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A series of alkynylplatinum(II) complexes with 2,6-di(pyrid-2-yl)pyrazine ligand has been synthesized and characterized. Interestingly, the complexes have been found to exhibit unprecedented thermochromic behavior with absorption maxima shifting to the longer-wavelength region upon increasing temperature. This phenomenon is significantly different from that in conventional platinum(II) systems, where an elevated temperature typically promotes the dissociation of aggregates and diminishes MMLCT absorptions. Transmission electron microscopy (TEM) and variable-temperature H NMR spectroscopy suggest a thermoresponsive morphological transformation behavior from rods to circular morphologies, driven by the preferential formation of π-π and Pt···Pt interactions over hydrogen bonding interactions upon the disruption of hydrogen bonding at high temperature, as supported by solution-state Fourier transform infrared (FT-IR) spectroscopy together with computational studies. This unusual optical and morphological transformation is rarely observed, as it represents a stark contrast to the deaggregation behavior upon increasing temperature typical of the control and commonly found platinum(II) complexes and organic compounds.
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http://dx.doi.org/10.1021/jacs.5c07413 | DOI Listing |
Proc Natl Acad Sci U S A
September 2025
McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712.
Many soft, tough materials have emerged in recent years, paving the way for advances in wearable electronics, soft robotics, and flexible displays. However, understanding the interfacial fracture behavior of these materials remains a significant challenge, owing to the difficulty of quantifying the respective contributions from viscoelasticity and damage to energy dissipation ahead of cracks. This work aims to address this challenge by labeling a series of polymer networks with fluorogenic mechanophores, subjecting them to T-peel tests at various rates and temperatures, and quantifying their force-induced damage using a confocal microscope.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2025
Department of Biology, Stanford University, Stanford, CA 94305.
Climate change is expected to pose significant threats to public health, particularly vector-borne diseases. Despite dramatic recent increases in dengue that many anecdotally connect with climate change, the effect of anthropogenic climate change on dengue remains poorly quantified. To assess this link, we assembled local-level data on dengue across 21 countries in Asia and the Americas.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2025
Department of Bioengineering, Stanford University, Stanford, CA 94305.
Despite periods of permanent darkness and extensive ice coverage in polar environments, photosynthetic ice diatoms display a remarkable capability of living inside the ice matrix. How these organisms navigate such hostile conditions with limited light and extreme cold remains unknown. Using a custom subzero temperature microscope during an Arctic expedition, we present the finding of motility at record-low temperatures in a Eukaryotic cell.
View Article and Find Full Text PDFEnviron Monit Assess
September 2025
Indira Gandhi Conservation Monitoring Centre, World Wide Fund-India, New Delhi, 110003, India.
Understanding the intricate relationship between land use/land cover (LULC) transformations and land surface temperature (LST) is critical for sustainable urban planning. This study investigates the spatiotemporal dynamics of LULC and LST across Delhi, India, using thermal data from Landsat 7 (2001), Landsat 5 (2011) and Landsat 8 (2021) resampled to 30-m spatial resolution, during the peak summer month of May. The study aims to target three significant aspects: (i) to analyse and present LULC-LST dynamics across Delhi, (ii) to evaluate the implications of LST effects at the district level and (iii) to predict seasonal LST trends in 2041 for North Delhi district using the seasonal auto-regressive integrated moving average (SARIMA) time series model.
View Article and Find Full Text PDFEur J Clin Pharmacol
September 2025
Department of Hospital Pharmacy, Meander Medical Centre, Amersfoort, the Netherlands.
Purpose: This study was designed to analyse the influence of temperature, pH and storage time on unbound fractions of PHT and VPA.
Methods: The influence of ultrafiltration (UF) temperature on measured unbound fractions of PHT and VPA in spiked samples was evaluated in a single laboratory experiment and in data from a national external quality control (EQC) database. The influence of pH adjustment with phosphate buffered saline (PBS) on measured unbound fractions of PHT and VPA was investigated in patient samples.