Structural chemistry of organotin carboxylates: XVII. Diorganotin(IV) derivatives of N-phthaloyl-dl-valine

Abstract New diorganotin(IV) complexes of the general formula [R 2 Sn(A) 2 ] and {[R 2 Sn(A)] 2 O} 2 (where A is the anion derived from the N -phthaloyl derivative of dl -valine and R  Me, n Bu and n Oct) have been prepared and characterized by spectroscopic methods and in the case of the {[Me 2 Sn(A)] 2 O} 2 compound, by X-ray crystallographic methods. The Sn atoms in the [R 2 Sn(A) 2 ] complexes are six-coordinate and the {[R 2 Sn(A)] 2 O} 2 complexes are examples of dicarboxylato tetraorganodistannoxanes. The crystal structure of {[Me 2 Sn(A)] 2 O} 2 shows both the endocyclic and exocyclic Sn atoms to be five-coordinate, trigonal bipyramidal. Several weak intramolecular contacts are noted with the most noteworthy being a contact of 3.15(1) A between the imido CO atom and the endocyclic Sn atom.