Bimolecular Reaction Research Articles

Synthesis of Degradable Mainchain Semifluorinated Polyester by CuAAC with Reaction-Enhanced Reactivity of Intermediate (RERI) Mechanism.

Quantitative insertion of functionality into polymer chains via step-growth polymerization is challenging due to the random bimolecular reaction and relatively low extent of reaction. Herein, a copper-catalyzed azide-alkyne cycloaddition (CuAAC) step-growth polymerization with reaction-enhanced reactivity of intermediates (RERI) mechanism is applied for the precise insertion of degradable functions into the mainchain semifluorinated polymer and endowed it with controlled degradability. In this CuAAC polymerization, bis-alkynyl-terminated (A2) monomer can be quantitatively consumed when the slightly excess of 2,2-bis(azidomethyl)propane-1,3-diyl bis(2-methylpropanoate) (BiAz, B2) monomer with RERI effect is employed. The CuAAC copolymerization of o-nitrobenzyl ester-derived A2 (A2-ONB), fluorinated A2 (A2-F), and B2 monomers produced the mainchain semifluorinated copolymers with tunable chemical composition and high molecular weight, along with the random and quantitative insertion of [A2-ONB] units. These mainchain semifluorinated copolymers are capable of controlled degradation profile under ultraviolet radiation and can undergo complete degradation under basic condition. This work provided a simple approach for preparing mainchain semifluorinated polymers with controlled degradability.

Pyrolysis Kinetics of Polytetrafluoroethylene (PTFE)

ABSTRACTPolytetrafluoroethylene (PTFE) is widely used in fields such as propellants and flame retardants. However, this is still a vacancy of detailed kinetic mechanisms to describe the complete decomposition of PTFE in the gas phase. The current work addresses this issue by conducting ab initio calculations for key reactions involved in the PTFE pyrolysis system. The potential energy surfaces (PESs) of PTFE unimolecular and bimolecular reactions are determined at the DLPNO‐CCSD(T)/cc‐pVTZ//B3LYP‐D3/6–31++G(d,p) level. Rate constants and branching ratios of the main reaction pathways are calculated by solving the RRKM master equation, and the thermochemical properties of related species at the DLPNO‐CCSD(T)/CBS level are calculated via the atomization method. The current study found that the initial decomposition of PTFE is dominated by the CC scission reactions and free radical (H, OH, CF, CF2, and CF3) abstraction reactions, forming the corresponding free radical species. Further β‐CC scission reactions dominate the overall kinetics and continuously generate CF2CF2. Self‐decomposition and free radical–driven decomposition of PTFE produce small molecules such as HF, FOH, CF2, CF3, and CF4. This work provides quantitative predictions of the detailed decomposition reaction pathways of gas‐phase PTFE and will lay a solid foundation for the development of detailed kinetic mechanisms for PTFE combustion and degradation.

Influence of chemo‐hydrodynamical oscillations in bimolecular reactions on mixing

Influence of chemo‐hydrodynamical oscillations in bimolecular reactions on mixing

Chemical Reaction Networks from Scratch with Reaction Prediction and Kinetics-Guided Exploration.

Algorithmic reaction explorations based on transition state searches can now routinely predict relatively short reaction sequences involving small molecules. However, applying these algorithms to deeper chemical reaction network (CRN) exploration still requires the development of more efficient and accurate exploration policies. Here, an exploration algorithm, which we name yet another kinetic strategy (YAKS), is demonstrated that uses microkinetic simulations of the nascent network to achieve cost-effective, deep network exploration. Key features of the algorithm are the automatic incorporation of bimolecular reactions between network intermediates, compatibility with short-lived but kinetically important species, and incorporation of rate uncertainty into the exploration policy. In validation case studies of glucose pyrolysis, the algorithm rediscovers reaction pathways previously discovered by heuristic exploration policies and elucidates new reaction pathways for experimentally obtained products. The resulting CRN is the first to connect all major experimental pyrolysis products to glucose. Additional case studies are presented that investigate the role of reaction rules, rate uncertainty, and bimolecular reactions. These case studies show that naïve exponential growth estimates can vastly overestimate the actual number of kinetically relevant pathways in the physical reaction networks. In light of this, further improvements in exploration policies and reaction prediction algorithms make it feasible that CRNs might soon be routinely predictable in some contexts.

SN2-Reaction-Driven Bonding-Heterointerface Strengthens Buried Adhesion and Orientation for Advanced Perovskite Solar Cells.

Traditionally weak buried interaction without customized chemical bonding always goes against the formation of high-quality perovskite film that highly determines the efficiency and stability of perovskite solar cells. To address this issue, herein, we propose a bimolecular nucleophilic substitution reaction (SN2) driving strategy to idealize the robust buried interface by simultaneously decorating underlying substrate and functionalizing [PbX6]4- octahedral framework with iodoacetamide and thiol molecules, respectively. Theoretical and experimental results demonstrate that a strong SN2 reaction between exposed halogen and thiol group in two molecules occurs, which not only benefits the reinforcement of buried adhesion, but also triggers target-point-oriented crystallization, synergistically upgrading the upper perovskite film quality and accelerating interfacial charge extraction-transfer behavior. Benefiting from the suppressed nonradiative recombination, as a result, an all-air-processed carbon-based all-inorganic CsPbI2Br device achieves an enhanced efficiency of 15.14%, more importantly, with significantly prolonged long-term stability under harsh conditions. This unique reaction-driven buried interface provides a new path for manipulating perovskite growth and obtaining advanced perovskite photovoltaics.

SN2‐Reaction‐Driven Bonding‐Heterointerface Strengthens Buried Adhesion and Orientation for Advanced Perovskite Solar Cells

Traditionally weak buried interaction without customized chemical bonding always goes against the formation of high‐quality perovskite film that highly determines the efficiency and stability of perovskite solar cells. To address this issue, herein, we propose a bimolecular nucleophilic substitution reaction (SN2) driving strategy to idealize the robust buried interface by simultaneously decorating underlying substrate and functionalizing [PbX6]4‐ octahedral framework with iodoacetamide and thiol molecules, respectively. Theoretical and experimental results demonstrate that a strong SN2 reaction between exposed halogen and thiol group in two molecules occurs, which not only benefits the reinforcement of buried adhesion, but also triggers target‐point‐oriented crystallization, synergistically upgrading the upper perovskite film quality and accelerating interfacial charge extraction‐transfer behavior. Benefiting from the suppressed nonradiative recombination, as a result, an all‐air‐processed carbon‐based all‐inorganic CsPbI2Br device achieves an enhanced efficiency of 15.14%, more importantly, with significantly prolonged long‐term stability under harsh conditions. This unique reaction‐driven buried interface provides a new path for manipulating perovskite growth and obtaining advanced perovskite photovoltaics.

Selenium Nucleophilicity and Electrophilicity in the Intra- and Intermolecular SN2 Reactions of Selenenyl Sulfide Probes.

Chalcogenide exchange reactions are an important class of bimolecular nucleophilic substitution reactions (SN2) involving sulfur and selenium species as nucleophile, central atom, and/or leaving group, which are fundamental throughout redox biology and metabolism. While thiol-disulfide exchange reactions have been deeply investigated, those involving selenium are less understood, especially with regards to the polarised selenenyl sulfides RSe-SR' even though the directed reactivity of selenenyl sulfides is biologically crucial for selenoenzymes such as thioredoxin reductase (TrxR) and glutathione peroxidase (GPx). Synthetic methods to create asymmetric selenenyl sulfides with high regiochemical purity only emerged over the last five years; this functional group has already demonstrated powerful applications to cell biology, through probes for molecular imaging (e.g. the TrxR probe "RX1") or reagents for thiol-mediated uptake (e.g. remote ammonium thiaselenanes). Here, we investigate the SN2@S and SN2@Se reactions of selenenyl sulfides in silico to provide the first comprehensive overview of their kinetic and thermodynamic trends, referencing against symmetrical disulfides and diselenides. We quantify the role of alternative exchange reactions in the double-exchange chemistry of RX1. This analysis rationalises the origins of RX1's TrxR-specificity even within thiol-rich cellular environments and can support the design and applications of a range of selenenyl sulfide-based bioactive probes.

Redox-Active Bisphosphonate-Based Viologens as Negolytes for Aqueous Organic Flow Batteries.

Viologen derivatives feature two reversible one-electron redox processes and have been extensively utilized in aqueous organic flow batteries (AOFBs). However, the early variant, methyl viologen (MVi), exhibits low stability in aqueous electrolytes, restricting its practical implementation in AOFB technology. In this context, leveraging the tunability of organic molecules, various substituents have been incorporated into the viologen core to achieve better stability, lower redox potential, and improved solubility. In this work, we introduce bisphosphonate-substituted viologens as candidates for AOFBs. The bulkiness and negative charges of the bisphosphonate groups enhance the solubility and the electrostatic repulsion among viologen molecules, minimizing the bimolecular side reactions that lead to degradation. Additionally, the electron-donating effect of this new substituent significantly lowers the redox potential. As a result, the proposed viologen derivatives exhibit high solubility (1.66 - 1.81 M in water) and stability (capacity decay of 0.009%/cycle or 0.229%/day when tested at 0.5 M). These parameters are coupled with the lowest redox potentials exceeding all previously reported viologens utilized in AOFBs (-0.503 V and -0.550 V against SHE for mono- and bis-phosphonate viologen, respectively).

Derivation of atmospheric reaction mechanisms for volatile organic compounds by the SAPRC mechanism generation system (MechGen)

Abstract. This paper describes the methods that are used in the SAPRC mechanism generation system, MechGen, to estimate rate constants and derive mechanisms for gas-phase reactions of volatile organic compounds (VOCs) in the lower atmosphere. Versions of this system have been used for over 20 years in the development of the SAPRC mechanisms for air quality models, but this is the first complete documentation of the scientific basis for the chemical mechanisms it derives. MechGen can be used to derive explicit gas-phase mechanisms for most compounds with C, H, O, or N atoms. Included are reactions of organic compounds with hydroxy (OH) and nitrate (NO3) radicals, O3, and O3P; photolysis or unimolecular reactions; and the reactions of the radicals they form in the presence of O2 and oxides of nitrogen (NOx) at lower-atmospheric temperatures and pressures. Measured or theoretically calculated rate constants and branching ratios are used when data are available, but in most cases rate constants and branching ratios are estimated using various structure–reactivity or other estimation methods. Types of reactions include initial reactions of organics with atmospheric oxidants or by photolysis; unimolecular and bimolecular reactions of carbon-centered, alkoxy, and peroxy radicals; and those of Criegee and other intermediates that are formed. This paper documents the methods, assignments, and estimates currently used to derive these reactions and provides examples of MechGen predictions. Many of the estimation methods discussed here have not been published previously, and others have not been used previously in developing comprehensive mechanisms. Our knowledge of atmospheric reactions of organic compounds rapidly and continuously evolves, and therefore mechanism generation systems such as MechGen also need to evolve to continue to represent the current state of the science. This paper points out areas where MechGen may need to be modified when the system is next updated. This paper concludes with a summary of the major areas of uncertainty where further experimental, theoretical, or mechanism development research is most needed to improve predictions of atmospheric reaction mechanisms of volatile organic compounds.

THE IMPACT OF FRACTIONAL COMPOSITION OF GAS OIL ON THE YIELD AND QUALITY OF CATALYTIC CRACKING PRODUCTS

The impact of the depth of selection of narrow gas oil fractions of Azeri-Chirag-Guneshli oils on the yield and quality of catalytic cracking products was studied. The impact of fractional and group hydrocarbon composition on the main directions of cracking is analyzed. 5 types of gas oil fractions selected in the range of 200-360, 200-410, 200-440, 200-460, and 200-500°C were used as feedstock for catalytic cracking. The results of catalytic cracking of narrow gas oil fractions of Azeri-Chirag-Guneshli oils indicate a nonlinear nature of the dependences on the boiling point limits. The highest total yield of light oil products was obtained by cracking gas oil fractions boiling in the range of 200-410 and 200-440°C, reaching 60.5 and 60.8%, respectively. At the same time, the main contribution to this indicator was made by the gasoline fraction (31.5-33.2%). It was based on paraffin-naphthenic hydrocarbons. The yield of the diesel fraction changed symbiotically with the increasing weight of the fractional composition of the raw material, reaching maximum values of 9.9% during the cracking of the gas oil fraction, boiling in the range of 200-500°C. Based on a comparison of the ratio of iso-butane to iso-butylene, it was concluded that the cracking of gas oil at 200-440°C was accompanied by a significant contribution of bimolecular hydrogen transfer reactions.

Pressure-dependent kinetic analysis of the N2H3 potential energy surface.

The pressure-dependent reactions on the N2H3 potential energy surface (PES) have been investigated using CCSD(T)-F12/aug-cc-pVTZ-F12//B2PLYP-D3/aug-cc-pVTZ. This study expands the N2H3 PES beyond the previous literature by incorporating a newly identified isomer, NH3N, along with additional bimolecular reaction channels associated with this isomer, namely NNH + H2 and H2NN(S) + H. Rate coefficients for all relevant pressure-dependent reactions, including well-skipping pathways, are predicted using a combination of ab initio transition state theory and master equation simulations. The dominant product of the NH2 + NH(T) recombination is N2H2 + H, while at high pressures and low temperatures, N2H3 formation becomes significant. Similarly, collisions involving H2NN(S) + H predominantly produce N2H2 + H. Secondary reactions such as H2NN(S) + H ⇌ NNH + H2 and H2NN(S) + H ⇌ NH2 + NH(T) are found to play a significant role at high temperatures across all examined pressures, while H2NN(S) + H ⇌ NH3N becomes prominent only at high pressures. Notably, none of these four H2NN(S) reactions have been included with pressure-dependent rate coefficients in previous NH3 oxidation models. The rate coefficients reported here provide valuable insights for modeling the combustion of ammonia, hydrazine, and their derivatives in diverse environments.

Unraveling the effect of reagent vibrational excitation on the scattering mechanism of the benchmark H + H2 → H2 + H hydrogen exchange reaction in the coupled 12E' ground electronic manifold.

The hydrogen exchange reaction, H + H2 → H2 + H, along with its isotopic variants, has been the cornerstone for the development of new and novel dynamical mechanisms of gas-phase bimolecular reactions since the 1930s. The dynamics of this reaction are theoretically investigated in this work to elucidate the effect of reagent vibrational excitation on differential cross sections (DCSs) in a nonadiabatic situation. The dynamical calculations are carried out using a time-dependent quantum mechanical method, both on the lower adiabatic potential energy surface and employing a two-state coupled diabatic theoretical model to explicitly include all the nonadiabatic couplings present in the 12E' ground electronic manifold of the H3 system. Towards this effort, the Boothroyd-Keogh-Martin-Peterson (BKMP2) surface of the lower adiabatic component is coupled with the double many-body expansion (DMBE) surface of the upper one. The smooth variation of energy along the D3h seam of the conical intersections is explicitly confirmed. The coupled two-state calculations are performed only for H2 (v = 3-4, j = 0), as the minimum of the conical intersections becomes energetically accessible for these vibrational levels in the considered energy range. Initial state-selected total and state-to-state DCSs are calculated to elucidate various mechanistic aspects of reagent vibrational excitation. The latter enhances the forward scattering and makes the backward scattering less prominent. Important roles of collision energy in the vibrational energy disposal of both forward- and backward-scattered products are examined. Analysis of the state-to-state DCSs of the vibrationally excited reagents reveals an important correlation among scattering angle, and the product rotational angular momentum and its helicity state. Such an analysis establishes a novel mechanism for the forward scattering of the reaction.

Exploring Excited-State Intramolecular Proton-Coupled Electron Transfer in Dinuclear Ir(III)-Complex via Covalently Tagged Hydroquinone: Phototherapy Through Futile Redox Cycling.

Anticipating intramolecular excited-state proton-coupled electron transfer (PCET) process within dinuclear Ir2-photocatalytic system via the covalent linkage is seminal, yet challenging. Indeed, the development of various dinuclear complexes is also promising for studying integral photophysics and facilitating applications in catalysis or biology. Herein, this study reports dinuclear [Ir2(bis{imidazo-phenanthrolin-2-yl}-hydroquinone)(ppy)4]2+ (12+) complex by leveraging both ligand-centered redox property and intramolecular H-bonding for exploring dual excited-state proton-transfer assisted PCET process. The vital role of covalently placed hydroquinone in bridged ligand is investigated as electron-proton transfer (ET-PT) mediator in intramolecular PCET and validated from triplet spin density plot. Moreover, bimolecular photoinduced ET reaction is studied in acetonitrile/water medium, forging the lowest energy triplet charge separated (3CSPhen-Im) state of 12+ with methyl viologen via favorably concerted-PCET pathway. The result indicates strong donor-acceptors coupling, which limits charge recombination and enhances catalytic efficiency. To showcase the potential application, this bioinspired PCET-based photocatalytic platform is studied for phototherapeutics, indicating significant mitochondrial localization and leading to programmed cell death (apoptosis) through futile redox cycling. Indeed, the consequences of effective internalization (via energy-dependent endocytosis), better safety profile, and higher photoinduced antiproliferative activity of 12+ compared to Cisplatin, as explored in 3D tumor spheroids, this study anticipates it to be a potential lead compound.

Tropospheric Fate of Methylhydroxycarbene and the Ability of a Single Water Molecule to Efficiently Promote Its Isomerization into Acetaldehyde.

The ultraviolet (UV) photodissociation of pyruvic acid through the absorption of solar actinic flux generates methylhydroxycarbene (MHC) in the atmosphere. It is recognized that isolated MHC can undergo unimolecular isomerization to form acetaldehyde and vinyl alcohol. However, the rates and mechanism for its possible bimolecular reactions with atmospheric constituents, which can occur in parallel with its unimolecular reaction, is not well understood. Here we investigate the energetics, kinetics, and mechanism of the reaction of MHC with three ubiquitous atmospheric molecules N2, O2, and H2O over the 160 K-380 K temperature range. Our study, at the CCSD(T)/6-311++G(3df,3pd)//M06-2X/6-311++G(3df,3pd) level, reveals that the MHC + N2 encounter is nonreactive, while the MHC + O2 reaction, which leads to CH3CO + HO2 formation, has a rate that is significantly different from previous estimates. For the MHC + H2O reaction, we find that a single H2O molecule is very effective in catalyzing the isomerization of MHC to form predominantly acetaldehyde. An analysis of the computed rate for this reaction indicates that it will be an important source of tropospheric acetaldehyde ̵ a major pollutant and precursor for atmospheric reactive intermediates. Our findings are in sharp contrast to current assessments in the literature that the MHC + H2O reaction is minor. Furthermore, in the MHC + H2O reaction system, we find that due to the presence of the OH group on MHC, the concerted insertion mechanism, which is typically dominant in reactions involving singlet carbenes, is suppressed relative to a hydrogen bond mediated double hydrogen atom transfer mechanism.

Loss of bimolecular reactions in reaction-diffusion master equations is consistent with diffusion limited reaction kinetics in the mean field limit.

We show that the resolution-dependent loss of bimolecular reactions in spatiotemporal Reaction-Diffusion Master Equations (RDMEs) is in agreement with the mean-field Collins-Kimball (C-K) theory of diffusion-limited reaction kinetics. The RDME is a spatial generalization of the chemical master equation, which enables studying stochastic reaction dynamics in spatially heterogeneous systems. It uses a regular Cartesian grid to partition space into locally well-mixed reaction compartments and treats diffusion as a jump reaction between neighboring grid cells. As the chance for reactants to be in the same grid cell decreases for smaller cell widths, the RDME loses bimolecular reactions in finer grids. We show that for a single homo-bimolecular reaction, the mesh spacing can be interpreted as the reaction radius of a well-mixed C-K rate. Then, the bimolecular reaction loss is consistent with diffusion-limited kinetics in the mean-field steady state. In this interpretation, the constant in a bimolecular reaction propensity is no longer the macroscopic reaction rate but the rate of the ballistic C-K step. For the same grid resolution, different diffusion models in RDME, such as those based on finite differences and Gaussian jumps, represent different reaction radii.

Parallelization of particle-based reaction-diffusion simulations using MPI.

Particle-based reaction-diffusion models offer a high-resolution alternative to the continuum reaction-diffusion approach, capturing the discrete and volume-excluding nature of molecules undergoing stochastic dynamics. These methods are thus uniquely capable of simulating explicit self-assembly of particles into higher-order structures like filaments, spherical cages, or heterogeneous macromolecular complexes, which are ubiquitous across living systems and in materials design. The disadvantage of these high-resolution methods is their increased computational cost. Here we present a parallel implementation of the particle-based NERDSS software using the Message Passing Interface (MPI) and spatial domain decomposition, achieving close to linear scaling for up to 96 processors in the largest simulation systems. The scalability of parallel NERDSS is evaluated for bimolecular reactions in 3D and 2D, for self-assembly of trimeric and hexameric complexes, and for protein lattice assembly from 3D to 2D, with all parallel test cases producing accurate solutions. We demonstrate how parallel efficiency depends on the system size, the reaction network, and the limiting timescales of the system, showing optimal scaling only for smaller assemblies with slower timescales. The formation of very large assemblies represents a challenge in evaluating reaction updates across processors, and here we restrict assembly sizes to below the spatial decomposition size. We provide the parallel NERDSS code open source, with detailed documentation for developers and extension to other particle-based reaction-diffusion software.

A Quantitative Study of the Halogenophilic Nucleophilic Substitution (SN2X) Reaction and Chalcogenophilic Nucleophilic Substitution (SN2Ch) Reaction.

Halogenophilic nucleophilic substitution (SN2X) has a distinctly different reaction pathway compared to the bimolecular nucleophilic substitution reaction (SN2), but they can lead to the same reaction product. However, their differences can be distinguished by studying stereoselective reactions in which both reaction pathways are possible. Herein, we utilize the stereospecific nature of SN2 and the presence of a pro-chiral anion intermediate in SN2X to conduct a quantitative study in which both SN2 and SN2X reactions exist. We developed a procedure supported by kinetic simulations to measure the halogenophilic percentage (X%). We also developed a new parameter, relative halogenophilicity (H), to quantify the intrinsic characteristics of SN2X reactions and found it to correlate well with the Hammett and Mayr postulates. We studied the time dependency of X% under different reaction conditions, which led to the discovery of two new distinct mechanisms: chalcogenophilic nucleophilic substitution (SN2Ch) reaction and bromide-catalyzed dynamic kinetic resolution. The SN2 and SN2X reactions exhibit similar behavior from both thermodynamic and kinetic perspectives, suggesting that they occur to varying degrees in most of the reactions. Consequently, they are inherently linked and should not be considered in isolation.

Bridging molecular to cellular scales for models of membrane receptor signaling.

In cell signaling, the activation of a surface receptor leads to a cascade of intracellular biochemical events. Many of these occur near the inner plasma membrane surface. However, accurate rate parameters for these initial steps in models of signaling are rarely available because membrane-tethered reaction kinetics are difficult to experimentally measure. Here, we use a highly coarse-grained molecular simulator to model the kinetics of reactions between binding sites that are tethered to a membrane. We can fit these simulation outputs to 2-dimensional rate laws to obtain rate constants that can be used to build complex models of cell signaling. These rate constants can also be compared to understand the key biophysical features controlling the kinetics of bimolecular membrane reactions.

Study on the Effect of Structure and Acidity of Hydrocracking Catalyst Support on the Selectivity of Middle Distillate.

Hydrocracking has become the main technology for producing diesel fuel in many refineries, the key process to meeting new product specifications as environmental regulations for transportation fuels become more stringent. The efficacy of the hydrocracking catalyst is a pivotal determinant of the reaction performance. This study leveraged high-throughput experimentation to closely examine the impact of support properties on both the catalytic activity and the selectivity of middle distillates. The findings show that the catalyst's activity is mainly controlled by the amount of Brönsted acid sites and the presence of strong Lewis acid sites within the carrier. An inverse relationship was observed between middle distillate selectivity and catalyst activity, highlighting a trade-off between these two measures of performance. Furthermore, the hydrocracking performance index (HPI), serving as a composite measure of catalyst efficacy, revealed that an optimal pore size and strong Brönsted acidity are important for increasing the HPI value, thereby signifying enhanced catalytic performance. The experimental result matches the bimolecular hydrogen transfer reaction, which is essential in determining the hydrocracking performance index (HPI) value.

Quenching Rate Constants of Lewis Base-Boryl Radical by Substrates: a Laser Flash Photolysis Study.

The advanced strategy using Lewis base-boryl radicals (LBRs) has recently been proposed for the addition of alkyl substituents to the full-carbon quaternary center of an organic molecule. However, as the rate-determining step in the whole route, reaction rate constants of LBRs with substrates are extremely lacking. In this paper, 4-dimethylaminopyridine (DMAP)-BH2⋅ was selected as a representative of LBRs, and its reactions with six monochloro-substituted substrates, including three methyl chlorobenzoates and three chlorinated acetanilides were studied in experiments and theoretical calculations. The bimolecular reaction rate constants, kq, were determined using laser flash photolysis approach. By comparing activation energies along the two addition pathways, we have clarified the rate-determining step as the attacking to carbonyl oxygen instead of chlorine atom. Furthermore, noncovalent interaction (NCI) analyses on these substrates indicate that weak interactions, such as hydrogen-bonding and van der Waals interactions, have significant influence on the reactivity of these substrates. Our study provides concrete clues to extend this synthetic strategy.