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In the last year [1], Angiolini and co-workers have synthesized and investigated methacrylic polymers bearing in the side chain the chiral cyclic (S)-3-hydroxypyrrolidine moiety interposed between the main chain and the trans-azoaromatic chromophore, substituted or not in the 4’ position by an electron-withdrawing group. In these materials, the presence of a rigid chiral moiety of one prevailing absolute configuration favours the establishment of a chiral conformation of one prevailing helical handedness, at least within chain segments of the macromolecules, which can be observed by circular dichroism (CD). The simultaneous presence of the azoaromatic and chiral functionalities allows the polymers to display both the properties typical of dissymmetric systems (optical activity, exciton splitting of dichroic absorptions), as well as the features typical of photochromic materials (photorefractivity, photoresponsiveness, NLO properties). The first part of this research was to synthesize analogue homopolymers and copolymers based on bisazoaromatic moiety and compare their properties to those of the above mentioned analogue derivatives bearing only one azoaromatic chromophore in the side chain. We focused also the attention on the effects induced on the thermal and chiroptical behaviours by the insertion of particulars achiral comonomers characterized by different side-chain mobility and grown hindrance (MMA, tert-BMA and TrMA). On the other hand carbazole containing polymers [2] have attracted much attention because of their unique features. The use of these materials in advanced micro- and nanotechnologies spreads in many different applications such as photoconductive and photorefractive polymers, electroluminescent devices, programmable optical interconnections, data storage, chemical photoreceptors, NLO, surface relief gratings, blue emitting materials and holographic memory. The second part of the work was focused on the synthesis and the characterization polymeric derivatives bearing in the side chain carbazole or phenylcarbazole moieties linked to the (S)- 2-hydroxy succinimide or the (S)-3-hydroxy pyrrolidinyl ring as chiral groups covalently linked to the main chain through ester bonds. The last objective of this research was to design, synthesize, and characterize multifunctional methacrylic homopolymers and copolymers bearing three distinct functional groups (i.e. azoaromatic, carbazole and chiral group of one single configuration) directly linked in the side chain. This polymeric derivatives could be of potential interest for several advanced application fields, such as optical storage, waveguides, chiroptical switches, chemical photoreceptors, NLO, surface relief gratings, photoconductive materials, etc.

There is a considerable interest in the synthesis and characterization of polymers containing azoaromatic moieties due to their unique optical properties[1]. These materials can be used in advanced micro- and nanotechnologies such as optical data storage[2], nonlinear optical materials[3], holographic memories[4], chiroptical switches[5], surface relief gratings[6], inscription of channel waveguides[7], etc. Since the discovery of the photorefractive effect in organic polymers[8], carbazole containing polymers[9] have also attracted much attention because of their photoconductivity. Multicomponent polymers with structural units containing both photoconductive and electrooptic functionalities in the side-chain can be regarded as suitable materials for photorefractive applications[10]. On the other hand, an intense interest has currently arisen toward investigations dealing with the amplification of chirality of polymeric materials, in solution as well as in the solid state[11]. In this context, a new optically active photochromic polymethacrylate containing the azocarbazole moiety, deriving from the chiral monomer (S)-(4-cyanophenyl)-[3-[9-[2-(2-methacryloyloxypropanoyloxy) ethyl]carbazolyl]]diazene [(S)-MLECA] [12] has been prepared and fully characterized with the aim to obtain a multifunctional material which can be considered at the same time as a photonic material for NLO and optical storage, for chiroptical switches, and for photorefractive and photoconductive applications.

Carbazole has attracted considerable interest as building block in material science for its well known hole-transporting and electroluminescence properties [1]. Since the discovery of the photoconductive character of poly(N-vinylcarbazole) (PVK), carbazole containing polymers [2] have attracted much attention because of their unique features. The use of these material in advanced micro- and nanotechnologies spreads in many different applications such as photoconductive polymers, electroluminescent devices, programmable optical interconnection, data storage, chemical photoreceptors, NLO, surface relief gratings, blue emitting materials, holographic memory. On the other hand, an intense interest has currently arisen toward investigations dealing with the amplification of chirality of polymeric materials, in solution as well as in the solid state [3]. Two novel optically active polymethacrylates bearing in the side chain a chiral group of one prevailing absolute configuration linked in 3 position to the carbazole chromophore, deriving from the chiral monomers (S)-(−)-methacryloyl-2-oxy-N-[3-(9-ethylcarbazole)]-pyrrolidine [(S)-(−)-MECP] and (S)-(−)-methacryloyl-2-oxy-N-[3-(9-ethylcarbazole)]-succinimide [(S)-(+)-MECSI] have been prepared and characterized with the aim to improve the conformational order of the macromolecules and investigate the influence of the intrinsic macromolecular chirality on their photoconductive and photorefractive properties. Spectroscopic, thermal and chiroptical characterizations indicate the occurrence of dipolar interactions between side chain moieties and the presence of an ordered chiral conformations, at least for chain segments of the macromolecules, that influence their photoconductive properties. [1] J.V. Grazuleviciusa, P. Strohrieglb, J. Pielichowskic, K. Pielichowski, Prog. Polym. Sci. 28 (2003) 1297–1353 [2] K. Meerholz, B. Volodin, B. Sandalphon, N. Kippelen, N. Peyghambarian, Nature 1994, 371, 497 [3] M.M. Green, N.C. Peterson, T. Sato, A. Teramoto, R. Cook, S. Lifson, Science, 1995, 268, 1860

There is a considerable interest in the synthesis and characterization of multicomponent polymers with structural units containing both photoconductive (carbazole) and electrooptic (azoaromatic moieties) functionalities in the side-chain due to their unique optical properties. These materials can be used in advanced technologies such as optical data storage, nonlinear optical materials, holographic memories, chiroptical switches, surface relief gratings, inscription of channel waveguides, etc. On the other hand, an intense interest has currently arisen toward investigations dealing with the amplification of chirality of polymeric materials, in solution as well as in the solid state. To our knowledge, multifunctional polymers bearing three functional groups directly linked to the side chain (i. e. azoaromatic, carbazole and chiral group of one single configuration) have not yet been reported and would be of special interest for several advanced application fields, such as optical storage, waveguides, chiroptical switches, chemical photoreceptors, NLO, surface relief gratings, photoconductive materials, etc. In this context, we have prepared and fully characterized a new optically active photochromic polymethacrylate containing the azocarbazole moiety, poly[(S)-(4-cyanophenyl)-[3-[9-[2-(2-methacryloyloxypropanoyloxy) ethyl]carbazolyl]]diazene] , poly[(S)-MLECA], with the aim to obtain a multifunctional material. The polymer displays both the properties typical of dissymmetric systems (optical activity, chiroptical switching), as well as the features of photochromic (photoinduced birefringence, linear dichroism, NLO and surface relief grating) and electrooptic (photoconductive and photorefractive) materials. The observed properties appear of interest for a potential use of these materials in nanoscale technologies for all-optical manipulation of informations and in optoelectronics.

Lignocellulosic biomass, ranging from softwood to agriculture and forestry wastes, represents the most abundant resource for modern biorefinery. In the course of the last years, we have witnessed the rise of ‘reductive catalytic fractionation’ processes of lignocellulosics in which priority attention is given to lignin that is ‘first’ converted into aromatic feedstocks. This opinion outlines recent advances in the reductive valorization of lignocellulosic biomass via lignin-first biorefinery approach, with particular emphasis on the fundamental catalytic reactions involved in the extraction and depolymerization of lignin and in the stabilization of the obtained phenolic units. Finally, a brief overview on the further transformations of lignin-derived monolignols and phenolics into value-added chemicals, fuels, polymeric materials, and active pharmaceutical ingredients is presented.

The use of lignocellulosic biomasses for the production of renewable hydrogen is surely among the hot-topic research tasks. In this review, we report on the recent advances in the catalytic conversion of cellulose and its derived C6-C5 sugars (glucose, fructose, and xylose) and polyols (sorbitol and xylitol) into hydrogen via aqueous phase reforming (APR) reactions. The APR processes are considered to be new sustainable catalytic routes for converting the carbohydrate fraction of biomasses into hydrogen at milder reaction conditions if compared with the traditional reforming reactions. Particular emphasis is given to the development of new and active catalysts and to the optimization of reaction conditions that aimed to maximize hydrogen production with a low concentration of CO avoiding, at the same time, the formation of alkanes.