Tetramethyl-porphyrin complexes

A/ -tetramethyl-p-phenylenediamine). The solution structure of the TNB was uniquely determined (661) and found to be that of a peripheral complex (arising from pure n-n interaction) with an interplane spacing of 320 + 20 pm and with TNB centred approximately over a pyrrole. Analogous Ni(ii) porphyrin complexes have been examined. (659, 662)... 

The coordination chemistry of second-row transition metal corroles is less extensive than for first-row metals, but there are now numerous examples. The synthesis of brick red (oxo)Mo(mec) (mec = 2,3,17,18-tetramethyl-7,8,12,13-tetraethylcorrolate) was reported in a 1977 letter [63]. The first Ru corrole was synthesized as a cofacial Ru(III)-Ru(III) dimer in 2000 [64] the synthesis of a monomeric Ru corrole was achieved in 2003 [65]. A dicarbonylrhodium(I) A -me thy I corrole complex, where Rh(I) is bound to two of the ring nitrogen atoms, was reported in 1976 [66], while the synthesis of a Rh(III) corrole was published a dozen years later [67]. A series of Ag(III) corroles was described in 2003 [68]. This oxidation state assignment was supported by an X-ray photoelectron spectroscopy (XPS) comparison to cationic Ag(III) porphyrin complexes. 

On first discovery of CCTP, the Co(II) complexes were based on porphyrin complexes, for example, Co(II) hematopor-phyrin IX tetramethyl ether (17). 

A logical extension of the condensation reactions which yield multidentate nitrogen donors is the formation of macrocyclic ligands. The preference of palladium for square planar coordination makes it an ideal metal for the formation of complexes of these ligands. Thus palladium porphyrins are very stable and resistant to demetallation.281 Both 14- and 16-atom macrocycles have been used to form complexes. The ligand l,8-dihydro-5,7,12,14-tetramethyl-dibenzo[b,i][l,4,8,ll]tetraaza[14]annulene reacts with [PdCl2(PhCN)2] to yield the complex (46). 

This work, which has flourished as the result of contributions from numerous research groups, served to establish that pyxole-containing entities far less complex than expanded porphyrins can act as effective anion receptors. In fact, Gale and coworkers recently demonstrated that pyrrole can stabilize an anion complex, at lease in the solid state. Specifically, these latter workers succeeded in elucidating the crystal structure of a pyrrole-chloride complex prepared by crystallizing tetramethyl-ammonium chloride from pyrrole (Fig. In this... 

In addition octaethylporphyrin (OEPHj), tetramethyl- and tetraphenylpor-phyrin (TMPHj and TPPH2), dihydrodibenzotetraaza[14]-annulene (taaH2) and hemiporphyrazine (HPH2) are other examples of macrocycles which have been investigated in efforts to construct new types of conducting materials. In the following we will concentrate on phthalocyaninatometal complexes, tetrabenzoporphyrins, 1,2- and 2,3-naphthalocyanines and tetra(2,3-naphtho)-porphyrins. 

Other types of planar NO microsensors include Pt microelectrodes chemically modified by electrodeposition of metaUoporphyrin-like nickel(II) complexes. For example, tetrasul-fonated phthalocyanine tetrasodium (NiTSPc) was electrodeposited on the bare electrode surface by repetitive cychc voltammetry (21). Alternatively, electrode functionalization using nickel(4-iV-tetramethyl)pyridyl porphyrin (NiTmPyP) as an electrocatalyst was also carried out by applying multiple pulses in differential pulse amperometry (22). In this case, the electrocatalyst was entrapped in a NO selective polymer network of a negatively charged acrylic acid resin that prevented access by anionic interfering species. 

Miscellaneous Metal Ions.—Mention has been made already of a relatively slow formation reaction for the normally labile manganese(ii) ion. Incorporations of the labile bivalent metal ions zinc(ii), copper(ii), manganese(n), cobalt(ii), and nickel(n) into water-soluble porphyrin molecules such as tetrakis-(4-N-methyI-pyridyl)porphine, tetrasulphonated tetraphenylporphine, and uroporphine are also relatively slow reactions. However, by taking into account the porphyrin deformation which is necessary, an Id mechanism can be fitted to these reactions. The rates of formation and dissociation of nickel(ii), copper(n), cobalt(ii), and zinc(ii) complexes of the sterically hindered ligand 1,4,8,11-tetramethyl-1,4,8,11-tetra-azacyclotetra-decane (Meicyclam) are also 10 —10 smaller than is normal for these metal ions. ... 

The iron complex 2,7,12,17-tetramethyl-3,13-octadecyl-8,18-bi(carbometaxyethyl)porphyrin (FeP). 

Porphyrins. 5>Acetoxymethyl-4- (2 -methoxycarbonylethyl) -3-methylpyrrole-2-carboxylic acid refluxed 7 hrs. in methanol-glacial acetic acid containing cobaltous chloride, then aerated 12 hrs., dil. with water, made alkaline with NH3, and extracted with chloroform coproporphyrin III tetramethyl ester cobalt complex. Y 52%. F. e. and procedures, with lower yields, s. A. W. Johnson et al., Soc. 1959, 3416. 

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