The pi-pi charge-transfer interactions of bipyridinium with dioxyarenes or diaminoarenes have been used extensively for the construction of mechanically interlocked systems and in crystal engineering.
The use of crown ether binding with metal or ammonium cations is ubiquitous in supramolecular chemistry.
The formation of carboxylic acid dimers and other simple hydrogen bonding interactions.
The complexation of bipyridines or tripyridines with ruthenium, silver or other metal ions is of great utility in the construction of complex architectures of many individual molecules.
The complexation of porphyrins or phthalocyanines around metal ions gives access to catalytic, photochemical and electrochemical properties as well as complexation. These units are used a great deal by nature.
Bipyridines
form a family of chemical compounds with the formula. They are derived by the coupling of two pyridine rings. Six isomers of bipyridine exist. Two isomers are prominent: bipyridine is a popular ligand in coordination chemistry and 4,4'-bipyridine is a precursor to the herbicide paraquat. The bipyridines are colourless solids, which are soluble in organic solvents and slightly soluble in water.
Inamrinone and Milrinone are used occasionally for short term. They inhibit phosphodiesterase by increasing cAMP, exerting positive inotropy and causing vasodilation. Amrinone causes thrombocytopenia; Milrinone decreases survival in heart failure.
Silver
has been known since ancient times and has long been valued as a precious metal, used to make ornaments, jewellery, high-value tableware and utensils (hence the term "silverware") and currency coins. Today, silver metal is used in electrical contacts and conductors, in mirrors and in catalysis of chemical reactions. Its compounds are used in photographic film and dilute solutions of silver nitrate and other silver compounds are used as disinfectants. Although the antimicrobial uses of silver have largely been supplanted by the use of antibiotics, its antiseptic properties are still a useful tool in the prevention and treatment of sepsis and infections caused by antibiotic-resistant microorganisms such as MRSA.