Rhodium corroles

The rhodium 3d binding energies are in the expected range for Rh3+ compounds. In general, rhodium corrolates present less positive rhodium atoms than rhodium porphyrinates. The observation is in agreement with the trianionic structure of the corrole moiety that increases electron density on the central metal atom facilitating the extraction of an electron. 

The electrochemical and spectroelectrochemical data for rhodium corrolate have been explained with the existence of monomers and dimers in solution and the reductions have been proposed to occur according to the mechanism shown in Fig. 23a. 

To date, only one example of a monovalent metallocorrole has been reported. It was reported in 1976 by Grigg, et al. and involves a rhodium corrole, which was obtained in 36% yield as the result of reacting free-base diethyl-hexamethyl corrole 2.6 with Rh2(CO)4Cl2. Unlike the trivalent corrole complex 2.134, obtained earlier by the treatment of a dideoxybiladiene-ac with this same metal salt, the complex isolated in this instance analyzed as being the monovalent Rh(CO)2Corrole, 2.157 (Scheme 2.1.42). This complex was later prepared in 72% yield,although it was... 

Simkhovich L, Mahammed A, Goldberg I, Gross Z (2001) Synthesis and characterization of germanium, tin, phosphorous, iron and rhodium complexes of tris(pentafluorophenyl)corrole, and the utilization of the iron and rhodium corroles as cyclopropanation catalysts. Chem Eur J 7 1041-1055... 

Metallation of dioxacorrole with Rh(CO)2Cl 2 gives a mono-Rh complex in which the monovalent rhodium atom is coordinated by two corrole nitrogens (Scheme S4).244... 

The stabilizing effect of an axial ligand has been previously observed in the synthesis of cobalt corrolates. Such an effect has been used to synthesize the complex where no peripheral p substituents are present on the macrocycle, which decomposes if attempts are made to isolate it in the absence of triphenyl-phosphine [10]. The behavior of rhodium closely resembled that of cobalt and it seems to be even more sensitive to the presence of axial ligands. [Rh(CO)2Cl]2 has also used as a metal carrier with such a starting material a hexacoordinated derivative has been isolated. The reaction follows a pathway similar to that observed for rhodium porphyrinates the first product is a Rh+ complex which is then oxidized to a Rh3+ derivative [29]. 

The distortion is the result of the strain imposed on the whole molecule by the geometric requirements of the corrole structure. It is not, however, very significant the rhodium atom is displaced by only 0.26 A from the plane of the four coordinating nitrogen atoms, a value much smaller than that observed in the structure of the P-unsubstituted complex Co(Corrole)PPh3 shown in Fig. 12 where the cobalt atom is displaced by 0.38 A from the macrocycle plane [32]. In both compounds the four coordinating nitrogen atoms are strictly coplanar. 

A most peculiar feature of the structure of Rh(OMC)AsPh3 is that the 15 atom core of the corrole moiety has an almost planar conformation. The deviation from the plane of best fit is 0.1 A and the maximum deviation of the rhodium atom from such mean plane is 0.19 A. 

It is interesting to note that in the structure of both rhodium and cobalt complexes the corrole framework shows a higher degree of planarity than that observed in the free ligand where a large distortion is induced by contacts between the inner hydrogen atoms [11]. The free base corrole macrocycle in its unprotonated form seems to be very flexible and the macrocycle core can expand to accommodate a large metal ion such as Rh3+ in a [Pg.89]

When Rh(III) corrole 2.132a (L = PPh3) is treated with excess t-butylisocya-nide, the corrole complex 2.133a is obtained, which contains a hexacoordinate rhodium center (Scheme 2.1.32). A similar product (2.133b) can be obtained from 2.132a by treatment with benzylisocyanide. 

In benzene, octamethylcorrole 2.162 reacts with Rh2(CO)4Cl2 in the presence of AsPh3 to afford both the rhodium(I) dicarbonyl complex 2.174 and the Rh(III) corrole derivative 2.132c (in 10% and 75% yield, respectively) (Scheme 2.1.52). ... 

Boschi T, Licoccia S, Paolesse R, Tagliatesta P, Tehran MA (1990) Synthesis and characterization of novel metal(III) complexes of corrole crystal and molecular structure of (2,3,7,8,12,13,17,18-octamethylcorrolato)(triphenylarsine)rhodium(III). J Chem Soc Dalton Trans 463 167... 

Simkhovich L, Galili N, Saltsman I, Goldberg I, Gross Z (2000) Coordination chemistry of the novel 5,10,15-tris(pentafluorophenyl)corrole synthesis, spectroscopy, and structural characterization of its cobalt(III), rhodium(III), and iron(IV) complexes. Inorg Chem 39 2704-2705... 

Simkhovich L, Iyer P, Goldberg I, Gross Z (2002) Structure and chemistry of -substituted corroles and their rhodium(I) and zinc(II) metal-ion complexes. Chem Eur J 8 2595-2601... 

Saltsman I, Simkhovich L, Balasz Y, Goldberg I, Gross Z (2004) Synthesis, spectroscopy, and structures of new rhodium(I) and rhodium(III) corroles and catalysis thereby. Inorg Chim Acta 357 3038-3046... 

Wagnert L, Berg A, Saltsman I, Gross Z, Rozenshtein V (2010) Time-resolved paramagnetic resonance study of rhodium(III) corrole excited states. J Phys Chem A 114 2059-2072... 

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