Anthracene heme cyclophanes. Steric effects in carbon monoxide, molecular oxygen, and RNC binding

Traylor, Teddy G.; Tsuchiya, Soji; Campbell, D. H.; Mitchell, Michael; Stynes, Dennis V.; Koga, Noboru

doi:10.1021/ja00289a012

Cited by 103 publications

(90 citation statements)

References 5 publications

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“…The bulky 1,5-dicyclohexylimidazole, Cy21m, was chosen as axial base B because it is unable to coordinate under even the largest 717 cap (1 1). The affinities for the isocyanides are found to reflect-decreasing "Data at 20°C in toluene (for the present durene work), or in benzene or toluene for the other systems (1,8). bMeIm = N-methylimidazole; equilibrium constant for binding of CO to this complex = 6 X lo5 M -' at 20°C in toluene (1).…”

Section: Introductionmentioning

confidence: 70%

“…Cy21m was prepared according to a procedure described by Traylor et al (1). 'BuNC, TMIC, and "BuNC (Aldrich) were used as received.…”

Section: Methodsmentioning

confidence: 99%

“…The KTMIC values were thus determined using competitive ligation methods using both TMIC and CO, analogous to the procedure described by Traylor et al (1). From preliminary trial experiments, it became clear that binding of TMIC is comparable with, or stronger than, that of CO, and thus relative concentrations of TMIC and CO can be chosen to study the equilibrium K' for the overall displacement, reaction [ I 1,…”

Section: Durene-717 and -515 Systemsmentioning

confidence: 99%

“…Extensive studies (2)(3)(4)(5)(6)(7) involving the ligation of various isocyanides (RNC), including bulky ones, have proven useful for gaining an overall appreciation of the structural nature of the binding pocket within protein systems. More recently, isocyanide ligation studies have been extended to model hemes, where Traylor et al (1,8) have compared the affinities of sterically hindered five-coordinate anthracene (1) and adamantane (2) model hemes toward 'BuNC and tosylmethylisocyanide (TMIC, see Fig. l ) , two structurally dissimilar isocyanides which differ with respect to their relative steric requirements on coordination to the iron(I1) centre (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Binding of isocyanides to five-coordinate, durene-capped hemes

David¹,

James²,

Dolphin³

1987

Can. J. Chem.

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This paper is dedicated to Professor Do~iglas E. Ryan on the occasiorl of his 65th birthday SHANTHA DAVID, BRIAN R. JAMES, and DAVID DOLPHIN. Can. J. Chem. 65, 1098Chem. 65, (1987. Solution data at 20°C are presented for the binding of t-butylisocyanide and tosylmethylisocyanide (TMIC) to the five-coordinate hemes Fe(porp)(CyzIm), where CyrIm = 1,5-dicyclohexylimidazole and porp = the dianion of some durene-capped porphyrins with variable length linking methylene straps on either side of the durene moiety (4/4, 515, or 7/7 methylenes). The 'BuNC and TMIC ligands are used to probe the steric nature of the distal binding site under the cap, in particular the respective "central" and "peripheral" effects as defined by Traylor et al. The binding constants range from 1.1 X 10' M-' for the 7/7-TMIC system to immeasurably small for the 4/4-'BuNC system, this range spanning data reported in the literature for related anthracene-and adamantane-capped systems.SHANTHA DAVID, BRIAN R. JAMES et DAVID DOLPHIN. Can. J. Chem. 65, 1098 (1987). On rapporte des donnkes relatives 2 la complexation des isocyanures de tert-butyle et de tosylmCthyle (ICTM) avec des hkmes penta-coordonnCes Fe(porp)(CyrIm) dans lesquels CyzIm = dicyclohexyl-1,5 imidazole et porp = le dianion de porphyrines acappCes~ par un durene rattach6 par des unitis mCthylCniques de longueurs variables (4/4, 5/5 ou 717 mkthylenes). On a utilisC les ligands tert-BuNC et ICTS comme sondes pour la nature stCrique du site de complexation <

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Section: Introductionmentioning

confidence: 70%

“…Cy21m was prepared according to a procedure described by Traylor et al (1). 'BuNC, TMIC, and "BuNC (Aldrich) were used as received.…”

Section: Methodsmentioning

confidence: 99%

Section: Durene-717 and -515 Systemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Binding of isocyanides to five-coordinate, durene-capped hemes

David¹,

James²,

Dolphin³

1987

Can. J. Chem.

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“…5,8 Multiple effects from the protein have been identified, including steric hindrance, hydrogen bonding, and local polarity. 1,[13][14][15][16][17] However, due to the large size and the complex structure of protein, the interaction of protein with small molecules becomes extremely complicated. In addition, little attention has been paid to the small side ligands of porphyrin molecule itself.…”

Section: Introductionmentioning

confidence: 99%

Assistance of the Iron Porphyrin Ligands to the Binding Interaction between the Fe Center and Small Molecules in Solution

et al. 2014

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Solute-solvent electronic structure interactions of iron-porphyrin at very low concentration in dichloromethane (CH 2 Cl 2 ) liquid solution are reported. Two iron porphyrin complexes are investigated here, iron octaethylporphyrin chloride (FeOEP-Cl) and iron tetraphenylporphyrin chloride (FeTPP-Cl), using X-ray absorption and emission spectroscopy at the Fe L 2,3 edge, and spectra are interpreted with the help of density functional theory/restricted open shell configuration interaction singles (DFT/ROCIS) calculations. It is argued that the Fe center of FeOEP-Cl is more capable of binding small solvent molecules, exemplified here for Cl 2 CH 2 , than FeTPP-Cl in solution. The proposed binding mechanism is through the assistance of the dipole interaction between the porphyrin-ligand system and the solvent molecule, in a situation where the ligand structure and arrangement maximize the binding interactions. Our studies demonstrate that even small ligands, depending on their structure and arrangement, can have considerable effects on porphyrin's metal center chemistry in liquid solution.

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Molecular environment effect onO₂binding to lipidporphyrinatoiron(II) complexes in aqueous media

Tsuchida

Komatsu

Yanagimoto

2000

J. Porphyrins Phthalocyanines

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Lipidporphyrinatoiron(II) complexes are tetrakis(o-substituted)phenylporphinatoiron(II) derivatives which can be easily dispersed in water by molecular assembling. The most remarkable aspect of lipidporphyrinatoiron(II) assemblies is their reversible binding of dioxygen under physiological conditions (in aqueous media, pH 7.3, 37 °C) like hemoglobin and myoglobin. In these structures the O 2-binding properties are largely influenced by the molecular environment around the coordination site. Tetrakis(o-pivalamido)phenylporphinatoiron(II) with a covalently linked axial imidazole (lipidporphyrinatoiron(II), 1) is incorporated into recombinant human serum albumin (rHSA), providing a totally synthetic O 2-carrying hemoprotein (rHSA–1). Electrospray ionization mass spectrometry revealed the molecular mass of this non-covalent albumin–porphyrin hybrid. The O 2 rebinding after laser flash photolysis represented a three-phase decay, suggesting that each porphyrin is embedded into different cavities in the albumin structure. On the other hand, amphiphilic lipidporphyrinatoiron(II) with four alkylphosphocholine chains (2) is self-organized in aqueous solution to produce bimolecular fibers with a uniform thickness of 10 nm. This fiber also gave a stable O 2 adduct, and the O 2 rebinding after laser flash irradiation showed monophasic kinetics. Up to 20 vol% of methanol, which is a critical concentration for fiber formation, the morphology was gradually dissociated into spherical micelles, and the stability of the dioxygenated species suddenly decreased to 10% of that of the fibers.

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Anthracene heme cyclophanes. Steric effects in carbon monoxide, molecular oxygen, and RNC binding

Cited by 103 publications

References 5 publications

Binding of isocyanides to five-coordinate, durene-capped hemes

Binding of isocyanides to five-coordinate, durene-capped hemes

Assistance of the Iron Porphyrin Ligands to the Binding Interaction between the Fe Center and Small Molecules in Solution

Molecular environment effect onO₂binding to lipidporphyrinatoiron(II) complexes in aqueous media

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Anthracene heme cyclophanes. Steric effects in carbon monoxide, molecular oxygen, and RNC binding

Cited by 103 publications

References 5 publications

Binding of isocyanides to five-coordinate, durene-capped hemes

Binding of isocyanides to five-coordinate, durene-capped hemes

Assistance of the Iron Porphyrin Ligands to the Binding Interaction between the Fe Center and Small Molecules in Solution

Molecular environment effect onO2binding to lipidporphyrinatoiron(II) complexes in aqueous media

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Molecular environment effect onO₂binding to lipidporphyrinatoiron(II) complexes in aqueous media