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We report on the preparation and optical characterization of three dimensional colloidal photonic crystal (PhC) containing an engineered planar defect embedding photoactive push-pull dyes. Free standing polystyrene films having thickness between 0.6 and 3 µm doped with different dipolar chromophores were prepared. These films were sandwiched between two artificial opals creating a PhC structure with planar defect. The system was characterized by reflectance at normal incidence angle (R), variable angle transmittance (T) and photoluminescence spectroscopy (PL) Evidence of defect states were observed in T and R spectra which allow the light to propagate for selected frequencies within the pseudogap (stop band).

Insomnia is a frequent symptom in depressed patients. It can present with difficulty in initiating and/or maintaining sleep. We retrospectively evaluated a group of 15 patients affected by major depressive disorder and complaining of insomnia, who started vortioxetine (VOR) treatment for their depressive symptoms. The following questionnaires were captured at baseline and follow‐up: Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and Beck Depression Inventory. Pittsburgh Sleep Quality Index total score significantly decreased between follow‐up and baseline (P < 0.01), and in several subitems related to sleep quality and continuity. Moreover, Epworth Sleepiness Scale decreased between follow‐up and baseline (P < 0.01). Finally, Beck Depression Inventory reduction was also evident between follow‐up and baseline (P < 0.01). This retrospective analysis showing the significant effect of VOR on both depressive symptoms and insomnia in patients showing comorbid major depressive disorder and insomnia invites further research in order to confirm this preliminary evidence. We hypothesize that the VOR mechanism of action may explain the improvement of subjective sleep, other than depressive symptoms. [ABSTRACT FROM AUTHOR]

In the field of minimally invasive neurosurgery, microscopic transsphenoidal surgery (MTS) and endoscopic transsphenoidal surgery (ETS) have been widely accepted as a safe approach for pituitary lesions and, more recently, their indications have been extended to lesions at various skull base regions. It is mandatory during transsphenoidal surgery (TS) to identify key anatomical landmarks in the sphenoid sinus and distinguish them from the lesion. Over the years, many intraoperative tools have been introduced to improve the neuronavigation systems aiming to achieve safer and more accurate neurosurgical interventions. However, traditional neuronavigation systems may lose the accuracy of real-time location due to the discrepancy between the actual surgical field and the preoperative 2D images. To deal with this, augmented reality (AR)—a new sophisticated 3D technology that superimposes computer-generated virtual objects onto the user’s view of the real world—has been considered a promising tool. Particularly, in the field of TS, AR can minimize the anatomic challenges of traditional endoscopic or microscopic surgery, aiding in surgical training, preoperative planning and intra-operative orientation. The aim of this systematic review is to analyze the potential future role of augmented reality, both in endoscopic and microscopic transsphenoidal surgeries.

Di-branched dyes based on a triphenylamino (TPA) donor core have been functionalized with different aromatic and heteroaromatic peripheral groups bonded to TPA as auxiliary donors and investigated as sensitizers in DSSC. The different aromatic and heteroaromatic substitution significantly perturbed the optical properties of the dyes compared to the unsubstituted TPA reference dye, in turn leading to enhanced photovoltaic performances in terms of photocurrent, photovoltage, and power conversion efficiency (PCE). The enhancement originated from improved strategic interface interactions between the dye-sensitized titania and the liquid electrolyte, as ascertained by current–voltage, quantum efficiency (IPCE), light harvesting properties (LHE), and impedance spectroscopy (EIS) studies. [ABSTRACT FROM AUTHOR]

A thiophene-based donor–acceptor phenothiazine dye has been functionalized with a peripheral glucose unit (PTZ-GLU) to bust its affinity to water and enhance dye-sensitized photogeneration of hydrogen. Compared to the corresponding alkyl derivative (PTZ-ALK), as well as the common hydrophilic triethylene glycol substitution (PTZ-TEG), the sugar derivative shows a lower contact angle; PTZ-GLU performed twice more efficient than PTZ-TEG in the photogeneration of hydrogen in terms of evolved gas and turnover number. [ABSTRACT FROM AUTHOR]

Introduction: Sleep problems commonly occur in Parkinson's disease (PD) and significantly affect patients' quality of life. A possible effect on subjective sleep disturbances of monoamine oxidase-B inhibitors (MAOB-Is) has been described., Methods: This prospective, observational, single-centre study involved 45 fluctuating PD patients complaining sleep problems as documented by the PD Sleep Scale -2nd version (PDSS-2 ≥18) starting rasagiline 1 mg/daily or safinamide 100 mg/daily, according to common clinical practice, and maintaining antiparkinsonian therapy unchanged. Polysomnography (PSG), sleep questionnaires (PDSS-2, Epworth Sleepiness Scale - ESS), and motor function were evaluated at baseline (T0) and after 4 months of treatment (T1)., Results: Safinamide was prescribed in thirty patients and rasagiline in fifteen patients. Both drugs induced a significant improvement in Movement Disorder Society Unified PD Rating Scale III scores. Patients treated with rasagiline showed a significant increase in stage 1 (N1) Non-REM sleep compared to T0, with no significant effects on sleep scales. Patients treated with safinamide showed a significant increase in stage 3 of Non-REM sleep and sleep efficiency and a reduction in the rate of periodic limb movements, matching a significant reduction in PDSS-2 and ESS scales compared to T0., Conclusion: This study showed that safinamide, in addition to having a significant effect on PD motor symptoms, like the other MAOB-Is, may exert a specific beneficial effect on subjective and objective sleep, probably driven by its dual mechanism of action, which involves both dopaminergic and glutamatergic neurotransmission., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Decades of neuroimaging studies have shown modest differences in brain structure and connectivity in depression, hindering mechanistic insights or the identification of risk factors for disease onset 1 . Furthermore, whereas depression is episodic, few longitudinal neuroimaging studies exist, limiting understanding of mechanisms that drive mood-state transitions. The emerging field of precision functional mapping has used densely sampled longitudinal neuroimaging data to show behaviourally meaningful differences in brain network topography and connectivity between and in healthy individuals 2-4 , but this approach has not been applied in depression. Here, using precision functional mapping and several samples of deeply sampled individuals, we found that the frontostriatal salience network is expanded nearly twofold in the cortex of most individuals with depression. This effect was replicable in several samples and caused primarily by network border shifts, with three distinct modes of encroachment occurring in different individuals. Salience network expansion was stable over time, unaffected by mood state and detectable in children before the onset of depression later in adolescence. Longitudinal analyses of individuals scanned up to 62 times over 1.5 years identified connectivity changes in frontostriatal circuits that tracked fluctuations in specific symptoms and predicted future anhedonia symptoms. Together, these findings identify a trait-like brain network topology that may confer risk for depression and mood-state-dependent connectivity changes in frontostriatal circuits that predict the emergence and remission of depressive symptoms over time., (© 2024. The Author(s).)

Electrochemical nitrogen reduction (E-NRR) is one of the most promising approaches to generate green NH 3 . However, scarce ammonia yields and Faradaic efficiencies ( FE ) still limit their use on a large scale. Thus, efforts are focusing on different E-NRR catalyst structures and formulations. Among present strategies, molecular electrocatalysts such as metal-porphyrins emerge as an encouraging option due to their planar structures which favor the interaction involving the metal center, responsible for adsorption and activation of nitrogen. Nevertheless, the high hydrophobicity of porphyrins limits the aqueous electrolyte-catalyst interaction lowering yields. This work introduces a new class of metal-porphyrin based catalysts, bearing hydrophilic tris(ethyleneglycol) monomethyl ether chains (metal = Cu(II) and CoII)). Experimental results show that the presence of hydrophilic chains significantly increases ammonia yields and FE , supporting the relevance of fruitful catalyst-electrolyte interactions. This study also investigates the use of hydrophobic branched alkyl chains for comparison, resulting in similar performances with respect to the unsubstituted metal-porphyrin, taken as a reference, further confirming that the appropriate design of electrocatalysts carrying peripheral hydrophilic substituents is able to improve device performances in the generation of green ammonia., Competing Interests: The authors declare no conflict of interest., (© 2024 The Authors. Global Challenges published by Wiley‐VCH GmbH.)

Epilepsy is increasing, being more common in older adults, with more than 20% of late-onset cases with unknown aetiology (LOEU). Although epilepsy was associated with cognitive impairment, few studies evaluated the trajectories of cognitive decline in patients with LOEU. The present study aimed at assessing biomarkers of Alzheimer's disease (AD) in patients with LOEU and evaluating their cognitive performance for 12 months. For this study, 55 patients diagnosed with LOEU and 21 controls were included. Participants underwent cognitive evaluation and cerebrospinal fluid (CSF) biomarker analysis (ß-amyloid 42 , tau proteins) before starting anti-seizure medication and then repeated the cognitive evaluation at the 12-month follow-up. A subgroup of LOEU patients and controls also performed 18 F-fluoro-2-deoxy-D-glucose positron emission tomography ( 18 F-FDG PET) before starting anti-seizure medication. At baseline, LOEU patients showed lower Mini-Mental State Examination (MMSE) score, worse cognitive performance in several domains, lower β-amyloid 42 and higher tau proteins CSF levels than controls. Significantly reduced glucose consumption was observed in the right posterior cingulate cortex and left praecuneus areas in LOEU patients than controls, and this finding correlated with memory impairment. In the longitudinal analysis, a significant decrease in MMSE and an increase in verbal fluency scores were found in LOEU patients. These findings evidence that LOEU patients have a significant cognitive impairment, and alteration of cerebral glucose consumption and CSF AD biomarkers than controls. Moreover, they showed a progressive global cognitive decline at follow-up, although verbal fluency was preserved. Further studies are needed to better understand the pathophysiological aspects of LOEU and its association with AD., (© 2022 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Objective: The aim of our study was to evaluate the diagnostic and prognostic value of Electroencephalogram (EEG), brain Magnetic Resonance Imaging (MRI) and cerebrospinal fluid features, currently representing Creutzfeldt-Jacob Disease (CJD) diagnostic criteria., Methods: A retrospective study on rapidly progressive dementia patients admitted at the Neurology Clinic of the University of Rome "Tor Vergata" between 2015 and 2020 was conducted. We evaluated clinical, EEG, cerebrospinal fluid and neuroradiological findings., Results: Our analysis included 13 patients with probable CJD and 18 patients with non-CJD rapidly progressive dementia. Periodic sharp wave complexes were observed in 7/13 CJD and in 4/18 non-CJD patients (p =.151). The sub-analysis according to the EEG features revealed that CJD patients with earlier periodic sharp wave complexes had a significantly lower average survival time (p =.003), a shorter time to admission (p =.003) and lower levels of cerebrospinal fluid p-tau (p =.008) compared to CJD patients without periodic sharp wave complexes. Finally, they did not show signs of signal alteration on Fluid Attenuated Inversion Recovery images., Conclusions: Despite the lowest diagnostic specificity and sensibility among the CJD criteria, periodic sharp wave complexes could identify a distinctive phenotype hallmarked by a faster evolution, a reduced survival time and specific MRI and cerebrospinal fluid features., Significance: The early presence of the typical EEG pattern may play a prognostic role in CJD., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: Epilepsy treatment during pregnancy is still challenging. The study is aimed at comparing the efficacy and safety of carbamazepine (CBZ), lamotrigine (LTG) and levetiracetam (LEV) monotherapies during pregnancy in women with focal (FE) or generalized (GE) epilepsy., Methods: A multicentre retrospective study was conducted to evaluate seizures frequency and seizure freedom (SF) rate during 3 months before pregnancy, each trimester of gestation and post-partum period in women on monotherapy with CBZ, LTG and LEV., Results: Fifty-seven pregnancies (45 FE, 12 GE) on monotherapy (29 CBZ, 11 LTG, 17 LEV) were included. A significant reduction of seizure frequency was found in the first trimester of pregnancy as compared with that one before pregnancy (p = 0.004), more evident in GE (p = 0.003) and in LEV group (p = 0.004). The SF rate significantly increased in the first trimester in comparison to that one before pregnancy and persisted in the post-partum period in the whole sample (p < 0.001) and in women on LEV (p = 0.004). Besides, 88.57% of SF women before pregnancy remained unchanged during gestation and the post-partum period. One major heart malformation in CBZ and no major malformations in LTG and LEV groups were found., Conclusions: A better clinical outcome during pregnancy emerged since the first trimester in comparison to the before-pregnancy period, mostly evident in women with GE and LEV therapy, reinforcing the hypothesis of a protective role of pregnancy versus seizures. SF before pregnancy represents a significant predictive factor of good clinical outcome during gestation and the post-partum period. Compared to CBZ, LTG and LEV showed a better safety profile., (© 2021. The Author(s).)

Deep Eutectic Solvents (DESs) have been widely used in many fields to exploit their ecofriendly characteristics, from green synthetic procedures to environmentally benign industrial methods. In contrast, their application in emerging solar technologies, where the abundant and clean solar energy is used to properly respond to most important societal needs, is still relatively scarce. This represents a strong limitation since many solar devices make use of polluting or toxic components, thus seriously hampering their eco-friendly nature. Herein, we review the literature, mainly published in the last few years, on the use of DESs in representative solar technologies, from solar plants to last generation photovoltaics, featuring not only their passive role as green solvents, but also their active behavior arising from their peculiar chemical nature. This collection highlights the increasing and valuable role played by DESs in solar technologies, in the fulfillment of green chemistry requirements and for performance enhancement, in particular in terms of long-term temporal stability.

Background: Sleep disorders may cause dysregulation in cerebral glucose metabolism and synaptic functions, as well as alterations in cerebrospinal fluid (CSF) biomarker levels., Objective: This study aimed at measuring sleep, CSF Alzheimer's disease (AD) biomarkers, and cerebral glucose consumption in patients with obstructive sleep apnea syndrome (OSAS) and patients with periodic limb movement disorder (PLMD), compared to controls., Methods: OSAS and PLMD patients underwent 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET), polysomnographic monitoring, and lumbar puncture to quantify CSF levels of amyloid-β42 (Aβ42), total tau, and phosphorylated tau. All patients were compared to controls, who were not affected by sleep or neurodegenerative disorders., Results: Twenty OSAS patients, 12 PLMD patients, and 15 controls were included. Sleep quality and sleep structure were altered in both OSAS and PLMD patients when compared to controls. OSAS and PLMD patients showed lower CSF Aβ42 levels than controls. OSAS patients showed a significant increase in glucose uptake in a wide cluster of temporal-frontal areas and cerebellum, as well as a reduced glucose consumption in temporal-parietal regions compared to controls. PLMD patients showed increased brain glucose consumption in the left parahippocampal gyrus and left caudate than controls., Conclusion: Sleep dysregulation and nocturnal hypoxia present in OSAS patients, more than sleep fragmentation in PLMD patients, were associated with the alteration in CSF and 18F-FDG PET AD biomarkers, namely reduction of CSF Aβ42 levels and cerebral glucose metabolism dysregulation mainly in temporal areas, thus highlighting the possible role of sleep disorders in driving neurodegenerative processes typical of AD pathology.

Dye-Sensitized Photoelectrochemical Cells (DS-PECs) have been emerging as promising devices for efficient solar-induced water splitting. In DS-PECs, dyes and catalysts for water oxidation and/or reduction are typically two separate components, thus limiting charge transfer efficiency. A small number of organometallic dyes have been integrated with a catalyst to form an integrated dye-catalyst dyad for photoanodes, but until now no dyads based on metal-free organic dyes have been reported for photoanodes. We herein report the first example of dyad-sensitized photoanodes in DS-PEC water splitting based on metal-free organic dyes and a Ru catalyst. The di-branched donor-π-acceptor dyes carry a donor carbazole moiety which has been functionalized with two different terminal pyridyl ligands in order to coordinate a benchmark Ru complex as a water oxidation catalyst, affording water oxidation dyads. The two dyads have been fully characterized in their optical and electrochemical properties, and XPS has been used to confirm the presence of the catalyst bonded to the dye anchored to the semiconductor anode. The two dyads have been investigated in DS-PEC, showing an excellent faradaic efficiency (88% average across all cells, with a best cell efficiency of 95%), thus triggering new perspectives for the design of efficient molecular dyads based on metal-free dyes for DS-PEC water splitting., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We experimentally investigate the two-photon absorption cross sections and spectra of eosin and hematoxylin for applications in nonlinear microscopy. The experiments are carried out on pure samples of the two dyes in DI-water solvent with different concentrations, in the typical range employed in standard staining procedures. Nonlinear fluorescence is excited by a line-shaped beam emitted by a Ti:Sapphire mode-locked laser in the wavelength range from 740 to 880 nm and is detected through a microscope setup. The two-photon absorption spectral response is systematically analyzed and discussed. Finally, the staining is applied on biological tissue samples, which are imaged by two-photon microscopy. Our results show that the employed dyes are fully suitable for applications in nonlinear imaging., (© 2020 Wiley-VCH GmbH.)

Perampanel (PER) and brivaracetam (BRV) are third-generation antiseizure medications. The aim of the present retrospective, double-centre study was to compare the effectiveness and tolerability between PER and BRV in adult patients with epilepsy. We reviewed the clinical charts of patients affected by epilepsy, admitted to the Epilepsy Centre at the University Hospital of Rome "Tor Vergata" and the Cardarelli Hospital in Naples, who started BRV or PER as add-on treatment for controlling seizures with a follow-up of 12 months. Seizure freedom, >50% seizure reduction, retention rate, and adverse events reported during follow-up were compared between the two drugs. Moreover, we considered the effects of both drugs in specific subsets of patients: age ≥60 years, male or female, in patients with genetic generalized epilepsy, and considering previous treatment with levetiracetam (LEV). Forty-three patients treated with BRV and 64 patients treated with PER were included in this study and followed at both sites for 12 months. Similar effectiveness was observed between BRV and PER, with similar rates of seizure freedom (30% vs 31%) and >50% seizure reduction (32% vs 34%) during follow-up. Moreover, PER and BRV discontinuation rates, due to ineffectiveness or adverse events, were similar. Groups of patients who started BRV or PER as first add-on treatments were also compared but no differences in effectiveness or tolerability were identified. Lastly, BRV was shown to be more effective in patients who were not previously treated with LEV. This retrospective study reveals comparable effectiveness and tolerability between PER and BRV also when used as first add-on treatments, in patients with epilepsy.

Introduction: Epilepsy has a growing frequency, particularly in the elderly. Several triggers may cause late-onset epilepsy; however, more than 20% of epilepsies, manifesting in the elderly, has an unknown etiology. Although cognition is frequently altered in patients affected by epilepsy, there is a paucity of studies specifically evaluating cognition in patients affected by late-onset epilepsy. The aim of the present study was to assess the cognitive profile of patients affected by late-onset epilepsy with an unknown etiology and followed for 12 months., Methods: Patients affected by diagnosed late-onset epilepsy with unknown etiology were included in this observation. All patients were evaluated at the time of diagnosis (baseline) and at follow-up (12 months later). We distributed patients in subgroups based on seizure type (focal seizures [FS], secondarily generalized seizures [SGS], primarily generalized seizures [GS]) and antiepileptic drug (AED) regimen (mono- vs. polytherapy). Cognition was evaluated through standardized neuropsychological testing., Results: Fifty-eight patients were included in this observation and distributed in three groups: 29 affected by FS, 14 affected by SGS, 15 affected by GS. Forty-five patients were in monotherapy, and 13 in polytherapy. The most frequent treatments were levetiracetam (n = 12), valproic acid (VPA) (n = 9), carbamazepine (n = 9), and oxcarbazepine (n = 7). We documented a significant decrease of Mini-Mental State Examination (MMSE) and memory scores at follow-up in the whole group. Verbal learning decreased exclusively in VPA users., Conclusion: Patients affected by late-onset epilepsy with unknown etiology showed a significant decline of cognition at follow-up, independently from number and efficacy of AEDs received. These results deserve verification in larger longitudinal cohorts., (Copyright © 2019 Elsevier Inc. All rights reserved.)

In this work, the data on the effect of peripheral functionalization of a series of triphenylamine based di-branched dyes used as sensitizers in dye-sensitized solar cells are presented. The effect of different alkyl functionalities on the donor moiety upon the optical and photovoltaics parameters have been investigated in dye-sensitized solar cells (DSSCs) using a 10-μm TiO 2 active layer. The absorption spectra, output efficiency, and incident photon to conversion efficiency of the DSSCs have been collected. The data can be exploited for properly designing efficient, stable, and industrially viable dyes for third generation solar devices.

The use of a hydrophobic eutectic solvent based on dl-menthol and a naturally occurring acid such as acetic acid has been tested as an eco-friendly electrolyte medium in dye-sensitized solar cells. In the presence of a de-aggregating agent and a representative hydrophobic organic photosensitizer, the corresponding devices displayed relatively good power conversion efficiencies in very thin active layers. In particular, the higher cell photovoltage detected in comparison to devices based on toxic and volatile organic compounds may stem from a more efficient interface interaction, as suggested by electrochemical impedance spectroscopy studies showing greater charge recombination resistance and electron lifetime., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The data presented in this article are related to the research article entitled "An unconventional helical push-pull system for solar cells" (Dova et al., 2019). This article provides: a) the cyclic voltammogram plots in solution of helical push-pull sensitizers and the corresponding precursors; b) the visualization of the leading natural transition orbital (NTO) pairs obtained by theoretical calculation of frontiers orbitals; c) J / V curves of dye-sensitized solar cells (DSSC) sensitized by the dyes, without 3a,7a-dihydroxy-5b-cholic acid (CDCA) as co-adsorbent agent; d) 1 H and 13 C NMR spectra of dyes.

Perampanel (PER) is a third generation antiepileptic drug (AED), recently approved as add-on therapy in both focal and generalized seizures. Levetiracetam (LEV) is a second generation AED, widely used in patients with epilepsy because of its favorable safety and efficacy profiles. Perampanel and LEV treatments have been associated with the occurrence of similar adverse events (AEs) (sleepiness, irritability, depression, anxiety, aggressiveness). The aim of the present retrospective single center study was to verify the efficacy and tolerability of PER and LEV used as first add-on therapy in patients with epilepsy affected by secondarily generalized seizures. We collected data from 15 patients treated with PER and 26 patients treated with LEV and followed at our site with follow-up visits at 3, 6, and 12months. This retrospective study documented the comparable efficacy of PER and LEV as first add-on treatments in patients affected by uncontrolled secondarily generalized seizures. However, more patients withdrawn LEV because of AEs compared with PER at the 3- and 12-month follow-up visits. The better tolerability of PER observed in this study could be related to the low therapeutic dose of PER prescribed when it is used as first adjunctive treatment for better controlling secondarily generalized seizures., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Dibranched donor-(π-acceptor)2 dyes, where phenothiazine is the donor core, cyanoacrylic acid is the acceptor/anchoring group, and π is represented by mono- and poly-cyclic simple and fused thiophene derivatives, were tested as photosensitizers in the photocatalytic production of H2 , in combination with a Pt/TiO2 catalyst. The optical and electrochemical properties of the dyes were investigated, showing that careful design of the thiophene-based π spacer afforded enhanced optical properties. In the H2 production over 20 h, the new thiophene-based sensitizers revealed improved stability after longer irradiation times and enhanced performances, in terms of H2 production rates and light-to-fuel efficiencies, after an initial activation period, which were for the first time associated with enhanced stability under photocatalytic production of H2 and the absence of critical dye degradation., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Time-resolved fluorescence and transient absorption experiments uncover a distinct change in the relaxation dynamics of the homo-dimer formed by two 2,5-bis[1-(4-N-methylpyridinium)ethen-2-yl)]-N-methylpyrrole ditriflate (M) units linked by a short alkyl chain when compared to that of the monomer M. Fluorescence decay traces reveal characteristic decay times of 1.1 ns and 210 ps for M and the dimer, respectively. Transient absorption spectra in the spectral range of 425-1050 nm display similar spectral features for both systems, but strongly differ in the characteristic relaxation times gathered from a global fit of the experimental data. To rationalize the data we propose that after excitation of the dimer the energy localizes on one M branch and then decays to a dark state, peculiar only of the dimer. This dark state relaxes to the ground state within 210 ps through non-radiative relaxation. The nature of the dark state is discussed in relation to different possible photophysical processes such as excimer formation and charge transfer between the two M units. Anisotropy decay traces of the probe-beam differential transmittance of M and the dimer fall on complete different time scales as well. The anisotropy decay for M is satisfactorily ascribed to rotational diffusion in DMSO, whereas for the dimer it occurs on a faster time scale and is likely caused by energy-transfer processes between the two monomer M units., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The amplification of Raman signals of the heteroaromatic cation 1-(N-methylpyrid-4-yl)-2-(N-methylpyrrol-2-yl)ethylene ( PEP+ )) bound to Au nanorods (NRs) was investigated at different excitation wavelengths to study the effect of the laser resonance with the absorption band of the PEP+ moiety and with the two plasmon oscillation modes of the NR. Two different PEP+ derivatives, differing in the length of the alkyl chain bearing the anchoring group, were used as target molecules. Raman spectra obtained exciting at 514 or at 785 nm (i.e., exciting the transverse or the longitudinal plasmon band) present a higher intensity than that at 488 nm suggesting a higher Raman amplification when the laser excitation wavelength is resonant with one of the two plasmon modes. Moreover, considering results of Discrete Dipole Approximation (DDA) calculations of the local field generated at the NR surface when either the transverse or the longitudinal plasmon modes are excited, we deduced that the resonance condition of the 514-nm laser excitation with the absorption band of the dye strongly contributes to the amplification of the Raman signal.

The first examples of thiocyanate-free thiophene-substituted Ru(II) cyclometalated complexes, based on thiophene-derived 2-(2,4-difluorophenyl)pyridine ligands, are presented and investigated as photosensitizers in DSCs. Upon thiophene substitution the complexes presented enhanced optical properties compared to the reference dye with no thiophene substitution. DSCs based on the dithienyl-derived dye showed power conversion efficiencies up to 5.7%, more than twice that containing the complex without the thiophene substitution.

A new general synthetic access to carboxylated quaterpyridines (qpy), of interest as ligands for panchromatic dye-sensitized solar cell organometallic sensitizers, is presented. The strategic step is a Suzuki-Miyaura cross-coupling reaction, which has allowed the preparation of a number of representative unsubstituted and alkyl and (hetero)aromatic substituted qpys. To bypass the poor inherent stability of 2-pyridylboronic acid derivatives, we successfully applied N-methyliminodiacetic acid (MIDA) boronates as key reagents, obtaining the qpy ligands in good yields up to (quasi)gram quantities. The structural, spectroscopic (NMR and UV-vis), electrochemical, and electronic characteristics of the qpy have been experimentally and computationally (DFT) investigated. The easy access to the bis-thiocyanato Ru(II) complex of the parent species of the qpy series, through an efficient route which bypasses the use of Sephadex column chromatography, is shown. The bis-thiocyanato Ru(II) complex has been spectroscopically (NMR and UV-vis), electrochemically, and computationally investigated, relating its properties to those of previously reported Ru(II)-qpy complexes.

Ru(II) heteroleptic complexes as photosensitizers for dye-sensitized solar cells (DSCs) are presented. The article outlines design strategies, synthetic routes, optical and photovoltaic properties of ruthenium dyes based on polypyridines as ancillary ligands containing π-conjugated electron-rich heteroaromatic groups. The integration of donor heteroaromatic substituents, typically thiophene-based moieties, strongly improves the optical properties of the sensitizers in terms of bathochromic and hyperchromic shift compared to prototypical dyes N3 and N719. These favorable properties in turn yield DSCs with superior light harvesting abilities, higher external quantum efficiencies, improved device photocurrents, and top-ranked power conversion efficiencies. In combination with excellent stabilities under thermal stress and light soaking, this class of DSC photosensitizer has great potential for practical applications.

The first example of a heteroarylvinylene π-conjugated quaterpyridine Ru(II) sensitizer (N1044) was synthesized and used in dye-sensitized solar cells; the dye has an effective panchromatic absorption band, covering the entire visible spectrum up to the NIR region, and superior electrochemical characteristics (HOMO/LUMO and bandgap energies) with respect to previous representative Ru(II) bi- and quaterpyridine sensitizers. A record IPCE curve ranging from 360 to 920 nm has been measured with a maximum of 65% at 646 nm and still 33% efficiency at 800 nm; this leads to substantially increased photocurrent (19.2 mA cm(-2)) when compared to the prototype N719 Ru(II) sensitizer.

A series of highly efficient and thermally stable second-order nonlinear optical (NLO) dipolar donor-auxiliary donor-acceptor chromophores have been synthesised in which a hydrazono group and a pyrrole ring act as donor and auxiliary donor components, respectively, in combination with different aromatic and heteroaromatic acceptors. The new dyes have been systematically investigated by NMR spectroscopy, absorption spectroscopy, NLO measurements and thermal stability studies. NLO properties have been studied in detail by electro-optical absorption (EOA) and hyper-Rayleigh scattering (HRS) measurements in 1,4-dioxane and DMSO, respectively. The results originating from the two different methods have been compared and analysed in detail. We found that the NLO properties measured by the EOA and HRS methods correlate with each other and converge to reveal the dye with the acceptor 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran as the most efficient system. The unprecedented combination of a strong donor hydrazono group and the auxiliary donor effects of pi-excessive heteroaromatic rings afforded NLO chromophores with very high values (mu(g)beta0(EOA) up to 2038 x 10(-48) esu and beta(HRS) up to 3980 x 10(-30) esu at 1.5 microm).

A novel heteroleptic ruthenium complex carrying a heteroaromatic-4,4'-pi-conjugated 2,2'-bipyridine [Ru(II)LL'(NCS)(2)] (L = 4,4'-bis[(E)-2-(3,4-ethylenedioxythien-2-yl)vinyl]-2,2'-bipyridine, L' = 4,4'-(dicarboxylic acid)-2,2'-bipyridine) was synthesized and used in dye-sensitized solar cells, yielding photovoltaic efficiencies of 9.1% under standard global AM 1.5 sunlight.