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    Iminophosphine ligands and their metal binding properties : a thesis presented in partial fulfilment of the requirements for the degree of Science in Chemistry at Massey University, Palmerston North, New Zealand
    (Massey University, 2003) McBeth, Kurt Allen
    This work focuses on the complexes of two iminophosphine ligands, N-(2-diphenylphosphinobenzylidine)-aniline (NP) and N-(2-diphenylphosphinobenzylidine)-4'-(benzo-15-crown-5) (O₅NP), and their complexes with Cu(I), Ag(I), Au(I), Cr(0), Mo(0) and W(0). The cation binding properties of the complexes of O₅NP have been investigated. Chapter One describes the aims of this work and also provides a brief introduction to ligands containing phosphorus and nitrogen donor atoms as well as crown ethers and their inclusion in transition metal complexes. The analytical technique of electrospray mass spectroscopy (ESMS) is introduced and its use in the study of cation binding to crown ethers and cryptands discussed. Chapter Two looks at the Cu(I), Ag(I) and Au(I) complexes of NP and O₅NP, such as [M(L)₂][PF₆] (M = Cu, Ag, Au; L = NP, O₅NP), [M(NP)X]₂, [M(O₅NP)Cl]₂ (M = Cu, Ag), Au(NP)X and Au(O₅NP)Cl (X = Cl, Br, I). Reported in this chapter are the X-ray structural analyses of O₅NP, [Cu(NP)₂][PF₆], [Ag(NP)₂][PF₆], [Au(NP)₂][PF₆], [Cu(NP)Br]2, Au(NP)Cl and Au(NP)Br. Far and Near IR, ¹H and ³¹P NMR and ESMS were used to investigate the nature of the complexes. The [M(L)₂][PF₆] complexes displayed a clear trend in which the number of coordinated imines decreased as the soft nature of the metal centre increased. Both the Far IR and crystal structure analyses showed the Cu(I) and Ag(I) halo complexes to be dimeric with bridging halides and the Au(I) halo complexes to be monomeric with terminal halides. The ³¹P NMR signal was found to be dependent on the mass of the metal centre. In Chapter Three the Cr(0), Mo(0) and W(0) carbonyl complexes of NP and O₅NP are discussed. To characterise the complexes, IR, ESMS and ¹H, ³¹P and ¹³C NMR techniques were employed. X-ray structural analyses of Mo(CO)₄(NP) and Mo(CO)₄(O₅NP) were also used. It was found that the metal centres had an octahedral geometry with the ligands being bidentate via the P and N atoms and having a cis conformation. Upon coordination, the ¹H NMR signal of the imine proton moves to lower frequencies, whereas the ³¹P NMR signal moves to higher frequencies. It was also demonstrated that the presence of the crown ether has no significant effect on the structure of the metal centre. Cation binding to the complexes of O₅NP, the free ligand, and starting material, 4'-aminobenzo-15-crown-5 (O₅NH₂), is discussed in Chapter Four. Electrospray mass spectroscopy (ESMS) was used as a qualitative measure of the relative cation binding strengths. The X-ray structural analyses of the inclusion complexes W(CO)₄(O₅NP)Na(PF₆) and [Cu(O₅NP)₂]K.[PF₆]₂ were determined, and provided information on the coordination of alkali cations by these complexes. W(CO)₄(O₅NP) binds Na⁺ within the cavity of the benzo-15-crown-5 moiety which experiences significant change to its conformation. [Cu(O₅NP)₂][PF₆] binds K⁺ in a sandwich formation suggesting that rotation of the ligands occurs about the Cu(I) centre. The starting material, O₅NH₂, and free ligand, O₅NP, were selective towards K⁺, forming a 1:1 species. The complexes M(CO)₄(O₅NP) (M = Cr, Mo, W) and [M(O₅NP)₂][PF₆] (M = Cu, Ag, Au) were selective towards Na⁺ and K⁺ respectively with a 1:1 formation. The halide complexes, [Cu(O₅NP)Cl]₂, [Ag(O₅NP)Cl]₂ and Au(O₅NP)C1, displayed different selectivities from each other. Both [Cu(O₅NP)C1]₂ and [Ag(O₅NP)Cl]₂ dissociated in solution to give the monomers which selectively bound Li⁺ and K⁺ respectively in a 1:1 species. The Au(O₅NP)Cl complex was selective towards Na⁺.
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    An investigation of Ru(II) complexes containing sterically demanding imido ligands : a thesis presented to Massey University in partial fulfilment of the requirements for the degree of Master of Science
    (Massey University, 1995) Steedman, Andrew John
    Monomeric, low oxidation state, ruthenium imido compounds, (η6 -arene) RuN-Ar' (arene= p-cymene and C6 Me6 ; Ar'= 2,4,6-tri-tert-butylphenyl) have been synthesized from [(η6 -arene) RuCl2 ]2 and 4 equiv of LiNHAr' in THF. An X-ray crystal structure of (η6 -p-cymene) Ru=NAr' showed a short Ru-N distance (1.753(3)Ǻ) and a near linear Ru-N-C angle (177.8(4)° ) consistent with ruthenium to nitrogen multiple bonding. Reaction of [(η6 -p- cymene) RuCl2 ]2 with 4 equiv of LiNHR (R= 2,6-dimethylphenyl or 2,6-diisopropylphenyl) in THF afforded the dimeric ruthenium imido compounds [(η6 -p-cymene) Ru(µ-NR)]2. An X-ray crystal structure of [(η6 -p-cymene) Ru(µ-NAr)]2 (Ar= 2,6-diisopropylphenyl) showed an averaged Ru-N distance of 1.974(8)Ǻ and features characteristic of Ru(II) bridging imido complexes. Addition of 2 equiv of LiNHAr to [(η6 -C6 Me6 ) RuCl2 ]2 gave a HCl adduct, (η6 -C6 Me6 ) RuClNHAr, characterisation of the complex was obtained by X-ray diffraction. Reaction of the HC1 adduct with phenylisocyanate gave the ureylene metallacycle, (η6 -C6 Me6 ) RuN(Ar)C(0)N(Ph), indicating the presence of an imido intermediate. This complex was shown to have a υ(CO) band at 1596cm -1 and is comparable with other monomeric ureylene complexes. In addition, the complex [(η6 -p-cymene) Ru(µ-NAr)]2 was made from 2 equiv of the amine, ArNH2 , and [(η6 -p-cymene) RuCl2 ]2 and dehydrochlorinated with KN(SiMe3 )2 providing an alternative route. Further, an X-ray crystal structure of the amine complex, (η6 -p-cymene) RuCl2 (ArNH2 ) was obtained. The reaction of (bpy)2 RuCl2 (bpy= 2,2'-bipyridine) with LiNHAr' in THF afforded the complex, (bpy)2 Ru=NAr', characterised by nmr and elemental analysis.
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    Synthesis and physical properties of hetero-substituted-HATNs and their Cu(I) and Re(I) complexes : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry at Massey University, Palmerston North
    (Massey University, 2013) Parker, Nyree Dawn
    The electron deficient hexaazatrinaphthalene compounds are of interest for photovoltaic (PV) and molecular devices. These molecules contain multi phenazine (a common dye chromophore) centres that allow coordination of metals, forming complexes that have been shown to have photophysical properties that could be commercially valuable. HATNAs have been investigated for use in molecular devices; including liquid crystals (LCs), light emitting diodes (LEDs), PVs, and field effect transistors (FETs) by a variety of groups. The initial goal of this thesis was the synthesis of mixed or ‘hetero’-HATNs. Preliminary investigations leading into the synthesis of HATNAs showed a number of problems associated with solubility, purification, and stability of these compounds, however a method was established and six hetero-HATNs, HATN-4Me, HATN-4Br, HATN-2Me, HATN4Br2Me HATN-2Br and HATN-4Me2Br, were synthesised and carried throughout the thesis. The rhodizonic acid route and its reactions with the appropriate diaminobenzenes followed by oxidation with nitric acid and then further reactions with diaminobenzene was considered the best. The crystal structure of one of the possible intermediates for HATN production, PTK-2Me which is based on a 1,2,3,4-phenazinetetrone displays the presence of a gem-diol equilibrium on one of the rings which is no longer aromatic. The crystal structure of PKH-2Me (PKH = 2,3-dihydroxyphenzine-1,4-dione) which is a precursor to the PTK-2Me intermediate shows the C-OH bonds are shortened due to the partial double bond character due to a shifting of the equilibrium between a ketone and a hydroxyl group. The crystal structure of HATN-4Me shows all of the aromatic rings to be mostly planar with slight distortion. The MALDI mass spectra for each of the electron deficient HATNs displays a band due to [M+2]+ cations which is unusual and possibly formed by a [M+2H++e-] species. Physical properties of the six HATNs were investigated using UV/Vis, Raman and IR spectroscopies. They were tested as the electron-transport-material in a field effect transistor. It was found that HATN-4Br had the highest electron mobility of 8.13 x 104 cm2V-1s-1 and this was obtained after vacuum deposition onto a substrate rather than a solution processed deposition. However as it has a high resistance it is not suitable for a FET device. The HATNs all display first reduction potentials at -0.9 V with a second at about -1.4 V. They are all quite close and do not appear to follow the expected trend according to the nature of the functional groups. The HATNs coordinate to rhenium to form A and S isomers which are difficult to isolate. The HATN-1Re complexes display similar physical properties. When two rhenium atoms are added (HATN-2Re) there is a noticeable red-shift in their absorption spectra (100 nm). Crystal structures of HATN-4Me-1ReA and HATN-4Me-1ReS and HATN-2Me-2ReS were obtained and these show twisting of the HATN core up to 13°. These structures showed the p-p stacking ability of the HATN complexes ranging from 1 to 3 ring overlaps as well as solvent interactions. Copper willingly binds to all three bidentate hetero-HATN sites and has the unusual property of a colour change between the solvents acetonitrile and chloroform. The reason for this colour change is discussed and found possibly to be due to copper dissociation.
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    Synthesis, structure and reactivity of the later transition metal complexes containing a multidentate phosphorus-nitrogen hybrid ligand : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry at Massey University
    (Massey University, 2000) Kennedy, Steven Michael Fornara
    Chapter 1 - This first part of the chapter aims to give the reader a flavour of the chemistry concerning phosphorus-nitrogen hybrid ligands containing both phosphorus and nitrogen donor atoms. This will be achieved by highlighting selected relevant examples from the literature. The second part will introduce the ligand 2-(diphenylphosphino)-N-[2-(diphenylphoshino)benzylidene]benzeneamine, (PNCHP), which is the subject of Chapters 2 through 6. Chapter 2 - The ligand PNCHP reacts with [Mo(CO)3(1,3,5-cycloheptatriene)] to give the complex fac-[Mo(CO)3(PNCHP-K3 P,N,P)] which readily isomerises to mer-[Mo(CO)3(PNCHP-K3P,N,P)]. Kinetic studies on the isomerisation in acetone yielded the first-order forward rate constants (k1) 1.22x10 -5, 4.18x10 -5, 1.72X10 -4 and 4.89x10 -4 s-1 at 19.5, 29.7, 40.0 and 49.5 °C respectively, with thermodynamic activation parameters ΔH 1‡ and ΔS1‡ of 95 kJ mol-1 and -14.1 J mol-1 K-1 respectively. The related complex fac-[Mo(CO)3(PNHCH2P-K3P,N,P)] (PNHCH2P = 2-(diphenylphosphino)-N-[(2-diphenylphosphino)benzyl]benzeneamine does not undergo isomerisation. The complex cis-[Cr(CO)4(PNCHP-K2N,P)] reacts with sulfur to give cis-[Cr(CO)4(SPNCHP-K2N,P)] and reacts with methyliodide under an atmosphere of carbon monoxide to yield the anion [Cr(CO)5I]-. Chapter 3 - The complexes [M(CO)3(PNCHP-K3P,N,P)] (M = Cr, Mo or W), containing a terdentate PNCHP ligand, react with H+ to give the protonated products [M(CO)3{PN(H)CHP-k2P,P-η2(C=N)}]+, where the imino group has 'slipped' from a K1N to a η2(C=N) coordination mode as a result of the protonation of the nitrogen atom. When the acid is HC1 the above cation [M(CO)3{PN(H)CHP-K2P,P-η2(C=N)}]+ (M = Mo or W) converts to cis-[M(CO)2C12(PNHCH2P-K3P,N,P)]. In this unusual reaction the imine group of the PNCHP ligand has been reduced to an amine concurrently with the two electron oxidation of the metal. In contrast, on reaction of cis-[Cr(CO)4(PNCHP-K2N,P)] with H+, the bidentate PNCHP ligand dissociates from the metal resulting in cyclisation of the ligand to give a phosphonium salt. Chapter 4 - PNCHP favours terdentate coordination with Pd(II) and Pt(II). The complexes [Mcl(PNCHP-K3.P,N,P)]Cl and [Pd(CH3)(PNCHP-K3P,N,P)]Cl are synthesised starting with [MCl2(1,5-cyclooctadiene)] and [M(CH3)Cl(1,5-cyclooctadiene)], respectively. The ionic chlorides can be exchanged with BF4- using AgBF4. Abstraction of the covalent chloride with AgBF4 in the presence of acetonitrile yields [Pt(CH3CN)(PNCHP-K3P,N,P)]2+. The acetonitrile ligand of this dication can be substituted with triphenylphosphane, 2-picoline, or 3-picoline. The reaction of [Pt(CH3CN)(PNCHP-K3P,N,P)]2+. with 1,10-phenanthroline, 2,2'-bipyridine, bis(diphenylphosphino)ethane or 2,2':6',2"-terpyridine (L-L) yields complexes of the type [Pt(L-L)(PNCHP-K3P,N,P)]2+ - the first five-coordinate platinum(II) dications. Chapter 5 - The complex [RhCl(PNCHP-K3P,N,P)] is synthesised by reacting the PNCHP ligand with 0.5 equivalents of [{RhCl(1,5-cyclooctadiene)}2]. This extremely reactive compound undergoes oxidative addition of dichloromethane and chloroform to yield complexes of the type [RhCl2(R)(PNCHP-K3P,N,P)] (R = CH2Cl or CDCl2). Addition of carbon monoxide to [RhCl(PNCHP-K3P,N,P)] results in the adduct [RhCl(CO)(PNCHP-k3P,N,P)] which is in equilibrium with square planar complex [Rh(CO)(PNCHP-K3P,N,P)]Cl. The coordinated chloride ligand of [RhCl(PNCHP-K3P,N,P)] can be substituted with tetrahydrofuran, acetonitrile or triphenylphosphane. Chapter 6 - The triosmium clusters [Os3(CO)11(CH3CN)] and [Os3(CO)10(CH3CN)2] react with PNCHP to give [{Os3(CO)11}2(PNCHP-K2P,P)] (containing PNCHP bridging equatorially two osmium triangles), two coordination isomers of [Os3(CO)11(PNCHP-K1P)] and 1,1-[OS3(CO)10(PNCHP-K2P,P)], respectively. When 1,1-[Os3(CO)10(PNCHP-K2P,P)] is reacted with one equivalent of trimethylamineoxide the major product is [OS3(μ-H)(CO)7(μ3-PNCP)], in which the imine hydrogen of PNCHP has migrated to the osmium cluster and PNCP is left to act as a triply bridging nine-electron donor. Two geometrical isomers of [Os3(μ-H)(CO)8(μ2-PNCP)] are found as minor products, with PNCP acting as a doubly bridging seven-electron donor ligand.
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    [Pi]-loaded rhenium complexes : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry at Massey University, Palmerston North, New Zealand
    (Massey University, 2000) Steedman, Andrew
    A range of rhenium(VII) tris(imido) complexes, XRe(NR)3 (X=Me3SiO, R=Ar'; X=Cl, R=Ar', mes, Ar), have been synthesized either from [ReO4]-, RNH2 (R=Ar', mes, Ar), Et3N and Me3SiCl or Re(NR)2Cl3(py), RNH2 (R=Ar', Ar) and Et3N. An X-ray crystal structure of Me3SiORe(NAr')3 and ClRe(NAr)3 showed a slightly bent Re-N-C angle (158.8(5)° and 168.8(7)° respectively) and short Re-N distances (1.749(6)Å and 1.758(7)Å). Mixed tris(imido) complexes, ClRe(NR)2(NR') (R=Ar, R'=Ar, p-tol; R=Ar, R'=Ar, p-FC6H4, p-NO2C6H4, p-tol, AMP, o-ClC6H4, m-ClC6H4, o-tBuC6H4) have been synthesized from Re(NR)2Cl3(py) (R=Ar', Ar), R'NH2 (R'= Ar, p-tol, Ar', p-FC6H4, p-NO2C6H4, AMP, o-ClC6H4, m-ClC6H4, o-tBuC6H4) and Et3N. An X-ray crystal structure of ClRe(NAr)2(NAr') showed near linear Re-N-C angles (165(2)-172.5(19)°) and short Re-N distances (1.70(2)-1.766(19)Å). The crystal structure of ClRe(NAr)2(N-o-tBu) showed 2 near linear Re-N-Ar angles (172.4(2)° and 171.2(2)°) and one bent Re-N-o-tBu angle (160.8(2)°). Intermolecular imido ligand exchange was shown to occur slowly at room temperature between NAr' and Nmes. However, exchange between NAr' and NAr required heating to 60°C for exchange to occur. A chiral tetrahedral complex, ClRe(NAr')(NAr)(N-o-tBu), was synthesized from Re(NAr')(NAr)Cl3(py), o-tBuC6H4NH2 and Et3N. Alkyl/aryl derivatives of the mixed tris(imido) complexes, R"Re(NR)2(NR') (R=Ar', Ar, R'-Ar', Ar, R"=Me, p-tol, CH2Ph), have been synthesized from ClRe(NR)2(NR') (R=Ar, R'=Ar'; R=Ar', R'=Ar) and the Grignard, R"MgX (R"=Me, p-tol, X=Br; R"=CH2Ph, X=Cl). An X-ray crystal structure of MeRe(NAr)2(NAr') showed near linear Re-N-C angles (168.5(3)-171.2(3)°) and short Re-N lengths (1.753(4)-1.763(4)Å). The Re-N-Ar' angle was found to be ~ 10° larger than those found for tris(Ar'-imido) Re(VII) tetrahedral complexes. An oxo-bridging species, [Re(NAr)2(p-tol)(µ-O)]2, was isolated presumably from the hydrolysis of p-tolRe(NAr)3. The crystal structure of [Re(NAr)2(p-tol)(µ-O)]2 showed the rhenium atoms to be in a distorted square pyramidal geometry, as indicated by the Re-O bond distances (1.948(2) and 1.985(3)Å). Bis(imido) complexes, Re(NR)(NR')Cl3(py) (R=Ar', R'=Ar', Ar; R=R'=Ar), were synthesized from ClRe(NR)2(NR') (R=Ar', R'=Ar', Ar; R=Ar, R'=Ar', Ar) and pyHCl. An X-ray crystal structure of Re(NAr')2Cl3(py) showed near linear Re-N-C angles (171.8(12) and 174.4(3)°) and short Re-N distances (1.734(18) and 1.760(14)Å). The Cl ligands in the cis positions to the imido ligands are bent away from the imido ligands at an angle of 166.10(19)°. Amido complexes, p-tolNHRe(NR)(NR')(NR"), have been synthesized from ClRe(NR)(NR')(NR") (R=R'=Ar, R"=Ar, o-tBu; R=Ar, R'=Ar', R"=o-tBu) and LiNHp-tol. An X-ray crystal structure of p-tolNHRe(NAr)3 showed a bent Re-NH-C angle (129.6(3)°) typical of amido nitrogens. A range of Re(V) tris(imido) complexes, [Re(NR)2(NR')]- (R=R'=Ar'; R=Ar, R'=Ar', Ar, o-tBu), have been synthesized from XRe(NR)2(NR') (X=Me3SiO, Cl) and elemental sodium. These anions were found to be very sensitive both in solution and as solids. An X-ray crystal structure of [Re(NAr')3]- showed the complex to possess a 2-fold axis of symmetry through one of the imido ligands. The counter ion was found to be Na+ with 6 coordinated molecules of thf. The anions were found to react with ClSnMe3 and ClAuPPh3 to form Re-Sn (Me3SnRe(NAr)2(NR), R=Ar', Ar, o-tBu) and Re-Au (Ph3PAuRe(NR)2(NR'), R=R'=Ar'; R=Ar, R'=Ar', Ar) complexes respectively. The crystal structure of Me3SnRe(NAr)3 and Me3SnRe(NAr)2(NAr') showed near linear Re-N-C angles (170.2(5)-172.9(2)°) and short Re-N distances (1.752(6)-1.779(3)Å). Rhenium(VI) dimeric complexes were synthesized from the anion, [Re(NR)2(NR')]- (R=R'=Ar'; R=Ar, R'=Ar', Ar, o-tBu) and ferrocenium, [Cp2Fe]+. Both Re2(NAr')6 and Re2(NAr)4(NAr')2 contain bridging imido ligands, while Re2(NAr)6 and Re2(NAr)4(N-o-tBu)2 contain only terminal imido ligands, as indicated by proton NMR. An X-ray crystal structure of [Re(NAr')2(µ-NAr')]2 showed slightly bent terminal imido angles (156.2(3) to 168.8(3)°), short Re-N(terminal) distances (1.750(4) to 1.763(3)Å) and typical Re-N(bridging) distances of 1.951-1.959(4)Å. The average Re-Re distance of 2.735(4)Å indicates a weak metal-metal interaction. The crystal structure of Re2(NAr)6 showed the complex adopts an ethane-like geometry with the imido ligands arranged in a staggered orientation. The Re-Re bond lies on a crystallographic S6 axis. A Re(VII) cation, [Re(NAr)3]+, is implicated on the basis of formation of a ferrocene complex, (C5H5)Fe(C5H4)Re(NAr)3.