175229-08-0Relevant articles and documents
2,3,5,6-Tetraalkoxy-1,4-benzoquinones and structurally related tetraalkoxy benzene derivatives: Synthesis, properties and solid state packing motifs
Keegstra, Erik M. D.,Huisman, Bart-Hendrik,Paardekooper, Elizabeth M.,Hoogesteger, Frans J.,Zwikker, Jan W.,Jenneskens, Leonardus W.,Kooijman, Huub,Schouten, Arie,Veldman, Nora,Spek, Anthony L.
, p. 229 - 240 (2007/10/03)
A general synthesis of 2,3,5,6-tetraalkoxy-1,4-benzoquinones 1 from 1,2,4,5-tetraalkoxybenzenes 3 is reported. IR analysis (1a-e), the single crystal X-ray analysis of 2,3,5,6-tetramethoxy-1,4-benzoquinone 1a and semi-empirical calculations (AM1, 1a) show that the 1,4-benzoquinone skeleton possesses a merocyanine-type distortion. The solid state packing motifs of 1 are markedly affected by alkoxy chain length. For 1a, weak C-H ... O interactions and reduction of unfavourable dipole-dipole interactions are important for intermolecular organization, whereas for 2,3,5,6-tetradecyloxy-1, 4-benzoquinone [1e, wide angle X-ray diffraction (WAXD)] the close packing principle of the alkyl chains dominates. In both cases the results show that interplanar overlap is improved with respect to 1,4-benzoquinone 8. To deepen our insight into the effect of alkoxy chain length on solid state packing motifs, single crystal X-ray structures of methoxy and decyloxy derivatives of the structurally related compounds 1,4-diacetoxy-2,3,5,6-tetraalkoxybenzenes 2a and e, and 1,2,4,5-tetraalkoxybenzenes 3a and e were analysed. Compounds 1e, 2e and 3e, bearing decyloxy chains, possess board-like molecular structures which stack parallel along the a-axis as a result of alkyl chain interactions.
