Return to search

Synthesis and properties of bidentate coordination compounds of tin

This Thesis describes the synthesis, structural characterization and properties of some tin(II) and tin(IV) compounds containing bidentate ligands. Chapter 1 describes the main spectroscopic techniques used in the identification of tin(II) compounds; infra-red, <sup>119</sup>Sn Mössbauer and n.m.r spectroscopy are outlined, and relevant examples given. A comprehensive listing is given of the main spectroscopic and structural properties of known tin(]3) compounds. Chapter 2 describes the general synthetic methods employed for the formation of tin(II)-oxygen heterocyclic compounds. A range of catecholate and related complexes of tin(II) were synthesized and the role of the substituent investigated with regard to their physical properties, especially their solubilities. The use of 4-nitrocatechol leads to a soluble product, {Sn[O-4-NO<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>O][OC<sub>4</sub>H<sub>8</sub>]}>sub>n</sub>, which enabled it to be studied spectroscopically and its solid state structure to be determined. The nature of the bonding in {Sn[O-4-NO<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>O][OC<sub>4</sub>H<sub>8</sub>]}<sub>n</sub> was investigated using Extended Hiickel molecular orbital calculations. Chapter 3 describes the chemical reactivity of the novel, soluble, tin(II)-oxygen heterocycle {Sn[O-4-NO<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>O][OC<sub>4</sub>H<sub>8</sub>]}<sub>n</sub>. Reaction with iodine gives SnI<sub>2</sub> [O-4-NO<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>O][OC<sub>4</sub>H<sub>8</sub>]<sub>2<sub>. Reaction with the Lewis base such as 1,2-diaminopropane gives Sn[NH<sub>2</sub>CH<sub>2</sub>CH(Me)H<sub>2</sub>N][O-4-NO<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>O][OC<sub>4</sub>H<sub>8</sub>], whilst benzyltriethylammonium chloride gives {[Et<sub>3</sub>BzN][SnCl(O-4-NO<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>O)]}<sub>n</sub>. The solid-state structure of the compound consists of polymeric chains of [SnCl(O-4-NO<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>O)]<sup>-</sup> and associated [Et<sub>3</sub>BzN]<sup>+</sup> cations. Reaction with BF<sub>3</sub>.Et<sub>2</sub>O gives the adduct F<sub>3</sub>B.Sn[O-4-NO<sub>2</sub>- C<sub>6</sub>H<sub>3</sub>O][OC<sub>4</sub>H<sub>8</sub>]. Reaction with W(CO)<sub>5<sub>thf gives {(OC)<sub>3</sub>W.Sn[(O-4-NO<sub>2</sub>- C<sub>6</sub>H<sub>3</sub>O)(OC<sub>4</sub>H<sub>8</sub>)]}<sub>2</sub> in which the tungsten atoms are believed to be bound η<sup>6</sup> to the aromatic rings. Reaction with bis(triphenylphosphine)platinum-ethylene or tris(triphenylphosphine)platinum gives {PtH[PPh<sub>3</sub>]<sub>3</sub>}{[μ<sub>2</sub>-O][μ<sub>2</sub>-OH][Sn(O-4-NO<sub>2</sub>- C<sub>6</sub>H<sub>3</sub>O)]<sub>2</sub>}, the anion containing tin(II) and tin(IV) centres. Reaction with RhCl[CNC<sub>8</sub>H<sub>9</sub>]<sub>3</sub> gives {RhCl[CNC<sub>8</sub>H<sub>9</sub>]<sub>3</sub>[μ<sub>2</sub>-Sn(O-4-NO<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>O)]}<sub>2</sub>. Reaction with Ph<sub>3</sub>PAuCl gives the cluster Au<sub>4</sub>(PPh<sub>3</sub>)<sub>4</sub>(μ<sub>2</sub>-SnCl<sub>3</sub>)<sub>2</sub>, which is the first known example of a compound containing a μ<sub>2</sub>-SnX<sub>3</sub> fragment. In comparison with SnCl<sub>2</sub>, {Sn[O-4-NO<sub>2</sub>- C<sub>6</sub>H<sub>3</sub>O][OC<sub>4</sub>H<sub>8</sub>]}<sub>n</sub> only weakly inserts into the platinum-chlorine bonds of PtCl<sub>2</sub>(dppe). Two molar equivalents of SnCl<sub>2</sub> reacts with PtCl<sub>2</sub>(dppe) to give Pt(dppe)(SnCl<sub>3</sub>)<sub>2</sub>. Addition of a further equivalent of SnCl<sub>2</sub> in the presence of tetraethylammonium chloride gives [Et<sub>4</sub>N][Pt(dppe)(SnCl<sub>3</sub>)<sub>3</sub>]. The platinum centre in this ion has a distorted trigonal bipyramidal geometry. Chapter 4 describes the synthesis of a number of tin(II)-sulphur heterocycles. The reaction between Sn[SC<sub>6</sub>H<sub>4</sub>S] and TMEDA gives a soluble adduct, Sn[SC<sub>6</sub>H<sub>4</sub>S]TMEDA. A number of tin(II)-nitogen heterocycles were also synthesized. Their intense colours and their instability towards air oxidation indicated that they were monomeric in the solid-state. Chapter 5 outlines the basis for non-linear optical properties, especially their SHG effects. A wide range of tris(catecholato)tin(IV) compounds were synthesized and tested for SHG activity. A number were found to have a significant SHG effect, especially [(O-4- NO,sub>2</sub>-C<sub>6</sub>H<sub>3</sub>O)<sub>3</sub>Sn][NHEt<sub>3</sub>]<sub>2</sub>, which has an SHG effect 1.33 x urea.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:291541
Date January 1991
CreatorsStolberg, Tonie Louis
ContributorsMingos, D. M. P.
PublisherUniversity of Oxford
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://ora.ox.ac.uk/objects/uuid:ff861007-1ff0-470e-8554-86749bc291a1

Page generated in 0.0021 seconds