Heterodinuclear metal complexes of phenol-based compartmental macrocycles

Ökawa, Hisashi; Furutachi, Hideki; Fenton, David E.

doi:10.1016/s0010-8545(97)00082-9

Cited by 279 publications

(106 citation statements)

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“…Compartment-type ligands, which have distinct coordination sites for different metal ions, are very useful for assembling such species. 6 In recent times, many heterometal complexes have been constructed by exploiting the complexation stability constants of different metal ions. Self-assembly driven syntheses of heterometallic systems have also been serendipitously discovered.…”

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confidence: 99%

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An Antiferromagnetically Coupled Heterometal Cu₆Fe Wheel

Saiki¹,

Yoshida²,

Hoshino

et al. 2017

Chem. Lett.

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A heterometal Cu 6 Fe wheel molecule, [Cu II 6 Fe III (HL) 6 -(OH) 2 (OCH 3 ) 4 ](NO 3 ) 3 ¢6H 2 O (1¢6H 2 O) (H 2 L = 1-(2-pyridine)-3-(2-pyrrole)acetylacetone) was synthesized by the one-pot reaction of H 2 L with copper and iron sources. X-ray structural analysis reveals that the heptanuclear wheel cluster consists of a central Fe(III) ion surrounded by six Cu(II) ions, linked through methoxo-and hydroxo-bridges. Cryomagnetic studies indicate intramolecular antiferromagnetic interactions were operative. Heterometal polynuclear complexes exhibit physical properties and functions derived from the electronic and magnetic interactions between their constituent transition metal ions, and the search for new compounds with novel properties and functions continues to be an important area of research.1 In the field of biomolecular chemistry, several enzyme models with heterometallic active sites have been investigated.2 It is thus critical to find effective synthetic methods for heterometal clusters in order to better understand the reaction mechanisms of these active sites. Likewise, in materials chemistry, intermetal electronic/magnetic interactions between different metal ions also lead to specific physical properties.3 Heterometal systems can offer a convenient route to designable single-molecule magnets as the magnetic characters of different metal ions can lead to favorable orbital interactions and spin alignment. 4 It is well-known that heterometal mixed-valence systems, such as cyanide-bridged Co-Fe compounds, show external stimuli induced electron-transfer-coupled spin transitions.5 Heterometal complexes are attractive targets in many areas of chemistry and, as a result, new approaches to their controlled-syntheses are needed. Compartment-type ligands, which have distinct coordination sites for different metal ions, are very useful for assembling such species. 6 In recent times, many heterometal complexes have been constructed by exploiting the complexation stability constants of different metal ions. Self-assembly driven syntheses of heterometallic systems have also been serendipitously discovered.7 With these points in mind, advanced synthetic methods should be explored by using appropriate polydentate ligands and reaction conditions. We investigated a range of alkoxo-bridged polynuclear metal clusters, such as homometal [Mn 13 22 These heterometal rings are intensively investigated because of their potential application as spin qubits in quantum computing.In this work, we focus on the asymmetric multidentate bridging ligand, 1-(2-pyridine)-3-(2-pyrrole)acetylacetone (H 2 L), and its complexation reactions with copper and iron sources have been investigated. Herein, the structure and magnetic properties of the obtained heptanuclear Cu 6 Fe wheel complex are reported.To a methanol solution (15 mL) of Cu(NO 3 ) 2 ¢3H 2 O (24.2 mg, 0.1 mmol) was added a methanol solution (10 mL) of H 2 L (21.4 mg, 0.1 mmol) with trimethylamine (27.6¯L, 0.2 mmol). The resulting brown solution was stirred and a methanol ...

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“…Herein, the structure and magnetic properties of the obtained heptanuclear Cu 6 Fe wheel complex are reported.…”

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An Antiferromagnetically Coupled Heterometal Cu₆Fe Wheel

Saiki¹,

Yoshida²,

Hoshino

et al. 2017

Chem. Lett.

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“…Several classes of macrocyclic ligands have been synthesized [3]. In the title crystal structure, the intramolecular hydrogen bonds involving the phenolic oxygens are of particular importance because the macrocyclic cation is stabilized by these bonds.…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of 7,15,23,31-tetramethyl-3,11,19,27-tetraazopentacyclo[ 27.16.1611.27.4.411.27.3.35.9.313.17.321.25.1.15.9.113.17.121.25]triaconta- 1(32),5,7,9(34),13,15,17(35),21,23,25(36),29(33),30-dodecaarene- 33,34,35,36-tetraol, C44H56N4O4

Yang¹

2010

Zeitschrift Für Kristallographie - New Crystal Structures

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C 44 H 56 N 4 O 4 ,monoclinic, C12/c1(no. 15), a =23.216(2) Å, b =14.0445(9) Å, c =13.064(1) Å, b =118.413(9)°, V =3746.5 Å 3 , Z =4,Rgt(F) =0.076, wRref (F 2 ) =0.186, T =293 K. Source of materialThe macrocyclic ligand H 2Lwas prepared as reported earlier [1]. Amethanol solution (30 mL) containing H 2L( 0.44 g, 1mmol) was heated to boiling and then slowly treated with amethanol solution (20 mL) of 4-methyl-2,6-diformyl (0.33 g, 2mmol). After stirring for 1h ,a no range precipitate was obtained. Then a amount of solid NaBH 4 was added to the solution. The solid material gradually went into solution, and ultimately an almost colorless solution was obtained over ap eriod of 0.5 h. This was filtered, and to the filtrate was added slowly 30 mL of water with stirring. The resulting solution was allowed to stand overnight, during which period the product separated out as colorless crystals. The product was collected by filtration and recrystallized from methanol/water (yield 35 %ormore). The product (0.077 g, 0.1 mmol) and Ni(OAc) 2. · . 6H 2 O(0.050 g, 0.2 mmol) were dissolved in DMF (5 mL) and water (5 mL). The mixture sealed in a 15 mL Teflon-lined stainless steel autoclave, and heated at 100°C for 4d ays under autogenous pressure. Afterward, the reaction system was gradually cooled to room temperature at ar ate of 10°C/h. Light green crystals were obtained in a34 . %yield. Experimental detailsAll Ha toms on Ca toms were generated geometrically and refined as riding atoms with d(C-H) =0.93 Å and U iso (H) =1.2 or 1.5 U eq (C). The hydroxy Ha tom were located from difference Fourier map and refined with U iso (H) =1 .5 U eq (O). The huge residual values are caused by the vibration of the terminal C21 and C22 atoms at room temperature. DiscussionRecently, the study of metal complexes with phenol-based macrocyclic compartmental ligands has become important in view of their significance as biomimetric catalysts in the process of oxygenation [2]. Several classes of macrocyclic ligands have been synthesized [3]. In the title crystal structure, the intramolecular hydrogen bonds involving the phenolic oxygens are of particular importance because the macrocyclic cation is stabilized by these bonds. The N···Odistances are in the range 2.738 (5) -3.04 (1) Å,while the O-H···Nangles vary between 135°and 140°,which indicates that the intramolecular hydrogen bonds are quite strong. The C-O and C-Nbond lengthes are in the range of 1.37 to 1.45 Å,respectively. The bond distances and bond angles are all in normal range.

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“…Among various derivatives of pyrazolone, 4-aminoantipyrine is significant owing to its willingly condensing property with various types of carbonyl compounds to obtain a variety of Schiff bases,which could be used in a number of major fields like biology and pharmaceutical industries [1][2] . The Schiff bases are more probable ligands in the formation of complexes with different metals due to its azomethine bond [3][4][5][6][7][8] . Much work have been reported from many fields on 4-aminoantipyrine,which act as precursor to prepare a large number of various transition metal complexes [9][10][11] .…”

Section: Introductionmentioning

confidence: 99%