The crystal structure of biphenyltetracarboxylic dianhydride isomers

2,2',3,3'-Biphenyltetracarboxylic dianhydride (2,2',3,3'-BPDA)1 C16H6O6, M- r = 294. 21, monoclinic, P2(1)/c, a = 11. 694 (2), b= 8. 111 (2), c = 13. 4 94 (3) Angstrom, beta = 103. 47 (3)degrees, V = 1244. 7 (4) Angstrom(3), Z = 4, D-c = 1. 570 g/cm(3), F(000) = 450, MoK alpha radiation (lambda = 0. 7 1073 Angstrom), mu (MoK alpha) = 0. 092 mm(-1), R = 0. 0329 for 2180 observ ed reflections [I>2 sigma(I)]. 3,3',4,4'-Biphenyltetracarboxylic dianhydrid e (3,3',4,4'-BPDA)., C16H6O6, M-r = 294. 21, monoclinic, P2(1)/n, a = 6. 87 20 (14), b = 5. 1870 (10), c = 17. 288 (4) Angstrom, beta = 94. 96 (3)degre es, V = 613. 9 (2) Angstrom(3), Z = 2, D-c = 1. 592 gcm(-3), F(000) = 300, mu(MoK alpha) = 0. 125 mm(-1), R = 0. 0331 for 1079 observed reflections [I >2 sigma(I)]. The dianhydride isomers have different symmetry caused by alt ernating two anhydride group positions and the dihedral angle between the t wo phenyl rings are 62. 9 degrees for 2,2',3,3',-BPDA and 0 degrees for 3,3 ',4,4'-BPDA respectively.