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5. Theoretical Insight into the Multiple Roles of the Silyl-Phenanthroline Ligand in Ir-Catalyzed C(sp3)–H Borylation

Author

Bao, Lin-Yan, Wang, Jian-Sen, Li, Lu, Zhong, Rong-Lin, and Su, Zhong-Min

Abstract

Silyl-phenanthroline (NN′Si) ligand ancillary iridium-catalyzed C(sp3)–H borylation is investigated theoretically. Density functional theory calculations clearly disclose that the (NN′Si)IrV(H)(Bpin)3(NN′Si = 6-[(di-tert-butylsilyl)methyl]-1,10-phenanthroline) complex is a resting state, and the (NN′Si)IrIII(Bpin)2complex serves as an active species in the catalytic cycle. The remarkably high activity of this type of a catalyst arises from the rapid reductive elimination of HBpin from (NN′Si)IrV(H)(Bpin)3to generate the active species (NN′Si)IrIII(Bpin)2. The silyl group plays a crucial role in accelerating the crucial hydride-migration elementary step, which allows the isomerization of the (NN′Si)IrV(R)(H)(Bpin)2intermediate to achieve the C(sp3)–B reductive elimination and afford the borylated product. Although C(sp3)–H borylation with HBpin is thermodynamically unfavorable, the Ir-dihydride intermediate (NN′Si)IrV(H)2(Bpin)2generated after product formation is slightly more stable than resting-state (NN′Si)IrV(H)(Bpin)3in this catalytic cycle, which is an important driving force for the HBpin reaction. Such success was not attained by many other traditional bidentate ligands. The unique regioselectivity of n-butyl ethyl ether and 2-methylheptane, induced by the NN′Si-pincer ligand, is well reproduced and the underlying reason for the selectivity is clearly elucidated.

Published
2024
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11. The Difference in Ir-Catalyzed C(sp2)–H and C(sp3)–H Bond Activation Assisted by a Directing Group: Cyclometalation via Cis- or Trans-Chelation?

Author

Meng, Ling-Qi, Wang, Jian-Sen, You, Xiao-Xia, Zhong, Rong-Lin, Gao, Feng-Wei, and Su, Zhong-Min

Abstract

Iridium-catalyzed C–H borylation of aromatic and aliphatic hydrocarbons assisted by a directing group was theoretically investigated. Density functional theory (DFT) calculations revealed both Ir-catalyzed C(sp2)–H and C(sp3)–H borylations via an IrIII/IrVcatalytic cycle, where the tetra-coordinated (C, N)IrIII(Bpin)2complex with two vacant sites is an active species. Dramatically, the orientation of cyclometalation for C(sp2)–H bond activation assisted by a directing group is different from the C(sp3)–H one. The activation energy (ΔG°‡= 28.5 kcal mol–1) of the C(sp2)–H bond via trans-chelation to form cyclometalation is lower than that (41.4 kcal mol–1) via cis-chelation. In contrast, the ΔG°‡(26.6 kcal mol–1) of the C(sp3)–H bond via cis-chelation to form cyclometalation is lower than that (34.3 kcal mol–1) via trans-chelation. In addition, the rate-determining step of Ir-catalyzed C(sp2)–H borylation is oxidative addition of the C(sp2)–H bond, while that of C(sp3)–H analogues is hydride migration. Such differences arise from not only the differences in the steric hindrance of the C(sp2) and secondary C(sp3) atoms but also the differences in the trans effect and steric effect of the two vacant sites of active species. These findings were expected to facilitate further studies on the design and synthesis of innovative ligands for Ir-catalyzed C–H borylation.

Published
2024
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20. Design and Implementation of Solar OLED Lighting Driver Circuit with Frequency Modulation Control

Author

Zhong-Rong Lin and Huang-Jen Chiu

Subjects
SEPIC converter, zero voltage switching, triangular current mode, frequency modulation, maximum power point tracking, Technology
Abstract

This paper proposes a single-stage single-ended primary inductor converter (SEPIC) converter circuit, which is applied to the organic light-emitting diodes (OLED) driver circuit. The circuit proposed in this paper replaces the output Schottky diode from the original SEPIC with a power switch. Deadtime is added to prevent the on-state overlapping of two switches with zero voltage switching (ZVS), and the circuit operates in triangular current mode. The digital control methods are maximum power point tracking and frequency modulation using a battery to supply the converter and illuminate the OLED at night. Finally, a prototype is implemented to show the feasibility under the DC input voltage range of 10–40 V. The DC output is 12 V/1 A/12 W, and the conversion efficiency is up to 96.3%.

Published
2020
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26. An Iridium/Aluminum Cooperative Strategy for the β‐C(sp3)‐H Borylation of Saturated Cyclic Amines.

Author

Kuroda, Yusuke, Park, Kyungho, Shimazaki, Yuto, Zhong, Rong‐Lin, Sakaki, Shigeyoshi, and Nakao, Yoshiaki

Subjects
BORYLATION, IRIDIUM, ALUMINUM catalysts, ALUMINUM, LEWIS pairs (Chemistry), TRANSITION state theory (Chemistry)
Abstract

Despite the widespread success in the functionalization of C(sp2)−H bonds, the deliberate functionalization of C(sp3)−H bonds in a highly site‐ and stereoselective manner remains a longstanding challenge. Herein, we report an iridium/aluminum cooperative catalytic system that enables the β‐selective C−H borylation of saturated cyclic amines and lactams. Furthermore, we have accomplished an enantioselective variant using binaphthol‐derived chiral aluminum catalysts to forge C−B bonds with high levels of stereocontrol. Computational studies suggest that the formation of a Lewis pair with the substrates is crucial to lower the energy of the transition state for the rate‐determining reductive elimination step. [ABSTRACT FROM AUTHOR]

Published
2023
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34. Carbon Dioxide Electroreduction: Efficient Electron Transfer from Electron‐Sponge Polyoxometalate to Single‐Metal Site Metal–Organic Frameworks for Highly Selective Electroreduction of Carbon Dioxide (Small 20/2021)

Author

Sun, Ming‐Liang, primary, Wang, Yi‐Rong, additional, He, Wen‐Wen, additional, Zhong, Rong‐Lin, additional, Liu, Qing‐Zhi, additional, Xu, Shiyou, additional, Xu, Jing‐Mei, additional, Han, Xiao‐Long, additional, Ge, Xueying, additional, Li, Shun‐Li, additional, Lan, Ya‐Qian, additional, Al‐Enizi, Abdullah M., additional, Nafady, Ayman, additional, and Ma, Shengqian, additional

Published
2021
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35. Design and Implementation of Solar OLED Lighting Driver Circuit with Frequency Modulation Control

Author

Huang-Jen Chiu and Zhong-Rong Lin

Subjects
Control and Optimization, triangular current mode, Computer science, Energy Engineering and Power Technology, 02 engineering and technology, SEPIC converter, Driver circuit, Inductor, lcsh:Technology, Maximum power point tracking, 020210 optoelectronics & photonics, zero voltage switching, 0202 electrical engineering, electronic engineering, information engineering, Hardware_INTEGRATEDCIRCUITS, Digital control, Electrical and Electronic Engineering, Engineering (miscellaneous), Diode, lcsh:T, Renewable Energy, Sustainability and the Environment, business.industry, Electrical engineering, Battery (vacuum tube), Schottky diode, maximum power point tracking, frequency modulation, business, Frequency modulation, Energy (miscellaneous)
Abstract

This paper proposes a single-stage single-ended primary inductor converter (SEPIC) converter circuit, which is applied to the organic light-emitting diodes (OLED) driver circuit. The circuit proposed in this paper replaces the output Schottky diode from the original SEPIC with a power switch. Deadtime is added to prevent the on-state overlapping of two switches with zero voltage switching (ZVS), and the circuit operates in triangular current mode. The digital control methods are maximum power point tracking and frequency modulation using a battery to supply the converter and illuminate the OLED at night. Finally, a prototype is implemented to show the feasibility under the DC input voltage range of 10&ndash, 40 V. The DC output is 12 V/1 A/12 W, and the conversion efficiency is up to 96.3%.

Published
2020
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36. Efficient Electron Transfer from Electron‐Sponge Polyoxometalate to Single‐Metal Site Metal–Organic Frameworks for Highly Selective Electroreduction of Carbon Dioxide

Author

Sun, Ming‐Liang, primary, Wang, Yi‐Rong, additional, He, Wen‐Wen, additional, Zhong, Rong‐Lin, additional, Liu, Qing‐Zhi, additional, Xu, Shiyou, additional, Xu, Jing‐Mei, additional, Han, Xiao‐Long, additional, Ge, Xueying, additional, Li, Shun‐Li, additional, Lan, Ya‐Qian, additional, Al‐Enizi, Abdullah M., additional, Nafady, Ayman, additional, and Ma, Shengqian, additional

Published
2021
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41. A High voltage-gain boost converter with coupled-inductor

Author

Yao-Ching Hsieh, Jing-Yuan Lin, Zhong-Rong Lin, You-Cheng Lin, Huang-Jen Chiu, and Mohammd Mahmood Alam

Subjects
0209 industrial biotechnology, Materials science, business.industry, 020208 electrical & electronic engineering, General Engineering, Electrical engineering, Hardware_PERFORMANCEANDRELIABILITY, 02 engineering and technology, Inductor, 020901 industrial engineering & automation, Hardware_GENERAL, Boost converter, Hardware_INTEGRATEDCIRCUITS, 0202 electrical engineering, electronic engineering, information engineering, business, Energy (signal processing), Voltage
Abstract

This paper presents a novel high voltage-gain boost converter with coupled-inductors. The proposed converter consists of two pairs of coupled-inductors to collect energy in parallel and release ene...

Published
2018
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42. High-Efficiency Wireless Power Transfer System for Electric Vehicle Applications

Author

Hsin-Che Hsieh, Ming-Cheng Chen, Yao-Ching Hsieh, Yu-Chen Liu, Huang-Jen Chiu, and Zhong-Rong Lin

Subjects
Engineering, business.product_category, business.industry, 020209 energy, 020208 electrical & electronic engineering, Electrical engineering, 02 engineering and technology, Power factor, Inductance, Electric vehicle, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Wireless power transfer, Electrical and Electronic Engineering, business, Air gap (plumbing), Voltage
Abstract

In this brief, a high-efficiency wireless power transfer (WPT) system for electric vehicle charging application is studied and implemented. Series–series resonant topology with RF feedback design is adopted as the WPT dc–dc stage due to the advantages of circuit simplicity, easy analysis, and control. A 500-W laboratory prototype is built and tested to verify the feasibility of the proposed design. According to the experimental results, high wall-to-battery efficiency and unity power factor can be achieved over an air gap of 15 cm and maximum sliding distance of 10 cm under various power conditions and universal input voltage from 90VAC to 264VAC.

Published
2017
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45. Analysis and Design of a Novel High Step-Down DC-DC Converter for Battery Applications

Author

Nguyen Anh Dung, Jih-Sheng Lai, Yu-Chen Chang, Huang-Jen Chiu, Zhong-Rong Lin, and Yu-Chen Liu

Subjects
business.industry, Buck converter, Computer science, 020208 electrical & electronic engineering, 05 social sciences, Electrical engineering, Battery (vacuum tube), High voltage, 02 engineering and technology, Inductor, law.invention, Capacitor, Control theory, law, 0202 electrical engineering, electronic engineering, information engineering, 0501 psychology and cognitive sciences, business, Low voltage, 050107 human factors, Voltage
Abstract

In this paper, the low voltage stress of switches, high voltage gain DC-DC converter is proposed. The operating principle of the converter is similar to that of the conventional buck converter. Therefore, the proposed converter can be operated in the discontinuous conduction mode, continuous conduction mode, depending on the design. Moreover, the controller is also similar to that of the traditional buck converter, results in the simple controller. Furthermore, the voltage stress of every switch is reduced significantly compared with the conventional converter. Therefore, the use of the low voltage rating switches reduces the losses significantly. A 200W converter prototype is successfully built and tested to verify the feasibility of the proposed converter.

Published
2018
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48. Theoretical investigation on the 2e/12c bond and second hyperpolarizability of azaphenalenyl radical dimers: Strength and effect of dimerization.

Author

Zhong, Rong-Lin, Xu, Hong-Liang, Sun, Shi-Ling, Qiu, Yong-Qing, Zhao, Liang, and Su, Zhong-Min

Subjects
*PHYSICAL & theoretical chemistry research, *MOLECULAR polarizability, *PHENALENYL radicals, *AZA compounds, *DIMERS, *DIMERIZATION kinetics, *ELECTRON-deficient bonds
Abstract

An increasing number of chemists have focused on the investigations of two-electron/multicenter bond (2e/mc) that was first introduced to describe the structure of radical dimers. In this work, the dimerization of two isoelectronic radicals, triazaphenalenyl (TAP) and hexaazaphenalenyl (HAP) has been investigated in theory. Results show TAP2 is a stable dimer with stronger 2e/12c bond and larger interaction energy, while HAP2 is a less stable dimer with larger diradical character. Interestingly, the ultraviolet-visible absorption spectra suggest that the dimerization induces a longer wavelength absorption in visible area, which is dependent on the strength of dimerization. Significantly, the amplitude of second hyperpolarizability (γyyyy) of HAP2 is 1.36 × 106 a.u. that is larger than 7.79 × 104 a.u. of TAP2 because of the larger diradical character of HAP2. Therefore, the results indicate that the strength of radical dimerization can be effectively detected by comparing the magnitude of third order non-linear optical response, which is beneficial for further theoretical and experimental studies on the properties of complexes formed by radical dimerization. [ABSTRACT FROM AUTHOR]

Published
2013
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