Transazobenzene

Transazobenzene is an organic compound with the chemical formula C12H10N2. It is a constitutional isomer of cisazobenzene, differing in the geometric arrangement around the central nitrogen-nitrogen double bond. In transazobenzene, the two phenyl groups are positioned on opposite sides of the azo double bond, resulting in a more stable and linear structure compared to its cis counterpart.

The synthesis of transazobenzene can be achieved through various methods, often involving the reduction of nitrobenzene derivatives or the oxidation of aniline. The trans isomer is generally the thermodynamically favored product under most conditions. It typically appears as a yellow crystalline solid.

Transazobenzene exhibits photoisomerization, meaning it can convert to its cis isomer upon irradiation with light of a specific wavelength, and vice versa. This photochromic behavior is a key characteristic of azobenzene derivatives and has led to investigations into their potential applications in areas such as molecular switches, optical data storage, and photoresponsive materials. The trans isomer is generally less soluble than the cis isomer. The electronic absorption spectrum of transazobenzene differs from that of cisazobenzene, with the trans isomer typically showing absorption at longer wavelengths.