23562-84-7Relevant academic research and scientific papers
Acetyl Acetone Covalent Triazine Framework: An Efficient Carbon Capture and Storage Material and a Highly Stable Heterogeneous Catalyst
Jena, Himanshu Sekhar,Krishnaraj, Chidharth,Wang, Guangbo,Leus, Karen,Schmidt, Johannes,Chaoui, Nicolas,Van Der Voort, Pascal
, (2018/06/11)
We present, for the first time, Covalent Triazine Frameworks functionalized with acetyl acetonate group (acac-CTFs). They are obtained from the polymerization of 4,4'-malonyldibenzonitrile under ionothermal conditions and exhibit BET surface areas up to 1626 m2/g. The materials show excellent CO2 uptake (3.30 mmol/g at 273 K and 1 bar), H2 storage capacity (1.53 wt% at 77 K and 1 bar) and a good CO2/N2 selectivity (up to 46 at 298 K). The enhanced CO2 uptake value and good selectivity are due to the presence of dual polar sites (N and O) throughout the material. In addition, acac-CTF was used to anchor VO(acac)2 as a heterogeneous catalyst. The V@acacCTF showed outstanding reactivity and reusability for the modified Mannich-type reaction with a higher turnover number than the homogeneous catalyst. The higher reactivity and reusability of the catalyst comes from the coordination of the vanadyl ions to the acetyl acetonate groups present in the material. The strong metalation is confirmed from Fourier Transform Infrared analysis, 13C MAS NMR spectral analysis and X-ray photoelectron spectroscopy measurement. Detailed characterization of the V@acac-CTF reveals that electron donation from O^O of the acetyl acetonate group to VO(acac)2, combined with the very high surface area of acac-CTF, is responsible for the stabilization of the catalyst. Overall, this contribution highlights the necessity of stable catalytic binding sites on heterogeneous supports to fabricate greener catalysts for sustainable chemistry.
Ruthenium-Catalyzed Aminomethylation and Methylation of Phenol Derivatives Utilizing Methanol as the C1 Source
Kim, Seoksun,Hong, Soon Hyeok
, p. 798 - 810 (2017/03/11)
A reaction involving ortho-aminomethylation of phenol was developed via ruthenium-catalyzed dehydrogenation of methanol, an environmentally benign C1 building block, without the use of reactive reagents. The reaction was successfully applied to a range of substrates. When naphthol was employed instead of phenol, only methylation was observed. On the basis of various mechanistic studies, we propose that formamide barely participates in the reaction, which mainly occurs through an iminium cation intermediate. The difference in the reactivities of phenol and naphthol is attributable to stronger basicity of naphtholate as a conjugate base owing to its lower aromaticity. Plausible reaction pathways were proposed for both reactions. (Figure presented.).
Cu(II)-Catalyzed ortho-Selective Aminomethylation of Phenols
Dai, Jin-Ling,Shao, Nan-Qi,Zhang, Jin,Jia, Run-Ping,Wang, Dong-Hui
supporting information, p. 12390 - 12393 (2017/09/23)
A Cu(II)-catalyzed ortho-selective functionalization of free phenols with trifluoroborates to afford Csp2-Csp3 coupling products under mild conditions has been developed. A variety of functional groups on the phenol and the potassium aminomethyltrifluoroborate substrates were found compatible, furnishing the corresponding products in moderate to excellent yields. A single-electron transfer radical coupling mechanism involving a six-membered transition state is proposed to rationalize the high levels of ortho-selectivity in the reaction. This protocol provides straightforward access to ortho-aminomethyl-substituted phenols, unnatural amino acids and other bioactive small molecules.
Charge separation in a covalently-linked phthalocyanine-oligo(p- phenylenevinylene)-C60 system. Influence of the solvent polarity
Cid, Juan-José,Kahnt, Axel,Vázquez, Purificación,Guldi, Dirk M.,Torres, Tomás
experimental part, p. 216 - 224 (2012/06/30)
A photo- and redoxactive system ZnPc-oPPV-C60 2, in which the photoexcited state electron donor - zinc phthalocyanine - and the ground state electron acceptor - C60 - are connected by a oligo(p- phenylenevinylene) (oPPV) spacer, has been synthesized in a multi-step synthesis by means of two consecutive Wadsworth-Horner-Emmons and a dipolar 1,3-cycloaddition reactions as key steps. The simpler system ZnPc-C60 1 has also been prepared as a reference model for photophysical studies. In this regards, the photophysical investigations by means of fluorescence, flash photolysis, and transient-absorption spectroscopy have manifested a clear dependence between charge transfer kinetics and spatial arrangement. In both systems, intramolecular charge separation evolves from the photoexcited ZnPc and yields the ZnPc?+/C60?- radical ion pairs. Interestingly, the ZnPc?+/C60 ?- radical ion pair lifetimes and quantum yields are strongly impacted by the solvent polarity and the distance. To this end, maximum radical ion pair lifetimes of 2900 and 5530 ps were found in anisol for 1 and 2, respectively.
Regioselective mannich reaction of phenols under high pressure using dichloromethane as C1 unit
Matsumoto, Kiyoshi,Joho, Kouta,Mimori, Seisuke,Iida, Hirokazu,Hamana, Hiroshi,Kakehi, Akikazu
scheme or table, p. 1061 - 1067 (2009/06/28)
Regioselectivity in Mannich reaction of 4-, 3-, and 2-substituted phenols with typical heterocyclic amines are investigated under reaction conditions developed by us. Phenol and 4-alkyl, and 4-chlorophenols in the title reaction predominantly gave the corresponding 2-(aminomethyl)phenols, while 4-methoxyphenol afforded, in addition to the mono(aminomethyl)phenols, a considerable amount of the bis adducts. Peculiarly enough, 3-methylphenol with amines afforded 3-methyl-4-(aminomethyl)phenols whereas 2-methylphenol produced 2-methyl-6-(aminomethyl)phenols.
Substituents on quinone methides strongly modulate formation and stability of their nucleophilic adducts
Weinert, Emily E.,Dondi, Ruggero,Colloredo-Melz, Stefano,Frankenfield, Kristen N.,Mitchell, Charles H.,Freccero, Mauro,Rokita, Steven E.
, p. 11940 - 11947 (2007/10/03)
Electronic perturbation of quinone methides (QM) greatly influences their stability and in turn alters the kinetics and product profile of QM reaction with deoxynucleosides. Consistent with the electron-deficient nature of this reactive intermediate, electron-donating substituents are stabilizing and electron-withdrawing substituents are destabilizing. For example, a dC N3-QM adduct is made stable over the course of observation (7 days) by the presence of an electron-withdrawing ester group that inhibits QM regeneration. Conversely, a related adduct with an electron-donating methyl group is very labile and regenerates its QM with a half-life of approximately 5 h. The generality of these effects is demonstrated with a series of alternative quinone methide precursors (QMP) containing a variety of substituents attached at different positions with respect to the exocyclic methylene. The rates of nucleophilic addition to substituted QMs measured by laser flash photolysis similarly span 5 orders of magnitude with electron-rich species reacting most slowly and electron-deficient species reacting most quickly. The reversibility of QM reaction can now be predictably adjusted for any desired application.
