The reaction of the starting materials [ Co II ( Porph )] (Porph = α,α,α,α-tetrakis(o-pivalamidophenyl)porphyrin (TpivPP) and the meso-tetraphenylporphyrin (TPP)) with an excess of 4,4′-bipyridine in chlorobenzene leads to the creation of two cobalt(II) derivatives: [ Co II (α,β,α,β- TpivPP )(4,4′- bpy )2]· C 6 H 5 Cl · C 6 H 14(1) and [ Co II ( TPP )(4,4′- bpy )2]·2 bpy (2). These compounds have been characterized by UV-vis, IR, 1 H NMR and MALDI-TOF spectroscopy. The proton NMR spectra of (1) and (2) clearly indicated that these derivatives are paramagnetic while the UV-vis data confirmed creation of a new six-coordinated or penta-coordinated Co ( II )-meso-porphyrin complexes by displaying red shifted Soret bands. The determined X-ray structures of (1) and (2) show that in the solid state these species are considered as coordination polymers which consist of 1D chains of alternating [ Co II ( Porph )] and 4,4′-bipyridine molecules located at the axial positions of the cobalt(II) coordination sphere. The coordination geometry of Co ( II ) in (1) and (2) is octahedral; the porphyrin (TpivPP or TPP) acts as a tetradentate chelating ligand with four nitrogen atoms from the pyrrole moieties occupying the equatorial positions along the porphyrin core. The N -donor atoms of the 4,4′-bipyridine create the axial ligands. It is noteworthy that for complex (1) the starting porphyrin is the α,α,α,α-TpivPP atropisomer but the final coordination polymer contains the α,β,α,β-TpivPP conformer.
The reaction of the cobalt(II) meso-tetraphenylporphyrin (TPP) starting material with an excess of 2-aminophenol (Hon) in organic solvents, yields the cobalt(II) porphyrin species [Co II (TPP)(Hon) 2 ] (1). This compound has been characterized by UV-vis, IR, MSI MS and 1 H NMR spectroscopy. The UV-vis data and especially the proton NMR results, for the isolated product, indicated that complex 1 is a Co(II) mesoporphyrin derivative. The X-ray molecular structure of the title compound bis(2-aminophenol) (tetraphenyl-porphyrinato) cobalt(II) has been determined. This structure is the first one reported of a metalloporphyrin with a 2-aminophenol axial ligand species. The central metal is hexacoordinated by the four nitrogen atoms of the pyrrole rings and the nitrogen atoms of the two Hon trans axial ligands.
In the title complex, [CoCl(C44H28N4)(C5H5N)]·0.5CHCl3 or [CoIII(TPP)Cl(py)]·0.5CHCl3 (where TPP is the dianion of tetraphenylporphyrin and py is pyridine), the average equatorial cobalt–pyrrole N atom bond length (Co—Np) is 1.958 (7) Å and the axial Co—Cl and Co—Npy distances are 2.2339 (6) and 1.9898 (17) Å, respectively. The tetraphenylporphyrinate dianion exhibits an important nonplanar conformation with major ruffling and saddling distortions. In the crystal, molecules are linked via weak C—H⋯π interactions. In the difference Fourier map, a region of highly disordered electron density was estimated using the SQUEEZE routine [PLATON; Spek (2009 ▶), Acta Cryst. D65, 148–155] to be equivalent to one half-molecule of CHCl3 per molecule of the complex.
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