Metal-Metal Bond in the Light of Pauling's Rules.

Molecules

CNR-SCITEC Istituto di Scienze e Tecnologie Chimiche "Giulio Natta", sezione di via Golgi, via Golgi 19, I-20133 Milano, Italy.

Published: January 2021

About 70 years ago, in the framework of his theory of chemical bonding, Pauling proposed an empirical correlation between the bond valences (or effective bond orders (BOs)) and the bond lengths. Till now, this simple correlation, basic in the bond valence model (BVM), is widely used in crystal chemistry, but it was considered irrelevant for metal-metal bonds. An extensive analysis of the quantum chemistry data computed in the last years confirms very well the validity of Pauling's correlation for both localized and delocalized interactions. This paper briefly summarizes advances in the application of the BVM for compounds with TM-TM bonds (TM = transition metal) and provides further convincing examples. In particular, the BVM model allows for very simple but precise calculations of the effective BOs of the TM-TM interactions. Based on the comparison between formal and effective BOs, we can easily describe steric and electrostatic effects. A possible influence of these effects on materials stability is discussed.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7827070PMC
http://dx.doi.org/10.3390/molecules26020304DOI Listing

Publication Analysis

Top Keywords

effective bos
8
metal-metal bond
4
bond light
4
light pauling's
4
pauling's rules
4
rules years
4
years ago
4
ago framework
4
framework theory
4
theory chemical
4

Similar Publications

Comparison of optimization algorithms for automated method development of gradient profiles.

J Chromatogr A

December 2024

Analytical Chemistry Group, Van 't Hoff Institute for Molecular Sciences, Science Park 904, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, the Netherlands; AI4Science Lab, Informatics Institute, University of Amsterdam, Science Park 904, the Netherlands. Electronic address:

Optimization algorithms play an important role in method development workflows for gradient elution liquid chromatography. Their effectiveness has not been evaluated for chromatographic method development using standardized comparisons across factors such as sample complexity, chromatographic response functions (CRFs), gradient complexity, and application type. This study compares six optimization algorithms - Bayesian optimization (BO), differential evolution (DE), a genetic algorithm (GA), covariance-matrix adaptation evolution strategy (CMA-ES), random search, and grid search - for the development of gradient elution LC methods.

View Article and Find Full Text PDF

Background: Biological control in integrated pest management (IPM) often overlooked avian predators until the emergence of the ecosystem services approach. Birds are now recognized as key regulators of pest populations in agroforestry landscapes due to their high mobility. The invasive yellow-legged hornet, introduced into Europe in 2004, threatens agriculture, beekeeping and native pollinators.

View Article and Find Full Text PDF

Micro-nanoscale polystyrene co-exposure impacts the uptake and translocation of arsenic and boscalid by lettuce (Lactuca sativa).

NanoImpact

January 2025

Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, CT, USA.

The influence of micro-nanoplastics (MNPs) on the fate and effects of other pollutants present in the environment is largely unknown. This study evaluated if the root exposure to MNPs (polystyrene, PS; 20 or 1000 nm) had an impact on the accumulation of arsenic and boscalid (As and Bos) in lettuce (Lactuca sativa). Under hydroponic conditions, plants were co-exposed to MNPs at 10 or 50 mg/L, and to 1 mg/L of each environmental pollutant (EP).

View Article and Find Full Text PDF

Objectives: In the intensive care unit (ICU), antibiotics are often given longer than recommended in guidelines. A better understanding of the factors influencing antibiotic therapy duration is needed to develop improvement strategies to effectively address these drivers of excessive duration. This study aimed to explore the determinants of adherence to recommended antibiotic therapy durations among healthcare professionals involved in antibiotic decision-making within the ICU, focusing on multidisciplinary meetings (MDMs).

View Article and Find Full Text PDF

A simple HPLC-UV method for monitoring therapeutic adherence in pulmonary arterial hypertension.

J Chromatogr B Analyt Technol Biomed Life Sci

December 2024

Pulmonary Circulation Centre, Department of Cardiac and Vascular Diseases, Jagiellonian University Medical College, Krakow, Poland; Department of Cardiac and Vascular Diseases, St. John Paul II Hospital, Krakow, Poland.

A considerable percentage of ineffective treatment in pulmonary arterial hypertension (PAH) may be related to subtherapeutic dosage or non-adherence. The aim of the study was to develop a simple analytical method suitable for plasma determination of selected drugs: riociguat (RIO), bosentan (BOS) and macitentan (MAC) administered to PAH patients. An isocratic HPLC-UV system (Spectra Physics - Shimadzu) with a manual injector (50 μL loop) was applied.

View Article and Find Full Text PDF

Want 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!