Crystal structures of H2[Me2dibenzo[14]tetraene]N4 and H2[Me2dixylyl[14]tetraene]N4: new tetraaza macrocycles
Abstract
Crystal structures are reported for H2[Me2dibenzo[14]tetraene]N4(I) and H2[Me2dixylyl[14]tetraene]N4(II), prepared by the condensation of o-phenylenediamine and dimethyl-o-phenylenediamine with 3-ethoxy-2-methylacrolein in dimethylformamide. The space groups are P21/n, with cell constants of a= 9.940(4)Å, b= 5.242(2)Å, c= 15.329(5)Å, B= 94.01 (3)°, Z= 2 for I, (C20H20N4), and a= 7.309(1)Å, b= 13.712(2)Å, c= 10.010(3)Å, B= 90.61(2)°, Z= 2 for II, (C2H28N4). The macrocycles possess a near-planar structure with the largest deviation of any non-hydrogen atom from the least-squares molecular plane being 0.117 Å for macrocycle I. The N-to-centre distance (RH) of 1.92 Å found in both I and II is smaller than that found in porphyrins and non-conjugated N4 14-membered macrocyclic rings such as cyclam, but very similar to the value found in phthalocyanines.