The synthesis and spectroscopic characterization (infrared, H-1, C-13, Sn-119 NMR and Sn-119 Mossbauer) of three organotin derivatives incorporating carboxylate ligands, with general formulae (C6H11)(2)CHCOOSnPh3 (1), (CH3NH)C6H4COOSnPh3 (2) and 3,5-(NO2)(2)C6H4CO2SnMe3 (3) are reported together with their X-ray crystal structures. The compounds were obtained by the condensation, in ethanol, of the appropriate carboxylic acid with triphenyltin hydroxyde (1, 2) or trimethyltin hydroxide (3). In the case of triphenyltin(IV) derivatives, 1 and 2, the values of the Mossbauer quadrupole splitting and the infrared data [Deltav = (v(as)(O-C=O) -v(s)(O-C=O)) > 230 cm(-1)] are consistent with the presence of monomeric species in the solid state. X-ray crystallographic analysis confirms their structures as consisting of monomeric species, featuring distorted tetrahedral environments around the tin atoms. In both structures, one CSnC angle is relatively opened compared with the two others, which may be linked to the relatively close approach of the non-bonding oxygen of the carboxylate ligand to the tin center (Sn(1) - O(2) = 2.659(1) Angstrom and 2.773(1) Angstrom in 1 and 2 respectively). NMR data show the presence of monomeric species in solution, as found in the solid state. A significant intramolecular hydrogen bond is noticed between the hydrogen atom of the N-methylanthranilate ion and the non-coordinating oxygen atom in 2 (H(1A)-O(2) = 2.06 Angstrom, N(1)-H(1A)-O(2) = 132 degrees). Infrared and Mossbauer spectroscopy and X-ray diffraction have shown that 3 has an infinite chain structure in which the central tin atom adopts a distorted trigonal bipyramidal coordination with two oxygen atoms in axial positions, the three carbon atoms of the methyl group occupying equatorial sites. The 3,5-dinitrobenzoate anions act as bidentate bridging ligands and the SnC3 moieties are asymmetrically trans-coordinated (Sn-O(1) and Sn-O(2): 2.181(1) and 2.501(2)). C-13 and Sn-119 NMR data reveal a cleavage of the infinite chain structure of 3 in solution; the 119Sn chemical shift value (124.0 ppm), in conjunction with the magnitude of the coupling constant [(2)J(Sn-119-C-H) = 58.8 Hz; (1)J(Sn-119-C) = 393.6Hz], is consistent with a tetrahedral environment around the tin center. Copyright (C) 2004 John Wiley Sons, Ltd.