15573-39-4

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)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 oftrans-[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.

The present invention relates to a phosphine precursor for the preparation of a quantum dot, and a quantum dot prepared therefrom. Using the phosphine precursor for the preparation of a quantum dot of the present invention, a quantum dot with improved luminous efficiency and higher luminous color purity can be provided.

Reduction of [CpArFe(μ-Br)]2 (1, CpAr = C5(C6H4-4-Et)5) by potassium napthalenide, followed by the addition of white phosphorus, affords [K(18-c-6){CpArFe(η4-P4)}] (2, 18-c-6 = [18]crown-6), which features a planar cyclo-P42- ligand. The related diiron complex [Na2(THF)5(CpArFe)2(μ,η4:4-P4)] (3) was obtained by reducing 1 with sodium amalgam in the presence of P4. Protonation of 3 affords [Na(THF)3][(CpArFe)2(μ,η4:4-P4)(H)] (4), while the reaction of 3 with trimethylchlorosilane gives the nortricyclane compound P7(SiMe3)3 as the main product.

A completely inorganic version of one of the most famous organophosphorus compounds, triphenylphosphine, has been prepared. A comparison of the crystal structures of inorganic triphenylphosphine, PBaz3 (where Baz=B3H2N3H3) and PPh3 shows that they have superficial similarities and furthermore, the Lewis basicities of the two compounds are remarkably similar. However, their oxygenation and hydrolysis reactions are starkly different. PBaz3 reacts quantitatively with water to give PH3 and with the oxidizing agent ONMe3 to give the triply-O-inserted product P(OBaz)3, an inorganic version of triphenyl phosphite; a corresponding transformation with PPh3 is inconceivable. Thermodynamically, what drives these striking differences in the chemistry of PBaz3 and PPh3 is the great strength of the B?O bond.

The reactions of R2P-P(SiMe3)Li (R = tBu, iPr, iPr2N) with [Cp2MCl 2] (M = Zr, Hf), [Cp*z.ast;CpZrCl2] and [CpZrCl 3] yielded polyphosphorus (mainly hexaphosphorus) compounds which can be viewed as intermediates between R2P-P(SiMe3)Li and derivatives of 1,2,3,4-tetraphosphabicyclo[1.1.0] butane. Thus R 2P-P(SiMe3)Li can act as a building block for the formation of the P2 ligand and the R2P-P(P2) and R2P-P(P2)P-PR2 moieties. Solid state structures of zirconium(IV) and hafnium(IV) complexes with R2P- P(P2) and R2P-P(P2)P-PR2 ligands were established by X-ray studies.

We have studied the speciation of P(SiMe3)3 during the synthesis of colloidal InP quantum dots in the presence of proton sources. Using 31P NMR spectroscopy, we show H3-nP(SiMe 3)n formation on exposure of P(SiMe3) 3 to a variety of protic reagents including water, methanol, and carboxylic acid, corroborating observations of P(SiMe3)3 speciation during the hot injection synthesis of InP QDs. Quantitative UV-vis comparisons between InP growth from P(SiMe3)3 and HP(SiMe3)2 show unambiguously that when total H +-content is accounted for, particle size, size dispersity, and concentration are indistinguishable for these two reagents. The dual role of myristic acid in P-Si bond cleavage and as a source of the myristate anion, an essential component of the quantum dot surface, is interrogated using tetrabutylammonium myristate, confirming that it is the protons that are responsible for increased quantum dot polydispersity. Together these data support the existence of a competing acid-catalyzed pathway in the conversion of P(SiMe3)3 to InP and demonstrate its impact. By preventing a constant solute supply and affecting the concentration of quantum dot surfactant over the course of the reaction, the existence of competing precursor conversion pathways is detrimental to formation of monodisperse colloids, explaining much of the irreproducibility in InP quantum dot syntheses to date.

The reaction of Cp2Zr(Cl) (1) with phenylacetylene in boiling toluene yields regiospecifically the insertion product (Z)-Cp2Zr(Cl) (2) which reacts with MeLi or nBuLi by forming the corresponding alkyl-substituted zirconocene derivatives (Z)-Cp2Zr(R) .The attempt to prepare the C(Ph)=C(H)P(SiMe3)2- ligand directly from Li(THF)2P(SiMe3)2 and phenylacetylene yields HP(SiMe3)2 and LiCPh.An X-ray structure determination of 2 and 3 was carried out. Key Words: Alkyne insertion / Ethenyl ligands, 2-(silylphosphanyl)- / Zirconocenes / Zirconium complexes / Phosphido ligands

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The compounds H2Si2 and 2 were prepared and characterized by 29Si NMR, 31P NMR, IR and Raman spectroscopy.After thermolysis of these compounds no cyclic silylphosphanes could be detected in the reaction mixture, although this did contain P(SiMe3)3.

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