Synthesis, characterization, spectral and catalytic activity of tetradentate (NNNO) azo-imine Schiff base copper(II) complexes

The hexadentate ligand, 2,2′-bis(salicylideneamino)azobenzene, 1 has been synthesized from 2,2′-diaminoazobenzene and salicylaldehyde in refluxing diethyl ether. Reaction of ligand 1 with Cu(II) acetate and Cu(II) perchlorate separately in methanol afforded tetradentate (N,N,N,O) Cu(II) complexes, Cu(L) & [Cu(HL)]ClO4 respectively [where H2L represent the one imine moiety cleavage product of ligand 1 (H represents the dissociable amino and phenolic protons)]. These were characterized by microanalytical data and spectroscopic studies. In addition, the crystal structures of the ligand 1 and complexes Cu(L) & [Cu(HL)]ClO4 were determined by X-ray diffraction analysis. The diffraction analysis revealed that the ligand (H2L) binds Cu(II) centers in (N,N,N,O) tetra dentate fashion in distorted square planer geometry. In complex [Cu(HL)]ClO4 the apical position of copper center is weakly coordinated with one perchlorate ion. The dimeric structure of the molecule [Cu(HL)]ClO4 is stabilized through NH2···O hydrogen bonds. The fluorescence and redox property of ligand 1 and complexes Cu(L) & [Cu(HL)]ClO4 were studied. Preliminary DFT calculations were carried out using crystallographic coordinates to understand the electronic spectra and redox properties of the ligand and complexes. The complex Cu(L) shows very good catalytic activities towards oxidation of benzyl alcohol to benzaldeyhde (under solvent-free condition) and organic thioethers to sulfoxide and sulfones using H2O2 as the oxidant.publishe

Plano de negócio de uma empresa de aquisição e recuperação de créditos

JEL Classification System: M1 Business Administration, M13 StartupO presente trabalho constitui um Plano de Negócio cuja finalidade é apurar a viabilidade económica e financeira de uma empresa a criar, a qual desenvolverá o seu negócio através da aquisição e recuperação de créditos de cobrança duvidosa provenientes do sistema bancário português. A metodologia percorreu as fases inerentes à elaboração de um Plano de Negócio. Assim, iniciou-se o trabalho por uma análise da envolvente externa à empresa. Prosseguiu com a apreciação da estrutura, valores e recursos de que internamente poderíamos dispor. Após aquelas apreciações, determinámos os factores estratégicos do negócio e efectuámos uma análise SWOT que nos permitiu, definida a nossa missão e objectivos, estabelecer as estratégias e políticas. A implementação das estratégias foi a fase seguinte. Para tal foram elaborados programas, orçamentos e definidos procedimentos. Terminámos o Plano de Negócio com a avaliação da performance resultante da exploração prevista. Chegámos à conclusão que, para além de 2,5% do crédito concedido pelo sistema bancário português estar em incumprimento (M€ 7.140), temos um mercado em crescimento. Na realidade, a banca evidencia um volume M€ 3.500 de novos créditos vencidos em cada ano. Pretendem as instituições de crédito melhorar a sua rentabilidade e solvabilidade externalizando a cobrança de aproximadamente M€ 1.400/ano desse crédito vencido, designado abreviadamente por NPL (Non Performing Loans), através da sua venda. O mercado está dominado em 80% por um player. Teremos competências, dotar-nos-emos de fundos e assumiremos um ponto crítico de vendas baixo, factores que nos permitirão iniciar a actividade com a compra de k€ 9.000 de NPL ao valor nominal e triplicar essa cifra ao fim de 10 anos obtendo uma TIR de 32% e um Discounted Payback Period de 7 anos.The present work constitutes a Business Plan whose purpose is to verify the economic and financial viability to create a company, which will develop its business through the acquisition and recovery of non performing loans proceeding from the Portuguese Banking System. The methodology covered the inherent phases to the elaboration of a Business Plan. Thus, the work was initiated by the environmental scanning analysis of the company. It continued with the appreciation of the structure, culture and resources that internally we could make use. After those appreciations, we determined the strategic factors and made a SWOT analysis, which allowed us, once defined our mission and objectives, to establish the strategies and policies. The next step was the implementation of the strategies. In order to that, programs and budgets has been elaborated and procedures defined. We finished the Business Plan by the evaluation of the performance. We concluded that, beyond 2,5% of the credit made by the Portuguese Banking System are non performing (M€ 7.140), there’s a growing market. In fact, the Banking System evidences an annual volume of M€ 3.500 of news non performing loans. The Financial Institutions intent to improve its profitability and liquidity ratios outsourcing the collection of approximately M€ 1.400/year, through the sell of this non performing loans. The market is dominated by a player with a market-share of 80%. We will have skills, equity and a low break even point, that will allow us to initiate the activity with the purchase of k€ 9.000 of NPL nominal value, and to triple this number in ten years getting an IRR of 32% and a Discounted Payback Period of 7 years

Selective potassium chloride recognition, sensing, extraction, and transport using a chalcogen-bonding heteroditopic receptor

Chalcogen bonding (ChB) is rapidly rising to prominence in supramolecular chemistry as a powerful sigma (σ)-hole-based noncovalent interaction, especially for applications in the field of molecular recognition. Recent studies have demonstrated ChB donor strength and potency to be remarkably sensitive to local electronic environments, including redox-switchable on/off anion binding and sensing capability. Influencing the unique electronic and geometric environment sensitivity of ChB interactions through simultaneous cobound metal cation recognition, herein, we present the first potassium chloride-selective heteroditopic ion-pair receptor. The direct conjugation of benzo-15-crown-5 ether (B15C5) appendages to Te centers in a bis-tellurotriazole framework facilitates alkali metal halide (MX) ion-pair binding through the formation of a cofacial intramolecular bis-B15C5 M+ (M+ = K+, Rb+, Cs+) sandwich complex and bidentate ChB···X- formation. Extensive quantitative 1H NMR ion-pair affinity titration experiments, solid-liquid and liquid-liquid extraction, and U-tube transport studies all demonstrate unprecedented KCl selectivity over all other group 1 metal chlorides. It is demonstrated that the origin of the receptor's ion-pair binding cooperativity and KCl selectivity arises from an electronic polarization of the ChB donors induced by the cobound alkali metal cation. Importantly, the magnitude of this switch on Te-centered electrophilicity, and therefore anion-binding affinity, is shown to correlate with the inherent Lewis acidity of the alkali metal cation. Extensive computational DFT investigations corroborated the experimental alkali metal cation-anion ion-pair binding observations for halides and oxoanions.publishe

Hydrosulfide (HS⁻) recognition and sensing in water by halogen bonding hosts

Hydrogen sulfide (H₂S) plays a crucial signalling role in a variety of physiological systems, existing as the hydrosulfide anion (HS⁻) at physiological pH. Combining the potency of halogen bonding (XB) for anion recognition in water with coumarin fluorophore incorporation in acyclic host structural design, the first XB receptors to bind and, more importantly, sense the hydrosulfide anion in pure water in a reversible chemosensing fashion are demonstrated. The XB receptors exhibit characteristic selective quenching of fluorescence upon binding to HS⁻. Computational DFT and molecular dynamics simulations in water corroborate the experimental anion binding observations, revealing the mode and nature of HS⁻ recognition by the XB receptors.publishe

Internacionalização do ensino superior: para além da mobilidade internacional

A internacionalização não pode ser implementada na ausência do entendimento sobre as mudanças permanentes a que o mundo global está hoje sujeito e o seu propósito deve ser a melhoria da qualidade e dar um contributo significativo para a sociedade. Mesmo na presença de um número considerável de estratégias internacionais, nacionais, regionais e locais que dinamizam a internacionalização através da mobilidade, o número de estudantes em mobilidade internacional na área da OCDE em 2015 representa cerca de 5,6% das matrículas a nível mundial, valor que demonstra que a maioria dos estudantes são-no no seu país de origem. O padrão de mobilidade concentra-se num pequeno conjunto de países, moldado por fatores de proximidade, e os maiores países anfitriões são as economias avançadas de língua inglesa. Proporcionar excelentes oportunidades de mobilidade é fundamental, mas além de oferecer oportunidades para a pequena proporção de estudantes que pode estudar fora, a instituição deve esforçar-se para oferecer, a todos, as competências necessárias para obter sucesso no mundo global. O objetivo desta comunicação é discutir o conceito de internacionalização at-home e a criação de uma cultura promotora da compreensão internacional ou intercultural que não implique necessariamente o envolvimento em programas de mobilidade ou outras atividades além-fronteiras.info:eu-repo/semantics/publishedVersio

Cysteine allows ovarian cancer cells to adapt to hypoxia and to escape from carboplatin cytotoxicity

The authors would like to acknowledge the Instituto Portugues de Oncologia de Lisboa Francisco Gentil (IPOLFG) for partially funding the project. We would also like to acknowledge Dr Dialina Brilhante and Dr. Teresa Guerreiro (Servico de Imuno-hemoterapia, IPOLFG) for providing blood donors samples; to Dr Humberto Goncalves (Pharmacy, IPOLFG) for paclitaxel and carboplatin preparation, and Marta Teixeira (IBET) for the technical support in 3D models. The study was also funded by Projecto TVI. This research was supported by Fundacao para a Ciencia e Tecnologia (FCT) (PhD ProRegeM program, PD/BD/105893/2014, FCT fellowship, PD/BD/105768/2014). iNOVA4Health - UID/Multi/04462/2013, a program financially supported by Fundacao para a Ciencia e Tecnologia/Ministerio da Educacao e Ciencia, through national funds and co-funded by FEDER under the PT2020 Partnership Agreement is acknowledged.Ovarian cancer is the second most common gynaecologic malignancy and the main cause of death from gynaecologic cancer, due to late diagnosis and chemoresistance. Studies have reported the role of cysteine in cancer, by contributing for hydrogen sulphide (H2S) generation and as a precursor of glutathione (GSH). However, the role of cysteine in the adaptation to hypoxia and therapy response remains unclear. We used several ovarian cancer cell lines, ES2, OVCAR3, OVCAR8, A2780 and A2780cisR, to clarify cysteine relevance in ovarian cancer cells survival upon hypoxia and carboplatin. Results show that ES2 and OVCAR8 cells presented a stronger dependence on cysteine availability upon hypoxia and carboplatin exposure than OVCAR3 cells. Interestingly, the A2780 cisR, but not A2780 parental cells, benefits from cysteine upon carboplatin exposure, showing that cysteine is crucial for chemoresistance. Moreover, GSH degradation and subsequent cysteine recycling pathway is associated with ovarian cancer as seen in peripheral blood serum from patients. Higher levels of total free cysteine (Cys) and homocysteine (HCys) were found in ovarian cancer patients in comparison with benign tumours and lower levels of GSH were found in ovarian neoplasms patients in comparison with healthy individuals. Importantly, the total and S-Homocysteinylated levels distinguished blood donors from patients with neoplasms as well as patients with benign from patients with malignant tumours. The levels of S-cysteinylated proteins distinguish blood donors from patients with neoplasms and the free levels of Cys in serum distinguish blood from patients with benign tumours from patients with malignant tumours. Herein we disclosed that cysteine contributes for a worse disease prognosis, allowing faster adaptation to hypoxia and protecting cells from carboplatin. The measurement of serum cysteine levels can be an effective tool for early diagnosis, for outcome prediction and follow up of disease progression.publishersversionpublishe

Acylthioureas as anion transporters: the effect of intramolecular hydrogen bonding

Small molecule synthetic anion transporters may have potential application as therapeutic agents for the treatment of diseases including cystic fibrosis and cancer. Understanding the factors that can dictate the anion transport activity of such transporters is a crucial step towards their application in biological systems. In this study a series of acylthiourea anion transporters were synthesised and their anion binding and transport properties in POPC bilayers have been investigated. The transport activity of these receptors is dominated by their lipophilicity, which is in turn dependent on both substituent effects and the formation and strength of an intramolecular hydrogen bond as inferred from DFT calculations. This is in contrast to simpler thiourea systems, in which the lipophilicity depends predominantly on substituent effects alone

Fluorinated synthetic anion carriers:experimental and computational insights into transmembrane chloride transport

A series of fluorinated tripodal tris-thioureas function as highly active anion transporters across lipid bilayers and cell membranes. Here, we investigate their mechanism of action using anion transport assays in cells and synthetic vesicles and molecular modelling of transporter–lipid interactions. When compared with non-fluorinated analogues, fluorinated compounds demonstrate a different mechanism of membrane transport because the free transporter cannot effectively diffuse through the membrane. As a result, in H+/Cl cotransport assays, fluorinated transporters require the presence of oleic acid to form anionic oleate complexes for recycling of the transporter, whereas non-fluorinated analogues readily diffuse through the membrane as free transporters and show synergistic transport with the proton transporter gramicidin. Molecular dynamics simulations revealed markedly stronger transporter–lipid interactions for fluorinated compounds compared with non-fluorinated analogues and hence, higher energy barriers for fluorinated compounds to cross the membrane as free transporters. With use of appropriate proton transporters to ensure measurement of the correct rate-limiting steps, the transport rates determined in synthetic vesicle assays show excellent agreement with the anion transport rates determined in cell- based assays. We conclude that integration of computational and experimental methods provides a strategy to optimise transmembrane anion transporter design for biomedical applications.ARC, EPSRC, FCT, CICEC