75557-89-0Relevant academic research and scientific papers
Simple heme dimers with strongly cooperative ligand binding
Khvostichenko, Daria,Yang, Qing-Zheng,Boulatov, Roman
, p. 8368 - 8370 (2008/09/19)
(Graph Presented) Two is better than one: FeII complexes of new porphyrins exist as dinners that bind small ligands cooperatively, as illustrated by the sigmoidal binding curve (fractional occupancy of binding sites, a, versus free-ligand conce
H-bonded oxyhemoglobin models with substituted picket-fence porphyrins: The model compound equivalent of site-directed mutagenesis
Wuenschell, Gerald E.,Tetreau, Catherine,Lavalette, Daniel,Reed, Christopher A.
, p. 3346 - 3355 (2007/10/02)
Iron(II) complexes of picket-fence-type porphyrins having one of the four pivalamide pickets replaced by a substituent capable of H-bonding have been synthesized as models for oxyhemoglobin. This synthetic approach is analogous to site-directed mutagenesis of the distal residues in oxygen-binding hemoproteins. Rate and equilibrium data for dioxygen binding have been determined to evaluate the effect of the H-bonding substituent and to make comparisons with more passive substituents. The effect of H-bonding on the dioxygen affinity under standard conditions (25 °C, toluene solvent, 1,2-dimethylimidazole as axial ligand) is best illustrated by the ca. 10-fold increase observed when one pivalamide substituent of picket-fence porphyrin is replaced by a phenylurea substituent. Other substituents influence dioxygen adduct stability in a variety of ways to reveal that even with an apparently straightforward systematic approach, there can be considerable difficulty in partitioning the various factors that influence O2 affinity. This applies to both model compounds and mutant proteins.
Bis-Benzimidazole-Appended Binucleating Porphyrin Ligands: Synthesis, Characterization, and X-ray Structure
Larsen, Nigel G.,Boyd, Peter D. W.,Rodgers, Steven J.,Wuenschell, Gerald E.,Koch, Carol A.,et al.
, p. 6950 - 6960 (2007/10/02)
The synthesis and characterization of some new binucleating tetraarylporphyrin ligands is reported.The potentially most useful example is α,α,5,15-bis-α,α,10,20-bis(pivalamidophenyl)porphine (8).The ligands have two appended benzimidazole arms which are designed to chelate a second metal directly above the porphyrin.The synthetic methodology for obtaining both the 5,15 (i.e., trans) and the 5,10 (i.e., cis) bis-appended ligand from an α,α,α,α,5,10,15,20 tetra-functionalized starting material is described in detail.A key design feature of the ligand system is amenability to single-crystal X-ray structure determination and this is demonstrated with an X-ray structure of a copper(II) complex.Crystal data for CuC74H66N12O4*1.5(diethyl ether)*toluene are the following: monoclinic, C2/c, a = 31.240 (4) Angstroem, b = 16.769 (5) Angstroem, c = 35.199 (4) Angstroem, β = 121,4 (1) grad; R = 0.0823, Rw = 0.0826.H bonding between the benzimidazole moieties and the pivalamido pickets is seen to determine the structural disposition of the appendages lying above the porphyrin ring.Iron(III) porphyrin complexes of these new ligands exist in a hydroxo monomer form as well as the familiar μ-oxo dimer form.
Synthesis and Charactarization of "Tailed Picket Fence" Porphyrins
Collman, James P.,Brauman, John I.,Doxsee, Kenneth M.,Halbert, Thomas R.,Bunnenberg, Edward,et al.
, p. 4182 - 4192 (2007/10/02)
The synthesis of "picket fence" porphyrin derivatives bearing covalently attached axial bases is described.The porphyrins have been well characterized, primarily as the iron(II) complexes, meso-tri(α,α,α-o-pivalamidophenyl)-β-o-5-(N-imidazolyl)valeramidophenylporphinatoiron(II) and meso-tri(α,α,α-o-pivalamidophenyl)-β-o-4-(N-imidazolyl)butyramidophenylporphyrinatoiron(II), by UV/visible, MCD, 1H NMR, and Moessbauer spectroscopy, magnetic susceptibility, and elemental analysis.Preliminary results of carbon monoxide binding studies are reported.
