A mechanistic study of the synthesis, single crystal X-ray data and anticarcinogenic potential of bis(2-pyridyl)selenides and -diselenides

The reaction of bis(organyl)diselenide with a reducing agent, such as LiAlH4, NaBH4, Li(C2H5)(3)BH, etc., generally leads to cleavage of the Se-Se bond resulting in the formation of the corresponding organylselenols/selenolates. However, this work for the first time demonstrates the scisson of the C-(pyridine)-Se bond in bis(2-pyridyl)diselenides with LiAlH4. The reaction affords analytically pure bis(2-pyridyl)selenides in near quantitative yields. The reaction pathway involves the formation of a selenated aluminato complex followed by the scission of the C-(pyridine)-Se bond and generation of LiAlSeH2. The generation of LiAlSeH2 was established by experimental and NMR analysis. The mechanism of the reaction has been supported by theoretical analysis. Single crystal X-ray structure determination of bis(3-methyl-2-pyridyl)selenide (2e) was performed and it shows that the molecules are self-assembled in a 2D-network of CH center dot center dot center dot N hydrogen bonds and pi center dot center dot center dot pi stacking interactions. The synthesized compounds were also evaluated against the Raji cancer cell line (acute lymphoid leukemia).