Iridium Complexes of 2,2′‐Bidipyrrins

Abstract

The reaction of [{Ir(cod)(μ‐Cl)}2] and K2CO3 or of [{Ir(cod)(μ‐OMe)}2] alone with the non‐natural tetrapyrrole 2,2′‐bidipyrrin (H2BDP) yields, depending on the stoichiometry, the mononuclear complex [Ir(cod)(HBDP)] or the homodinuclear complex [{Ir(cod)}2(BDP)]. Both complexes react readily with carbon monoxide to yield the species [Ir(CO)2(HBDP)] and [{Ir(CO)2}2(BDP)], respectively. The results from NMR spectroscopy and X‐ray diffraction reveal different conformations for the tetrapyrrolic ligand in both complexes. The reaction of [{Ir(coe)2(μ‐Cl)}2] with H2BDP proceeds differently and yields the macrocyclic [4e−,2H+]‐oxidized product [IrCl2(9‐Meic)] (9‐Meic = monoanion of 9‐methyl‐9,10‐isocorrole), which can be addressed as an iridium analog of cobalamin.

Advances in the Chemistry of Dipyrrins and Their Complexes

“…The preparation of a series of earlier transition metal ion complexes expanded the list of known coordination geometries available to bis(dipyrrin)s. 91,184,240,241 A rhodium(I) cluster complex (4, shown previously in Figure 7) is the only example of non-κ 2 bonding of a metal ion by a bis(dipyrrin). 91 This lead to an investigation which showed that the rhodium reagents used in the preparation of bis(dipyrrinato) rhodium complexes affected the structure of the product in terms of the metal-to-ligand ratio.…”

“…The preparation of a series of earlier transition metal ion complexes expanded the list of known coordination geometries available to bis(dipyrrin)s. ,,, A rhodium(I) cluster complex ( 4 , shown previously in Figure ) is the only example of non-κ 2 bonding of a metal ion by a bis(dipyrrin) .…”

Iron Chelates of 2,2′‐Bidipyrrin: Stable Analogues of the Labile Iron Bilins

“…[26][27][28] A substitution of hydrogen atoms for any other group at these positions would directly enhance the intramolecular repulsion and, therefore, the lability in complexes of such tetrapyrroles. 2,2'-Bidipyrrin compounds have been explored before as nitrogen-containing ligands in a number of mono-and dinuclear transition-metal chelates, [17,20,22,24,25,29,30] and the propensity of the terminal positions for chemical transformations has occasionally been documented. [31][32][33][34] Stable iron chelates, such as 2, can indeed be obtained from these ligands (Scheme 1), and we report herein the preparation, structure, spectroscopic analysis, and biomimetic reactivity of a unique series of iron 2,2'-bidipyrrin complexes [FeX-A C H T U N G T R E N N U N G (bdp)] (X = F, Cl, Br, I).…”

Making and Breaking Helical Open‐Chain Oligopyrroles

“…Not only do these reactions yield different metalation patterns on the ligand ( 34 , 35 , 36 ), but they also enable ring closure to closed‐chain tetrapyrroles (see earlier) [84] . The synthesis and behavior of iridium and ruthenium complexes is comparable [85–87] …”

“…[84] The synthesis and behavior of iridium and ruthenium complexes is comparable. [85][86][87] Lastly, iron chelates of dipyrrins can easily be synthesized from a suspension of FeCl 2 and FeCl 3 in 1,4-dioxane. [88] Here, the iron is coorrdinated as Fe(III) with an additional axial ligand such as Cl À .…”