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.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:291541 |
| Date | January 1991 |
| Creators | Stolberg, Tonie Louis |
| Contributors | Mingos, D. M. P. |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:ff861007-1ff0-470e-8554-86749bc291a1 |
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