A series of carboxylate-substituted trinuclear molybdenum cluster compounds formulated as Mo 3S 4(DTP) 3(RCO 2)(L), where R=H, CH 3, C 2H 5, CH 2Cl, CCl 3, R 1C 6H 4 (R 1 is the group on the benzene ring of aromatic carboxylate), L=pyridine, CH 3CN, DMF, have been synthesized by the ligand substitution reaction. The dissociation of the loosely-coordinated ligand L from the cluster core was studied by 31P NMR. The dissociation process of L is related to the solvent, temperature, and acidity of carboxylate groups, so as to affect the solution structure and reactive properties of the cluster. The long-distance interaction between ligands RCO 2 and L is transported by Mo 3S 4 core. A series of carboxylate-substituted trinuclear molybdenum cluster compounds formulated as Mo 3S 4 (DTP) 3 (RCO 2) (L) where R═H, CH 3, C 2H 5, CH 2Cl, CCl 3, R 1C 6H 4 R 1 is the group on the benzene ring of aromatic carboxylate), L = pyridine, CH 3CN, DMF, have been synthesized by the ligand substitution reaction. The dissociation of the loosely-coordinated ligand L was studied by 31P NMR . The dissociation process of L is related to the solvent, temperature, and acidity of carboxylate groups, so as to affect the solution structure and reactive properties of the cluster. The long-distance interaction between ligands RCO 2 and L is transported by Mo 3S 4 core.