We have studied the photophysics of tetrafurylethene, an aggregation-induced emission luminogen with exceptionally short intramolecular O-O distances of 2.80 Å and a significant red-shifted morphochromism (27 nm) when going from the aggregate to the crystal. The short O-O distances, which are substantially smaller than the sum of the van der Waals radii (3.04 Å), are due to the fact that the oxygen atoms act as an electronic bridge connecting the furan rings on opposite ends of the central double bond, giving rise to a circular delocalization of the π-electron density across the rings. In the excited state the O-O distance is further reduced to 2.70 Å; the increased O-O interaction causes a narrowing of the HOMO-LUMO gap, resulting in the red morphochromism of the emission. Our results show the structural origin of the red-shifted emission lies in close O-O contacts, paving the way for understanding the clusteroluminescence of oxygen-rich non-conjugated systems that emit visible light.
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http://dx.doi.org/10.1002/anie.201908573 | DOI Listing |
J Am Chem Soc
January 2025
Université de Caen Normandie, ENSICAEN, CNRS, LCS, 14000 Caen, France.
Germanium is known to occupy tetrahedral sites by substituting silicon in germanosilicate zeolites. In this study, we present pioneering findings regarding the synthesis of zeolites with an MFI structure (GeMFI) incorporating a high germanium amount (16% Ge). Remarkably, the germanium atoms feature a slight electron deficiency with respect to GeO, and the typical coordination number of 4, as usually reported for the germanosilicate zeolites, is exceeded, giving rise to Ge dimers in a double-bridge configuration.
View Article and Find Full Text PDFLangmuir
January 2025
Centre for Energy (M473), The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
The mechanisms of NO reduction by CO over nitrogen-doped graphene (N-graphene)-supported single-atom Ni catalysts in the presence of O, HO, CO, and SO have been studied via density functional theory (DFT) modeling. The catalyst is represented by a single Ni atom bonded to four N atoms on N-graphene. Several alternative reaction pathways, including adsorption of NO on the Ni site, direct reduction of NO by CO, decomposition of NO to NO followed by reduction of NO to N, formation of active oxygen radical O*, and reduction of O* by CO, were hypothesized and the energy barrier corresponding to each of the reaction steps was calculated using DFT.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Nanjing University of Aeronautics and Astronautics, College of Materials Science and Technology, No. 169 Sheng Tai West Road, Jiangning District, Nanjing, Jiangsu, China, 211106, Nanjing, CHINA.
Transition metal-based catalysts with high efficiency and stability for overall water splitting (OWS) offer significant potential for reducing green hydrogen production costs. Utilizing sputtering deposition technology, we propose a deposition-diffusion strategy to fabricate heterojunction coatings composed of ultrafine FeCoNi-C-N transition metal interstitial solid solution (TMISS) nanocrystals and amorphous nitrided carbon (NC) on the pre-deposited NC micro column arrays. The diffusion of C and N atoms results in the formation of uniformly distributed TMISS nanocrystals, with an average diameter of ~1.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, The University of Hong Kong, Hong Kong Island 000000, Hong Kong SAR, China.
Methanol (ME) is a liquid hydrogen carrier, ideal for on-site-on-demand H generation, avoiding its costly and risky distribution issues, but this "ME-to-H" electric conversion suffers from high voltage (energy consumption) and competitive oxygen evolution reaction. Herein, we demonstrate that a synergistic cofunctional PtPd/(Ni,Co)(OH) catalyst with Pt single atoms (Pt) and Pd nanoclusters (Pd) anchored on OH-vacancy(V)-rich (Ni,Co)(OH) nanoparticles create synergistic triadic active sites, allowing for methanol-enhanced low-voltage H generation. For MOR, OH* is preferentially adsorbed on Pd and then interacts with the intermediates (such as *CHO or *CHOOH) adsorbed favorably on neighboring Pt with the assistance of hydrogen bonding from the surface hydrogen of (Ni,Co)(OH).
View Article and Find Full Text PDFInorg Chem
January 2025
MOE Key Laboratory of Cluster Science, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, China.
A novel antimonotungstate (AT)-based heterometallic framework {[Er(HO)][Fe(Hpdc)(B-β-SbWO)]}·50HO (, Hpdc = pyridine-2,5-dicarboxylic acid) was obtained through a synergistic strategy of in situ-generated transition-metal-encapsulated polyoxometalate (POM) building units and the substitution reaction. Its structural unit is composed of a tetra-Fe-substituted Krebs-type [Fe(Hpdc)(B-β-SbWO)] subunit and two [Er(HO)] cations. This subunit can be regarded as a product of carboxylic oxygen atoms of Hpdc ligands replacing active water ligands in the [Fe(HO)(B-β-SbWO)] species.
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