The reactions of trivalent phosphorus esters, including trialkyl phosphites, dialkyl phosphonites, and alkyl phosphinites, with 3-halo- and 3,4-dihalo-furan-2,5-diones has been shown to lead to the formation of novel phosphorus ylides possessing additional phosphoryl-containing groups. For the reaction of 3,4-dihalo-furan-2,5-diones with trialkyl phosphites, the products are trialkoxyphosphonium ylides containing an adjacent geminal bisphosphonate unit. These can be used to provide a convenient route to novel 2,3,3-tris(dialkoxyphosphoryl)-substituted propionate esters which can be hydrolyzed to give the corresponding novel trisphosphonic monocarboxylic acid.

We have previously reported that 3-halogenated pyrrole-2,5-diones 1 (Z = NR) react with trialkyl phosphites, dialkyl phosphonites and alkyl phosphinites to give the corresponding ylides 2 and hence the bisphosphoryl systems 3. Similarly, the dihalogenated heterocycles 4 (Z = NR) give rise to the ylides 5 and hence the trisphosphoryl systems 6. We have also shown that analogous reactions occur with the corresponding furan systems 1 and 4 (Z = O).

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A convenient route to isoindolo[2,1-a]indol-6-ones has been developed starting from the appropriate 2-(N-phthaloyl)benzoic acids. Formation of the acid chlorides with thionyl chloride followed by heating with triethyl phosphite in a suitable solvent resulted in a multistep reaction giving tetracyclic β-ketophosphonates that on reduction with sodium borohydride gave the required indolones in good overall yields. Analogous β-ketophosphonates were also prepared starting with N,N-(1,8-naphthaloyl)-2-aminobenzoic acid and 2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)benzoic acids although of these only the naphthaloyl product could be reduced with sodium borohydride without cleaving the amide bond in the ring system.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The complexes formed from the reaction of N-acylated tris-(pyridin-2-yl)methylamine (LH) with [Re(CO)(5)Br] depend on the structure of the ligand and the reaction conditions. Thus, while N-[1,1,1-tris-(pyridin-2-yl)methyl]acetamide coordinates through the three pyridine nitrogens to give a stable cationic complex [LHRe(CO)(3)Br], the analogous N-benzoyl ligand reacts under similar conditions to give a neutral complex [LRe(CO)(3)] with coordination through two pyridine nitrogens and a deprotonated amide. To try to explain these different outcomes, the reactions of some structurally related N-acylated [1,1-bis(pyridin-2-yl)]methylamines (L'H) with [Re(CO)(5)Br] have been studied and the reaction pathways identified. These studies indicate that a neutral complex [L'HRe(CO)(3)Br] is initially formed in which the amide portion of the ligand is uncoordinated, but that this complex under appropriate conditions then rearranges to give a cationic complex [L'HRe(CO)(3)]Br in which the coordinated amide nitrogen either remains protonated or is present in its imidic acid tautomeric form. Elimination of HBr from these complexes either thermally or in the presence of base then gives stable neutral complexes [L'Re(CO)(3)]. The impact of the N-acyl group and any substituent at the apex of the tripodal ligands (L''H) on the relative stabilities of intermediate complexes on the reaction pathway helps provide an explanation for the observed difference in behaviour of the N-acylated tris(pyridin-2-yl)methylamines (LH).

The reaction of N-benzoyl and N-acetyl tris(pyridin-2-yl) methylamine 1b and 1c (LH = tpmbaH and tpmaaH) with [Re(CO)(5)Br] has been investigated and shown to proceed via the initial formation of a cationic rheniumtricarbonyl complex [(LH)Re(CO)(3)]Br in which coordination of the ligand occurs via the three pyridine rings. For tpmbaH 1b, but not tpmaaH 1c, this initial complex 2b readily undergoes the loss of HBr to give a neutral octahedral complex 4b [(L)Re(CO)(3)] where coordination occurs via two of the pyridine rings and the deprotonated amide nitrogen. The H-1 NMR spectrum of the latter complex 4b is very unusual in that at room temperature the signals for the 3-H protons on the coordinated pyridine rings are not visible due to extreme broadening of these resonances. Comparison with the analogous complex 7 from N-benzoyl bis(pyridin-2-yl) methylamine 6b (bpmbaH) confirms that this is due to rotation of the uncoordinated pyridine ring. The structure of the cationic complex 3d [(LH)Re(CO)(3)]Br formed from N-benzyl tris(pyridin-2-yl) methylamine 1d (bz-tpmaH) is also discussed. The crystal structures of complexes [(tpmba)Re(CO)(3)] 4b, [(bz-tpmaH)Re(CO)(3)]Br 3d and [(bpmba)Re(CO)(3)] 7 have been determined. In all complexes the coordination geometry around Re is distorted octahedral with a fac{Re(CO)(3)}(+) core. (C) 2009 Elsevier B.V. All rights reserved.

Dialkyl heteroaroylphosphonates based on thiophene, pyrrole or furan have been prepared and their reactions with trimethyl phosphite investigated. Deoxygenation of the carbonyl groups in these heteroaroylphosphonates occurs to give carbene intermediates, which then undergo further reaction. In the case of the furan-3-oylphosphonates and those systems containing a thiophene or pyrrole ring, the major reaction pathway involves intermolecular trapping of the carbene intermediates by the trimethyl phosphite, leading to the formation of ylidic phosphonates that can be readily converted into the corresponding 1,1-bisphosphonates. However, in some furan-2-oylphosphonates the carbenes generated undergo ring-opening to initially give acyclic alkynylphosphonates which may react further to give other novel phosphorus compounds. The effects of substituents on the extent to which intermolecular trapping of the initially formed carbene competes with intramolecular rearrangement has been investigated. The latter process appears to be suppressed by a substituent at the 5-position of the furan ring, the resulting ylidic phosphonates being a rare example of an efficient intermolecular trapping of a furan-2-yl carbene.

Polydentate ligands containing the bis(hydroxymethyl)phosphine unit have been reported to exhibit enhanced oxidative stability, which would make them attractive for use in Tc-99m-radiopharmaceutical imaging agents. Benzylethyl(hydroxymethyl)phosphine, benzylbis(hydroxymethyl)phosphine and benzyldiethylphosphine were prepared in order to investigate the origin of this oxidative stability. Little evidence was found to indicate that the hydroxymethylphosphines show an enhanced level of stability, but it was demonstrated that the reaction conditions employed in their preparation generated a number of closely related by-products, which are likely to limit the usefulness of the hydroxymethylphosphines in commercial radiopharmaceutical applications.

Dimethyl 2-acetoxy- and dimethyl 2-benzoyloxy-benzoylphosphonate undergo cyclisation and deoxygenation in the presence of excess trimethyl phosphite to give dimethyl (3-methyl-1-benzofuran-2-yl)phosphonate and dimethyl (3-phenyl-1-benzofuran-2-yl)phosphonate, respectively. The reaction pathway has been shown to involve phosphite attack on initially formed tricyclic dioxaphospholane intermediates with the subsequent loss of two molecules of trimethyl phosphate. In the absence of additional trimethyl phosphite the initially formed tricyclic dioxaphospholane intermediates lose one molecule of trimethyl phosphate and then undergo a novel rearrangement to give β-ketophosphonates. The mechanism for this reaction helps explain some previously reported epoxide rearrangements. In contrast, the initially formed anionic intermediate from the reaction of dimethyl 2-benzoyloxymethylbenzoylphosphonate with trimethyl phosphite undergoes decomposition to give a carbene intermediate which is trapped by the trimethyl phosphite to give an ylidic phosphonate.

A new route to interfacial bonding between ceramic and matrix in biocomposites is identified. A tailored allyl phosphonic acid is used as a coupling agent bound to the surface of a bioceramic to form a 'grafted' calcium phosphate (CAP). The allyl phosphonic acid coupling agent is synthesised by reaction of allyl halide and trialkyl phosphite. Successful synthesis was confirmed by nuclear magnetic resonance and Fourier transform infrared spectroscopy (FTIR). The allyl phosphonic acid was incorporated onto calcium phosphate using a wet chemical coprecipitation synthesis route. The resulting 'grafted' CAP was characterised using FTIR coupled with photoacoustic sampling, and Fourier transform Raman spectroscopy (FTR). The spectroscopic data suggest an interaction between the allyl phosphonic acid and calcium phosphate resulting from observed reductions in intensity of the hydroxyl (3570 cm(-1)) and phosphate v(3) (1030 cm(-1)) peaks. The continued presence of C=C functionality on the surface of the grafted CAP was indicated by FTIR and FTR spectra (peaks at 1650 and 1635 cm(-1) respectively) and confirmed by X-ray photoelectron spectroscopy (XPS). On the basis of these results, it is concluded that grafted CAP may be used to produce a chemically bonded composite with superior mechanical properties.

The synthesis of a range of new phosphine-containing polydentate ligands has been achieved by addition of sulfur and nitrogen nucleophiles to dimethylvinylphosphine sulfide, followed by reduction of the resulting phosphine sulfides with lithium aluminium hydride.

Copper nitrite complexes of stoichiometric formulae [Cu(NO2)nL] (n=1 or 2), where L is a Schiff base or amide derivative of 1,1,1-tris(2-pyridyl)methylamine, have been prepared and characterized. The crystal structures of the mononuclear Schiff base complex [Cu(NO2)2(tpmbz)] [tpmbz=(C5H4N)3CNCHC6H5], the nitrite-bridged dinuclear Schiff base complex [{Cu(NO2)(tpmsal)}2]·Et2O [tpmsalH=(C5H4N)3CNCHC6H4OH-2] and the polymeric amide complex [{Cu(NO2)(tpms)}n]·nH2O [tpmsH=(C5H4N)3CNHC(O)CH2CH2CO2H] are reported.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.