Metal Complexes with Tetrapyrrole Ligands, XLV. The Mercuration of Nickel(II), Palladium(II), and Platinum(II) Porphyrins

Abstract

<jats:title>Abstract</jats:title><jats:p>The mercuration of 5,10,15,20-tetrakis(4-methylphenyl)porphyrin complexes M(TTP)** (2a-c; M = Ni, Pd, Pt) is described. Treatment of Ni(TTP) (2a) with mercuric acetate in refluxing benzene and subsequently with aqueous sodium chloride yields a mixture of species M(TTP-Hg<jats:sub>n</jats:sub>I<jats:sub>n</jats:sub>) (1 &lt; n &lt; 3) from which the monomercurial, Ni(TTP-HgCl) (3a) is isolated in 35% yield after silica chromatography. A more rapid reaction occurs with mercuric trifluoroacetate in chlorobenzene. With this system, Pd(TTP-HgCl) (3b) and Pt(TTP-HgCl) (3c) along with their bis-, tris-, and tetrakis-mercurated analogs are obtained. The reaction times indicate that replacement of Ni<jats:sup>II</jats:sup> by Pd<jats:sup>II</jats:sup> and Pt<jats:sup>II</jats:sup> progressively diminishes the rate of electrophilic attack at the porphyrin periphery, consistent with a decrease of the total density of negative charge on the porphyrin ligand in these complexes.</jats:p>

Benziporphyrins: Exploring Arene Chemistry in a Macrocyclic Environment

“…This is particularly evident with the 32-Hg(CF 3 CO 2 ) complex, obtained from mercury(II) trifluoroacetate, which is known to efficiently mercurate porphyrins. 39 However, during the insertion of nickel(II) to m-benziporphyrin, the initially forming 32-NiCl was subsequently transformed into the organometallic 27-Ni species. It was therefore expedient to bring the reaction to completion and then convert the isolated 27-Ni into 32-NiCl by addition of gaseous HCl (Scheme 20).…”

Synthesis and Functionalization of Porphyrins through Organometallic Methodologies

“…In the beginning of work on directly metalated porphyrins, the mercuration of porphyrins was extensively examined. − The reaction of porphyrin 13.1 with mercury­(II) diacetate afforded trimercurated porphyrin 13.2 , functionalized at two β-positions and one meso -position (Scheme ). Sugiura, Arnold, and co-workers succeeded in the regioselective mercuration of porphyrins (Scheme ).…”

“…Smith and co-workers reported palladiumcatalyzed C−C bond formation with a Zn(II) 2,4-bismercurated porphyrin (Scheme 90). 125 Bismercurated deuteroporphyrin 90.1 was prepared by mixing an excess of mercury(II) acetate with the zinc(II) deuteroporphyrin dimethyl ester. Compound 90.1 was reacted with acrolein in an acetonitrile/ DMF mixture in the presence of a trace amount of triethylamine and a stoichiometric amount of LiPdCl 3 to afford the vinylated product 90.2 in 35% yield.…”

Peripherally η1-Platinated Organometallic Porphyrins as Building Blocks for Multiporphyrin Arrays

“…The recent discovery and investigation of modified porphyrin macrocycles such as inverted or “N-confused” porphyrins and azuliporphyrins have somewhat increased the number of examples in this area; however, the centrally coordinated metal still participates in the organometallic character of the molecule. There are also limited examples of porphyrins with an externally bound organometallic fragment, which include examples of both σ- and π-bonded organometallic moieties …”