Alkyl and Aryl Substituted Corroles. 2. Synthesis and Characterization of Linked “Face-to-Face” Biscorroles. X-ray Structure of (BCA)Co₂(py)₃, Where BCA Represents a Biscorrole with an Anthracenyl Bridge

Abstract

The synthesis, spectroscopic properties, and electrochemistry of (BCA)Co(2) and (BCB)Co(2) are described where BCA and BCB represent biscorroles linked by an anthracenyl (A) or a biphenylenyl (B) bridge. The pyridine and CO binding properties of (BCA)Co(2) and (BCB)Co(2) are also presented, and one of the compounds in its pyridine-ligated form, (BCA)Co(2)(py)(3), is structurally characterized. The data on the biscorroles are compared on one hand to the monocorrole having the same substitution pattern and on the other hand to bisporphyrins having two Co(II) ions and the same anthracenyl or biphenylenyl linkers in order to better understand the interaction which occurs between the two corrole macrocycles. A parallel study on five different Co(III) phenyl-substituted corroles showed that bis-pyridine and mono-CO adducts are readily formed from the complexes in CH(2)Cl(2). This present paper examines how the ligand binding properties and electrochemistry of these Co(III) corroles are modified by the anthracenyl or biphenylenyl bridge which links the two macrocycles in a face to face orientation. An X-ray crystal structure was obtained for the tris-pyridine adduct of the anthracenyl bridged derivative, (BCA)Co(2)(py)(3), and gives the following results: C(127)H(99)Co(2)N(11).2CHCl(3), M = 2135.90, triclinic, space group P&onemacr;, a = 13.2555(5) A, b = 18.6406(8) A, c = 22.2140(9) A, alpha = 94.186(9) degrees, beta = 102.273(9) degrees, gamma = 94.205(9) degrees, V = 5326.8(4) A(3), 9293 independent reflections collected, R(F) = 0.066.

Design and Synthesis of Binucleating Macrocyclic Clefts Derived from Schiff‐Base Calixpyrroles

“…[16,56] In both of these cases, one cobalt centre is octahedral with one of the axial pyridine ligands bound within the binuclear cleft; even so, and unlike [Cu 2 A C H T U N G T R E N N U N G (m-py)(L …”

“…[11,14] Furthermore, it is possible to vary the two cofacial donor compartments to form porphyrin-corroles and bis-A C H T U N G T R E N N U N G (corrole) binuclear complexes; these compounds also catalyse oxygen reduction. [15,16] Other classes of polypyrrolic ligands, such as expanded porphyrins, have also been exploited in the formation of binuclear complexes, and, in contrast to cofacial diporphyrins, generally result in metal compounds that have flattened structures due to extensive p conjugation of the porphyrinic macrocycle. [17] In an effort to provide more co-ordinative flexibility and modularity of design, and also to surmount the sometimes arduous synthetic routes to cofacial and expanded porphy-A C H T U N G T R E N N U N G rins, focus has shifted to the development of Schiff-base porphyrin analogues as binucleating ligands for transition metals.…”

Synthesis and Physicochemical Characterization of Bis(macrocycles) Involving a Porphyrin and a meso‐Substituted Corrole – X‐ray Crystal Structure of a [(Free‐base porphyrin)–corrole]bis(pyridine)cobalt Complex

“…While this almost perpendicular orientation has also been observed in [(BCA)Co 2 (py) 3 ] (88.2°) [28] and [(Me 4 Ph 5 Cor)Co(py) 2 ] (83.7°), [27] in the [5,10,15-tris(pentafluorophenyl)corrole]cobalt(iii) complex a mutually parallel arrangement between both pyridine molecules is found for the monomer and dimer. [33] In the 5M(py) 2 crystal structure, the stacking of complexes is driven by two kinds of π-π interactions along the [1 0 0] direction (Figure 4).…”

“…Such a band is specific of the coordination of two pyridine molecules on the cobalt(iii) ion of the corrole moiety. [10,[27][28][29] Therefore, the coordination of two pyridine molecules is expected on the cobalt atom in endo and exo positions. The spectra in pyridine exhibit another band, at 456 nm, for both 4M and 4C complexes, corresponding to the Soret band of the corrole ring.…”

“…Thus, for the [5,10,15-tris-(pentafluorophenyl)corrole]cobalt(iii) complex, [33] M-N pyrrole and M-N py distances are 1.873-1.900 and 1.994 Å for the monomer, and 1.868-1.899 and 1.989-2.000 Å for the dimer. In the face-to-face homodimetallic bis(corrole) complex [(BCA)Co 2 (py) 3 ], [28] bearing three coordinated pyridine molecules (one inside and two out of the complex cavity), M-N pyrrole and M-N py distances are 1.879-1.905 and 1.976-1.979 Å for the hexacoordinate metal centre. In this latter structure, the coordination distances of the pentacoordinate metal centre, [1.875(4)-1.894 (4) for N pyrrole and 1.946(5) Å for N py ], compare well with those of the mono-metallic (corrole-porphyrin)cobalt(iii) complex, where the spacer is a biphenylenyl unit, [(PCB)H 2 Co(py)], [10] which binds one pyridine molecule out of the complex cavity.…”