Synthesis, Characterization And Application Of Novel Organoantimony And Organobismuth Complexes

In recent years, hypervalent organoantimony and organobismuth compounds bearing intramolecular Eâ†'M (E=N,O, S; M=Sb, Bi) coordinations have attracted much attention due to their intriguing chemistry, structures and applications in areas such as medicine, catalysis, and organic synthesis. The most of these compounds contain bidentate or tridentate aryl ligands with one or two pendant coordinating groups, i.e. so-called C,E or E,C,E and C,E,C-chelating ligands (E=N, O, S). The coordination of the ligands with the antimony or bismuth center through the carbon atom of the aryl group as well as through the N, O, S atom of the pendant arm would result in high stability. In contrast to compounds containing bidentate C,N-chelating ligands, related species bearing bidentate C,E-chelating ligands (E=O, S) were somewhat less investigated. So far there is no organoantimony and organobismuth complexes with asymmetric C,E,C-chelating (E=N,O, S) ligands that have been reported.9bidentate or tridentate organic ligands bearing O or S atoms as coordination atoms and13new air-stable organoantimony and organobismuth compouds containing intramolecular Eâ†'M (E=N, O, S; M=Sb, Bi) coordinations were synthesized in this thesis. The structure and properties of these compounds were characterized by element analysis, NMR, X-Ray single crystal diffraction and TG-DSC techniques. Moreover, they were examined in the ring opening of epoxides with aromatic amines and allylation of aldehyde or imines with allylating reagents. The results are shown as follows.(1) Synthesis of ligand precursors:9ligand precursors bearing0or S coordinating atoms, i.e.5bidentate C,E-chelating ligands (E=O, S),2symmetric and2asymmetric tridentate C,E,C-chelating ligand precursors (E=O, S) were synthesized in high yield by Williamson Synthesis, viz. nucleophilic substitution of alkyl halide with sodium alkoxide or mercaptan sodium under anhydrous conditions.(2) Four organoantimony chlorides [E(CH2C6H4)2SbCl,(C6H4CH2ECH2C10H6)-SbCl (E=O, S)] and five organobismuth chlorides [O(C6H4CH2)2BiCl,(C6H4CH2ECH2C10H6)BiCl and [2-(MeECH2)C6H4]2BiCl (E=O, S)] were synthesized from the bidentate or tridentate ligand precursors [(2-BrC6H4CH2)2E,1-Br-2-[(2’-BrC6H4CH2E)CH2]C10H6and1-Br-2-(MeECH2)C6H4(E=O, S)]. Single crystal X-ray diffraction analysis results reveal that the metal centre (Sb, Bi) is strongly coordinated with the donor O or S atom of tridentate C,E,C-chelating ligands and bidentate C,E-chelating ligands (E=O, S). In organoantimony and organobismuth chlorides with asymmetric tridentate C,E,C-chelating ligands and bidentate C,E-chelating ligands (E=O, S), the intramolecular Eâ†'Sb or Eâ†'Bi interaction results in "chelate induced-M-chiral"(M=Sb, Bi) compounds.(3) An air-stable organobismuth triflate complex containing a novel5,6,7,12-tetrahydrodibenzo[c,f][1,5]oxabismocine framework was synthesized by the reaction of organobismuth chloride ((C6H4CH2)2BiCl with AgOSO2CF3, and characterized by NMR, single-crystal X-ray diffraction and TG-DSC techniques. The organobismuth framework is cationic, and the complex shows relatively strong Lewis acidity (0.8<Ho≤3.3). It exhibits high catalytic activity towards the ring-opening reaction of epoxides in aqueous media with aromatic amines at room temperature. This catalyst also shows good stability, recyclability and reusability. The catalytic system affords a simple and efficient method for the synthesis of P-amino alcohols.(4) Two air-stable organobismuth triflate complex, i.e.[2-(MeOCH2)C6H4]2Bi-OSO2CF3and{[2-(MeSCH2)C6H4]2Bi}+[OSO2CF3]-were synthesized by the reaction of organobismuth chloride [2-(MeECH2)C6H4]2BiCl (E=O, S) with AgOSO2CF3, and characterized by NMR, single-crystal X-ray diffraction and TG-DSC techniques. Single crystal X-ray diffraction analysis reveal that the latter is cationic, and the complex shows Lewis acidity strength of4.8<Ho<6.8. The acidity of compound [2-(MeOCH2)C6H4]2BiOSO2CF3is3.3<Ho<4.8. The two organobismuth triflate and their precursors chlorides exhibit good catalytic efficiency and reusability for the allylation reaction of different aldehydes with tetraallyltin in methanol, giving the corresponding homoallylic alcohols in excellent yields.(5) An air-stable organoantimony triflate complex containing intramolecular Nâ†'Sb interaction was synthesized by the reaction of organoantimony chloride PhN(CH2C6H4)2SbCl with AgOSO2CF3, and characterized by NMR, single-crystal X-ray diffraction and TG-DSC techniques. The complex shows relatively strong Lewis acidity (0.8<Ho<3.3). It exhibits good catalytic efficiency towards the allylation reaction of imines in dichloromethane with allytributyltin at room temperature. Furthermore, This catalyst shows good stability, recyclability and reusability, and is almost independent of the reactant substrates. The catalytic system affords a new and efficient method for the synthesis of homoallylic amines.