New hexacyclic binuclear tin complexes derived from bis-(3,5-di-tert-butyl-2-phenol)oxamide

The syntheses of bis-(3,5-di-tert-butyl-2-phenol)oxamide (2a) and four new hexacyclic bimetallic tin compounds derivatives are reported: bis-(3,5-di-tert-butyl-2-oxo-phenyl)-oxamido-bis(dibutyltin) (3), bis-(3,5-di-tert-butyl-2-oxo-phenyl)-oxamido-bis-(diphenyltin) (4), bis(triethylammonium) bis-(3,5-di-tert-butyl-2-oxo-phenyl)-oxamido-bis-(dichlorobutyl-stannate) (5), and bis-[(OSn) ethanol]-bis-(3,5-di-tert-butyl-2-oxo-phenyl)-oxamido-bis-(chlorophenyltin) (6). All tin compounds show a planar ligand skeleton in which each tin atom is linked to the phenoxy group, to the anilinic nitrogen atom and to the oxygen of the oxamide group. Compounds 3 and 4 have two pentacoordinated diorganyl tin atoms with a distorted bpt geometry, whereas 5 contains a dianionic structure with two hexacoordinated tin atoms bonded to a n-butyl group and to two chlorine atoms and two triethyl ammonium as counterions. Compound 6 has two hexacoordinated tin atoms, each atom is bonded, in addition to the ligand, to one phenyl and one chlorine and coordinated to an ethanol molecule. Characterization of the compounds was made through usual analytical and spectroscopic methods. Structures of 4,6-di-tert-butyl-1-phenol-2-amine 1, the oxamide 2a and the four tin compounds 3–6 were established by the X-ray diffraction analyses.