismuth heavier chalcogen derivatives are the first structurally characterized molecules, where the bismuth and heavier chalcogen ratio is 1 : 1. There is only one previous report of a crystal structure of a bismuth(III)imidazol selone compound and none with bismuth(III)-imidazol tellone. The bismuth center in monomeric bismuth chalcogen trihalides depicts pseudo trigonal bipyramidal geometry, while the dimeric bismuth chalcogen trihalides demonstrate distorted square pyramidal geometry. The solid state structures of bismuth chalcogenone derivatives feature rare Bi/p(aryl) interactions. Thus, the centroid of the C6-ring suggests a half sandwich type of bismuth environment in mononuclear and dinuclear bismuth(III) chalcogenone complexes. Notably, the Bi/p(aryl) interaction is not often noticed for mononuclear bismuth chalcogen compounds. Some of the bismuth(III) chalcogenone complexes also exhibit C-H/p(aryl), C-H/S and C-H/Cl types of hydrogen bonding. The bismuth-chalcogen bond distance in mononuclear bismuth(III)tribromide chalcogenone complexes is slightly longer than in mononuclear bismuth(III)trichloride chalcogenone complexes. A gradual increase in carbon-chalcogen bond distance was observed from the free imidazole-chalcogenone to mononuclear bismuth(III)trichloride chalcogenones, dinuclear bismuth(III)trichloride chalcogenones and mononuclear bismuth(III)tribromide chalcogenones and dinuclear bismuth(III)tribromide chalcogenones. The UV-vis absorption properties and thermal decomposition properties of imidazol chalcogenones and their bismuth derivatives were investigated. Furthermore, the O-acylative cleavage of cyclic ethers was demonstrated using mononuclear and dinuclear bismuth(III)complexes of heavier chalcogenones as catalysts. In contrast to bismuth(III)trichloride and bismuth(III)tribromide catalysts, mononuclear and dinuclear bismuth(III)complexes of heavier chalcogenones are very active towards an acylative cleavage of cyclic ethers through a mild and regioselective strategy. In particular, mononuclear imidazolthione-bismuth(III)trichloride is very active towards O-acylative cleavage of 2-methyl tetrahydrofuran.

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Thirteen new bismuth(III) dichalcogenone derivatives of triflates and halides were synthesized and structurally characterized. The mono, di, tetra and heptanuclear complexes were isolated with different bismuth(III) coordination environments. These newly isolated bismuth(III)dichalcogenones were characterized by multinuclear NMR, FT-IR, UV-vis, TGA and single crystal X-ray diffraction techniques. These complexes were tested for the synthesis of symmetrical triaryl- or triheteroarylmethanes and the catalysts were found to be highly active. In particular, the selone complexes were relatively more active than thione complexes. Subsequently, the scope of the catalytic reactions was further explored with different substituents.

We present a rare intramolecular Au•••H−C(sp 3 ) hydrogen-bonding interaction and luminescent properties of a gold(I) carbene complex. The Au(I) complex [(L)Au(I)Cl] (1), where L = N-(9-anthracenyl)-N′-(heptyl)benzimidazol-2-ylidene, was prepared, and thermal, emission, and lifetime properties along with a density functional theory study have been considered. X-ray diffraction analysis of single crystals evidenced the solid-state structure of gold complex 1, which exhibited the expected linear coordination geometry. The n-heptane arm of L modulates the hydrogen-bonding interaction between Au(I) and the hydrogen atom of one of the CH 2 moieties. The packing of the gold(I) carbene complex shows an interesting one-dimensional column in the solid state due to intermolecular Cl•••H interactions. The blue emission of 1 in the 400−560 nm region has been tentatively ascribed to arise from intraligand and gold transitions, but the hydrogen-bonding interactions may also make partial contributions.

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