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Enamullah M, Haque I, Resma AK, Woschko D, Janiak C. Schiff Base in Ketoamine Form and Rh(η 4-cod)-Schiff Base Complex with Z' = 2 Structure from Pairwise C-H···Metallochelate-π Contacts. Molecules 2022; 28:172. [PMID: 36615366 PMCID: PMC9821875 DOI: 10.3390/molecules28010172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 12/28/2022] Open
Abstract
Condensation of 2-hydroxybenzaldehyde (salicylaldehyde) or 2-hydroxy-1-naphthaldehyde with 2-ethylaniline yields the Schiff base compound of (E)-2-(((2-ethylphenyl)imino)methyl)phenol (HL1) or (E)-1-(((2-ethylphenyl)imino)methyl)naphthalen-2-ol (HL2), which in turn react with the dinuclear complex of [Rh(η4-cod)(µ-O2CCH3)]2 (cod = cycloocta-1,5-diene) to afford the mononuclear (η4-cod){(E)-2-(((2-ethylphenyl)imino)methyl)phenolato-κ2N,O}rhodium(I), [Rh(η4-cod)(L1)] (1) or (η4-cod){(E)-1-(((2-ethylphenyl)imino)methyl)naphthalen-2-olato-κ2N,O}rhodium(I), [Rh(η4-cod)(L2)] (2) (L1 or L2 = deprotonated Schiff base ligand). The X-ray structure determination revealed that the HL2 exists in the solid state not as the usual (imine)N···H-O(phenol) form (enolamine form) but as the zwitterionic (imine)N-H+···-O(phenol) form (ketoamine form). 1H NMR spectra for HL2 in different solvents demonstrated the existence of keto-enol tautomerism (i.e., keto ⇆ enol equilibrium) in solution. The structure for 1 and 2 showed that the deprotonated Schiff base ligand coordinates to the Rh(η4-cod)-fragment as a six-membered N^O-chelate around the rhodium atom with a close-to-square-planar geometry. Two symmetry-independent molecules (with Rh1 and Rh2) were found in the asymmetric unit in 1 in a structure with Z' = 2. The supramolecular packing in HL2 was organized by π-π and C-H···π contacts, while only two recognized C-H···π contacts were revealed in 1 and 2. Remarkably, there were reciprocal or pairwise C-H···π contacts between a pair of each of the symmetry-independent molecules in 1. This pairwise C-H contact to the Rh-N^O chelate (metalloaromatic) ring may be a reason for the two symmetry-independent molecules in 1. Differential scanning calorimetry (DSC) analyses revealed an irreversible phase transformation from the crystalline-solid to the isotropic-liquid phase and subsequently confirmed the thermal stability of the compounds. Absorption spectra in solution were explained by excited state properties from DFT/TD-DFT calculations.
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Affiliation(s)
- Mohammed Enamullah
- Department of Chemistry, Jahangirnagar University, Dhaka 1342, Bangladesh
| | - Imdadul Haque
- Department of Chemistry, Jahangirnagar University, Dhaka 1342, Bangladesh
| | - Amina Khan Resma
- Department of Chemistry, Jahangirnagar University, Dhaka 1342, Bangladesh
| | - Dennis Woschko
- Institut für Anorganische Chemie und Strukturchemie, Universität Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Christoph Janiak
- Institut für Anorganische Chemie und Strukturchemie, Universität Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
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Klauke K, Zaitsau DH, Bülow M, He L, Klopotowski M, Knedel TO, Barthel J, Held C, Verevkin SP, Janiak C. Thermodynamic properties of selenoether-functionalized ionic liquids and their use for the synthesis of zinc selenide nanoparticles. Dalton Trans 2018; 47:5083-5097. [PMID: 29561056 DOI: 10.1039/c8dt00233a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Three selenoether-functionalized ionic liquids (ILs) of N-[(phenylseleno)methylene]pyridinium (1), N-(methyl)- (2) and N-(butyl)-N'-[(phenylseleno)methylene]imidazolium (3) with bis(trifluoromethanesulfonyl)imide anions ([NTf2]) were prepared from pyridine, N-methylimidazole and N-butylimidazole with in situ obtained phenylselenomethyl chloride, followed by ion exchange to give the desired compounds. The crystal structures of the bromide and tetraphenylborate salts of the above cations (1-Br, 2-BPh4 and 3-BPh4) confirm the formation of the desired cations and indicate a multitude of different supramolecular interactions besides the dominating Coulomb interactions between the cations and anions. The vaporization enthalpies of the synthesized [NTf2]-containing ILs were determined by means of a quartz-crystal microbalance method (QCM) and their densities were measured with an oscillating U-tube. These thermodynamic data have been used to develop a method for assessment of miscibility of conventional solvents in the selenium-containing ILs by using Hildebrandt solubility parameters, as well as for modeling with the electrolyte perturbed-chain statistical associating fluid theory (ePC-SAFT) method. Furthermore, structure-property relations between selenoether-functionalized and similarly shaped corresponding aryl-substituted imidazolium- and pyridinium-based ILs were analyzed and showed that the contribution of the selenium moiety to the enthalpy of vaporization of an IL is equal to the contribution of a methylene (CH2) group. An incremental approach to predict vaporization enthalpies of ILs by a group contribution method has been developed. The reaction of these ILs with zinc acetate dihydrate under microwave irradiation led to ZnSe nanoparticles of an average diameter between 4 and 10 nm, depending on the reaction conditions.
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Affiliation(s)
- Karsten Klauke
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Dzmitry H Zaitsau
- Department of Physical Chemistry, Universität Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany.
| | - Mark Bülow
- Technische Universität Dortmund, Emil-Figge-Str. 70, 44227 Dortmund, Germany.
| | - Li He
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Maximilian Klopotowski
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Tim-Oliver Knedel
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Juri Barthel
- Gemeinschaftslabor für Elektronenmikroskopie RWTH-Aachen, Ernst-Ruska-Centrum für Mikroskopie und Spektroskopie mit Elektronen, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Christoph Held
- Technische Universität Dortmund, Emil-Figge-Str. 70, 44227 Dortmund, Germany.
| | - Sergey P Verevkin
- Department of Physical Chemistry, Universität Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany.
| | - Christoph Janiak
- Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
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Enamullah M, Chamayou AC, Banu KS, Kautz AC, Janiak C. Copper(II)-salicylaldehydate/-methoxy(pyridine-2-yl)methanolate complexes via in-situ hydrolysis of Schiff bases. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2017.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Enamullah M, Quddus MA, Rahman MM, Burrow TE. Syntheses, spectroscopy, cyclic voltammetry, thermal analyses, EPR, and DFT/TDDFT on bis[N-2-(R-pyridyl)salicylaldiminato-κ2NˆO]copper(II) (R = H, 4/6-CH3). J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Enamullah M, Islam MA, Joy BA, Reiss GJ. Bis[N-2-(R-pyridyl)-2-oxo-1-naphthaldiminato-κ2N^O]copper(II) (R = H, 4/6-CH3): Combined studies on syntheses, spectroscopy, cyclic voltammetry, thermal analyses, crystal structure and DFT/TDDFT. Inorganica Chim Acta 2016. [DOI: 10.1016/j.ica.2016.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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