Three complexes with same components, PdII, 2-sulfobenzoate and 1,10-phenanthroline, [Pd(phen)2]⋅2(2-Hsb) (1), [Pd(phen)2](2-Hsb)⋅(2-Hsb)⋅2H2O (2), and [Pd(phen)2]⋅[Pd(phen)(2-sb)2]⋅6H2O (3), where 2-H2sb is 2-sulfobenzoic acid and phen is 1,10-phenanthroline, were synthesized and characterized by IR spectra, elemental analyses, thermogravimetric analyses, UV–vis absorption spectra and powder X-ray analysis. Single X-ray crystal structural analyses showed that1and2are ionic species, while3is a dimer through weak bonding interactions. In1and2, 2-Hsb−ligands are partly deprotonated and it is fully deprotonated in3. In2and3there are hydrogen bonds andπ–πinteractions. Extended hydrogen bonding structures for2and3are 1-D and 3-D architectures, respectively. The oxidation of methyl phenyl sulfide by1-3as homogeneous catalysts gave high conversion and selectivity in methanol. The addition of 2-sulfobenzoic acid in the catalytic reaction further promotes the conversion. [ABSTRACT FROM AUTHOR]