Post-synthetic Mannich chemistry on metal-organic frameworks: system-specific reactivity and functionality-triggered dissolution: System-Specific Reactivity and Functionality-Triggered Dissolution

Harina Amer Hamzah, William Gee, Paul Raithby, Simon J Teat, Mary Mahon, Andrew Burrows

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2 Citations (Scopus)

Abstract

The Mannich reaction of the zirconium MOF [Zr6O4(OH)4(bdc-NH2)6] (UiO-66-NH2, bdc-NH2=2-amino-1,4-benzenedicarboxylate) with paraformaldehyde and pyrazole, imidazole or 2-mercaptoimidazole led to post-synthetic modification (PSM) through C−N bond formation. The reaction with imidazole (Him) goes to completion whereas those with pyrazole (Hpyz) and 2-mercaptoimidazole (HimSH) give up to 41 and 36 % conversion, respectively. The BET surface areas for the Mannich products are reduced from that of UiO-66-NH2, but the compounds show enhanced selectivity for adsorption of CO2 over N2 at 273 K. The thiol-containing MOFs adsorb mercury(II) ions from aqueous solution, removing up to 99 %. The Mannich reaction with pyrazole succeeds on [Zn4O(bdc-NH2)3] (IRMOF-3), but a similar reaction on [Zn2(bdc-NH2)2(dabco)] (dabco=1,4-diazabicyclo[2.2.2]octane) gave [Zn3(bdc-NH2)1.32(bdc-NHCH2pyz)1.68(dabco)]⋅2 C7H8 5, whereas the reaction with imidazole gave the expected PSM product. Compound 5 forms via a dissolution–recrystallisation process that is triggered by the “free” pyrazolate nitrogen atom competing with dabco for coordination to the zinc(II) centre. In contrast, the “free” nitrogen atom on the imidazolate is too far away to compete in this way. Mannich reactions on [In(OH)(bdc-NH2)] (MIL-68(In)-NH2) stop after the first step, and the product was identified as [In(OH)(bdc-NH2)0.41(bdc-NHCH2OCH3)0.30(bdc-N=CH2)0.29], with addition of the heterocycle prevented by steric interactions.

LanguageEnglish
Pages11094-11102
Number of pages9
JournalChemistry - A European Journal
Volume24
Issue number43
DOIs
StatusPublished - 1 Aug 2018

Fingerprint

Dissolution
Metals
Nitrogen
Atoms
Carbon Monoxide
Mercury
Sulfhydryl Compounds
Zinc
Crystallization
Ions
Adsorption
imidazole
pyrazole
2-mercaptoimidazole
1,4-benzenedicarboxylate
N(1)-methyl-2-lysergic acid diethylamide
triethylenediamine
paraform
zinc 2-amino-1,4-benzenedicarboxylic

Keywords

  • Mannich reactions
  • mercury
  • metal-organic frameworks
  • post-synthetic modification
  • zirconium

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

@article{142a88ee34c04c3fa999bfcba76ce882,
title = "Post-synthetic Mannich chemistry on metal-organic frameworks: system-specific reactivity and functionality-triggered dissolution: System-Specific Reactivity and Functionality-Triggered Dissolution",
abstract = "The Mannich reaction of the zirconium MOF [Zr6O4(OH)4(bdc-NH2)6] (UiO-66-NH2, bdc-NH2=2-amino-1,4-benzenedicarboxylate) with paraformaldehyde and pyrazole, imidazole or 2-mercaptoimidazole led to post-synthetic modification (PSM) through C−N bond formation. The reaction with imidazole (Him) goes to completion whereas those with pyrazole (Hpyz) and 2-mercaptoimidazole (HimSH) give up to 41 and 36 {\%} conversion, respectively. The BET surface areas for the Mannich products are reduced from that of UiO-66-NH2, but the compounds show enhanced selectivity for adsorption of CO2 over N2 at 273 K. The thiol-containing MOFs adsorb mercury(II) ions from aqueous solution, removing up to 99 {\%}. The Mannich reaction with pyrazole succeeds on [Zn4O(bdc-NH2)3] (IRMOF-3), but a similar reaction on [Zn2(bdc-NH2)2(dabco)] (dabco=1,4-diazabicyclo[2.2.2]octane) gave [Zn3(bdc-NH2)1.32(bdc-NHCH2pyz)1.68(dabco)]⋅2 C7H8 5, whereas the reaction with imidazole gave the expected PSM product. Compound 5 forms via a dissolution–recrystallisation process that is triggered by the “free” pyrazolate nitrogen atom competing with dabco for coordination to the zinc(II) centre. In contrast, the “free” nitrogen atom on the imidazolate is too far away to compete in this way. Mannich reactions on [In(OH)(bdc-NH2)] (MIL-68(In)-NH2) stop after the first step, and the product was identified as [In(OH)(bdc-NH2)0.41(bdc-NHCH2OCH3)0.30(bdc-N=CH2)0.29], with addition of the heterocycle prevented by steric interactions.",
keywords = "Mannich reactions, mercury, metal-organic frameworks, post-synthetic modification, zirconium",
author = "{Amer Hamzah}, Harina and William Gee and Paul Raithby and Teat, {Simon J} and Mary Mahon and Andrew Burrows",
year = "2018",
month = "8",
day = "1",
doi = "10.1002/chem.201801419",
language = "English",
volume = "24",
pages = "11094--11102",
journal = "Chemistry - A European Journal",
issn = "0947-6539",
publisher = "Wiley-Blackwell",
number = "43",

}

TY - JOUR

T1 - Post-synthetic Mannich chemistry on metal-organic frameworks: system-specific reactivity and functionality-triggered dissolution

T2 - Chemistry - A European Journal

AU - Amer Hamzah, Harina

AU - Gee, William

AU - Raithby, Paul

AU - Teat, Simon J

AU - Mahon, Mary

AU - Burrows, Andrew

PY - 2018/8/1

Y1 - 2018/8/1

N2 - The Mannich reaction of the zirconium MOF [Zr6O4(OH)4(bdc-NH2)6] (UiO-66-NH2, bdc-NH2=2-amino-1,4-benzenedicarboxylate) with paraformaldehyde and pyrazole, imidazole or 2-mercaptoimidazole led to post-synthetic modification (PSM) through C−N bond formation. The reaction with imidazole (Him) goes to completion whereas those with pyrazole (Hpyz) and 2-mercaptoimidazole (HimSH) give up to 41 and 36 % conversion, respectively. The BET surface areas for the Mannich products are reduced from that of UiO-66-NH2, but the compounds show enhanced selectivity for adsorption of CO2 over N2 at 273 K. The thiol-containing MOFs adsorb mercury(II) ions from aqueous solution, removing up to 99 %. The Mannich reaction with pyrazole succeeds on [Zn4O(bdc-NH2)3] (IRMOF-3), but a similar reaction on [Zn2(bdc-NH2)2(dabco)] (dabco=1,4-diazabicyclo[2.2.2]octane) gave [Zn3(bdc-NH2)1.32(bdc-NHCH2pyz)1.68(dabco)]⋅2 C7H8 5, whereas the reaction with imidazole gave the expected PSM product. Compound 5 forms via a dissolution–recrystallisation process that is triggered by the “free” pyrazolate nitrogen atom competing with dabco for coordination to the zinc(II) centre. In contrast, the “free” nitrogen atom on the imidazolate is too far away to compete in this way. Mannich reactions on [In(OH)(bdc-NH2)] (MIL-68(In)-NH2) stop after the first step, and the product was identified as [In(OH)(bdc-NH2)0.41(bdc-NHCH2OCH3)0.30(bdc-N=CH2)0.29], with addition of the heterocycle prevented by steric interactions.

AB - The Mannich reaction of the zirconium MOF [Zr6O4(OH)4(bdc-NH2)6] (UiO-66-NH2, bdc-NH2=2-amino-1,4-benzenedicarboxylate) with paraformaldehyde and pyrazole, imidazole or 2-mercaptoimidazole led to post-synthetic modification (PSM) through C−N bond formation. The reaction with imidazole (Him) goes to completion whereas those with pyrazole (Hpyz) and 2-mercaptoimidazole (HimSH) give up to 41 and 36 % conversion, respectively. The BET surface areas for the Mannich products are reduced from that of UiO-66-NH2, but the compounds show enhanced selectivity for adsorption of CO2 over N2 at 273 K. The thiol-containing MOFs adsorb mercury(II) ions from aqueous solution, removing up to 99 %. The Mannich reaction with pyrazole succeeds on [Zn4O(bdc-NH2)3] (IRMOF-3), but a similar reaction on [Zn2(bdc-NH2)2(dabco)] (dabco=1,4-diazabicyclo[2.2.2]octane) gave [Zn3(bdc-NH2)1.32(bdc-NHCH2pyz)1.68(dabco)]⋅2 C7H8 5, whereas the reaction with imidazole gave the expected PSM product. Compound 5 forms via a dissolution–recrystallisation process that is triggered by the “free” pyrazolate nitrogen atom competing with dabco for coordination to the zinc(II) centre. In contrast, the “free” nitrogen atom on the imidazolate is too far away to compete in this way. Mannich reactions on [In(OH)(bdc-NH2)] (MIL-68(In)-NH2) stop after the first step, and the product was identified as [In(OH)(bdc-NH2)0.41(bdc-NHCH2OCH3)0.30(bdc-N=CH2)0.29], with addition of the heterocycle prevented by steric interactions.

KW - Mannich reactions

KW - mercury

KW - metal-organic frameworks

KW - post-synthetic modification

KW - zirconium

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U2 - 10.1002/chem.201801419

DO - 10.1002/chem.201801419

M3 - Article

VL - 24

SP - 11094

EP - 11102

JO - Chemistry - A European Journal

JF - Chemistry - A European Journal

SN - 0947-6539

IS - 43

ER -