SYNTHESIZE AND CHARACTERIZATION OF MANGANESE(III)-SALEN-4,4'- BIPYRIDINE COMPLEX COMPOUNDS WITH THE PERCHLORATE AND HEXAFLUOROPHOSPHATE ANIONS AS SUPEROXIDE DISMUTASE MIMICS

Manganese(III)-salen complexes have been extensively studied because they can used as catalysts on the asymmetric epoxidation of olefins, which is a very important reaction in the organic chemistry. In addition, manganese(III)-salen complexes also have the potential as molecular magnet materials due...

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Main Author: Deawati, Yusi
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Language:Indonesia
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Institution: Institut Teknologi Bandung
Language: Indonesia
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institution Institut Teknologi Bandung
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country Indonesia
Indonesia
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topic Kimia
spellingShingle Kimia
Deawati, Yusi
SYNTHESIZE AND CHARACTERIZATION OF MANGANESE(III)-SALEN-4,4'- BIPYRIDINE COMPLEX COMPOUNDS WITH THE PERCHLORATE AND HEXAFLUOROPHOSPHATE ANIONS AS SUPEROXIDE DISMUTASE MIMICS
description Manganese(III)-salen complexes have been extensively studied because they can used as catalysts on the asymmetric epoxidation of olefins, which is a very important reaction in the organic chemistry. In addition, manganese(III)-salen complexes also have the potential as molecular magnet materials due to unpaired electrons in the d orbital. In the bioinorganic, this complex can also be a model in biochemical systems such as metalloenzymes and proteins,i.e. among others, these complexes can be function as a synthetic or superoxide dismutase enzyme mimics (SODm) which can inhibit the effects of aging. Modification of salen ligands in the manganese(III)-salen complexes to study their mSOD activities has been carried out, either through substitution of aromatic rings or aromatic bridge in the salen ligand, but the effect is small. In terms of structure, the manganese(III)-salen complexes structure was influenced by the counter anion that added during the synthesis of these complexes.The previous results reported that the manganese(III)-salen complex containing the perchlorate (ClO –) anion have the dimer structure, while the polymeric structure was shown by the manganese(III)-salen complex containing the hexafluorophosphate (PF –) anion. Beside that, the complex structures also affected by the type of bridging ligand. In this study, three new of manganese(III)-salen complexes were successfully synthesized, i.e: [MnIII(salen)(4,4'-bpy)Cl] (1), [{MnIII(salen)ClO4}2(?-4,4'-bpy)] . . (2), and {[MnIII(salen)(?-4,4'-bpy)]PF6}n 1.5nMeOH 0.5nH2O (3). The bridging ligand used in the formation of these complexes was 4,4’-bipyridine (4,4’-bpy). In the complex (2) and (3), two manganese ions were bridged by the 4,4’-bpy ligand. The influence of counter anions was also observed on the structure of these complexes. In the presence of perchlorate, the complex (2) has a dimeric structure – with the ClO4 anion was coordinated to the manganese(III) ion, while the third complex (3) has a polymeric structure with the PF – the manganese(III) ion. anion that uncoordinated to The complex (1) is a compound having molecular formula [MnIII(salen) (4,4'-bpy)Cl], that determined from the results of the C, H, and N of the elemental analysis of its complex solids compared with the theoretical content in parentheses, namely C = 59.84% (60.89%); H = 4.32% (4.32%); and N = 10.25% (10.92%). This result is also supported by very low molar conductivity of the complex (1), i.e. 0.17 mS.cm2.mol-1, indicating that the complex is non ionic. The dimeric complex of [{MnIII(salen)ClO4}2(?-4,4'-bpy)] (2) was crystallized in a triclinic system and a space group of P?. From the crystallographic data, the complex contains Mn(III) metal ions which have a d4 configuration and exhibit Jahn-Teller distortion, in which the bond in the axial direction is longer than the bond in the equatorial plane. In the equatorial plane of the complex (2), the two N and O donor atoms in the salen ligand coordinated to the central ion of Mn(III) of each monomer, with the bond length of Mn(1)–O(1)salen = 1.874(2) Å; Mn(1)–O(2)salen = 1.876(2) Å; Mn(1)–N(1)salen = 1.978(2) Å; and Mn(1)–N(2)salen = 1.968(2) Å, while in the axial direction, the 4,4'-bpy bridging ligand connects the two central Mn(III) ions of each monomer with the bond length of Mn(1)–N(3)?-4,4'-bpy = 2.296(2) Å, and coordinate one of the O donor atom from the – ClO4 ligand to the two ends of the dimer molecule, with the bond length of Mn(1)–O(3)ClO3 = 2.433(2) Å. The crystallography of the complex crystal of the {[MnIII(salen)(?-4,4'- . . bpy)]PF6}n 1.5nMeOH 0.5nH2O (3) shows that this complex has a polymeric structure arranged in a triclinic crystal system and a space group of P?. As expected, the 4,4'-bpy ligands form bridging ligand in the both axial positions of the manganese(III)-salen complexes monomer to form polymeric chains. The four salen donor atoms occupy the equatorial plane, with Mn–O bond lengths of 1.870(2) and 1.871(2) Å, and Mn–N with the bond lengths of 1.972(2) and 1.973(2) Å. The Mn–N bond in the both axial sides of the 4,4'-bpy ligand bridge, yielded the distance of 2.368(2) and 2.372(2) Å, respectively. The complex (3) is a – cationic complex with the PF6 as a counter anion and crystallized along with methanol and water solvent molecules. These manganese(III)-salen complexes have different the mSOD activity, which was affected by their stuctures. The mSOD activity was measured based on the IC50 value. The IC50 values for the complex (2) and (3) were 2.0 ?M and 1.6 ?M, respectively. The mSOD activities for the dimeric and polymeric structure were higher than the monomeric structure of precursor of [MnIII(salen)((H2O)Cl] and complex (1) which shown by the IC50 of 2.5 and 3.7 ?M, respectively. The increasing of mSOD activity in the dimeric structure of the complex (2) and the polymeric strucutre of the complex (3) was caused by the electrons transfer proccesses from the superoxide radical to the active center of the Mn(III) ion and vice versa become easier than in the monomeric structure of the precursor complex and the complex (1). This is observed by the MnIII/MnII redox cycles in the cyclic voltammetry analysis, in the form of a pair of quasi-reversible redox peaks on the voltammogram of the complex (2) and (3), with the redox potential values of E1/2 = 0.55 and 0.64 V vs NHE, respectively.
format Theses
author Deawati, Yusi
author_facet Deawati, Yusi
author_sort Deawati, Yusi
title SYNTHESIZE AND CHARACTERIZATION OF MANGANESE(III)-SALEN-4,4'- BIPYRIDINE COMPLEX COMPOUNDS WITH THE PERCHLORATE AND HEXAFLUOROPHOSPHATE ANIONS AS SUPEROXIDE DISMUTASE MIMICS
title_short SYNTHESIZE AND CHARACTERIZATION OF MANGANESE(III)-SALEN-4,4'- BIPYRIDINE COMPLEX COMPOUNDS WITH THE PERCHLORATE AND HEXAFLUOROPHOSPHATE ANIONS AS SUPEROXIDE DISMUTASE MIMICS
title_full SYNTHESIZE AND CHARACTERIZATION OF MANGANESE(III)-SALEN-4,4'- BIPYRIDINE COMPLEX COMPOUNDS WITH THE PERCHLORATE AND HEXAFLUOROPHOSPHATE ANIONS AS SUPEROXIDE DISMUTASE MIMICS
title_fullStr SYNTHESIZE AND CHARACTERIZATION OF MANGANESE(III)-SALEN-4,4'- BIPYRIDINE COMPLEX COMPOUNDS WITH THE PERCHLORATE AND HEXAFLUOROPHOSPHATE ANIONS AS SUPEROXIDE DISMUTASE MIMICS
title_full_unstemmed SYNTHESIZE AND CHARACTERIZATION OF MANGANESE(III)-SALEN-4,4'- BIPYRIDINE COMPLEX COMPOUNDS WITH THE PERCHLORATE AND HEXAFLUOROPHOSPHATE ANIONS AS SUPEROXIDE DISMUTASE MIMICS
title_sort synthesize and characterization of manganese(iii)-salen-4,4'- bipyridine complex compounds with the perchlorate and hexafluorophosphate anions as superoxide dismutase mimics
url https://digilib.itb.ac.id/gdl/view/34432
_version_ 1821996740287397888
spelling id-itb.:344322019-02-08T14:42:59ZSYNTHESIZE AND CHARACTERIZATION OF MANGANESE(III)-SALEN-4,4'- BIPYRIDINE COMPLEX COMPOUNDS WITH THE PERCHLORATE AND HEXAFLUOROPHOSPHATE ANIONS AS SUPEROXIDE DISMUTASE MIMICS Deawati, Yusi Kimia Indonesia Theses manganese(III)-salen, 4,4'-bpy, ClO4– ligand, PF6 , dimeric, polymeric INSTITUT TEKNOLOGI BANDUNG https://digilib.itb.ac.id/gdl/view/34432 Manganese(III)-salen complexes have been extensively studied because they can used as catalysts on the asymmetric epoxidation of olefins, which is a very important reaction in the organic chemistry. In addition, manganese(III)-salen complexes also have the potential as molecular magnet materials due to unpaired electrons in the d orbital. In the bioinorganic, this complex can also be a model in biochemical systems such as metalloenzymes and proteins,i.e. among others, these complexes can be function as a synthetic or superoxide dismutase enzyme mimics (SODm) which can inhibit the effects of aging. Modification of salen ligands in the manganese(III)-salen complexes to study their mSOD activities has been carried out, either through substitution of aromatic rings or aromatic bridge in the salen ligand, but the effect is small. In terms of structure, the manganese(III)-salen complexes structure was influenced by the counter anion that added during the synthesis of these complexes.The previous results reported that the manganese(III)-salen complex containing the perchlorate (ClO –) anion have the dimer structure, while the polymeric structure was shown by the manganese(III)-salen complex containing the hexafluorophosphate (PF –) anion. Beside that, the complex structures also affected by the type of bridging ligand. In this study, three new of manganese(III)-salen complexes were successfully synthesized, i.e: [MnIII(salen)(4,4'-bpy)Cl] (1), [{MnIII(salen)ClO4}2(?-4,4'-bpy)] . . (2), and {[MnIII(salen)(?-4,4'-bpy)]PF6}n 1.5nMeOH 0.5nH2O (3). The bridging ligand used in the formation of these complexes was 4,4’-bipyridine (4,4’-bpy). In the complex (2) and (3), two manganese ions were bridged by the 4,4’-bpy ligand. The influence of counter anions was also observed on the structure of these complexes. In the presence of perchlorate, the complex (2) has a dimeric structure – with the ClO4 anion was coordinated to the manganese(III) ion, while the third complex (3) has a polymeric structure with the PF – the manganese(III) ion. anion that uncoordinated to The complex (1) is a compound having molecular formula [MnIII(salen) (4,4'-bpy)Cl], that determined from the results of the C, H, and N of the elemental analysis of its complex solids compared with the theoretical content in parentheses, namely C = 59.84% (60.89%); H = 4.32% (4.32%); and N = 10.25% (10.92%). This result is also supported by very low molar conductivity of the complex (1), i.e. 0.17 mS.cm2.mol-1, indicating that the complex is non ionic. The dimeric complex of [{MnIII(salen)ClO4}2(?-4,4'-bpy)] (2) was crystallized in a triclinic system and a space group of P?. From the crystallographic data, the complex contains Mn(III) metal ions which have a d4 configuration and exhibit Jahn-Teller distortion, in which the bond in the axial direction is longer than the bond in the equatorial plane. In the equatorial plane of the complex (2), the two N and O donor atoms in the salen ligand coordinated to the central ion of Mn(III) of each monomer, with the bond length of Mn(1)–O(1)salen = 1.874(2) Å; Mn(1)–O(2)salen = 1.876(2) Å; Mn(1)–N(1)salen = 1.978(2) Å; and Mn(1)–N(2)salen = 1.968(2) Å, while in the axial direction, the 4,4'-bpy bridging ligand connects the two central Mn(III) ions of each monomer with the bond length of Mn(1)–N(3)?-4,4'-bpy = 2.296(2) Å, and coordinate one of the O donor atom from the – ClO4 ligand to the two ends of the dimer molecule, with the bond length of Mn(1)–O(3)ClO3 = 2.433(2) Å. The crystallography of the complex crystal of the {[MnIII(salen)(?-4,4'- . . bpy)]PF6}n 1.5nMeOH 0.5nH2O (3) shows that this complex has a polymeric structure arranged in a triclinic crystal system and a space group of P?. As expected, the 4,4'-bpy ligands form bridging ligand in the both axial positions of the manganese(III)-salen complexes monomer to form polymeric chains. The four salen donor atoms occupy the equatorial plane, with Mn–O bond lengths of 1.870(2) and 1.871(2) Å, and Mn–N with the bond lengths of 1.972(2) and 1.973(2) Å. The Mn–N bond in the both axial sides of the 4,4'-bpy ligand bridge, yielded the distance of 2.368(2) and 2.372(2) Å, respectively. The complex (3) is a – cationic complex with the PF6 as a counter anion and crystallized along with methanol and water solvent molecules. These manganese(III)-salen complexes have different the mSOD activity, which was affected by their stuctures. The mSOD activity was measured based on the IC50 value. The IC50 values for the complex (2) and (3) were 2.0 ?M and 1.6 ?M, respectively. The mSOD activities for the dimeric and polymeric structure were higher than the monomeric structure of precursor of [MnIII(salen)((H2O)Cl] and complex (1) which shown by the IC50 of 2.5 and 3.7 ?M, respectively. The increasing of mSOD activity in the dimeric structure of the complex (2) and the polymeric strucutre of the complex (3) was caused by the electrons transfer proccesses from the superoxide radical to the active center of the Mn(III) ion and vice versa become easier than in the monomeric structure of the precursor complex and the complex (1). This is observed by the MnIII/MnII redox cycles in the cyclic voltammetry analysis, in the form of a pair of quasi-reversible redox peaks on the voltammogram of the complex (2) and (3), with the redox potential values of E1/2 = 0.55 and 0.64 V vs NHE, respectively. text