Synthesis, structure and physical properties of a low dimensional compound

The crystal structure of (µ3-oxo)hexakis(cyanoacetato-¿O, O')(cyanoacetato-¿O)diaquatriiron(III) cyanoacetic acid shows the formation of trinuclear complexes in a hydrogen-bond network that bonds all the molecules in a 3D arrangement. For this complex, within whose clusters the whole magnetic interaction takes place, 57Fe Mössbauer spectroscopy shows that the Fe cations are in the S = 5/2 state in the temperature range 2–295 K. The asymmetric broadening of the absorption peaks below 80 K is consistent with strong antiferromagnetic interactions between the metal spins. The magnetization measurements also show the antiferromagnetic character of the spin ensemble and an ST = 1/2 magnetic ground state typical of triangular systems with similar J between Fe-Fe pairs

A study of the effect of conventional drilling and helical milling in surface quality in titanium Ti-6Al-4V and Ti-6AL-7Nb alloys for medical applications

In the manufacturing of a medical device, may occur the need to make a hole with a specific function. Among current methods, conventional drilling (CD) referred in this work as drilling (D) and helical milling (HM) are two options with different potential. When making the hole, it is important to choose the most suitable method to obtain the desired geometry and ensure the functionality of the device. This work aims to analyze surface parameters as, arithmetic average height (R a ), the maximum height of the profile (R t ), the average peak to valley height (R z DIN), chip formation and the geometric deviation of holes obtained by the previously referred manufacturing processes. The specimens, with cylindrical geometry, were made of titanium alloys, Ti- 6Al-4V and Ti-6Al-7Nb, currently used in the manufacture of medical devices. For this purpose, holes were made in a machining centre with different feed rate (F) for both methods and in the value of vertical step (a p ) in HM. The results obtained demonstrate that, at lower F and a p , HM presents better results. The Ti-6Al-7Nb alloy presents better roughness results compared to Ti-6Al-4V, validating it as a material able to be used in medical devices according to the fact that, a lower roughness is associated with higher corrosion resistance and fewer fatigue problems derived from it in components. By the work carried out, can be concluded that the roughness values obtained in HM are lower to those obtained by D making HM as a better option in hole making.publishe

Slow magnetic relaxation mechanisms in erbium SIMs

support by Fundação para a Ciência e a Tecnologia (FCT) under the scholarship SFRH/BD/ 84628/2012 and FRH/BPD/84173/2012. The CEMDRX group is grateful to FEDER (Programa Operacional Factores de Competitividade COMPETE) and from FCT-Fundação para a Ciência e a Tecnologia under the project PEst-C/FIS/UI0036/201

Guanidinium 4-amino­benzoate

In the title compound, CH6N3 +·C7H6NO2 −, the cation and anion lie on crystallographic mirror planes. The 4-amino­benzoate anion is almost in a planar conformation with a maximum deviation of 0.024 (2) Å for the N atom. The bond length in the deprotonated carboxyl group is inter­mediate between those of normal single and double Csp2=O bonds, indicating delocalization of the charge over both O atoms of the COO− group. In the crystal, N—H⋯O hydrogen bonds assemble the ions in layers propagating in the bc plane. This structure is very similar to that of guanidinium benzoate

Synthesis, structure and physical properties of luminescent Pr(III) ß-diketonate complexes

Near infrared lanthanide(III)-based light conversion molecular devices (LCMDs) are emerging as a promising class of materials for organic light-emitting diodes (OLEDs) in some niche technologies. Three of these molecular materials -two highly coordinated Pr3+ ß-diketonate monomers and a dimer- are presented and their structure and properties are discussed. Particular emphasis is placed on the solid-to-solid transformation observed for the homodinuclear compound