Synthesis,Structural Characterization And Properties Of Organotin Complexes Derived From Sulfamoyl Carboxylic Acids

In recent years,the study of organometallic complexes is becoming one of the hotpots in inorganic,medicinal and biomedical chemistry research.The organotin???complexes,as an indispensable component of organometallics,have been extensively investigated owing to their structural diversities and effective biological activities,particularly potential candidates for cancer chemotherapy.In the process of biological activity research and screening,the researchers were pleasantly surprised to find out that some organotin???complexes,especially organotin???complexes based on carboxylic acid,phosphoric acid and phosphoric acids,and sulfonic acid,showed higher selectivity.Therefore,the metal complexes have great potential to be investigated for enhancing or optimizing the effect in biological activity.Although a large number of antibiotics have been introduced,sulfonamides,as one of the antibacterial drugs,are still important antibacterial chemotherapeutic drugs because sulfonamides have the characteristics of broad antibacterial spectrum and stable nature.In recent years,many studies have shown that except antibacterial activity,some sulfonamide complexes exhibited higher activity against cell proliferation.The main functional group of the sulfonyl compound,-SO₂NH₂,with two proton acceptors and two proton donors,will play an important role in the construction and stabilization of the supramolecular structure.Based on the above considerations and the principle of combinatorial chemistry,we selected carboxybenzenesulfonamide as ligands,bearing the carboxylate group and aminosulfonyl group,to synthesize a series of organotin???complexes,which are expected to enhance or optimize biological activity of organotin???complexes.This paper introduces the synthesis of organotin???complexes based on carboxybenzenesulfonamide,and studies the structure and properties of these complexes in detail.The main works of the research are displayed as below.1.We selected 4-carboxybenzenesulfonamide as ligand,which bears the carboxylate group and aminosulfonyl group,to synthesize six organotin???complexes 1-6 from the reactions of 4-carboxybenzenesulfonamide with the corresponding triorganotin???chloride or diorganotin???oxide.The six novel organotin???complexes were prepared and characterized by X-ray diffraction and analysis of the non-covalent intermolecular contacts in all complexes reveals the existence of the supramolecular interactions.Furthermore,complexes 1-5 were evaluated for their in vitro cytostatic activity against hepatocellular carcinoma cell lines and cervical carcinoma cell lines.The results indicated that:?1?a 1:1 ratio reaction of triorganotin???chloride with ligand4-carboxybenzenesulfonamide obtained mononuclear tin???monomer.?2?a reaction of diorganotin???oxide with ligand 4-carboxybenzenesulfonamide in 1:2 molar ratio afforded tetranuclear tin???ladder-like structures.Furthermore,the in vitro cytotoxicity investigation of all complexes except complex 6?lower solubility in DMSO solvent?were carried out by MTT-based assays.The obtained results presented that three organotin???complexes 2,3,5 exhibit outstanding inhibitory efficiency than cisplatin.It's worth noting that phenyltin???complex 3 exihibits significant difference in inhibitions against the two cell lines,indicating that phenyltin???complex 3 presents a certain degree of specificity.2.We selected 4-?dipropylsulfamic acid?benzoic acid as ligand,and have investigated on the reactions of the ligand with dimethyltin???oxide or di-n-butyltin???oxide at different stoichiometric ratio and in different reactive solvents.Four novel organotin???complexes 7-10 were prepared and characterized by X-ray diffraction and the complexes were further evaluated for their in vitro cytostatic activities against human cervical carcinoma cell lines?HeLa?.The results indicated that:?1?a 1:2 stoichiometric ratio reaction of ligand with diorganotin???oxide obtaines tetranuclear tin???ladder-like structure containing two deprotonated ligands linked by three alternate Sn₂O₂four-membered rings.The ligand of the complexes 7 and 8 both adopt monodentate coordination mode.?2?a reaction of diorganotin???oxide with ligand in 1:1stoichiometric ratio to afford tetranuclear tin???ladder-like structure containing two deprotonated ligands.The carboxylates of the complex 9 adopts bidentate coordination mode,while that of the complex 10 adopts both monodentate coordination mode and bidentate coordination mode.The in vitro cytotoxicity investigation of complexes 7-10against human cervix cell lines?HeLa?,was carried out with MTT-based assays.The pilot study has confirmed that three organotin complexes 8 and 10 exhibit outstanding inhibitory efficiency than complexes 7 and 9.Additionally,the antimicrobial activity investigation of complexes 7-10 against E.coli also was proceed through Test tube method,and the result indicates that complexes 8 and 10 exhibit high antimicrobial activity.3.Based on the above studies,we also introduced the N-donor ligand,4,4'-bipyridine,by employing a slow diffusion procedure.Six novel organotin???complexes 12-17 were prepared and characterized.The analysis revealed that:?1?the reactions of ligand4-carboxybenzenesulfonamide with triorganotin???chloride and 4,4-bipyridine at certain molar ratio obtain complexes 12 and 13.?2?a reaction of ligand with triorganotin???chloride and 4,4'-bipyridine in 2:2:1 molar ratio afford complexes 14 and 15.X-ray diffraction discloses that the organotin???complexes 12-15 are all centrally symmetric monomer structures,and the N-ancillary ligands are located at the center of symmetry.It is worth mentioning that the two pyridine ring male planes of 4,4'-bipyridyl in complexes12-15 show a strong conjugation between the pyridine rings.The analysis of structures of all complexes reveals the N-donor ligands 4,4'-bipyridine and aminosulfonyl groups play a significant role in the formation of these complexes and stabilization of supramolecular structures.In addition,we selected complexes 13 and 15 as quencher to investigate the binding experiments with BSA.The results showed that complexes 13 and 15 exhibited stronger complexation.