An elegant method of self-assembly for modification of a TiO(2) surface using coordinating ligands followed by immobilization of variety of sensitizers and a dyad is reported. This highly versatile method, in addition to testing the photoelectrochemical behavior of different zinc tetrapyrroles, allowed the use of fairly complex structures involving more than one donor entity. Utilization of the zinc porphyrin-ferrocene dyad markedly improved the current-voltage performance of the photoelectrochemical cell through an electron transfer-hole migration mechanism. Incident photon-to-current efficiency values up to 37% were obtained for the electrode modified with the dyad, signifying the importance of photocells built on the basis of biomimetic principles for efficient harvesting of solar energy.
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http://dx.doi.org/10.1021/ja9067113 | DOI Listing |
Dalton Trans
January 2025
Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK.
Hexaanionic cyclophosphazenate ligands [(RN)PN] provide versatile platforms for the assembly of multinuclear metal arrays due to their multiple coordination sites and highly flexible ligand core structure. This work investigates the impact of incrementally increasing the steric demand of the ligand periphery on the coordination behavior of ethylzinc arrays. It shows that the increased congestion around the ligand sites is alleviated by progressive condensation with the elimination of diethylzinc.
View Article and Find Full Text PDFACS Catal
January 2025
Institute of Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg, 1, 8093 Zurich, Switzerland.
Buchwald-Hartwig (BH) aminations are crucial for synthesizing arylamine motifs in numerous bioactive molecules and fine chemicals. While homogeneous palladium complexes can be effective catalysts, their high costs and environmental impact motivate the search for alternative approaches. Heterogeneous palladium single-atom catalysts (SAC) offer promising recoverable alternatives in C-C cross-couplings.
View Article and Find Full Text PDFCatal Sci Technol
December 2024
Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern Freiestrasse 3 3012 Bern Switzerland
Even though α-arylation of ketones is attractive for direct C-H functionalization of organic substrates, the method largely relies on phosphine-ligated palladium complexes. Only recently, efforts have focused on developing nitrogen-based ligands as a more sustainable alternative to phosphines, with pyridine-functionalized pyridinium amidate (pyr-PYA) ,'-bidentate ligands displaying good selectivity and activity. Here, we report on a second generation set of catalyst precursors that feature a 5-membered N-heterocycle instead of a pyridine as chelating unit of the PYA ligand to provide less steric congestion for the rate-limiting transmetalation of the enolate.
View Article and Find Full Text PDFR Soc Open Sci
January 2025
Department of Industrial Chemistry, College of Natural and Applied Sciences, Addis Ababa Science and Technology University, PO Box 16417, Addis Ababa, Ethiopia.
The asymmetric Schiff base prepared from ethylenediamine and pyridine-2-carboxaldehyde reacts with Fe(ClO)·6HO to form the Fe(II) complex [FeL](ClO) with L = ,-diethyl-'-(pyridin-2-yl)methylene)ethane-1,2-diamine, where the Fe(III) starting material has been unexpectedly reduced to Fe(II). This complex was characterized by elemental analysis, infrared spectra, single crystal and powder X-ray diffraction measurements, variable temperature DC magnetic measurement and room temperature Mössbauer spectroscopy. The asymmetric ligand L coordinates in a tridentate fashion through its pyridyl, azomethine and amino nitrogen atoms, generating a distorted octahedral geometry around the central metal ion.
View Article and Find Full Text PDFInorg Chem
January 2025
School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
Air-stable single-molecule magnets (SMMs) can be obtained by confining Dy ion in a coordination environment; however, most of the current efforts were focused on modifying the rigidity of the macrocycle ligand. Herein, we attempt to assemble air-stable SMMs based on macrocycles with a replaceable coordination site. By using an in situ 1 + 1 Schiff-base reaction of dialdehyde with diamine, three air-stable SMMs have been obtained in which one of the equatorial coordination sites can be varied from -NH- (for ), -O- (for ), and -NMe- (for ).
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