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Nanobiosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
What are the two main approaches for using cantilevers in biosensing?By immobilizing a ligand on one side of the cantilever and placing it in contact with a receptor in solution, the cantilever bends in response to a change in surface stress generated by ligand-receptor binding; the greater the binding energy, the greater the bending. A ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bending causes movement of the cantilever tip of the order of 1–100 nm.Furthermore, the resonance frequency of a microcantilever varies sensitively with molecular adsorption. In the dynamic or resonance mode, cantilevers are excited close to their resonance frequency, which is typically in the kHz or even MHz range. When an additional mass is attached to the oscillating cantilever, its resonance frequency changes (adding a mass lowers the resonance frequency). This is not surprising since, at a first approximation, cantilevers behave like a harmonic oscillator, an ideal oscillating spring-mass system.
Monomers, Polymers, and Plastics
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
In coordination polymerization, the bonds are appreciably covalent but with a certain percentage of ionic character. Bonding occurs between a transition metal central ion and the ligand (perhaps an olefin, a diolefin, or carbon monoxide) to form a coordination complex. The complex reacts further with the ligand to be polymerized by an insertion mechanism.
Constitution of a Chemical Reaction and Reaction Balancing
Published in John Andraos, Reaction Green Metrics, 2018
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. In organic synthesis, ligands are associated with structures of organometallic catalysts which contain a central metal ion surrounded by various kinds of functional groups bonded to it.
Biochar application on heavy metal immobilization in unsaturated soil with vegetation: a review
Published in International Journal of Geotechnical Engineering, 2023
Coordination complex is comprised by the binding of the central atom (or ion, collectively referred to as the central atom) and the molecules or ions around it (called ligands) through coordination bonds. Formation of coordination complexes by the functional groups like (C=O) and heavy metal cations could reduce the bioavailable heavy metal in soil and therefore realize the soil remediation. As for the research of Harvey et al. (2011), Cd2+ sorption occurred primarily by two distinct cation-π bonding mechanisms. One was Cd2+-π bonding to soft ligands like C=O, while the other one was Cd2+-π bonding with electron-rich domains on aromatic structures. The functions of these mechanisms to heavy metal sorption could be more than three times that for ion exchange. Therefore, this way could have significant contributions for soil remediation with high efficiency.
Cr2S3(Et2DTC) complex and [Cr2S3-MoS2(Et2DTC)] bilayer thin films: single source stationed fabrication, compositional, optical, microstructural and electrochemical investigation
Published in Environmental Technology, 2021
Shaan Bibi Jaffri, Khuram Shahzad Ahmad, Saba Ifthikhar
Different ions or molecules in the form of functional groups establishing a bond with the central atom of the metal for the formation of coordination complexes are known as ligands in the coordination chemistry. Binding of the ligand with the metal atom is usually by means of the endowment of the electron pair of the ligands (one or more). Different types of ligands have been used for the synthesis of different metallic sulphides. Among different ligands, Dithiocarbamate (DTC) ligands are ranked as the highly significant member of the 1,1-dithiolate class. In the coordination chemistry, the complexes of DTC and metal have acquired a permeating position.