Studies on the parallel synthesis and evaluation of new heterocyclic extractants for the partitioning of minor actinides

Multiple parallel synthesis and evaluation have been combined in order to identify new nitrogen heterocycles for the partitioning of minor actinides(III) such as americium(III) from lanthanides such as europium(Ill). An array of triazine-containing molecules was made using multiple parallel syntheses from diketones and amide hydrazides. An excess of each of the resulting purified reagents was dissolved in 1,1,2,2-tetrachloroethane containing 2-bromodecanoic acid, and equilibrated with an aqueous solution containing the radiotracers Eu-152 and Am-241 in nitric acid ([Eu] + [Am] < 400 nanomol dm(-3)). Gamma counting of the organic and aqueous phases led to the identification of several new reagents for the selective extraction of americium(III). In particular, 6-(2-pyridyl)-2-(5,6-dialkyl-1,2,4-triazaphenyl)pyridines were found to be effective reagents for the separation of americium(III) from europium(III), (SFAm/Eu was ca. 30 in [HNO3] = 0.013 mol/L).

Synthesis and properties of new trinuclear Mo(II) complexes containing imidazole and benzimidazole ferrocene units

The reaction of FcCOC1 (Fc = (C5H5) Fe(C5H4)) with benzimidazole or imidazole in 1: 1 ratio gives the ferrocenyl derivatives FcCO(benzim) (L1) or FcCO(im) (L2), respectively. Two molecules of L1 or L2 can replace two nitrile ligands in [Mo(eta(3)-C3H5)( CO)(2)(CH3CN)(2)Br] or [Mo(eta(3)-C5H5O)(CO)(2)(CH3CN)(2)Br] leading to the new trinuclear complexes [Mo(eta(3)-C3H5)(CO)(2)(L)(2)Br] (C1 for L = L1; C3 for L = L2) and [Mo(eta(3)-C5H5O)(CO)(2)(L)(2)Br] (C-2 for L = L1; C4 for L = L2) with L1 and L2 acting as N-monodentade ligands. L1, L2 and C2 were characterized by X-ray diffraction studies. [Mo(eta(3)-C5H5O)(CO) 2(L1)(2)Br] was shown to be a trinuclear species, with the two L1 molecules occupying one equatorial and one axial position in the coordination sphere of Mo(II). Cyclic voltammetric studies were performed for the two ligands L1 and L2, as well as for their molybdenum complexes, and kinetic and thermodynamic data for the corresponding redox processes obtained. In agreement with the nature of the frontier orbitals obtained from DFT calculations, L1 and L2 exhibit one oxidation process at the Fe(II) center, while C1, C3, and C4 display another oxidation wave at lower potentials, associated with the oxidation of Mo(II). (C) 2007 Elsevier B. V. All rights reserved.

Comparison of new microemulsion prepared "Pt-in-Ceria" catalyst with conventional "Pt-on-Ceria" catalyst for water-gas shift reaction

New "Pt-in-CeO2" catalyst prepared by microemulsion method is shown to give higher activity for a water-gas shift reaction but with no formation of CH4, the side product from hydrogenation of carbon oxides using a hydrogen-rich reformate as compared to conventional "Pt-on-CeO2" catalysts. Detailed characterization by DRIFT analysis and temperature programmed reduction presented in this work clearly suggest the ceria coverage on Pt inhibits the metal from forming a strong CO adsorption.

Synthesis and cytotoxicity studies of new dimethylamino-functionalised and hetero aryl-substituted titanocene anti-cancer drugs

From the carbolithiation of N,N-dimethylamino fulvene (3a) and different ortho-lithiated heterocycles (furan, thiophene and N-methylpyrrole), the corresponding lithium cyclopentadienide intermediate (4a-c) was formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl4 resulting in dimethylamino-functionalised titanocenes 5a-c. When these titanocenes were tested against LLC-PK cells, the IC50 values obtained were of 240, and 28 mu M for titanocenes 5a and 5b, respectively. The most cytotoxic titanocene 5c with an IC50 value of 5.5 mu M is found to be almost as cytotoxic as cis-platin, which showed an IC50 value of 3.3 mu M, when tested on the LLC-PK cell line, and titanocene 5c is approximately 400 times better than titanocene dichloride itself. (c) 2007 Elsevier B.V. All rights reserved.

Synthesis and cytotoxicity studies of new dimethylamino-functionalised and aryl-substituted titanocene anti-cancer agents

From the carbolithiation of 6-N,N-dimethylamino fulvene (3a) and different lithiated aryl species [p-N,N-dimethylanilinyl lithium, p-anisyl lithium and 4-lithio-benzo[1.3]dioxole (2a-c)], the corresponding lithium cyclopentadienide intermediates 4a-c were formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl4 resulting in dimethylamino-functionalised and aryl-substituted titanocenes 5a-c. When these titanocenes were tested against LLC-PK cells, the IC50 values obtained were of 54, 45 and 26 mu M for titanocenes 5a, b and c, respectively. The most cytotoxic titanocene in this paper, 5c is approximately 10 times less cytotoxic than cis-platin, which showed an IC50 value of 3.3 mu M, when tested on the LLC-PK cell line, but approximately 100 times better than titanocene dichloride. (C) 2007 Elsevier Masson SAS. All rights reserved.

Synthesis and cytotoxicity studies of new dimethylamino-functionalised and indolyl-substituted titanocene anti-cancer drugs

From the carbolithiation of 6-N,N-dimethylamino fulvene (3a) and different ortho-lithiated indole derivatives (5-methoxy-N-methylindole, N-methylindole and N,N-dimethylaminomethylindole), the corresponding lithium cyclopentadienide intermediate (4a-c) was formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl4 resulting in dimethylamino-functionalised titanocenes (5a-c). When these titanocenes were tested against LLC-PK cells, the IC50 values obtained were of 37 and 71 mu M for titanocenes 5a and 5b respectively. The most cytotoxic titanocene in this paper, 5c showed an IC50 value of 8.4 mu M is found to be almost as cytotoxic as cis-platin, which showed an IC50 value of 3.3 mu M, when tested on the LLC-PK cell line, and titanocene 5c is approximately 250 times better than titanocene dichloride itself.

Development of new methodologies for entry to targets of therapeutic interest

This Account provides an overview of strategies that have been reported from our laboratories for the synthesis of targets of therapeutic interest, namely carbohydrates, and prodrugs for the treatment of melanoma. These programmes have involved the development of new synthetic methodologies including the regio- and stereoselective synthesis of specific carbohydrate isomers, and new protecting group methodologies. This review provides an insight into the progress of these research themes, and suggests some applications for the targets that are currently being explored.

Private investment in the countryside: an assessment of the role of new houses and estates in sustaining the rural economy and environment

The British countryside has been shaped and sustained over the years by the establishment of landed estates. Some of our best known, and now most protected, landmarks derive from this tradition by which money, that was often sourced from outside the rural economy, was invested in land. Whilst there was some reversal in this trend during the last century, there is again a widespread desire among people of means to invest in new country property. Paragraph 3.21 of Planning Policy Guidance Note 7: The Countryside - Environmental Quality and Economic and Social Development was introduced in 1997 as a means of perpetuating the historic tradition of innovation in the countryside through the construction of fine individual houses in landscaped grounds. That it was considered necessary to use a special provision of this kind reflects the prevailing presumption of planning authorities against allowing private residential development in open countryside. The Government is currently reviewing rural planning policy and is focusing on higher density housing, affordable homes and the use of brownfield sites. There is an underlying conception that individual private house developments contribute nothing and are seen as the least attractive option for most development sites. The purpose of paragraph 3.21 lies outside the government’s priorities and its particular provisions may therefore be excluded in forthcoming ‘policy statements’. This paper seeks to examine the role of private investors wishing to build new houses in the countryside, and the impact that that might have on local economies. It explores the interpretation placed on PPG7 through an investigation of appeal sites, and concludes by making recommendations for the review process, including the retention of some form of exceptions policy for new build houses.

Synthesis of new phosphino amino alcohol ligands via ortho-alkyllithiation reactions. Versatile coordination behavior toward copper(I) and palladium(II)

2-[Methyl(2-methylphenyl)amino]ethanol undergoes an ortho-alkyllithiation reaction with n-butyllithium to lead to a new mixed benzyllithium−lithium alkoxide. This organolithium species reacts with PPh2Cl, with selective P−C bond formation, to afford the ligand 2-[methyl(2-((diphenylphosphino)methyl)phenyl)amino]ethanol L1. The coordination of the ligand L1 to copper(I) leads to the complex [Cu(L1)2](BF4), whose structure has been determined by an X-ray diffraction study. In the solid state, one of the ligands acts as a monodentate phosphine while the other adopts a tridentate P,N,O coordination mode. A variable-temperature 31P NMR study demonstrated the existence of an equilibrium between the two modes in solution, with a coalescence temperature of ca. 0 °C, indicating a double-hemilabile behavior for the nitrogen and the oxygen functions. L1 reacts with [Pd(Me)(Cl)(COD)] to give a dinuclear complex in which the ligand appears to behave as a bridging anionic P,O ligand. Such a complex could serve as a model for a key intermediate in the proposed mechanism for the homogeneous catalysis of the methoxycarbonylation of propyne by certain palladium(II) complexes containing P,N ligands. L1 can undergo a second ortho-alkylmetalation reaction with n-butyllithium which, after addition of PPh2Cl, provides the new ligand 2-{methyl[2-(bis(diphenylphosphino)methyl)phenyl]amino}ethanol (L2) in high yield.

The role of self-teaching in learning orthographic and semantic aspects of new words

This study explores how children learn the meaning (semantics) and spelling patterns (orthography) of novel words encountered in story context. English-speaking children (N = 88) aged 7 to 8 years read 8 stories and each story contained 1 novel word repeated 4 times. Semantic cues were provided by the story context such that children could infer the meaning of the word (specific context) or the category that the word belonged to (general context). Following story reading, posttests indicated that children showed reliable semantic and orthographic learning. Decoding was the strongest predictor of orthographic learning, indicating that self-teaching via phonological recoding was important for this aspect of word learning. In contrast, oral vocabulary emerged as the strongest predictor of semantic learning.

Climate change and the emergence of new organizational landscapes

There is general agreement across the world that human-made climate change is a serious global problem,although there are still some sceptics who challenge this view. Research in organization studies on the topic is relatively new. Much of this research, however, is instrumental and managerialist in its focus on ‘win-win’ opportunities for business or its treatment of climate change as just another corporate social responsibility (CSR) exercise. In this paper, we suggest that climate change is not just an environmental problem requiring technical and managerial solutions; it is a political issue where a variety of organizations – state agencies, firms, industry associations, NGOs and multilateral organizations – engage in contestation as well as collaboration over the issue. We discuss the strategic, institutional and political economy dimensions of climate change and develop a socioeconomic regimes approach as a synthesis of these different theoretical perspectives. Given the urgency of the problem and the need for a rapid transition to a low-carbon economy, there is a pressing need for organization scholars to develop a better understanding of apathy and inertia in the face of the current crisis and to identify paths toward transformative change. The seven papers in this special issue address these areas of research and examine strategies, discourses, identities and practices in relation to climate change at multiple levels.