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Durham e-Theses
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Synthetic and spectroscopic studies of some new organophosphorus (111) and (v) compounds

Ali, Rusmidah (1987) Synthetic and spectroscopic studies of some new organophosphorus (111) and (v) compounds. Doctoral thesis, Durham University.



The acceptor properties of some halogenated organophosphorus (V) compounds towards chloride, pyridine, 2,2'-bipyridine and 1,10-phenanthroline have been investigated by means of (^31)P n.m.r. spectroscopy. It was found that C(_6)F(_5)PCl(_4) forms a six-coordinate anionic species C(_6)F(_5)PCl(_5)(^-) with R(_4)NCl which dissociates in solution. CCl(_3)PCl(_4) also show acceptor properties towards R(_4)NCl, but a stable adduct was only formed with Pr(_4)NCl in PhN0(_2), where no dissociation was observed. In CH(_2)CI(_2), decomposition occurred in which CCI(_3)PCI(_2) was detected. In contrast, C(_2)C1(_5)PC1(_4) only showed temporary formation of the adduct with Et(_4)NCl in CH(_2)CI(_2), followed by decomposition, but it did not do so with R(_4)NCl (R=n-Pr, n-Bu or n-Pe) either in CH(_2)Cl(_2) or PhN0(_2), where only decomposition products were observed. As expected, the higher members of the series R(_2)PCl(_2) (R=C(_6)F(_5) or CCl(_3_)) and (C(_6)F(_5))(_3)PCl(_2) did not form adducts with R(_4)NCl, either in CH(_2)CI(_2) or PhN0(_2). RPCl(_4) (R=C(_6)F(_5) or CCl(_3)) react with pyridine to give RPCl(_4).py, but no adduct was found with bidentate ligands (L). In contrast, the complexes [C(_2)Cl(_5)PCl(_3)L](^+)Cl(^-) were isolated. RPCl(_3)(^+)x(^-) (R=C(_6)F(_5) and CCl(_3)(_i) X=SbCl(_6) and BCl(_4)) also form adducts with L, giving six-coordinate cationic species [RPCl(_3)L](^+)X(^-) which exist in two isomeric forms in solution but only one isomer is dominant when the solid is isolated. The ionic compound [C(_6)F(_5)PBr_3)][BBr(_4)] was isolated, but attempts to establish the chemical shift for the six-coordinate species with bidentate ligands L failed.Organophosphorus (111) halides (C(_6)F(_5))(_n)PC1(_3-n)(X=C1, Br, n=l, 2) and pseudohalides (C(_6)F(_5) (_n)PX(_3-n) (X=NCS, n=l; X=CN, n=2) show acceptor properties towards Y(^-) (Y=C1, Br, I and NCS) to form four-coordinate phosphoranides [(C(_6)F(_5))(_n)PX(_3-n)Y](^-), which all proved to be very unstable. Substitution reactions occurred with CN(^-) or NCS(^-) for (C_6)F(_5))(_N)PX(_3-n) (X=C1, Br) and with CN(^-) for C(_6)F(_5)P(NCS)(_2). No acceptor properties were observed towards Cl(^-), Br(^-), I(^-), CN(^-)or NCS(^-) ions for CCI(_3)PC1(_2) and (C(_6)F(_5))(_2)PNCS, whereas the compounds RP(NCS)(_2), (R=Me, Et or Ph) are thermally unstable and their Lewis acid behaviour could not be investigated. Substitution reactions occurred between AgNCS and RPC1(_3)(^+)X(^-) (R=Me or Ph, X=SbCl(_6); R=C(_6)F(_5), X=SbC1(_6) or BC1(-4)), giving [ RPCl(_3-n) (NCS )(_n)](^+) (l<n<3), but with AgCN only MePCl(_3-n)(CN)(_n)(^+) (2<n<3)) were detected in solution. Reaction of C(_6)F(_5)PCl(_3)(^+)x(^) (X=SbCl(_6) or BCl(_4)) with LiN(_3) gave [C(_6)F(_5)PCl(_3-n) (N(_3)(_n)](^+)X(^-) which were detected in solution only. In the C(_6)F(_5)PCl(_3)BCl(_4)/NCS(^-), CN(^-) and N(_3)(^-) systems, substitution also occurred at the BCl(_4)(^-) anion, and the BCl (_4-n) Y (_n)(^-) species were detected in solution by means of (^11)B n.m.r.-) Decomposition occurred on addition of M(^+) NCS(^-) (M=Ag,Li or Et(_4)N) to RPCl(_4)( or RPC1(_5)(^-) (R=Me, Ph or Et) solutions to give RPC1(_2), RPSC1(_2) and RPS(NCS)(_2), while substitution occurred with [C(_6)F(_5)PCl(_5)](^-) giving [C(_6)F(_5)PCl(_5-n(NCS)(_n)](^-) (n = 1 and 2), followed by decomposition to C(_6)F(_5)PC1(_2), C(_6)F(_5)P- (NCS)(_2), C(_6)F(_5)PS(NCS)(_2) and C(_6)F(_5)PS(CN)(_2). Conversely, the cyano-derivatives RPC1(_5-n)(CN)(_n)(^-) (R=Et, l<n<5; R=C(_6)F(_5), 1<n<4 and R=CC1(_3), 1<n<3) were detected in solution and the complexes [Pr(_4)N][EtP(CN)(_5)], [R(_4)N][C(_6)F(_5)PCl(CN)(_4)] (R=Et or Pr) and [Pr(_4)N][CCl(_3)PCl(_5-n)(CN)(_n)] (n=2 and 3) were isolated .

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:1987
Copyright:Copyright of this thesis is held by the author
Deposited On:08 Feb 2013 13:44

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