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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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Boyd EA, Peters JC. Sm(II)-Mediated Proton-Coupled Electron Transfer: Quantifying Very Weak N-H and O-H Homolytic Bond Strengths and Factors Controlling Them. J Am Chem Soc 2022; 144:21337-21346. [PMID: 36346706 PMCID: PMC10281198 DOI: 10.1021/jacs.2c09580] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Coordination of alcohols to the single-electron reductant samarium diiodide (SmI2) results in substantial O-H bond weakening, affording potent proton-coupled electron transfer (PCET) reagents. However, poorly defined speciation of SmI2 in tetrahydrofuran (THF)/alcohol mixtures limits reliable thermodynamic analyses of such systems. Rigorous determination of bond dissociation free energy (BDFE) values in such Sm systems, important to evaluating their reactivity profiles, motivates studies of model Sm systems where contributing factors can be teased apart. Here, a bulky and strongly chelating macrocyclic ligand ((tBu2ArOH)2Me2cyclam) maintains solubility, eliminates dimerization pathways, and facilitates clean electrochemical behavior in a well-defined functional model for the PCET reactivity of SmII with coordinating proton sources. Direct measurement of thermodynamic parameters enables reliable experimental estimation of the BDFEs in 2-pyrrolidone and MeOH complexes of ((tBu2ArO)2Me2cyclam)SmII, thereby revealing exceptionally weak N-H and O-H BDFEs of 27.2 and <24.1 kcal mol-1, respectively. Expanded thermochemical cycles reveal that this bond weakening stems from the very strongly reducing SmII center and the formation of strong SmIII-alkoxide (and -pyrrolidonate) interactions in the PCET products. We provide a detailed analysis comparing these BDFE values with those that have been put forward for SmI2 in THF in the presence of related proton donors. We suggest that BDFE values for the latter systems may in fact be appreciably higher than the system described herein. Finally, protonation and electrochemical reduction steps necessary for the regeneration of the PCET donors from SmIII-alkoxides are demonstrated, pointing to future strategies aimed at achieving (electro)catalytic turnover using SmII-based PCET reagents.
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Affiliation(s)
- Emily A Boyd
- Division of Chemistry and Chemical Engineering, California Institute of Technology (Caltech), Pasadena, California 91125, United States
| | - Jonas C Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology (Caltech), Pasadena, California 91125, United States
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Marszałek-Harych A, Trybuła D, Jędrzkiewicz D, Ejfler J. Scrabbling around in Synthetic Nuances Managing Sodium Compounds: Bisphenol/Bisnaphthol Synthesis by Hydroxyl Group Masking. Inorg Chem 2020; 59:6895-6904. [PMID: 32353236 PMCID: PMC7467675 DOI: 10.1021/acs.inorgchem.0c00310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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A unique
method of bisphenol/bisnaphthol synthesis is being proposed,
serendipitously discovered in the course of the careful analysis of
an aminophenol methylation reaction. The insightful exploration of
the synthesis of N- or O-methylated species, originating from functionalized
phenols obtained by a conventional strategy, provided the opportunity
to discover an unexpected reaction pathway yielding various bisphenols.
Sodium complexes were found to be crucial intermediates in the synthetic
scenario. Their formation, which is usually an imperceptive step,
was substantial for the productive outcome of functional group protection.
Thorough exploration revealed an essential structural motif of aminophenolate,
necessary for the successful outcome of the reaction, and also enabled
establishing the limitations of the new method. The work demonstrated
that a slight change in the perspective and close inspection of the
synthetic nuances can answer the important question concerning what
a specific target-oriented synthesis strategy is lacking. The protection of the hydroxyl group of aminophenols with
use of MeI—a general and, in many cases, excellent methylation
reagent—was investigated. In-depth understanding of the mechanistic
aspects of methyl protective group incorporation provided a practical
guide for its application in organic synthesis, but it also opened
a new route for the synthesis of an original group of bisphenols.
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Affiliation(s)
| | - Danuta Trybuła
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
| | - Dawid Jędrzkiewicz
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
| | - Jolanta Ejfler
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
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4
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Mewis RE, Archibald SJ. Side-bridged cyclam transition metal complexes bearing a phenolic ether or a phenolate pendent arm. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Li C, Deng ZP, Huo LH, Gao S. Cooperative effects of metal cations and coordination modes on luminescent s-block metal–organic complexes constructed from V-shaped 4,4′-sulfonyldiphenol. CrystEngComm 2018. [DOI: 10.1039/c8ce01591k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thirteen s-block metal–organic complexes with different supramolecular networks arising from the coordination modes of the ligands and properties of the metal cations have been synthesized and exhibit violet and blue luminescence in the solid state at room temperature.
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Affiliation(s)
- Cheng Li
- Key Laboratory of Functional Inorganic Material Chemistry
- Ministry of Education
- School of Chemistry and Materials Science
- Heilongjiang University
- Harbin 150080
| | - Zhao-Peng Deng
- Key Laboratory of Functional Inorganic Material Chemistry
- Ministry of Education
- School of Chemistry and Materials Science
- Heilongjiang University
- Harbin 150080
| | - Li-Hua Huo
- Key Laboratory of Functional Inorganic Material Chemistry
- Ministry of Education
- School of Chemistry and Materials Science
- Heilongjiang University
- Harbin 150080
| | - Shan Gao
- Key Laboratory of Functional Inorganic Material Chemistry
- Ministry of Education
- School of Chemistry and Materials Science
- Heilongjiang University
- Harbin 150080
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6
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1,8-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-4,11-dibenzyl-1,4,8,11-tetraazacyclotetradecane. MOLBANK 2017. [DOI: 10.3390/m963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Maria L, Sousa VR, Santos IC, Mora E, Marçalo J. Synthesis and structural characterization of polynuclear divalent ytterbium complexes supported by a bis(phenolate) cyclam ligand. Polyhedron 2016. [DOI: 10.1016/j.poly.2016.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Maria L, Soares M, Santos IC, Sousa VR, Mora E, Marçalo J, Luzyanin KV. A novel samarium(ii) complex bearing a dianionic bis(phenolate) cyclam ligand: synthesis, structure and electron-transfer reactions. Dalton Trans 2016; 45:3778-90. [PMID: 26818107 DOI: 10.1039/c5dt04647e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The reaction of the hexadentate dianionic 1,4,8,11-tetraazacyclotetradecane-based bis(phenolate) ligand, (tBu2ArO)2Me2-cyclam(2-), with [SmI2(thf )2] in thf resulted in the formation of the divalent samarium complex [Sm(κ(6)-{(tBu2ArO)2Me2-cyclam})] (1). X-ray diffraction studies revealed that after recrystallization from n-hexane/thf complex 1 has a monomeric structure and does not contain thf molecules coordinated to the Sm(II) center. However, UV-vis and (1)H NMR spectroscopy of 1 evidenced the formation of thf-solvated complexes in neat thf. Reductive studies show that complex 1 can act as a single electrontransfer reagent and form well-defined Sm(III) species. The reaction of 1 with several substrates, namely, TlBPh4, pyridine N-oxide, OPPh3, SPPh3 and bipyridines, are reported. Spectroscopy studies, including NMR, and single crystal X-ray diffraction data are in agreement with the formation of cationic Sm(III) species, monochalcogenide bridged Sm(III) complexes and Sm(III) complexes with bipyridine radical ligand, respectively.
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Affiliation(s)
- Leonor Maria
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal.
| | - Marina Soares
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal. and Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Isabel C Santos
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal.
| | - Vânia R Sousa
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal.
| | - Elsa Mora
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal.
| | - Joaquim Marçalo
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal.
| | - Konstantin V Luzyanin
- Institute of Chemistry, Saint Petersburg State University, Universitetsky pr. 26, 198504 Saint Petersburg, Russian Federation and Department of Chemistry, University of Liverpool, Crown Street, L69 7ZD, Liverpool, UK
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Rodríguez-Rodríguez A, Regueiro-Figueroa M, Esteban-Gómez D, Tripier R, Tircsó G, Kálmán FK, Bényei AC, Tóth I, Blas AD, Rodríguez-Blas T, Platas-Iglesias C. Complexation of Ln3+ Ions with Cyclam Dipicolinates: A Small Bridge that Makes Huge Differences in Structure, Equilibrium, and Kinetic Properties. Inorg Chem 2016; 55:2227-39. [DOI: 10.1021/acs.inorgchem.5b02627] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Aurora Rodríguez-Rodríguez
- Grupo QUICOOR,
Centro de Investigaciones Científicas Avanzadas (CICA) and
Departamento de Química Fundamental, Universidade da Coruña, Campus
da Zapateira, Rúa da Fraga 10, 15008 A Coruña, Spain
- Université de Bretagne Occidentale, UMR-CNRS 6521, UFR des Sciences et Techniques, 6 avenue Victor le Gorgeu, C.S. 93837, 29238 Brest, Cedex 3, France
| | - Martín Regueiro-Figueroa
- Grupo QUICOOR,
Centro de Investigaciones Científicas Avanzadas (CICA) and
Departamento de Química Fundamental, Universidade da Coruña, Campus
da Zapateira, Rúa da Fraga 10, 15008 A Coruña, Spain
| | - David Esteban-Gómez
- Grupo QUICOOR,
Centro de Investigaciones Científicas Avanzadas (CICA) and
Departamento de Química Fundamental, Universidade da Coruña, Campus
da Zapateira, Rúa da Fraga 10, 15008 A Coruña, Spain
| | - Raphaël Tripier
- Université de Bretagne Occidentale, UMR-CNRS 6521, UFR des Sciences et Techniques, 6 avenue Victor le Gorgeu, C.S. 93837, 29238 Brest, Cedex 3, France
| | - Gyula Tircsó
- Centre de Biophysique Moléculaire, CNRS, rue Charles Sadron, 45071 Orléans, Cedex 2, France
- Le Studium, Loire Valley Institute for Advanced Studies, 1 Rue Dupanloup, 45000 Orléans, France
| | | | | | | | - Andrés de Blas
- Grupo QUICOOR,
Centro de Investigaciones Científicas Avanzadas (CICA) and
Departamento de Química Fundamental, Universidade da Coruña, Campus
da Zapateira, Rúa da Fraga 10, 15008 A Coruña, Spain
| | - Teresa Rodríguez-Blas
- Grupo QUICOOR,
Centro de Investigaciones Científicas Avanzadas (CICA) and
Departamento de Química Fundamental, Universidade da Coruña, Campus
da Zapateira, Rúa da Fraga 10, 15008 A Coruña, Spain
| | - Carlos Platas-Iglesias
- Grupo QUICOOR,
Centro de Investigaciones Científicas Avanzadas (CICA) and
Departamento de Química Fundamental, Universidade da Coruña, Campus
da Zapateira, Rúa da Fraga 10, 15008 A Coruña, Spain
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10
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Maria L, Santos IC, Sousa VR, Marçalo J. Uranium(III) redox chemistry assisted by a hemilabile bis(phenolate) cyclam ligand: uranium-nitrogen multiple bond formation comprising a trans-{RN═U(VI)═NR}(2+) complex. Inorg Chem 2015; 54:9115-26. [PMID: 26355956 DOI: 10.1021/acs.inorgchem.5b01547] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A new monoiodide U(III) complex anchored on a hexadentate dianionic 1,4,8,11-tetraazacyclotetradecane-based bis(phenolate) ligand, [U(κ(6)-{((tBu2)ArO)2Me2-cyclam})I] (1), was synthesized from the reaction of [UI3(THF)4] (THF = tetrahydrofuran) and the respective potassium salt K2((tBu2)ArO)2Me2-cyclam and structurally characterized. Reactivity of 1 toward one-, two-, and four-electron oxidants was studied to explore the reductive chemistry of this new U(III) complex. Complex 1 reacts with one-electron oxidizers, such as iodine and TlBPh4, to form the seven-coordinate cationic uranium(IV) complexes [U(κ(6)-{((tBu2)ArO)2Me2-cyclam})I][X] (X = I (2-I), BPh4 (2-BPh4)). The new uranium(III) complex reacts with inorganic azides to yield the pseudohalide uranium(IV) complex [U(κ(6)-{((tBu2)ArO)2Me2-cyclam})(N3)2] (4) and the nitride-bridged diuranium(IV/IV) complex [(κ(4)-{((tBu2)ArO)2Me2-cyclam})(N3)U(μ-N)U(κ(5)-{((tBu2)ArO)2Me2-cyclam})] (5). Two equivalents of [U(κ(6)-{((tBu2)ArO)2Me2-cyclam})I] (1) effect the four-electron reduction of 1 equiv of PhN═NPh to form the bis(imido) complex [U(κ(4)-{((tBu2)ArO)2Me2-cyclam})(NPh)2] (6) and the U(IV) species 2-I. Moreover, the hemilability of the hexadentate ancillary ligand ((tBu2)ArO)2Me2-cyclam(2-) allows to perform the reductive cleavage of azobenzene with an unprecedented formation of a trans-bis(imido) complex. The complexes were characterized by NMR spectroscopy, and all the new uranium complexes were structurally authenticated by single-crystal X-ray diffraction.
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Affiliation(s)
- Leonor Maria
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa , Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal
| | - Isabel C Santos
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa , Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal
| | - Vânia R Sousa
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa , Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal
| | - Joaquim Marçalo
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa , Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal
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Alves LG, Souto M, Madeira F, Adão P, Munhá RF, Martins AM. Syntheses and solid state structures of cyclam-based copper and zinc compounds. J Organomet Chem 2014. [DOI: 10.1016/j.jorganchem.2013.11.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Barroso S, de Aguiar SR, Munhá RF, Martins AM. New zirconium complexes supported by N-heterocyclic carbene (NHC) ligands: Synthesis and assessment of hydroamination catalytic properties. J Organomet Chem 2014. [DOI: 10.1016/j.jorganchem.2013.11.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Carretas JM, Barroso S, Cui J, Cruz A, Santos IC, Martins AM. Diamine bis(phenolate) samarium complexes: Synthesis and structures. Inorganica Chim Acta 2013. [DOI: 10.1016/j.ica.2013.07.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Barroso S, Madeira F, Calhorda MJ, Ferreira MJ, Duarte MT, Martins AM. Toward the understanding of radical reactions: experimental and computational studies of titanium(III) diamine bis(phenolate) complexes. Inorg Chem 2013; 52:9427-39. [PMID: 23924047 DOI: 10.1021/ic401008y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Radical reactions of titanium(III) [Ti((tBu2)O2NN')Cl(S)] (S = THF, 1; S = py, 2; (tBu2)O2NN' = Me2N(CH2)2N(CH2-2-O-3,5-(t)Bu2C6H2)2) are described. Reactions with neutral electron acceptors led to metal oxidation to Ti(IV), [Ti((tBu2)O2NN')Cl(TEMPO)] (4) being formed with the TEMPO radical and [Ti((tBu2)O2NN')Cl2] (9) with PhN═NPh. [Ti((tBu2)O2NN')Cl2] was also formed when [Ti((tBu2)O2NN')Cl(S)] was oxidized by [Cp2Fe][BPh4], but the [Cp2Fe][PF6] analogue yielded [Ti((tBu2)O2NN')ClF] (8). The reactions of [Ti((tBu2)O2NN')Cl(S)] with O2 gave [Ti((tBu2)O2NN')Cl]2(μ-O) (3). The DFT calculated Gibbs energy for the above reaction showed it to be exergonic (ΔG298 = -123.6 kcal·mol(-1)). [Ti((tBu2)O2NN')(CH2Ph)(S)] (S = THF, 5; py, 6) are not stable in solution for long periods and in diethyl ether gave 1:1 cocrystals of [Ti((tBu2)O2NN')(CH2Ph)2] (7) and [Ti((tBu2)O2NN')Cl]2(μ-O) (3), most probably resulting from a disproportionation process of titanium(III) followed by oxygen abstraction by the resulting Ti(II) species. The oxidation of [Ti((tBu2)O2NN')(κ(2)-{CH2-2-(NMe2)-C6H4})] (10), which is a Ti(III) benzyl stabilized by the intramolecular coordination of the NMe2 moiety, led to a complex mixture. Recrystallization of this mixture under air led to a 1:1 cocrystal of two coordination isomers of the titanium oxo dimer (3). In one of these isomers, one metal is pentacoordinate and the dimethylamine moiety of the diamine bis(phenolate) ligand is not bonded to the metal, displaying a coordination mode of the ligand never observed before. The other titanium center is distorted octahedral with two cis-phenolate moieties. In the second unit, the coordination of the two ancillary ligands to the titanium centers reveals mutually cis-phenolate groups in one-half of the molecule and trans-coordinated in the other titanium center, keeping a distorted octahedral environment around each titanium.
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Affiliation(s)
- Sónia Barroso
- Centro de Química Estrutural, Instituto Superior Técnico, TU Lisbon, 1049-001 Lisboa, Portugal
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