Kinetic and thermodynamic preferences in aryl vs benzylic C-H bond activation with cationic Pt(II) complexes

Anhydrous cationic Pt(II) complexes [(NN)Pt(CH3)(CF3CD2OD)]+ (1, NN = ArN=C(Me)-C(Me)=NAr), which are obtained by reaction of (NN)Pt(CH3)2 with B(C6F5)3 in CF3CD2OD, activate C-H bonds of benzene and methylbenzenes, with enhanced reactivity compared to the previously prepared equilibrium mixtures with the (thermodynamically favored) aquo complexes. For methylbenzenes (toluene, p-xylene, mesitylene), activation at the aromatic and benzylic positions are kinetically competitive, but the product of the latter is strongly favored thermodynamically. This unusual trend is attributed to formation of eta3-benzyl structures, which can be observed spectroscopically for 1,4-diethylbenzene activation.     

Addition of carbenes to the sidewalls of single-walled carbon nanotubes

The addition of carbenes CX(2) (X=H, Cl) to single-walled carbon nanotubes (SWNTs) was investigated by density functional theory and finite, hydrogen-terminated nanotube clusters or periodic boundary conditions in conjunction with basis sets of up to polarized triple-zeta quality. For armchair [(3,3) to (12,12)] and zigzag tubes [(3,0) to (18,0)], reaction of CH(2) with the C--C bond oriented along the tube axis (A) is less exothermic than with those C--C bonds having circumferential (C) orientation. This preference decreases monotonically with increasing tube diameter for armchair, but not for zigzag tubes; here, tubes with small band gaps have a very low preference for circumferential addition. Axial addition results in cyclopropane products, while circumferential addition produces "open" structures for both armchair and zigzag tubes. The barriers for addition of dichlorocarbene to a (5,5) SWNT, studied for a finite C(90)H(20) cluster, are higher than that for addition to C(60), in spite of similar diameters of the carbon materials. Whereas addition of CCl(2) to [60]fullerene proceeds in a concerted fashion, addition to a (5,5) armchair SWNT is predicted to occur stepwise and involve a diradicaloid intermediate according to B3LYP, PBE, and GVB-PP computations. Addition to C bonds of (5,5) armchair tubes resulting in the thermodynamically more stable insertion products is kinetically less favorable than that to A bonds yielding cyclopropane derivatives.     

Reaction of Sulfur with Ga-C Bonds: Synthesis and Characterization of [PyRGaS](3) Formed from Ga(S(2)R)(3) (R = Et, Me)

The reactions of Ga(CH(2)CH(3))(3) with variable amounts of elemental sulfur, S(8), in toluene or benzene at different temperatures result in the insertion of sulfur into the Ga-C bonds to form the compounds Ga[(S-S)CH(2)CH(3)](3) (I) and Ga[(S-S-S)CH(2)CH(3)](3) (II). Compound I was isolated from the reaction at low temperature while at room temperature; compound II was the major product. Compound II exhibited the maximum extent of sulfur insertion even when the reactions were carried out with more than 9.0 equiv of sulfur. The reactions of Ga(CH(3))(3) with various amounts of sulfur in toluene or benzene only result in the formation of compound III, Ga[(S-S)CH(3)](3). In pyridine at -30 degrees C, deinsertion of the sulfur atoms from Ga-S-S-C bonds was observed for the first time from compounds I and III resulting in formation of the six-membered Ga-S ring compounds IV, [PyEtGaS](3), and V, [PyMeGaS](3), respectively. Compounds IV and V were characterized by (1)H NMR, (13)C NMR, elemental analyses, thermogravimetric analysis, and single-crystal X-ray diffraction. Compound IV crystallized in the monoclinic space group P2(1)/n, with a = 9.288(2) ?, b = 14.966(2) ?, c = 19.588(3) ?, beta = 90.690(10) degrees, and Z = 4. Compound V crystallized in the monoclinic space group P2(1)/c, with a = 10.385(1) ?, b = 15.300(2) ?, c = 15.949(2) ?, beta = 107.01(1) degrees, Z = 4, unit cell volume = 2423.5(5) ?(3), R = 0.030, and R(w) = 0.026. The sulfur insertion reaction pathway was investigated by time-dependent and variable-temperature (1)H NMR spectroscopy.     

Chemo- and periselectivity in the addition of [OsO2(CH2)2] to ethylene: a theoretical study

Quantum chemical calculations by using density functional theory at the B3LYP level have been carried out to elucidate the reaction course for the addition of ethylene to [OsO2(CH2)2] (1). The calculations predict that the kinetically most favorable reaction proceeds with an activation barrier of 8.1 kcal mol(-1) via [3+2] addition across the O=Os=CH2 moiety. This reaction is -42.4 kcal mol(-1) exothermic. Alternatively, the [3+2] addition to the H2C=Os=CH2 fragment of 1 leads to the most stable addition product 4 (-72.7 kcal mol(-1)), yet this process has a higher activation barrier (13.0 kcal mol(-1)). The [3+2] addition to the O=Os=O fragment yielding 2 is kinetically (27.5 kcal mol(-1)) and thermodynamically (-7.0 kcal mol(-1)) the least favorable [3+2] reaction. The formal [2+2] addition to the Os=O and Os=CH2 double bonds proceeds by initial rearrangement of 1 to the metallaoxirane 1 a. The rearrangement 1-->1 a and the following [2+2] additions have significantly higher activation barriers (>30 kcal mol(-1)) than the [3+2] reactions. Another isomer of 1 is the dioxoosmacyclopropane 1 b, which is 56.2 kcal mol(-1) lower in energy than 1. The activation barrier for the 1-->1 b isomerization is 15.7 kcal mol(-1). The calculations predict that there are no energetically favorable addition reactions of ethylene with 1 b. The isomeric form 1 c containing a peroxo group is too high in energy to be relevant for the reaction course. The accuracy of the B3LYP results is corroborated by high level post-HF CCSD(T) calculations for a subset of species.     

Addition of a phosphinidene complex to C=N bonds: P-ylides, azaphosphiridines, and 1,3-dipolar cycloadditions

The terminal phosphinidene complex PhPW(CO)5 adds to the imine bond of PhHC=N-Ph to give 3-membered ring azaphosphiridines, which undergo ring-expansion with an additional imine to yield a set of four isomeric five-membered ring diazaphospholanes. Treatment with the diimines PhHC=N-(CH2)n-N=CHPh (n=2,3,4) results instead-in all three cases-in only a single isomer of the (CH2)n bridged diazaphospholane. For n=2 or 3, this aminal group is easily hydrolyzed to afford new 6- and 7-membered ring heterocycles. No intermediate azaphosphiridine complex is observed during the addition reaction to the diimines. B3LYP/6-31G* calculations on an unsubstituted, uncomplexed system suggest that the initially formed P,N-ylide of the H2C=N-(CH)2-N=CH2 diimine both kinetically and thermodynamically favors an intramolecular 1,3-dipolar cycloaddition over an imine insertion into the CPN ring of an intermediate azaphosphiridine. Single-crystal X-ray structures for the (CH2)2-bridged azaphospholane complex and the HCl adduct of the 7-membered hydrolysis product are presented.     

On the behavior of alpha,beta-unsaturated thioaldehydes and thioketones in the Diels-Alder reaction

Alpha,beta-unsaturated thioaldehydes and thioketones, R1CH=CH-C(=S)R2, are prepared in situ by the reaction between the corresponding carbonyl compounds and bis(dimethylaluminum) sulfide. These compounds undergo [4 + 2] self-dimerization reactions in which one molecule serves as the heterodiene component and the other as the dienophile to afford different types of dimeric products depending on the R1 and R2: 1,2-dithiin and 1,3-dithiin (R1 = R2 = H), 1,2-dithiin (R1 = Ph, R2 = H, CH3), or dihydrothiopyran (R1 = R2 = Ph). These differences in selectivity are explained on the basis of the relative energies evaluated by molecular orbital (MO) calculations at the DFT (density functional theory) level. The calculations show that in the dimerization reaction of thioacrolein (I), the head-to-tail (S-C-S bonded) dimers are kinetically more stable by about 5 kcal/mol but slightly thermodynamically unstable by about 2 kcal/mol than the head-to-head (S-S bonded) dimers. The calculations on thiocinnamaldehyde (IV) indicate that the dimerization reactions of phenyl-substituted alpha,beta-unsaturated thioaldehydes and thioketones are almost equally controlled by thermodynamic and kinetic factors. These unsaturated thiocarbonyl compounds also function as heterodienes (C=C-C=S) in the cycloaddition reaction with norbornadiene and as dienophiles (C=S) in the reaction with cyclopentadiene.     

Mechanistic Aspects of Aryl–Halide Oxidative Addition,Coordination Chemistry,and Ring‐Walking by Palladium

This contribution describes the reactivity of a zero‐valent palladium phosphine complex with substrates that contain both an aryl halide moiety and an unsaturated carbon–carbon bond. Although η²‐coordination of the metal center to a C?C or C?C unit is kinetically favored, aryl halide bond activation is favored thermodynamically. These quantitative transformations proceed under mild reaction conditions in solution or in the solid state. Kinetic measurements indicate that formation of η²‐coordination complexes are not nonproductive side‐equilibria, but observable (and in several cases even isolated) intermediates en route to aryl halide bond cleavage. At the same time, DFT calculations show that the reaction with palladium may proceed through a dissociation–oxidative addition mechanism rather than through a haptotropic intramolecular process (i.e., ring walking). Furthermore, the transition state involves coordination of a third phosphine to the palladium center, which is lost during the oxidative addition as the C?halide bond is being broken. Interestingly, selective activation of aryl halides has been demonstrated by adding reactive aryl halides to the η²‐coordination complexes. The product distribution can be controlled by the concentration of the reactants and/or the presence of excess phosphine.     

Lewis碱稳定的硼代苯与亲二烯体的Diels-Alder反应的理论研究

采用密度泛函理论方法在B3LYP/6-31G(d)水平上研究了Lewis碱稳定的硼代苯与一些亲二烯体的两种可能的Diels-Alder反应的微观机理和势能剖面, 并研究了反应的溶剂效应和取代基效应. 计算结果表明, 一部分反应以直接的近同步的协同方式进行, 而在另一部分反应中, 两个反应物分子先形成分子间复合物, 然后再经过协同的过渡态生成产物. 与气相中相比, 二氯甲烷溶剂使所研究的大部分反应的活化能垒有所增加. 在乙炔或乙烯分子中分别引入吸电子基团CO2Me或CN能显著降低反应的活化能垒. 形成一个C—B键的杂Diels-Alder反应都比相应的Diels-Alder反应在热力学和动力学上容易进行, 这与实验结果一致.     

The kinetics of addition and fragmentation in reversible addition fragmentation chain transfer polymerization: An ab initio study

High-level ab initio calculations of the forward and reverse rate coefficients have been performed for a series of prototypical reversible addition fragmentation chain transfer (RAFT) reactions: R* + S=C(Z)SCH3 --> R-SC*(Z)SCH3, for R = CH3, with Z = CH3, Ph, and CH2Ph; and Z = CH3, with R = (CH3), CH2COOCH3, CH2Ph, and C(CH3)2CN. The addition reactions are fast (ca. 10(6)-10(8) L mol(-1) s(-1)), typically around three orders of magnitude faster than addition to the C=C bonds of alkenes. The fragmentation rate coefficients are much more sensitive to the nature of the substituents and vary from 10(-4) to 10(7) s(-1). In both directions, the qualitative effects of substituents on the rate coefficients largely follow those on the equilibrium constants of the reactions, with fragmentation being favored by bulky and radical-stabilizing R-groups and addition being favored by bulky and radical-stabilizing Z-groups. However, there is evidence for additional polar and hydrogen-bonding interactions in the transition structures of some of the reactions. Ab initio calculations were performed at the G3(MP2)-RAD//B3-LYP/6-31G(d) level of theory, and rates were obtained via variational transition state theory in conjunction with a hindered-rotor treatment of the low-frequency torsional modes. Various simplifications to this methodology were investigated with a view to identifying reliable procedures for the study of larger polymer-related systems. It appears that reasonable results may be achievable using standard transition state theory, in conjunction with ab initio calculations at the RMP2/6-311+G(3df,2p) level, provided the results for delocalized systems are corrected to the G3(MP2)-RAD level using an ONIOM-based procedure. The harmonic oscillator (HO) model may be suitable for qualitative "order-of-magnitude" studies of the kinetics of the individual reactions, but the hindered-rotor (HR) model is advisable for quantitative studies.     

磷炔R-C≡P(R=－BH2,－CH3,－NH2,－OH)及其异构体的稳定性

采用B3LYP和CCSD(T)方法对R－C≡P(R=－BH2, －CH3,－NH2, －OH)体系进行了理论研究.结果表明，含C≡P三键的异构体BH2－C≡P和CH3－C≡P在各自的体系中分别是热力学最稳定的结构.而在HO－C≡P和NH2－C≡P体系中，热力学最稳定的结构却是H－P=C=O和含C≡N三键的N≡C－PH2.动力学理论研究表明，没有相关实验研究的R－C≡P(R=－BH2, NH2)体系中共有5种异构体是动力学稳定的. 在HO－C≡P体系的2种动力学稳定的异构体中， H－P=C=O连接方式的异构体已被实验所证实，而另外一种HO－C≡P连接方式的异构体的动力学稳定性较高，实验中可以观察到.对于CH3C≡P体系，研究所预示的2种动力学稳定的异构体中CH3－C≡P已被实验证实，从理论上推测另一种动力学稳定性较高的异构体HC≡C－PH2在实验中也可以检测到.     

Closing the gap between MC3 and MC5 metallacumulenes: the chemistry of the first structurally characterized transition-metal complex with M=C=C=C=CR2 as the molecular unit

The reactions of the dihydrido compound [IrH2Cl(PiPr3)2] (3) with HC identical to CC(O)CHPh2 and HC identical to CC(OAc)=CPh2 lead to the formation of alkynyl-(hydrido)iridium(III) and vinylideneiridium(I) complexes 4-7 which, however, are not suitable precursors for the target molecule trans-[IrCl(=C=C=C=CPh2)-(PiPr3)2] (8). Compound 8 has been prepared in 77% yield from 3 and the vinyl triflate HC identical to CC(OTf)=CPh2 in the presence of NEt3. Treatment of 8 with CF3CO2H affords the vinylvinylidene complex trans-[IrCl(=C=CHC(O2C-CF3)=CPh2)(PiPr3)2] (10) by addition of the electrophile to the C beta-C gamma bond of the MC4 chain. In contrast, the reaction of 8 with HCl yields the five-coordinate butadienyliridium(III) compound [IrCl2-(eta 1-(Z)-CH=CHC(Cl)=CPh2)(PiPr3)2] (11). Salt metathesis of 8 with KI, KOH, and NaN3 leads to the formation of the substitution products trans-[IrX-(=C=C=C=CPh2)(PiPr3)2] (12-14) of which the hydroxo derivative 13 reacts with phenol to give trans-[Ir(OPh)(=C=C=C=CPh2)(PiPr3)2] (15). From 13 and methanol, the octahedral dihydridoiridium(III) complex [IrH2(CH=C=C=CPh2)(CO)(PiPr3)2] (16) is formed by fragmentation of the alcohol. In the presence of CO, both the methyl compound trans-[Ir(CH3)(=C=C=C=CPh2)-(PiPr3)2] (17) (generated from 8 and CH3Li) and the azido complex 14 (X=N3) undergo migratory insertion reactions to yield the four-coordinate iridium(I) carbonyls trans-[Ir(C(C identical to CCH3)=CPh2)(CO)(PiPr3)2] (18) and trans-[Ir(C identical to CC(N3)=CPh2)(CO)(PiPr3)2] (19), respectively. Compound 19 rearranges slowly to the thermodynamically more stable isomer trans-[Ir(C(N3)=C=C=CPh2)(CO)(PiPr3)2] (20). The molecular structures of 8 and 18 have been determined crystallographically.     

Co-Generation of C2 Hydrocarbons and Synthesis Gases from Methane and Carbon Dioxide： a Thermodynamic Analysis

This paper deals with thermodynamic chemical equilibrium analysis using the method of direct minimization of Gibbs free energy for all possible CH4 and CO2 reactions. The effects of CO2/CH4 feed ratio, reaction temperature, and system pressure on equilibrium composition, conversion, selectivity and yield were studied. In addition, carbon and no carbon formation regions were also considered at various reaction temperatures and CO2/CH4 feed ratios in the reaction system at equilibrium. It was found that the reaction temperature above 1100 K and CO2/CH4 ratio=1 were favourable for synthesis gas production with H2/CO ratio unity, while carbon dioxide oxidative coupling of methane （CO2 OCM） reaction to produce ethane and ethylene is less favourable thermodynamically. Numerical results indicated that the no carbon formation region was at temperatures above 1000 K and CO2/CH4 ratio larger than 1.     

Selective cyclopalladation of R3P=NCH2Aryl iminophosphoranes. Experimental and computational study

The orientation of the orthopalladation of iminophosphoranes R3P=NCH2Aryl (R=Ph, Aryl=Ph (1a), C6H(4)-2-Br (1b), C6H4-Me-2 (1e), C6H3-(Me)(2)-2,5 (1f); R=p-tolyl, Aryl=Ph (1c); R=m-tolyl, Aryl=Ph (1d); R3P=MePh2P, and Aryl=Ph (1g)) has been studied. 1a reacts with Pd(OAc)2 (OAc=acetate) giving endo-[Pd(micro-Cl){C,N-C6H4(PPh2=NCH2Ph)-2}]2 (3a), while exo-[Pd(micro-Br){C,N-C6H4(CH2N=PPh3)-2}]2 (3b) could only be obtained by the oxidative addition of 1b to Pd2(dba)3. The endo form of the metalated ligand is favored kinetically and thermodynamically, as shown by the conversion of exo-[Pd(micro-OAc){C,N-C6H4(CH2N=PPh3)-2}]2 (2b) into endo-[Pd(micro-OAc){C,N-C6H4(PPh2=NCH2Ph)-2}]2 (2a) in refluxing toluene. The orientation of the reaction is not affected by the introduction of electron-releasing substituents at the Ph rings of the PR3 (1c and 1d) or the benzyl units (1e and 1f), and endo complexes (3c-3f) were obtained in all cases. The palladation of MePh2P=NCH2Ph (1g) can be regioselectively oriented as a function of the solvent. The exo isomer [Pd(micro-Cl){C6H4(CH2N=PPh2Me)-2}]2 (exo-3g) is obtained in refluxing CH2Cl2, while endo-[Pd(micro-Cl){C,N-C6H4(PPh(Me)=NCH2Ph)-2}]2 (endo-3g) can be isolated as a single isomer in refluxing toluene. In this case, the exo metalation is kinetically favored while an endo process occurs under thermodynamic control, as shown through the rearrangement of [Pd(micro-OAc){C6H4(CH2N=PPh2Me)-2}]2 (exo-2g) into [Pd(micro-OAc){C,N-C6H4(P(Ph)Me=NCH2Ph)-2}]2 (endo-2g) in refluxing toluene. The preference for the endo palladation of 1a and the kinetic versus thermodynamic control in 1g has been explained through DFT studies of the reaction mechanism.     

Alkyne and ketone induced novel cleavage of a CC bond and a CSi bond in zirconacyclobutene-silacyclobutene fused ring compounds

Novel cleavage patterns of CC bonds and CSi bonds were achieved via alkyne- or ketone-induced reactions of zirconacyclobutene-silacyclobutene fused ring compounds; thermodynamically favored six-membered zirconacyclohexadiene derivatives were formed in excellent yields from the four-membered zirconacyclobutenes via this unprecedented alkyne-induced CC bond and CSi bond cleavage process.     

A theoretical study of abiotic methylation reactions of gaseous elemental mercury by halogen-containing molecules

Methylation reactions of gaseous elementary mercury by halogen containing molecules such as halogenomethane species CH(3)X (with X = Cl, Br, and I) and the dimethylchlorinium ion CH(3)ClCH(3)(+) were investigated at the density functional level. With CH(3)X, the reaction is predicted to be almost athermic and kinetically demanding for a thermal reaction. The reaction can proceed photochemically in the visible range; therefore sunlight may increase the reaction rate. These results compare well with the experimental data. Consecutive methylation of the CH(3)HgX products (with X = Cl, Br, and I) and subsequent formation of CH(3)HgCH(3) were also studied. These reactions are predicted to be kinetically inaccessible and thermodynamically unfavorable. With CH(3)ClCH(3)(+), the reaction is predicted to be athermic but kinetically easy. This is due to the suitability of the methyl transfer reagent. Geometrical and electronic data were systematically analyzed in order to rationalize the results.     

Kinetic and theoretical study of 4-exo ring closures of carbamoyl radicals onto C=C and C=N bonds

Carbamoyl radicals were generated from oxime oxalate amides, and the kinetics of their 4-exo cyclizations onto C=C and C=NO bonds, leading to beta-lactam-containing species, were studied by EPR spectroscopy. DFT computations with model carbamoyl radicals predicted 4-exo ring closures onto C=NO bonds to be facile, especially when tert-butyl substituents were present. The reverse ring-opening reactions were predicted to have much higher activation energies. Experimental evidence also favored slow reverse ring opening.     

Hydrogen atom transfer reactions of C2-, C4-, and C6-: bond dissociation energies of linear H-C2n- and H-C2n (n = 1, 2, 3)

The reactions of C2-, C4-, and C6- with D2O and ND3 and of C4- with CH3OH, CH4, and C2H6 have been investigated using guided ion beam tandem mass spectrometry. Hydrogen (or deuterium) atom transfer is the major product channel for each of the reactions. The reaction threshold energies for collisional activation are reported. Several of the reactions exhibit threshold energies in excess of the reaction endothermicity. Potential energy calculations using density functional theory show energy barriers for some of the reactions. Dynamic restrictions related to multiple wells along the reaction path may also contribute to elevated threshold energies. The results indicate that the reactions with D2O have the smallest excess threshold energies, which may therefore be used to derive lower limits on the C-H bond dissociation energies of the C2nH- and C2nH (n = 1-3) linear species. The experimental lower limits for the bond dissociation energies of the neutral radicals to linear products are D0(C2-H) >or= 460 +/- 15 kJ/mol, D0(C4-H) >or= 427 +/- 12 kJ/mol, and D0(C6-H) >or= 405 +/- 11 kJ/mol.     

Theoretical study on the identity ion pair SN2 reactions of LiX with CH3SX (X=Cl, Br, and I): structure, mechanism, and potential energy surface

Three archetypal ion pair nucleophilic substitution reactions at the methylsulfenyl sulfur atom LiX+CH3SX-->XSCH3+LiX (X=Cl, Br, and I) are investigated by the modified Gaussian-2 theory. Including lithium cation in the anionic models makes the ion pair reactions proceed along an SN2 mechanism, contrary to the addition-elimination pathway occurring in the corresponding anionic nucleophilic substitution reactions X-+CH3SX-->XSCH3+X-. Two reaction pathways for the ion pair SN2 reactions at sulfur, inversion and retention, are proposed. Results indicate the inversion pathway is favorable for all the halogens. Comparison of the transition structures and energetics for the ion pair SN2 at sulfur with the potential competition ion pair SN2 reactions at carbon LiX+CH3SX-->XCH3+LiXS shows that the SN2 reactions at carbon are not favorable from the viewpoints of kinetics and thermodynamics.     

Elimination of HX (X = Cl,Br) from haloalkenes on the Ru2Q2 (Q = S,Se) core complex

Treatment of [[Ru(P(OCH3)3)2(CH3CN)3]2(mu-Q2)](CF3SO3)4 (1, Q = S; 2, Q = Se) with haloalkenes resulted in the formation of complexes carrying unsaturated C3Q2 five-membered or C4Q2 six-membered rings via elimination of HX (X = Cl, Br). The reactions of 1 and 2 with allyl bromide gave the corresponding addition products, [[Ru(P(OCH3)3)2(CH3CN)3]2(mu-QCH=CHCH2Q)](CF3SO3)4 (3, Q = S; 4, Q = Se), via elimination of HBr. The elimination process seems to be thermodynamically controlled and takes place at the final stage of the reaction. The steric effect of the halogen atoms seems more operative than the electronic one.     

Theoretical study on the methyl radical with chlorinated methyl radicals CH(3-n)Cln (n = 1, 2, 3) and CCl2

Radical-radical reactions involving chlorinated methyl radicals are particularly important in the mechanism of combustion of chlorinated hydrocarbons. Yet, they are usually difficult to study experimentally. In this paper, four chloride-related radical-radical reactions, i.e., CH3+CH(3-n)Cln (n = 1, 2, 3) and CH3+CCl2, are theoretically studied for the first time by means of the Gaussian-3//B3LYP potential energy surface survey combined with the master equation study over a wide range of temperatures and pressures. Our calculated results show that the three CH3+CH(3-n)Cln reactions can barrierlessly generate the former two kinetically allowed products P1 H(2)C=C(H)(3-n)Cl(n-1)+HCl and P2 CH3CH(3-n)Cl(n-1)+Cl with the very high predominance of P1 over P2. For the CH3 reaction with the biradical CCl2, which inevitably takes place during the CH3+CCl3 reaction and yet has never been studied experimentally or theoretically, H(2)C=CCl2+H and H(2)C=C(H)Cl+Cl are predicted to be the respective major and minor products. The results are compared with the recent laser photolysis/photoionization mass spectroscopy study on the CH3+CH(3-n)Cln (n = 1, 2, 3) reactions. The predicted rate constants and product branching ratios of the CH3+CCl2 reaction await future experimental verification.