Abstract: The present invention is generally directed to luminescent lanthanide compounds with phosphine oxide, phosphine oxide-sulfide, pyridine N-oxide, and phosphine oxide-pyridine N-oxide ligands. It also relates to electronic devices in which the active layer includes a lanthanide complex.

Abstract: The invention is directed to a phosphonate composition having flame retardant properties. The phosphonate composition of the invention has the general formula: wherein R1 and R2 are independently C1–C4 alkyl, R3 is H or C1–C4 alkyl, and R4 is linear or branched C9–C22 alkyl, C9–C22 cycloalkyl, C9–C22 aryl or C9–C22 aralkyl and n=0 or 1. The invention is also directed to a method of producing the phosphonate composition having flame retardant properties.

Abstract: This invention relates to processes for making phosphorus compounds R2P—X—PR2, R2P-M, R2P-L and R3P, and the novel cation R2P+(L)-X—P+(L)R2, where R represents an optionally substituted hydrocarbyl group, X represents a bridging group, L represents a leaving group and M represents an alkali metal atom. The invention relates further to a process for making a compound R2P-L from a compound R—H via a new process for making the compound R—Li followed by its reaction with a compound Hal2P-L. The compound R2P—X—PR2 is a ligand suitable for making catalysts for copolymerizing carbon monoxide and a olefinically unsaturated compound.

Abstract: Compounds of the formula I in which Ar is a group or unsubstituted or substituted cyclopentyl, cyclohexyl, naphthyl, biphenylyl or an O-, S- or N-containing 5- or 6-membered heterocyclic ring; R1 and R2 are C1-C20alkyl, OR11, CF3 or halogen; R3, R4 and R5 are hydrogen, C1-C20alkyl, OR11 or halogen; R6 is unsubstituted or substituted C1-C24alkyl, C2-C24alkyl, which is interrupted by O, S or NR14 and is unsubstituted or substituted; C2-C24alkenyl, uninterrupted or interrupted by O, S or NR14 and unsubstituted or substituted; unsubstituted or substituted C7-C24arylalkyl; C4-C24cycloalkyl, uninterrupted or interrupted by O, S and/or NR14; or C8-C24arylcycloalkyl; R11 is C1-C20alkyl, C3-C8cycloalkyl, phenyl, benzyl or C2-C20alkyl, interrupted by O or S and unsubstituted or substituted; R12 and R13 are hydrogen, C1-C20alkyl, C3-C8cycloalkyl, phenyl, benzyl or C2-C20alkyl, interrupted by O atoms and unsubstituted or substituted; or R12 and R13 together are C3-C5alkylene, uninterrupted or interrupted by O,

Abstract: The present invention relates to a process for preparing phosphites and their transition metal complexes and also to their use in catalytic processes.

Abstract: Novel compounds of phosphorus, of arsenic and of antimony can be used as ligands to form complexes of metals of transition group VIII which can be used in catalysts for hydroformylation, hydrocyanation, carbonylation, hydrogenations, oligomerization and polymerization of olefins and for metathesis.

Abstract: Compounds of the formula I (I), in which Ar is a group or unsubstituted or substituted cyclopentyl, cyclohexyl, naphthyl, biphenylyl or an O-, S- or N-containing 5- or 6-membered heterocyclic ring; R1 and R2 are C1-C20alkyl, OR11, CF3 or halogen; R3, R4 and R5 are hydrogen, C1-C20alkyl, OR11 or halogen; R6 is unsubstituted or substituted C1-C24alkyl, C2-C24alkyl, which is interrupted by O, S or NR14 and is unsubstituted or substituted; C2-C24alkenyl, uninterrupted or interrupted by O, S or NR14 and unsubstituted or substituted; unsubstituted or substituted C7-C24arylalkyl; C4-C24cycloalkyl, uninterrupted or interrupted by O, S and/or NR14; or C8-C24arylcycloalkyl; R11 is C1-C20alkyl, C3-C8cycloalkyl, phenyl, benzyl or C2-C20alkyl, interrupted by O or S and unsubstituted or substituted; R12 and R13 are hydrogen, C1-C20alkyl, C3-C8cycloalkyl, phenyl, benzyl or C2-C20alkyl, interrupted by O atoms and unsubstituted or substituted; or R12 and R13 together are C3-C5alkylene, uninterrupted or interrupted by

Abstract: Diphosphine of formula I R1R2P—H2C—Ar—CH2PR1R2??(I) are prepared by a process that comprises a) reacting a dimethyl compound of formula II H3C—Ar—CH3??(II) with a base and an N-substituted aminophosphorous halide to form bis(aminophosphinomethyl) compound of the formula III R3R4P—H2C—Ar—CH2—PR3R4??(III) b) reacting the compound of formula III with HCl to form bis(dichlorophosphinomethyl) compound of formula IV Cl2P—H2C—Ar—CH2—PCl2??(IV) and c) reacting the compound of formula IV with an organometallic reagent to give the product compound of formula I, wherein groups R1 and R2 are each, independently of one another, a substituted or unsubstituted aromatic, heteroaromatic or aliphatic hydrocarbon group and may have a covalent bond connecting them and Ar is a substituted or unsubstituted aromatic or heteroaromatic hydrocarbon group an R3 and R4 are each, independently of one another, an N-substituted alkylamino or arylamino group.

Abstract: Acrylic ester phosphonic acids of general formula (I), stereoisomers thereof and mixtures of these, wherein n is 1 or 2, on the condition that for n=1 R1 has the meaning and for n=2 R1 has the meaning R2 is a C1 to C12 alkylene radical, C4-C8 cycloalkylene radical or C7 to C15 alkylene phenylene radical; R3 is hydrogen, a C1 to C5 alkyl radical or a C1 to C5 O-alkyl radical; and R4, R5, independently of each other, each stand for a C1 to C5 alkyl radical or a C1 to C5 O-alkyl radical.

Abstract: One embodiment of the invention is a composition that comprises a radioactive 32P or 33P phosphine oxide molecule. The said composition is designed to bind to the transient potential receptor-M8 (TRP-M8) receptor of cells. The radioactive 32P or 33P phosphine oxide ligand may be used for radioreceptor binding studies and for diagnostic studies of cancerous tissues. The TRP-M8 receptor is selectively expressed in malignant tissues such as prostate cancer cells. Affinity of the 32P or 33P phosphine oxide ligand for the TRP-M8 receptor confers selectively and specificity in delivering lethal radiation to the diseased cells.

Abstract: A description is given of processes for the preparation of mono- and bisacylphosphines and of mono- and bisacylphosphine oxides and mono- and bisacylphosphine sulfides, which comprises first reacting organic P-monohalogenophosphines or P,P-dihalogenophosphines, or mixtures thereof, with an alkali metal or magnesium in combination with lithium, where appropriate in the presence of a catalyst, and then carrying out the reaction with acid halides and, in the case of the process for the preparation of oxides, carrying out an oxidation step and, in the case of the preparation of sulfides, reacting the phosphines so obtained with sulfur. It is characteristic, inter alia, that the processes are carried out without isolation of the intermediates.

Abstract: Non-C2-symmetric bisphospholane ligands and methods for their preparation are described. Use of metal/non-C2-symmetric bisphospholane complexes to catalyze asymmetric transformation reactions to provide high enantiomeric excesses of formed compounds is also described.

Abstract: The invention relates to a process for synthesizing an ionic metal complex represented by the general formula (1) or (5). This process includes reacting in an organic solvent a compound (corresponding to ligand of the complex) represented by the general formula (2) or (6) with a halogen-containing compound represented by the general formula (3) or (4), in the presence of a reaction aid containing an element selected from the group consisting of elements of groups 1-4 and 11-14 of the periodic table. It is possible by this process to easily and efficiently synthesize the ionic metal complex, which can be used as a supporting electrolyte for electrochemical devices, a polymerization catalyst of polyolefins and so forth, or a catalyst for organic synthesis.

Abstract: The invention relates to macromolecular hydrophilic photocrosslinkers having polymeric backbones of substituted ethylene groups carrying photoactive groups. The photocrosslinkers are capable of producing, when being exposed to light of determined wavelengths above 305 nm, radicals which are retained on the macromolecular photocrosslinkers and reacting so as to accomplish a crosslinked network structure. The invention further relates to the preparation of photocrosslinkers, their use in different aqueous systems and their utility in production of medical devices including ophthalmic lenses.

Abstract: Compounds of formula (I), wherein A is S or O; x is 0 or 1; a is SR10 or N(R11)(R12); R1 and R2 are C1-C24alkyl, OR10, CF3 or halogen; R3, R4 and R5 are hydrogen, C1-C24alkyl, OR10 or halogen; or two of the radicals R11 R21 R31 R4 and/or R9 together form C1-C2oalkylene uninterrupted or interrupted by O, S or NR13; R6, R11 R8 and R9 are hydrogen, C1-C24alkyl; C2-C24alkyl which is interrupted one or more times by non-consecutive O atoms and unsubstituted or substituted by OH and/or SH, or R6, R7, R8 and Rg are OR10; halogen; or phenyl unsubstituted or substituted one or more times by C-Calkyl; R10, R11 and R12 are e.g. hydrogen; X is e.g. (II), and R2; have one of the meanings given for R1 and R2; and R3′, R4′ and Rs′ have one of the meanings given for R3, R4 and R5; are suitable as photoinitiators, especially for irradiation with light of relatively long wavelengths.

Abstract: One embodiment of the invention is a composition that comprises a radioactive 32P or 33P phosphine oxide molecule. The said composition is designed to bind to the transient potential receptor-M8 (TRP-M8) receptor of cells. The radioactive 32P or 33P phosphine oxide ligand may be used for radioreceptor binding studies and for diagnostic studies of cancerous tissues. The TRP-M8 receptor is selectively expressed in malignant tissues such as prostate cancer cells. Affinity of the 32P or 33P phosphine oxide ligand for the TRP-M8 receptor confers selectivity and specificity in delivering lethal radiation to the diseased cells.

Abstract: The present invention relates to a process for preparing compounds of the formula (I), 1

Abstract: Compounds of the formula I Ar is a group or unsubstituted or substituted cyclopentyl, cyclohexyl, naphthyl, biphenylyl or an O-, S- or N-containing 5- or 6-membered heterocyclic ring; R1 and R2 are C1-C20alkyl, OR11, CF3 or halogen; R3, R4 and R5 are hydrogen, C1-C20alkyl, OR11 or halogen; R6 is unsubstituted or substituted C1-C24alkyl, C2-C24alkyl, which is interrupted by O, S or NR14 and is unsubstituted or substituted; C2-C24alkenyl, uninterrupted or interrupted by O, S or NR14 and unsubstituted or substituted; unsubstituted or substituted C7-C24arylalkyl; C4-C24cycloalkyl, uninterrupted or interrupted by O, S and/or NR14; or C8-C24arylcycloalkyl; R11 is C1-C20alkyl, C3-C8cycloalkyl, phenyl, benzyl or C2-C20alkyl, interrupted by O or S and unsubstituted or substituted; R12 and R13 are hydrogen, C1-C20alkyl, C3-C8cycloalkyl, phenyl, benzyl or C2-C20alkyl, interrupted by O atoms and unsubstituted or substituted; or R12 and R13 together are C3-C5alkylene, uninterrupted or i

Abstract: A method of increasing the fluorous nature of a compound includes the step of reacting the compound with or tagging the compound with at least one of a second compound having the formula: wherein R is an alkyl group or an aryl group, n is 1, 2 or 3 and Rs is a spacer group and Rf is a branched fluorous group. A chemical compound having the general formula: wherein n, Rs and Rf are defined above.

Abstract: The present invention provides a method for the synthesis of an A-ring synthon phosphine oxide used in the preparation of 19-nor vitamin D compounds, and to novel synthetic intermediates formed during the synthesis. The new method prepares the phosphine oxide from (D)-glucose.

Abstract: The invention relates to a process for the making organic aldehyde compounds from an unsaturated compound by hydroformylation and in the presence of a catalyst system comprising a Group VIII metal and a bidentate phosphorus ligand having two trivalent phosphorus atoms bound to salicylanilide groups.

Abstract: The invention concerns a method for preparing &bgr;-phosphorous nitroxide radicals which comprises preparing in a first step an aminophosphonate by reacting a carbonyl compound, a primary amine and a phosphorous compound, then in a second step in oxidizing said aminophosphonate using on-halogenated organic peracids in a two-phase organic water/solvent medium with a buffered aqueous phase with a pH ranging between 5 and 12.

Abstract: The present invention provides an additive which is able to make a non-aqueous-electrolyte secondary cell or a non-aqueous electrolyte electric double layer capacitor which is excellent in low-temperature characteristics, while maintaining a necessary cell properties, and a non-aqueous-electrolyte secondary cell or a non-aqueous electrolyte electric double layer capacitor that contains therein the additive.

Abstract: The invention concerns a resolution method for a racemic mixture of aldehyde of formula (I). The aldehydes of formula I are useful in their enantiomeric form or their racemic form for preparing transition metal complexes useful as catalysts in hydroformylation reactions of olefins.

Abstract: Compounds of the formula: having two double bonds which are activated so that they will take part in a polymerization reaction, the double bonds being sufficiently close together to ensure that cyclopolymerization will preferentially occur. These compounds are used as monomers which preferentially are cyclopolymerized under the influence of ultraviolet or thermal radiation in the production of network polymers, for example coatings or binders.

Abstract: Compounds of the formula I 1

Abstract: Compounds of the formula I 1

Abstract: A light-emitting polymer and its preparation method, the polymer being excellent in electron injection and transport ability as well as hole injection and transport ability in an EL device, the EL device manufactured from the polymer being also emittable in the blue emission region, in which the EL device from an inorganic material is not mostly emittable. The light-emitting polymer of the invention is an alternated copolymer having repeated units (arylenevinylene units) excellent in hole injection and transport ability and repeated units (fluorinated tetraphenyl units) excellent in electron injection and transport ability with alternated order, as shown in formula (II). An EL device manufactured from the light-emitting polymer, a fluorinated tetraphenyl derivative of formula (I), which is used as a monomer to prepare the light-emitting polymer, and their preparation methods.

Abstract: Bisphenol-phosphorus compound complexes represented by the following general formula (1) are disclosed (R1 to R4 represent hydrogen atom or a group that can be a substituent on a benzene ring; L represents —S— group or a —CHR5— group where R5 represents hydrogen atom or an alkyl group; and R6 to R8 represent an alkyl group, an aryl group, a heterocyclic group etc.). The present invention provides reducing agents that can realize thermally processed image recording materials that can provide sufficient image density at a practical reaction temperature (specifically 100-140° C.) and within a practical reaction time (specifically 1-30 seconds), and can sufficiently suppress the coloration of white portions when the materials are stored in a dark place after the development.

Abstract: This invention provides methods and catalyst systems for catalyzing enantioselective oxidation reactions, including cyclization reactions and enantioselective oxidation reactions of secondary alcohols and other similarly reactive organic substrates. Use of the methods and catalyst systems for kinetic resolution of racemic mixtures of secondary alcohols is also described.

Abstract: The present invention relates to fluorine-containing triarylphosphine oxide derivatives and preparing method thereof. Particularly, the present invention relates to both fluorine- and phosphine oxide-containing triarylphosphine oxide derivatives which can be utilized in preparing polyimides having excellent adhesion, fire retardancy and low dielectric constant as well as superior thermal stability and mechanical properties, and preparing method thereof.

Abstract: A subject of the present invention is new 6,6′-bis-(1-phosphanorbornadiene) diphosphines, their preparation process and their use in asymmetrical catalysis. The new diphosphines correspond to general formula (I): in which R1, R2, R3, R4, R5 are as defined in claim 1.

Abstract: The present invention discloses hydrogen bond stabilized surface modifying agents having a fluorinated or semi-fluorinated carbon-containing tail group, an internal moiety capable of intermolecular hydrogen bonding or related acid-base interactions and a head group capable of reacting or interacting with surfaces such as metal, non-metallic, ceramic, other inorganic oxide or organic surfaces. The present invention also discloses cost effective method for making the agents, methods for treating surfaces therewith, the treated surfaces and devices made therefrom.

Abstract: A method of increasing the fluorous nature of a compound includes the step of reacting the compound with or tagging the compound with at least one of a second compound having the formula: 1

Abstract: The invention relates to the preparation of enantiomerically pure bis-diphenylphosphine oxides in a particularly advantageous manner by (1) reacting an aromatic bromine compound with a diphenylphosphinic chloride in a mixture of tetrahydrofuran and an aromatic hydrocarbon to give a diphenylphosphine oxide, which is isolated from a solution in an aromatic hydrocarbon by adding a saturated aliphatic hydrocarbon; (2) metalating the resulting diphenylphosphine oxide in the 6-position and reacting the metalated diphenylphosphine oxide with iodine at temperatures not less than −25° C.

Abstract: Chelating agents (chelants) of the general structure: wherein: n=2-4 X=—CR1R2—, or whereby at least two of X are of formula III Y=COOH, —PO3H2 or o-hydroxyphenyl R1, R2 and R3 are independently H or C1-C8 alkyls m=1, 2 or 3 and most preferably m=1 Z and Z1 are unsubstituted or substituted C C*=C or CH or N Z1, Z2, Z′1, and Z′2 are independently selected from H (or nothing for Z2 and Z′2 if C* is N) and C1-C10 groups that optionally contain one or more N atoms (optionally attached directly to C*), whereby one of the pairs Z/Z1, Z/Z2 and Z1/Z2 and one of the pairs Z′/Z′1, Z′1/Z′2 and Z′/Z′2 may be connected to form substituted or unsubstituted (hetero)(poly)cyclic structures of less than 20 atoms. C* is either part of an aromatic (hetero)(poly)cyclic structure or linked by a double bond to Z or Z2 and/or Z′ or Z′2.

Abstract: One aspect of the present invention relates to optionally substituted halogenated benzyl halides and the like. These compounds are useful as halogenated benzyl ether-based protecting groups for a variety of functional groups. Another aspect of the present invention relates to use of said protecting groups in an orthogonal protecting group strategy for the synthesis of complex molecules that comprise a number of suitable functional groups. Another aspect of the present invention relates to saccharides bearing various arrays of protecting groups of the present invention. Another aspect of the present invention relates to a method of synthesizing an oligosaccharide or glycoconjugate, comprising the steps of: using a saccharide bearing at least one protecting group of the present invention to glycosylate a second molecule to give a product comprising said saccharide; and removing a protecting group of the present invention from said product.

Abstract: The present invention relates to fluorine-containing triarylphosphine oxide derivatives and preparing method thereof. Particularly, the present invention relates to both fluorine- and phosphine oxide-containing triarylphosphine oxide derivatives which can be utilized in preparing polyimides having excellent adhesion, fire retardancy and low dielectric constant as well as superior thermal stability and mechanical properties, and preparing method thereof.

Abstract: Compounds having the formula: are disclosed. M1 and M2 are the same or different and are transition metal atoms or ions; Z2 and Z3, independently, are the atoms necessary to complete a 3-12 membered heterocyclic ring; Z1 is an alkylene or arylene group; Q1 and Q2 are the same or different and are electron withdrawing groups; L1 and L3, taken together, represent —O—CR13—O—; L2 and L4, taken together, represent —O—CR14—O—; and R13 and R14 are the same or different and are selected from the group consisting of alkyl groups and aryl groups or R13 and R14 represent alkylene or arylene groups that are directly or indirectly bonded to one another. Methods for making such compounds are also disclosed, as are intermediates which can be used in their preparation. Also disclosed are methods for carrying out C—H insertion reactions using bis-transition metal catalysts, such as the above compounds.

Abstract: Compounds of the formula I R1 and R2 independently of one another are C1-C20alkyl, OR11, CF3 or halogen; R3, R4 and R5 independently of one another are hydrogen, C1-C20alkyl, OR1 or halogen; R6, R7, R8, R9 and R10 independently of one another are hydrogen, C1-C20alkyl; C2-C20alkyl which is interrupted once or more than once by nonconsecutive O atoms and which is unsubstituted or substituted by OH and/or SH; or R6, R7, R8, R9 and R10 are OR11, SR11, N(R12)(R13), phenyl or halogen; R11 is C1-C20alkyl, C3-C8cycloalkyl, phenyl, benzyl or C2-C20alkyl which is interrupted once or more than once by O or S and which is unsubstituted or substituted by OH and/or SH; R12 and R13 independently of one another are hydrogen, C1-C20alkyl, C3-C8cycloalkyl, phenyl, benzyl or C2-C20alkyl which is interrupted once or more than once by nonconsecutive O atoms and which is unsubstituted or substituted by OH and/or SH; or R12 and R13 together are C3-C5alkylene which can be interrupted by O, S or NR14; R14 is hydrog

Abstract: One aspect of the present invention relates to novel, electron-rich bidentate ligands for transition metals. A second aspect of the present invention relates to the use of catalysts comprising these ligands in transition metal-catalyzed carbon-heteroatom and carbon-carbon bond-forming reactions. The subject methods provide improvements in many features of the transition metal-catalyzed reactions, including the range of suitable substrates, reaction conditions, and efficiency.

Abstract: The invention relates to the preparation of enantiomerically pure bis-diphenylphosphine oxides in a particularly advantageous manner by (1) reacting an aromatic bromine compound with a diphenylphosphinic chloride in a mixture of tetrahydrofuran and an aromatic hydrocarbon to give a diphenylphosphine oxide, which is isolated from a solution in an aromatic hydrocarbon by adding a saturated aliphatic hydrocarbon; (2) metalating the resulting diphenylphosphine oxide in the 6-position and reacting the metalated diphenylphosphine oxide with iodine at temperatures not less than −25° C.

Abstract: The invention relates to triarylphosphine oxide derivatives containing fluorine substituents that are useful as a monomer in preparation of polymers with improved properties such as chemical resistance and electrical insulating property as well as adhesiveness and flame retardancy. The triarylphosphine oxide derivatives containing fluorine substituents are represented by the chemical formula 1: wherein R1 and R2 are independently a fluorine-substituted alkyl group; and X is hydrogen, a nitro group, or an amine group.

Abstract: This invention provides a novel diphosphine compound which is useful as a ligand of catalysts for asymmetric synthesis reactions, particularly asymmetric hydrogenation reaction. Particularly, it provides a diphosphine compound represented by a general formula (1): wherein R1 and R2 each independently represents a cycloalkyl group, an unsubstituted or substituted phenyl group or a five-membered aromatic heterocycle residue.

Abstract: This invention is to develop novel transition metal catalysts for the practical synthesis of important chiral molecules. The invention emphasizes asymmetric catalysis based on chiral bidentate phosphine ligands with cyclic ring structures which could be used to restrict conformational flexibility of the ligands and thus the efficiency of chiral transfer can be enhanced through the ligand rigidity.

Abstract: Photoinitiator combinations comprising

Abstract: A process for the racemization of atropisomeric bis(phosphine oxide) compounds of formula I: in their (S) or (R) or non-racemic form, is useful for preparing optical active bisphosphine ligands, that form optical active complexes with transition metals. Racemization is thermal and carried out in high or low boiling solvent, under normal or elevated pressure at 105 to 3.5×107 Pa. Heating is performed in a system that allows heating up to 400° C. (reactor, autoclave, aluminum block, round-bottom flask with heating/stirring mantle and the like) or by microwave irradiation or in the melt at a temperature from 260 to 400° C.

Abstract: A catalyst for the bisalkoxycarbonylation of olefins comprising a noble metal compound and a phosphine chalcogenide of the following formula (1): wherein each of R1, R2 and R3 is, independently, an alkyl group or an aryl group each of which may have a substituent, and A is a Group 16 element of the Periodic Table; and R1, R2 or R3 may be combined, directly or through a bridging group, with one another where the groups to be combined may be attached either to an identical phosphorus atom or to different phosphorus atoms. Element A includes oxygen, sulfur and selenium atoms. The noble metal compound includes palladium(II) halides and other palladium compounds. The catalyst may further include a copper(I) halide or other copper compound as a co-catalyst. The use of this catalyst can provide the bisalkoxycarbonylation of olefins with efficiency.

Abstract: A process for the manufacture of bisphosphine oxide compounds and bisphosphonates as intermediates for the production of bisphosphine ligands, in which in a single step processa) a phosphine oxide compound is reacted in an organic solvent at -70.degree. C. to 20.degree. C. with 0.5-3 eq. of a lithium or magnesium amide compound,b) 0.5-3 eq. of oxidatively-acting metal salt or metal salt complex are added to the suspension obtained in stage a) in a temperature range of -70.degree. C. to 20.degree. C., with a racemate of a bisphosphine oxide compound being obtained;c) a racemate cleavage is carried out if desired; andd) the bisphosphonates obtained in stage b) or c) are converted into bisphosphine oxides.

Abstract: A chiral phosphorus-based ligand, in single enantiomer form, which is capable of complexing a transition metal atom and of acting as a ligand in asymmetric chemical catalysts, which comprises the partial structureR.sup.1 R.sup.2 P--O--C--X--Y--C--O--PR.sup.1 R.sup.2 (I)wherein each of X and Y is C or a heteroatom; the C--X--Y--C chain forms part of a linearly-fused bicyclic structure; and either R.sup.1 and R.sup.2 are each independently H or an organic group of up to 20 carbon atoms, including alkyl, fluoroalkyl, aryl, alkylaryl, alkoxy, aryloxy, and alkylaryloxy, or PR.sup.1 R.sup.2 is cyclic such that R.sup.1 and R.sup.2 are covalently linked, optionally with additional substituents.