Topic
Clathrochelate
About: Clathrochelate is a research topic. Over the lifetime, 178 publications have been published within this topic receiving 3859 citations.
Papers published on a yearly basis
Papers
1 Jan 1979
TL;DR: In this article, the authors propose a method for the synthesis of Macrocyclic Compound and Synthesis of MacroCycle Complexes (SCC) using a 2,6-Pyridyl Group (P2S2).
Abstract: 1. General Introduction.- 1. Introductory Comments.- 2. General Comments.- 2.1. Definition of a Macrocyclic Compound.- 2.2. Historical Background.- 2.3. Abbreviations of Macrocyclic Compounds.- 2.4. Units.- 2.5. Chapter Layout.- References.- 2. Synthesis of Macrocyclic Complexes.- 1. Introduction.- 2. Tridentate Ligands.- 3. Tetradentate Ligands.- 3.1. N4 Donor Atoms.- 3.2. N2O2 Donor Atoms.- 3.3. N2S2 Donor Atoms.- 3.4. S4 Donor Atoms.- 3.5. P4 and P2S2 Donor Atoms.- 4. Pentadentate Ligands.- 5. Sexadentate Ligands.- 6. Binucleating Ligands.- 7. Clathrochelates.- 8. Conclusions.- References.- 3. Thermodynamics and Kinetics of Cation-Macrocycle Interaction.- 1. Introduction.- 2. Parameters Determining Cation Selectivity and Complex Stability.- 2.1. Relative Sizes of Cation and Ligand Cavity.- 2.2. Arrangement of Ligand Binding Sites.- 2.3. Type and Charge of Cation.- 2.4. Type of Donor Atom.- 2.5. Number of Donor Atoms.- 2.6. Substitution on the Macrocyclic Ring.- 2.7. Solvent.- 3. Macrocyclic Effect.- 3.1. Tetramines.- 3.2. Cyclic Polyethers.- 3.3. Solvation Effects.- 3.4. Mixed Donor Groups.- 3.5. Multiple Juxtapositional Fixedness.- 3.6. Cryptate Effect.- 3.7. Summary.- 4. Table of Thermodynamic Data.- 5. Kinetics.- 5.1. Antibiotic Macrocycles.- 5.2. Cyclic Polyethers.- 5.3. Macrobicyclic Ligands.- References.- 4. Structural Aspects.- 1. Introduction.- 1.1. Scope and Organization.- 1.2. Order of Tabulation.- 2. Class 1: Cyclic Amines-Saturated Polyaza Macrocycles.- 2.1. Introduction.- 2.2. Configurations and Conformations of Coordination Cyclic Tetramines.- 2.3. Metal-Ion-Nitrogen Distances.- 2.4. Substituents on the Macrocycle.- 2.5. Chelate Angles.- 2.6. Listing of Structures of Compounds of Cyclic Amines.- 3. Class 2: Cyclic Imines and Cyclic Amine-Imines (Unsaturated Polyaza Macrocycles with all Nitrogen Atoms Coordinated).- 3.1. Discussion of Structures.- 3.2. Conformation of Macrocycles.- 3.3. Substituents on the Macrocycle.- 3.4. Metal Ion-Nitrogen Distances.- 3.5. Listing of Reported Structures of Cyclic Imine and Cyclic Amine-Imine Compounds.- 4. Class 3: Macrocycles Including a 2,6-Pyridyl Group.- 4.1. Discussion of Structures.- 4.2. Listing of Reported Structures of Compounds of Macrocycles Including a 2,6-Pyridyl Group.- 5. Class 4: Tetraazamacrocycles with 2-Imino(or 2-amido)-benzaldimine Chelate Rings.- 5.1. Discussion of Structures.- 5.2. Listing of Structures of Tetraazamacrocycles with l-Imino(or l-amido)-2-aldiminobenzene Chelate Rings (o-Iminobenzaldimine and o-Amidobenzaldimine Derivatives).- 6. Class 5: Dibenzo[b,i]-l,4,8,11-tetraazacyclotetradec-2,4,6,9,11-hexaenato(2-) Compounds.- 6.1. Discussion of Structures.- 6.2. Listing of Structures of Bzo2[14]hexaenato(2-)N4 Compounds.- 7. Class 6: Cyclic Hydrazines and Hydrazones.- 7.1. Discussion of Structures.- 7.2. Listing of Structures of Cyclic Hydrazine and Hydrazone Compounds.- 8. Class 7: Cyclic Tetraethers and Tetrathiaethers (Tetraoxo- and Tetrathiamacrocycles).- 8.1. Discussion of Structures.- 8.2. Listing of Structures of Tetraoxa- and Tetrathiamacrocycles.- 9. Class 8: Macrocycles with More Than One Type of Heteroatom.- 9.1. Discussion of Structures.- 9.2. Listing of Structures of Compounds.- 10. Class 9: Binucleating Macrocycles.- 10.1. Discussion of Structures.- 10.2. Listing of Structures of Binucleating Macrocycles.- 11. Class 10: Cyclic Phosphazenes.- 11.1. Discussion of Structures.- 11.2. Listing of Structures of Cyclic Phosphazene Compounds.- 12. Class 11: Clathrochelates.- 12.1. Discussion of Structures.- 12.2. Listing of Structures of Clathrochelate Compounds.- 13. Conclusion.- References.- 5. Ligand Field Spectra and Magnetic Properties of Synthetic Macrocyclic Complexes.- 1. Introduction.- 2. Nickel Complexes.- 2.1. Nickel(II) Macrocyclic Complexes.- 2.2. Macrocyclic Complexes of Nickel(I) and Nickel(III).- 3. Copper Complexes.- 3.1. Macrocyclic Copper(II) Complexes.- 3.2. Magnetic Interactions in Binuclear Macrocyclic Copper Complexes.- 3.3. Macrocyclic Complexes of Copper(I) and Copper(III).- 4. Cobalt Complexes.- 4.1. Cobalt(II) Macrocyclic Complexes.- 4.2. Macrocyclic Cobalt(III) Complexes.- 4.3. Cobalt(I) Macrocyclic Complexes.- 5. Iron Complexes.- 5.1. Low-Spin (S = 0) Iron(II) Macrocycles.- 5.2. High-Spin (S = 2) Iron(II) Macrocycles.- 5.3. Intermediate Spin (S = 1) Iron(II) Macrocycles.- 5.4. Low-Spin (S = 1/2) Iron(III) Macrocycles.- 5.5. High-Spin (5 = 5/2) and Intermediate-Spin (S = 3/2) Iron(III) Macrocycles.- 5.6. Other Iron-Containing Macrocycles.- 6. Manganese Complexes.- 6.1. Macrocyclic Complexes of Manganese(II).- 6.2. Macrocyclic Complexes of Manganese(III).- References.- 6. Chemical Reactivity in Constrained Systems.- 1. Introduction.- 2. Predominantly Metal-Centered Reactions.- 2.1. Coordinative Lability.- 2.2. Oxidation-Reduction Reactions of Simple Stoichiometry.- 3. Reactions of the Macrocyclic Ligands.- 3.1. Oxidative Dehydrogenations..- 3.2. Hydrogenation.- 3.3. Substitutions into the Macrocyclic Ligand.- 3.4. N-Alkylations.- 3.5. Additions.- 4. Reactions Involving Free Radicals, Unusual Oxidation States, and Excited States.- 4.1. Free Radical Reactions.- 4.2. Complexes Containing Metals in Unusual Oxidation States.- 4.3. Photochemical Reactions.- 4.4. Photochemistry of Cobalt-Alkyl Complexes.- References.- 7. Metal Complexes of Phthalocyanines.- 1. Introduction.- 2. Molecular Structure.- 3. Electronic Structure.- 4. Spectral Properties.- 5. Synthesis of New Derivatives.- 6. Redox Reactions.- 7. Aggregation of Complexes.- 8. Chromium Complexes.- 9. Manganese Complexes.- 10. Iron Complexes.- 11. Cobalt Complexes.- 12. Group IV Metal Complexes.- 13. Catalytic Activity.- 14. Comparison of Chemistry of Chromium, Manganese, Iron, and Cobalt Complexes.- References.- 8. Coordination Chemistry of Porphyrins.- 1. Introduction.- 2. Synthesis.- 3. Structure.- 4. Reactions.- 5. Chlorins and Corrins.- References.- 9. Physicochemical Studies of Crown and Cryptate Complexes.- 1. Introduction.- 2. Synthetic Methods.- 2.1. Crown Polyethers.- 2.2. [2]-Cryptands.- 2.3. [3]- and [4]-Cryptands.- 3. Metal-Cation Complexes: Preparation and Structure.- 3.1. Monocyclic Ligands (Crowns).- 3.2. Macropolycyclic Ligands (Cryptands).- 4. Complexes in Solutions: Experimental Techniques.- 4.1. General Considerations.- 4.2. Electrochemical Techniques.- 4.3. Spectroscopic Techniques.- 4.4. Extraction Studies.- 4.5. Calorimetric Techniques.- 4.6. Relaxation Techniques.- 5. Conclusion.- References.- 10. Natural-Product Model Systems.- 1. Introduction.- 1.1. Model Systems-Criticisms, Objectives, and Definitions.- 1.2. Importance of X-Ray Structural Analyses.- 1.3. Evolution of Models.- 2. Macrocyclic Complexes as Models.- 2.1. Macrocyclic Ethers and Thiaethers in Model Systems.- 2.2. Synthetic Tetraazamacrocyclic Systems.- 2.3. Fundamental Studies of Synthetic Macrocyclic Ligand Complexes.- 3. Modeling of Heme Proteins.- 3.1. Studies Involving Metals Other than Iron.- 3.2. Iron(II) Carbon Monoxide Complexes.- 3.3. Dioxygen Complexes.- 3.4. Cytochromes.- 4. Binuclear Systems.- 4.1. Cofacial Diporphyrins.- 4.2. Unsymmetrical Binuclear Systems.- 5. Comments on Vitamin B12 and Related Inorganic Systems.- References.
707 citations
TL;DR: Electrochemical investigation of a boron-capped tris(glyoximato)cobalt clathrochelate complex in the presence of acid reveals that the catalytic activity toward hydrogen evolution results from an electrodeposition of cobalt-containing nanoparticles on the electrode surface at a modest cathodic potential.
Abstract: Electrochemical investigation of a boron-capped tris(glyoximato)cobalt clathrochelate complex in the presence of acid reveals that the catalytic activity toward hydrogen evolution results from an electrodeposition of cobalt-containing nanoparticles on the electrode surface at a modest cathodic potential. The deposited particles act as remarkably active catalysts for H2 production in water at pH 7.
186 citations
TL;DR: Investigation of the electrochemical activity of the boron-capped tris(glyoximato) cobalt complexes towards hydrogen evolution and the synthesis and characterization of three clathrochelate Co complexes together with their involvement in an electrocatalytic hydrogen-forming reaction in solution are reported.
Abstract: Developing a hydrogen-based economy is one possible scenario to reach a sustainable energy development and also to put ourselves on a path to cut the carbon emissions for obvious climate issues. However, several inherent problems must be overcome, such as production, storage, transport, and efficiency. 3] We are involved in research towards developing metal complexes for the electrocatalysis of hydrogen production. The challenge is to replace the expensive and limited platinum metal with non-noble metal complexes. A bioinorganic approach to tackling this problem wherein metal complexes, based mainly on iron, are designed to mimic the catalytic site of the Fe-hydrogenases, in the hope of simulating their reactivity patterns, has attracted much attention. A general trend in the electrocatalytic activity of these complexes is high overpotential. More classical metal coordination complexes for electrocatalysis have also been reported to show interesting activities towards hydrogen evolution. Among these examples are the difluoroboryl annulated bis(glyoximato) cobalt derivatives studied by Espenson and Chao. In recent years several groups, including ourselves, have demonstrated that this family of complexes can perform electrocatalysis of proton reduction in organic media. Hexacoordinated cobalt complexes have also been reported to act as catalysts for proton reduction. However, no clear-cut mechanism is known for the catalytic activity of these complexes, which was evidenced only on a mercury electrode. In boron-capped tris(glyoximato) cobalt complexes, the metal ion is both coordinatively saturated and encapsulated by a single macrobicyclic ligand. These coordination compounds are classified as clathrochelate complexes, in which the metal ion is locked in a close-knit structure, inhibiting ligand exchange in the more labile oxidation states of the encapsulated metal ion, and, in turn, explaining why the chemical activity of this family of complexes has been particularly elusive. We have been interested in investigating the electrochemical activity of the boron-capped tris(glyoximato) cobalt complexes towards hydrogen evolution. Herein, we report on the synthesis and characterization of three clathrochelate Co complexes [1], [2], and [3] (Figure 1) together with their involvement in an electrocatalytic hydrogen-forming reaction in solution. X-ray crystallographic data for [1] and for a derivative Co complex [4] are also discussed.
126 citations
TL;DR: The clathrochelates obtained have been characterized both on the basis of elemental analysis, FAB and PD mass spectrometry, IR, UV-vis, 57Fe Mössbauer, and NMR spectroscopies and crystallographically (compounds 3, 4, 6, 7, and 11).
Abstract: Template condensation on iron(II) ion of dichloroglyoxime (H2C12Gm) with (C6H5O)3, n-C4H9B(O-n-C4H9)2, and BF3.O(C2H5)2 in CH3NO2 afforded reactive clathrochelate precursors Fe(C12Gm)3(BC6H5)2 (2), Fe(C12Gm)3(B-n-C4H9)2 (3), and Fe(C12Gm)3(BF)2 (4). A series of triribbed-functionalized clathrochelate dioximates have been synthesized. Reaction of 2 with C6H5SH/K2CO3 and CH3SH/t-C4H9OK in 1,4-dioxane and THF afforded Fe((C6H5S)2Gm)3(BC6H5)2 (5) and Fe((CH3S)2Gm)3(BC6H5)2 (6). Reaction of 3 with C6H5OK in THF afforded Fe((C6H5O)2Gm)3(B-n-C4H9)2 (7). Condensation of 3 with bis(2-(o-oxyphenoxy))diethyl ether in THF afforded di- and tricrown etheric Fe(CwGm)2(C12Gm)(Bn-C4H9)2 (8) and Fe(CwGm)3(B-n-C4H9)2 (9) clathrochelates. Condensation of 3 with 3,5-dithiaoctane-1,8-dithiol/Cs2CO3 in DMF afforded the thiocrown etheric Fe((12anS4)Gm)3(BC6H5)2 complex (10). Reaction of 2 with n-butylamine in DMF resulted in the tetrasubstituted Fe((n-C4H9NH)2Gm)2(C12Gm)(BC6H5)2 clathrochelate (11). The clathrochelates obtained have been characterized both on the basis of elemental analysis, FAB and PD mass spectrometry, IR, UV-vis, 57Fe Mossbauer, and NMR spectroscopies and crystallographically (compounds 3, 4, 6, 7, and 11). An encapsulated iron(II) ion in a distorted trigonal-prismatic environment of six nitrogen atoms of the macrobicyclic ligand was found to be in a low-spin state. The cyclic voltammograms for the complexes 2-11 show irreversible oxidation waves assignable to Fe3+/Fe2+ couples. The correlation of E1/2 for these couples with Hammet sigma para constants for substituents in dioximate fragments has been demonstrated.
105 citations
TL;DR: Specially designed hexachlorine-containing cobalt(II) tris-dioximate clathrochelates were found to efficiently electrocatalyze the production of molecular hydrogen from H(+) ions without the overpotential of this process.
90 citations
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