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Amiri Rudbari H, Saadati A, Ariaeefar M, Blacque O, Correia I, Islam MK, Woschko D, Janiak C, Enamullah M. Pseudotetrahedral Zn(II)-(R or S)-dihalogen-salicylaldiminato complexes with Λ- or Δ-chirality induction at-metal. Dalton Trans 2022; 51:2385-2399. [DOI: 10.1039/d1dt04220c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactions of enantiopure (S or R)-N-1-(phenyl)ethyl-2,4-X1,X2-salicylaldimine (S-H or R-H; X1, X2 = dihalogen) with Zn(II)-nitrate give bis[(S or R)-N-1-(phenyl)ethyl-2,4-X1,X2-salicylaldiminato-κ2N,O]-zinc(II), (Δ-ZnS or Λ-ZnR) with Δ/Λ-chirality induction at-metal in the C2-symmetric molecules....
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2
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Górecki M, Enamullah M, Islam MA, Islam MK, Höfert SP, Woschko D, Janiak C, Pescitelli G. Synthesis and Characterization of Bis[( R or S)- N-1-(X-C 6H 4)ethyl-2-oxo-1-naphthaldiminato-κ 2N, O]-Λ/Δ-cobalt(II) (X = H, p-CH 3O, p-Br) with Symmetry- and Distance-Dependent Vibrational Circular Dichroism Enhancement and Sign Inversion. Inorg Chem 2021; 60:14116-14131. [PMID: 34477372 PMCID: PMC8456410 DOI: 10.1021/acs.inorgchem.1c01503] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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The enantiopure Schiff
bases (R or S)-N-1-(X-C6H4)ethyl-2-hydroxy-1-naphthaldimine
{X = H [(R or S)-HL1], p-CH3O [(R or S)-HL2],
and p-Br [(R- or S)-HL3]} react with cobalt(II) acetate to give bis[(R or S)-N-1-(X-C6H4)ethyl-2-oxo-1-naphthaldiminato-κ2N,O]-Λ/Δ-cobalt(II) {X = H
[Λ/Δ-Co-(R or S)-L1], p-CH3O [Λ/Δ-Co-(R or S)-L2], and p-Br [Λ/Δ-Co-(R or S)-L3]} (1–3), respectively. Induced Λ and Δ chirality originates
at the metal center of the C2-symmetric
molecule in pseudotetrahedral geometry. Differential scanning calorimetry
analyses explored the thermal stability of the complexes, which undergo
reversible phase transformation from crystalline solid to isotropic
liquid phase for 1 and 3 but irreversible
phase transformation for 2. Like other cobalt(II) complexes,
compounds 1–3 exhibit a continuous
ensemble of absorption and circular dichroism bands, which span from
the UV to IR region and can be collected into a superspectrum. Infrared
vibrational circular dichroism (IR-VCD) spectra witness the coupling
between Co2+-centered low-lying electronic states and ligand-centered
vibrations. The coupling produces enhanced and almost monosignate
VCD spectra, with both effects being mode-dependent in terms of the A or B symmetry (in the C2 point group) and distance from the Co2+ core. Chiroptical superspectra of naphthaldiminatocobalt(II)
complexes 1−3 exhibit a continuous
ensemble of absorption
and circular dichroism bands from the UV to IR region, including peculiar
and almost monosignate vibrational circular dichroism (VCD) spectra
dominated by the coupling between Co2+-centered low-lying
electronic states and ligand-centered vibrations, which depend on
the normal-mode symmetry and distance from the Co2+ core
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Affiliation(s)
- Marcin Górecki
- Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa 56126, Italy.,Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw 01-224, Poland
| | - Mohammed Enamullah
- Department of Chemistry, Jahangirnagar University, Dhaka 1342, Bangladesh
| | | | | | - Simon-Patrick Höfert
- Institute of Inorganic Chemistry and Structural Chemistry, Heinrich-Heine-University of Düsseldorf, Düsseldorf 40225, Germany
| | - Dennis Woschko
- Institute of Inorganic Chemistry and Structural Chemistry, Heinrich-Heine-University of Düsseldorf, Düsseldorf 40225, Germany
| | - Christoph Janiak
- Institute of Inorganic Chemistry and Structural Chemistry, Heinrich-Heine-University of Düsseldorf, Düsseldorf 40225, Germany
| | - Gennaro Pescitelli
- Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa 56126, Italy
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3
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Enamullah M, Al-moktadir Zaman M, Bindu MM, Woschko D, Islam MK, Janiak C. Pseudotetrahedral high-spin manganese(II)-complexes with (S or R)-N-1-(Ar)ethyl-salicylaldimine: Chiroptical property, chirality induction at-metal, paramagnetism, redox-potential, PXRD structures and DFT/TDDFT. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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4
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Aryaeifar M, Amiri Rudbari H, Blacque O, Islam MK, Scopelliti R, Braun JD, Herbert DE, Bruno G, Janiak C, Enamullah M. Schiff base ligands derived from 1,2-bis(2′-nitro-/amino-phenoxy)-3-R-benzene and 2-hydroxy-1-naphthaldehyde and their Cu/Zn( ii) complexes: synthesis, characterization, X-ray structures and computational studies. CrystEngComm 2021. [DOI: 10.1039/d1ce00829c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Racemic crystals of Cu/Zn(ii)-tetradentate Schiff base ligands with Λ/Δ-chirality induction at-metal center.
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Affiliation(s)
- Mahnaz Aryaeifar
- Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran
| | - Hadi Amiri Rudbari
- Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran
| | - Olivier Blacque
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | | | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jason D. Braun
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - David E. Herbert
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Giuseppe Bruno
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno D'Alcontres 31, I-98166 Messina, Italy
| | - Christoph Janiak
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, D-40204 Düsseldorf, Germany
| | - Mohammed Enamullah
- Department of Chemistry, Jahangirnagar University, Dhaka 1342, Bangladesh
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5
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Enamullah M, Anwar Hossain M, Islam MK, Woschko D, Janiak C. Pseudotetrahedral copper(II)-complexes with enantiopure ( R or S)-2-(((aryl)ethylimino)ethyl)phenolate Schiff base ligands. Dalton Trans 2021; 50:9236-9249. [PMID: 34128030 DOI: 10.1039/d1dt01671g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Condensation of 2-hydroxy-benzophenone (HL') with (R or S)-(Ar)ethylamine yields the enantiopure Schiff bases (S or R)-2-((E)-1-(1-(Ar)ethylimino)ethyl)phenol {Ar = C6H5 (S- or R-HL1), p-CH3OC6H4 (S- or R-HL2)}. These Schiff bases react with copper(ii) acetate under reflux to give green microcrystals of bis[(R or S)-2-((E)-1-(1-(Ar)ethylimino)ethyl)phenolato-κ2N,O]-Λ/Δ-copper(ii), {Ar = C6H5 (Λ/Δ-Cu-R- or S-L1), p-CH3OC6H4 (Λ/Δ-Cu-R- or S-L2)} with induction of Λ/Δ-chirality at-metal. The presence of Schiff base ligands in the paramagnetic green microcrystals is confirmed by decomplexation reaction with NaCN via reduction of Cu(ii) to Cu(i) in DMSO-d6 solution. Crystallization attempts of the green microcrystalline Schiff-base Cu complexes provide deep-green block-shaped crystals of an about equal admixture of bis[2-oxo-benzophenonato-κ2O,O']-copper(ii), (CuL'2) and bis[2-(imino(phenyl)methyl)phenolato-κ2N,O]copper(ii), (CuL''2) via in situ hydrolysis of the coordinated Schiff base ligands back to 2-hydroxy-benzophenone (HL') and to 2-(imino(phenyl)methyl)phenol (HL''), which in-turn bind with the copper(ii) ion. Powder X-ray diffraction (PXRD) patterns of R-HL1 and Cu-R-L1 allowed their structure determinations using the program Expo-2014 followed by Rietveld refinement. The Cu structures refined to four-coordinated Λ/Δ-copper(ii)-complexes by the two phenolate-oxygen and two imine-nitrogen atoms from two Schiff base ligands in a pseudotetrahedral geometry. DFT optimized structures (at gas-phase) reveal the Δ-Cu-S-L1 or Λ-Cu-R-L1 diastereomer as slightly more stable than the corresponding Λ-Cu-S-L1 or Δ-Cu-R-L1 by ca. 7.60 kcal mol-1, resulting from diastereoselectively induced Λ vs. Δ-chirality at-metal. Electronic circular dichroism (ECD) spectra display mirror-image relationships and comparisons of experimental and simulated ECD spectra by TDDFT suggest an excess of the Δ-Cu-S-L1 or Λ-Cu-R-L1 diastereomer in solution. The cyclic voltammograms demonstrate two one electron charge transfer processes for Cu2+/Cu+ and Cu+/Cu0 couples in acetonitrile, respectively.
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Affiliation(s)
- Mohammed Enamullah
- Department of Chemistry, Jahangirnagar University, Dhaka-1342, Bangladesh.
| | | | | | - Dennis Woschko
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität, Universitätsstr. 1, D-40225 Düsseldorf, Germany.
| | - Christoph Janiak
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität, Universitätsstr. 1, D-40225 Düsseldorf, Germany.
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Mandal A, Nath B, Patel BK. Unraveling the role of non-covalent interactions to determine chiral selectivity in coordination compounds of racemic 1,2-dihydroquinazolinone ligands. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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7
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Kordestani N, Amiri Rudbari H, Bruno G, Rosario S, Braun JD, Herbert DE, Blacque O, Correia I, Zaman MAM, Bindu MM, Janiak C, Enamullah M. Solid-state to solution helicity inversion of pseudotetrahedral chiral copper(ii) complexes with 2,4-dihalo-salicylaldiminate ligands. Dalton Trans 2020; 49:8247-8264. [DOI: 10.1039/d0dt01649g] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Steric constraints by the halogen substituents show an efficient control of stereochemical behaviours of the complexes.
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Affiliation(s)
| | | | - Giuseppe Bruno
- Department of Chemical
- Biological
- Pharmaceutical and Environmental Sciences
- University of Messina
- I-98166 Messina
| | - Scopelliti Rosario
- Institut des Sciences et Ingénierie Chimiques
- École Polytechnique Fédérale de Lausanne (EPFL)
- CH-1015 Lausanne
- Switzerland
| | - Jason D. Braun
- Department of Chemistry
- University of Manitoba
- Winnipeg
- Canada
| | | | - Olivier Blacque
- Department of Chemistry
- University of Zurich
- Zurich
- Switzerland
| | - Isabel Correia
- Centro de Química Estrutural
- Departamento de Engenharia Química
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
| | | | | | - Christoph Janiak
- Institut für Anorganische Chemie und Strukturchemie
- Universität Düsseldorf
- D-40204 Düsseldorf
- Germany
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Dumitru F, van der Lee A, Barboiu M. Chiral superstructures from homochiral Zn 2+ , Co 2+ , Fe 2+ -2,6-bis (aryl ethylimine)pyridine complexes. Chirality 2019; 31:763-775. [PMID: 31392782 DOI: 10.1002/chir.23115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/15/2019] [Accepted: 07/06/2019] [Indexed: 11/07/2022]
Abstract
We report the hierarchical supramolecular organization of metallosupramolecular homochiral complexes 1-Λ-(S,S,S,S)-M2+ /1-∆-(R,R,R,R)-M2+ and 2- Λ-(S,S,S,S)-M2+ /2-∆- (R,R,R,R)-M2+ of M2+ = Co2+ , Fe2+ , Zn2+ metal ions with chiral pseudo-terpyridine-type ligands: 1-(S,S) or 1-(R,R) = 2,6-bis (naphthyl ethylimine)pyridine and 2-(S,S) or 2-(R,R) = 2,6-bis (phenyl-ethylimine)pyridine. Circular dichroism measurements in solution were used to confirm the enantiomeric nature of all twelve complexes. For crystal structures of 1- Λ- (S,S,S,S)-M2+ or 1-∆- (R,R,R,R)-M2+ complexes, absolute configurations {∆ (or P), Λ (or M)} were confirmed by refinement of the Flack parameter x: -0.007 ≤ x ≤ 0.11 for the single crystals of 1-Λ-(S,S,S,S)-M2+ /1-∆- (R,R,R,R)-M2+ , 2- Λ- (S,S,S,S)-Fe2+ , and 2-∆- (R,R,R,R)-Co2+ .
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Affiliation(s)
- Florina Dumitru
- Institut Européen des Membranes, UMR-CNRS 5635, Université Montpellier, ENSCM Place eugene Bataillon CC047, Montpellier, France.,Faculty of Applied Chemistry and Materials Science, Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, University Politehnica of Bucharest, Bucharest, Romania
| | - Arie van der Lee
- Institut Européen des Membranes, UMR-CNRS 5635, Université Montpellier, ENSCM Place eugene Bataillon CC047, Montpellier, France
| | - Mihail Barboiu
- Institut Européen des Membranes, UMR-CNRS 5635, Université Montpellier, ENSCM Place eugene Bataillon CC047, Montpellier, France
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9
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Supramolecular features of 2-(chlorophenyl)-3-[(chlorobenzylidene)-amino]-2,3-dihydroquinazolin-4(1 H )-ones: A combined experimental and computational study. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2017.10.085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Enamullah M, Quddus MA, Hasan MR, Pescitelli G, Berardozzi R, Makhloufi G, Vasylyeva V, Janiak C. Chirality at metal and helical ligand folding in optical isomers of chiral bis(naphthaldiminato)nickel(ii) complexes. Dalton Trans 2016; 45:667-80. [DOI: 10.1039/c5dt03940a] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ni-Schiff base complexes combine ligand chirality, chirality at metal, and helical ligand folding in a concerted way.
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Affiliation(s)
| | | | | | | | | | - Gamall Makhloufi
- Institut für Anorganische Chemie und Strukturchemie
- Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Vera Vasylyeva
- Institut für Anorganische Chemie und Strukturchemie
- Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Christoph Janiak
- Institut für Anorganische Chemie und Strukturchemie
- Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
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Enamullah M, Quddus MA, Hasan MR, Pescitelli G, Berardozzi R, Reiß GJ, Janiak C. Syntheses, Spectroscopy, and Structural Analyses of Dinuclear Chiral-at-Metal μ-Aqua-tetrakis[(RorS)-N-1-(Ar)ethylsalicylaldiminato]di-Λ- or -Δ-nickel(II) Complexes. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500128] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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12
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Qian SS, You ZL, Zhu HL. Crystal structure of an end-on azido-bridged polymeric zinc(II) complex. J STRUCT CHEM+ 2015. [DOI: 10.1134/s0022476615020274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Chamayou AC, Makhloufi G, Nafie LA, Janiak C, Lüdeke S. Solvation-Induced Helicity Inversion of Pseudotetrahedral Chiral Copper(II) Complexes. Inorg Chem 2015; 54:2193-203. [DOI: 10.1021/ic502661u] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Anne-Christine Chamayou
- Institut für Pharmazeutische Wissenschaften, Universität Freiburg, Albertstr. 25, D-79104 Freiburg, Germany
| | - Gamall Makhloufi
- Institut für
Anorganische Chemie und Strukturchemie, Universität Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Laurence A. Nafie
- Department of Chemistry, Syracuse University, Syracuse, New York 13244-4100, United States
| | - Christoph Janiak
- Institut für
Anorganische Chemie und Strukturchemie, Universität Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Steffen Lüdeke
- Institut für Pharmazeutische Wissenschaften, Universität Freiburg, Albertstr. 25, D-79104 Freiburg, Germany
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14
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Jena HS. Effect of steric congestion and non-covalent interaction on the self-organization of two isostructural 1D chiral coordination polymers. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.05.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Heider S, Petzold H, Speck JM, Rüffer T, Schaarschmidt D. Modification of a Hexadentate Amine based Ligand System byN-Methylation and Effects on Spin State and Redox Behavior of the Corresponding Transition Metal Complexes. Z Anorg Allg Chem 2014. [DOI: 10.1002/zaac.201300615] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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17
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Jena HS. Effect of cooperative non-covalent interactions on the solid state heterochiral self-assembly: The concepts of isotactic and syndiotactic arrangements in coordination complex. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2013.10.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Jena HS. Diastereoselective self-assembly of heterochiral Zn(ii) complexes of racemic Schiff bases in a chiral self-discriminating process: effect of non-covalent interactions on solid state structural self-assembly. RSC Adv 2014. [DOI: 10.1039/c3ra45082a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Jena HS. Effect of non-covalent interaction on the diastereoselective self-assembly of Cu(ii) complexes containing a racemic Schiff base in a chiral self-discriminating process. NEW J CHEM 2014. [DOI: 10.1039/c3nj01547e] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The effects of π⋯π interactions between benzene–pyridine rings on the diastereoselective self-assembly of Cu(ii) compounds in the chiral self-discrimination process are studied.
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Affiliation(s)
- Himanshu Sekhar Jena
- Department of Chemistry
- Indian Institute of Technology Guwahati
- Guwahati, India 781039
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Di Salvo F, Tsang MY, Teixidor F, Viñas C, Planas JG, Crassous J, Vanthuyne N, Aliaga-Alcalde N, Ruiz E, Coquerel G, Clevers S, Dupray V, Choquesillo-Lazarte D, Light ME, Hursthouse MB. A Racemic and Enantiopure Unsymmetric Diiron(III) Complex with a Chiralo-Carborane-Based Pyridylalcohol Ligand: Combined Chiroptical, Magnetic, and Nonlinear Optical Properties. Chemistry 2013; 20:1081-90. [DOI: 10.1002/chem.201303037] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Indexed: 11/06/2022]
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Enamullah M, Vasylyeva V, Janiak C. Chirality and diastereoselection of Δ/Λ-configured tetrahedral zinc(II) complexes with enantiopure or racemic Schiff base ligands. Inorganica Chim Acta 2013. [DOI: 10.1016/j.ica.2013.08.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Chamayou AC, Lüdeke S, Brecht V, Freedman TB, Nafie LA, Janiak C. Chirality and diastereoselection of Δ/Λ-configured tetrahedral zinc complexes through enantiopure Schiff base complexes: combined vibrational circular dichroism, density functional theory, 1H NMR, and X-ray structural studies. Inorg Chem 2011; 50:11363-74. [PMID: 22017347 DOI: 10.1021/ic2009557] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The metal-centered Δ/Λ-chirality of four-coordinated, nonplanar Zn(A(^)B)(2) complexes is correlated to the chirality of the bidentate enantiopure (R)-A(^)B or (S)-A(^)B Schiff base building blocks [A(^)B = (R)- or (S)-N-(1-(4-X-phenyl)ethyl)salicylaldiminato-κ(2)N,O with X = OCH(3), Cl, Br]. In the solid-state the (R) ligand chirality induces a Λ-M configuration and the (S) ligand chirality quantitatively gives the Δ-M configuration upon crystallization as deduced from X-ray single crystal studies. The diastereoselections of the pseudotetrahedral zinc-Schiff base complexes in CDCl(3) solution were investigated by (1)H NMR and by vibrational circular dichroism (VCD) spectroscopy. The appearance of two signals for the Schiff-base -CH═N- imine proton in (1)H NMR indicates an equilibrium of both Δ- and Λ-diastereomers with a diastereomeric ratio of roughly 20:80% for all three ligands. VCD proved to be very sensitive to the metal-centered Δ/Λ-chirality because of a characteristic band representing coupled vibrations of the two ligand's C═N stretch modes. The absolute configuration was assigned on the basis of agreement in sign with theoretical VCD spectra from Density Functional Theory calculations.
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Affiliation(s)
- Anne-Christine Chamayou
- Institut für Anorganische und Analytische Chemie, Universität Freiburg, Albertstrasse 21, D-79104 Freiburg, Germany
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Affiliation(s)
- Eric Meggers
- Fachbereich Chemie, Philipps‐Universität Marburg, Hans‐Meerwein‐Straße, 35043 Marburg, Germany
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N,N′-Bis(2,2′-bipyridine-6-ylmethyl)-2,2′-biphenylenediamines: A Tuneable Ligand Scaffold for Room Temperature Fe2+ SCO Complexes. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201001139] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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