STRUCTURE OF P-N,N-DIMETHYLAMINOBENZOIC ANHYDRIDE

p-N,N-Dimethylaminobenzoic acid anhydride (C18H20N2O3, Mr=312.37), mon oclinic, Ic, a=10.601(1), b=12.600(2), c=12.416(2) Angstrom and beta=9 4.077(4)degrees, V=1654.32 Angstrom(3), Z=4, D-x,=1.254 g cm(-3), F(00 0)=664, lambda(MoK alpha=0.71073 Angstrom, mu(MoK alpha)=0.50 cm(-1), T=295 K. R and wR = 0.0367 and 0.0397, respectively for 1262 unique re flections [\F\ > 3.92 sigma(F)]. The molecule exhibits high contributi on of the quinoid structure to the ring geometry. The structure is pol ar but not chiral. The comparison of several para and meta substituted benzoic anhydrides was performed.