Synthesis of 3-stannyl and 3-silyl propargyl phosphanes and the formation of a phosphinoallene

The group 14 chloropropargyls R3ECCCH2Cl (R3E = Bu3Sn, Ph3Sn, Me2PhSi, iPr3Si, nPr3Si, nBu3Si), obtained by a modified literature procedure, react with LiPPh2 to afford the novel propargyl phosphanes Ph2PCH2CCER3 in high yield, as viscous oils; (Me3Si)2PCH2CCSiPhMe2 is similarly obtained from LiP(SiMe3)2. In contrast, the reaction of PhCCCH2MgCl with ClP(NEt2)2 fails to produce a comparable propargyl phosphane, but generates preferentially (>70%) the novel phosphinoallene (Et2N)2PC(Ph)=C=CH2, which is characterised spectroscopically, and through its reaction with HCl. The coordination chemistry of representative phosphanes is explored with respect to platinum and palladium for the first time

Through-conjugation of two phosphaalkyne (‘CP’) moieties mediated by a bimetallic scaffold†

Through-conjugation of two phosphaalkyne moieties within an isolable molecule is demonstrated for the first time with the synthesis of [{Ru(dppe)2}2{μ-(CC)2C6H4-p}(CP)2], via base induced desilylation of [{Ru(dppe)2}2{μ-(CC)2C6H4 p}Cl2]. The nature of the cyaphide ligands and their influence upon the bimetallic core are studied electrochemically

Ruthenaphosphaalkenyls: synthesis, structures, and their conversion to η2‑phosphaalkene complexes

The ruthenaphosphaalkenyls [Ru{PCH-(SiMe2R)}Cl(CO)(PPh3)2] (R = Me, Ph, Tol) have been prepared in good yield by the facile hydroruthenation of the respective phosphaalkynes, RMe2SiCP, with [RuHCl(CO)-(PPh3)3]; all three compounds have been structurally characterized in the solid state. Complemented by DFT studies of these, and the precedent [Ru{PCH(tBu)}Cl(CO)(PPh3)2], the phosphaalkenyl moieties have been established unequivocally to behave as one-electron donors to the coordinately unsaturated, 15-electron “RuCl(CO)(PPh3)2” fragment, corroborating an earlier demonstration of nucleophilic character at phosphorus within the tert-butyl system. Notwithstanding, the ruthenaphosphaalkenyls are shown to react with the nucelophiles Lipz′ (pz′ = pz, pz*, pzH,CF3, pzMe,CF3) to afford the η1,η2-chelated pyrazolylphosphaalkene complexes [Ru{η1-N:η2-P,C-P(pz′)CH(R)}(CO)(PPh3)2], which feature a three-membered metallacyclic (Ru−C−P) core. The nature of these novel compounds is discussed, alongside preliminary insight into the process by which they are formed

Diphosphametacyclophanes: structural and electronic influences of substituent variation within a family of bis(diketophosphanyl) macrocycles

The condensation of MeP(SiMe3)2 with a series of 5-substituted isophthaloyl chlorides (5-R′C6H3-2,6-{C(O)Cl}2) affords the diphosphametacyclophanes m-{-C(O)-C6H3-5-R′-(C-(O)PMe)}2 (R′ = I, Me, tBu, Ph, and p-NCC6H4); the analogues m-{-C(O)-C5H3N-(C(O)PMe)}2 and m-{-C(O)-C6H4-(C(O)-PPh)}2 are similarly obtained in preference to higher oligomers, in contrast to precedent reports. The cyclophanes all adopt butterfly-like conformations in the solid state with the P-organyl substituents adopting mutually exo arrangements. Structural and computatiosnal data suggest the nature of the 5-R substituent is key in directing the inter-ring angle and the extent of LUMO stabilization about the diketophophanyl scaffold. The latter is substantiated by UV/vis pectroscopy and cyclic voltammetry, which demonstrate these cyclophanes to be appreciably comparable to the diketophosphanyl systems commonly explored in the context of organic electronic materials; intriguingly, the distinct dikeophosphanyl moieties within the macrocycles appear effectively “insulated” by the macrocycle geometry, rather than acting as a through-conjugate

Synthesis and electronic structure of the first cyaphide-alkynyl complexes

The novel complexes trans-[Ru(dppe)2(CCR)(CP)] (R = CO2Me, C6H4OMe), the first to incorporate cyaphide as part of a conjugated system, are obtained in facile manner. The electronic structure of these compounds is probed by X-ray, DFT and UV/Vis studies

Phosphacycloalkyldiones: synthesis and coordinative behaviour of 6- and 7-member cyclic diketophosphanyls

Glutaryl and adipoyl chlorides undergo facile condensation with the bis(silyl)phosphanes RP(SiMe3)2 (R = Me, nBu, tBu, Ph, Mes) to afford exclusively the phosphacycloalkyldiones (CH2)n(C[double bond, length as m-dash]O)2PR (n = 3, 4). Characterised spectroscopically and, for R = Ph, Mes (n = 3) crystallographically, the macrocycles are conformationally fluxional in solution and appreciably moisture sensitive. Though seemingly resistant to chemical oxidation at phosphorus, coordination is readily achieved, as illustrated by isolation of trans-[Pt(PEt3){P(Ph)(CO)2(CH2)3}Cl2] and a series of tungsten pentacarbonyl complexes, which are characterised crystallographically and by infrared and NMR spectroscopy. Together, these data suggest the macrocycles to be relatively weak σ-donors with no appreciable π-acceptor character

Controlled reactivity of terminal cyaphide complexes: Isola-tion of the 5-coordinate [Ru(dppe)2(CP)]+

The novel cyaphide complex trans-[Ru(dppe)2Me(CP)] is obtained in excellent yields and exhibits the first instance of con-trolled reactivity of any terminal-cyaphide complex. Its treatment with ZnX2 / PPh3 effects selective metathesis of the methyl moiety to afford the unprecedented halo-cyaphide complexes trans-[Ru(dppe)2(X)(CP)] (X = Cl, Br, I), which are structurally characterized (X = Cl, Br). Exemplified with the trans-bromide, these compounds are susceptible to substitution of the halides by nucleophilic reagents – illustrated with Me2Mg – and also readily undergo halide abstraction by TlOTf to afford the first hypo-coordinate cyaphide complex, viz. [Ru(dppe)2(CP)].OTf, which is isolable in bulk and exhibits good stability. NMR spectroscopic and crystallographic data reveal the latter to adopt a square pyramidal geometry with an accessible coordinate vacancy, which is susceptible to the addition of nucleophiles. This is illustrated analytically by reactions with Me2Mg and LiCCPh, and with its facile bulk carbonylation to afford trans-[Ru(dppe)2(CO)(CP)]+

Hydrochlorination of ruthenaphosphaalkenyls: unexpectedly facile access to alkylchlorohydrophosphane complexes

The novel ruthenaphosphaalkenyls [Ru{P═C(H)SiMe2R}Cl- (CO)(PPh3)2] (R = p-C6H4CF3, nBu) have been prepared for the first time, and studied alongside precedent analogues (R = Me, Ph, p-tol) for their reactions with HCl. In contrast to chemistry defined for the tert-butyl congener [Ru{P═C(H)tBu}Cl(CO)(PPh3)2], which initially adds a single equivalent of HCl across the Ru−P linkage, all five silyl derivatives undergo spontaneous addition of a second equivalent to afford [Ru{η1-PHCl−CH2SiMe2R}Cl(CO)(PPh3)2], extremely rare examples of coordinated “PHXR” type ligands. Where R = SiMe3, a distorted octahedral geometry with a conformationally restricted “PHXR” ligand is observed crystallographically; this structure is appreciably retained in solution, as determined from multinuclear NMR spectroscopic features, which include a Karplus-like PPh3−Ru−P−H spin−spin coupling dependence. Computational data suggest a silyl-induced increase in negative charge density at the phosphaalkenic carbon, rather than an intrinsic thermodynamic driver, as the likely origin of the disparate reactivity

Existential Communication and Leadership

The aim of this article is to introduce and explain a number of important existentialist philosophers and concepts that we believe can contribute to a critical approach to leadership theory. Emphasis is placed on understanding the nature of communication from an existentialist perspective and so Jaspers' conceptualization of existential communication is introduced along with important related concepts that may be regarded as important facets of leader communication including Being-in-the-world, the Other, intersubjectivity, dialogue and indirect communication. Particular attention is paid to Buber's ideas on communication as relationship and dialogue. Throughout, reference is made to contemporary, and what is often regarded as orthodox, thinking regarding the centrality of communication to leadership practice as a means by which to highlight the salience of an existentialist analysis

Sheep Updates 2005 - Part 5

This session covers eleven papers from different authors; MARKET INFORMATION 1. Crystal Spring - Crystal clear and consistant, Geoff Duddy, Livestock Officer (Sheep & Wool) Yanco, NSW, Brent McLoud, (Product Development Officer) Cowra, NSW, John Sullivan, J.J Dresser and Co (Agent), Woodstock, NSW 2. An overview of Recent Developments in Dark and Medullated Fibre Testing, T.J. Mahar, A. Balasingam, AWTA Ltd 3. Opportunities and Implications for Wool Producers of the TEAM3 Prediction Equations, J.H. Stanton12 K.M.S. Curtis1 , 1Department of Agriculture Western Australia, 2 Curtin University, WA 4. Premiums and Discounts for Fibre Properties in Superfine Wool, Now and in the Future?, K.M.S. Curtis1, P.R. Lamb2, 1 Department of Agriculture Western Australia, 2Lambshift Consulting, Geelong VIC FEEDLOTTING 5. Manure in sheep feedlots: problem or opportunity?, Eliza Dowling, Ned Crossley Department of Agriculture , Western Australia, Surrender Mann, Chemistry Centre (WA), East Perth WA, 6. The State of Lamb Confinement Feeding in WA, Ned Crossley, Department of Agriculture, Western Australia 7. Finishing lambs in a feed lot - Is it profitable?, Lucy Anderton, Department of Agriculture, Western Australia 8. Repeated live weights can mardinally improve prediction of compliance to markey specifications, Mattew Kelly, Andrew Swan, CSIRO livestock industries, Ian McFarland, Department of Agriculture Western Australia. WELFARE 9. Mulesing accreditation - to be or not to be? Di Evans, Department of Agriculture, Western Australia. 10. The Economic and Research Implications of managing Merino Sheep with out Mulesing, K. Bell, Sheep Management and Production Consultants, North Fremantle WA, D. Sackett, Homes Sackett and Associates, Wagga Wagga NSW 11. How do lambs fare during curfew, Dr Robin Jacob, Department of Agriculture, Western Australi