3-(2-Methylphenyl)-2-selenoxo-2,3-dihydroquinazolin-4(1H)-one and Its Complex with Cd(II): Synthesis and Molecular and Crystal Structures

The reaction of methyl anthranilate with 2-methylphenyl-iso-selenocyanate in boiling absolute ethanol affords a new compound: 3-(2-methylphenyl)-2-selenoxo-2,3-dihydroquinazolin-4(1Н)-one (HL). Free ligand HL, which is selone, is preliminarily transformed into the corresponding sodium selenolate [C₁₅H₁₁N₂OSeNa] (I), which is then used without isolation in the reaction with cadmium chloride. This reaction leads to the formation of complex [Cd₂(μ-L)₂(L)₂(C₂H₅OH)₂] (II). The structures of the compounds are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2142342 (НL) and 2246014 (II)) and NMR spectroscopy (¹Н, ¹³С, ¹⁵N, and ⁷⁷Se). In the crystal, the molecules of HL form one-dimensional chains due to H…O and H…Se contacts and alternate in the syndiotactic order. Compound II is the centrosymmetric binuclear complex [C₆₄H₅₆Cd₂N₈O₆Se₄]. The cadmium atoms in complex II are hexacoordinated by two chelate anionic ligands L^–. According to the NMR data, in a DMSO-d₆ solution free ligand HL has the selone structure, whereas in cadmium complex II this ligand exists in the selenolate form, which is consistent with the XRD data on the crystal structures of the compounds.