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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 (BASEL, SWITZERLAND) 2022; 28:molecules28010172. [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] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 12/28/2022]
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
- Correspondence: (M.E.); (C.J.)
| | - 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
- Correspondence: (M.E.); (C.J.)
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Cao Q, Zhang S, Zhang L, Gao F, Chen J, Dong Y, Li X. Unprecedented Application of Covalent Organic Frameworks for Polymerization Catalysis: Rh/TPB-DMTP-COF in Polymerization of Phenylacetylene and Its Functional Derivatives. ACS APPLIED MATERIALS & INTERFACES 2021; 13:13693-13704. [PMID: 33709703 DOI: 10.1021/acsami.1c00512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Covalent organic frameworks (COFs) are applied widely in organic catalysis; however, no precedent has been reported in polymerization catalysis. Herein, we report the new application of COFs for polymerization catalysis. Different amounts of homogeneous Rh catalyst are incorporated into the COF via post-treatment to give a series of TPB-DMTP-COF-X wt % Rh (b-e) containing varying amounts of Rh from 2.74 to 11.38 wt %. In contrast to the known Rh catalysts, TPB-DMTP-COF-X wt % Rh (b-e) display an uncommon synergistic effect and exceptional steric confinement effect of nanochannels. Therefore, they possess the advantages of both homogeneous catalysts in high activity and selectivity and heterogeneous catalysts in stability and recyclability with extremely high activity up to 1.3 × 107 g·molRh-1·h-1 and cis-selectivity up to 99% and can be readily recycled and reused five times in the polymerization of phenylacetylene and its derivatives, affording cis-transoidal polyphenylacetylene and its derivatives having helical structures, aggregation-induced emission properties, or fluorescence properties with narrow molecular weight distributions.
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Affiliation(s)
- Qingbin Cao
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Shaowen Zhang
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Li Zhang
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Fei Gao
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Jupeng Chen
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Yuping Dong
- Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xiaofang Li
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
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Loong Tan NS, Nealon GL, Turner GF, Moggach SA, Ogden MI, Massi M, Lowe AB. Rh(I)(2,5-norbornadiene)(biphenyl)( tris(4-fluorophenyl)phosphine): Synthesis, Characterization, and Application as an Initiator in the Stereoregular (Co)Polymerization of Phenylacetylenes. ACS Macro Lett 2020; 9:56-60. [PMID: 35638650 DOI: 10.1021/acsmacrolett.9b00975] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis of the Rh(I)-aryl complex, Rh(I)(nbd)(BiPh)(P(4-FC6H4)3) is reported and its efficacy as an initiator for the (co)polymerization of phenylacetylenes established. The X-ray crystal structure indicates that the complex adopts a slightly distorted square planar geometry whose purity and structure was also confirmed by elemental analysis and 1H, 13C, 31P, 19F, 103Rh, and 31P-103Rh{1H} HMQC NMR spectroscopy. We demonstrate that Rh(I)(nbd)(BiPh)(P(4-FC6H4)3) mediates the (co)polymerization of phenylacetylenes in a controlled fashion with initiation efficiencies as high as 0.98, as evidenced by the pseudo-first-order kinetic and number-average molecular weight versus conversion profiles. The ability to form well-defined AB diblock copolymers, in a stereoregular manner, by sequential monomer addition is verified in the block copolymerization of phenylacetylene with 4-fluorophenylacetylene with quantitative crossover efficiency, as determined by size exclusion chromatography.
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Affiliation(s)
- Nicholas Sheng Loong Tan
- Curtin Institute for Functional Molecules and Interfaces (CIFMI) and School of Molecular and Life Sciences (MLS), Curtin University, Kent Street, Bentley, Perth, Western Australia 6102, Australia
| | - Gareth L. Nealon
- Centre for Microscopy, Characterisation, and Analysis (CMCA) and School of Molecular Sciences, M310, University of Western Australia, 35 Stirling Highway, Perth, Western Australia 6009, Australia
| | - Gemma F. Turner
- Centre for Microscopy, Characterisation, and Analysis (CMCA) and School of Molecular Sciences, M310, University of Western Australia, 35 Stirling Highway, Perth, Western Australia 6009, Australia
| | - Stephen A. Moggach
- Centre for Microscopy, Characterisation, and Analysis (CMCA) and School of Molecular Sciences, M310, University of Western Australia, 35 Stirling Highway, Perth, Western Australia 6009, Australia
| | - Mark I. Ogden
- Curtin Institute for Functional Molecules and Interfaces (CIFMI) and School of Molecular and Life Sciences (MLS), Curtin University, Kent Street, Bentley, Perth, Western Australia 6102, Australia
| | - Massimiliano Massi
- Curtin Institute for Functional Molecules and Interfaces (CIFMI) and School of Molecular and Life Sciences (MLS), Curtin University, Kent Street, Bentley, Perth, Western Australia 6102, Australia
| | - Andrew B. Lowe
- Curtin Institute for Functional Molecules and Interfaces (CIFMI) and School of Molecular and Life Sciences (MLS), Curtin University, Kent Street, Bentley, Perth, Western Australia 6102, Australia
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