Perpendicularly Arranged Ruthenium Porphyrin Dimers and Trimers

Abstract

A series of ruthenium(II) porphyrin dimers and trimers (carbonyl dimers, 1-4; carbonyl trimers, 5-7, bis(pyridyl) trimers, 8-10), having axial or bridging porphyrin ligands, were synthesized and characterized by (1)H NMR and IR spectroscopy and mass spectrometry. An X-ray structural determination of Ru(II)(OEP)(CO)(H(2)PyP(3)P) (1) (OEP = octaethylporphyrinato dianion, H(2)PyP(3)P = 5-pyridyl-10,15,20-triphenylporphyrinato dianion) was carried out. The axial porphyrin ligand is coordinated to the ruthenium porphyrin subunit obliquely. The Ru-N(Py) bond length is 2.237(4) Å, and the angle between the ruthenium porphyrin macrocycle and the pyridyl ring is 63.23(35) degrees. Crystallographic data for 1 are as follows: chemical formula C(80)H(73)N(9)ORu.CH(2)Cl(2), triclinic, P&onemacr;, a = 14.954(5) Å, b = 25.792(5) Å, c = 10.124(3) Å, alpha = 90.21(2) degrees, beta = 108.43(2) degrees, gamma = 73.39(2) degrees, Z = 2, R(F) = 0.0674. (1)H NMR signals of 2,6- and 3,5-pyridyl protons of the axial ligand porphyrins of the oligomers 1-10 showed significant upfield shifts, indicating that the axial porphyrin subunits are coordinated to the ruthenium porphyrin subunits through the pyridyl group in solution. UV-vis spectra revealed the presence of excitonic interaction between two axial ligand porphyrin subunits in the trimers 8-10. The MLCT bands from the central ruthenium(II) ions to the octaethylporphyrin rings were observed around 450 nm in 8 and 9. Cyclic voltammograms of the carbonyl dimers and trimers showed no redox waves of the ruthenium(II) ions, because the ruthenium(II) oxidation state of these complexes was significantly stabilized by the coordination of the axial CO ligands. On the other hand, bis(pyridyl) trimers exhibit the Ru(III/II) waves in the region of -0.12 to +0.15 V vs Ag/Ag(+) reference electrode.

Synthesis and molecular structures of N,N-dialkyl-4-nitrosoaniline adducts of formally d6 metalloporphyrins of ruthenium and cobalt

“…Selected bond lengths and angles are shown in Table 2. The Ru-N(por) distances are 2.049(2) and 2.053(2) Å , and fall in the range observed for other Ru II (OEP)-containing complexes (2.036(6)-2.090(4) Å ) [12][13][14][15][16][17][18][19][20][21][22][23]. The Ru-N(axial) and N-O distances are 2.013(6) and 1.248 (7) We were also interested in determining whether such Nbinding would exist in cationic d 6 metalloporphyrins, or whether the nitrosoarene binding would be dominated by Obinding as a result of the contribution of the dipolar resonance form (Fig.…”

Sawhorse-type diruthenium tetracarbonyl complexes containing porphyrin-derived ligands as highly selective photosensitizers for female reproductive cancer cells

“…The second reduction is probably one-electron reduction as well but occurs at the onset of the base electrolyte decomposition. It is worth noting that the B-D-E waves (Table 2) are observed in a similar pattern and at roughly similar potentials as for free 5-(4-pyridyl)-10,15,20-triphenyl-21,23H-porphyrin [30]. This indicates that coordination via the peripheral pyridine moiety has only a minor influence (e.g., inductive) on the redox properties of the porphyrin framework.…”

Enhanced activity of enantioselective (salen)Mn(III) epoxidation catalysts through supramolecular complexation

“…Unfortunately, our efforts to obtain a crystal structure of supramolecular complex 1 have not been successful to date, but a similar structure consisting of meso-tetra(4-pyridyl)porphyrin and two equivalents of ZnTPP has recently been characterized through X-ray crystallographic studies [22]. Coordination polymers of zinc [21] and other pyridine-functionalized transition-metal porphyrins, such as osmium [23] and ruthenium [24] have also been characterized in both solution and solid states.…”