Tris(hydroxypropyl)phosphine Oxide: A Chiral Three-Dimensional Material with Nonlinear Optical Properties

The achiral C_(3v) organic phosphine tris(hydroxypropyl)phosphine oxide (1) crystallizes in the unusual chiral hexagonal space group P6_3. The structure is highly ordered because each phosphine oxide moiety forms three hydrogen bonds with adjacent hydroxy groups from three different molecules. The properties of the crystals and the presence of hydrogen bonding interactions were investigated using single crystal Raman spectroscopy. The crystals show nonlinear optical properties and are capable of efficient second harmonic generation

Combustive approach for measuring total volatile phosphorus content in landfill gas

A technique was developed to measure the total gaseous phosphorus content in biogas. The amount of air needed for a neutral to oxidising flame was mixed with the biogas. The gas mixture was burnt in a closed quartz burner and the combustion gasses were bubbled through a nitric acid solution. The phosphate content in the bubbling liquid was determined with sector field ICP-MS. The technique was validated in the lab with phosphine. Afterwards the set-up was installed on a landfill. The total gaseous phosphorus content in the landfill gas, measured with the combustive technique, ranged from 1.65 to 4.44 mug P/m(3). At the same time the phosphine concentration in the landfill gas was determined gas chromatographically (GC). The phosphine (PH3) content measured with GC ranged from 7.6 to 16.7 mug PH3-P/m(3). Since the phosphine-P content (GC) was consistently higher than the total gaseous phosphorus content (burner/ICP-MS), the hypothesised presence of highly toxic gaseous phosphorus compounds other than phosphine could not be demonstrated

Phosphine-porphyrin conjugates : a thesis presented in partial fulfilment of the requirements for the degree of Masterate of Science in Chemistry at Massey University, New Zealand

The research carried out in this thesis comprises an investigation into the synthesis and characterisation of a variety of complexed phosphine-aldehydes, complexed phosphinoporphyrins, and phosphinoferrocene conjugates. The porphyrin and phosphine moieties are linked together via the vinyl group, a product of Wittig chemistry. In general, functionalisation occurs at the β-pyrrolic position of the porphyrin and at the para position of a phenyl group on the phosphine. Chapter One introduces the properties of porphyrins and the triphenylphosphine ligand, as well as a brief review on the types of functionalised triphenylphosphines. A brief review of existing phosphinoporphyrins is also discussed. The proposal for using the vinylic linking group (and hence Wittig chemistry) to connect the porphyrin and the phosphine moieties is also described. Chapter Two outlines the synthesis of the 4-(diphenylphosphino)benzaldehyde (5) ligand, which is a necessary precursor for the Wittig reaction with meso-tetraphenylporphyrin (TPP) phosphonium salt (1). It was discovered that the Wittig reaction of (1) with (5) led to the synthesis of the product of oxidation, phosphinoporphyrin oxide (7), instead of the desired phosphinoporphyrin (6). Therefore an alternative scheme was pursued - complexation before the Wittig reaction. Hence the remainder of the chapter describes both the synthesis and characterisation aspects of five transition metal complexes of (5). These include complexes of gold, ruthenium, tungsten, and platinum. Chapter Three describes the synthesis and characterisation of a variety of novel complexed phosphinoporphyrins, including two bis-phosphinoporphyrin complexes. This was achieved by utilising Wittig chemistry of TPP phosphonium salt (1) with the appropriate complexed phosphine-aldehyde. In each case, optimisation of the Wittig conditions was required in order to obtain the sterically and thermodynamically favoured trans isomer. Chapter Four extends the phosphinoporphyrin chemistry by investigating the synthesis of a novel phosphinoporphyrin trimer. In order to achieve this, a phosphine tris-aldehyde was synthesised. This chapter focuses on the synthesis and characterisation of tris(4-formylphenyl)phosphine oxide (20). The results of the Wittig reaction of (20) with TPP phosphonium salt (1) are also described. Chapter Five demonstrates the versatility of both the Wittig and phosphine chemistry. In this chapter, the synthesis of phosphinoferrocenes via Wittig chemistry is investigated. The ferrocene and phosphine moieties are linked via the vinyl group, in a similar manner as the phosphinoporphyrins. In this case, functionalisation occurs at the para position of a phenyl group of the phosphine to the cyclopentadienyl ring of the ferrocene. A phosphinoferrocene monomer, (24), was synthesised by Wittig reaction of a ferrocene phosphonium salt (22) with (5). Both the synthesis and characterisation of this compound is reported. Also described is the attempted synthesis of a phosphinotrisferrocene via Wittig reaction of (22) with (20). Chapter Six contains a brief summary of the results obtained during this study, and also mentions future research to be pursued in this field of study

Interaction of some extreme-pressure type lubricating compounds with an iron surface

An iron surface was exposed to the extreme-pressure type lubricant benzyl chloride, dichlorophenyl phosphine, dichlorophenyl phosphine sulfide, ophenyl phosphine oxide. Iron, in the sputter-cleaned state, was exposed to these materials statically and during dynamic friction experiments. With benzyl chloride only chlorine adsorbed to the surface, and with dichlorophenyl phosphine no adsorption occurred, while the addition of sulfur to that same molecular structure resulted in the promotion of carbon and chlorine adsorption. substitution of oxygen for sulfur in the dichlorobenzyl phosphine molecule resulted in carbon, chlorine, and oxygen adsorption. With none of the phosphorus containing molecules was phosphorus detected on the surface. Sliding in an atmosphere of benzyl chloride promoted adsorption of chlorine to the iron surface. Increases in load resulted in a decrease in the surface concentration of iron chloride

Bridged [2.2.1] bicyclic phosphine oxide facilitates catalytic γ-umpolung addition-Wittig olefination.

A novel bridged [2.2.1] bicyclic phosphine oxide, devised to circumvent the waste generation and burdens of purification that are typical of reactions driven by the generation of phosphine oxides, has been prepared in three steps from commercially available cyclopent-3-ene-1-carboxylic acid. The performance of this novel phosphine oxide was superior to those of current best-in-class counterparts, as verified experimentally through kinetic analysis of its silane-mediated reduction. It has been applied successfully in halide-/base-free catalytic γ-umpolung addition-Wittig olefinations of allenoates and 2-amidobenzaldehydes to produce 1,2-dihydroquinolines with good efficiency. One of the 1,2-dihydroquinoline products was converted to known antitubercular furanoquinolines

Phosphine-Catalyzed Annulations of Azomethine Imines: Allene-Dependent [3 + 2], [3 + 3], [4 + 3], and [3 + 2 + 3] Pathways

In this paper we describe the phosphine-catalyzed [3 + 2], [3 + 3], [4 + 3], and [3 + 2 + 3] annulations of azomethine imines and allenoates. These processes mark the first use of azomethine imines in nucleophilic phosphine catalysis, producing dinitrogen-fused heterocycles, including tetrahydropyrazolo-pyrazolones, -pyridazinones, -diazepinones, and -diazocinones. Counting the two different reaction modes in the [3 + 3] cyclizations, there are five distinct reaction pathways—the choice of which depends on the structure and chemical properties of the allenoate. All reactions are operationally simple and proceed smoothly under mild reaction conditions, affording a broad range of 1,2-dinitrogen-containing heterocycles in moderate to excellent yields. A zwitterionic intermediate formed from a phosphine and two molecules of ethyl 2,3-butadienoate acted as a 1,5-dipole in the annulations of azomethine imines, leading to the [3 + 2 + 3] tetrahydropyrazolo-diazocinone products. The incorporation of two molecules of an allenoate into an eight-membered-ring product represents a new application of this versatile class of molecules in nucleophilic phosphine catalysis. The salient features of this protocol—the facile access to a diverse range of nitrogen-containing heterocycles and the simple preparation of azomethine imine substrates—suggest that it might find extensive applications in heterocycle synthesis

Elastomer-modified phosphorus-containing imide resins

Phosphine oxide-containing polyimide resins modified by elastomers, are disclosed which have improved mechanical properties. These products are particularly useful in the production of fiber or fabric-reinforced composites or laminates

Towards the fabrication of phosphorus qubits for a silicon quantum computer

The quest to build a quantum computer has been inspired by the recognition of the formidable computational power such a device could offer. In particular silicon-based proposals, using the nuclear or electron spin of dopants as qubits, are attractive due to the long spin relaxation times involved, their scalability, and the ease of integration with existing silicon technology. Fabrication of such devices however requires atomic scale manipulation - an immense technological challenge. We demonstrate that it is possible to fabricate an atomically-precise linear array of single phosphorus bearing molecules on a silicon surface with the required dimensions for the fabrication of a silicon-based quantum computer. We also discuss strategies for the encapsulation of these phosphorus atoms by subsequent silicon crystal growth.Comment: To Appear in Phys. Rev. B Rapid Comm. 5 pages, 5 color figure

Structural studies on the interactions of a P2N tridentate ligand with copper(I) silver(I) and S : a dissertation presented in partial fulfilment of the degree of Master of Philosophy at Massey University

This thesis presents a study of the coordination chemistry, chemical reactivity, spectroscopy, structure and bonding of the hybrid polydentate ligand 2-(diphenylphosphino)-N-[2-(diphenylphosphino)benzylidene]benzeneamine (PNCP) with copper(I), silver(I) and sulfur. The hybrid polydentate (PNCP) ligand contains two inequivalent phosphorus (soft) and one nitrogen (hard) donor atoms, Chapter One is a brief overview of tertiary phosphines used as monodentate, bidentate, tridentate and polydentate ligands with transition metals. In Chapter Two, the preparation structure and characterisation of PNCP have been studied. Reactions of PNCP with sulphur have been investigated and a small site selectivity for one of the P atoms noted. Experiments have also included selective synthesis of the unsymmetrical mono-sulphide tertiary phosphine ligands SPNCP, PNCPS and of the di-sulfide SPNCPS ligand, as well as a study on the molecular structure of the 3-coordinate complex, [Cu(SPNCPS)]CIO₄. In Chapter Three the preparation of a series of copper(I) complexes of the general formula [Cu(PNCP)ClO₄] and [Cu(PNCP)L]ClO₄ (L- ligands containing S, N donor atoms) have been reported. The crystal structure of [Cu(PNCP)ClO₄] has been determined, and shows PNCP acts as a tridentate ligand coordinated to copper(I) via two phosphorus and one nitrogen donor atoms. The copper(I) atom has a distorted tetrahedral environment with two short Cu-P bonds and a slightly long Cu-N bond. In Chapter Four, studies on the preparation of the mononuclear complex [Ag(PNCP)ClO₄] and the dinuclear complex [Ag(PNCP)(SCN)]₂ are presented. Both complexes were characterized by a variety of physicochemical techniques. The tridentate behaviour of PNCP in the complex [Ag(PNCP)ClO₄] was established but the Ag-N bond was long and weak. In the complex [Ag(PNCP)(SCN)]₂ the Ag-N bond not exist and PNCP acts as a bidentate ligand