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Madeira F, Veiros LF, Alves LG, Martins AM. Synthesis, Characterization, and Reactivity Studies of New Cyclam-Based Y(III) Complexes. Molecules 2023; 28:7998. [PMID: 38138486 PMCID: PMC10745738 DOI: 10.3390/molecules28247998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
[(Bn2Cyclam)Y(N(SiMe3)2)] was prepared by reaction of H2Bn2Cyclam with Y[N(SiMe3)2]3. The protonation of the macrocycle ligand in [(Bn2Cyclam)Y(N(SiMe3)2)] is observed upon reaction with [HNMe3][BPh4] leading to the formation of [(HBn2Cyclam)Y(N(SiMe3)2)][BPh4]. DFT analysis of [(Bn2Cyclam)Y(N(SiMe3)2)] showed that the HOMO is located on the anionic nitrogen atoms of the cyclam ring indicating that protonation follows orbital control. Addition of H2Bn2Cyclam and H2(3,5-tBu2Bn)2Cyclam to a 1:3 mixture of YCl3 and LiCH2SiMe3 in THF resulted in the formation of [((C6H4CH2)BnCyclam)Y(THF)(µ-Cl)Li(THF)2] and [Y{(η3-3,5-tBu2Bn)2Cyclam}Li(THF)], respectively. The reaction of H23,5-tBu2Bn2Cyclam with Y(CH2SiMe3)3(THF)2 was studied and monitored by a temperature variation NMR experiment revealing the formation of [(3,5-tBu2Bn2Cyclam)Y(CH2SiMe3)]. Preliminary catalytic assays have shown that [Y{(η3-3,5-tBu2Bn)2Cyclam}Li(THF)] is a very efficient catalyst for the intramolecular hydroamination of 2,2-diphenyl-pent-4-enylamine.
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Affiliation(s)
- Filipe Madeira
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal
| | - Luis F. Veiros
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal
| | - Luis G. Alves
- Centro de Química Estrutural, Associação do Instituto Superior Técnico para a Investigação e Desenvolvimento, Av. António José de Almeida nº 12, 1000-043 Lisbon, Portugal
| | - Ana M. Martins
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal
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2
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N3/4-pyridinyl Schiff base copper(II) benzoate complexes: synthesis, crystal structures and ring-opening polymerization studies. TRANSIT METAL CHEM 2022. [DOI: 10.1007/s11243-022-00494-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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3
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Paradiso V, Capaccio V, Lamparelli DH, Capacchione C. [OSSO]-bisphenolate metal complexes: A powerful and versatile tool in polymerization catalysis. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213644] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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4
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Diteepeng N, Wilson IAP, Buffet JC, Turner ZR, O'Hare D. l- and rac-lactide polymerisation using scandium and aluminium permethylindenyl complexes. Polym Chem 2020. [DOI: 10.1039/d0py00980f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Scandium and aluminium constrained geometry permethylindenyl complexes are reported and their lactide polymerisation study discussed.
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Affiliation(s)
- Nichabhat Diteepeng
- Chemistry Research Laboratory
- Department of Chemistry
- University of Oxford
- OX1 3TA Oxford
- UK
| | - Isobel A. P. Wilson
- Chemistry Research Laboratory
- Department of Chemistry
- University of Oxford
- OX1 3TA Oxford
- UK
| | - Jean-Charles Buffet
- Chemistry Research Laboratory
- Department of Chemistry
- University of Oxford
- OX1 3TA Oxford
- UK
| | - Zoë R. Turner
- Chemistry Research Laboratory
- Department of Chemistry
- University of Oxford
- OX1 3TA Oxford
- UK
| | - Dermot O'Hare
- Chemistry Research Laboratory
- Department of Chemistry
- University of Oxford
- OX1 3TA Oxford
- UK
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5
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Lyubov DM, Tolpygin AO, Trifonov AA. Rare-earth metal complexes as catalysts for ring-opening polymerization of cyclic esters. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.04.013] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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6
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Electronic influence of ligand substituents in the ring-opening polymerization of l-Lactide promoted by OSSO-type zirconium complexes. MOLECULAR CATALYSIS 2019. [DOI: 10.1016/j.mcat.2019.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Rajashekhar B, Mandal M, Chakraborty D, Ramkumar V. Homoleptic Zr and Hf Complexes of Imino/Bis(imino)phenoxide Scaffolds: Synthesis, Structural Characterization and Their Catalytic Activity in the ROP of Cyclic Esters. ChemistrySelect 2017. [DOI: 10.1002/slct.201701602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Bijja Rajashekhar
- Department of Chemistry; Indian Institute of Technology Madras; Chennai- 600 036, Tamil Nadu India
| | - Mrinmay Mandal
- Department of Chemistry; Indian Institute of Technology Patna; Bihta 801103, Bihar India
| | - Debashis Chakraborty
- Department of Chemistry; Indian Institute of Technology Madras; Chennai- 600 036, Tamil Nadu India
| | - Venkatachalam Ramkumar
- Department of Chemistry; Indian Institute of Technology Madras; Chennai- 600 036, Tamil Nadu India
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8
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Hu C, Louisy E, Fontaine G, Bonnet F. Cyclic versus linear polylactide: Straightforward access using a single catalyst. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/pola.28699] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Chi Hu
- Unité de Catalyse et Chimie du Solide, CNRS, UMR 8181, Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Université Lille 1; Villeneuve d'Ascq 59655 France
- Unité Matériaux Et Transformation, CNRS, UMR 8207, Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Université Lille 1; Villeneuve d'Ascq 59652 France
| | - Elodie Louisy
- Unité de Catalyse et Chimie du Solide, CNRS, UMR 8181, Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Université Lille 1; Villeneuve d'Ascq 59655 France
- Unité Matériaux Et Transformation, CNRS, UMR 8207, Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Université Lille 1; Villeneuve d'Ascq 59652 France
| | - Gaëlle Fontaine
- Unité Matériaux Et Transformation, CNRS, UMR 8207, Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Université Lille 1; Villeneuve d'Ascq 59652 France
| | - Fanny Bonnet
- Unité de Catalyse et Chimie du Solide, CNRS, UMR 8181, Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Université Lille 1; Villeneuve d'Ascq 59655 France
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9
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Duan YL, He JX, Wang W, Zhou JJ, Huang Y, Yang Y. Synthesis and characterization of dinuclear rare-earth complexes supported by amine-bridged bis(phenolate) ligands and their catalytic activity for the ring-opening polymerization of l-lactide. Dalton Trans 2016; 45:10807-20. [PMID: 27294827 DOI: 10.1039/c6dt01486k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactions of amine-bridged bis(phenolate) protio-ligands N,N-bis(3,5-di-tert-butyl-2-hydroxybenzyl)aminoacetic acid (L(1)-H3) and N,N-bis[3,5-bis(α,α'-dimethylbenzyl)-2-hydroxybenzyl]aminoacetic acid (L(2)-H3), with 1 equiv. M[N(SiMe3)2]3 (M = La, Nd, Sm, Gd, Y) in THF at room temperature yielded the neutral rare-earth complexes [M2(L)2(THF)4] (L = L(1), M = La (), Nd (), Sm (), Gd (), Y (); L = L(2), M = La (), Nd (), Sm (), Gd (), Y ()). All of these complexes were characterized by single-crystal X-ray diffraction, elemental analysis and in the case of yttrium and lanthanum complexes, (1)H NMR spectroscopy. The molecular structure of revealed dinuclear species in which the eight-coordinate lanthanum centers were bonded to two oxygen atoms of two THF molecules, to three oxygen atoms and one nitrogen atom of one L(1) ligand, and two oxygen atoms of the carboxyl group of another. Complexes were also dinuclear species containing seven-coordinate metal centers similar to , albeit with bonding to one rather than two carboxyl group oxygens of another ligand. Further treatment of with excess benzyl alcohol provided dinuclear complex [La2(L(1))2(BnOH)6] (), in which each lanthanum ion is eight-coordinate, bonded to three oxygen atoms and one nitrogen atom of one ligand, three oxygen atoms of three BnOH molecules, as well as one oxygen atom of bridging carboxyl group of the other ligand. In the presence of BnOH, complexes efficiently catalyzed the ring-opening polymerization of l-lactide in a controlled manner and gave polymers with relatively narrow molecular weight distributions. The kinetic and mechanistic studies associated with the ROP of l-lactide using /BnOH initiating system have been performed.
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Affiliation(s)
- Yu-Lai Duan
- Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, P. R. China.
| | - Jia-Xuan He
- Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, P. R. China.
| | - Wei Wang
- Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, P. R. China.
| | - Jing-Jing Zhou
- Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, P. R. China.
| | - Yong Huang
- Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, P. R. China.
| | - Ying Yang
- Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, P. R. China.
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10
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Synthesis and structure characterization of bis- and mono(amidate) lanthanide (Ln = La, Gd) complexes and their application in the polymerization of ε-caprolactone. J Organomet Chem 2016. [DOI: 10.1016/j.jorganchem.2016.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Meduri A, Cozzolino M, Milione S, Press K, Sergeeva E, Tedesco C, Mazzeo M, Lamberti M. Yttrium and aluminium complexes bearing dithiodiolate ligands: synthesis and application in cyclic ester polymerization. Dalton Trans 2015; 44:17990-8000. [PMID: 26406112 DOI: 10.1039/c5dt02938d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Yttrium and aluminium complexes of two dithiodiolate ligands that feature different bridges (CF3)2C(OH)CH2SRSCH2C(OH)(CF3)2 (L(1)-H2, R = CH2CH2 and L(2)-H2, R = C6H4) were synthesized in good yields by reacting tris(silylamide)yttrium or trimethylaluminium with one equivalent of the proligand. All complexes were characterized by NMR and elemental analysis, and single-crystal X-ray structural analysis was also performed for one of the yttrium complexes. The catalytic activities of the four complexes in the ring-opening polymerization of ε-caprolactone and rac-lactide have been investigated. Furthermore, DOSY experiment and DFT calculations have been carried out to determine the structure of the isopropoxo derivative of the complex L(2)Y amide.
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Affiliation(s)
- A Meduri
- Dipartimento di Chimica e Biologia, Università di Salerno, via Giovanni Paolo II 132, I-84084, Fisciano, Salerno, Italy
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12
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Bakewell C, White AJP, Long NJ, Williams CK. Scandium and Yttrium Phosphasalen Complexes as Initiators for Ring-Opening Polymerization of Cyclic Esters. Inorg Chem 2015; 54:2204-12. [DOI: 10.1021/ic5027015] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Clare Bakewell
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Andrew J. P. White
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Nicholas J. Long
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
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13
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Zeng T, Qian Q, Zhao B, Yuan D, Yao Y, Shen Q. Synthesis and characterization of rare-earth metal guanidinates stabilized by amine-bridged bis(phenolate) ligands and their application in the controlled polymerization of rac-lactide and rac-β-butyrolactone. RSC Adv 2015. [DOI: 10.1039/c5ra10151d] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Eight rare-earth metal guanidinates supported by a versatile family of bridged bis(phenolate) ligands were synthesized, and their application in initiating stereoselective ROP of rac-lactide and rac-β-butyrolactone were investigated and compared.
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Affiliation(s)
- Tinghua Zeng
- Key Laboratory of Organic Synthesis of Jiangsu Province and Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
| | - Qinqin Qian
- Key Laboratory of Organic Synthesis of Jiangsu Province and Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
| | - Bei Zhao
- Key Laboratory of Organic Synthesis of Jiangsu Province and Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
| | - Dan Yuan
- Key Laboratory of Organic Synthesis of Jiangsu Province and Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
| | - Yingming Yao
- Key Laboratory of Organic Synthesis of Jiangsu Province and Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
| | - Qi Shen
- Key Laboratory of Organic Synthesis of Jiangsu Province and Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
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14
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Della Monica F, Luciano E, Buonerba A, Grassi A, Milione S, Capacchione C. Poly(lactide-co-ε-caprolactone) copolymers prepared using bis-thioetherphenolate group 4 metal complexes: synthesis, characterization and morphology. RSC Adv 2014. [DOI: 10.1039/c4ra10255j] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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15
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Zhou H, Jiang Y, Chen M, Wang Y, Yao Y, Wu B, Cui D. Synthesis and characterization of lanthanide amides bearing phenoxy(quinolinyl)amide ligand and their application in the ring-opening polymerization of 1,4-dioxan-2-one. J Organomet Chem 2014. [DOI: 10.1016/j.jorganchem.2014.04.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Chapurina Y, Klitzke J, Casagrande Jr. ODL, Awada M, Dorcet V, Kirillov E, Carpentier JF. Scandium versus yttrium{amino-alkoxy-bis(phenolate)} complexes for the stereoselective ring-opening polymerization of racemic lactide and β-butyrolactone. Dalton Trans 2014; 43:14322-33. [DOI: 10.1039/c4dt01206b] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Della Monica F, Luciano E, Roviello G, Grassi A, Milione S, Capacchione C. Group 4 Metal Complexes Bearing Thioetherphenolate Ligands. Coordination Chemistry and Ring-Opening Polymerization Catalysis. Macromolecules 2014. [DOI: 10.1021/ma5003358] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Francesco Della Monica
- Department
of Chemistry and Biology, University of Salerno, via Giovanni Paolo II, 132 Fisciano I-84084, Salerno, Italy
| | - Ermanno Luciano
- Department
of Chemistry and Biology, University of Salerno, via Giovanni Paolo II, 132 Fisciano I-84084, Salerno, Italy
| | - Giuseppina Roviello
- Department
of Engeneering, University of Naples, Parthenope Centro Direzionale Napoli Isola C4, 80143 Napoli, Italy
| | - Alfonso Grassi
- Department
of Chemistry and Biology, University of Salerno, via Giovanni Paolo II, 132 Fisciano I-84084, Salerno, Italy
| | - Stefano Milione
- Department
of Chemistry and Biology, University of Salerno, via Giovanni Paolo II, 132 Fisciano I-84084, Salerno, Italy
| | - Carmine Capacchione
- Department
of Chemistry and Biology, University of Salerno, via Giovanni Paolo II, 132 Fisciano I-84084, Salerno, Italy
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18
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Mou Z, Liu B, Liu X, Xie H, Rong W, Li L, Li S, Cui D. Efficient and Heteroselective Heteroscorpionate Rare-Earth-Metal Zwitterionic Initiators for ROP of rac-Lactide: Role of σ-Ligand. Macromolecules 2014. [DOI: 10.1021/ma500209t] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Zehuai Mou
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People’s Republic of China
- University
of
Chinese Academy of Sciences, Changchun Branch, Changchun 130022, People’s Republic of China
| | - Bo Liu
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People’s Republic of China
| | - Xinli Liu
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People’s Republic of China
| | - Hongyan Xie
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People’s Republic of China
- University
of
Chinese Academy of Sciences, Changchun Branch, Changchun 130022, People’s Republic of China
| | - Weifeng Rong
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People’s Republic of China
- University
of
Chinese Academy of Sciences, Changchun Branch, Changchun 130022, People’s Republic of China
| | - Lei Li
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People’s Republic of China
- University
of
Chinese Academy of Sciences, Changchun Branch, Changchun 130022, People’s Republic of China
| | - Shihui Li
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People’s Republic of China
| | - Dongmei Cui
- State
Key Laboratory of Polymer Physics and Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People’s Republic of China
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Tsai CY, Du HC, Chang JC, Huang BH, Ko BT, Lin CC. Ring-opening polymerization of cyclic esters initiated by zirconium, titanium and yttrium complexes. RSC Adv 2014. [DOI: 10.1039/c4ra00201f] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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20
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Pappalardo D, Bruno M, Lamberti M, Mazzeo M, Pellecchia C. Ring-opening polymerization of ɛ-caprolactone and lactides promoted by salan- and salen-type yttrium amido complexes. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcata.2013.08.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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21
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Pilone A, Lamberti M, Mazzeo M, Milione S, Pellecchia C. Ring-opening polymerization of cyclic esters by phenoxy-thioether complexes derived from biocompatible metals. Dalton Trans 2013; 42:13036-47. [PMID: 23872640 DOI: 10.1039/c3dt51219c] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of novel Mg(II) and Zn(II) complexes of the form LMX or L2M, supported by phenoxy-thioether ligands bearing different substituents at the ortho position of the thiophenol rings [L(-) = 4,6-tBu2-OC6H2-2-CH2S(2-R-C6H4)(-)] [M = Zn, R = H, X = N(SiMe3)2 (1) and X = Et (2); M = Mg, X = n-Bu, R = H (3), R = CH3 (4), R = Br (5); M = Mg, R = H (6)], were synthesized and characterized. Reaction of the proper zinc precursor (Zn[N(SiHMe2)2]2 or ZnEt2) with one equivalent of the phenoxy-thioether proligand produced the corresponding amido (1) and ethyl (2) zinc complexes in high yields. The monoalkylmagnesium complexes (3-5) were all obtained by butane elimination reaction of the dialkylmagnesium reagent, Mg(n-Bu)2, with one equivalent of the proligand in good yields. The homoleptic complex 6 was obtained by reaction of 0.5 equivalent of Mg(n-Bu)2 and the proper proligand. Variable temperature (1)H NMR studies performed on 2 and 3 demonstrated that the named complexes are involved in fluxional processes concerning a fast conformational change of the six-membered metallacycle. DOSY (Diffusion Ordered SpectroscopY) (1)H experiments and ligand scrambling strongly suggested that complexes 1-6 exist as dimeric species in solution. All complexes were active as catalysts in the ring-opening polymerization of cyclic esters. In particular, magnesium complexes showed superior ε-caprolactone and lactide ROP behavior in terms of activity, control of molecular weights and molecular weight distributions.
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Affiliation(s)
- Alessia Pilone
- Department of Chemistry and Biology, University of Salerno, I-84084, via Ponte don Melillo, Fisciano, Salerno, Italy.
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