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Carbonation and corrosion of reinforced concrete structures (RCS) are the two main phenomena that more often affect civil engineering structures. The main consequence of carbonation is the pH reduction of concrete to values between 9 and 6 which may compromise the RCS durability. Thus, the development of sensors that would predict concrete carbonation is of utmost importance. Fiber optic sensors (OFS) are commonly used for concrete applications due to their high sensitivity and resistance to external interference. This work reports the synthesis of organic-inorganic hybrid (OIH) materials for possible functionalization of OFS and application in concrete and RCS. As precursors, 3-glycidyloxypropyltrimethoxysilane (GPTMS) and Jeffamine® THF-170 were used. The OIH sol-gel materials were doped with phenolphthalein (phph) for pH sensing proposes and cetyl trimethyl ammonium bromide (CTAB) as surfactant. OIH with pH sensing ability properties were successfully obtained and the doping of the OIH matrix did not significantly changed the dielectric properties of the resultant material. Moreover, the results obtained in simulated concrete pore solutions, obtained for the OIH produced, showed to be promising for application in fresh concrete. The transmittance of the synthesized OIH materials decreased after the doping. The matrix shows intrinsic fluorescence and doping it only led to small deviations in the wavelength of the peak of maximum emission. No significative changes were obtained on the thermal profile of the OIHs. The pH variation was shown by the OIH material color change. Stability studies regarding the release of phph from the OIH matrix indicates that the proposed system reveals long-term stability., Thanks are due to Fundaçã para a Ciência e Tecnologia (FCT) and FEDER (European Fund for Regional Development)-COMPETE-QRENEU for financial support through the Chemistry Research Centre of the University of Minho (Ref. CQ/UM (UID/QUI/00686/2019 and UID/QUI/00686/2020)), project “SolSensors — Development of Advanced Fiber Optic Sensors for Monitoring the Durability of Concrete Struc tures”, reference POCI-01-0145-FEDER-031220, a PhD grant to R. P. C. L. Sousa (SFRH/BD/145639/2019), a BSc grant to B. Ferreira and a Scientific Initiation grant to S. Sousa under the SolSensors project POCI 01-0145-FEDER-031220 is also acknowledged. Artur J. M. Valen tethanks the Coimbra Chemistry Centre and FCT for financial support (UID/QUI/00686/2020, UID/QUI/00313/2020).

A series of novel substituted-azo dyes 8-(aryldiazenyl)quinolin-5-ol (5a-i) were synthesized by the coupling reaction of 5-hydroxyquinoline with diazotized aniline derivatives in the presence of NaNO2 in HCl/H2O mixture. The study of the spectroscopic and solvatochromic properties were performed by FT-IR, 1H and 13C-NMR and UV-Visible spectroscopies. The tautomerism of these dyes was studied using the deuteration technique and solvatochromic measurements. Photochromic properties of these 5-hydroxyquinoline azo dyes were also examined via E/Z and Z/E photochemical isomerization reactions and compared with the existing 8-hydroxyquinoline analogous. The novel substituted-azo dyes exhibited higher Z/E thermal isomerization rates and have larger absorbance wavelength range than their 8-hydroxyquinoline analogous, making them potential molecular switches., FCT - Swinburne University of Technology(UID/QUI/00686/2020)

New porphyrin-imidazole derivatives were synthesised by Radziszewski reaction between 2-formyl-5,10,15,20-tetraphenylporphyrin 1 and several (hetem)aromatic 1,2-diones, which after cationization afforded promising monocationic photosensitizers 3a-d. Singlet oxygen studies have demonstrated that all the cationic porphyrin-imidazole conjugates 3a-d were capable to produce cytotoxic species. These photosensitizers were able to photoinactivate Eschericha coli and their inactivation profile was improved in the presence of KI., The authors are grateful to University of Aveiro and FCT/MCT for the financial support for QOPNA research Unit (FCT UID/QUI/00062/2019), the LAQV-REQUIMTE (UIDB/50006/2020), CESAM (UID/AMB/50017/2019) and CQUM (QUI/UI0686/2018) through national founds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement, and to the Portuguese NMR Network. The research contract of N.M.M. Moura (REF.-048-88-ARH/2018) is funded by national funds (OE), through FCT - Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.

The sensing behaviour toward metal cations and biothiols of two 2,4,5-triarylimidazole probes (3a and 3b) is tested in acetonitrile and in acetonitrile-water. In acetonitrile the two probes present charge-transfer absorption bands in the 320-350 nm interval. Among all cations tested only Cu(11) is able to induce bathochromic shifts of the absorption band in the two probes, which is reflected in marked colour changes. Colour modulations are ascribed to the formation of 1:1 Cu(II)-probe complexes in which the cation interacts with the imidazole acceptor heterocycle. Besides, the two probes present intense emission bands (at 404 and 437 nm for 3a and 3b respectively) in acetonitrile that are quenched selectively by Cu(11). Probe 3a is soluble in acetonitrile-water 1:1 (v/v) and Cu(11) also induces bathochromic shifts of the absorption bands. Moreover, the emission bands of probe 3a in this mixed aqueous solutions is quenched in the presence of Cu(II). The potential use of the 1:1 complex formed between 3a and Cu (II) for the chromo-fluorogenic detection of biothiols (GSH, Cys and Hcy) in aqueous environments is also tested. At this respect, addition of GSH, Cys and Hcy to acetonitrile-water 1:1 v/v solutions of 3a-Cu(11) complex induces a hypsochromic shift of the visible band (reflected in a bleaching of the solutions) with a marked emission increase at 470 nm., We thank the Spanish Government (MAT2015-64139-C4-1-R) and Generalitat Valenciana (PROMETEO 2018/024). H.E.O. thanks Generalitat Valenciana for his Grisolia fellowship. Thanks are also due to Fundação para a Ciência e Tecnologia (Portugal) for financial support to the Portuguese NMR network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETEQREN-EU for financial support to the research centre CQ/UM [Ref. UID/QUI/00686/2013 and UID/QUI/0686/2016], and a PhD grant to R.C.M. Ferreira (SFRH/BD/86408/2012).

The imidazole derivative 4-(4,5-diphenyl-1H-imidazol-2-yl)-N,N-dimethylaniline (probe 1) formed a highly coloured and non-emissive 1:1 stoichiometry complex with Cu(II) in water-acetonitrile 1:1 (v/v) solutions. Among all the amino acids (Lys, Val, Gln, Leu, His, Thr, Trp, Gly, Phe, Arg, Ile, Met, Ser, Ala, Pro, Tyr, Gly, Asn, Asp, Glu, Cys and Hcy) and tripeptides (GSH) tested, only GSH induced the bleaching of the 1·Cu(II) solution together with a marked emission enhancement at 411 nm (excitation at 320 nm). These chromo-fluorogenic changes were ascribed to a selective GSH-induced demetallation of the 1·Cu(II) complex that resulted in a recovery of the spectroscopic features of probe 1. In addition to the remarkable selectivity of 1·Cu(II) complex toward GSH a competitive limit of detection as low as 2 μM was determined using fluorescence measurements., We thank the Spanish Government (MAT2015-64139-C4-1-R) and Generalitat Valenciana (PROMETEOII/2014/047). H. E. O. thanks Generalitat Valenciana for his Grisolia fellowship. Thanks are also due to Fundação para a Ciência e Tecnologia (Portugal) for financial support to the Portuguese NMR network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDEReCOMPETEQREN-EU for financial support to the research centre CQUM (UID/QUI/0686/2016) and a doctoral grant to R.C.M. Ferreira (SFRH/BD/86408/2012). The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project No 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC)., info:eu-repo/semantics/publishedVersion

Several organic compounds have been used in optoelectronics devices; porphyrins, due to their interesting optical and electronic properties, have shown an attractive potential to be used on molecular electronics. Among other advantages, porphyrins easily coordinate with several metal ions, which allows the assembly with peripheral or axial ligands introducing new properties to the supramolecular porphyrin. In this work, a new metalloporphyrin system with 5,10,15,20-(tetra-p-tolyl)porphyrin (ttp) and iridium(III) where 4,4’-bipyridine (bpy) coordinate in the axial positions was successfully synthetized, through the formation of “shish kebab” structures. This new compound was characterized through ultraviolet-visible, proton nuclear magnetic resonance, Fourier-transform infrared and Raman spectroscopies, thermogravimetry, differential scanning calorimeter and cyclic voltammetry. The introduction of the bpy on the metalloporphyrin moiety exhibited important influence on the optical, thermal and electrochemical properties., The authors acknowledge the Portuguese Foundation of Science and Technology (TSSiPRO – TECHNOLOGIES FOR SUSTAINABLE AND SMART INNOVATIVE PRODUCTS – NORTE-01-0145-FEDER-000015) and UID/CTM/50025/2013 for the financial support., info:eu-repo/semantics/publishedVersion

A series of benzothiadiazole-based push-pull heterocyclic systems were synthesized and characterized in order to study the variations induced by different aromatic and heterocyclic donor groups in the optical, electronic and photovoltaic properties of DSSCs prepared with the respective cyanoacetic acid derivatives. The organic sensitizers bear a 5-hexyl-2,2’-bithienyl or N,N-diphenylanilino donor moieties conjugated with a thienyl-benzothiadiazole spacer functionalized with the electron acceptor/anchoring cyanoacetic acid group. The solar cell based on TiO2 sensitized with the novel dye bearing the 5-hexyl-2,2’-bithienyl donor, exhibited a power conversion efficiency of 0.95 % due the inefficient electron injection. Co-adsorption studies of the same dye resulted in enhanced photovoltaic conversion efficiency of 2.49 %, which represents an improvement of cell efficiency of 260 %. The sensitizer bearing the N,N-diphenylanilino donor exhibited 4.51 % power conversion efficiency, that was further enhanced by co-sensitization to 5.22 % efficiency., Thanks are due to Fundação para a Ciência e Tecnologia (FCT) for a PhD grant to S. S. M. Fernandes (SFRH/BD/87786/2012) and FEDERCOMPETE for financial support through the CQ/UM (Ref. UID/QUI/ 00686/2013 and UID/QUI/0686/2016). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT. A. Pereira, D. Ivanou, and A. Mendes would like to acknowledge the European Commission through the Seventh Framework Programme, the Scientific Programme “Ideas” of the European Research Council for research and technological development as part of an Advanced Grant under grant agreement No 321315, which also partially funded this work., info:eu-repo/semantics/publishedVersion

Highly emissive heterocyclic alanines bearing a benzo[d]oxazolyl unit functionalised with pyrrole and imidazole at the side chain were synthesised and evaluated as fluorimetric chemosensors for different anions and metal cations. The results obtained by UV-Vis and fluorescence titrations as well as 1H NMR titrations indicate that there is a strong interaction through the donor N and O atoms at the side chain of the benzoxazolyl-alanines, with high selectivity towards Cu2+ and Pd2+ in a ligand-to-metal complex with 1:2 stoichiometry, and association constants were calculated for some ions. The photophysical and ion sensing properties of these unnatural amino acids suggest that they can be used to obtain bioinspired frameworks for metal ion recognition such as peptides/proteins with chemosensory/probing ability., Thanks are due to Fundação para a Ciência e Tecnologia (FCT-Portugal) and FEDER-COMPETE for financial support through the CQ/UM (Ref. UID/QUI/00686/2013 and UID/QUI/0686/2016) and a PhD grant to C.I.C. Esteves (SFRH/BD/68360/2010) and R.C.M. Ferreira (SFRH/BD/86408/2012). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT., info:eu-repo/semantics/publishedVersion

A series of push-pull aryl-bithiophene based systems 2-3 were designed and synthesized in order to understand how structural modifications influence the electronic, linear and nonlinear optical properties. The push-pull conjugated chromophores 2-3 bear a bithiophene spacer conjugated with a phenyl ring functionalized with N,N-dialkylamino electron-donor groups together with cyanoacetic or rhodanine-3-acetic acid acceptor groups. Theoretical (DFT calculations) and experimental studies were carried out to obtain information on conformation, electronic structure, electron distribution, dipolar moment, and molecular nonlinearity response of the push-pull bithiophene derivatives. This multidisciplinary study revealed that chromophore 2e exhibits the highest value for hyperpolarizability beta (10440 × 10-30 esu) due to the strong electron donating ability of the N,N-diethylamino group, and the ethyne linker that not only lengthens the pi- conjugation path but also grants less distortion to the system., Thanks are due to Fundação para a Ciência e Tecnologia (FCT) for a PhD grant to S. S. M. Fernandes (SFRH/BD/87786/2012) and FEDERCOMPETE for financial support through the CQ/UM (Ref. UID/QUI/ 00686/2013 and UID/QUI/0686/2016). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Reequipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT. The pulsed laser system was acquired within the framework of the grant (PTDC/CTM/105597/2008) from the Fundação para a Ciência e Tecnologia (FCT) with funding from FEDERCOMPETE. This work was also supported by the Associated Laboratory for Sustainable Chemistry - Clean Processes and Technologies - LAQV which is financed by Portuguese national funds from FCT/MEC (UID/ QUI/50006/2013) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER–007265)., info:eu-repo/semantics/publishedVersion

Five push-pull heterocyclic dyes 4-7, and 9 were synthesized and characterized in order to study the variations in the optical, electronic and photovoltaic properties induced by structural modifications, i.e. different spacer units and anchoring groups. The final push-pull conjugated dyes 6-7 and 9 are formed by a N,N-dimethylaniline donor moiety conjugated with bithiophene, ethynyl-bithiophene or ethynyl-thieno[3,2-b]thiophene spacers and cyanoacetic acid or rhodanine-3-acetic acid as anchoring group. The synthesis of the precursor aldehydes 4-5 was accomplished through a Sonogashira coupling, on the other hand, compound 8 was prepared by Suzuki coupling. Knoevenagel condensation of aldehydes 4, 5 and 8 with cyanoacetic acid or rhodamine-3-acetic acid afforded the final push-pull dyes 6, 7 and 9. Information on conformation, electronic structure and electron distribution was obtained by DFT and TDDFTcalculations. This multidisciplinary study regarding the evaluation of the optical, redox and photovoltaic properties of the dyes reveals that compound 7, bearing an ethynyl-bithiophene spacer conjugated with a cyanoacetic acid anchoring group, has the highest conversion efficiency (3.51 %) as dye sensitizer in nanocrystalline TiO2 solar cells. Co-adsorption studies were also performed for dyes 6-7 with N719 as co-adsorbent, and this enhanced dye efficiencies by 33-45 %. The best cell performance was obtained by co-adsorbing N719 and dye 7 (75/25 vol%) with 4.66 % efficiency., Laboratory for Advanced Computing at the University of Coimbra, Thanks are due to: Fundaçao para a Ci ~ encia e a Tecnologia for ^ PhD grants to S. S. M. Fernandes (SFRH/BD/87786/2012), and I. Mesquita (PD/BD/105985/2014) and a postdoctoral grant to L.L.G.Justino. (SFRH/BPD/97026/2013); FEDER-COMPETE for financial support through the CQ/UM PEst-C/QUI/UI0686/2013 (FCOMP- 01-0124-FEDER-037302); European Research Council (Contract no: 321315) for funding. H. D. Burrows are grateful for funding from Centro de Química de Coimbra, which is supported by the FC through the programmes UID/QUI/UI0313/2013 and COMPETE. The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/ RMN/2005 with funds from POCI 2010 (FEDER) and FCT. The authors also thank the Laboratory for Advanced Computing at the University of Coimbra for providing computing resources that have contributed to the research results reported in this paper (URL http://www.lca.uc.pt). The authors would like also to acknowledge A. I. Pereira for sequential co-adsorption devices and Dr. D. Ivanou for IPCE experiments., info:eu-repo/semantics/publishedVersion

Novel fluorescent 4,5-diarylimidazolyl-phenylalanines 3a-d were prepared by reaction of N-tert-butyloxycarbonyl-4-formylphenylalanine methyl ester and appropriate (hetero)aromatic diones. The photophysical properties of these new unnatural amino acids were evaluated by UV-Vis absorption and fluorescence spectroscopy in solvents of different character and aqueous mixtures with acetonitrile. They were evaluated as novel amino acid based fluorimetric chemosensors for ions through spectrophotometric and spectrofluorimetric titrations with biologically and analytically important anions and cations such as F-, OH-, Cu2+ and Fe3+. The results indicate that there was a strong interaction through the donor N, O and S atoms at the side chain, especially for 4,5-di(furan-2’-yl)imidazolyl-phenylalanine 3a and 4,5-di(thiophen-2’-yl)imidazolyl-phenylalanine 3b with Cu2+ and Fe3+, in a 1:1 complex stoichiometry. The photophysical and metal ion sensing properties of these amino acids suggest that they can be suitable for incorporation into chemosensory peptidic frameworks., Thanks are due to Fundação para a Ciência e Tecnologia (FCT-Portugal) and FEDER-COMPETE for financial support through Centro de Química [PEst-C/QUI/UI0686/2011 (F-COMP-01-0124-FEDER-022716)] and a PhD grant to C.I.C. Esteves (SFRH/BD/68360/2010). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased with funds from FCT and FEDER., info:eu-repo/semantics/publishedVersion

[EN] Four imidazoquinolines functionalized with different carbocycles and heterocycles were synthesized and characterized. Acetonitrile solns. of the four receptors presented absorption bands in the 330-370 nm range. The four probes were also emissive with fluorescence bands in the 390-460 nm interval. In a 1st step, the chromo-fluorogenic behavior of the four probes was evaluated in the presence of selected anions. Addn. of F- induced the appearance of a new red shifted absorption band together with a moderate quenching of the fluorescence in all four receptors. In a 2nd step, the UV-​visible and emission behavior of the four receptors in the presence of cations was tested. Addn. of Hg2+, Cu2+, Co2+, Fe3+, Fe2+, Zn2+, Pb2+, Cd2+, Cr3+ and Al3+ induced a similar optical change in all four receptors (appearance of a broad red shifted absorption band together with a remarkable quenching of the emission band)., We thank the Spanish Government (project MAT2012-38429-C04) and the Generalitat Valenciana (project PROMETEO/2009/016) for support. C. Marin-Hernandez thanks the Spanish Ministry of Economy and Competitiveness for her grant. Thanks are also given to the Fundacion Carolina and UPNFM-Honduras for a doctoral grant to L. E. Santos-Figueroa and to Generalitat Valenciana for Santiago Grisolia fellow to Sameh El Sayed. Thanks are also due to the Fundacao para a Ciencia e Tecnologia (Portugal) and FEDER-COMPETE for financial support through the Centro de Quimica - Universidade do Minho, Project PEst-C/QUI/UI0686/2013 (FCOMP-01-0124-FEDER-037302) and a Post-doctoral grant to R.M.F. Batista (SFRH/BPD/79333/2011). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, with funds from FCT. We are also grateful to the Instituto da Educacao of Universidade do Minho for providing the laboratory infrastructure necessary for the development of this work.

Novel receptors based on imidazo-anthraquinone system containing thiazole, (benzo)furan, thiophene and imidazole heterocycles at position 2 were synthesized. The photophysical properties of compounds 1-8 were studied by UV-vis and fluorescence spectroscopy in acetonitrile. All anthraquinone derivatives exhibited great selectivity for the cyanide anion over other anions in acetonitrile/water (9:1) solution showing a distinct colour change from yellow to orange and the fluorescence emission was switched “off”. The binding stoichiometry between the receptors and the anions was found to be 1:1. Moreover, chemosensors 1-8 exhibit a high sensitivity being capable to detect cyanide in very low concentrations (below 4 microM)., Fundação para a Ciência e a Tecnologia (FCT)

A series of arylfuryl-bis(indolyl)methane derivatives were prepared in good yields by electrophilic substitution of indole with furyl aldehydes through a simple and mild hydrogensulfate-catalysed reaction and studied as chemosensors for transition metal cations by performing spectrophotometric and spectrofluorimetric titrations. Selective recognition of Hg2+ was achieved in organic aqueous mixture (CH3CN/H2O, 7:3) for the various receptors, with an easily detectable colour change from colourless to purple and also through a fluorescence quenching, making these compounds suitable for dual chromoand fluorogenic ratiometric sensing of Hg2+. The binding stoichiometry between the receptors and Hg2+ was found to be 1:1. The binding process was also followed by 1H NMR titrations which corroborated the previous findings., Fundação para a Ciência e a Tecnologia (FCT)

The thermal stability of poly(3-hexylthiophene) (P3HT) in its molten state was investigated in air and nitrogen atmospheres under no illumination conditions, with the aim of testing the feasibility of processing it using polymer melt techniques. A large set of different experimental characterization techniques was used including thermogravimetric analysis (TGA), rotational rheometry, infrared spectroscopy (FTIR-ATR), proton nuclear magnetic resonance spectroscopy (1H-NMR), gel permeation chromatography (GPC), UVVis and fluorescence spectroscopy. The results obtained strongly suggest that the processing of P3HT in its molten state is possible, without noticeable degradation, if carried out under nitrogen atmosphere and if the processing (residence) times are relatively short. Conversely, as expected, in a normal air atmosphere P3HT degrades rapidly at temperatures above its melting point. The effect of PCBM on the thermal stability of P3HT:PCBM blends in the molten state was also studied using TGA, and in air atmosphere PCBM is shown to delay oxidation., Thisworkwas supported by FCT (Fundação para a Ciência e Tecnologia) through the program PEst-C/CTM/LA0025/ 2013 (Projecto Estratégico - LA 25 - 2013-2014 - Strategic Project - LA 25 - 2013-2014) and by the European Regional Development Fund (FEDER) through the program COMPETE (project PTDC/CTM-POL/120843/2010). A.S.F.F. thanks FCTfor a post-doc fellowship(SFRH/BPD/73060/2010).

Novel colorimetric and fluorimetric chemosensors for F− and CN− containing anthraquinone and imidazole as signalling/binding sites have been synthesised and characterised. Upon addition of F−, CN− and OH− to acetonitrile solutions of compounds 1-2, a marked colour change from yellow to pink was observed and the fluorescence emission of 1 was switched “on”, whereas for 2 there was a fluorescence quenching. Considering recognition in organic aqueous mixture, it was found that selectivity for CN- was achieved for both receptors, with an easily detectable colour change from yellow to orange. Compounds 1-2 in their deprotonated form, after fluoride addition, were studied as metal ion chemosensors and displayed a drastic change from pink to yellow after metal ion complexation giving a yellow-pink-yellow, reversible colorimetric reaction and a “on-off-on” fluorescence in acetonitrile. The binding stoichiometry between the receptors and the anions and cations was found to be 1:1 and 2:1 respectively. The binding process was also followed by 1H NMR titrations which corroborated the previous findings., Fundação para a Ciência e Tecnologia (FCT)

A family of heterocyclic thiosemicarbazone dyes (3a-d) containing thienyl groups has been synthesized, characterized, and their chromo-fluorogenic response in acetonitrile in the presence of selected anions was studied. Acetonitrile solutions of 3a-d show absorption bands in the 338-425 nm range, which are modulated by the groups attached to the thiosemicarbazone moiety. The fluoride, chloride, bromide, iodide, dihydrogen phosphate, hydrogen sulfate, nitrate, acetate, and cyanide anions were used in the recognition studies. Only sensing features were observed for fluoride, cyanide, acetate, and dihydrogen phosphate anions. Two different chromogenic responses were found, (i) a small shift of the absorption band due to coordination of the anions with the thiourea protons and (ii) the appearance of a new red-shifted band due to deprotonation of the receptor. For the latter process changes in the color solutions from pale-yellow to orange-red were observed. Fluorescence studies showed a different emission behavior according to the number of thienyl rings in the pi-conjugated bridges. Stability constants for the two processes (complex formation+deprotonation) for receptors 3a-d in the presence of fluoride and acetate anions were determined from spectrophotometric titrations using the HypSpec program. The interaction of 3d with fluoride was studied through H-1 NMR titrations. Semiempirical calculations to evaluate the hydrogen-donating ability of the receptors were also performed. (C) 2012 Elsevier Ltd. All rights reserved., We thank the Spanish Government (project MAT2009-14564-C04-01) and the Generalitat Valencia (project PROMETEO/2009/016) for support. Thanks are due to the Fundacao para a Ciencia e Tecnologia (Portugal) and FEDER-COMPETE for financial support through the Centro de Quimica - Universidade do Minho, Project PEst-C/QUI/UI0686/2011 (F-COMP-01-0124-FEDER-022716) and a Post-doctoral grant to R.M.F.B. (SFRH/BPD/79333/2011). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, with funds from FCT. The authors are also indebted to program 'Accoes Integradas Luso-Espanholas/CRUP', for the bilateral agreement number E-144/10. Thanks also to Fundacion Carolina and UPNFM-Honduras for a doctoral grant to L.E.S.-F. and the Spanish Ministerio de Ciencia e Innovacion for an FPU grant to M.E.M..

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/36396/2007

The interaction of four fluorescent compounds containing thiophene and benzoxazole moieties combined with an alanine residue with alkaline, alkaline-earth, transition and post-transition metal ions was explored. The highly fluorescent heterocyclic alanine derivatives are strongly quenched in the solid state after complexation with the paramagnetic metal ions Cu2+ and Ni2+, and with the diamagnetic Hg2+. Absorption and steady-state fluorescence titrations reveals a selective interaction with Cu2+, Ni2+ and Hg2+. In all cases the formation of mononuclear or dinuclear metal complexes in solid state and in solution are postulated. DFT calculations on the mercury(II) complexes confirm the formation of dinuclear species. Our results suggest that one metal ion is coordinated by the chelate group formed by the amine and carboxylic groups presents in the amino acid residue and the second metal ion directly linked to the chromophore. As parent compound, L4 shows no interaction with Cu2+ and Ni2+ salts. However, the interaction with Hg2+ induces a strong quenching and a red shift of the fluorescence emission., Fundação para a Ciência e a Tecnologia (FCT), Universidade do Minho (UM)

A series of emissive N-t-butyloxycarbonyl benzyl ester asparagines bearing benzothiazole and benzimidazole units at the side chain, functionalised with electron donor or acceptor groups, were evaluated as novel amino acid based fluorimetric chemosensors for transition metal cations such as Cu2+, Zn2+, Co2+ and Ni2+. Selective removal of the protecting groups at the N- and C-terminals was carried out in order to assess the influence of the presence of blocking groups on the overall coordination ability. The results indicate that there is a strong interaction through the donor N, O and S atoms at the side chain of the various asparagines, with high selectivity towards Cu2+ in a 1:1 complex stoichiometry. Association constants and detection limits for Cu2+ were calculated. The photophysical and metal ion sensing properties of these asparagines suggest that they can be suitable for incorporation into peptidic chemosensor frameworks., Fundação para a Ciência e a Tecnologia (FCT)

The photochromic behaviour of two series of 2,2’-bithiophene azo dyes in THF solutions was studied. The photochromic properties and colour constancy were strongly dependent on the substitution pattern of the dyes. Under visible irradiation (> 420 nm) while some dyes exhibited a significant change in the colour intensity others exhibited an almost stable absorption. The photokinetic parameters of these systems are described., Fundação para a Ciência e a Tecnologia (FCT)

A series of formyl-substituted 5-aryl-2,2´-bithiophenes 5 were synthesized using two different methods: Vilsmeier-Haack-Arnold reaction (VHA) or through Suzuki coupling. The synthesis of compounds 5 through the Vilsmeier-Haack-Arnold reaction, starting from inexpensive and easily available precursors such as acetophenones, gave the title compounds in low yields after four reaction steps. On the other hand Suzuki coupling of functionalized aryl boronic acids 7 and the 5-bromo-5´-formyl-2,2´-bithiophene 6 gave compounds 5 in good yields in only one step., Fundação para a Ciência e a Tecnologia (FCT)

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.

A series of new bis-alanine derivatives bearing (oligo)thiophene and benzoxazole units as the heteroaromatic bridge were synthesized in moderate to good yields. The photophysical characterization of these bis-amino acids was performed by UV-visible absorption and fluorescence emission studies and revealed that the compounds displayed exceptionally high fluorescence quantum yields, making them good candidates for application as fluorescent probes when incorporated into peptides, as well as peptide conformationrestricting and cross-linking elements., Fundação para a Ciência e Tecnologia (FCT) projecto PTDC/QUI/66250/2006, bolsa de doutoramento SFRH/BD/36396/2007 atribuída R.M.F. Batista

A series of bithienyl azo dyes has been prepared from their corresponding coupling components, 5-alkoxy-2,2´-bithiophenes. The solvatochromic behavior of the compounds was investigated. The hyperpolarizabilities β of derivatives 3-5 were measured using hyper-Rayleigh scattering and thermogravimetric analysis (TGA) was used to evaluate their thermal stability. The experimental results indicate that, good nonlinearity-thermal stability is well balanced for azo-bithiophene NLO-chromophores 3-5 making them good candidates for NLO applications., Fundação para a Ciência e Tecnologia.

The photochromic behaviour of thienylpyrrole azo dyes in THF solutions was studied for the first time. The photochromic properties are strongly dependent on the substitution pattern on the dyes. Nitro-substituted thienylpyrrole azo dyes are particularly interesting since they exhibit very fast colouration/decolouration processes. The activation energies of these compounds are among the lowest values reported for heterocyclic azo dyes. These compounds show aggregation phenomena in freshly prepared solutions of THF, which lead to variable photochromic behaviours. Only after 1–5 h the solutions reach equilibrium and then reproducible photochromic behaviour can be observed., Fundação para a Ciência e Tecnologia (FCT), To FCT (Portugal’s Foundation for Science and Technology) and FEDER for financial support to the research units Centro de Química-Vila Real (POCTI-SFA-3-616) and Centro de Química-Universidade do Minho (POCTI/QUI/37816/2001). We also thank Dr. Kevin Yager (McGill University) for the helpful suggestions and the group of University of Minho is also grateful to Professor G. Kirsch (University of Metz).

The encapsulation of a pyridazine Cr(III) complex was prepared from a robust biosorption system consisting of a bacterial biofilm supported on NaY or NaX zeolites. The maximum removal efficiency was 20% for Cr in both systems based in NaY or NaX. The bacterial biofilm, Arthrobacter viscosus, supported on the zeolite reduce Cr(VI) to Cr(III). The Cr(III) is retained in the zeolite by ion exchange. These occluded complexes were characterized by chemical analysis, spectroscopic methods (FTIR and UV/Vis) and surface analysis (DRX). The various techniques of characterization used show that the Cr(III) complex was effectively encapsulated in the zeolite and this process does not modified the morphology and structure of the NaY/NaX zeolites. These materials have potential applications in heterogeneous catalysis in mild conditions., Departamento de Ciências da Terra of Universidade do Minho; Fundação para a Ciência e a Tecnologia (FCT)

Tricyanovinyl-substituted 1-(alkyl)aryl-2-(2´-thienyl)pyrroles 1 have been synthesized by direct tricyanovinylation reaction of 1-(alkyl)aryl-2-(2´-thienyl)pyrroles 2 using TCNE. The tricyanovinyl- derivatives 1 display dramatic reductions in both their optical and electrochemical band gaps relative to thienylpyrrole precursors 2. The solvatochromic behavior of compounds 1 was investigated in a variety of solvents. Hyper-Rayleigh scattering was used to measure the first hyperpolarizabilities β of the mentioned compounds. The β values show that the new compounds prepared could be used on the manufacture of materials with good non-linear (NLO) properties., Fundação para a Ciência e Tecnologia (FCT) - POCTI, FEDER (ref.POCTI/QUI/37816/2001).

New molecular systems based on donor/acceptor groups connected by π-conjugated bridge, trans-[MoF(NNC7H6SO2)(Ph2PCH2CH2PPh2)2][BF4], have been synthesized. This complex with nonlinear optical (NLO) applications was immobilized by an adsorption process from liquid phase, in the interlayer of a pillared clay (PILC). The metal complex and the new materials were characterized by thermal analysis (DSC), chemical analysis, surface techniques (XPS), X-ray powder diffraction (XRD), nitrogen adsorption isotherms, spectroscopic methods (NMR, FT-IR and UV/Vis) and electrochemical measurements. The studies of the electrochemical and the spectroscopic properties of the complex show interactions between donor and acceptor groups across the conjugated bridge. The results obtained from the studies using different techniques of analysis confirm that the molybdenum complex was effectively immobilized in the host matrix and this process does not modify the morphology or structure of the PILC upon metal complex loading., Dr. Carmen Serra Rodrigues (C.A.C.T.I., Vigo University, Spain) is gratefully acknowledged for performing and analyzing the XPS measurements. We thank António Souza Azevedo for collecting the powder diffraction data. This work was supported by the Fundação para a Ciência e a Tecnologia (FCT, Portugal) through project POCTI/42931/QUI/2001., info:eu-repo/semantics/publishedVersion

This chapter deals with the Langmuir–Blodgett and self-assembled polymeric films. The growing interest in organic materials requires research that can be broadly divided into four main categories—namely, (1) material design, (2) synthesis, (3) processing and characterization, and (4) testing for applications. Having the designed material synthesized, in most cases an important step prior to testing a proposed application is the processing of the materials into a desired form, preferably in the form of ultrathin films that often possess a large surface area. For organic materials, in particular, the most commonly used techniques are simple drop casting, spin casting, dip coating, Langmuir–Blodgett technique, and self-assembly. A common feature in all these techniques is that the material of interest is first dissolved in a suitable solvent, being subsequently either physisorbed or chemisorbed onto a surface. The Langmuir–Blodgett and the self-assembly methods are looked upon as viable means of producing ultrathin films with controllable film thickness and molecular packing. While the former technique involves the formation of a monolayer film at the air-water interface and subsequent transfer as a multilayer film onto a solid substrate, the latter technique is essentially based on the ionic interaction between alternate layers.

Gama-Keto esters (2) derivatives of thiophene were obtained from hemi-succinic esters and transformed to the corresponding amides (4). Lawesson´s treatment of 2 and 4 gave the corresponding bithiophenes (5) with alkoxy or amino substituents., Thanks are due to FCT through IBQF (UM), ICCTI/French Embassy (Technical and Scientific Cooperation Programme) and to Dra. A.M.F. Oliveira-Campos for the interesting discussions.

8,10-Dimethoxyellipticine has been synthesised from readily available benzene derivatives via palladium acetate or photochemical cyclisation of intermediate diphenylamine derivatives. The route has advantages over indole based syntheses., We thank the British Council for awards under the Treaty of Windsor Programme and JNICT (IBQF - UM) Portugal for financial support., info:eu-repo/semantics/publishedVersion