Article
Multidisciplinary Sciences
Zhipeng Lu, Minsoo Ju, Yi Wang, Jonathan M. Meinhardt, Jesus I. Martinez Alvarado, Elisia Villemure, Jack A. Terrett, Song Lin
Summary: This study demonstrates the functionalization of C(sp(3))-H bonds using frustrated radical pairs (FRPs) generated from disilazide donors and an N-oxoammonium acceptor. The FRPs cleave unactivated C-H bonds to provide aminoxylated products, and the reaction selectivity towards tertiary, secondary, or primary C-H bonds can be controlled by tuning the structure of the donor. Mechanistic studies confirm the formation and involvement of radical pairs in the target reaction.
Review
Chemistry, Multidisciplinary
Minsoo Ju, Zhipeng Lu, Luiz F. T. Novaes, Jesus I. Martinez Alvarado, Song Lin
Summary: Frustrated radical pairs (FRPs) are able to coexist in solution due to steric repulsion or weak bonding association between two distinct radicals, which would otherwise annihilate each other. They are typically formed via spontaneous single-electron transfer between two sterically encumbered precursors and exhibit orthogonal chemical properties. FRPs have been found to be capable of homolytically activating various chemical bonds and are being extensively explored in synthetic organic chemistry, including C-H bond functionalization.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Chamila Manankandayalage, Daniel K. Unruh, Clemens Krempner
Summary: The intramolecular inverse frustrated Lewis pairs (FLPs) with weakly Lewis acidic boryl and strongly basic guanidino moieties were synthesized and characterized, demonstrating their capability to activate small molecules. These novel FLPs show promising potential in diverse chemical transformations.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Haishuai Cui, Xiaoqing Liao, Yufan Ren, Yang Zhou, Jing Xiao, Renjie Deng, Yang Lv, Huajie Liu, Pingle Liu, Hai Yang
Summary: In this article, a facile strategy is proposed to synthesize oxygen-defect-rich Co3O4@NC porous nanorods. These materials are proven to have FLPs sites. The oxygen-defect-rich Co3O4@NC exhibits high selectivity and catalytic performance towards cinnamaldehyde.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Meng Wang, Muralidharan Shanmugam, Eric J. L. McInnes, Michael P. Shaver
Summary: Polymeric frustrated radical pairs (poly(FRP)s) were synthesized by in situ photoinduction of FLP moieties, enabling single electron transfer (SET). The radical generation was confirmed by monitoring stable polymeric phosphine radical cations. These new poly(FRP)s exhibited catalytic hydrogenation and radical-mediated photocatalytic perfluoroalkylations, providing new avenues for designing novel functional polymers in catalysis and photoelectrical chemistry.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Inorganic & Nuclear
Pallavi Sarkar, Shubhajit Das, Swapan K. Pati
Summary: Research findings show that utilizing neutral tetrel atoms as acceptor sites in FLP can achieve the required Lewis acidity through antibonding orbitals, impacting the synchronicity of bond breaking and formation during H-2 activation. Varying the identity of the donor site can significantly affect the energetics of H-2 activation. Additionally, the study explores the potential extension of H-2 activation to catalytic hydrogenation by these FLPs.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Jorge Juan Cabrera-Trujillo, Israel Fernandez
Summary: This study computationally explored the activation of a single C-F bond in di- and trifluoromethyl groups by frustrated Lewis pairs (FLPs), revealing a unique cooperative action by the FLP partners. The process proceeds through the intermediacy of a rare hypervalent species featuring a pentacoordinate carbon atom.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Inorganic & Nuclear
Hannah J. J. Dokken, Brandon L. L. Frenette, Michael J. J. Ferguson, Eric Rivard
Summary: We report the synthesis and reactivity of a geminal-linked fluorene-derived frustrated Lewis pair (FLP), (Pr2P)-Pr-i(C13H8)BCy2 (1). Compound 1 displays anomalous behavior towards small molecules, acting as a masked FLP. This behavior is attributed to significant polarization of the B-C(fluorene) bond in 1, as determined by density functional theory (DFT) computations. We show the exploitation of this B-C bond polarity through reactions with PhPCl2, H3N center dot BH3, and (PrNH2)-Pr-i, leading to P-Cl and N-H bond activation, respectively.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Weining Zhang, Zhenhua Yang, Hailian Wang, Lei Lu, Depei Liu, Taozhu Li, Shicheng Yan, Hao Qin, Tao Yu, Zhigang Zou
Summary: Research shows that FLPs with shorter acid-base distance are more efficient in CO2 activation. The combination effects between facet junction separating charges and FLPs activating molecules can accelerate CO2 reduction.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Chemistry, Multidisciplinary
Dipendu Mandal, Ting Chen, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: In this work, we reported the reactions of phosphine/borane FLPs with chlorodiazirines, which resulted in the reduction of the N=N double bond and formation of phosphinimide/amidoborate zwitterions. A mechanistic study using DFT showed that these reactions proceed through FLP addition and subsequent group transfer reactions to nitrogen, followed by the capture of a halide anion.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
C. Li, A-D Manick, J-P Dutasta, X. Bugaut, B. Chatelet, A. Martinez
Summary: This study investigates the effects of the size and shape of molecular cavities on the frustrated behavior of Lewis/Bronsted acid-base pairs and on catalytic activities using different endohedrally functionalized cages. The results show that the shape of the inner space strongly influences these properties. A small change in the cage size can significantly affect the frustrated properties of the related systems, highlighting the importance of finding the right balance between frustrated behavior and cage flexibility for optimal catalytic applications.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Laura Koering, Arne Stepen, Bernhard Birenheide, Simon Barth, Maxim Leskov, Roland Schoch, Felix Kraemer, Frank Breher, Jan Paradies
Summary: A series of redox-responsive ferrocenyl-substituted boranes and boronic esters were synthesized, and the oxidation of the ferrocenyl ligand to the ferrocenium increased the Lewis acidity beyond the strength of SbF5. This was investigated experimentally and computationally, and the resulting highly Lewis acidic boron compounds were used for catalytic C-F and S-F bond activation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Nanoscience & Nanotechnology
Davide Salusso, Giorgio Grillo, Maela Manzoli, Matteo Signorile, Spyridon Zafeiratos, Mathias Barreau, Alessandro Damin, Valentina Crocella, Giancarlo Cravotto, Silvia Bordiga
Summary: Frustrated Lewis pairs (FLPs), discovered in recent decades in homogeneous catalysts and more recently in heterogeneous catalysts, have attracted attention for their potential in activating small molecules. However, the activation mechanism of stable molecules like CO2 by FLPs remains unclear. In this study, a spectroscopic investigation of a highly defective CeO2 sample prepared by microwave-assisted synthesis reveals the formation of FLPs. Carbon dioxide activation over the FLPs involves a bidentate carbonate bridging the FLP, with a Ce3+-to-CO2 charge transfer playing a role in enhancing its activation. The reaction of carbon dioxide with methanol to form monomethylcarbonate is used as evidence for the active roles of FLPs and a proposed reaction mechanism clarifies the roles of Ce3+ and oxygen vacancies.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Ayan Dasgupta, Katarina Stefkova, Rasool Babaahmadi, Brian F. Yates, Niklaas J. Buurma, Alireza Ariafard, Emma Richards, Rebecca L. Melen
Summary: The donor-acceptor ability of frustrated Lewis pairs has been widely used in organic synthesis. Single electron transfer can generate a frustrated radical pair, leading to different reaction pathways and selectivity depending on the substrate and energy required. Investigation using EPR studies, kinetic studies, and DFT calculations has helped elucidate the mechanism of these coupling reactions and explain solvent-dependent site selectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Review
Chemistry, Multidisciplinary
Xiangqing Feng, Wei Meng, Haifeng Du
Summary: This review provides an overview of the important progress made in FLP-catalyzed asymmetric reactions over the past 15 years. The design and synthesis of chiral FLPs, as well as their applications in hydrogenation, hydrosilylation, and transfer hydrogenation, are summarized and highlighted.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Dipendu Mandal, Zahid Hussain, Yong-an Luo, Yile Wu, Douglas W. W. Stephan
Summary: The reactions of boranes with azodicarboxylates or azodicarbonylamide provide easy access to NBO heterocyclic compounds. The formation mechanism is proposed to involve transient hydroboration or hydroalumination of the N=N double bond.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Jingjie Tan, Chaopeng Hu, Xin Yang, Shaoying Ju, Levy L. Cao, Yile Wu, Liu Leo Liu, Douglas W. Stephan
Summary: The aluminum analogue of Piers' borane, [HAl(C6F5)(2)](3)1, was prepared on a gram-scale. DFT calculations showed that 1 has a higher fluoride ion affinity (FIA) than Piers' borane, and the Al-H moiety proved to be a strong hydride donor, reacting with alcohol and terminal alkyne to give dehydrogenative products 3 and 4. Hydroalumination product 5 was obtained via the reaction of 1 with aldehyde. Additionally, 1 catalyzes the hydrosilylation of alkynes and alkenes.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Ting Chen, Yanbo Mei, Liu Leo Liu, Yufen Zhao, Yile Wu, Douglas W. Stephan
Summary: The combination of alkoxyphosphoranes and borane generates zwitterions that act as FLP and can alkylate nucleophiles to form C-C, C-N, C-H, and C-Cl coupling products. A DFT study reveals that the reaction proceeds through an FLP activation pathway, forming an alkoxyphosphonium intermediate that facilitates the alkylation of nucleophiles, similar to the Mitsunobu reaction.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Editorial Material
Chemistry, Multidisciplinary
Zahid Hussain, Yong-an Luo, Yile Wu, Zheng-wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: Interest in main group chemistry related to the Haber-Bosch process is less studied compared to transition metal species. In this study, steric demands in (tBuO(2)CN)(2) hinder the initial interaction of B(C6F5)(3) with nitrogen, leading to the loss of methylpropene and CO2 and the formation of diazene (N2H2) borane adduct 1 and the analogous hydrazine (N2H4) adduct 2. These species react with basic phosphines to form anions of 3 and 5, which contain N2H and N2H3 fragments and serve as metal-free models of plausible intermediates in N-2 reduction.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Hyehwang Kim, Zheng-wang Qu, Stefan Grimme, Nahil Al-Zuhaika, Douglas W. Stephan
Summary: The phosphino-phosphonium cations can react with alkynes through frustrated Lewis pair-type addition reactions, leading to phosphino-phosphination reactions. This reactivity can also be utilized to prepare dissymmetric cis-olefin-linked bidentate phosphines.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Inorganic & Nuclear
Ting Chen, Shaoying Ju, Mengnan Tong, Yufen Zhao, Yile Wu, Douglas W. Stephan
Summary: Metal phosphates are significant in the field of synthesis chemistry. In this study, we synthesized and characterized phosphate-catecholate chelated Nd(III), Zr(IV), and Al(III) chlorides (2-5). These complexes were obtained via ethyl chloride elimination reaction of oxophosphoranes with corresponding metal chlorides. The resulting monometallic and bimetallic phosphate-catecholate chelated metal complexes, stabilized by P-O and catecholate-O donors, have potential applications in catalysis.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Dipendu Mandal, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: Cyclopropenium cations with electron deficient substituents exhibit Lewis acidity despite the presence of π-electrons. The chloride and electron affinities are analyzed computationally and experimentally, respectively. These cations form traditional Lewis acid-base adducts with PPh3, while sterically hindered phosphines lead to frustrated Lewis pairs that participate in FLP additions. Depending on the basicity of the phosphine, addition to alkynes or alkyne deprotonation can occur. In both cases, new C-C bonds are formed, thus expanding the application of FLP chemistry to these delocalized π-cations.
CHEMICAL COMMUNICATIONS
(2023)
Review
Chemistry, Multidisciplinary
Douglas W. W. Stephan
Summary: Transition metal species readily capture and react with CO, while main group CO adducts and their subsequent reactivity have been less studied. This review focuses on the application of Frustrated Lewis Pairs (FLPs) to develop main group chemistry of CO, illustrating the ability to capture CO and subsequent reduction reactions. These developments suggest that FLPs provide an alternative strategy to enhance the reactivity of CO, promising future advances in homogeneous CO chemistry.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Zahid Hussain, Yong-An Luo, Yile Wu, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: The reactions of (tBuO(2)CN)(2) with FLPs were investigated. B(C6F5)(3) interacts with the carbonyl oxygen atoms and causes the loss of CH2=CMe2. However, in the presence of basic donors, the protons are intercepted and form salts [Hbase](2) [((C6F5)(3)BO2CN)(2)]. In the presence of (o-Tol)(3)P, a proton transfers to the diazo-N atom and forms (o-Tol)(3)PN(CO(2)tBu)NHB(C6F5)(3). Further addition of B(C6F5)(3) prompts the loss of olefin CH2=CMe2 and CO2, resulting in the formation of (o-Tol)(3)PNHNHB(C6F5)(3). DFT calculations provide insights into the reaction mechanisms and confirm the nature of 5 as a FLP reduction product of a diazene fragment.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Hyehwang Kim, Douglas W. Stephan
Summary: A combination of a phosphinidene precursor, B(C6F5)(3), and 4-ethynyltoluene produced the FLP addition product, Et2N(C14H10)PC(Tol)=CH(B(C6F5)(3))2. Compound 2 reacted with halides, pseudo halides, or Me3SiSPh, providing an easy method for synthesizing salts of anionic phosphines, while the reaction with PEt3 resulted in the zwitterionic species, Et3PCH=C(SiMe3)P(NEt2)C(Tol)=CHB(C6F5)(3)8. This latter species reacted with an alkyne, yielding a phosphine donor with both olefin linked cationic and anionic substituents.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Vaibhav Bedi, Dipendu Mandal, Zahid Hussain, Shi-Ming Chen, Yile Wu, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: The reaction of (tBuO(2)CN)(2) with 9-BBN leads to the formation of a bicyclic heterocyclic compound, while its reactions with BF3 or [Et3Si][B(C6F5)(4)] result in the isolation of different compounds. Computational studies reveal that the steric and electronic properties of the Lewis acid are important in the formation of one of the compounds.
DALTON TRANSACTIONS
(2024)
Article
Chemistry, Organic
Jiangkun Xiong, Maying Yan, Lvnan Jin, Weihong Song, Lei Xiao, Dong Xu, Chunyang Zhai, Douglas W. Stephan, Jing Guo
Summary: In this study, a new reaction method was reported for the synthesis of various organogermacycle compounds via a B(C6F5)(3) mediated domino hydrogermylation reaction of enones with dihydrogermanes. These germacyclic compounds were obtained in good to excellent yields under mild reaction conditions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Ryan J. Andrews, John R. De Backere, Douglas W. Stephan
Summary: In this study, stable thionylium dications were synthesized with high acidity comparable to BF3 and PF5. These compounds can activate C-F bonds of fluoroalkanes and effectively deoxygenate O2- through reactions with Ph3PO and CuO.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Linkun Miao, Amir Yeganeh-Salman, Jason Yeung, Douglas W. Stephan
Summary: Efforts were made to deprotonate halophosphonium cations and generate various derivatives. It was found that one derivative is particularly effective in synthesizing methylene phosphonium cations. Additionally, differences in reactions with different types of olefins were observed, enhancing the synthetic methods for related compounds.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Organic
Lvnan Jin, Xuan Zhou, Yunbo Zhao, Jing Guo, Douglas W. Stephan
Summary: This paper successfully achieves chemoselective insertions of diazoalkanes into 2-hydroxybenzothiazoles at different bond positions, resulting in the synthesis of multiple benzothiazole derivatives. These methods are scalable and demonstrate the complementary nature of different catalysts.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
