Synthesis and characterization of a series of monometallo-, bimetallo-, and heterobimetallo-1,2-ethene-linked cofacial bisporphyrins

The stepwise synthesis and characterization of a family of selectively metalated 1,2-bis[5-(2,3,7,8,12,13,17,18-octaethylporphyrinyl)]ethenes is described. These compounds are distinct from most of the previously reported bisporphyrin systems which possessed rigid linking groups or multiple strapping units, and their syntheses offer several advantages over the previously prepared systems. Among the members of this family we report the first heterobimetallic bisporphyrins able to exist as either cis (cofacial) or trans (extended) isomers including cis 13 {[Ni-II][Zn-II]}, cis 14 {[Ni-II][Cu-II]}, and trans 15 {[Cu-II][Mn-III]}. Products were characterized by H-1 NMR spectroscopy (except those containing Cu-II and/or Mn-III), visible spectroscopy, mass spectrometry, and elemental analyses. X-ray structural data are provided for bisporphyrins 4, 10, and 13-15: cis 4 (C74H88N8Co2), monoclinic, space group P2(1)/c, a = 21.097(15) Angstrom, b = 14.120(5) Angstrom, c = 22.987(11) Angstrom, beta = 108.59(4)degrees, Z = 4; cis 10 (C74H90N8Cu) monoclinic, space group P2(1)/c, a = 19.695(5) Angstrom, b = 14.427(3) Angstrom, c = 24.679(6) Angstrom, beta = 112.72(2)degrees, Z = 4; cis 13 (C74H88N8NiZn) monoclinic, space group P2(1)/c, a = 21.187(3) Angstrom, b = 13.9091(11) Angstrom, c = 22.682(3) Angstrom, beta = 108.674(10)degrees, Z = 4; cis 14 (C74H88N8NiCu) monoclinic, space group P2(1)/c, a = 21.169(3) Angstrom, b = 13.875(2) Angstrom, c = 22.660(3) Angstrom, beta = 108.64(9)degrees, Z = 4; trans 15 (C74H88N8CuMnCl), triclinic, space group P (1) over bar, a = 9.8123(13), b = 13.742(3), c = 14.774(3), alpha = 83.26(2), beta = 78.532(12), gamma = 78.347(14), Z = 1.