Carbon–hydrogen bond activation Carbon–hydrogen bond activation Carbon–hydrogen bond functionalization (C–H functionalization) is a type of reaction in which a carbon–hydrogen bond is cleaved and replaced with a carbon-X bond (where X is usually carbon, oxygen, or nitrogen). The term usually implies that a transition metal is involved in the C-H cleavage process. Reactions classified by the term typically involve the hydrocarbon first to react with a metal catalyst to create an organometallic complex in which the hydrocarbon is coordinated to the inner-sphere of a metal, either via an intermediate "alkane or arene complex" or as a transition state leading to a "M−C" intermediate.
Hydrogen darkening loss budget being exceeded. To prevent this, coatings such as carbon are applied to the fiber, and hydrogen capturing gels are used to buffer the fiber, and other proprietary techniques may be used to prevent hydrogen atoms from reaching the glass fiber via the cable sheath. Hydrogen darkening Hydrogen darkening is a physical degradation of the optical properties of glass. Free hydrogen atoms are able to bind to the SiO silica glass compound forming hydroxyl (OH)—a chemical compound that interferes with the passage of light through the glass. The problem is particularly relevant to fiber optic cables—particularly in oil and