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The response of plant species to the variation in abiotic factors affects the regeneration capacity and, consequently, the structure of the forest community. This study aims to describe the structure of the regenerating stratum in a Brazilian montane rainforest and investigate its relationship with environmental and spatial variables along an altitudinal gradient. Data on the height and diameter at soil height of regenerating individuals and environmental variables were collected from 28 sample units, distributed in seven altitudinal sites. To understand the spatial influence on species distribution, spatial variables (MEMs - Moran’s Eigenvector Maps) were created based on geographic coordinates. Phytosociological parameters were calculated by species. Floristic similarity between the altitudinal quota was determined by the Bray-Curtis index (UPGMA), and the species that characterize each group were determined by the Indicator Species Analysis. Redundancy Analysis (RDA) was performed, and generalized linear models were adjusted to verify the influence of environmental and spatial factors on regenerating vegetation. The species Palicourea sessilis had the highest Importance Value in the regenerating community. Two floristic groups were formed: the highest sites (1420 to 1550 m a.s.l.) were floristically more similar to each other (Group 1) than to the sites in the 1112 to 1391 m elevation range (Group 2). Overall, 11 species were indicators of Group 1 and only one of Group 2. Finally, a pattern of species substitution was verified as a function of abiotic factors. The first two axes of the RDA explained 51.02% of the variation in the floristic composition of the regenerating community. Natural regeneration demonstrated environmental preferences, being influenced by luminosity, abundance in adult components, calcium and sodium contents, plant litter accumulation, altitude, and the spatial structure of the environment. Altitude did not seem to influence the pattern of abundance or richness of regenerating species.

Environmental changes caused by edge effects and matrix land use can interfere with plant community resilience and, consequently, alter forest succession. Here, we aimed to (i) investigate whether species composition, density and richness in a forest’s regeneration layer vary in its edge-to-interior gradient and (ii) analyze the relationship between regeneration and local abiotic variables. We conducted the study in the lowland rainforest of the Atlantic Forest biodiversity hotspot at the Córrego Grande Biological Reserve, Espírito Santo state, Brazil. We sampled the regeneration layer in two edge environments with different matrices (forest and road) and the fragmented interior to link vegetation structure with environmental variables. In each environment, we set up 12 plots of 5 × 10 m size and recorded, in each plot, the height and stem base diameter of all living individuals above 50 cm of height and below 2.5 cm of diameter at breast height (1.30 m height). We applied different multivariate analyses to assess the influence of environmental data, such as canopy openness and physical-chemical soil variables. The three environments shared 22 out of the 174 morphospecies recorded, and the forest-side edge had the lowest species richness among all environments. The environmental variables that better explained the distribution of species across the three environments were: canopy openness, soil penetration resistance, zinc, and calcium content. Our results revealed significant environmental differences among the forest edges and the forest interior of the study site, highlighting the relevant role of the forest surrounding matrix for the maintenance of protected remnants.

A chemical reagent to access methyl sulfones has been developed. Its reaction with various bis-nucleophiles leads to the rapid formation of previously unknown heteroaromatic methyl sulfones. Analogous strategy can also be used to construct alkyl-, CHF2-, CF3- and even bicyclo[1.1.1]pentane-containing derivatives. These compounds have been demonstrated to have a high potential for use in medicinal chemistry and coordination chemistry. Methyl sulfone is a standard polar substituent used in chemistry and can be found in different agro chemicals or drugs but due to lack of convenient and efficient chemical approaches to them, heteroaromatic methyl sulfones are less investigated. Here the authors report a reagent to access previously unknown heteroaromatic methyl sulfones. [ABSTRACT FROM AUTHOR]

Fluorescent organotin compounds are useful in sensing, optoelectronic devices, and in vitro bioimaging. Although in vitro fluorescence bioimaging shows low resolution at room temperature, a better resolution is possible at cryotemperatures. Therefore, the search for new cryoluminescent materials with potential application in high-resolution fluorescence bioimaging remains a great challenge. Herein, we report the cryoluminescence properties of two fluorescent bis-organotin compounds, namely, BisNTHySnBu2 (5) and BisNTHySnPh2 (6), synthesized via microwave irradiation. All compounds were fully characterized using 1H, 13C, and 119Sn NMR spectroscopy, Raman spectroscopy, IR spectroscopy, and HR-MS. The 119Sn δ and 3J(1H,119Sn) of 5 and 6 indicate that two Sn-ligands are chemically and electronically equivalent, as confirmed by cyclic voltammetry. The crystal structure of 6 showed pentacoordinate tin atoms with skeleton ligands. The study of self-assembled monolayers of both Sn-complexes via STM microscopy revealed a similar supramolecular packing in lamella-like patterns, adopting a face-on arrangement, where molecules stay flat lying on HOPG in accordance with the height profile of closely packed monolayers on graphite of about 0.33 nm thickness. However, only the Sn complex 6, which bears phenyls, covers large surface areas. The photophysical properties of bis-organotin compounds were also investigated in solution (room and low temperatures) and in the solid state. Good luminescence properties in solutions with fluorescence quantum yields (Φ) of approximately 35% and 50% were found. Despite this, Φ is quenched in the solid state because of aggregation, as supported by solvent/non solvent fluorescence studies, which is in agreement with STM and AFM investigation. [ABSTRACT FROM AUTHOR]

Phenanthroline-based ligands with bulky aryl groups flanking the metal binding pocket enabled the synthesis and detailed investigation of ethylene complexes of copper(I), silver(I), and gold(I), including structural data of [{2,9-bis(2,4,6-triisopropylphenyl)-1,10-phenanthroline}M(C2H4)][SbF6] (M = Cu, Ag, Au), Additionally, a related copper(I)-ethylene complex with a highly fluorinated ligand is also reported. Gold(I) affects the ethylene moiety significantly as evident from the notable upfield coordination shifts of ethylene carbon signals in the NMR and lengthening of the ethylene C＝C bond length. Silver(I) forms the weakest bond with ethylene in this series of isoleptic, group 11 metal-ethylene complexes. Preliminary catalytic investigations underscore the potential of copper complexes, particularly those with weakly coordinating supporting ligands, as effective catalysts for C(sp3)–H functionalization through trifluoromethyl carbene insertion. [ABSTRACT FROM AUTHOR]

Charged multivesicular body protein 1A (CHMP1A; also known as chromatin-modifying protein 1A) is a member of the ESCRT-III (endosomal sorting complex required for transport-III) complex but is also suggested to localize to the nuclear matrix and regulate c

Gold coordination chemistry and catalysis involving unsaturated hydrocarbons such as olefins have experienced a remarkable growth during the last few decades. Despite the importance, isolable and well-characterized molecules with ethylene, the simplest and the most widely produced olefin, on gold are still limited. This review aims to cover features of, and strategies utilized to stabilize, gold–ethylene complexes and their diverse use in chemical transformations and homogeneous catalytic processes. Isolable and well-authenticated gold–ethylene complexes are important not only for structural, spectroscopic, and bonding studies but also as models for likely intermediates in gold mediated reactions of alkenes and gold–alkene species observed in the gas phase. There has also been development on AuI/III catalytic cycles. Nitrogen based ligands have been the most widely utilized ligand supports thus far for the successful stabilization of gold–ethylene adducts. Gold has a bright future in olefin chemistry and with ethylene. [ABSTRACT FROM AUTHOR]

In the course of studying Diels–Alder reactions of 4-vinylimidazoles with N-phenylmaleimide, it was discovered that they engage in cycloaddition at room temperature to give high yields of the initial cycloadduct as a single stereoisomer. In certain cases, the product precipitated out of the reaction mixture and could be isolated by simple filtration, thereby avoiding issues with aromatization observed during chromatographic purification. Given these results, intramolecular variants using doubly activated dienophiles were also investigated at room temperature. Amides underwent cycloaddition at room temperature in modest yields, but the initial adducts were not isolable with Nimid-benzyl-protected systems. Attempts to extend these results to the corresponding esters and hydroxamate were less successful with these substrates only undergoing cycloaddition at elevated temperatures in lower yields. Density functional theory calculations were performed to evaluate the putative transition states for both the inter- and intramolecular variants to rationalize experimental observations. [ABSTRACT FROM AUTHOR]

A unique four‐coordinate, classical gold(I)‐carbonyl complex with substantial backdonation from gold has been isolated by using a B‐methylated and fluorinated tris(pyridyl)borate chelator. Its lighter silver(I) and copper(I) analogs enabled a study of trends in the coinage‐metal family. The B‐arylated ligand version also afforded a gold–carbon monoxide complex that displays a notably low C−O stretch value, but with trigonal planar geometry at the gold. A computational analysis shows that the AuI−CO bonds of these tris(pyridyl)borate ligand‐supported molecules consist of electrostatic attraction, OC→Au σ‐donation, and very significant Au→CO π‐back‐bonding components. The latter is responsible for the observed C−O stretching frequencies, which are lower than in free CO. [ABSTRACT FROM AUTHOR]

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