An FT-IR spectroscopic study of the crystalline and columnar liquid-crystalline phases of copper (II) carboxylates

The FT-IR spectra of a series of anhydrous copper (II) carboxylates of general formula Cu2[CH3(CH2)nCOO]4 (n = 4–8, 10, 12, 14, 16) show notable changes with the phase transition from the crystalline to the columnar liquid-crystalline phase. These changes indicate that the coordination of the carboxylate groups to the bimetallic centre changes from bridging bidentate to chelating bidentate, which in turn is induced by the conformational disordering in the carbon chains

An FT-IR spectroscopic study of the crystalline and columnar liquid-crystalline phases of copper (II) carboxylates

The FT-IR spectra of a series of anhydrous copper (II) carboxylates of general formula Cu2[CH3(CH2)nCOO]4 (n = 4–8, 10, 12, 14, 16) show notable changes with the phase transition from the crystalline to the columnar liquid-crystalline phase. These changes indicate that the coordination of the carboxylate groups to the bimetallic centre changes from bridging bidentate to chelating bidentate, which in turn is induced by the conformational disordering in the carbon chains

A concerted SCF-MO ab initio and vibrational spectroscopic study of the conformational isomerism in 2-aminoethanol

Conformational isomerism in isolated and liquid 2-aminoethanol was investigated by a concerted molecular orbital and vibrational spectroscopic approach. The molecular structures, relative energies, dipole moments and vibrational spectra (both infrared and Raman) of the various possible conformers of the studied compound were calculated, using the extended 6-31G* basis set at the HF-SCF ab initio level of theory. The theoretical results were then used to interpret infrared and Raman data obtained under different experimental conditions. It was found that none of the most populated conformational states existing in the pure liquid (where intermolecular H-bonding occurs extensively)-the gGt and tTt conformers - , correspond to the conformational ground state for the isolated 2-aminoethanol molecule - the intramolecularly H-bonded g'Gg' conformer.http://www.sciencedirect.com/science/article/B6TGS-40D60M5-3T/1/fb782f2e3c62f7deac60dcc181407c9

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora