Changes occur from mixing chemical compounds: electrovalent bonds and covalent bonds

Covalent Bonds

Covalent palladium-zinc bonds and their reactivity.

Photolysis of ((F)PNP)Pd-Et in the presence of Et(2)Zn leads to the formation of ((F)PNP)Pd-Zn-Pd(PNP(F)), the first example of a compound with a covalent Pd-Zn bond.

Functional systems with orthogonal dynamic covalent bonds.

This review summarizes the use of orthogonal dynamic covalent bonds to build functional systems. Dynamic covalent bonds are unique because of their dual nature. They can be as labile as non-covalent interactions or as permanent as covalent bonds, depending on conditions. Examples from nature, reaching from the role of disulfides in protein folding to thioester exchange in polyketide biosynthesi...

Superconductivity of MgB2: covalent bonds driven metallic.

A series of calculations on MgB2 and related isoelectronic systems indicates that the layer of Mg2+ ions lowers the nonbonding B pi ( p(z)) bands relative to the bonding sigma ( sp(x)p(y)) bands compared to graphite, causing sigma-->pi charge transfer and sigma band doping of 0.13 holes/cell. Because of their two dimensionality the sigma bands contribute strongly to the Fermi level density of s...

Mechanochemistry: the mechanical activation of covalent bonds.

Regarding the activation of chemical reactions, today’s chemist is used to thinking in terms of thermochemistry, electrochemistry, and photochemistry, which is reflected in the organization and content of the standard physical chemistry textbooks. The fourth way of chemical activation, mechanochemistry, is usually less well-known. The purpose of the present review is to give a survey of the cla...