Lithium complexes porphyrins

Figure 49 One-pot construction of the two porphyrinic stoppers of copper(I)-complexed [2]-rotaxane (142). Also represented are the silver(l)- and lithium-complexed [2]-rotaxanes (144) and (145) [160].

Mechanisms of micellar reactions have been studied by a kinetic study of the state of the proton at the surface of dodecyl sulfate micelles [191]. Surface diffusion constants of Ni(II) on a sodium dodecyl sulfate micelle were studied by electron spin resonance (ESR). The lateral diffusion constant of Ni(II) was found to be three orders of magnitude less than that in ordinary aqueous solutions [192]. Migration and self-diffusion coefficients of divalent counterions in micellar solutions containing monovalent counterions were studied for solutions of Be2+ in lithium dodecyl sulfate and for solutions of Ca2+ in sodium dodecyl sulfate [193]. The structural disposition of the porphyrin complex and the conformation of the surfactant molecules inside the micellar cavity was studied by NMR on aqueous sodium dodecyl sulfate micelles [194]. 

Although direct reaction of lanthanide mono-porphyrins with free phthalo-cyanine or its lithium derivatives is generally more efficient than the template synthesis, and gives rise to mixed-ligand complexes, the template strategy can also be applied for synthesis of phthalocyanine-porphyrin complexes, as in the case of unsymmetric bisphthalocyanine complexes (Scheme 8.2, B(b)) [106, 136, 145, 146]. Thus, metallation of free porphyrins with lanthanide salts in TCB or n-octanol leads to single-decker complexes, which then react with phthalonitriles under the action of DBU in alcoholic media to give the desired compounds. 

The synthesis of metalloporphyrins which contain a metal-carbon a-bond can be accomplished by a number of different methods(l,2). One common synthetic method involves reaction of a Grignardreagent or alkyl(aryl) lithium with (P)MX or (PMX)2 where P is the dianion of a porphyrin macrocycle and X is a halide or pseudohalide. Another common synthetic technique involves reaction of a chemically or electrochemically generated low valent metalloporphyrin with an alkyl or aryl halide. This latter technique is similar to methods described in this paper for electrosynthesis of cobalt and rhodium a-bonded complexes. However, the prevailing mechanisms and the chemical reactions... 

H2TPP, followed by treatment with butyl lithium. The B—B distance is 1.71 A (Fig. 2). These early results indicate a rich chemistry for organoboron porphyrin complexes which should yield further examples without precedent in porphyrin... 

Interestingly, radical porphyrin derivatives with oxidation states intermediate between those of [16]-, [18]- and [20]porphyrin are known. In particular, neutral complexes of tetraarylporphyrins with lithium [102] and aluminum [103] were obtained and characterized in the solid state. These complexes of main-group metals are of interest, because the oxidation state of the metal ion is in each case well defined. 

PhC=CH and PhC=CPh analogs [Eq. (26)] (80). Five coordination is also found in the porphyrin alkyne complex, Mo(TTP)(PhC=CPh) (TTP= mesotetra-p-tolylporphyrin) (81). Reduction of a toluene solution of Mo(TTP)C12 with lithium aluminum hydride in the presence of excess diphenylacetylene produced the violet Mo(TPP)(PhC=CPh) adduct [Eq. (27)]. 

The lithium compounds, which, as noted earlier have square planar Li, are very soluble in polar solvents, are useful reagents for the synthesis of transition metal porphyrin complexes. There are also ionic species of the type [Li solv ]+[Li porph]". 

The porphyrin precursor octaethylporphrinogen (oepg) (10) has been used to form a yttrium complex [Li(thf)2][(oepg)Y(OEt)Li(thf)]. The ethoxide group, which is believed to arise from cleavage of thf, acts as a bridge between the yttrium and one lithium cation.146... 

The reaction of (OEP)ZrCl2 with 3equiv. of LiC=CPh produces the alkynyl (OEP)Zr(lv) porphyrin complex (OEP)Zr(7]1-C=CPh)3Li(THF) 242194 (Equation (18)). The molecular structure shows that three alkynyl ligands are coordinated to the Zr center in a piano-stool fashion and that the lithium cation is bound to the pocket formed by three alkynyl ligands. Treatment of complex 242 with anhydrous HC1 produces a C-C bond-coupled product H2C=C(Ph)=CPh and HC=CPh quantitatively. This example shows different reactivity of the zirconium porphyrin from that of analogous metallocene complexes. 

An interesting C-metalation of a coordinated pyrrol ligand in a rhenium complex has been described [19a]. Methylated aromatic hydrocarbons have been activated by (ZrCU) [19b], A novel mode of electrophilic activation of an aliphatic C-H bond, assisted by porphyrin complexes ofZr(IV) and achieved by the use of hydrides of lithium, sodium or potassium, has been reported [19c]. It has been shown that the ligands 2,3,5,6-tetraphenylphenoxide and 3,5-dimethyl-2,6-diphenylphenoxide undergo intramolecular activation by tantalum alkylidene groups at rates 20 and 100 times slower than that of the simple 2,6-diphenylphenoxide ligand [19d]. 

A novel mode of electrophilic activation of aliphatic C-H bonds also has been reported. This reaction is induced by Zr(IV) porphyrin complexes and achieved through the use of lithium, sodium or potassium hydrides [26]. 

A 5 mg (0.0068 mmol) porphyrin (8a) was dissolved in 0.5 mL 1,2-dichlorbenzene, then 4.5 mL DMF, 7 mg (0.015 mmol) ytterbinm acetylacetonate (3) and 5 mg lithium chloride were added. The mix was maintained for 15 min at 145°C and power 650 w in microwave oven. When reaction mass was cooled solvents were deleted at lowered pressure, and porphyrin complex was isolated by preparative chromatography on silica gel plates in chloroform. Weight 4 mg (58.4%). UV-vis 417.6 553.4 590.4 mn. Luminescent spectrum, 1. 980 nm (DMSO). 

Sigma-bonded alkyl, aryl, and perfluoroaryliron(III) porphyrins can be obtained by the reaction of (P)FeCl with either Grignard reagents or with alkyl or aryl lithium. The reaction of electrochemically generated iron(I) porphyrins and aryl or vinyl halides also leads to a-bonded Fe(III) porphyrin complexes as shown in Equation... 

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