STRUCTURE OF 4-CARBOXY-2-NITROBENZENEBORONIC ACID

4-(Dihydroxyboryl)-3-nitrobenzoic acid, C7H6BNO6, M(r) = 210.94, monoc linic, P2(1)/n, a = 10.542 (2), b = 6.411 (1), c = 13.105 (4) angstrom , beta = 106.47 (2)degrees, V = 849.3 (4) angstrom3, Z = 4, D(m) = 1.6 5 (flotation in CCl4/1,2-dibromoethane), D(x) = 1.649 Mg m-3, lambda(M o Kalpha) = 0.71073 angstrom, mu = 0.135 mm-1, F(000) = 432, T = 293 K , R = 0.0530 for 1328 observed reflections with F > 2sigma(F). The mol ecule is flat [the carboxy and nitro groups are rotated 5.8 (4) and 1. 9 (4)degrees, respectively, out of the plane] with the boronic acid gr oup almost normal to the plane of the benzene ring, 92.4 (3)degrees. T he B atom and one O atom of the nitro group are separated by only 2.45 7 (4) angstrom implying an interaction that is consistent with observe d chemical behavior.