Diorganodiselenides and zinc(ii) organoselenolates containing (imino)aryl groups of type 2-(RNCH)C6H4

Abstract

Several new diorganodiselenides containing (imino)aryl groups, [2-(RNCH)C₆H₄]₂Se₂ [R = Me₂NCH₂CH₂ (4), O(CH₂CH₂)₂NCH₂CH₂ (5), PhCH₂ (6), 2′,6′-ⁱPr₂C₆H₃ (7)] were obtained by reacting [2-{(O)CH}C₆H₄]₂Se₂ (3) with RNH₂. Treatment of the diselenides 6 and 7 with stoichiometric amounts of K-selectride or Na resulted in isolation of the selenolates K[SeC₆H₄(CHNCH₂Ph)-2] (9) and Na[SeC₆H₄(CHNC₆H₃ⁱPr₂-2′,6′)-2] (10), respectively. The reaction of potassium selenolates with anhydrous ZnCl₂ (2 : 1 molar ratio) gave Zn[SeC₆H₄(CHNCH₂Ph)-2]₂ (11) and Zn[SeC₆H₄(CHNC₆H₃ⁱPr₂-2′,6′)-2]₂ (12). When the dark green solution obtained from diselenide 7 and an excess of Na (after removal of the unreacted metal) was reacted with anhydrous ZnCl₂ a carbon–carbon coupling reaction occurred and the 9,10-(2′,6′-ⁱPr₂C₆H₃NH)₂C₁₄H₁₀ (8) species was obtained. The compounds were investigated in solution by multinuclear NMR (¹H, ¹³C, ⁷⁷Se, including 2D and variable temperature experiments) and by mass spectrometry. The molecular structures of 6, 8, 11 and 12 were established by single-crystal X-ray diffraction. All compounds are monomeric in the solid state. In the diselenide 6 the (imino)aryl group acts as a (C,N)-ligand resulting in a distorted T-shaped coordination geometry of type (C,N)SeX (X = Se). For the zinc complexes 11 and 12 the (Se,N) chelate pattern of the selenolato ligands results in tetrahedral Zn(Se,N)₂ cores.