We report the structural and magnetic properties of two new Mn complex cations in the spin crossover (SCO) [Mn(R-sal323)] series, in lattices with seven different counterions in each case. We investigate the effect on the Mn spin state of appending electron-withdrawing and electron-donating groups on the phenolate donors of the ligand. This was achieved by substitution of the and positions on the phenolate donors with nitro and methoxy substituents in both possible geometric isomeric forms. Using this design paradigm, the [MnL1] () and [MnL2] () complex cations were prepared by complexation of Mn to the hexadentate Schiff base ligands with 3-nitro-5-methoxy-phenolate or 3-methoxy-5-nitro-phenolate substituents, respectively. A clear trend emerges with adoption of the spin triplet form in complexes - with the 3-nitro-5-methoxy-phenolate donors, and spin triplet, spin quintet and thermal SCO in complexes - with the 3-methoxy-5-nitro-phenolate ligand isomer. The outcomes are discussed in terms of geometric and steric factors in the 14 new compounds and by a wider analysis of electronic choices of Mn with related ligands by comparison of bond length and angular distortion data of previously reported analogues in the [Mn(R-sal323)] family. The structural and magnetic data published to date suggest a barrier to switching may exist for high spin forms of Mn in those complexes with the longest bond lengths and highest distortion parameters. A barrier to switching from low spin to high spin is less clear but may operate in the seven [Mn(3-NO-5-OMe-sal323)] complexes - reported here which were all low spin in the solid state at room temperature.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10251414 | PMC |
http://dx.doi.org/10.1021/acs.cgd.2c01284 | DOI Listing |
J Stroke Cerebrovasc Dis
December 2024
Department of Neurology, the Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150000, China.. Electronic address:
Introduction: Branch atheromatous disease (BAD) is prone to early neurological deterioration (END), leading to a poor prognosis. The most common arteries causing END are the lenticulostriate arteries (LSA) and the paramedian pontine arteries (PPA). To gain insight into the characteristics of symptomatic plaques and their association with poor prognosis in patients with BAD, we conducted a prospective study using high-resolution magnetic resonance imaging (HRMRI).
View Article and Find Full Text PDFMagn Reson Imaging
December 2024
Department of Neurology, Yichang Central People's Hospital, The First College of Clinical Medical Science, China Three Gorges University, Yichang, China. Electronic address:
Introduction: More and more evidence suggesting that internal carotid artery stenosis is not only a risk factor for ischemic stroke but also for cognitive impairments. Hypoperfusion and silent micro emboli have been reported as the pathophysiological mechanisms causing cognitive impairment. The effect of carotid artery stenting (CAS) on cognitive function varied from study to study.
View Article and Find Full Text PDFCurr Opin Chem Biol
December 2024
BioEmPiRe Centre for Structural Biological EPR Spectroscopy, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK; Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK. Electronic address:
Pulsed dipolar electron paramagnetic resonance spectroscopy (PDS), combined with site-directed spin-labelling, represents a powerful tool for the investigation of biomacromolecules, emerging as a keystone approach in structural biology. Increasingly, PDS is applied to study highly complex integral membrane protein systems, such as mechanosensitive ion channels, transporters, G-protein coupled receptors, ion pumps, and outer membrane proteins elucidating their dynamics and revealing conformational ensembles. Indeed, PDS offers a platform to study intermediate or lowly-populated states that are otherwise invisible to other modern methods, such as X-ray crystallography, cryo-EM, and hydrogen-deuterium exchange-mass spectrometry.
View Article and Find Full Text PDFEnviron Res
December 2024
School of Nuclear Science and Technology, University of South China, 421000, China.
The copper-based materials were considered as promising catalysts for the activation of peroxydisulfate (PDS), but the study on the CuS-activated PDS under LED illumination and alkaline condition was little reported. In this work, CuS, a simple and readily available heterogeneous catalyst, was employed to enhance the activation of PDS under alkaline condition through LED illumination. The results indicated that under LED illumination, the degradation rate of tetracycline (TC) during the first 15 min was 3.
View Article and Find Full Text PDFJ Magn Reson
December 2024
Bridge12 Magnetic Resonance, 11 Michigan Drive, Natick, MA 01760, USA. Electronic address:
We present a fully automated cryogenic sample insertion and ejection system for use with low-temperature EPR probes. We show how the system can be implemented on a conventional EPR spectrometer and that ejection and insertion is reliably possible at temperatures down to 10 K. Furthermore, we investigate the glass properties of a 0.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!