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⋯π(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⋯π(aryl) interaction is not often noticed for mononuclear bismuth chalcogen compounds. Some of the bismuth(III) chalcogenone complexes also exhibit C–H⋯π(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.

The syntheses and structures of copper(I) chalcogenone complexes are described. The homoleptic mononuclear copper(I) complexes [(IPrE)₂Cu]ClO₄, IPrE, 1,3-bis(2,6-diisopropylphenyl)imidazoline-2-thione (1) and 1,3-bis(2,6-diisopropylphenyl)imidazoline-2-selone (2); [(IMesE)₂Cu]ClO₄, IMesE, 1,3-bis(2,4,6-trimethylphenyl)imidazole-2-thione (3) and 1,3-bis(2,4,6-trimethylphenyl)imidazole-2-selone (4); [(IPrE)₂Cu]BF₄, E = S (5); E = Se (6) and [(IMesE)₂Cu]BF₄, E = S (7); E = Se (8) are formed from the reduction of copper(II) to copper(I) with the corresponding imidazoline-2-chalcogenones. X-ray structure analyses of seven compounds (1–3 and 5–8) show that the copper(I) ion is in a perfect linear coordination, while 4 is in quasi-linear geometry. Molecules 2, 4, 6 and 8 are the first structurally characterized homoleptic copper(I) selone complexes. The optical and thermal properties of imidazoline-2-chalcogenones and their copper(I) derivatives are investigated. These complexes are able to act as catalysts in regioselective borylation of numerous unsymmetrical alkynes, yielding synthetically useful vinylboronates. Among catalysts 1–8, catalyst 4 is highly selective towards the regioselective boron addition of 1-phenyl-1-propyne.

Thirteen new bismuth(iii) dichalcogenone derivatives with diversified structural motifs were successfully isolated and used as potential catalysts for the synthesis of triaryl- or triheteroarylmethanes.

The first mesoionic heavier chalcogenones, L¹–L³ [L¹ = 1-(2-mesitylene)-3-methyl-4-phenyltriazolin-5-selone; L² = 1-(2-mesitylene)-3-methyl-4-phenyltriazolin-5-thione; L³ = 1-(benzyl)-2-3(methyl)-4-phenyltriazolin-5-selone], were isolated and characterised. Density functional theory was used to obtain insights into the σ donor and π accepting nature of mesoionic chalcogenones. Using these new ligands, a series of the first zinc(II) mesoionic chalcogenone complexes were isolated. Three mono nuclear zinc(II) chalcogenone complexes, [(L¹)Zn(Cl)₂(HOMe)] (1), [(L²)Zn(Cl)₂(HOMe)] (3) and [(L²)Zn(Br)₂(HOMe)] (4), and two dinuclear zinc complexes, [(L¹)Zn(Br)(μ²-Br)]₂ (2) and [(L³)Zn(Br)(μ²-Br)]₂ (5), containing mesoionic thione and selone ligands were synthesized and characterised. These new complexes 1–5 represent the first structurally characterized mesoionic chalcogenone supported metal derivatives. Furthermore, all zinc complexes were characterized by thermogravimetric analysis and UV-vis spectroscopy. The solid-state structures of all zinc complexes were determined by single-crystal X-ray diffraction. The catalytic activities of the zinc(II) complexes in thioetherification reactions were investigated without scrubbing of oxygen. The scope of the catalytic reactions was explored with a wide range of thiophenols and aryl halides. The diaryl thioethers were obtained in very good yield under mild conditions. The present protocol furnishes a synthetic route for the C–S cross-coupling of thiophenols and aryl halides without scrubbing oxygen and moisture.

The first comparative study of C, S, Se and P donor ligands-supported copper( i ) complexes for C–N and C–Si bond formation reactions.

Zinc and cadmium imidazoline selone complexes were synthesized and demonstrated to be potential catalysts for Barbier coupling in aqueous alcohol media.