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Title: Dithioimidophosphinates and related systems
Author: Birdsall, David James
ISNI:       0000 0001 3465 1109
Awarding Body: Loughborough University
Current Institution: Loughborough University
Date of Award: 1999
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The condensation reaction of iPr2PCl with hexamethyldisilazane, HN(SiMe3)2, followed by oxidation with sulfur, selenium or hydrogen peroxide yields Pr2P(E)NHP(E'),iPr2, where E = S, Se or 0. Single crystal X-ray experiments give a hydrogen bonded chain in all cases. Analogous PhO, EtO, Et and Ph substituted compounds were synthesised via condensation reactions between R2P(S)NH2 and R'P(S)CI yielding R2P(S)NHP(S)R'2 (R =PhO, Ph; R' = iPr, Et, EtO). Further crystallographic studies revealed iPr2P(S)NHP(S)(OPh)2 and Et2P(S)NHP(S)Ph2 to be hydrogen bonded dimers and iPr2P(S)NHP(S)Ph2 and Et2P(S)NHP(S)(OPh)2 to be hydrogen bonded chains. Reacting these compounds with Zn, Cd, Pd and Pt chlorides led to the formation of tetrahedral and square planar coordination complexes. Crystallographic studies on the complexes of R2P(E)NHP(E')R'2 revealed surprising ME2P2N ring geometries, some adopting pseudo "boat" conformations and others adopting pseudo "chair" conformation. Reactions of R2P(S)NHP(S)R'2 with CuC12 yielded trimeric copper(I) complexes of the type CU3[R2P(S)NP(S)R' 2]3. The trimeric system was found to be fluxional in solution. Crystallographic studies on the complexes show the trimer to have CU3S3 core. Further reactions of R2P(S)NHP(S)R' 2 with various tellurium (H) and (IV) salts yielded complexes of the types Te[R2P(S)NP(S)R' 2]2 and Te[R2P(S)NP(S)R' 2]Cl2,C6H4.0CH3. Crystallographic studies on the complexes show the tellurium to adopt pseudo two coordinate, four coordinate (square planar) and five coordinate (square based pyramid) arrangements. Tetradentate ligands of the type R2P(S)NHP(S)Ph(CH2)3P(S)PhNHP(S)R2 (where R = Ph or OPh) were synthesised by the condensation of NH2P(S)Ph(CH2)3P(S)PhNH2 with R2P(S)CI. Preliminary coordination studies suggest the formation of ML complexes were M = Zn, Cd and Ni. Molecular modelling techniques were used to investigate the optimum size of the "spacer groups" which links the two dithioimidophosphinate ligands. Using MNDOd and DFT optimisations, and with comparison to unlinked examples, the size of the ideal group was determined with respect to each particular metal.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Condensation reactions; Ligands; Crystallography