Search results
Results from the WOW.Com Content Network
Pyridine is colorless, but older or impure samples can appear yellow, due to the formation of extended, unsaturated polymeric chains, which show significant electrical conductivity. [page needed] [17] The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins.
Pyridine-N-oxide is the heterocyclic compound with the formula C 5 H 5 NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine . It was originally prepared using peroxyacids as the oxidising agent.
The Chichibabin reaction (pronounced ' (chē')-chē-bā-bēn) is a method for producing 2-aminopyridine derivatives by the reaction of pyridine with sodium amide. It was reported by Aleksei Chichibabin in 1914. [1] The following is the overall form of the general reaction:
4-Dimethylaminopyridine (DMAP) is a derivative of pyridine with the chemical formula (CH 3) 2 NC 5 H 4 N. This white solid is of interest because it is more basic than pyridine , owing to the resonance stabilisation from the NMe 2 substituent.
In chemistry, the mesomeric effect (or resonance effect) is a property of substituents or functional groups in a chemical compound. It is defined as the polarity produced in the molecule by the interaction of two pi bonds or between a pi bond and lone pair of electrons present on an adjacent atom. [ 1 ]
When , and are called the overlap and resonance (or exchange) integrals, respectively, while is called the Coulomb integral, and = simply expresses the fact that the are normalized. The n × n matrices [ S i j ] {\displaystyle [S_{ij}]} and [ H i j ] {\displaystyle [H_{ij}]} are known as the overlap and Hamiltonian matrices , respectively.
Clar's rule states that for a benzenoid polycyclic aromatic hydrocarbon (i.e. one with only hexagonal rings), the resonance structure with the largest number of disjoint aromatic π-sextets is the most important to characterize its chemical and physical properties. Such a resonance structure is called a Clar structure. In other words, a ...
Pyridine-N-oxides bind to metals through the oxygen. According to X-ray crystallography, the M-O-N angle is approximately 130° in many of these complexes. As reflected by the pKa of 0.79 for C 5 H 5 NOH +, pyridine N-oxides are weakly basic ligands. Their complexes are generally high spin, hence they are kinetically labile.