Structure and Bonding in Bis(1‐naphthyl) Diselenide and Bis{[2‐( N , N ‐dimethylamino)methyl]phenyl} Tetraselenide, and Their Brominated Derivatives

The formation and crystal structures of bis(1‐naphthyl) diselenide ( 1 ) and bis{[2‐( N , N ‐dimethylamino)methyl]phenyl} tetraselenide ( 2 ) are described. Whereas 1 can be produced in good yields, 2 is formed only as a minor product together with the known main product, bis{[2‐( N , N ‐dimethylamino)methyl]phenyl} diselenide. The composition of the reaction mixture is semi‐quantitatively estimated by 77 Se NMR spectroscopy and DFT calculations. The effect of the n 2 →σ*(Se–Se) and π→σ*(Se–Se) secondary bonding interactions on the Se–Se bonds is discussed both by DFT calculations and comparison with literature, as available. The bromination of 1 yields monomeric (1‐naphthyl)selenenyl bromide ( 3 ) in good yields. That of the reaction mixture of (C 6 H 4 CH 2 NMe 2 )Se x ( x = 2–4) and Se 8 afforded (C 6 H 4 CH 2 NMe 2 H) 2 [SeBr 4 ] ( 4 ) and (C 6 H 4 CH 2 NMe 2 H) 2 [SeBr 6 ] ( 5 ) in addition to (C 6 H 4 CH 2 NMe 2 )SeBr, which has been previously reported.