No description available.

The decomposition of three phenyl-substituted 1,2-dithiolium salts, 3,5-diphenyl-, 3-phenyl- and 4-phenyl- in aqueous, ethanol and DMSO solutions have been examined. With bases of the type hydroxide, ethoxide, DMSO, and acetate, the 1,2-dithiolium ion formed adducts reversibly. Orders of adduct stability were determined in ethanol and water. Many of the adducts were unstable and decomposed to monothio-(beta)-dicarbonyls. The monothio-(beta)-dicarbonyls were in turn unstable and decomposed in aqueous media to the corresponding-(beta)-diketone in the case of the monothiodibenzoylmethane. / Reaction of the 1,2-dithiolium ions with sodium sulphide or sodium borohydride led to dithio-(beta)-dicarbonyls. These species were unstable and decomposed to monothio-(beta)-dicarbonyls in the presence of water. It was possible to observe the formation of metal chelates of monothio- and dithio-(beta)-dicarbonyls in DMSO for several systems. Metal ion and ligand stability orders were established. / Chelates of dithio-(beta)-dicarbonyls decomposed to monothio-(beta)-dicarbonyls in the presence of trace amounts of water. Monothio-(beta)-dicarbonyl chelates were also sensitive to water with dibenzoylmethane produced from monothiodibenzoylmethane chelate decomposition. / Mechanisms for 1,2-dithiolium ion decomposition in the presence and absence of metal ions have been proposed.

Diastereomers of CpRh{C(O)Me}(P*)I, (P* (TBOND) (S)-Ph(,2)PNHCH(Me)Ph), have been prepared and separated. Decarbonylation with AgBF(,4) gave a single diastereomer of CpRhMe(CO)(P*)(.)BF(,4) and subsequent treatment of the salt with anions likewise gave single isomers of CpRh{C(O)Me}(P*)X (X = Cl, Br, I, SCN, NCS). The high stereospecificity of these transformations is attributed to the ability of the acyl ligand to undergo stereospecific reversible decarbonylation such that the methyl group occupies the site vacated by the iodide ligand, i.e., inversion. Addition of N(,3)('-) and MeO('-) to the salt resulted in the stereospecific formation of CpRhMe(P*)X' (X' = NCO, COOMe). Metathesis of CpRh{C(O)Me}(P*)Cl with I('-) proceeded with retention of configuration at rhodium. / The chiral complexes (1-C(,9)H(,6)Cl)Rh(COD), (COD (TBOND) 1,5-cyclooctadiene), and (1-C(,9)H(,6)X)Mn(CO)(,3), (X = Cl, Br, I) have been synthesized via diazoindene insertion. Only the pentahapto bonding mode has been detected for these complexes. / Photochemical and chemical decarbonylation of trans-CpFe(CO)(,2){C(O)CH=CHR}, (R = Ph, Me), proceeded with retention of geometry about the double bond to give trans-CpFe(CO)(,2){CH=CHR}.

The complexes L(,2)Pt(SR)(,2), where L = PPh(,3), PMePh(,2), PMe(,2)Ph, were prepared in high purity and yield by treating the dichlorides with thiols and triethylamine under nitrogen atmosphere. Their geometry is cis for R = ('n)Pr, ('i)Pr, CH(,2)Ph and trans for R = 4-C(,6)H(,4)Me. Reactions of cis-L(,2)PtCl(,2) and H(,2)S/K(,2)CO(,3) or NaSH in the presence of dichloromethane afforded the complexes L(,2)Pt(S(,2)CH(,2)), containing the novel bidentate methanedithiolato ligand. The thiolato-bridged dimers {LPt(SR')(,2)}(,2), where R' = CH(,2)Ph, 4-C(,6)H(,4)Me, were isolated by fusion of the appropriate monomers in vacuo. The compound {(PMePh(,2))Pt(SCH(,2)Ph)((mu)-SCH(,2)Ph)}(,2) has the cis-symmetrical structure. Treatment of the complexes cis-L(,2)Pt(SCH(,2)Ph)(,2) with phtNSSNpht, where H-Npht = phthalimide, led to stepwise displacement of the phenylmethanethiolato ligands by phthalimido groups. / The first platinadisulfanes, complexes of the type cis-(PPh(,3))(,2)Pt(Npht)(SSR''), where R'' = ('n)Pr, ('i)Pr, CH(,2)Ph, 4-C(,6)H(,4)Me and Npht, were synthesized in good yield by the oxidative addition of R''SSNpht to (PPh(,3))(,2)Pt(C(,2)H(,4)). Similarly, addition of R''SNpht gave cis-(PPh(,3))(,2)Pt(Npht)(SR'').

No description available.

New phosphine ligands which also contained crown ether groups were synthesized by condensing two main reagents. Reagent A was Ph2P(CH2)3NH2 and it was prepared by reductingPh2P(CH2)2CN with LiALH4 in diethyl ether. Ph2P(CH2)2CN is obtained by reacting Ph2PH and CH2=C(H)CN in a Michael-type reaction. Reagent B, 4-formyl-benzo-15-crown-5, was obtained from the reaction of 3,4 dihydroxybenzaldehyde with 1,11 dichloro-3,6,9 trioxoundecane.By condensing the benzaldehyde crown ether and the phosphine amine, a Schiff-base type crown ether containing both P(III) and N(III) centers was obtained. Spectroscopic studies of the ligand and its Pd(II) derivative have shown PdCl2[Ph2P.(CH2)3N CH-C6H3(OMe)2]2 were characterized by that metal binding occurred exclusively on the P( III) center.A model ligand was synthesized by condensing 3,4-dimethoxybenzaldehyde with Ph2P(CH2)3NH2 to obtain an analogous product. Both ligands, Ph2P(CH2)3N=CH-benzo-15crown-5 and Ph2P(CH2)3N=CH -C6H3(OMe)2 and their palladium derivatives, PdCl2[Ph2P(CH2)3N=CH-benzo-15-crown-5]2 and spectroscopic and elemental analysis. The Pd(II) derivatives were synthesized from the reactions of (Ph2CN)2)PdC12 with the ligands. / Department of Chemistry

The success of homogeneous asymmetric catalysis has been attributed to the structure and stereochemistry of the coordinated ligand(s). The most effective ligands are C₂-symmetrical bisphosphines containing either a rigid chiral backbone linking two PPh₂ units or a bisphosphine, DIPAMP containing two chiral phosphine units linked by an achiral backbone. The synthesis of P-chiral ligands of this type has been severely hindered by the lack of a general synthetic route allowing the incorporation of phosphorus chirality without the need for separation of diastereomeric precursors or resolution of intermediate enantiomers. The objective of this work was to develop a general synthetic route to homochiral bulky arylphosphines with substantial flexibility in the groups at phosphorus and extend the approach to new P-chiral bisphosphines. In one approach, diastereomerically pure (2R, 4S, 5R)-2,5-diphenyl-3,4-dimethyl-1,3,2-oxazaphospholidine was prepared directly from PhPCl₂ using l-ephedrine as a chiral auxiliary. Stereospecific oxidation using Bu^tOOH gave the corresponding P-oxide which was shown to have R-stereochemistry at phosphorus by single-crystal X-ray diffraction studies. The compound reacted regiospecifically with ortho-anisylmagnesium bromide to afford the product formed by P-O bond cleavage with >96% d.e. and with retention of configuration at phosphorus as demonstrated by single-crystal X-ray diffraction studies. The l-ephedrine residue was replaced by O-methyl under acid-catalysis with inversion of configuration and with >95% e.e., the reaction was monitored by ¹H n.m.r. spectroscopy which gave t_1/2 of ca. 30 min. Attempts to incorporate para-fluorophenol using similar conditions led to the isolation of the pyrophosphinate in low yield. The OMe residue in the methyl (ortho-anisyl)phenylphosphinate was readily displaced by aliphatic Grignard reagents giving the corresponding phosphine oxides with inversion of configuration and with >95% e.e. Displacement of methoxy using aryl magnesium bromides showed similar enantioselectivity but in lower chemical yield, however the corresponding arylmagnesium chlorides were more efficient. In a second approach, diastereomerically pure (2R, 4S, 5R)-2-chloro-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidine was prepared from PCl₃ and l-ephedrine. The compound underwent diastereoselective P-C1 cleavage with aryl Grignard and aryllithium reagents with net retention of configuration at phosphorus and with 90% d.e. Oxidation of the ortho-anisyl derivative afforded (2R, 4S, 5R)-2-(ortho-anisyl)-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidine-2-oxide which was subsequently reacted with a range of bulky aryl Grignard reagents to afford the corresponding biarylphosphinamides with retention of configuration at phosphorus. Subsequent acid-catalysed methanolysis and displacement of the methoxy residue with PhMgCl afforded a range of bulky arylphosphine oxides with defined configuration at phosphorus with >95% e.e. as determined by ¹H n.m.r. methods. (S)-ortho-anisyl (meta-anisyl)phenylphosphine oxide underwent regiospecific ortho-lithiation on the meta-anisyl ring which on quenching with D₂O afforded the corresponding 2-deuteride in 80% yield. The 2-iodo analogue was also prepared although in low chemical purity and is a key precursor to new axially dissymmetric bisphosphines containing chiral phosphorus centres. Other approaches to P-chiral ferrocenyl ligands and biaryl ligands are also described and modifications for further development are implicated. An X-ray crystallographic study of six aryl-oxazaphospholidines is also presented and demonstrates the influence of the substituents at phosphorus in determining the conformation of the 1,3,2-oxazaphospholidine ring. A comparison with solution ¹H n.m.r. data showed, in some cases, good correlation between the P-O-C-H dihedral angle and the corresponding solid state torsion angle.

No description available.

Organic light emitting diodes (OLEDs) are an emerging display technology with the advantages of being efficient, bright, portable and flexible. In this work, a number of novel compounds have been developed for incorporation into OLEDs as emitting dopants. A series of ligands containing dipyrido[3,2-a:2�,3�-c]phenazine substituted at the 11-position with ethyl ester, bromo-, nitrile and 5-phenyl-1,3,4-oxadiazole moieties have been synthesised. Each of the ligands were coordinated to Re(I), Cu(I), Ru(II) and Ir(III) metal centres. Ligands and complexes were characterised by �H NMR and IR spectroscopy, mass spectrometry and microanalysis. Single crystal X-ray analyses were performed on fac-chlorotricarbonyl(dipyrido[3,2-a:2�,3�-c]phenazine-11-carboxylic ethyl ester)rhenium (triclinic, P-1, a = 6.403(5) Å, b = 10.388(5) Å, c = 16.976(5) Å, α = 84.087(5)�, β = 84.161(5)�, γ = 79.369(5)�, Z = 2, R1 = 0.0536, wR2 = 0.0978), fac-chlorotricarbonyl(11-bromodipyrido[3,2-a:2�,3�-c]phenazine)rhenium.CH₃OH (monoclinic, C2/c, a = 19.506(5) Å, b = 18.043(5) Å, c = 13.320(5) Å, α = γ = 90�, β = 114.936(5)�, Z = 4, R1 = 0.0345, wR2 = 0.0827), fac-chlorotricarbonyl(11-cyanodipyrido[3,2-a:2�,3�-c]phenazine)rhenium (triclinic, P-1, a = 6.509(5) Å, b = 12.403(5) Å, c = 13.907(5) Å, α = 96.88(5)�, β = 92.41(5)�, γ = 92.13(5)�, Z = 2, R1 = 0.0329, wR2 = 0.0701), bis-2,2�-bipyridyl(2-(11-dipyrido[3,2-a:2�,3�-c]phenazine)-5-phenyl-1,3,4-oxadiazole)ruthenium triflate.2CH₃CN (triclinic, P-1, a = 10.601(5) Å, b = 12.420(5) Å, c = 20.066(5) Å, α = 92.846(5)�, β = 96.493(5)�, γ = 103.720(5)�, Z = 2, R1 = 0.0650, wR2 = 0.1458) and bis-(2-phenylpyridine-C�,N�)(dipyrido[3,2-a:2�,3�-c]phenazine)iridium(III) hexafluorophosphate.(CH₃)₂CO (triclinic, P-1, a = 13.505(5) Å, b = 16.193(5) Å, c = 19.788(5) Å, α = 92.857(5)�, β = 98.710(5)�, γ = 93.432(5)�, Z = 2, R1 = 0.0494, wR2 = 0.1097). The ground and excited state properties of the ligands and complexes were investigated by a range of techniques, including electrochemistry, absorption and emission spectroscopy, spectroelectrochemistry and excited state lifetime studies. Complexes of dppz-based ligands typically show MOs which are segregated over either the bpy or phz region of the dppz backbone. The properties of the Ru(II) and Ir(III) complexes of the ligand series investigated in this work were consistent with this model, and the LUMOs of these complexes were assigned as the b₁(phz) phz-localised MO. The Re(I) and Cu(I) complexes of the ligand series appeared to show MOs which were delocalised over the entire dppz ligand. A modular complex containing an electron transport group, hole transport group and emitting centre was synthesised. The complex fac-tricarbonyl(trans-(E)-1-((2,2�:5�,2��-terthiophen)-3�-yl)-2-(4�-pyridyl)-ethane)(2-(11-dipyrido[3,2-a:2�,3�-c]phenazine)-5-phenyl-1,3,4-oxadiazole)rhenium(I) hexafluorophosphate was oxidised and reduced readily, encouraging efficient transport of both holes and electrons. However, this resulted in the complex having a small band gap and hence a low quantum yield of emission. Emission from this complex appeared to be from more than one state. The complexes containing the dppz-based ligand series show complicated excited state behaviour. Emission behaviour is consistent with input from more than one state for many of the Re(I), Cu(I) and Ir(III) complexes. The Ru(II) complexes of the ligand series emit from a �MLCT state between metal-based and bpy-based MOs located on the dppz ligands, as is usual for complexes of this type. All complexes containing 11-cyanodipyrido[3,2-a:2�,3�-c]phenazine showed extremely short excited state lifetimes consistent with extremely efficient non-radiative deactivation of the excited state. Ligands and complexes were incorporated into OLEDs with the structure [ITO/PEDOT:PSS/PVK:BuPBD:dopant/BCP/Alq₃/LiF/Al] to test their ability to behave as emissive dyes. Many of the compounds behaved poorly as dopants due to their low emission quantum yields, and poor alignment of HOMO and LUMO energy levels with those of the other compounds within the device. �MLCT-based emission was achieved through energy transfer from the PVK host for the devices containing chlorotricarbonylrhenium(I) complexes of the ligand series. The OLEDs containing Ru(II) and Ir(III) complexes also emitted from dopant-centred �MLCT states. In these devices, dopant excitation appeared to occur through direct charge trapping from the adjacent hole transport and electron transport layers.

Errata inserted in preliminary pages. / Bibliography: leaves 171-184. / 184 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis details the synthesis, characterization and reactions of some transition metal complexes containing ligands derivived from the diacetylenes 1,4-bis (trimethylsilyl)buta-1,3-diyne and buta-1,3-diyne. Some related chemistry of the unsaturated carbone complexes are also explored. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1997