An optimised synthesis of 2-[2,3-Bis(tert-butoxycarbonyl)guanidino]ethylamine

This short report describes an improved, reliable, and high-yielding (>90%) synthesis of 2-[2,3-bis(tert-butoxycarbonyl)guanidino]ethylamine. The method is scalable (>5 g), and the product obtained directly from the reaction mixture requires no further purification. In addition, this methodology can be successfully applied to other diamine substrates (1,3-propyl and 1,4-butyl; 70% and 61% yield, respectively).

Examples of regioselective anion recognition among a family of two-, three-, and four-"armed" bis-, tris-, and tetrakis(thioureido) [n]polynorbornane hosts

A family of conformationally preorganized, [n]polynorbornane-based anion hosts 1a,b–6a,b have been synthesized. The series includes receptors with 4, 8, and 12 H-bond donors. Using ¹H NMR titration techniques, evaluation of the new hosts against a series of alkyl and aryl dicarboxylates as well as a range of phosphoanionic species has revealed that the tris(thioureido) hosts (in particular 3a) are capable of regioselectively binding dicarboxylates and pyrophosphate (H₂PPi^2–).

Conversion coatings of Mg-alloy AZ91D using trihexyl(tetradecyl) phosphonium bis(trifluoromethanesulfonyl)amide ionic liquid

This work reveals the performance of a trihexyl(tetradecyl)phosphonium bis(trifluoromethanesulfonyl)amide ([P6,6,6,14][NTf2]) ionic liquid (IL) conversion coating upon AZ91D. Such conversion coatings represent a novel avenue for chromate replacement. An optimization of coating performance was pursued by careful alloy pretreatment to generate a surface on which the coating performs best, as the AZ91 substrate is distinctly different from pure or dilute Mg alloys. The results reveal that a functional conversion coating can be achieved, retarding anodic dissolution kinetics, causing a significant decrease in corrosion rate. The coating efficacy is closely tied to the pretreatment performed, which dictates both the microstructural and electrochemical heterogeneity of the surface. The resulting coatings were found to contain MgxFx and phosphonium cation related components, the proportions of which were dependent on the pretreatment.

Bis-thiourea macrocycles incorporating fused [n]polynorbornanes: binding of flexible versus rigid dicarboxylates

Two macrocyclic bis-thiourea hosts 5 and 6 were constructed and their interactions with two dicarboxylates of similar size (pimelate = flexible and terephthalate = rigid) were evaluated using 1H NMR titration techniques. In contrast to previous work with thiourea functionalised [n]polynorbornanes (where a notable increase in H:G affinity was noted for the rigid guest), the new macrocyclic hosts, in particular host 6, bind pimelate more strongly than terephthalate (for 6 binding pimelate log Ka = 4.7, terephthalate log Ka = 3.7). A binding arrangement in which the flexible dicarboxylate is ‘perched’ above the macrocycle is proposed to justify these results.

Physicochemical properties of N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide for sodium metal battery applications.

The physicochemical properties of a range of NaNTf2 (or NaTFSI) salt concentrations in N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (or C3mpyrFSI) ionic liquid were investigated by DSC, conductivity, cyclic voltammetry and diffusivity studies. Cyclic voltammetry indicated a stable sodium plating behavior with a current of 5 mA cm(-2) at 25 °C to 20 mA cm(-2) at 100 °C, along with high reversibility identifying this electrolyte as a possible candidate for sodium-ion or sodium metal battery applications. (23)Na NMR chemical shifts and spectral linewidths (FWHM) indicate a complex coordination of the Na(+) ion which is dependent on both temperature and salt concentration with an apparently stronger coordination to the NTf2 anion upon increasing the NaNTf2 concentration. Temperature dependent PFG-NMR diffusion measurements show that both FSI and NTf2 have a comparable behaviour although the smaller FSI anion is more diffusive.

Modular synthesis of linear Bis- and Tris-monodentate fused [6]Polynorbornane-Based Ligands and their assembly into coordination cages

A modular approach has been developed for the synthesis of rigid linear di- and tritopic ligands based on a fused [6]polynorbornane scaffold. The design provides up to three sites for installing functionality, including both "ends" and a "central" position with the advantage that each region can be independently addressed during synthesis. To illustrate the utility of the approach, both pyridyl and picolyl units were incorporated to provide six new ligands, with centers and ends either matched or mismatched. Indeed, both [M2 L4 ] cages with endohedral functionality and [M3 L4 ] complexes were cleanly produced from these ligands with assembled structures confirmed by using (1) H NMR spectroscopy, HRMS, and molecular modelling.

Physical properties of high Li-ion content N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide based ionic liquid electrolytes

Electrolytes based on bis(fluorosulfonyl)imide (FSI) with a range of LiFSI salt concentrations were characterized using physical property measurements, as well as NMR, FT-IR and Raman spectroscopy. Different from the behavior at lower concentrations, the FSI electrolyte containing 1 : 1 salt to IL mole ratio showed less deviation from the KCl line in the Walden plot, suggesting greater ionic dissociation. Diffusion measurements show higher mobility of lithium ions compared to the other ions, which suggests that the partial conductivity of Li(+) is higher at this higher composition. Changes in the FT-IR and Raman peaks indicate that the cis-FSI conformation is preferred with increasing Li salt concentration.

Complexos derivados de 1,1-bis(difenilfosfina)ferroceno : sintese, caracterizacao e propriedades cataliticas

Uma parte importante da química de orgametálicos atual centra-se no estudo de compostos heterobimetálicos com o propósito de avaliar de que modo as possíveis interações entre os metais podem alterar a reatividade dos centros metálicos presentes na molécula. Os ligantes ferrocenilas tem sido bastante utilizados para obter-se compostos desta natureza. Dentro desta classe de ligantes destaca-se o 1,1'-bis(difenilfosfina)ferroceno(dppf). Muitos trabalhos surgiram na literatura nos últimos dez anos descrevendo a síntese, caracterização estrutural, no estado sólido ou em solução, de novos complexos metálicos derivados deste metaloligante, bem como o estudo de suas propriedades catalíticas. O objetivo deste trabalho foi sintetizar novos compostos derivados do 1,1'-bis(difenilfosfina) ferroceno (dppf) e estudá-los no estado sólido ou em solução. Desta forma, foram pela primeira vez sintetizados os compostos dppfFe(NO)2(1), [dppfCo(NO)2][SBf6](2) e dppfNicod(3) e [dppfNi(MeCN)4]2 (4) os quais foram caracterizados por espectroscopia na região do infravermelho, ressonância magnética nuclear de ¹H e ³¹P{¹H}, análise elementar de C,H e N, condutividade molar no caso do composto catiônico(2) e difração de Raios-X de monocristal, no caso do composto(1). A espectroscopia Mössbauer de 57Fe constitui-se uma técnica adequada para a análise deste metaligante, que contém um átomo de Fe na sua molécula, pois pode fornecer informações estruturais e evidenciar eventuais efeitos interativos que ocorram entre os centros metálicos quando o ligante encontra-se complexado a outros metais. Foram, então, estudados por espectroscopia Mössbauer, à baixa temperatura, os compostos (1),(2),(3),(4) e dppfFe(CO)3 (5) e os resultados obtidos comparados com os apresentados na literatura para compostos análogos contendo o ligante dppf. Os complexos derivados do dppf exibem um processo de oxidação centrado no ferroceno além dos processos de oxiredução presentes nos outros centros metálicos da molécula. O estudo das alterações que podem ocorrer neste processo devido à presença de um segundo metal de transição ou dos ligantes é importante pois pode fornecer informações sobre como modular o potencial redox centrado no ligante ferrocenila, permitindo assim um controle de sua reatividade. Sendo assim, neste trabalho foi realizado um estudo eletroquímico, por voltametria cíclica, dos compostos (1),(2) e (5). Compostos de Ni(0) ou Ni(II) são conhecidos catalisadores em reações de oligomerização e polimerização de olefinas e dienos. Compostos ferrodinitrosilas e cobaltodinitrosilas, na presença de redutores, apresentam alta seletividade em reações de ciclomerização de dienos. Nestes sistemas catalíticos a atividade e seletividade doscompostos está intimamente relacionada com a natureza dos ligantes unidos ao metal de transição do percussor catalítico. Devido às características dos compostos sintetizados e estudados neste trabalho, decidiu-se verificar a possível influência do ligante ddpf, na atividade e seletividade das reações com dienos, escolhendo-se o butadieno como substrato modelo. Estudou-se, então, a atividade catalítica dos compostos (1),(2),(3),(4),(5) e dppfNiCl2 (6) frente ao butadieno, na ausência e presença do cocatalisador, AlEt2Cl.

Ne bis in idem: limites jurídico-constitucionais à persecução penal

This legal research aims to demonstrate the prohibition in the Brazilian criminal system of a multiple imputation for the same fact in a simultaneous or successive way. For that it is developed a different idea of the subject. Through comparative, eletronic and bibliographical researches, the dissertation was accomplished in a way to establish the content of the foundations of the criminal procedural emphasizing as fundamental premise the values of the Constitution. In the first section it was demonstrated the limits of the theme and the objective of the research. After that, it was analyzed the basic function of the criminal suit which has the important mission of limiting state's punitive power. In the same way, the criminal procedure corresponds to a warranty of the citizens' freedom. In the same section, it is shown how it is possible to abandon the myth of the real truth in the criminal law system. In the third section of the research, there were pointed elements and definitions about the cognition object, specially the litigious object or "thema decidendum", and also the peculiarities of the judged cases. In the fourth section the subject about origins and evolution of the criminal procedure and its objectives in the legal system is developed to demonstrate its perspectives. Some aspects of the identity's concept of the presupposition of the facts are as well demonstrated in order to relate the theme to the prohibition of multiple imputation. There are also considerations about some other important aspects as the incidence of the legal rules and the possible change on the elements of the penal type. There are several comments about legal procedural in other legal systems comparing them to Brazilian's most elevated Courts. In the end it was systematized the limits to criminal imputation, emphasizing the defende's right as a foundation of the legal system. Is was registered that the ius persequendi can be exercised once