Biarylstrukturer

Biarylstrukturer, also known as biphenyls or biaryls, are organic compounds consisting of two aryl (aromatic) rings linked by a single covalent bond. The most basic example is biphenyl itself, where two phenyl rings are directly connected. These structures are prevalent in organic chemistry and materials science due to their unique electronic and conformational properties. The dihedral angle between the two aryl rings, known as the twist angle, plays a significant role in their physical and chemical behavior. Steric hindrance from substituents on the rings can restrict rotation around the central bond, leading to atropisomerism, where different spatial arrangements (enantiomers) are stable and isolable. Biaryl structures are important building blocks in the synthesis of pharmaceuticals, liquid crystals, polymers, and organic electronic materials. Their rigid and extended pi-electron systems make them suitable for applications requiring specific optical or electronic properties. Suzuki, Heck, and Ullmann couplings are common synthetic methods employed for their formation. The electronic communication between the two aryl rings can be modulated by the nature and position of substituents, influencing their reactivity and photophysical characteristics.