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Nguyen THT, Eerdun C, Okayama T, Hisanaga S, Tominaga T, Mochida T, Setsune JI. Stereochemistry and chiroptical properties of bimetallic single helicates of hexapyrrole-α, ω-dicarbaldimines with high diastereoselectivity. J PORPHYR PHTHALOCYA 2021. [DOI: 10.1142/s108842462150111x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bimetallic complexes of hexapyrrole-[Formula: see text],[Formula: see text]-dicarbaldimines consisting of a pair of four-coordinate metal sites adopt a helical closed [Formula: see text]-symmetric form or sigmoidal open forms depending on whether the 2,2[Formula: see text]-bipyrrole subunit at the center of the hexapyrrole chain takes cis- or trans-conformation. X-ray crystallography of a bisNi complex having N-[([Formula: see text]-1-cyclohexylethyl]carbaldimine units at both ends of the hexapyrrole chain revealed a non-symmetric heterohelical open form where the metal coordination sites of opposite helical sense sit on opposite sides of the central 2,2[Formula: see text]-bipyrrole subunit. BisPd complexes preferred a closed [Formula: see text] form and a steric bulk at the 3,3[Formula: see text]-position of the 2,2[Formula: see text]-bipyrrole subunit improved the helical sense bias. A bisPd complex with N-[([Formula: see text]-1-cyclohexylethyl]carbaldimine units adopts a helical closed [Formula: see text] form exclusively with full bias for a [Formula: see text]-helical sense. These bimetallic single stranded helicates were reversibly oxidized to [Formula: see text]-cation radicals at 0.1[Formula: see text]0.3 V vs. a ferrocene/ferrocenium couple and spectroelectrochemistry revealed remarkable absorption and CD spectral changes in the Vis-NIR region.
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Affiliation(s)
- Thi Hien Thuy Nguyen
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Chaolu Eerdun
- School of Pharmaceutical Science, Inner Mongolia Medical University Jinshan Econimic & Technology Development District, Hohhot 010100, China
| | - Takuya Okayama
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Satoshi Hisanaga
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Takumi Tominaga
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Tomoyuki Mochida
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Jun-ichiro Setsune
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
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Sarabi S, Jamaat PR, Djahaniani H. Theoretical kinetics and thermodynamics study: Peripheral substituent effects on the hydrolysis of verdoheme. J PORPHYR PHTHALOCYA 2020. [DOI: 10.1142/s1088424620500418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The heme oxygenase (HO) enzyme is a free heme protein that binds to heme in the body. Heme acts as both a cofactor and a substrate in this enzyme. The catabolism of heme into biliverdin, monoxide carbon, and free-iron, catalyzed by heme oxygenase via three consecutive oxygenation steps, in which the heme group functions as the prosthetic group as well as the substrate. Investigations of the reactions of the peripheral substituent on the heme ring with 5-oxaporphyrin iron complexes (verdohemes) have been assumed to provide models and largely unknown for the primary step in the hydrolysis of verdohemes. In this work, a theoretical kinetics and thermodynamics study of the degradation reactions of verdohemes was performed, and calculations show that the [Formula: see text] in the hydrolysis of verdohemes with non-peripheral substituents is more negative than hydrolysis of verdohemes with peripheral substituents. In other words, the hydrolysis of verdohemes with non-peripheral substituents is more energy-efficient than verdohemes with a peripheral substituents. Equilibrium constant calculations show that hydrolysis of verdohemes with non-peripheral substituents is much faster than that of verdohemes with peripheral substituents, which is due to a more convenient nucleophilic attack on the cationic ring than the anionic ring. To acquire a good molecular understanding, peripheral substituent effects on the hydrolysis of verdoheme’s inhibitory role was studied using the DFT method.
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Affiliation(s)
- Shahriyar Sarabi
- Department of Chemistry, East Tehran Branch, Islamic Azad University, Tehran, Iran
| | | | - Hoorieh Djahaniani
- Department of Chemistry, East Tehran Branch, Islamic Azad University, Tehran, Iran
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Eerdun C, Nguyen THT, Okayama T, Hisanaga S, Setsune JI. Conformational Changes and Redox Properties of Bimetallic Single Helicates of Hexapyrrole-α,ω-dicarbaldehydes. Chemistry 2019; 25:5777-5786. [PMID: 30746784 DOI: 10.1002/chem.201900353] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Indexed: 11/07/2022]
Abstract
The hexapyrrole-α,ω-dicarbaldehydes 1 a and 1 b were metallated with CuII , NiII , and PdII to give bimetallic complexes where a pair of 3 N+O four-coordinate metal planes are helically distorted and the central 2,2'-bipyrrole subunit adopts a cis or trans conformation. X-ray crystallographic analysis of the bisCu complex revealed a closed form with a cis-2,2'-bipyrrole subunit and an open form with a trans-2,2'-bipyrrole subunit. The bisPd complexes took a closed form both in the solid state and in solution. They are regarded as single helicates of two turns and the energy barrier for the interchange between an M helix and a P helix was remarkably influenced by the bulky 3,3'-substituent of the central 2,2'-bipyrrole subunit. Although the bisNi complexes adopt a closed form in the solid state, they exist as a homohelical open C2 -symmetric form or a heterohelical open Ci -symmetric form in solution. A theoretical study suggested that the closed form of 1 aPd was stabilized by the Pd-Pd interaction. Compound 1 aPd was reversibly oxidized by one electron at 0.14 V versus ferrocene/ferrocenium (Fc/Fc+ ) and this oxidized species showed Vis/NIR absorption bands at λ=767 and 1408 nm.
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Affiliation(s)
- Chaolu Eerdun
- School of Pharmaceutical Science, Inner Mongolia Medical University, Jinshan Economic & Technology Development District, Hohhot, 010100, P.R. China
| | - Thi Hien Thuy Nguyen
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Takuya Okayama
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Satoshi Hisanaga
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Jun-Ichiro Setsune
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
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Yagi S, Matsunaga T, Hamakubo K, Nakazumi H. Novel freebase and zinc bilinone dimers with optically active peripheral groups. Synthesis and application to chiral nematic induction in a nematic mesophase. RESEARCH ON CHEMICAL INTERMEDIATES 2009. [DOI: 10.1007/s11164-009-0078-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Yagi S, Hamakubo K, Ikawa S, Nakazumi H, Mizutani T. Homohelicity-enriched zinc bilinone dimers with chiral aliphatic spacers. Synthesis and application to chiral induction of a nematic liquid crystal. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.08.076] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wood TE, Thompson A. Advances in the chemistry of dipyrrins and their complexes. Chem Rev 2007; 107:1831-61. [PMID: 17430001 DOI: 10.1021/cr050052c] [Citation(s) in RCA: 501] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tabitha E Wood
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, B3H 4J3, Canada
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