Co-ordination chemistry of iodine(I) with tetraazamacrocycles or monodentate ligands. Comparisons with bromine(I) and with some d-block metals

Hua, Wang Shi; Ajiboye, Sarah I.; Haining, G.; McGhee, Laurence; Peacock, Robert D.; Peattie, Gordon; Siddique, Rana M.; Winfield, John M.

doi:10.1039/dt9950003837

Cited by 8 publications

(2 citation statements)

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“…Therefore, we set out to (1) exemplify/expand the versatility of macrocyclic ligands, previously shown to facilitate other catalytic transformations, ,,,, to C–C chemistry to produce 2-phenylpyrrole for the first time and (2) identify properties of such an iron catalyst that result in increased catalytic yields. Modifications to tetra-azamacrocyclic ligands abound in the literature and are known to impact electronics and structural features of metal complexes. ,,,,,− For the study described herein, [Fe 3+ L1(Cl) 2 ] + , [Fe 3+ L4(Cl) 2 ] + , [Fe 2+ L5(Cl)] + , [Fe 2+ L6(Cl) 2 ] , [Fe 3+ L7(Cl) 2 ] + , [Fe 3+ L8(Cl) 2 ] + , [Fe 2+ L9(Cl)] + , and [Fe 2+ L10(Cl)] + (Figure ) at 10% loading resulted in a catalytic yields ranging from 19 to 81% (Table ). Given that each catalyst was isolated and characterized prior to the catalytic studies, the inorganic properties of the iron catalysts could be compared for correlations to catalytic yield.…”

Section: Results and Discussionmentioning

confidence: 99%

Increase of Direct C–C Coupling Reaction Yield by Identifying Structural and Electronic Properties of High-Spin Iron Tetra-azamacrocyclic Complexes

et al. 2018

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Macrocyclic ligands have been explored extensively as scaffolds for transition metal catalysts for oxygen and hydrogen atom transfer reactions. C-C reactions facilitated using earth abundant metals bound to macrocyclic ligands have not been well-understood but could be a green alternative to replacing the current expensive and toxic precious metal systems most commonly used for these processes. Therefore, the yields from direct Suzuki-Miyaura C-C coupling of phenylboronic acid and pyrrole to produce 2-phenylpyrrole facilitated by eight high-spin iron complexes ([FeL1(Cl)], [FeL4(Cl)], [FeL5(Cl)], [FeL6(Cl)], [FeL7(Cl)], [FeL8(Cl)], [FeL9(Cl)], and [FeL10(Cl)]) were compared to identify the effect of structural and electronic properties on catalytic efficiency. Specifically, catalyst complexes were compared to evaluate the effect of five properties on catalyst reaction yields: (1) the coordination requirements of the catalyst, (2) redox half-potential of each complex, (3) topological constraint/rigidity, (4) N atom modification(s) increasing oxidative stability of the complex, and (5) geometric parameters. The need for two labile cis-coordination sites was confirmed based on a 42% decrease in catalytic reaction yield observed when complexes containing pentadentate ligands were used in place of complexes with tetradentate ligands. A strong correlation between iron(III/II) redox potential and catalytic reaction yields was also observed, with [FeL6(Cl)] providing the highest yield (81%, -405 mV). A Lorentzian fitting of redox potential versus yields predicts that these catalysts can undergo more fine-tuning to further increase yields. Interestingly, the remaining properties explored did not show a direct, strong relationship to catalytic reaction yields. Altogether, these results show that modifications to the ligand scaffold using fundamental concepts of inorganic coordination chemistry can be used to control the catalytic activity of macrocyclic iron complexes by controlling redox chemistry of the iron center. Furthermore, the data provide direction for the design of improved catalysts for this reaction and strategies to understand the impact of a ligand scaffold on catalytic activity of other reactions.

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Section: Results and Discussionmentioning

confidence: 99%

Increase of Direct C–C Coupling Reaction Yield by Identifying Structural and Electronic Properties of High-Spin Iron Tetra-azamacrocyclic Complexes

et al. 2018

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“…[15] Attempts to grow suitable crystals of 5 for a Xray crystal structure determination failed, but saturated tol- [16] Complex 6 is not soluble in unreactive solvents and its IR (KBr) spectrum is essentially identical to that of 4.…”

Section: Resultsmentioning

confidence: 99%

Iodine Attack on the Metalloligand [{Ti(η⁵‐C₅Me₅)(μ‐NH)}₃(μ₃‐N)]: Surprising Formation of the [Ti₃(η⁵‐C₅Me₅)₃I₂(μ‐NH)₃(NH₃)]⁺ Cation

et al. 2006

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The reactivity of the trinuclear imido‐nitrido complex [{Ti(η5‐C5Me5)(μ‐NH)}3(μ3‐N)] (1) and derivatives thereof withiodine has been investigated. Treatment of the indium(I)adduct [IIn{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}] (2) with I2 (1 equiv.) in benzene afforded the indium(III) complex [I3In{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}] (3), but with excess of iodine the precipitation of orange crystals of the ionic complex [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)][InI4] (4) takes place. Analogous treatment of the metalloligand 1 with I2 in toluene gave initially the iodine(I) derivative [I{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}][I3] (5). Surprisingly, toluene solutions of 5 at room temperature produced crystals of the ionic complex [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)][I3]·C7H8 (6·C7H8). The trinuclear titanium cation [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)]+ of complexes 4 and 6 has been structurally characterized by a combination of X‐ray and DFT studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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Chlorine, Bromine, Iodine, & Astatine: Inorganic ChemistryBased in part on the article Chlorine, Bromine, Iodine, & Astatine: Inorganic Chemistry by Jacob Shamir which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Lang

2005

Encyclopedia of Inorganic Chemistry

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This chapter summarizes the occurrences, atomic structures, and molecular properties of the elements of group 17, chlorine, bromine, iodine, and astatine. The charge‐transfer complexes of halogens with different inorganic or organic compounds are outlined. The interhalogen compounds, especially those of polyiodides, are discussed with respect to their preparation and their structure varieties. The halogen oxides such as halogen oxide cations, halogen oxide fluorides, oxoacids and oxoacid salts, and halogen derivatives of oxoacids are discussed. Finally, organic polyvalent halogen derivatives, mainly including those of iodine (I), iodine (III), and iodine (V), are mentioned.

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Co-ordination chemistry of iodine(I) with tetraazamacrocycles or monodentate ligands. Comparisons with bromine(I) and with some d-block metals

Cited by 8 publications

References 29 publications

Increase of Direct C–C Coupling Reaction Yield by Identifying Structural and Electronic Properties of High-Spin Iron Tetra-azamacrocyclic Complexes

Increase of Direct C–C Coupling Reaction Yield by Identifying Structural and Electronic Properties of High-Spin Iron Tetra-azamacrocyclic Complexes

Iodine Attack on the Metalloligand [{Ti(η⁵‐C₅Me₅)(μ‐NH)}₃(μ₃‐N)]: Surprising Formation of the [Ti₃(η⁵‐C₅Me₅)₃I₂(μ‐NH)₃(NH₃)]⁺ Cation

Chlorine, Bromine, Iodine, & Astatine: Inorganic ChemistryBased in part on the article Chlorine, Bromine, Iodine, & Astatine: Inorganic Chemistry by Jacob Shamir which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

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Co-ordination chemistry of iodine(I) with tetraazamacrocycles or monodentate ligands. Comparisons with bromine(I) and with some d-block metals

Cited by 8 publications

References 29 publications

Increase of Direct C–C Coupling Reaction Yield by Identifying Structural and Electronic Properties of High-Spin Iron Tetra-azamacrocyclic Complexes

Increase of Direct C–C Coupling Reaction Yield by Identifying Structural and Electronic Properties of High-Spin Iron Tetra-azamacrocyclic Complexes

Iodine Attack on the Metalloligand [{Ti(η5‐C5Me5)(μ‐NH)}3(μ3‐N)]: Surprising Formation of the [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)]+ Cation

Chlorine, Bromine, Iodine, & Astatine: Inorganic ChemistryBased in part on the article Chlorine, Bromine, Iodine, & Astatine: Inorganic Chemistry by Jacob Shamir which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

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Iodine Attack on the Metalloligand [{Ti(η⁵‐C₅Me₅)(μ‐NH)}₃(μ₃‐N)]: Surprising Formation of the [Ti₃(η⁵‐C₅Me₅)₃I₂(μ‐NH)₃(NH₃)]⁺ Cation