1
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Santulli F, Tufano F, Cozzolino M, D'Auria I, Strianese M, Mazzeo M, Lamberti M. Cooperative effects of Schiff base binuclear zinc complexes on the synthesis of aliphatic and semi-aromatic polyesters. Dalton Trans 2023; 52:14400-14408. [PMID: 37791380 DOI: 10.1039/d3dt02396f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
In this paper, we use mono- and bimetallic complexes based on Earth-abundant, cheap and benign zinc for the synthesis of sustainable aliphatic and semi-aromatic polyesters. Tridentate and hexadentate aldimine-thioetherphenolate ligands were used to obtain the desired zinc complexes by the reaction of proligands with opportune equivalents of zinc bis[bis(trimethylsilyl)amide]. The obtained bimetallic complexes 1 and 2 and the monometallic complex 3 were used as catalysts in the Ring-Opening Polymerization (ROP) of landmark cyclic esters, such as ε-caprolactone and lactide, and in the Ring-Opening COPolymerization (ROCOP) of cyclohexene oxide and phthalic anhydride under different reaction conditions. All catalysts were active in these two classes of reactions, showing good control of the polymerization processes. Interestingly, the bimetallic complexes have higher activity compared to their monometallic counterparts, highlighting the cooperation between the two zinc centers.
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Affiliation(s)
- Federica Santulli
- Department of Chemistry and Biology "Adolfo Zambelli" University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
| | - Federica Tufano
- Department of Chemistry and Biology "Adolfo Zambelli" University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
| | - Mariachiara Cozzolino
- Department of Chemistry and Biology "Adolfo Zambelli" University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
| | - Ilaria D'Auria
- Department of Chemistry and Biology "Adolfo Zambelli" University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
| | - Maria Strianese
- Department of Chemistry and Biology "Adolfo Zambelli" University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
| | - Mina Mazzeo
- Department of Chemistry and Biology "Adolfo Zambelli" University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
| | - Marina Lamberti
- Department of Chemistry and Biology "Adolfo Zambelli" University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
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2
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Tansky M, Comito RJ. Bimetallic polymerization of lactide with binaphthol-derived bis-heteroscorpionate dizinc and dimagnesium complexes. Dalton Trans 2023. [PMID: 37318380 DOI: 10.1039/d3dt00592e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Discrete bimetallic catalysts often provide enhanced reactivity and selectivity in lactone polymerization, making metal-metal cooperativity an important design principle for new catalyst development. However, the poor modularity of binucleating ligands limits structure-reactivity analysis and optimization. This report describes a modular, binucleating bis(pyrazolyl)alkane ligand series (1-R) bridged by a chiral binaphthol unit, prepared by nucleophile-catalyzed condensation between a dialdehyde and a bis(pyrazolyl)methanone. A bis(ethylzinc) complex was characterized by single-crystal X-ray diffraction, but in situ complexation with Zn(HMDS)2 and Mg(HMDS)2 provided more active catalysts for lactide polymerization (HMDS- = hexamethyldisilazide). Structure-reactivity studies identified complexes of 1-Me2 as the most active, and these catalysts show significant enhancements in rate compared to their monometallic analogues. Kinetic analysis resulted in first-order dependence on both mono- and bimetallic catalysts, suggesting metal-metal cooperativity as the basis for this rate enhancement. End-group analysis and low dispersity implicate a coordination-insertion mechanism through an alkoxide. Despite rapid transesterification observed by MALDI, we still demonstrated controlled polymerization in the block copolymerization of ε-caprolactone and L-lactide. Although we observed rate differences in the polymerization of L-lactide by opposite enantiomer catalysts, we did not observe catalyst-directed stereoselectivity in the polymerization of rac- or meso-lactide.
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Affiliation(s)
- Maxym Tansky
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA.
| | - Robert J Comito
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA.
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3
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Gu Z, Comito RJ. Binucleating Bis(pyrazolyl)alkane Ligands and Their Cationic Dizinc Complexes: Modular, Bimetallic Catalysts for Ring-Opening Polymerization. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zipeng Gu
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Robert J. Comito
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
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4
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Qian J, Comito RJ. Site-Isolated Main-Group Tris(2-pyridyl)borate Complexes by Pyridine Substitution and Their Ring-Opening Polymerization Catalysis. Inorg Chem 2022; 61:10852-10862. [PMID: 35776081 DOI: 10.1021/acs.inorgchem.2c01289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tris(2-pyridyl)borates are an emerging class of scorpionate ligands, distinguished as exceptionally robust and electron-donating. However, the rapid formation of inert homoleptic complexes with divalent metals has so far limited their catalytic utility. We report site-isolating tris(2-pyridyl)borate ligands, bearing isopropyl, tert-butyl, and mesityl substituents at the pyridine 6-position to suppress the formation of inert homoleptic complexes. These ligands form the first 1:1 complexes between tris(2-pyridyl)borates and Mg2+, Zn2+, or Ca2+, with isopropyl-substituted TpyiPrH showing the most generality. Single-crystal X-ray diffraction analysis of the resulting complexes and comparison to density functional theory (DFT) models showed geometric distortions driven by steric repulsion between the pyridine 6-substituents and the hexamethyldisilazide (HMDS-, -N(SiMe3)2) anion. We show that this steric profile is a feature of the six-membered pyridine ring and contrasts with more established tris(pyrazolyl)borate and tris(imidazoline)borate scorpionate complexes. TpyiPrMg(HMDS) (1) and its zinc analogue are moderately active for the controlled polymerization of l-lactide, ε-caprolactone, and trimethylene carbonate. Furthermore, 1 gives controlled polymerization under more demanding melt-phase polymerization conditions at 100 °C, and block copolymerization of ε-caprolactone and trimethylene carbonate. These results will enable useful catalysis and coordination chemistry studies with tris(2-pyridyl)borates, and characterizes their structural complementarity to more familiar scorpionate ligands.
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Affiliation(s)
- Jin Qian
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Robert J Comito
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
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5
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Liao X, Cui FC, He JH, Ren WM, Lu XB, Zhang YT. Sustainable Approach for Synthesis and Completely Recycle of Cyclic CO 2-based Polycarbonates. Chem Sci 2022; 13:6283-6290. [PMID: 35733884 PMCID: PMC9159078 DOI: 10.1039/d2sc01387h] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/21/2022] [Indexed: 11/23/2022] Open
Abstract
It is highly desirable to reduce the environmental pollution related to the disposal of end-of-life plastics. Polycarbonates derived from the copolymerization of CO2 and epoxides have attracted much attention since they can enable CO2-fixation and furnish biorenewable and degradable polymeric materials. So far, only linear CO2-based polycarbonates have been reported and typically degraded to cyclic carbonates. Here we synthesize a homogeneous dinuclear methyl zinc catalyst ((BDI-ZnMe)2, 1) to rapidly copolymerize meso-CHO and CO2 into poly(cyclohexene carbonate) (PCHC) with an unprecedentedly cyclic structure. Moreover, in the presence of trace amounts of water, a heterogeneous multi-nuclear zinc catalyst ((BDI-(ZnMe2·xH2O))n, 2) is prepared and shows up to 99% selectivity towards the degradation of PCHC back to meso-CHO and CO2. This strategy not only achieves the first case of cyclic CO2-based polycarbonate but also realizes the complete chemical recycling of PCHC back to its monomers, representing closed-loop recycling of CO2-based polycarbonates. It is highly desirable to reduce the environmental pollution related to the disposal of end-of-life plastics.![]()
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Affiliation(s)
- Xi Liao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University 130012 Changchun P. R. China
| | - Feng-Chao Cui
- Faculty of Chemistry, Northeast Normal University 130024 Changchun P. R. China
| | - Jiang-Hua He
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University 130012 Changchun P. R. China
| | - Wei-Min Ren
- State Key Laboratory of Fine Chemicals, Dalian University of Technology 116024 Dalian P. R. China
| | - Xiao-Bing Lu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology 116024 Dalian P. R. China
| | - Yue-Tao Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University 130012 Changchun P. R. China
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6
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Synthesis of Biodegradable Polymers: A Review on the Use of Schiff-Base Metal Complexes as Catalysts for the Ring Opening Polymerization (ROP) of Cyclic Esters. Catalysts 2020. [DOI: 10.3390/catal10070800] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
This review describes the recent advances (from 2008 onwards) in the use of Schiff-base metal complexes as catalysts for the ring opening polymerization (ROP) of cyclic esters. The synthesis and structure of the metal complexes, as well as all aspects concerning the polymerization process and the characteristics of the polymers formed, will be discussed.
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7
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Zhao PC, Chang FF, Feng FD, Huang W. Transmetalation and Demetallization for Open-Oyster-like Non-Ionic Cd(II) Macrocycles. Inorg Chem 2020; 59:7504-7511. [PMID: 32436384 DOI: 10.1021/acs.inorgchem.0c00304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work designed a nonionic extended dialdehyde 6,6'-(phenylazanediyl)dipicolinaldehyde (PDPA) for constructing Schiff-base macrocyclic complexes with weaker metal-ligand interactions, so as to solve the long-standing challenges of transmetalation and demetallization in macrocyclic complexes. An enantiomeric pair of open-oyster-like 26-membered [2 + 2] Schiff-base macrocyclic dinuclear Cd(II) complexes (S,S-1a, R,R-1b) could be obtained, having S,S/R,R-1,2-diaminocyclohexane (S,S/R,R-DACH) precursors, while Cu(II) ion template only resulted in a mononuclear Schiff-base Cu(II) acyclic complex (S,S-2) accompanied by the half-oxidation of PDPA instead of expected [2 + 2] Cu(II) macrocyclic complexes. It is suggested that the weak oxidization capability of Cu(II) ion is responsible for the formation of S,S-2 because X-ray photoelectron spectroscopy (XPS) for the solid powder of reaction mixture of direct Cu(II) ion template synthesis implies that both Cu(I) and Cu(II) species are present. In fact, corresponding [2 + 2] dinuclear Cu(II) macrocycles and even metal-free macrocycles unsuitable for direct synthesis can be obtained via Cd(II) → Cu(II) transmetalation and Na2S demetalation verified by ESI-MS and UV-vis spectra. In addition, control experiments indicate that the synthesis of metal-free macrocycles via the direct nontemplate method merely results in the mixture of multiple components of [1 + 1], [2 + 2], and [3 + 3] Schiff-base macrocycles, and they are difficult to isolate.
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Affiliation(s)
- Pei-Chen Zhao
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu Province 210093, P. R. China
| | - Fei-Fan Chang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu Province 210093, P. R. China
| | - Fan-Da Feng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu Province 210093, P. R. China
| | - Wei Huang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu Province 210093, P. R. China.,Shenzhen Research Institute of Nanjing University, Shenzhen 518057, P. R. China
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8
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Soobrattee S, Zhai X, Nyamayaro K, Diaz C, Kelley P, Ebrahimi T, Mehrkhodavandi P. Dinucleating Amino-Phenolate Platform for Zinc Catalysts: Impact on Lactide Polymerization. Inorg Chem 2020; 59:5546-5557. [PMID: 32223228 DOI: 10.1021/acs.inorgchem.0c00250] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We report imine- and amine-based dinucleating ligands bearing a bisphenol backbone and explore their coordination chemistry with zinc to form zinc alkyl, alkoxide, acetate, and amide complexes. Full characterization of the complexes shows that this ligand framework can support dinuclear and trinuclear complexes. We explore the reactivity of the zinc alkyl and alkoxide complexes as catalysts for the ring opening polymerization of lactide and compared this reactivity to analogous mononuclear complexes. We show that 1) The amine-based complexes are more reactive than the imine-based analogues; 2) The trinuclear zinc alkyl species show unusual control and reproducibility for lactide polymerization; and 3) The extent of bimetallic cooperation is hampered by the ability of the ligand framework to form trinuclear clusters.
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Affiliation(s)
- Shazia Soobrattee
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Xiaofang Zhai
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Kudzanai Nyamayaro
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Carlos Diaz
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Paul Kelley
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Tannaz Ebrahimi
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Parisa Mehrkhodavandi
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
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9
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Chang FF, Li WQ, Feng FD, Huang W. Construction and Photoluminescent Properties of Schiff-Base Macrocyclic Mono-/Di-/Trinuclear Zn II Complexes with the Common 2-Ethylthiophene Pendant Arm. Inorg Chem 2019; 58:7812-7821. [PMID: 31185551 DOI: 10.1021/acs.inorgchem.9b00454] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new flexible 2-ethylthiophene pendant-armed dialdehyde (H2tdd) was reacted with 1,3-propanediamine, [( S, S),( R, R),(±)]-1,2-diaminocyclohexane, and 1,2-bis(2-aminoethoxy)ethane, giving birth to 36-membered [2 + 2] Schiff-base macrocyclic trinuclear ZnII complex 1, 18-membered [1 + 1] mononuclear ZnII macrocycles 2-4, chiral/racemic 34-membered [2 + 2] dinuclear ZnII complexes 5-9, and 46-membered [2 + 2] dinuclear ZnII macrocycles 10-12 via ZnII ion template-assisted Schiff-base condensation. It is worth mentioning that the secondary template effects for nitrate and halide counterions have been observed in the 1,3-propanediamine involved imine condensation. In all [2 + 2] ZnII macrocycles, dinuclear complexes 5-9 display a full-folded molecular conformation, while trinuclear complex 1 and dinuclear complexes 10-12 exhibit distinct half-folded structures in the presence or absence of intramolecular π-π stacking interactions between two phenolic rings of the dialdehyde component. Interestingly, a solvent-induced single-crystal-to-single-crystal transformation was first achieved for two types of solvated mononuclear macrocycles 3a and 3b (H2O vs CH3CN) with folded and unfolded ligand conformations. In addition, the photoluminescent properties were studied for this family of Schiff-base macrocyclic ZnII complexes as well as the dialdehyde precursor H2tdd.
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Affiliation(s)
- Fei-Fan Chang
- State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing , Jiangsu Province , 210093 , P. R. China
| | - Wen-Qi Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Science , Nanjing University , Nanjing 210093 , P. R. China
| | - Fan-Da Feng
- State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing , Jiangsu Province , 210093 , P. R. China
| | - Wei Huang
- State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing , Jiangsu Province , 210093 , P. R. China
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10
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The conformational space of diphenylamine-2,2'-dicarboxaldehyde. “Whoever reports a saying in the name of the one who said it brings redemption to the world.”. Struct Chem 2019. [DOI: 10.1007/s11224-019-1291-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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11
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Pankhurst JR, Paul S, Zhu Y, Williams CK, Love JB. Polynuclear alkoxy-zinc complexes of bowl-shaped macrocycles and their use in the copolymerisation of cyclohexene oxide and CO 2. Dalton Trans 2019; 48:4887-4893. [PMID: 30896006 DOI: 10.1039/c9dt00595a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The reactions between alcohols and the tetranuclear ethyl-Zn complexes of an ortho-phenylene-bridged polypyrrole macrocycle, Zn4Et4(L1) 1 and the related anthracenyl-bridged macrocyclic complex, Zn4Et4(THF)4(L2) 2 have been studied. With long-chain alcohols such as n-hexanol, the clean formation of the tetranuclear hexoxide complex Zn4(OC6H13)4(L1) 3 occurs. In contrast, the use of shorter-chain alcohols such as i-propanol results in the trinuclear complex Zn3(μ2-OiPr)2(μ3-OiPr)(HL1) 4 that arises from demetalation; this complex was characterised by X-ray crystallography. The clean formation of these polynuclear zinc clusters allowed a study of their use as catalysts in the ring-opening copolymerisation (ROCOP) reaction between cyclohexene oxide and CO2. In situ reactions involving the pre-catalyst 1 and n-hexanol formed the desired polymer with the best selectivity for polycarbonate (90%) at 30 atm CO2, whilst the activity and performance of pre-catalyst 2 was poor in comparison.
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Affiliation(s)
- James R Pankhurst
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK.
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12
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13
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Paparo A, Silvia JS, Spaniol TP, Okuda J, Cummins CC. Countercation Effect on CO
2
Binding to Oxo Titanate with Bulky Anilide Ligands. Chemistry 2018; 24:17072-17079. [DOI: 10.1002/chem.201803265] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Albert Paparo
- Institute of Inorganic ChemistryRWTH Aachen University Landoltweg 1 52074 Aachen Germany
- Current address: School of ChemistryMonash University PO Box 23 VIC 3800 Australia
| | - Jared S. Silvia
- Department of ChemistryMassachusetts Institute of Technology 77 Massachusetts Ave Cambridge MA 02139 USA
| | - Thomas P. Spaniol
- Institute of Inorganic ChemistryRWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Jun Okuda
- Institute of Inorganic ChemistryRWTH Aachen University Landoltweg 1 52074 Aachen Germany
| | - Christopher C. Cummins
- Department of ChemistryMassachusetts Institute of Technology 77 Massachusetts Ave Cambridge MA 02139 USA
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14
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Lilley LM, Du K, Krzyaniak MD, Parigi G, Luchinat C, Harris TD, Meade TJ. Effect of Magnetic Coupling on Water Proton Relaxivity in a Series of Transition Metal Gd III Complexes. Inorg Chem 2018; 57:5810-5819. [PMID: 29714477 DOI: 10.1021/acs.inorgchem.8b00120] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A fundamental challenge in the design of bioresponsive (or bioactivated) GdIII-based magnetic resonance (MR) imaging probes is the considerable background signal present in the "preactivated" state that arises from outer-sphere relaxation processes. When sufficient concentrations of a bioresponsive agent are present (i.e., a detectable signal in the image), the inner- and outer-sphere contributions to r1 may be misinterpreted to conclude that the agent has been activated, when it has not. Of the several parameters that determine the observed MR signal of an agent, only the electron relaxation time ( T1e) impacts both the inner- and outer-sphere relaxation. Therefore, strategies to minimize this background signal must be developed to create a near zero-background (or truly "off" state) of the agent. Here, we demonstrate that intramolecular magnetic exchange coupling when GdIII is coupled to a paramagnetic transition metal provides a means to overcome the contribution of second- and outer-sphere contributions to the observed relaxivity. We have prepared a series of complexes with the general formula LMLn(μ-O2CCH3)(O2CCH3)2 (M = Co, Cu, Zn). Solid-state magnetic susceptibility measurements reveal significant magnetic coupling between GdIII and the transition metal ion. Nuclear magnetic relaxation dispersion (NMRD) analysis confirms that the observed differences in relaxivity are associated with the modulation of T1e at GdIII. These results clearly demonstrate that magnetic exchange coupling between GdIII and a transition metal ion can provide a significant decrease in T1e (and therefore the relaxivity of GdIII). This design strategy is being exploited to prepare new generations of preclinical bioresponsive MR imaging probes with near zero-background.
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Affiliation(s)
| | | | | | - Giacomo Parigi
- Department of Chemistry and Magnetic Resonance Center (CERM) , University of Florence , Via L. Sacconi 6 , 50019 Sesto Fiorentino , Italy
| | - Claudio Luchinat
- Department of Chemistry and Magnetic Resonance Center (CERM) , University of Florence , Via L. Sacconi 6 , 50019 Sesto Fiorentino , Italy
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15
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Malthus SJ, Cameron SA, Brooker S. Improved Access to 1,8-Diformyl-carbazoles Leads to Metal-Free Carbazole-Based [2 + 2] Schiff Base Macrocycles with Strong Turn-On Fluorescence Sensing of Zinc(II) Ions. Inorg Chem 2018; 57:2480-2488. [PMID: 29442503 DOI: 10.1021/acs.inorgchem.7b02763] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Development of a new and high yielding synthetic route to 1,8-diformyl-carbazoles 3 (3a 3,6-di- tert-butyl substituted; 3b 3,6-unsubstituted) is reported. Use of a Heck coupling reaction, followed by ozonolysis, has greatly facilitated the preparation of these interesting head units in useful quantities. An initial foray into the new generations of Schiff base macrocycles that ready access to these head units (3) opens up, has led to the direct (i.e., metal-free) synthesis of two [2 + 2] macrocycles from 3a or 3b with 1,2-diaminoethane, H2LtBu (4a) and H2LH (4b), respectively, obtained as yellow powders in high yields (87-88%). The dizinc complex [Zn2LH(OAc)2] (5b) was isolated as a bright yellow solid in 83% yield, by 1:2:2 reaction of H2LH with zinc(II) acetate and triethylamine. Aldehydes 3a and 3b, macrocycle H2LH, and complex [Zn2LH(OAc)2] (5b) have been structurally characterized. The carbazole NH makes bifurcated hydrogen bonds with the pair of flanking 1,8-diformyl-moieties in 3, or 1,8-diimine-moieties in H2LH, leading to a flat, all- cis conformation. The stepped conformation of the metal-free macrocycle H2LH is retained in [Zn2LH(OAc)2], despite deprotonation and binding of two zinc(II) centers within the two tridentate pockets. The N3O2 coordination of the zinc ions is completed by one μ1,1- and one μ1,3- bridging acetate anion. Excitation of nanomolar [Zn2LH(OAc)2] in DMF at 335 nm results in clearly visible blue fluorescence (λmax = 460 nm). Further studies on the H2LH macrocycle revealed turn-on fluorescence, with selectivity (over Ca2+, Mg2+ and a range of 3d dications) and nanomolar sensitivity for zinc(II) ions, highlighting one of the many potential applications for these new carbazole-based Schiff base macrocycles.
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Affiliation(s)
- Stuart J Malthus
- Department of Chemistry and the MacDiarmid Institute for Advanced Materials and Nanotechnology , University of Otago , P.O. Box 56 , Dunedin 9054 , New Zealand
| | - Scott A Cameron
- Department of Chemistry and the MacDiarmid Institute for Advanced Materials and Nanotechnology , University of Otago , P.O. Box 56 , Dunedin 9054 , New Zealand
| | - Sally Brooker
- Department of Chemistry and the MacDiarmid Institute for Advanced Materials and Nanotechnology , University of Otago , P.O. Box 56 , Dunedin 9054 , New Zealand
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16
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Transmetalation for Flexible Pendant-Armed Schiff-Base Macrocyclic Complexes Influenced by Halide Effects. Inorg Chem 2018; 57:1438-1448. [PMID: 29323889 DOI: 10.1021/acs.inorgchem.7b02835] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three 46-membered [2 + 2] pendant-armed Schiff-base macrocyclic dinuclear CdII and CuII complexes (2a, 2b, and 3b) and one 23-membered [1 + 1] CuII macrocycle 4a were prepared from the template-directed condensation reactions between 1,2-bis(2-aminoethoxy)-ethane and extended Cl-dialdehyde in the presence of CdX2 and CuX2 (X = Cl and Br), in which halide effects play important roles in the organization of final macrocyclic complexes in addition to the dominant influence of metal cations. Transmetalation was intensively studied among these CdII and CuII complexes with large and flexible macrocyclic ligands, including two previously synthesized dinuclear ZnII macrocycles (1a and 1b). Our results indicate that ZnII → CuII and CdII → CuII transmetalation proceeds more quickly than that from CdII to ZnII, and all the processes are found to be irreversible. It is noted that a [2 + 2] heterodinuclear CdIIZnII macrocyclic intermediate could be detected by ESI-MS together with [2 + 2] homodinuclear CdII and ZnII macrocyclic complexes. Furthermore, distinct halide behavior was observed in the in situ CdII → CuII and ZnII → CuII metal-ion exchange. That is to say, [2 + 2] macrocycles (1a and 2a) could be converted to [1 + 1] macrocycles 4a and 4b under the reflux condition in the case of CuCl2, accompanied by the configurational transformation from half-folded dinuclear ZnII and CdII to unfolded CuII macrocyclic skeleton. In contrast, CuBr2 leads to a highly efficient transmetalation to corresponding [2 + 2] dinuclear CuII complex 3b from both 1b and 2b no matter the experimental condition used.
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17
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Nagae H, Aoki R, Akutagawa SN, Kleemann J, Tagawa R, Schindler T, Choi G, Spaniol TP, Tsurugi H, Okuda J, Mashima K. Lanthanoidkomplexe mit Trizink-Kronenether als Katalysatoren für die alternierende Copolymerisation von Epoxid und CO2
: eine durch Carboxylat-Anionen kontrollierte Telomerisierung. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201709218] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Haruki Nagae
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Ryota Aoki
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Shin-nosuke Akutagawa
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Julian Kleemann
- Institut für Anorganische Chemie; RWTH Aachen; Landoltweg 1 52062 Aachen Deutschland
| | - Risa Tagawa
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Tobias Schindler
- Institut für Anorganische Chemie; RWTH Aachen; Landoltweg 1 52062 Aachen Deutschland
| | - Gyeongshin Choi
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Thomas P. Spaniol
- Institut für Anorganische Chemie; RWTH Aachen; Landoltweg 1 52062 Aachen Deutschland
| | - Hayato Tsurugi
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Jun Okuda
- Institut für Anorganische Chemie; RWTH Aachen; Landoltweg 1 52062 Aachen Deutschland
| | - Kazushi Mashima
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
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18
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Nagae H, Aoki R, Akutagawa SN, Kleemann J, Tagawa R, Schindler T, Choi G, Spaniol TP, Tsurugi H, Okuda J, Mashima K. Lanthanide Complexes Supported by a Trizinc Crown Ether as Catalysts for Alternating Copolymerization of Epoxide and CO2
: Telomerization Controlled by Carboxylate Anions. Angew Chem Int Ed Engl 2018; 57:2492-2496. [DOI: 10.1002/anie.201709218] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Haruki Nagae
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Ryota Aoki
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Shin-nosuke Akutagawa
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Julian Kleemann
- Institute of Inorganic Chemistry; RWTH Aachen University; Landoltweg 1 52062 Aachen Germany
| | - Risa Tagawa
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Tobias Schindler
- Institute of Inorganic Chemistry; RWTH Aachen University; Landoltweg 1 52062 Aachen Germany
| | - Gyeongshin Choi
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Thomas P. Spaniol
- Institute of Inorganic Chemistry; RWTH Aachen University; Landoltweg 1 52062 Aachen Germany
| | - Hayato Tsurugi
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
| | - Jun Okuda
- Institute of Inorganic Chemistry; RWTH Aachen University; Landoltweg 1 52062 Aachen Germany
| | - Kazushi Mashima
- Department of Chemistry; Graduate School of Engineering Science; Osaka University; Toyonaka Osaka 560-8531 Japan
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19
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Ghosh S, Spannenberg A, Mejía E. Cubane-Type Polynuclear Zinc Complexes Containing Tridentate Schiff
Base Ligands: Synthesis, Characterization, and Ring-Opening Polymerization Studies of rac
-Lactide and ε
-Caprolactone. Helv Chim Acta 2017. [DOI: 10.1002/hlca.201700176] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Swarup Ghosh
- Leibniz Institute for Catalysis; University of Rostock; Albert-Einstein-Str. 29a 18059 Rostock Germany
| | - Anke Spannenberg
- Leibniz Institute for Catalysis; University of Rostock; Albert-Einstein-Str. 29a 18059 Rostock Germany
| | - Esteban Mejía
- Leibniz Institute for Catalysis; University of Rostock; Albert-Einstein-Str. 29a 18059 Rostock Germany
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20
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Schäfer PM, Fuchs M, Ohligschläger A, Rittinghaus R, McKeown P, Akin E, Schmidt M, Hoffmann A, Liauw MA, Jones MD, Herres-Pawlis S. Highly Active N,O Zinc Guanidine Catalysts for the Ring-Opening Polymerization of Lactide. CHEMSUSCHEM 2017; 10:3547-3556. [PMID: 28779508 DOI: 10.1002/cssc.201701237] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 08/04/2017] [Indexed: 06/07/2023]
Abstract
New zinc guanidine complexes with N,O donor functionalities were prepared, characterized by X-Ray crystallography, and examined for their catalytic activity in the solvent-free ring-opening polymerization (ROP) of technical-grade rac-lactide at 150 °C. All complexes showed a high activity. The fastest complex [ZnCl2 (DMEGasme)] (C1) produced colorless poly(lactide) (PLA) after 90 min with a conversion of 52 % and high molar masses (Mw =69 100, polydispersity=1.4). The complexes were tested with different monomer-to-initiator ratios to determine the rate constant kp . Furthermore, a polymerization with the most active complex C1 was monitored by in situ Raman spectroscopy. Overall, conversion of up to 90 % can be obtained. End-group analysis was performed to clarify the mechanism. All four complexes combine robustness against impurities in the lactide with high polymerization rates, and they represent the fastest robust lactide ROP catalysts to date, opening new avenues to a sustainable ROP catalyst family for industrial use.
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Affiliation(s)
- Pascal M Schäfer
- Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Martin Fuchs
- Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Andreas Ohligschläger
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany
| | - Ruth Rittinghaus
- Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Paul McKeown
- Department of Chemistry, University of Bath, ClavertonDown, Bath, BA2 7AY, UK
| | - Enver Akin
- Fakultät für Naturwissenschaften, Department Chemie, Universität Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Maximilian Schmidt
- Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Alexander Hoffmann
- Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Marcel A Liauw
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany
| | - Matthew D Jones
- Department of Chemistry, University of Bath, ClavertonDown, Bath, BA2 7AY, UK
| | - Sonja Herres-Pawlis
- Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
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21
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Romain C, Garden JA, Trott G, Buchard A, White AJP, Williams CK. Di-Zinc-Aryl Complexes: CO 2 Insertions and Applications in Polymerisation Catalysis. Chemistry 2017; 23:7367-7376. [PMID: 28370511 PMCID: PMC5488170 DOI: 10.1002/chem.201701013] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Indexed: 11/05/2022]
Abstract
Two new di-zinc-aryl complexes, [LZn2 Ph2 ] and [LZn2 (C6 F5 )2 ], coordinated by a diphenol tetraamine macrocyclic ligand have been prepared and fully characterised, including by single-crystal X-ray diffraction experiments. The complexes' reactivities with monomers including carbon dioxide, cyclohexene oxide, phthalic anhydride, isopropanol and phenol were investigated using both experimental studies and density functional theory calculations. In particular, [LZn2 Ph2 ] readily inserts carbon dioxide to form a carboxylate, at 1 bar pressure, whereas [LZn2 (C6 F5 )2 ] does not react. Under these conditions [LZn2 Ph2 ] shows moderate activity in the ring-opening copolymerisation of cyclohexene oxide/carbon dioxide (TOF=20 h-1 ), cyclohexene oxide/phthalic anhydride (TOF=33 h-1 ) and the ring-opening polymerisations of rac-lactide (TOF=99 h-1 ) and ϵ-caprolactone (TOF=5280 h-1 ).
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Affiliation(s)
- Charles Romain
- Department of ChemistryImperial College LondonLondonSW7 2AZUK
| | | | - Gemma Trott
- Department of ChemistryChemistry Research LaboratoryUniversity of Oxford12 Mansfield RoadOxfordOX2 3TAUK
| | | | | | - Charlotte K. Williams
- Department of ChemistryChemistry Research LaboratoryUniversity of Oxford12 Mansfield RoadOxfordOX2 3TAUK
- Department of ChemistryImperial College LondonLondonSW7 2AZUK
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22
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Use of Metal Catalysts Bearing Schiff Base Macrocycles for the Ring Opening Polymerization (ROP) of Cyclic Esters. Catalysts 2017. [DOI: 10.3390/catal7050165] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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23
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Petersen TO, Weigel S, Kratzert D, Fischer A, Krossing I. Ethylzinc- and Zinc-bis-fluoroalkoxides. ChemistrySelect 2017. [DOI: 10.1002/slct.201601855] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Thies Olaf Petersen
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstr. 21 79104 Freiburg Germany
| | - Simon Weigel
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstr. 21 79104 Freiburg Germany
| | - Daniel Kratzert
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstr. 21 79104 Freiburg Germany
| | - Anna Fischer
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstr. 21 79104 Freiburg Germany
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie and Freiburger Materialforschungszentrum (FMF); Universität Freiburg; Albertstr. 21 79104 Freiburg Germany
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24
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Malthus SJ, Wilson RK, Vikas Aggarwal A, Cameron SA, Larsen DS, Brooker S. Carbazole-based N4-donor Schiff base macrocycles: obtained metal free and as Cu(ii) and Ni(ii) complexes. Dalton Trans 2017; 46:3141-3149. [DOI: 10.1039/c6dt04598g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Practical multi-step routes to 1,8-diformylcarbazole head units, and the first examples of Schiff base macrocycles derived from them, are reported. Like porphyrins, both macrocycles are shown to impose a strong ligand field.
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Affiliation(s)
- Stuart J. Malthus
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology
- Dunedin 9054
- New Zealand
| | - Rajni K. Wilson
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology
- Dunedin 9054
- New Zealand
| | - A. Vikas Aggarwal
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology
- Dunedin 9054
- New Zealand
| | - Scott A. Cameron
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology
- Dunedin 9054
- New Zealand
| | - David S. Larsen
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology
- Dunedin 9054
- New Zealand
| | - Sally Brooker
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology
- Dunedin 9054
- New Zealand
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25
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Metz A, Plothe R, Glowacki B, Koszalkowski A, Scheckenbach M, Beringer A, Rösener T, Michaelis de Vasconcellos J, Haase R, Flörke U, Hoffmann A, Herres-Pawlis S. Zinc Chloride Complexes with Aliphatic and Aromatic Guanidine Hybrid Ligands and Their Activity in the Ring-Opening Polymerisation ofd,l-Lactide. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600870] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Angela Metz
- Institut für Anorganische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Ramona Plothe
- Technische Universität Dortmund; Fakultät Chemie und Chemische Biologie; Otto-Hahn-Str. 6 44227 Dortmund Germany
| | - Britta Glowacki
- Technische Universität Dortmund; Fakultät Chemie und Chemische Biologie; Otto-Hahn-Str. 6 44227 Dortmund Germany
| | - Andreas Koszalkowski
- Ludwig-Maximilians-Universität München; Department of Chemistry; Butenandtstr. 5-13 81377 München Germany
| | - Michael Scheckenbach
- Ludwig-Maximilians-Universität München; Department of Chemistry; Butenandtstr. 5-13 81377 München Germany
| | - Andreas Beringer
- Ludwig-Maximilians-Universität München; Department of Chemistry; Butenandtstr. 5-13 81377 München Germany
| | - Thomas Rösener
- Institut für Anorganische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | | | - Roxana Haase
- Universität Paderborn, Anorganische Chemie; Department Chemie; Warburger Str. 100 33098 Paderborn Germany
| | - Ulrich Flörke
- Universität Paderborn, Anorganische Chemie; Department Chemie; Warburger Str. 100 33098 Paderborn Germany
| | - Alexander Hoffmann
- Institut für Anorganische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
| | - Sonja Herres-Pawlis
- Institut für Anorganische Chemie; RWTH Aachen University; Landoltweg 1 52074 Aachen Germany
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26
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Thevenon A, Romain C, Bennington MS, White AJP, Davidson HJ, Brooker S, Williams CK. Dizinc Lactide Polymerization Catalysts: Hyperactivity by Control of Ligand Conformation and Metallic Cooperativity. Angew Chem Int Ed Engl 2016; 55:8680-5. [PMID: 27295339 PMCID: PMC5089563 DOI: 10.1002/anie.201602930] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Indexed: 11/08/2022]
Abstract
Understanding how to moderate and improve catalytic activity is critical to improving degradable polymer production. Here, di- and monozinc catalysts, coordinated by bis(imino)diphenylamido ligands, show remarkable activities and allow determination of the factors controlling performance. In most cases, the dizinc catalysts significantly out-perform the monozinc analogs. Further, for the best dizinc catalyst, the ligand conformation controls activity: the catalyst with "folded" ligand conformation shows turnover frequency (TOF) values up to 60 000 h(-1) (0.1 mol % loading, 298 K, [LA]=1 m), whilst that with a "planar" conformation is much slower, under similar conditions (TOF=30 h(-1) ). Dizinc catalysts also perform very well under immortal conditions, showing improved control, and are able to tolerate loadings as low as 0.002 mol % whilst conserving high activity (TOF=12 500 h(-1) ).
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Affiliation(s)
- Arnaud Thevenon
- Department of Chemistry, Imperial College London, South Kensington, UK
| | - Charles Romain
- Department of Chemistry, Imperial College London, South Kensington, UK
| | | | - Andrew J P White
- Department of Chemistry, Imperial College London, South Kensington, UK
| | | | - Sally Brooker
- Department of Chemistry, University of Otago, Dunedin, New Zealand.
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27
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Thevenon A, Romain C, Bennington MS, White AJP, Davidson HJ, Brooker S, Williams CK. Dizinc Lactide Polymerization Catalysts: Hyperactivity by Control of Ligand Conformation and Metallic Cooperativity. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201602930] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Arnaud Thevenon
- Department of Chemistry; Imperial College London; South Kensington UK
| | - Charles Romain
- Department of Chemistry; Imperial College London; South Kensington UK
| | | | | | | | - Sally Brooker
- Department of Chemistry; University of Otago; Dunedin New Zealand
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28
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First row transition metal complexes of di-o-substituted-diarylamine-based ligands (including carbazoles, acridines and dibenzoazepines). Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.02.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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29
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Wang X, Dorcet V, Luo Y, Carpentier JF, Kirillov E. Synthesis and structure of the first discrete dinuclear cationic aluminum complexes. Dalton Trans 2016; 45:12346-51. [DOI: 10.1039/c6dt02360f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The preparation of discrete mono- and dicationic dinuclear aluminum complexes from the parent charge neutral dinuclear precursors has been studied. The first crystal structure of a dicationic dialuminum complex is reported.
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Affiliation(s)
- Xingbao Wang
- Institut des Sciences Chimiques de Rennes
- Organometallics: Materials and Catalysis laboratories
- UMR 6226 CNRS-Université de Rennes 1
- F-35042 Rennes Cedex
- France
| | - Vincent Dorcet
- Institut des Sciences Chimiques de Rennes
- Centre de diffraction X
- UMR 6226 CNRS-Université de Rennes 1
- F-35042 Rennes Cedex
- France
| | - Yi Luo
- State Key Laboratory of Fine Chemicals
- School of Pharmaceutical Science and Technology Dalian University of Technology
- Dalian 116024
- P. R. China
| | - Jean-Francois Carpentier
- Institut des Sciences Chimiques de Rennes
- Organometallics: Materials and Catalysis laboratories
- UMR 6226 CNRS-Université de Rennes 1
- F-35042 Rennes Cedex
- France
| | - Evgueni Kirillov
- Institut des Sciences Chimiques de Rennes
- Organometallics: Materials and Catalysis laboratories
- UMR 6226 CNRS-Université de Rennes 1
- F-35042 Rennes Cedex
- France
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