Synthesis, Characterization, and Electrochemical Studies of β,β‘-Fused Metallocenoporphyrins

β,β‘-Fused monoruthenocenylporphyrins, Cp*Ru(III)[1,2-[M(II)-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)-porphyrinato]-3-methyl-cyclopentadienide] (M = Ni (20), Cu (21), Zn (22)), and bisferrocenoporphyrins, Fe(II) bis[1,2-[M(II)-5,10,15,20-tetraphenylporphyrinato]-3-methyl-cyclopentadienide] (M = Ni (24), Cu (25), Zn (26)), were synthesized
and characterized. A novel synthetic approach to β,β‘-fused porphyrins through Pd(0)-catalyzed [3 + 2] cycloaddition
was implemented in this work. UV−vis spectra of these compounds show largely broadened and red-shifted bands
(relative to their precursors) indicating potential electronic communication between the attached organometallic
moiety and the porphyrin core. The electrochemistry of these molecules suggests significant electronic interactions between the metallocene and metalloporphyrin in molecules 20 and 24. The crystal structure of the
bisferrocenoporphyrin 26, Fe(II) bis[1,2-[Zn(II)-5,10,15,20-tetraphenylporphyrinato]-3-methyl-cyclopentadienide], was
determined:  {Cp2Fe[ZnTPP(THF)]2}{Cp2Fe[ZnTPP(THF)ZnTPP(MeOH)]}·3MeOH·6THF, M = 3804.35, monoclinic,
space group P21/c, a = 33.327(5) Å, b = 19.145(3) Å, c = 29.603(5) Å, β = 106.309(2)°, V = 18128(5) Å3, Z
= 4. In this molecule, one porphyrin ring is rotated by about 72o with respect to the other in the 5-fold axis of the
Cp ring.