1
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Giovanardi G, Cattani S, Balestri D, Secchi A, Cera G. Iridium-Catalyzed C-H Borylations: Regioselective Functionalizations of Calix[4]arene Macrocycles. J Org Chem 2024; 89:8486-8499. [PMID: 38816966 DOI: 10.1021/acs.joc.4c00419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
We report iridium-catalyzed C-H borylations for the regioselective synthesis of distally disubstituted calix[4]arene macrocycles. The atom- and step-economical method led to a broad family of calix[4]arenes in good yields and functional group tolerance. The synthetic utility of the C-H borylation protocol was finally illustrated with several late-stage modifications for the synthesis of elaborate calix[4]arenes frameworks, otherwise challenging to achieve with commonly employed procedures.
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Affiliation(s)
- Gabriele Giovanardi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy
| | - Silvia Cattani
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy
| | - Davide Balestri
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy
| | - Andrea Secchi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy
| | - Gianpiero Cera
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy
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2
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Bauder C, Sémeril D. Optically Pure Calixarenyl Phosphine via Stereospecific Alkylation on Evans' Oxazolidinone Moiety. Molecules 2024; 29:1156. [PMID: 38474667 DOI: 10.3390/molecules29051156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 02/26/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024] Open
Abstract
A convenient protocol for the synthesis of 25,26,27-tribenzoyl-28-[((S)-1-diphenylphos- phanyl-propan-2-yl)oxy]-calix[4]arene via stereospecific methylation on Evans' oxazolidinone moiety was reported. According to the 13C NMR analysis of this phosphine, the calix[4]arene skeleton adopted a 1,3-alternate conformation. The latter conformation of the macrocycle and the (S)-chirality of the carbon atom bearing the methyl substituent were confirmed by a single-crystal X-ray diffraction study. After coordination of the phosphinated ligand to the dimeric [RuCl2(p-cymene)]2 organometallic precursor, the resulting arene-ruthenium complex was tested in the asymmetric reduction of acetophenone and alcohol was obtained with modest enantiomeric excess.
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Affiliation(s)
- Claude Bauder
- Synthèse Organométallique et Catalyse, UMR-CNRS 7177 Institut de Chimie de Strasbourg, Strasbourg University, 67008 Strasbourg, France
| | - David Sémeril
- Synthèse Organométallique et Catalyse, UMR-CNRS 7177 Institut de Chimie de Strasbourg, Strasbourg University, 67008 Strasbourg, France
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3
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Banks HJS, Frese JWA, Elsegood MRJ, Redshaw C. Mixed-magnesium/zinc calix[4]arene complexes: structure, and ring opening polymerisation studies. Chem Commun (Camb) 2024; 60:304-307. [PMID: 38059516 DOI: 10.1039/d3cc04899c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
Different combinations of organomagnesium reagents and zinc bromide react with either 1,3-dimethoxy-4-tert-butylcalix[4]areneH2 (L(OMe)2H2) or trialkoxycalix[4]arenes (L(OR)3H) (R = n-Pr, n-pentyl) to afford mixed-metal calix[4]arene systems. Intriguing molecular structures are formed and the systems are capable of the ring opening polymerisation of ε-caprolactone under N2, air, or as melts.
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Affiliation(s)
- Henry J S Banks
- Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Josef W A Frese
- Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Mark R J Elsegood
- Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Carl Redshaw
- Plastics Collaboratory, Chemistry, School of Natural Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
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4
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Mironova D, Bogdanov I, Akhatova A, Sultanova E, Garipova R, Khannanov A, Burilov V, Solovieva S, Antipin I. New Carboxytriazolyl Amphiphilic Derivatives of Calix[4]arenes: Aggregation and Use in CuAAC Catalysis. Int J Mol Sci 2023; 24:16663. [PMID: 38068985 PMCID: PMC10706699 DOI: 10.3390/ijms242316663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
This work focuses on the synthesis of a new series of amphiphilic derivatives of calix[4]arenes for the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The aggregation properties of synthesized calix[4]arenes were studied using various techniques (fluorescence spectroscopy, nanoparticle tracking analysis, and dynamic light scattering). Increasing the length of the alkyl substituent led to stronger hydrophobic interactions, which increased polydispersity in solution. The zwitterionic nature of the synthesized calix[4]arenes was established using different types of dyes (Eosin Y for anionic structures and Rhodamine 6G for cationic structures). The synthesized calix[4]arenes were used as organic stabilizers for CuI. The catalytic efficiency of CuI-calix[4]arene was compared with that of the phase transfer catalyst tetrabutylammonium bromide (TBAB) and the surfactant sodium dodecyl sulfate (SDS). For all calixarenes, the selectivity in the CuAAC reaction was higher than that observed when TBAB and SDS were estimated.
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Affiliation(s)
- Diana Mironova
- Alexander Butlerov Institute of Chemistry, Kazan Federal University, 18 Kremlevskaya Str., 420008 Kazan, Russia
| | - Ilshat Bogdanov
- Alexander Butlerov Institute of Chemistry, Kazan Federal University, 18 Kremlevskaya Str., 420008 Kazan, Russia
| | - Aliya Akhatova
- Alexander Butlerov Institute of Chemistry, Kazan Federal University, 18 Kremlevskaya Str., 420008 Kazan, Russia
| | - Elza Sultanova
- Alexander Butlerov Institute of Chemistry, Kazan Federal University, 18 Kremlevskaya Str., 420008 Kazan, Russia
| | - Ramilya Garipova
- Alexander Butlerov Institute of Chemistry, Kazan Federal University, 18 Kremlevskaya Str., 420008 Kazan, Russia
| | - Artur Khannanov
- Alexander Butlerov Institute of Chemistry, Kazan Federal University, 18 Kremlevskaya Str., 420008 Kazan, Russia
| | - Vladimir Burilov
- Alexander Butlerov Institute of Chemistry, Kazan Federal University, 18 Kremlevskaya Str., 420008 Kazan, Russia
| | - Svetlana Solovieva
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov Str., 420088 Kazan, Russia
| | - Igor Antipin
- Alexander Butlerov Institute of Chemistry, Kazan Federal University, 18 Kremlevskaya Str., 420008 Kazan, Russia
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5
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Giovanardi G, Scarica G, Pirovano V, Secchi A, Cera G. Gold(I)-catalysed hydroarylations of alkynes for the synthesis of inherently chiral calix[4]arenes. Org Biomol Chem 2023; 21:4072-4083. [PMID: 37128860 DOI: 10.1039/d3ob00603d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We describe the first gold(I)-catalysed intramolecular hydroarylation of alkynes for the straightforward synthesis of inherently chiral calix[4]arenes. This step- and atom-economical approach, which exploits a formal meta-functionalisation of the calix[4]arene macrocycle, is able to deliver an ample family of N-heterocyclic, chiral compounds in high yields and functional group tolerance.
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Affiliation(s)
- Gabriele Giovanardi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy.
| | - Gabriele Scarica
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy.
| | - Valentina Pirovano
- Dipartimento di Scienze Farmaceutiche, Sezione di Chimica Generale e Organica "A. Marchesini", Università degli Studi di Milano, Via Venezian, 21, 20133 Milano, Italy
| | - Andrea Secchi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy.
| | - Gianpiero Cera
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy.
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6
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Lee J, Melchakova I, Nayab S, Kim K, Ko YH, Yoon M, Avramov P, Lee H. Synthesis and Characterization of Zinc(II), Cadmium(II), and Palladium(II) Complexes with the Thiophene-Derived Schiff Base Ligand. ACS OMEGA 2023; 8:6016-6029. [PMID: 36816644 PMCID: PMC9933481 DOI: 10.1021/acsomega.2c08001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 01/23/2023] [Indexed: 06/01/2023]
Abstract
Zn(II), Pd(II), and Cd(II) complexes, [L TH MCl 2 ] (M = Zn, Pd; X = Br, Cl) and [L TH Cd(μ-X)X] n (X = Cl, Br; n = n, 2), supported by the (E)-N 1,N 1-dimethyl-N 2-(thiophen-2-ylmethylene)ethane-1,2-diamine (L TH ) ligand are synthesized and structurally characterized. Density functional theory (DFT) electronic structure calculations and variable-temperature NMR support the presence of two conformers and a dynamic interconversion process of the minor conformer to the major one in solution. It is found that the existence of two relevant complex conformers and their respective ratios in solution depend on the central metal ions and counter ions, either Cl- or Br-. Among the two relevant conformers, a single conformer is crystallized and X-ray diffraction analysis revealed a distorted tetrahedral geometry for Zn(II) complexes, and a distorted square planar and square pyramidal geometry for Pd(II) and Cd(II) complexes, respectively. It is shown that [L TH MCl 2 ]/LiO i Pr (M = Zn, Pd) and [L TH Cd(μ-Cl)Cl] n /LiO i Pr can effectively catalyze the ring-opening polymerization (ROP) reaction of rac-lactide (rac-LA) with 94% conversion within 30 s with [L TH ZnCl 2 ]/LiO i Pr at 0 °C. Overall, hetero-enriched poly(lactic acid)s (PLAs) were provided by these catalytic systems with [L TH ZnCl 2 ]/LiO i Pr producing PLA with higher heterotactic bias (P r up to 0.74 at 0 °C).
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Affiliation(s)
- Jaegyeong Lee
- Department
of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea
| | - Iuliia Melchakova
- Department
of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea
| | - Saira Nayab
- Department
of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea
- Department
of Chemistry, Shaheed Benazir Bhutto University
(SBBU), Sheringal 18050, Upper Dir, Khyber Pakhtunkhwa, Islamic Republic of Pakistan
| | - Kyeonghun Kim
- Department
of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea
| | - Young Ho Ko
- Center
for Self-Assembly and Complexity (CSC), Institute for Basic Science
(IBS), Pohang University of Science and
Technology (POSTEC), Pohang 37673, Republic
of Korea
| | - Minyoung Yoon
- Department
of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea
| | - Paul Avramov
- Department
of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea
| | - Hyosun Lee
- Department
of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea
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7
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Oxyethylated Fluoresceine-(thia)calix[4]arene Conjugates: Synthesis and Visible-Light Photoredox Catalysis in Water-Organic Media. MOLECULES (BASEL, SWITZERLAND) 2022; 28:molecules28010261. [PMID: 36615457 PMCID: PMC9821991 DOI: 10.3390/molecules28010261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/21/2022] [Accepted: 12/24/2022] [Indexed: 12/30/2022]
Abstract
Fluorescent derivatives attract the attention of researchers for their use as sensors, photocatalysts and for the creation of functional materials. In order to create amphiphilic fluorescent derivatives of calixarenes, a fluorescein derivative containing oligoethylene glycol and propargyl groups was obtained. The resulting fluorescein derivative was introduced into three different (thia)calix[4]arene azide derivatives. For all synthesized compounds, the luminescence quantum yields have been established in different solvents. Using UV-visible spectroscopy, dynamic light scattering, as well as transmission and confocal microscopy, aggregation of macrocycles was studied. It was evaluated that calixarene derivatives with alkyl substituents form spherical aggregates, while symmetrical tetrafluorescein-containing thiacalix[4]arene forms extended worm-like aggregates. The macrocycle containing tetradecyl fragments was found to be the most efficient in photoredox ipso-oxidation of phenylboronic acid. In addition, it was shown that in a number of different electron donors (NEt3, DABCO and iPr2EtN), the photoredox ipso-oxidation proceeds best with triethylamine. It has been shown that a low molecular weight surfactant Triton-X100 can also improve the photocatalytic abilities of an oligoethylene glycol fluorescein derivative, thus showing the importance of a combination of micellar and photoredox catalysis.
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8
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Turley AT, Hanson-Heine MWD, Argent SP, Hu Y, Jones TA, Fay M, Woodward S. Catalysis enabled synthesis, structures, and reactivities of fluorinated S 8-corona[ n]arenes ( n = 8-12). Chem Sci 2022; 14:70-77. [PMID: 36605745 PMCID: PMC9769089 DOI: 10.1039/d2sc05348a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 11/13/2022] [Indexed: 11/18/2022] Open
Abstract
Previously inaccessible large S8-corona[n]arene macrocycles (n = 8-12) with alternating aryl and 1,4-C6F4 subunits are easily prepared on up to gram scales, without the need for chromatography (up to 45% yield, 10 different examples) through new high acceleration SNAr substitution protocols (catalytic NR4F in pyridine, R = H, Me, Bu). Macrocycle size and functionality are tunable by precursor and catalyst selection. Equivalent simple NR4F catalysis allows facile late-stage SNAr difunctionalisation of the ring C6F4 units with thiols (8 derivatives, typically 95+% yields) providing two-step access to highly functionalised fluoromacrocycle libraries. Macrocycle host binding supports fluoroaryl catalytic activation through contact ion pair binding of NR4F and solvent inclusion. In the solid-state, solvent inclusion also intimately controls macrocycle conformation and fluorine-fluorine interactions leading to spontaneous self-assembly into infinite columns with honeycomb-like lattices.
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Affiliation(s)
- Andrew. T. Turley
- GSK Carbon Neutral Laboratories for Sustainable Chemistry, University of Nottingham, Jubilee CampusNottingham NG7 2TUUK
| | | | - Stephen. P. Argent
- School of Chemistry, University of Nottingham, University Park CampusNottingham NG7 2RDUK
| | - Yaoyang Hu
- GSK Carbon Neutral Laboratories for Sustainable Chemistry, University of Nottingham, Jubilee CampusNottingham NG7 2TUUK
| | - Thomas. A. Jones
- GSK Carbon Neutral Laboratories for Sustainable Chemistry, University of Nottingham, Jubilee CampusNottingham NG7 2TUUK
| | - Michael Fay
- Nanoscale and Microscale Research Centre, University of Nottingham, University Park CampusCripps South BuildingNottinghamNG7 2RDUK
| | - Simon Woodward
- GSK Carbon Neutral Laboratories for Sustainable Chemistry, University of Nottingham, Jubilee CampusNottingham NG7 2TUUK
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9
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Calix[4]arene Polyamine Triazoles: Synthesis, Aggregation and DNA Binding. Int J Mol Sci 2022; 23:ijms232314889. [PMID: 36499212 PMCID: PMC9738031 DOI: 10.3390/ijms232314889] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/20/2022] [Accepted: 11/24/2022] [Indexed: 11/29/2022] Open
Abstract
Artificial gene delivery systems are in great demand from both scientific and practical biomedical points of view. In this paper, we present the synthesis of a new click chemistry calix[4]arene precursor with free lower rim and new water-soluble calixarene triazoles with 12 amino-groups on the upper rim (one with free phenol hydroxyl groups and two another containing four butyl or tetradecyl fragments). Aggregation in the series of amino-triazole calixarenes of different lipophilicity (calixarene with free phenol hydroxyl groups or butyl and tetradecyl fragments on the lower rim) was studied using dynamic light scattering and fluorescent pyrene probe. It was found that calix[4]arene with a free lower rim, like alkyl-substituted butyl calix[4]arene, forms stable submicron aggregates 150-200 nm in size, while the more lipophilic tetradecyl -substituted calix[4]arene forms micellar aggregates19 nm in size. Using UV-Vis spectroscopy, fluorimetry and CD, it was shown that amino-triazole calix[4]arenes bind to calf thymus DNA by classical intercalation. According to DLS and TEM data, all studied macrocycles cause significant DNA compaction, forming stable nanoparticles 50-20 nm in size. Among all studied calix[4]arenes the most lipophilic tetradecyl one proved to be the best for both binding and compaction of DNA.
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10
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How Do Positions of Phosphito Units on a Calix[4]Arene Platform Affect the Enantioselectivity of a Catalytic Reaction? ORGANICS 2022. [DOI: 10.3390/org3040030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Three chiral diphosphites, (S,S)-5,17-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy)-25,26,27,28-tetrapropyloxycalix[4]arene (1), (S,S)-5,11,17,23-tetra-tert-butyl-25,27-dipropoxy-26,28-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy)calix[4]arene (2) and (S,S)-5,11,17,23-tetra-tert-butyl-25,26-dipropoxy-27,28-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy)calix[4]arene (3), based on conical calix[4]arene were investigated in the rhodium-catalyzed asymmetric hydrogenation of α-dehydroamino esters. High conversions were observed after 24 h under 5 bar of hydrogen whatever the employed diphosphite, and the chiral induction increases in the order 1 < 3 < 2. This may be due to the presence of the calix[4]arene moiety, which by its presence modifies the second coordination sphere of the catalytic center. The larger steric hindrance around the rhodium atom leads to the higher enantiomeric excess.
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11
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Talmazan RA, Refugio Monroy J, del Río‐Portilla F, Castillo I, Podewitz M. Encapsulation Enhances the Catalytic Activity of C-N Coupling: Reaction Mechanism of a Cu(I)/Calix[8]arene Supramolecular Catalyst. ChemCatChem 2022; 14:e202200662. [PMID: 36605358 PMCID: PMC9804476 DOI: 10.1002/cctc.202200662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/11/2022] [Indexed: 01/07/2023]
Abstract
Development of C-N coupling methodologies based on Earth-abundant metals is a promising strategy in homogeneous catalysis for sustainable processes. However, such systems suffer from deactivation and low catalytic activity. We here report that encapsulation of Cu(I) within the phenanthroyl-containing calix[8]arene derivative 1,5-(2,9-dimethyl-1,10-phenanthroyl)-2,3,4,6,7,8-hexamethyl-p-tert-butylcalix[8]arene (C8PhenMe6 ) significantly enhances C-N coupling activity up to 92 % yield in the reaction of aryl halides and aryl amines, with low catalyst loadings (2.5 % mol). A tailored multiscale computational protocol based on Molecular Dynamics simulations and DFT investigations revealed an oxidative addition/reductive elimination process of the supramolecular catalyst [Cu(C8PhenMe6)I]. The computational investigations uncovered the origins of the enhanced catalytic activity over its molecular analogues: Catalyst deactivation through dimerization is prevented, and product release facilitated. Capturing the dynamic profile of the macrocycle and the impact of non-covalent interactions on reactivity allows for the rationalization of the behavior of the flexible supramolecular catalysts employed.
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Affiliation(s)
- Radu A. Talmazan
- Institute of Materials ChemistryTU WienGetreidemarkt 91060ViennaAustria
- Institute of General, Inorganic, and Theoretical Chemistry and Center of Molecular BiosciencesUniversity of InnsbruckInnrain 80/826020InnsbruckAustria
| | - J. Refugio Monroy
- Instituto de QuímicaUniversidad Nacional Autónoma de MéxicoCircuito ExteriorCU, Ciudad de México04510México
- Present address: Department of ChemistryHumboldt Universität zu BerlinBrook-Taylor-Strasse 212489BerlinGermany
| | - Federico del Río‐Portilla
- Instituto de QuímicaUniversidad Nacional Autónoma de MéxicoCircuito ExteriorCU, Ciudad de México04510México
| | - Ivan Castillo
- Instituto de QuímicaUniversidad Nacional Autónoma de MéxicoCircuito ExteriorCU, Ciudad de México04510México
| | - Maren Podewitz
- Institute of Materials ChemistryTU WienGetreidemarkt 91060ViennaAustria
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12
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Bonati FC, Secchi A, Cera G. Recent advances with calix[6]- and calix[8]arene organometallic catalysts. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.154221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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13
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A Calix[8]arene-Based Catalyst for Suzuki–Miyaura Couplings with Reduced Pd_Leaching. Catalysts 2022. [DOI: 10.3390/catal12101098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Pd-catalysed reactions are amongst the most important in current chemistry. Consequently, very reactive catalysts were developed during the last decades, allowing very high conversions at low catalytic rates. However, decreasing Pd leaching in final products without decreasing catalyst efficiency remains an unsolved issue, especially in the pharma industry. We recently showed that using calixarenes as platforms for Pd-based catalysts constitutes an efficient answer to this concern. In the present work, we show that using these calixarenic platforms in combination with suitably engineered ligands allows for an even more strongly decreased Pd leaching. It thus opens up interesting perspectives for the synthesis of new families of catalysts combining a very high reactivity and a very low Pd leaching in final products.
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14
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Shan PH, Hu JH, Liu M, Tao Z, Xiao X, Redshaw C. Progress in host–guest macrocycle/pesticide research: Recognition, detection, release and application. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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15
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Rawat V, Vigalok A, Sinha AK, Sachdeva G, Srivastava CM, Rao GK, Kumar A, Singh M, Rathi K, Verma VP, Yadav B, Pandey AK, Vats M. Synthesis of a Zirconium Complex of an N, O-type p- tert-Butylcalix[4]arene and Its Application in Some Multicomponent Reactions. ACS OMEGA 2022; 7:28471-28480. [PMID: 35990458 PMCID: PMC9386809 DOI: 10.1021/acsomega.2c03187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
The synthesis and characterization of a new octahedral Zr(IV) complex of oxygen-depleted N,O-type calixarene ligand comprising two distal-functionalized pyrazole rings have been reported. The cone shape and structure of the prepared complex were confirmed univocally by single-crystal X-ray diffraction and NMR studies. The Zr metal lies at 2.091 Å from the plane of the calixarene ring. This complex has been utilized as an efficient catalyst for the synthesis of Biginelli adducts, bis(indolyl)methanes, and coumarins. This complex (Cl2Zr-calixarene) showed superior activity for these multicomponent reactions in comparison to the corresponding Ti(IV) and Zn(II) analogues. Ferrocene-appended bis(indolyl)methane, prepared using this catalyst, was also evaluated for its anticancer activity against the A-172 cell line.
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Affiliation(s)
- Varun Rawat
- Amity
School of Applied Sciences, Amity University
Haryana, Gurugram 122413, India
- School
of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Arkadi Vigalok
- School
of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Anshu Kumar Sinha
- Amity
School of Applied Sciences, Amity University
Haryana, Gurugram 122413, India
| | - Garima Sachdeva
- Amity
School of Applied Sciences, Amity University
Haryana, Gurugram 122413, India
| | | | - Gyandshwar K. Rao
- Amity
School of Applied Sciences, Amity University
Haryana, Gurugram 122413, India
| | - Arun Kumar
- Department
of Chemistry, School of Physical Sciences, Doon University, Dehradun 248012, Uttarakhand, India
| | - Mandeep Singh
- Nuchem
Sciences, Saint-Laurent, Quebec H4R2N6, Canada
| | - Komal Rathi
- Department
of Chemistry, Banasthali University, Banasthali Newai 304002, Rajasthan, India
| | - Ved Prakash Verma
- Department
of Chemistry, Banasthali University, Banasthali Newai 304002, Rajasthan, India
| | - Bhupender Yadav
- Amity Institute
of Biotechnology, Amity University Haryana, Gurugram 122413, India
| | - Amit Kumar Pandey
- Amity Institute
of Biotechnology, Amity University Haryana, Gurugram 122413, India
| | - Monika Vats
- Amity
School of Applied Sciences, Amity University
Haryana, Gurugram 122413, India
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16
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Tian YQ, Cui YS, Zhu JH, Xu CQ, Yi XY, Li J, Liu C. Ancillary ligand-regulated Ti(IV)-based metallocalixarene coordination cages for photocatalytic H 2 evolution. Chem Commun (Camb) 2022; 58:9034-9037. [PMID: 35876039 DOI: 10.1039/d2cc03131k] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High-valence Ti(IV)-based metallocalixarene coordination cages that are linked by oriented ancillary ligands are unknown so far. Herein, the first family of tunable calixarene-based coordination cages of Ti(IV) with a framework formula [Ti12(OiPr)12(TBC[4])6L6] have been assembled from six {Ti2(OiPr)2(TBC[4])}2+ nodes and six pyridinedicarboxylic ligands. Furthermore, the {Ti12L6} cage showed strong photocatalytic H2 evolution activity, and DFT studies were performed to explore its electronic structure.
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Affiliation(s)
- Yi-Qi Tian
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
| | - Yun-Shu Cui
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Jia-Hui Zhu
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
| | - Cong-Qiao Xu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Xiao-Yi Yi
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
| | - Jun Li
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China. .,Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Tsinghua University, 100084 Beijing, China
| | - Chao Liu
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
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17
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Xing T, Frese JWA, Derbyshire M, Glenister MA, Elsegood MRJ, Redshaw C. Trinuclear zinc calix[4]arenes: synthesis, structure, and ring opening polymerization studies. Dalton Trans 2022; 51:11776-11786. [PMID: 35860977 DOI: 10.1039/d2dt01496c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The trinuclear zinc calix[4]arene complexes [Zn3(O2CCH3)2(L(O)2(OMe)2)2·xMeCN (x = 7.5, 1; x = 6, 1'), [Zn3(O2CCH3)2(L(O)2(OnPr)2)2·5MeCN (2·5MeCN), [Zn3(OEt)2(L(O)2(OMe)2)2]·4MeCN (3·4MeCN), [Zn3(OEt)2(L(Opentyl)2)2]·4.5MeCN (4·4.5MeCN) and [Zn3(OH)2(L(O)2(On-pentyl)2]·8MeCN (5·8MeCN) have been isolated from reaction of [(ZnEt)2(L(O)2(OR)2)2] (L(OH)2(OR)2 = 1,3-dialkoxy-4-tert-butylcalix[4]arene; R = methyl, n-propyl or pentyl) and the reagents acetic acid, ethanol, and presumed adventitious water, respectively. Attempts to make 5via a controlled hydrolysis led only to the isolation of polymorphs of (L(OH)2(Opentyl)2·MeCN. Reaction of [Zn(C6F5)2] with L(OH)2(Opentyl)2, in the presence of K2CO3, led to the isolation of the complex [Zn6(L(On-pentyl))2(OH)3(C6F5)3(NCMe)3]·3MeCN (6·3MeCN). The molecular structures of 1-6 reveal they all contain a near linear (163 to 179°) Zn3 motif. In 1-5, a central tetrahedral Zn centre is flanked by trigonal bipyramidal Zn centres, whilst in 6, for the linear Zn3 unit, a central distorted octahedral zinc centre is flanked by trigonal planar and a tetrahedral zinc centres. Screening for the ring opening polymerization (ROP) of ε-caprolactone at 90 °C revealed that they are active with moderate to good conversion affording low to medium molecular weight products with at least two series of ions. For comparative studies, the trinuclear aminebis(phenolate) complex [Zn3(Oi-Pr)2L/] (L/ = n-propylamine-N,N-bis(2-methylene-4,6-di-tert-butylphenolate) I was prepared. Kinetics revealed the rate order I > 4 > 6 ≈ 2 ≈ 1 > 3.
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Affiliation(s)
- Tian Xing
- Plastics Collaboratory, Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
| | - Josef W A Frese
- Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Max Derbyshire
- Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Mollie A Glenister
- Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Mark R J Elsegood
- Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Carl Redshaw
- Plastics Collaboratory, Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
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18
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Xing T, Derbyshire M, Elsegood MRJ, Redshaw C. Mixed-metal calix[8]arene complexes: structure, and ring opening polymerisation studies. Chem Commun (Camb) 2022; 58:7427-7430. [PMID: 35696201 DOI: 10.1039/d2cc02236b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactions of différent combinations of group V alkoxides or tungsten oxyalkoxide salts with p-tert-butylcalix[8]areneH8 (L8H8) affords mixed-metal calix[8]arene systems. Intruiging molecular structures are formed and the systems are capable of the ring opening polymerisation of ε-caprolactone under N2, air, or as melts affording mostly low molecular weight products.
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Affiliation(s)
- Tian Xing
- Plastics Collaboratory, Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
| | - Max Derbyshire
- Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Mark R J Elsegood
- Chemistry Department, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Carl Redshaw
- Plastics Collaboratory, Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
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19
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Tian YQ, Cui YS, Yu WD, Xu CQ, Yi XY, Yan J, Li J, Liu C. An ultrastable Ti-based metallocalixarene nanocage cluster with photocatalytic amine oxidation activity. Chem Commun (Camb) 2022; 58:6028-6031. [PMID: 35502757 DOI: 10.1039/d2cc01740g] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Polyhedral metallocalixarene nanocage clusters based on pure Ti(IV) ions are to our knowledge unknown hitherto. Herein we report the first Ti(IV)-based metallocalixarene nanocage cluster by assembling a [Ti13O14] cage with six t-butylcalix[4]arene molecules. Notably, the cluster exhibits extraordinary stability in high-concentration acid/alkali solutions and can act as a stable photocatalyst to catalyze the oxidation of ammonia to imines.
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Affiliation(s)
- Yi-Qi Tian
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
| | - Yun-Shu Cui
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China.
| | - Wei-Dong Yu
- College of Science, Hunan University of Technology and Business, Changsha 410000, P. R. China
| | - Cong-Qiao Xu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China.
| | - Xiao-Yi Yi
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
| | - Jun Yan
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
| | - Jun Li
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China.
| | - Chao Liu
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, P. R. China.
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20
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Ignaszak A, Patterson N, O'Brien C, True A, Elsegood MRJ, Prior TJ, Redshaw C. Heterometallic cobalt(ii) calix[6 and 8]arenes: synthesis, structure and electrochemical activity. RSC Adv 2022; 12:11672-11685. [PMID: 35481098 PMCID: PMC9010074 DOI: 10.1039/d2ra01009g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/14/2022] [Indexed: 11/21/2022] Open
Abstract
Heterometallic cobalt p-tert-butylcalix[6 and 8]arenes have been generated from the in situ reaction of lithium reagents (n-BuLi or t-BuOLi) or NaH with the parent calix[n]arene and subsequent reaction with CoBr2. The reverse route, involving the addition of in situ generated Li[Co(Ot-Bu)3] to p-tert-butylcalix[6 and 8]arene, has also been investigated. X-ray crystallography reveals the formation of complicated products incorporating differing numbers of cobalt and lithium or sodium centers, often with positional disorder, as well as, in some cases, the retention of halide. The electrochemical analysis revealed several oxidation events related to the subsequent oxidation of Co(ii) centers and the reduction of the metal cation at negative potentials. Moreover, the electrochemical activity of the phenol moieties of the parent calix[n]arenes resulted in dimerized products or quinone derivatives, leading to insoluble oligomeric products that deposit and passivate the electrode. Preliminary screening for electrochemical proton reduction revealed good activity for a number of these systems. Results suggest that [Co6Na(NCMe)6(μ-O)(p-tert-butylcalix[6]areneH)2Br]·7MeCN (6·7MeCN) is a promising molecular catalyst for electrochemical proton reduction, with a mass transport coefficient, catalytic charge transfer resistance and current magnitude at the catalytic turnover region that are comparable to those of the reference electrocatalyst (Co(ii)Cl2). Reactions between p-tert-butylcalix[6 and 8]arenes and lithium or sodium reagents led to complex structures often with positional disorder. Such systems are capable of electrochemical proton reduction.![]()
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Affiliation(s)
- Anna Ignaszak
- Department of Chemistry, University of New Brunswick 30 Dineen Drive Fredericton NB E3B 5A3 Canada
| | - Nigel Patterson
- Department of Chemistry, University of New Brunswick 30 Dineen Drive Fredericton NB E3B 5A3 Canada
| | - Connor O'Brien
- Department of Chemistry, University of New Brunswick 30 Dineen Drive Fredericton NB E3B 5A3 Canada
| | - Allison True
- Department of Chemistry, University of New Brunswick 30 Dineen Drive Fredericton NB E3B 5A3 Canada
| | - Mark R J Elsegood
- Chemistry Department, Loughborough University Loughborough Leicestershire LE11 3TU UK
| | - Timothy J Prior
- Department of Chemistry, University of Hull Cottingham Road Hull HU6 7RX UK
| | - Carl Redshaw
- Department of Chemistry, University of Hull Cottingham Road Hull HU6 7RX UK
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21
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Schulz E, Abi Fayssal S, Naret T, Buendia J, Labattut A, Huc V, Martini C. Synthesis, catalytic activity and comparative leaching studies of calix[8]arene‐supported Pd‐NHC complexes for Suzuki‐Miyaura cross‐couplings. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202101204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Timothée Naret
- Universite Paris-Saclay Faculte des Sciences d'Orsay FRANCE
| | | | - Axel Labattut
- Universite Paris-Saclay Faculte des Sciences d'Orsay FRANCE
| | - Vincent Huc
- Universite Paris-Saclay Faculte des Sciences d'Orsay FRANCE
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22
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Xing T, Prior TJ, Redshaw C. Lead calix[ n]arenes ( n = 4, 6, 8): structures and ring opening homo-/co-polymerization capability for cyclic esters. Dalton Trans 2021; 50:15140-15152. [PMID: 34612241 DOI: 10.1039/d1dt02790e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of [LiPb(OiPr)3]2 (generated in situ) with either p-tert-butylcalix[4]areneH4 (L4H4) or p-tert-butylcalix[6]areneH6 (L6H6) resulted in the heterometallic lithium/lead complexes [Pb4Li2(L4)4H6(MeCN)3]·4.5MeCN (1·4.5MeCN) and [Pb8Li10Cl2(L6H2)3(L6)(OH)2(O)2(H2O)2(MeCN)4]·14MeCN (2·14MeCN), respectively. Use of the dimethyleneoxa-bridged p-tert-butyltetrahomodioxacalix[6]areneH6 (L6'H6) with five equivalents of [Pb(OiPr)2] afforded [Pb13(L6')3O4(iPrOH)]·11MeCN (3·11MeCN). Use of the larger p-tert-butylcalix[8]areneH8 (L8H8) with [Pb(OtBu)2] or {Pb[N(TMS)2]} (TMS = SiMe3) afforded the products [Pb12(L8)2O4]·8.7C7H8 (4·8.7C7H8) or [Pb6(SiMe3)2(L8)O2Cl2] (5), respectively. Reaction of {Pb[N(TMS)2]} (generated in situ from (Me3Si)2NH, nBuLi and PbCl2) with L6H6 afforded, after work-up (MeCN), the mixed-metal complex [Pb10Li2(L6)2(OH)Cl(O)4]·9.5MeCN (6·9.5MeCN). Reaction of distilled {Pb[N(TMS)2]} (six equivalents) with L8H8 resulted in the complex [Pb12(L8)2O4]·12MeCN (7·12MeCN). Complexes 1-7, Pb(OiPr)2 and [Pb(N(TMS)2)2] have been screened for their potential to act as pre-catalysts in the ring opening polymerization (ROP) of ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL) and the copolymerization thereof. Generally, the lithiated complexes 1 and 2 exhibited better activities than the other pre-catalysts screened herein. For ε-CL and δ-VL, moderate activity at 130 °C over 24 h was observed for 1-7. In the case of the co-polymerization of ε-CL with δ-VL, 1-7, Pb(OiPr)2 and [Pb(N(TMS)2)2] afforded reasonable conversions and high molecular weight polymers. The systems 1-7, Pb(OiPr)2 and [Pb(N(TMS)2)2] also proved to be active in the ROP of the rac-lactide (r-LA); the activity trend was found to be 1 > 2 ≈ Pb(OiPr)2 ≈ [Pb(N(TMS)2)2] > 4 > 5 ≈ 6 ≈ 7 > 3.
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Affiliation(s)
- Tian Xing
- Plastics Collaboratory, Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
| | - Timothy J Prior
- Plastics Collaboratory, Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
| | - Carl Redshaw
- Plastics Collaboratory, Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
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23
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Xing T, Jiang C, Elsegood MRJ, Redshaw C. Lithiated Calix[ n]arenes ( n = 6 or 8): Synthesis, Structures, and Use in the Ring-Opening Polymerization of Cyclic Esters. Inorg Chem 2021; 60:15543-15556. [PMID: 34596403 DOI: 10.1021/acs.inorgchem.1c02192] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A variety of lithiated calix[n]arenes, for which n = 6 or 8, have been isolated, structurally characterized, and evaluated as catalysts for the ring-opening polymerization (ROP) of the cyclic esters ε-caprolactone (ε-CL), δ-valerolactone (δ-VL), and rac-lactide (r-LA). In particular, interaction of p-tert-butylcalix[6]areneH6 (L6H6) with LiOtBu in THF led to the isolation of [Li14(L6H)2(CO3)2(THF)6(OH2)6]·14THF (1·14THF), the core of which has a chain of five Li2O2 diamonds. Similar use of p-tert-butylcalix[8]areneH8 (L8H8) afforded [Li10(L8)(OH)2(THF)8]·7THF (2·7THF), where the core is composed of a six-rung Li-O ladder. Use of debutylated calix[8]areneH8 (deBuL8H8) led to an elongated dimer [Li18(deBuL8)2(OtBu)2(THF)14]·4THF (3·4THF) in which the calix[8]arenes possess a wavelike conformation forming bridges to link three separate LixOy clusters (where x and y = 6, ignoring the THF donor oxygens). Interaction of L8H8 with LiOH·H2O afforded [Li4(L8H4)(OH2)4(THF)6]·5.5THF (4·5.5THF), where intramolecular H-bond interactions involving Li, O, and H construct a cage in the core of the structure with six- and eight-membered rings. Lastly, addition of Me3Al to the solution generated from L8H8 and LiOtBu led to the isolation of [(AlMe2)2Li20(L8H2)2(OH2)4(O2-)4(OH)2(NCMe)12]·10MeCN (5·10MeCN) in which Li, O, Al, and N centers build a polyhedral core. These complexes have been screened for their potential to act as precatalysts in the ring-opening polymerization (ROP) of ε-CL, δ-VL, and r-LA. For the ROP of ε-CL, δ-VL, and r-LA, systems 1-4 exhibited moderate activity at 130 °C over 8 h. In the case of ROP using the mixed-metal (Li/Al) system 5, better conversions and high molecular weight polymers were achieved. In the case of the ROP of ω-pentadecalactone (ω-PDL), the systems proved to be inactive under the conditions employed herein.
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Affiliation(s)
- Tian Xing
- Plastics Collaboratory, Department of Chemistry, University of Hull, Hull HU6 7RX, U.K
| | - Chengying Jiang
- Chemistry Department, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K
| | - Mark R J Elsegood
- Chemistry Department, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K
| | - Carl Redshaw
- Plastics Collaboratory, Department of Chemistry, University of Hull, Hull HU6 7RX, U.K
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