Electron attachment and detachment, and the electron affinities of C5F5N and C5HF4N

Rate constants have been measured for electron attachment to C5F5N (297-433 K) and to 2, 3, 5, 6-C5HF4N (303 K) using a flowing-afterglow Langmuir-probe apparatus (at a He gas pressure of 133 Pa). In both cases only the parent anion was formed in the attachment process. The attachment rate constants measured at room temperature are 1.8 +/- 0.5 X 10(-7) and 7 +/- 3 X 10(-10) cm(-3) s(-1), respectively. Rate constants were also measured for thermal electron detachment from the parent anions of these molecules. For C5F5N- detachment is negligible at room temperature, but increases to 2530 +/- 890 s(-1) at 433 K. For 2, 3, 5, 6-C5HF4N-, the detachment rate at 303 K was 520 +/- 180 s(-1). The attachment/detachment equilibrium yielded experimental electron affinities EA(C5F5N)=0.70 +/- 0.05 eV and EA(2, 3, 5, 6-C5HF4N)=0.40 +/- 0.08 eV. Electronic structure calculations were carried out for these molecules and related C5HxF5-xN using density-functional theory and the G3(MP2)//B3LYP compound method. The EAs are found to decrease by 0.25 eV, on average, with each F substitution by H. The calculated EAs are in good agreement with the present experimental results.     

Identification of the radical anions of C2N4S2 and P2N4S2 rings by in situ EPR spectroelectrochemistry and DFT calculations

The previously unknown radical anions of unsaturated E2N4S2 ring systems (E=RC, R2NC, R2P) can be generated voltammetrically by the one-electron reduction of the neutral species and, despite half-lives on the order of a few seconds, have been unambiguously characterized by electron paramagnetic resonance (EPR) spectroelectrochemistry using a highly sensitive in situ electrolysis cell. Cyclic voltammetric studies using a glassy-carbon working electrode in CH3CN and CH2Cl2 with [nBu4N][PF6] as the supporting electrolyte gave reversible formal potentials for the [E2N4S2]0/- process in the range of -1.25 to -1.77 V and irreversible peak potentials for oxidation in the range of 0.66 to 1.60 V (vs the Fc+/0 couple; Fc=ferrocene). Reduction of the neutral compound undergoes an electrochemically reversible one-electron transfer, followed by the decay of the anion to an unknown species via a first-order (chemical) reaction pathway. The values of the first-order rate constant, kf, for the decay of all the radical anions in CH2Cl2 have been estimated from the decay of the EPR signals for (X-C6H4CN2S)2*-, where X=4-OCH3 (kf=0.04 s(-1)), 4-CH3 (kf=0.02 s(-1)), 4-H (kf=0.08 s(-1)), 4-Cl (kf=0.05 s(-1)), 4-CF3 (kf=0.05 s(-1)), or 3-CF3 (kf=0.07 s(-1)), and for [(CH3)3CCN2S]2*- (kf=0.02 s(-1)), [(CH3)2NCN2S]2*- (kf=0.05 s(-1)), and [(C6H5)2PN2S]2*- (kf=0.7 s(-1)). Values of kf for X=4-H and for [(CH3)2NCN2S]2*- were also determined from the cyclic voltammetric responses (in CH2Cl2) and were both found to be 0.05 s(-1). Possible pathways for the first-order anion decomposition that are consistent with the experimental observations are discussed. Density functional theory calculations at the UB3LYP/6-31G(d) level of theory predict the structures of the radical anions as either planar (D2h) or folded (C2v) species; the calculated hyperfine coupling constants are in excellent agreement with experimental results. Linear correlations were observed between the voltammetrically determined potentials and both the orbital energies and Hammett coefficients for the neutral aryl-substituted rings.     

Photoelectron spectroscopic and theoretical study of aromatics-Pb(m) anionic complexes (aromatics = C6H5, C5H4N, C4H3O, and C4H4N; m = 1-4): a comparative study

The reactions between lead vapored by laser ablation and different aromatic molecules (C6H6, C5H5N, C4H4O, or C4H5N) seeded in argon carrier gas were studied by a reflectron time-of-flight mass spectrometer (RTOF-MS) with a photoelectron spectrometer. The adiabatic electron affinities (EAs) of the dominant anionic products PbmC6H5(-), Pb(m)C5H4N(-) (m = 1-4) and Pb(m)C4H3 (-), Pb(m)C4H4N(-) (m = 1-3) dehydrogenated complexes are obtained from the photoelectron spectra with 308 and 193 nm photon, respectively. It is found that the EAs of Pb(m)C4H4N are higher than those of Pb(m)C6H5, Pb(m)C5H4N, and Pb(m)C4H3O with the same metal number m. The possible structures for Pb(m)C4H4N(-) complexes were calculated with density functional theory (DFT) and the most stable structure was confirmed. The adiabatic detachment energies for the most stable structure were in agreement with the experimental PES results. The calculated density of state (DOS) agrees with the experimental PES spectrum well. It was confirmed by the theoretical calculations that the C4H4N group bonds on lead clusters through the Pb-N sigma bond.     

Slow electron velocity-map imaging spectroscopy of the C4H- and C4D- anions

High resolution photodetachment spectra of C4H- and C4D- obtained via slow electron velocity-map imaging (SEVI) are presented. The spectra reveal closely spaced transitions to the neutral 2Sigma+ and 2Pi states which can be distinguished based on the corresponding photoelectron angular distributions. The C4H ground state is confirmed as the X2Sigma+ state, with the excited A2Pi state lying only 213 cm(-1) higher (201 cm(-1) for C4D). The electron affinities (EAs) are slightly revised to EA (C4H)=28,497+/-8 cm(-1) and EA (C4D)=28,478+/-10 cm(-1). Progressions in low frequency bending vibrations are observed in both states, yielding experimental frequencies of nu7=179(169) cm(-1) and nu6=408(392) cm(-1) for the X2Sigma+ state of C4H (C4D), and nu7=220(215)cm(-1) and nu6=446(437) cm(-1) for the A2Pi state.     

三维超分子化合物[H_2(C_4H_(10)N_2)](SO_4)(H_2O)的制备、晶体结构及差热-热重性质研究

用MnSO4H2O和哌嗪在水-甲醇混合溶剂中反应得到了1个超分子化合物[H2(C4H10N2)](SO4)(H2O) (C4H14N2O5S)。 该晶体属单斜晶系, 空间群为P21/n, 晶胞参数为: a = 6.386(1), b = 11.695(2), c = 11.680(2) ? = 101.06(3), V = 856.1(3) 3, Z = 4, Mr =202.23 , Dc = 1.569 g/cm3, F(000) = 432, ?= 0.368 mm-1。 该化合物是由[H2(C4H10N2)]2+、SO42-、H2O通过氢键自组装而形成的。 其中[H2(C4H10N2)]2+存在2种椅式构象:一种[H2(C4H10N2)]2+与4个SO42-、2个H2O通过氢键相连, 另一种[H2(C4H10N2)]2+则与6个SO42-相连。 它们分别沿着b、c方向交替排列展开, 通过SO42-桥联成二维的层状结构;层与层之间在NH…O、CH…O、OH…O氢键的作用下互相连接, 形成了具有网状结构的三维超分子化合物。 差热及热重测试表明:该化合物从92℃开始分解,首先失去1个H2O, 然后再失去[H2(C4H10N2)]2+和SO4 2-。     

From the tetra(amino) phosphonium cation, [P(NHPh)4]+, to the tetra(imino) phosphate trianion, [P(NPh)4]3-, two-faced ligands that bind anions and cations

The tetraanilino phosphonium cation, [P(N(H)Ph)4]+, 1+, is sequentially deprotonated by Bu(n)Li in thf. The deprotonation reaction of the chloride derivative, Cl, was monitored by (31)P NMR, which revealed the successive formation of the neutral [P(N(H)Ph)3(NPh)], 2, the monoanionic [P(N(H)Ph)2(NPh)2]-, 3-, the dianionic [P(N(H)Ph)(NPh)3]2-, 4(2-), and finally the trianionic species [P(NPh)(4)](3-), (3-). Considering the isoelectronic relationship of oxo, =O, and imino groups, =NR, as well as hydroxy, -OH, and amino groups, -N(H)R, the neutral complex corresponds to phosphoric acid, H3PO4, whereas the anions 3-, 4(2-) and 5(3-) are analogues of dihydrogen phosphate, H2PO4-, monohydrogenphosphate, HPO4(2-), and orthophosphate ions, PO4(3-), respectively. Solid state structures were obtained of 1Cl, 2LiCl(thf)(2), 3Li(thf)(3.5), 3Li(2)Cl(thf)(4.25), 3Li(2)Cl(thf)(6) and 5Li(4)Cl(thf)(4). All systems provide two separate N-P-N chelation sites at opposite ligand faces, either consisting of the di(amino) arrangement P(NH)(2), acting as a double H-bond donor, the di(imino) arrangement PN(2), donating two electron pairs, or the mixed amino imino arrangement P(N)(NH), which supplies both electron pair and H-donor site. Interesting in this aspect is the mixed amino imino derivative 3- which has the ability to chelate a Lewis acid, such as a metal ion, at one face and a Lewis base, such as an anionic or neutral donor at the opposite ligand face. The formation of 1-D aggregates and the entrapment of lithium chloride are key characteristics of the supramolecular structures of the discussed complexes.     

Coordination polymers based on cobridging of rigid and flexible spacer ligands: syntheses, crystal structures, and magnetic properties of [Mn(bpy)(H2O)(C4H4O4)].0.5bpy, Mn(bpy)(C5H6O4), and Mn(bpy)(C6H8O4)

Reactions of 4,4'-bipyridine (bpy) with Mn(C(4)H(4)O(4)).4H(2)O and Mn(C(5)H(6)O(4)).4H(2)O in methanolic aqueous solutions yielded [Mn(bpy)(H(2)O)(C(4)H(4)O(4))].0.5bpy (1) and Mn(bpy)(C(5)H(6)O(4)) (2), respectively, and reactions of freshly prepared Mn(OH)(2)(-)(2)(x)(CO(3))(x).yH(2)O, adipic acid and 4,4'-bipyridine in a methanolic aqueous solution afforded Mn(bpy)(C(6)H(8)O(4)) (3). The six-coordinate Mn atoms in 1 are interlinked by flexible succinato ligands to form layers, which are sustained by rigid bpy ligands into an 3D open framework with the free bpy molecules in tunnels. The ribbonlike chains in 2 result from Mn atoms bridged by glutarato ligands and are connected by bpy ligands into open layers. In 3, the Mn atoms are bridged by both bpy and adipato ligands to form 3D nanoporous frameworks and 2-fold interpenetration of the resulting 3D frameworks completes the crystal structure. In comparison with 1 and 2, compound 3 displays significant antiferromagnetic behavior at low temperature. The antiferromagnetic exchange becomes stronger from 1 through 2 to 3, and the antiferromagnetic ordering of Mn(2+) centers is related to the syn-syn bridging mode of the terminal carboxylate groups of alpha,omega-dicarboxylate anions. Crystal data: C(19)H(18)MnN(3)O(5) (1), monoclinic P2(1)/c, a= 11.686(2) A, b = 17.847(2) A, c = 8.852(1) A, beta = 99.67(1) degrees, V = 1819.9(4) A(3), Z = 4, D(c) = 1.545 g.cm(-3); C(15)H(14)MnN(2)O(4) (2), triclinic P, a = 8.145(2) A, b = 9.574(2) A, c = 10.180(1) A, alpha = 108.01(3) degrees, beta = 93.55(3) degrees, gamma = 105.30(1) degrees, V = 719.2(2) A(3), Z = 2, D(c) = 1.576 g.cm(-3); C(15)H(14)MnN(2)O(4) (3), triclinic P, a = 8.544(1) A, b= 8.881(1) A, c = 10.949(2) A, alpha = 108.81(1) degrees, beta = 95.40(1) degrees, gamma = 101.94(1) degrees, V = 757.7(2) A(3), Z = 2, D(c) = 1.557 g.cm(-3).     

The Interaction of C60, C70, and C60(CN)2 radical anions with cobalt(II) tetraphenylporphyrin in solid multicomponent complexes

A method for the synthesis of the multicomponent ionic complexes: [Cr(I)(C(6)H(6))(2) (.+)][Co(II)(tpp)(fullerene)(-)].C(6)H(4)Cl(2), comprising bis(benzene)chromium (Cr(C(6)H(6))(2)), cobalt(II) tetraphenylporphyrin (Co(II)(tpp)), fullerenes (C(60), C(60)(CN)(2), and C(70)), and o-dichlorobenzene (C(6)H(4)Cl(2)) has been developed. The monoanionic state of the fullerenes has been proved by optical absorption spectra in the UV/vis/NIR and IR ranges. The crystal structures of the ionic [[Cr(I)(C(6)H(6))(2)](.+)](1.7)[[Co(II)(tpp)(C(60))](2)](1.7-). 3.3 C(6)H(4)Cl(2) and [[Cr(I)(C(6)H(6))(2)] (.+)](2)[Co(II)(tpp)[C(60)(CN)(2)]](-)[C(60)(CN)(2) (.-)]).3 C(6)H(4)Cl(2) are presented. The essentially shortened Co.C(fullerene) bond lengths of 2.28-2.32 A in these complexes indicate the formation of sigma-bonded [Co(II)(tpp)][fullerene](-) anions, which are diamagnetic. All the ionic complexes are semiconductors with room temperature conductivity of 2 x 10(-3)-4 x 10(-6) S cm(-1), and their magnetic susceptibilities show Curie-Weiss behavior. The neutral complexes of Co(II)(tpp) with C(60), C(60)(CN)(2), C(70), and Cr(0)(C(6)H(6))(2), as well as the crystal structures of [Co(II)(tpp)](C(60)).2.5 C(6)H(4)Cl(2), [Co(II)(tpp)](C(70)). 1.3 CHCl(3).0.2 C(6)H(6), and [Cr(0)(C(6)H(6))(2)][Co(II)(tpp)] are discussed. In contrast to the ionic complexes, the neutral ones have essentially longer Co.C(fullerene) bond lengths of 2.69-2.75 A.     

Raman,infrared and force field studies of K2(12)C2O4 x H2O and K2(13)C2O4 x H2O in the solid state and in aqueous solution,and of (NH4)2(12)C2O4 x H2O and (NH4)2(13)C2O4 x H2O in the solid state

The Raman and infrared spectra of solid K2(12)C2O4 x H2O are reported together with, for the first time, the corresponding Raman and infrared spectra of solid K2(13)C2O4 x H2O. Raman spectra of aqueous solutions of both isotopomers are also reported. In the solid state the oxalate anion is planar with D2h symmetry in this salt, whereas in aqueous solution the Raman spectra of the anion are best interpreted on the basis of D2d symmetry. The Raman spectra of solid (NH4)2(12)C2O4 x H2O and (NH4)2(13)C2O4 x H2O, in which the oxalate anion is twisted from planarity by 28 degrees about the CC bond, have also been recorded. Several reassignments have been made. The harmonic force field for the oxalate anion in the D2h, D2 and D2d geometries has been determined in part, and approximate values of key valence force constants determined. All the observed band wavenumbers and 12C/13C isotopic shifts are well reproduced by the force fields. The potential energy distribution of the totally symmetric normal modes of planar oxalate indicates that each mode consists of extensively mixed symmetry corrdinates and that the labels previously used for the bands seen here at 475 and 879 cm(-1) would better be described as v(CC) and deltaS(CO2), respectively, putting them in the same wavenumber order as v(NN) and deltaS(NO2) for the isoelectronic and isostructural molecule N2O4. The stretching force constants of N2O4 and planar C2O4(2-) are established to be in the order f(NN) < f(CC) and f(NO) > f(CO), consistent with the known relative bond lengths.     

Two new double Rydberg anions plus access to excited states of neutral Rydberg radicals via anion photoelectron spectroscopy

We have observed and characterized two new double Rydberg anions N6H19- and N7H22- through their anion photoelectron spectra. The vertical detachment energies of these anions were found to be 0.443 and 0.438 eV, respectively. In addition, for three of the seven double Rydberg anions now known, we measured photodetachment transitions not only to the ground electronic states of their corresponding neutral Rydberg radicals but also to their first electronically excited states. In each spectrum, the energy spacing between the resulting peaks provided the ground-to-first electronically excited-state transition energy for the double Rydberg anion's corresponding neutral Rydberg radical. For the radicals, N4H13, N5H16, and N6H19, the spacings were found to be 0.83, 0.70, and 0.67 eV, respectively. These values are in excellent agreement with ground-to-first excited-state transition energies measured in absorption for the same neutral Rydberg radicals by Fuke and co-workers [Eur. Phys. J. D 9, 309 (1999); J. Phys. Chem. A 106, 5242 (2002).] The duplication of this neutral Rydberg property by photodetachment of double Rydberg anions further confirms that double Rydberg anions are indeed the negative ions of their corresponding neutral Rydberg molecules and cluster-like systems.     

H atom yields from the reactions of CN radicals with C2H2, C2H4, C3H6, trans-2-C4H8, and iso-C4H8

The kinetics and H atom channel yield at both 298 and 195 K have been determined for reactions of CN radicals with C2H2 (1.00+/-0.21, 0.97+/-0.20), C2H4 (0.96+/-0.032, 1.04+/-0.042), C3H6 (pressure dependent), iso-C4H8 (pressure dependent), and trans-2-C4H8 (0.039+/-0.019, 0.029+/-0.047) where the first figure in each bracket is the H atom yield at 298 K and the second is that at 195 K. The kinetics of all reactions were studied by monitoring both CN decay and H atom growth by laser-induced fluorescence at 357.7 and 121.6 nm, respectively. The results are in good agreement with previous studies where available. The rate coefficients for the reaction of CN with trans-2-butene and iso-butene have been measured at 298 and 195 K for the first time, and the rate coefficients are as follows: k298K=(2.93+/-0.23)x10(-10) cm3 molecule(-1) s(-1), k195K=(3.58+/-0.43)x10(-10) cm3 molecule(-1) s(-1) and k298K=(3.17+/-0.10)x10(-10) cm3 molecule(-1) s(-1), k195K=(4.32+/-0.35)x10(-10) cm3 molecule(-1) s(-1), respectively, where the errors represent a combination of statistical uncertainty (2sigma) and an estimate of possible systematic errors. A potential energy surface for the CN+C3H6 reaction has been constructed using G3X//UB3LYP electronic structure calculations identifying a number of reaction channels leading to either H, CH3, or HCN elimination following the formation of initial addition complexes. Results from the potential energy surface calculations have been used to run master equation calculations with the ratio of primary:secondary addition, the average amount of downward energy transferred in a collision DeltaEd, and the difference in barrier heights between H atom elimination and an H atom 1, 2 migration as variable parameters. Excellent agreement is obtained with the experimental 298 K H atom yields with the following parameter values: secondary addition complex formation equal to 80%, DeltaEd=145 cm(-1), and the barrier height for H atom elimination set 5 kJ mol(-1) lower than the barrier for migration. Finally, very low temperature master equation simulations using the best fit parameters have been carried out in an increased precision environment utilizing quad-double and double-double arithmetic to predict H and CH3 yields for the CN+C3H6 reaction at temperatures and pressures relevant to Titan. The H and CH3 yields predicted by the master equation have been parametrized in a simple equation for use in modeling.     

Two dinuclear iron(II) complexes K[Fe2(L1)(SCN)4]·2(C3H8O) and [Fe2(L1)(SeCN)3(C5H5N)]·H2O are stabilised in the '[HS-LS]' state by a bis-tetradentate pyrazolate-based ligand

Two air-sensitive dinuclear iron(II) complexes, K[Fe(II)(2)(L(1))(SCN)(4)]·2(C(3)H(8)O) (1) and [Fe(II)(2)(L(1))(SeCN)(3)(C(5)H(5)N)]·H(2)O (2), of 3,5-bis[N,N-bis(2-pyridylmethyl)aminomethyl]-1H-pyrazolate [(L(1))(-)] have been prepared. Interestingly, complex 1 is anionic, featuring four coordinated SCN(-) anions and a potassium counterion whereas complex 2 is neutral, containing a coordinated pyridine molecule and only three coordinated SeCN(-) anions. These are the first iron complexes reported for this type of ligand. Magnetic measurements and M?ssbauer spectra show that both 1 and 2 are in a '[HS-LS]' mixed spin state between 300 and 2 K.     

Stability,metastability, and unstability of three-electron-bonded radical anions. A model ab initio theoretical study

The stability of O therefore O, N therefore N, S therefore S, P therefore P, and Si therefore Si three-electron bonds in anionic radicals isoelectronic to dihalogen radical anions is studied by means of ab initio calculations on model systems. The difficulty of generating the dissociation energy profiles of such anions and their rearrangement to neutral species is solved by a practical method which consists of calculating the neutral and anionic energy profiles separately and shifting the curves with respect to each other to match the experimental energy gap between the asymptotes. Here the neutral and anionic reaction profiles are calculated at the CASPT2 and MP2 levels, respectively. The calculations predict that the O therefore O bond is likely to be observed in anions of the type [RO therefore OR](*-), where R is any alkyl substituent or carbon chain. The anion Si(2)H(6)(*-) is found to be a metastable species, with a fair barrier to electron detachment. The barrier is much smaller for N(2)H(4)(*-) and P(2)H(4)(*-), thus precluding experimental observation. However, these species can be stabilized by electron-attractor substituents, the effect of which can be quantitatively estimated by means of the parent anion's diagrams and some fast complementary calculations. An example is given with the [CF(3)HN therefore NHCF(3)](*-) anionic complex.     

Fentanyl and its analogue N-(1-phenylpyrazol-3-yl)-N-[1-(2-phenylethyl)-4-piperidyl]propanamide: 1H- and 13C-NMR spectroscopy,X-ray crystallography,and theoretical calculations

The oxalate salts and free bases of fentanyl and N-[1-(2-phenylethyl)-4-piperidyl]-N-(1-phenyl-4-pyrazolyl)propanamide, a new lead compound for long-acting analgesia, have been characterized by (1)H- and (13)C-NMR spectroscopy. The crystal structure of the hydrochloride of N-[1-(2-phenylethyl)-4-piperidyl]-N-(1-phenyl-4-pyrazolyl)propanamide monohydrate has been determined. Two centrosymmetrically related cations, joined through C(phenyl)-H em leader pi contacts, encapsulate a large void that contains pairs of anions and bridged water molecules into a zero-dimensional (0D) supramolecular motif. The cations are linked to this framework via N(+)H em leader Cl(-) contacts. GIAO/B3LYP calculations have been carried out to compare the experimental (13)C chemical shifts with the absolute shieldings thus calculated. The protonation of both molecules takes place on the piperidine ring (axial protonation), as has been verified both in the solid state (X-ray) and in solution (NMR).     

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.     

pi-Bonding versus oligomerisation in the aromatic anions [C(6)H(4)N(2)E](-): formation of the cyclic tetrameric tetraanion [C(6)H(4)N(2)Sb](4)(4-)

The reaction of 1,2-(NH(2))(2)C(6)H(4) with Sb(NMe(2))(3)/(n)BuLi gives the formally-aromatic heterocyclic anion [C(6)H(4)N(2)Sb](-) which oligomerises into a cyclic tetrameric arrangement in the complex [C(6)H(4)N(2)SbLi.PMDETA](4) () (PMDETA = {Me(2)NCH(2)CH(2)}(2)NMe) using a donor-acceptor bonding mode that is unique in related main group heterocyclic anions.     

Primary branching ratios for the low-temperature reaction of state-prepared N2+ with CH4, C2H2, and C2H4

Product branching ratios (BRs) are reported for ion-molecule reactions of state-prepared nitrogen cation (N(2)(+)) with methane (CH(4)), acetylene (C(2)H(2)). and ethylene (C(2)H(4)) at low temperature using a modified ion imaging apparatus. These reactions are performed in a supersonic nozzle expansion characterized by a rotational temperature of 40 ± 5K. For the N(2)(+) + CH(4) reaction, a BR of 0.83:0.17 is obtained for the dissociative charge-transfer (CT) reaction that gives rise to the formation of CH(3)(+) and CH(2)(+) product ions, respectively. The N(2)(+) + C(2)H(2) ion-molecule reaction proceeds through a nondissociative CT process that results in the sole formation of C(2)H(2)(+) product ions. The reaction of N(2)(+) with C(2)H(4) leads to the formation of C(2)H(3)(+) and C(2)H(2)(+) product ions with a BR of 0.74:0.26, respectively. The reported BR for the N(2)(+) + C(2)H(4) reaction is supportive of a nonresonant dissociative CT mechanism similar to the one that accompanies the N(2)(+) + CH(4) reaction. No dependence of the branching ratios on N(2)(+) rotational level was observed. In addition to providing direct insight into the dynamics of the state-prepared N(2)(+) ion-molecule reactions with the target neutral hydrocarbon molecules, the reported low-temperature BRs are also important for accurate modeling of the nitrogen-dominated upper atmosphere of Saturn's moon, Titan.     

Electron attachment to SF5X compounds: SF5C6H5, SF5C2H3, S2F10, and SF5Br, 300-550 K

Rate constants and ion product channels have been measured for electron attachment to four SF5 compounds, SF5C6H5, SF5C2H3, S2F10, and SF5Br, and these data are compared to earlier results for SF6, SF5Cl, and SF5CF3. The present rate constants range over a factor of 600 in magnitude. Rate constants measured in this work at 300 K are 9.9+/-3.0x10(-8) (SF5C6H5), 7.3+/-1.8x10(-9) (SF5C2H3), 6.5+/-2.5x10(-10) (S2F10), and 3.8+/-2.0x10(-10) (SF5Br), all in cm3 s-1 units. SF5- was the sole ionic product observed for 300-550 K, though in the case of S2F10 it cannot be ascertained whether the minor SF4- and SF6- products observed in the mass spectra are due to attachment to S2F10 or to impurities. G3(MP2) electronic structure calculations (G2 for SF5Br) have been carried out for the neutrals and anions of these species, primarily to determine electron affinities and the energetics of possible attachment reaction channels. Electron affinities were calculated to be 0.88 (SF5C6H5), 0.70 (SF5C2H3), 2.95 (S2F10), and 2.73 eV (SF5Br). An anticorrelation is found for the Arrhenius A-factor with exothermicity for SF5- production for the seven molecules listed above. The Arrhenius activation energy was found to be anticorrelated with the bond strength of the parent ion.     

CRYSTAL STRUCTURE OF 2, 4-DITHIONE-3-AMINO-1, 3, 2-OX-AZAPHOSPHORINEBENZO-2-THIONO PYRIDINIUM

<正> The structure of title compound [C7H6N2OPS3]-·[HNC5H5]+ was determined by x-ray diffraction. It belongs to monoclinic system with space group P21/a, a = 16.745(2), b= 8.563(2), c=21. 050(5)(?), β=93.32(1)°, V= 3013. 6(?)3, Z = 8, Mr = 341. 4, F (000) = 1536, Dc=1. 504 g. cm-3,μ= 53. 0 cm-1. The crystal is composed of discrete cations C5H5NH+ and anions CrH6N2OPS3-. There are two pairs of the cations and the anions in each asymmetric unit. The stability of the anion is increased by the formation of (d-p)π bonding involving the 3d orbital of the P atom and the lone electron pairs of the S atoms.     

One-dimensional Zigzag Chain Composed of HgI2 Unit and 2,5-Bis（4-pyridyl）- 1,3,4-thiadiazole： [HgI2（C12H8N4S）]

1 INTRODUCTION Much interest has been focused on the design and syntheses of supramolecular coordination polymers with novel topologies and structural motifs because of their encouraging potential applications in the fields of nonlinear optics, catalysis and separation, magnetism and molecular recognition[1, 2]. In princi- ple, control over the type and topology of the coor- dination polymers can be achieved by careful choice of ligand, metal coordination geometry preference, inorganic cou…