Di-n-but­yl{1-[1-(2-hydroxy­phen­yl)ethyl­idene]-5-[1-(2-oxidophen­yl)ethyl­idene]thio­carbazonato-κ3 O 5,N 5,S}tin(IV)

The 'symmetrical' 1,5-bis-[1-(2-hydroxy-phen-yl)ethyl-idene]thio-carbazone Schiff base condenses with dibutyl-tin oxide to form the title complex, [Sn(C(4)H(9))(2)(C(17)H(16)N(4)O(2)S)], in which the deprotonated ligand O,N,S-chelates to the Sn atom of two crystallographically independent mol-ecules. The ligand bears a formal negative charge on the S and one O atom; the other O atom retains its H atom. The Sn atoms are five-coordinated in a cis-C(2)NOSSn trigonal-bipyramidal environment, and the apical sites are occupied by the O and S atoms. In both mol-ecules, the hydr-oxy group is hydrogen bonded to a double-bonded N atom, generating a six-membered ring. The amino group is a donor to the coordinated O atom of an adjacent mol-ecule, the hydrogen-bonding inter-action giving rise to a helical chain running along the b axis. In one of the independent mol-ecules, the atoms of one of the n-butyl groups are disordered over two sets of sites with equal occupancy. In the other independent mol-ecule, the atoms of both n-butyl groups are disordered over two sets of sites with equal occupancy and, in addition, the Sn and S atoms were also refined as disordered over two sets of sites with equal occupancy.