Structure of the dye 2,6-dichloro-4′-N,N-diethylaminoazobenzene

The structure of 2,6-dichloro-4′-N,N-diethylaminoazobenzene has been determined from X-ray diffractometer data: C₁₆H₁₇Cl₂N₃, MW = 322·2, monoclinic, P2₁/n, a = 11·160 (2), b = 12·066 (2), c = 13·633 (3) Å, β = 116·46 (2)°, V = 1643·5 ų, Z = 4, D_c = 1·30 g cm^?3, F(000) = 672, λ(MoKα) = 0·71069 Å, μ(MoKα) = 3·94 cm^?1. The structure was solved by direct methods and refined to R = 0·073 for 1495 independent reflexions. The molecule is non-planar with a dihedral angle of 87·8° between the phenyl rings. The effects of substituents on the aromatic ring geometry are discussed. Significant molecular parameters are: NN, 1·164 (9) Å; mean ClC, 1·741 (6) Å; mean CN(azo), 1·487 (9) Å; NNC, 112·4 (2)° and 109·1 (2)°; NCC (cis relative to NN), 125·5 (3)° and 122·4 (2)°; NCC (trans relative to NN) 114·0 (3)° and 119·5 (3)°; mean CC(Cl)C, 122·3 (3)°.