Molecular Structure, UV/Vis Spectra, and Cyclic Voltammograms of Mn(II), Co(II), and Zn(II) 5,10,15,20-Tetraphenyl-21-oxaporphyrins

Abstract

The 5,10,15,20-tetraphenyl-21-oxaporphyrin complexes of Mn(II), Co(II), and Zn(II) have been crystallized and studied by X-ray diffraction, NMR and UV/vis spectroscopy, and mass spectrometry as well as cyclic voltammetry. The X-ray structure of the earlier described Cu(II) complex is also reported. All complex structures possess a five-coordinate, approximately square-pyramidal geometry with a slight deviation of the heteroaromatic moieties from planarity. The packing structures are characterized by parallel strands of complex molecules interacting by weak hydrogen bonds. In the case of Zn(II) an octahedral complex has also been isolated using a side-chain hydroxy functionalized oxaporphyrin ligand; the structure was verified by NMR and EXAFS spectroscopy. Cyclic voltammetry studies reveal that the reduction of the complex bound Mn(II), Co(II), and Zn(II) ions is a ligand-centered process whereas the first oxidation step depends on the metal ion present.

Light-Emitting Porphyrin Derivative Obtained from a Subproduct of the Cashew Nut Shell Liquid: A Promising Material for OLED Applications

“…According to Stute and coworkers [41], the E½ values depended on the number and nature of donor atoms in the porphyrin core. However, the influence of Cu(II) and Zn(II) on the reduction potentials was not as distinct as that of the ligand.…”

Copolymerization of Epoxides and CO2 by Cobalt(II) Oxaporphyrins with Mechanistic Explorations on Poly(Propylene Carbonate) Formation

“…On the other hand, tetraphenylporphyrin cobalt(III) cation (TPPCo(III) + ) had a molar mass of 671. In the recorded UV–vis spectra of OTPPCoCl and OTPPCoSbF 6 , a split of the Soret band at 420–450 nm was clear, which was induced by the asymmetrical nature of the oxaporphyrin ring (see Figures S6 and S9 in the Supporting Information) . In addition, the nitrogen content of the oxaporphyrins, measured by elemental analysis, strongly favored an N3O cavity (oxaporphyrin), rather than an N4 one (porphyrin).…”

“…A precursor for porphyrin preparation was first produced from furan and benzaldehyde using a literature method (step 1, Figure ) . A subsequent condensation of the thus‐afforded 2,5‐bis(phenylhydroxymethyl)‐furan with pyrrole and benzaldehyde yielded the desired oxaporphyrin ring (step 2, Figure ) . Due to the high basicity of this ligand, column separation was difficult.…”

“…Due to the high basicity of this ligand, column separation was difficult. Therefore, the crude macrocycle was utilized directly for metalation with cobalt(II) chloride, and the obtained metal complex, OTPPCoCl, could be easily purified by column chromatography (step 3, Figure ) . The other cobalt(II) catalyst, OTPPCoSbF 6 , was acquired through an anion exchange of OTPPCoCl with silver hexaluoroantimonate in dichloromethane …”

Crystal structure of chlorido(5,10,15,20-tetraphenylporphyrinato-κ4N)manganese(III) 2-aminopyridine disolvate

“…The majority of the known manganese-porphyrin species with halides are penta-coordinated, e.g. [Mn III (TPP)Cl] (Stute et al, 2013), [Mn III (TPP)Br] and [Mn III (TPP)I] (Turner et al, 1998). Nevertheless, the six-coordinated difluoro-manganese(IV) porphyrin species is also known: [Mn IV (TMP)F 2 ] (TMP is the 5,10,15,20-tetramesitylporphyrinato ligand) (Liu et al, 2012 (Cheng & Scheidt, 1996) and SENMUU (Paulat et al, 2006)], the equatorial manganese-N(pyrrole) distances (Mn-N p ) are in the range 2.002 (3)-2.019 (1) Å .…”