Infrared, ~(119)Sn, ~(13)C and ~1H NMR, ~(119)Sn and ~(13)C CP/MAS NMR and mossbauer spectral study of some tributylstannyl citrates and propane-1,2,3-tricarboxylates

摘要

Six tributylstannyl citrates and three tributylstannyl propane-1,2,3-tricarboxylates of the formula R~1C(CH_2COOR~2)(COOR~3)(CH_2COOR~4) (R~1 = OH or H, R~2, R~3, R~4 = H, Bu_3Sn, C_6H_(11)NH_3, (C_6H_(11))_2NH_2 or (CH_2)_5NH_2) have been synthesised, and their solution and solid-state structures studied by infrared, ~1H, ~(13)C and ~(119)Sn NMR, ~(13)C and ~(119)Sn CP/MAS NMR and ~(119)Sn Mossbauer spectroscopies. In non-coordinating solvents, the compounds exist as isolated molecules or ionic-pairs with their tin atoms in pseudotetrahedral environments. In coordinating solvents, the tin atoms in the compounds are five-coordinate owing to the participation of the solvent in bonding; and their trans-trigonal bipyramidal coordination spheres consist of the ipso-carbon atoms of the butyl substituents in equatorial plane, and the solvent molecule and the oxygen atom of the monodentate carboxyl group in axial positions. A part of tributylstannyl groups together with some bidentate bridging carboxylate groups from polymeric chains in the solid state of citrates and propane-1,2,3-tricarboxylates. Also dioxastanna-rings with the participation #alpha#-hydroxycarboxylate fragments and one of the tributylstannyl groups occur probably in some citrates in the solid state. The spectroscopic assignment for the citrate has been confirmed by crystal structure analysis.