Copper: Inorganic & Coordination ChemistryBased in part on the article Copper: Inorganic & Coordination Chemistry by Rebecca R. Conry & Kenneth D. Karlin which appeared in the Encyclopedia of Inorganic Chemistry, First Edition .

Abstract

Copper was one of the first metals used widely because the metal is fairly plentiful (among the 25 most abundant elements in the earth's crust) and can be found in its metallic state. In addition, the metal and its alloys have a number of beneficial qualities including ductility, malleability, strength, corrosion resistance, and high thermal and electrical conductivity, combined with an attractive appearance. Copper is also an essential trace nutrient for organisms ranging from bacteria to mammals. Copper exhibits a rich coordination chemistry with complexes known in oxidation states ranging from 0 to +4, although the +2 (cupric) and the +1 (cuprous) oxidation states are by far the most common, with +2 predominating. Compounds of copper have found extensive practical usage, including as catalysts in both homogeneous and heterogeneous reactions, as fungicides, pesticides, and wood preservatives, as pigments for paints and glasses, and in the so‐called high‐temperature superconductors. The coordination numbers and geometries of copper complexes vary with oxidation state. For the spherically symmetric d 10 Cu I ion, the common geometries are two‐coordinate linear, three‐coordinate trigonal planar, and four‐coordinate tetrahedral. Cu I compounds are diamagnetic and colorless, except where color results from charge‐transfer bands or a counterion; these complexes are often fairly readily oxidized to Cu II compounds. The d 9 Cu II ion is usually found in a tetragonal coordination environment, with four short equatorial bonds and another one or two longer axial bonds although complexes with other structures are known, including tetrahedral, square planar, and trigonal bipyramidal geometries. Most of the Cu II compounds are blue or green because of d–d absorptions in the 600 to 900‐nm region; exceptions generally also have charge‐transfer bands tailing into the visible, causing a red or brown appearance. Cu III complexes are typically square planar and diamagnetic.

A microplate screen to estimate metal-binding affinities of metalloproteins

“…56 We attempted to measure the IFE this may cause by titrating Cu 2+ (same preparation and concentrations used in the Cu 2+ →CcSBPII assay) into 10 mM HEPES pH 7.2 without protein and did not observe anything different from titrating the buffer alone (data not shown). Cu + prefers tetrahedral geometries and lower coordination numbers, 57 and our observation that CcSBPII has a low affinity for Zn 2+ , which has a preferred tetrahedral geometry in protein structures, suggests that it is unlikely CcSBPII would specifically bind to Cu + as the major copper species with a KD value (8.54 μM) less than that of Ni 2+ (12.00 μM). Additionally, Cu + requires stabilization through interactions with alkenes and amines.…”

Host-Mediated Copper Stress Is Not Protective against Streptococcus pneumoniae D39 Infection

“…In the absence of GSH, the cellular environment may become less reducing, possibly leading to an increased abundance of Cu(II). As a borderline hard acid, Cu(II) exhibits greater affinity for nitrogen- and oxygen-coordinating ligands ( 57 ) which, when coupled with the highly competitive nature of the Cu(II) ion in biological complexes ( 58 ), is likely to greatly increase the incidence of Cu(II) ions interacting with cytoplasmic proteins and perturbing cellular physiology ( 53 – 55 ). As S. pneumoniae does not appear to possess an alternative thiol pool, these mechanisms provide possible explanations for the severely heightened Cu sensitivity of the Δ copA Δ gshT strain.…”

Excited State Dynamics of a Conformationally Fluxional Copper Coordination Complex

“…7 This strategy critically relies on the fact that Cu(I) and Cu(II) have different coordination properties; the former tend to adopt linear, trigonal, or tetrahedral geometries and bind to highly polarizable ligands, while the latter are stabilized in tetragonal coordination geometries in the presence of weakly polarizable ligands. 8 Initial attempts at leveraging these properties to gate photo-induced CS revealed that the desired photophysical processes were dwarfed by the predominance of unwanted ligand-centered transitions.…”