Crystal Structures of Lanthanum Complexes with Nitrobenzoic Acids

摘要

The crystal structures of LaL_3.2H_2O(HL=o-nitrobenzoic acid) (I), LaL'_3·2.5H_2O(HL'=p-nitrobenzoic acid) (II) and LaL"_3·2H_2O (HL"=m-nitrobenzoic acid) (III) were determined. I crystallized in the monoclinic system, space group P2_(1), and both II and III crystallized in the triclinic system, space group P1. Mr=673.27[682.28, 673.27], a=9.073(2)[9.488(2), 13.925(2)],b=21.457(6)[19.035(6), 15.102(4)], c=12.798(4)[l5.275(4), 13.446(3)]A, α =90[105.21(2), 101.52(2)], β=95.94(2)[101.60(2), 116.88(1)], γ=90[81.24(2), 88.04(2)]°, V=2478(l)[2593(1), 2466(1)]A~3, Z=4[4, 4], Dc=1.80[1.75, 1.81]g/cm~3, F(000)=1328[1348, 1328], μ=18.4[17.6, 18.5]cm~(-1), R=0.038[0.043, 0.058]. The coordination numbers of lanthanum ions in three compounds are nine. The carboxyl groups coordinate lanthanum ions in three modes: chelating, bridging and terdentate, and none of the nitro groups is coordinated. There are no discrete molecules of complexes in each of them, and each complex shows a polymeric chain structure.