THE COORDINATION CHEMISTRY OF MACROCYCLIC 13-MEMBERED AND 14-MEMBERED DIPYRIDYLMETHANEAMIDES - CRYSTAL-STRUCTURE OF THE DEPROTONATED NI(II) COMPLEX OF 3,15-DIOXO-9-ETHYL-9-METHOXY-1,4,5,6,7,8,10,11,12,13,14,17,18,19,20,21,22,23-OCTADECADEHYDRO-2,16,22,23-TETRAAZATETRACYCLO[15.4.0.1(4,8).1(10,14)]TRICOSANE

Some 14-membered analogues of previously studied 13-membered macrocyclic dipyridylmethaneamides have been prepared. Tle ligands form complexes with several metal ions. Spectroscopic studies of Ni(II) and Cu(II) complexes of the deprotonated ligands with both 13- and 14-membered rings have demonstrated that the nickel complexes have square planar coordination while the copper complexes are either square pyramidal or octahedral. A remarkable selectivity was observed in the case of Pd(II) and Ni(II), which formed deprotonated complexes considerably faster with the 13-membered ring than with the higher homologue. The structure of the 13-membered macrocyclic title Ni(II) complex has been determined by X-ray diffraction. Crystal data: a = 8.446(1), b = 10.034(1), c - 11.209(1) angstrom, alpha = 84.09(1), beta = 74.33(1), gamma = 87.10(1)-degrees, triclinic, P1BAR, Z = 2. The complex is slightly bent. The four nitrogen atoms adopt a planar coordination geometry with the mean distances Ni-N(amide) = 1.820 and Ni-N(pyridine) = 1.848 angstrom. The molecules form a layer structure held together by electrostatic interactions besides the van der Waals' forces. The X-ray model was refined to R = 0.033 for 3936 reflections with I > 3sigma(I).