Syntheses, Characterization And X-diffraction Structural Analyses Of Mono-, Di- And Triorganotin(Ⅳ) Derivatives From Hydrazone Schiff-base Ligands

Organotin compounds, as important organometallic chemicals, have shown a variety oftechnical applications as insecticides, bactericides, acaricides, catalysts, plastic stabilizers,wood preservatives, antifouling agents etc.. In early 1980's, there has been increased interestin studying their application on the anti-tumour medicines. Some organotin compoundsdisplayed obvious effects to prevent many tumour cells from growing up. As a result, theiranti-tumour activity is more 100 times than those of the cis-platinum complexes. Moreover,the influence of the structural features of organotin compounds on the anti-tumour activityhas received considerable attention. With the development of X-diffraction technique and itsapplication in structure chemistry, organotin(IV) chemistry boomed unprecedentedly. Basedon these X-diffraction data, scientists are able to have a more intuitionistic observation anddeeper perspective of the organotin(IV) compounds as well as to find more potentialapplications of the organotin(IV) compounds.In the early of 1970s', it is reported by Hodnett that compounds with Schiff base C=Nbonds have some anti-tumour activities, and the activity of organometallic compounds withSchiff base ligands will be more obvious. Also organotin(IV) Schiff bases compounds havemore obvious antitumor activities. Therefore studying these compounds has more meaningsin synthesis, characterization, pharmaceutics and other theory and application researchesother than in structure. Out of above considerations, we carried out a series of research onsyntheses and characterization of organotin(IV) derivatives from hydrazone Schiff-baseligands. The structures and formations of compounds were determined by elemental analysis,IR, 1H NMR spectra and X-ray single crystal diffraction,and the processes and mechanismsof the reactions were presumed. The main contributions of the thesis are as follows:1. Syntheses of a series of dibenzyltin(IV) chlorides R₂SnCl₂ (R = C₆H₅CH₂,p-FBz,p-ClBz,o-FBz,o-ClBz,m-ClBz,p-CNBz), tribenzyltin(IV) chlorides R₃SnCl (R =C₆H₅CH₂,p-FBz,m-ClBz,o-FBz,o-ClBz,p-CNBz) and bis(trialkyl)tin(IV) oxides (R₃Sn)₂O(R = C₆H₅CH₂,o-ClBz,o-FBz,p-CNBz).2. Preparations of a series of pyruvic acid hydrazone Schiff-base ligandsR-CONH-N=C(CH₃)CO₂H (R = 4-NC₅H₄, C₆H₅, 2-HO-C₆H₄, 4-HO-C₆H₄) andsalicyladehyde hydrazone Schiff-base ligands 2-HO-C6H4-CH=N-NHCO-R(R = 4-NC5H4,4-HO-C6H4).3. Investigations on the reactions of di-or trialkyltin chlorides, dialkyltin oxides andtriphenyltin hydroxide with a ligand pyruvic acid isonicotinyl hydrazone, ten neworganotin(IV) compounds were obtained and characterized by elemental analysis, IR, 1HNMR spectra, and seven of them are also determined by X-ray diffraction. The results showthat weak interactions such as Sn…O are found in the crystals of these organotin(IV)derivatives, which make most of organotin(IV) derivatives dimer. The center tin atoms inthose organotin(IV) compounds are usually rendered seven-coordinated in distortedpentagonal bipyramid geometries, and intermolecular hydrogen bonds create a continuousone-dimensional polymeric chain. The ligand functions as a O, N, O-tridentate chelate andforms a -C=N-N=C-conjugated system, which is introduced into the inner coordinationsphere in the deprotonated enol form. The carboxyl oxygen that dose not bond to the centertin atoms involves the construction of the intramolecular hydrogen bonding. The water helpsto stabilize the whole molecular structure and the construction of both the intra-andintermolecular hydrogen bondings. Besides, spatial resistence from alkyl group of the centertin not only influence the action of the ligand but also influence the molecular polymerization.The former influence is that the greater spatial resistence, organotin(IV) derivatives are morein a transitional tin environment between seven-coordinated pentagonal bipyramidalgeometries and five-coordinated trigonal bipyramid. The sequence ist-butyl>phenyl>benzyl>n-octyl>n-butyl. The latter influence is that the greater the spatialresistence is, the less possible the polymerization is. The sequence ist-butyl>n-octyl>n-butyl>benzyl>phenyl.4. Synthesis and structural characterization of a novel binuclear bridging diphenyltin(IV)compound. The result shows that the compound is a seven-coordinated compound with twoligand coordinated to the center tin atom which contains two different types of tin atom bythe reaction of Schiff base ligand pyruvic acid isonicotinyl hydrazone with diphenyltin oxide.One of the two types is coordinated by tridentate formation of the Schiff base, while the otheris not in the same way due to coordination interaction between two oxygen atoms derivedfrom the carboxyl of the adjacent ligand. Both of the two tin atoms have aseven-coordination geometry in a distorted pentagonal bipyramidal arrangement. Aone-dimensional chain polymeric structure forms through an interaction between the Natoms of pyridine ring and tin atoms of an adjacent molecule.5. Investigations on the reactions of di-and trialkyltin(IV) chlorides with Schiff-baseligands pyruvic acid benzoylhydrazone, 2-hydroxylbenzoylhydrazone,4-hydroxylbenzoylhydrazone, fourteen new organotin(IV) compounds were obtained. Theirspectral properties and molecular structures have been studies carefully with IR, 1H-NMRanalyses and single crystal X-ray diffraction. All data indicate that weak interactions such asSn…O are found in the crystals of these organotin(IV) derivatives, which make most oforganotin(IV) derivatives dimer. The center tin atoms in those organotin(IV) compounds areusually rendered seven-coordinated in distorted pentagonal bipyramid geometries.Particularly, when the reactions of Schiff-base ligands with dialkyltin(IV) chlorides wererecrystallized from ethanol, it forms a seven-coordinated distorted pentagonal bipyramidwith ethanol as coordinated solvent molecules;while the reactions of Schiff-base ligandswith trialkyltin(IV) chlorides were recrystallizecd from methanol, it obtains aseven-coordinated distorted pentagonal bipyramid with methanol as coordinated solventmolecules. The discovery indicates that organotin(IV) compounds with unsaturatedcoordination are apt to further coordinate with solvent containing oxygen atom and the kindof solvent coordination effect may be valuable to the absorption procedure of organotin(IV)antitumour medicine in vivo.6. Synthesis and structural charaterization of an di-n-butyltin(IV) compound withsupramolecular structure. The result shows that the reaction of di-n-butyltin(IV) dichloridewith Schiff-base ligand pyruvic acid 4-hydroxylbenzoylhydrazone in moderate excesssodium ethoxide can produce a special 1D infinite chain self-assembly compound whichcontains a 1, 3-staircase-shaped symmetric tetraorganodistannoxane. The host molecule isdi-n-butyltin(IV) ester and the guest molecule is di-n-butyltin oxide, which derives from thehydrolyze of di-n-butyltin dichloride in excess sodium ethoxide. To identify the reactionmechanism, a reaction was carried out in a little sodium ethoxide. Accordingly, we obtained asimple dialkyltin(IV) ester, in which the phenyl hydroxyl group of Schiff-base ligand doesnot react.7. Investigations on the reactions of bis(trialkyl)tin(IV) oxides (R3Sn)2O with pyruvicacid hydrazone Schiff-base ligands, nine new tetranuclear organotin(IV) compounds wereobtained and characterized by elemental analysis, IR, 1H NMR spectra, three of them are alsodetermined by X-ray single crystal diffraction. All data reveal that these compounds have acommon structural character, namely the compound exhibits a dimeric tetranuclear structurecontaining distannoxane units with two types of tin atoms, in which one tin atom appears tobe seven-coordinated with distorted pentagonal bipyramid geometry, and through a hydroxyloxygen atom linking to the other type of triorganotin nucleus. A possible reaction mechanismhave been given. A trialkyltin(IV) ester is synthesized by condensation reaction ofSchiff-base ligand with (R3Sn)2O after losing R3SnOH, then the enolization of the ligandresults in dealkylation and producing a dialkyltin(IV) ester. Meanwhile, a tetranuclearorganotin(IV) compound is formed when R3SnOH coordinates to the dialkyltin(IV) ester. Inparticular, intermolecular Sn???N weak interactions may be found in the crystals of pyruvicacid isonicotinyl hydrazone derivatives. Thus these molecules show a 2D network structure.8. Studies on the reactions of mono-and dialkyltin(IV) chlorides and salicyladehydehydrazone Schiff-base ligands. Twelve new single-tin dialkyltin(IV) compounds wereobtained. All data from elemental, IR, 1H NMR analyses and single crystal X-ray diffractionreveal that in these compounds the hydroxy oxygen atom and nitrogen atom of C=N bothcoordinate to the tin atom, therefore Schiff-base ligands founcton as tridentate ligands.Dialkyltin(IV) derivatives are all five-coordinated single-tin compounds. In addition, in thecrystals of diphenyl(salicyladehyde 4-hydroxylbenzoyl hydrazone)tin(IV) there exists aethanol which links two adjacent molecules through hydrogen bondings that contribute to thecrystal stability and compactness and result in a hydrogen-bonding bridging dimericarrangement.9. Synthesis and structural characterization of a mono-nuclear zwitterionmonobutyltin(IV) compound. Studies show that the central tin atom displays negative, andthe nitrogen atom of the Schiff base ligand captures the hydrogen ion produced in thereaction, thus make the compound showing uncharged. In the structure of the compound thetin atom is a six-coordinate octahedral configuration including two unsubstituented chlorineatoms occupying axial positions. Meanwhile, the intermolecular hydrogen bondings werefound between one of the chlorine atoms and the adjacent molecular nitrogen atom, whichmake the compound showing 1D infinite chain arrangement.It is worth noting that through these structural characterizations, we found that weakinteraction, hydrogen bonding may benefit the construction of 1D chain or 2D layerstructures of the organotin compounds. And under a certain condition, some structure canrecognize special molecules and proceed self-assemblement to form supramolecules. Thesestructural information may throw new light in the structure-effect relationship of theorganotin(IV) compounds.