In memoriam Ai ItasakaHexanuclear rhenum(iii) cluster complexes are the subject of extensive current studies [1±17] because of their redox and photoluminescent properties as well as the versatility of the design of the coordination environment around the hexarhenium cores, Re 6 (m 3 -E) 8 (E S, Se). The cores may be regarded as a giant octahedral center, since the six terminal ligands are oriented in such a manner that each pair of neighboring ligands are arranged vertically to each other. It is possible to mimic the chemistry of simple octahedral metal complexes by using the hexarhenium cluster core, as ligand substitution at the six terminal sites of the core can be controlled with respect to the number and geometrical arrangements of the terminal ligands. Examples are the preparation of a series of pyridine (py) complexes, [Re 6 (m 3 -S) 8 Cl n (py) 6Àn ] (2Àn) (n 2 ± 4), which included the isolation of two isomers (cis and trans) for n 2, [4,13] and the bridge-chelate formation around the core by a long-chain bidentate ligand, (C 6 H 5 ) 2 P(CH 2 ) 6 P(C 6 H 5 ) 2 . [14] Another important aspect of using a giant octahedral center is to arrange as many as six sterically bulky ligands around the core, something that is difficult around a single metal center.In the past few years, we have been studying the preparation and properties of some oligomeric porphyrins that are constructed through coordination of pyridylporphyrins to metalloporphyrins. [18±26] Although the octahedral arrangement of the porphyrin ligands is interesting as an important structural motif and also as a building block of certain supramolecular complexes, it is too bulky to make stable six-coordinate mononuclear metal complexes. We now show that the octahedral arrangement of porphyrins is possible by using the hexarhenium cores. The new com-plexes 1 ± 4 (H 2 PyT 3 P 5-(4-pyridyl)-10,15,20-tritolylporphyrin) are reported herein.[Re 6 (m 3 -S) 8 (H 2 PyT 3 P) 6 ] 2 1[Re 6 (m 3 -S) 8 (ZnPyT 3 P) 6 ] 2 2[Re 6 (m 3 -Se) 8 (H 2 PyT 3 P) 6 ] 2 3[Re 6 (m 3 -Se) 8 (ZnPyT 3 P) 6 ] 2 4The complexes 1 and 3 containing free-base porphyrins were prepared by the substitution of 5-(4-pyridyl)-10,15,20tritolylporphyrin for the solvent molecules in [Re 6 (m 3 -S) 8 -(CH 3 CN) 6 ] 2 and [Re 6 (m 3 -Se) 8 (CH 3 CN) 6 ] 2 , respectively, in chlorobenzene. Zinc(ii) ions were introduced into the porphyrins in 1 and 3 by reacting them with zinc acetate in CH 2 Cl 2 to give 2 and 4, respectively.The structure of 3-(SbF 6 ) 2 was determined by single-crystal X-ray structure analysis. [27] Figure 1 shows the remarkable structure of 3. Six H 2 PyT 3 P groups coordinate to the [Re 6 Se 8 ] 2 core through the pyridyl group. The bond lengths and angles in the [Re 6 Se 8 ] 2 core reveal that the rhenium selenide cluster core has virtually O h symmetry as in other hexarhenium chalcogenide complexes. [3, 7±14, 28±34] The complex ion has a cystallographically imposed inversion center. In addition, six H 2 PyT 3 P groups are arranged essentially in a C 3 manner around the [R...

Rhodium(III) porphyrin complexes, [Rh(4-PyT(3)P)Cl](4) (1) and [Rh(2-PytB(3)P)Cl](2) (2) (4-PyT(3)P = 5-(4-pyridyl)-10,15,20-tritolylporphyrinato dianion, 2-PytB(3)P = 5-(2-pyridyl)-10,15,20-tri(4-tert-butyl)phenylporphyrinato dianion), were self-assembled and characterized by (1)H nuclear magnetic resonance spectroscopy, infrared spectroscopy, and electron spray ionization-mass spectroscopy methods. The spectroscopic results certified that the rhodium porphyrin complexes 1 and 2 have a cyclic tetrameric structure and a cofacial dimeric structure, respectively. The X-ray structure analysis of 1 confirmed the cyclic structure of the complex. The Soret bands of both oligomers were significantly broadened by excitonic interactions between the porphyrin units, compared to those observed for a corresponding analogue of Rh(TTP)(Py)Cl (TTP = 5,10,15,20-tetratolylporphyrinato dianion, Py = pyridine). Stepwise oxidation of the porphyrin rings in the oligomers was observed by cyclic voltammetry. The oligomers 1 and 2 are very stable in solution, and they slowly undergo reactions with pyridine to give corresponding monomer complexes only at high temperatures (approximately 80 degrees C).

A porphyrin ball: An octahedral arrangement of six porphyrins is achieved by the coordination of 5‐(4‐pyridyl)‐10,15,20‐tritolylporphyrins (H2PyT3P) to the octa(μ3‐S/μ3‐Se)hexarhenium(III) core. Six porphyrin ligands are arranged virtually in an S6 manner as the X‐ray structural analysis of [Re6(μ3‐S)8(H2PyT3P)6](SbF6)2 shows (see picture).

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