Synthetic precursor to make alkali activated cements

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Heteroaromatic alanine derivatives bearing (oligo)thiophene units : synthesis and photophysical properties

A series of new benzoxazolylalanine derivatives bearing (oligo)thiophene units at the side chain were synthesized in good yields. The photophysical characterization of these amino acids was performed by UV-vis absorption and fluorescence emission studies and revealed that some of the compounds display high fluorescent quantum yields, making them good candidates for application as fluorescent probes.Fundação para a Ciência e Tecnologia (FCT) - PTDC/QUI/66250/2006, bolsa de doutoramento SFRH/BD/35905/2007 atribuída a E. Oliveir

Exploring the emissive properties of new azacrown compounds bearing aryl, furyl or thienyl moieties: a special case of chelation enhancement of fluorescence upon interaction with Ca2+, Cu2+ or Ni2+

Three new compounds bearing furyl, aryl or thienyl moieties linked to an imidazo-crown ether system (1, 2 and 3) were synthesized and fully characterized by elemental analysis, infrared, absorption and emission spectroscopy, X-ray crystal diffraction, and MALDI-TOF-MS spectrometry. The interaction towards metal ions (Ca2+, Cu2+, Ni2+ and Hg2+) and F- has been explored in solution by absorption and fluorescence spectroscopy. Mononuclear and binuclear metal complexes using Cu2+ or Hg2+ as metal centers have been synthesized and characterized. Compounds 2 and 3 show a noticeable enhancement of the fluorescence intensity in the presence of Ca2+ and Cu2+ ions. Moreover compound 3 presents a dual sensory detection way by the modification of the fluorimetric and colorimetric properties in the presence of Cu2+ or Hg2+. The EPR studies in frozen solution and in microcrystalline state of the dinuclear Cu(II)2 complex revealed the presence of an unique Cu2+ type.Fundação para a Ciência e a Tecnologia (FCT)We are indebted to InOU Uvigo by project K914 122P 64702 (Spain) and FCT-Portugal by project PTDC/QUI/66250/2006 for financial support. The NMR spectrometers are part of the National NMR Network and were purchased in the framework of the National Programme for Scientific Re-equipment, contract REDE/1517/RMN/2005, with funds from POCI 2010 (FEDER) and FCT-Portugal. C.L. thanks Xunta de Galicia, Spain, for the Isidro Parga Pondal Research Program. E.O. and R.B. thank FC-MCTES (Portugal) by their PhD grants SFRH/BD/35905/2007 and SFRH/BD/36396/2007, respectively. We are gratefull to Dr. Cristina Nunez and Dr. Pablo Gonzalez from the REQUIMTE, Universidade NOVA de Lisboa, Portugal, for their important help with the crystallographic and EPR data, respectively, and Dr. Jose Luis Capelo from the University of Vigo, Spain, for the help with the MALDI-TOF-MS spectra

Imidazo-benzo-15-crown-5 ether bearing arylthienyl and bithienyl moieties as novel fluorescent chemosensors for Pd2+ and Cu2+

Novel fluorescent ionophores bearing imidazo-arylthienyl or imidazo-bithienyl pi-conjugated bridges functionalized with one or two fused benzo-15-crown-5 ethers as receptor units are reported. The sensing ability of the compounds in the presence of metallic cations (Li+, Na+, K+, Ca2+, Zn2+, Cu2+, Ni2+, Pd2+ and Hg2+) and fluoride ion was studied in MeCN/DMSO solutions by absorption and emission spectroscopy. The experimental results indicate that all compounds could act as selective fluorimetric sensors for Cu2+ and Pd2+ and also for the fluoride ion, in the case of the bis-substituted crown ether derivatives.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/QUI/66250/2006 (FCOMP-01-0124-FEDER-007428), SFRH/BD/36396/200

Synthesis and characterization of novel (oligo)thienyl-imidazo-phenanthrolines as versatile π-conjugated systems for several optical applications

A series of new heterocyclic chromophores 3-6 were synthesised in moderate to excellent yields by condensation of 5,6-phenantroline-dione with formyl-thiophene derivatives 1-2 in the presence of ammonium acetate in glacial acetic acid. These chromophores possess a (oligo)thienyl- π-conjugated system attached to an imidazophenanthroline moiety. These derivatives were evaluated concerning their solvatochromic properties, thermal stabilities and molecular optical nonlinearities.Fundação para a Ciência e Tecnologia (FCT) - projecto PTDC/QUI/66250/2006, bolsa de doutoramento a R.M.F. Batista SFRH/BD/36396/2007), (FCT-UNL) REQUIMTE

Synthesis and evaluation of bipendant-armed (oligo)thiophene crown ether derivatives as new chemical sensors

Three new (oligo)thiophene bipendant-armed ligands 2a-c, derived from 2-(aminomethyl)-15-crown-5, have been synthesized and characterized. Compounds 2a-c were prepared by reductive amination of the corresponding macrocycle with formyl thiophene derivatives 1a-c in the presence of NaBH(OAc)3 in fair to good yields. The photophysical properties of ligands 2a-c were studied and they were also evaluated as chemosensors in the presence of Na(I), Ag(I), Pd(II) and Hg(II) cations in acetonitrile solution.Fundação para a Ciência e a Tecnologia (FCT

Synthesis and solvatochromism studies of novel bis(indolyl)methanes bearing functionalized arylthiophene groups as new colored materials

The demand for dyes with solvatochromic properties has increased in the last few years, mainly due to their wide range of applications in the analytical and industrial fields, such as in the textile industry. The phenomenon of solvatochromism is associated with the differential solvation of the ground and excited states of the solvatochromic compounds, leading to an important tool for the study of the nature of solute–solvent interactions. In this paper we report the synthesis of new bis(indolyl)methane derivatives bearing arylthiophene spacers (2a–d) functionalized with electron-donating and electron- withdrawing groups, and the photophysical studies in different solvents, such as ethanol, acetonitrile, dichloromethane, trichloromethane, dimethylsulfoxide, diethylether and 1,4-dioxane. Aiming to explore their solvatochromic behavior in the ground and excited states, all solvents employed have different hydrogen-bond donor abilities. The largest colour modifications were visualized for compound 2b, the solution colours of which are orange in DMSO, blue in trichloromethane, green in dichloromethane and purple in 1,4-dioxane. A negative solvatochromism was observed in 2b and positive one in 2a, 2c and 2d.Fundação para a Ciência e a Tecnologia (FCT

New oligothienyl-imidazo-phenanthroline chromophores for NLO applications

A new series of oligothienyl-imidazo-phenanthrolines 3 were synthesised in good to excellent yields by condensation of 5,6-phenantroline-dione 2 with formyl-thiophene derivatives 1 in the presence of ammonium acetate in glacial acetic acid. Furthermore, their solvatochromism and molecular optical nonlinearities were determined and comparatively studied. The experimental results indicate that phenanthrolines 3, due to their moderate solvatochromic properties and good optical nonlinearities, could be used as suitable probes for the determination of solvent polarity and as nonlinear optical materials.Fundação para a Ciência e Tecnologia (FCT

(Oligo)thienyl-imidazo-benzocrown ether derivatives : synthesis, photophysical studies and evaluation of their chemosensory properties

A series of novel (oligo)thienyl-imidazobenzocrown ethers were synthesised through a simple method and evaluated as fluorimetric chemosensors for transition metal cations. Interaction with Ni2+, Pd2+, and Hg2+ in ACN/DMSO solution (99:1) was studied by absorption and emission spectroscopy. Chemoselectivity studies in the presence of Na+ were also carried out and a fluorescence enhancement upon chelation (CHEF) effect was observed following Hg2+ complexation. Considering that most systems using fluorescence spectroscopy for detecting Hg2+ are based on the complexation enhancement of the fluorescence quenching (CHEQ) effect, the present work represents one of the few examples for sensing of Hg2+ based on a CHEF effect.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/QUI/66250/2006, SFRH/BD/36396/2007, SRFH/BPD/72557/201