The selective 6-endo-dig cyclization reaction of alkynyl aryl ketones with electrophilic organochalcogen species in the presence of Selectfluor® is described.

A monoselenoether ligand (PySeCH₂Py) reacts with Co^II, Cu^II, Cu^I and Pd^II resulting in the formation of molecular, polymeric or cyclometallated complexes depending on the starting material used and the reaction conditions applied.

This work is focused on the solvothermal synthesis, characterization, and photocatalytic activities of the first organically linked Zn^II hydrogenselenite coordination polymers.

Reactions between 3-amine-2-((pyridin-2-ylmethyl)selanyl)pyridine (L) and MX₂ (M = Co, Cu, Zn; X = Cl, Br) result in the formation of the metal(II) molecular complexes 1–5 with the general formula [MX₂(L)]. The organic ligand is coordinated to the metal center through nitrogen atoms of the pyridine rings, without interaction with the selenium atom. The rhenium(V) complex [ReO(apySe)₂]Cl (6) is formed in two different ways, using [ReOCl₃(PPh₃)₂] as precursor. Firstly, the formation of 6 was observed in the mother liquor, through C_sp³–Se bond cleavage of the ligand L and formation of new Re–Se bonds. Secondly, the direct reaction between bis(3-amino-2-pyridyl)diselane (apySe)₂ and [ReOCl₃(PPh₃)₂] gave complex 6 in higher yields. The coordination compounds were characterized by spectroscopic and crystallographic methods. Furthermore, the antibacterial activity of the complexes 1–5 was evaluated against Gram-positive bacteria, Staphylococcus aureus (ATCC® 25923), and Gram-negative bacteria, Escherichia coli (ATCC® 25922). The results suggest that the complexes [CoCl₂(L)] (1), [CuCl₂(L)] (3), [CuBr₂(L)] (4) and, [ZnCl₂(L)] (5) possess significant bactericidal activity when compared with those of the free ligand and metal salts used in the synthesis.