The crystal structure of Cs2BaTa6Br15O3 has been elucidated by using synchrotron X-ray powder diffraction and absorption experiments. It is built from edge-bridged octahedral [(Ta6Bri9Oi3)Bra6]4− cluster units with a singular poor metallic electron (ME) count equal to thirteen. This leads to a paramagnetic behaviour related to one unpaired electron. The arrangement of the Ta6 clusters is similar to that of Cs2LaTa6Br15O3 exhibiting 14-MEs per [(Ta6Bri9Oi3)Bra6]5− motif. The poorer electron-count cluster presents longer metal–metal distances as foreseen according to the electronic structure of edge-bridged hexanuclear cluster. Density functional theory (DFT) calculations on molecular models were used to rationalise the structural properties of 13- and 14-ME clusters. Periodic DFT calculations demonstrate that the electronic structure of these solid-state compounds is related to those of the discrete octahedral units. Oxygen–barium interactions seem to prevent the geometry of the octahedral cluster to strongly distort, allowing stabilisation of this unprecedented electron-poor Ta6 cluster in the solid state.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/chem.201300777 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Domino Conjugate Addition-1,4-Aryl Migration for the Synthesis of α,β-Difunctionalized Amides.
JACS Au
July 2024
Institute of Organic Chemistry, University of Vienna, Währinger Straße 38, 1090 Vienna, Austria.
A domino difunctionalization of sulfonyl(acryl)imides to form β-substituted α-aryl amides is reported. This transformation involves a 1,4-addition followed by a polar Truce-Smiles rearrangement process, entropically driven by release of SO. A wide range of carbon- and heteroatom-based nucleophiles and sulfonyl imides were employed, allowing rapid access to highly functionalized amides.
View Article and Find Full Text PDFPalladium-Catalyzed Inverse and Normal Dehydrogenative Aza-Morita-Baylis-Hillman Reactions with γ,δ-Unsaturated Compounds.
Angew Chem Int Ed Engl
June 2023
Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China.
σ-Lewis base-catalyzed regio- and enantioselective aza-Morita-Baylis-Hillman (MBH) reaction of α,β,γ,δ-unsaturated systems remains a challenge due to the intrinsic covalent activation mode. Here we demonstrate that a Pd complex can mediate the dehydrogenative reaction of γ,δ-unsaturated compounds to give corresponding electron-poor dienes, which further undergo δ-regioselective umpolung Friedel-Crafts-type addition to imines via auto-tandem Pd -π-Lewis base catalysis. After β-H elimination of in situ formed Pd -complexes, unprecedented and chemically inverse aza-MBH-type adducts are finally furnished with fair to outstanding enantioselectivity, and a diversity of functional groups and both ketimine and aldimine acceptors can be well tolerated.
View Article and Find Full Text PDFChemodivergent Organolanthanide-Catalyzed C-H α-Mono-Borylation of Pyridines.
J Am Chem Soc
September 2022
Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States.
Chemodivergent synthetic methodologies enable the efficient introduction of structural diversity into high-value organic products via simple chemical alterations. In this regard, C-H activation and functionalization of pyridinoid azines are important transformations in the synthesis of many natural products, pharmaceuticals, and functional materials. Reflecting on azinyl nitrogen lone-pair steric repulsion, its tendency to irreversibly coordinate metal ion catalysts, and the electron deficiency of pyridine, C-H functionalization at the important α-position remains challenging.
View Article and Find Full Text PDFIdentification of an electron poor trifluoroacetophenone allows the formation of uniquely stable hemiketals from prochiral oxetanols. When exposed to a cobalt(ii) catalyst, efficient ring-opening to densely functionalized dioxolanes is observed. Mechanistic studies suggest an unprecedented redox process between the cobalt(ii) catalyst and the hemiketal that initiates the oxetane-opening.
View Article and Find Full Text PDFAn unprecedented pyridine-based dinuclear mixed-valent Re oxo-bridged complex: a solvatochromic and AIE-active probe for nanomolar detection of picric acid and trinitrotoluene.
Dalton Trans
July 2021
Department of Chemistry, BITS-Pilani Hyderabad Campus, Hyderabad-500078, India.
This paper describes the synthesis of an unprecedented oxo-bridged rheniumI/VII (Re) complex by treating Re2(CO)10 with a pyridyl-linked anthracene-based twisted π-conjugated ligand. The molecular structures of both the ligand and the complex are determined by analyzing IR, NMR, and HR-MS spectra and unequivocally determined using single-crystal X-ray diffraction studies. Unlike previous observations, the complexation occurs uniquely to yield an unprecedented oxo-bridged ReI/VII complex.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!