Photodissociative production of O(1S) and N(2D) from N2O in an argon matrix at 4 K

Vacuum ultraviolet photolysis of N₂O isolated in Ar matrices at 4 K gives direct luminescent evidence for the photodissociative production of both O(¹S) and N(²D). The matrix results are compared to relative atomic quantum yields measured in the gas phase.     

Influence of Isotope Effects on Product Polarizations of N(2D)+D2, N(2D)+H2 and N(2D)+HD Reactive Systems

To figure out the influence of isotope effect on product polarizations of the N(²D)+D₂ reactive system and its isotope variants, quasi-classical trajectory(QCT) calculation was performed on Ho’s potential energy surface(PES) of ²A″ state. Product polarizations such as product distributions of P(θ_r), P(φ_r) and P(θ_r,φ_r), as well as the generalized polarization-dependent differential cross sections(PDDCSs) were discussed and compared in detail among the four product channels of the title reactions. Both the intermolecular and intramolecular isotope effects were proved to be influential on product polarizations.     

Threshold ion-pair production spectroscopy (TIPPS) of H2 and D2

The threshold ion-pair production spectra at the J" = 0 and J" = 1 thresholds of H2 and J" = 0, 1 and 2 thresholds of D2 obtained with single photon excitation are presented. The ion-pair yield spectra of H2 and D2 over these energy ranges demonstrate strong resonant enhancement, parts of which dominate the TIPPS signals, permitting the assignment of the lower states of these resonances. From those thresholds with weak resonant enhancement (the J" = 0 threshold of H2 and the J" = 1 threshold of D2) a very small direct contribution to ion-pair production can be observed. The behaviour of the TIPPS spectra taken with different applied discrimination fields is understood by modeling the field ionization behaviour of a MATI spectrum of H2, containing both the similarly resonantly enhanced v+ = 8 S(0) ionization threshold and the non-resonantly enhanced S(1) ionization threshold. From the H2 J" = 1 and D2 J" = 0 TIPPS spectra the energetic field-free thresholds of the H2 and D2 ion-pair limits were determined to be 139,714.8 +/- 1.0 cm-1 and 140,370.2 cm-1 +/- 1.0 cm-1, respectively.     

Reaction of O(1D) with N2O

O(¹D), produced from the photolysis of N₂O at 2139 Å, reacts with N₂O in accord with: We have used the method of chemical difference to obtain an accurate measure of k₂/k₃ = 0.59 ± 0.01. Furthermore, the quantum yield of production of O(³P), either on direct photolysis or on deactivation of O(¹D) by N₂O, is less than 0.02 and probably zero.     

Inclined N2 desorption in N2O reduction by D2 and CO on Pd(110)

Inclined N2 desorption was examined in the course of a catalyzed N2O + D2 (or CO) reaction on Pd(110) by angle-resolved mass spectroscopy combined with cross-correlation time-of-flight techniques. N2 desorption collimated at around 45 degrees off the normal toward the [001] direction in the temperature range of 400-800 K. Its collimation angle and kinetic energy were insensitive to both the surface temperature and surface conditions throughout the kinetic transition. It is proposed that this peculiar N2 desorption is induced by the decomposition of N2O oriented along the [001] direction.     

Controlled synthesis and magnetic properties of 2D and 3D iron azide networks infinity2[Fe(N3)2(4,4'-bpy)] and infinity3[Fe(N3)2(4,4'-bpy)

Controlled synthesis of transition metal complexes with mixed ligands has led to two new compounds with the same empirical formula [Fe(N3)2(4,4'-bpy)] (4,4'-bpy=4,4'- bipyridine). The compound 2D-[Fe(N3)2(4,4'-bpy)] (I) contains end-on (EO) bridging azido ligands. It crystallizes in the orthorhombic crystal system, space group Cmmm (No. 65): a=11.444(2) A, b=15.181(3) A, c=3.458(1) A, V=600.8(2) A(3), and Z=2. The compound 3D-[Fe(N3)2(4,4'-bpy)] (II) contains end-to-end (EE) azido bridges. It belongs to the tetragonal crystal system, space group P4(1)2(1)2 (No. 92): a=8.132(1) A, b=8.132(1) A, c=16.708(3) A, V=1104.9(5) A(3), and Z=4. Crystals of I and II have been grown by the diffusion method. Phase-pure samples of both compounds have been obtained by means of an optimal solution synthesis. Spontaneous long-range magnetic ordering was found in both I and II, with I being a metamagnet, and II being a ferromagnet. For I, in the low-field region, multiple transitions at TN1=20 K and TN2=5 K were observed, and these indicated the existence of Fe moment reorientation. Heat capacity measurements on II confirmed ferromagnetic transition at TC=20 K.     

Polydentate N(2)S(2)O and N(2)S(2)O(2) Ligands as Alcoholic Derivatives of (N,N'-Bis(2-mercaptoethyl)-1,5-diazacyclooctane)nickel(II) and (N,N'-Bis(2-mercapto-2-methylpropane)-1,5-diazacyclooctane)nickel(II)

The synthesis, structural characterization, spectroscopic, and electrochemical properties of N(2)S(2)-ligated Ni(II) complexes, (N,N'-bis(2-mercaptoethyl)-1,5-diazacyclooctane)nickel(II), (bme-daco)Ni(II), and (N,N'-bis(2-mercapto-2-methylpropane)1,5-diazacyclooctane)nickel(II), (bme-daco)Ni(II), derivatized at S with alcohol-containing alkyl functionalities, are described. Reaction of (bme-daco)Ni(II) with 2-iodoethanol afforded isomers, (N,N'-bis(5-hydroxy-3-thiapentyl)-1,5-diazacyclooctane-O,N,N',S,S')halonickel(II) iodide (halo = chloro or iodo), 1, and (N,N'-bis(5-hydroxy-3-thiapentyl)-1,5-diazacyclooctane-N,N',S,S')nickel(II) iodide, 2, which differ in the utilization of binding sites in a potentially hexadentate N(2)S(2)O(2) ligand. Blue complex 1 contains nickel in an octahedral environment of N(2)S(2)OX donors; X is best modeled as Cl. It crystallizes in the monoclinic space group P2(1)/n with a = 12.580(6) ?, b = 12.291(6) ?, c = 13.090(7) ?, beta = 97.36(4) degrees, and Z = 4. In contrast, red complex 2 binds only the N(2)S(2) donor set forming a square planar nickel complex, leaving both -CH(2)CH(2)OH arms dangling; the iodide ions serve strictly as counterions. 2 crystallizes in the orthorhombic space group Pca2(1) with a = 15.822(2) ?, b = 13.171(2) ?, c = 10.0390(10) ?, and Z = 4. Reaction of (bme-daco)Ni(II) with 1,3-dibromo-2-propanol affords another octahedral Ni species with a N(2)S(2)OBr donor set, ((5-hydroxy-3,7-dithianonadiyl)-1,5-diazacyclooctane-O,N,N',S,S')bromonickel(II) bromide, 3. Complex 3 crystallizes in the orthorhombic space group Pca2(1) with a = 15.202(5) ?, b = 7.735(2) ?, c = 15.443(4) ?, and Z = 4. Complex 4.2CH(3)CN was synthesized from the reaction of (bme-daco)Ni(II) with 1,3-dibromo-2-propanol. It crystallizes in the monoclinic space group P2/c with a = 20.348(5) ?, b = 6.5120(1) ?, c = 20.548(5) ?, and Z = 4.     

Protonation and Dehydrogenation During the Multiphoton Ionization of the Cluster: C_4H_5N(H_2O)_n

Proton transfer process in hydrogen-bonded clusters has attracted great interest of many chemists in physical chemistry and biochemistry1-5. Pyrrole (C4H5N) is one of the building blocks of some important biomolecules6. And pyrrole is a compound of five-membered hetero-cyclic aromatic ring, in which a lone pair of electrons offered by the N atom and the two double bonds form a delocalized big ( bond. In this paper we report on the observations for the cluster system pyrrole-water by use of a…     

Quantum wave packet study of N(2D) + H2 reactive scattering

N(²D) + H₂ → NH + H reaction at zero total angular momentum is studied by using a time dependent quantum wave packet method. State‐to‐state and state‐to‐all reactive scattering probabilities for a broad range of energy are calculated. The probabilities show many sharp peaks that ascribed to reactive scattering resonances. The probabilities for J > 0 are estimated by using the J‐shifting method. The integral cross sections and thermal rate constants are then calculated. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006     

Copper(II) complexes of 2-formyl-, 2-acetyl- and 2-benzoyl-pyridine N(4)-phenyl-, N(4)-o-methoxyphenyl-, N(4)-p-methoxy-phenyl- and N(4)-p-nitrophenylthiosemicarbazones

Summary Cu^II complexes of 2-formyl-, 2-acetyl- and 2-benzoylpyridine N(4)-phenyl-, N(4)-o-methoxyphenyl-, N(4)-p-methoxyphenyl- and N(4)-p-nitrophenyltniosemicarbazones, coordinated either as neutral or monoanionic ligands, have been prepared and characterized. I.r., electronic and e.p.r. spectra of the complexes, as well as ¹H-and ¹³C-n.m.r. spectra of the thiosemicarbazones, have been obtained. Both the thiosemicarbazones and their complexes show either modest or no growth inhibitory activity against Paecilomyces variotii. However, some of these thiosemicarbazones possess significant activity against a number of tumour cell strains.     

Infrared spectra of N2O-(ortho-D2)N and N2O-(HD)N clusters trapped in bulk solid parahydrogen

High-resolution infrared spectra of the clusters N2O-(ortho-D2)N and N2O-(HD)N, N=1-4, isolated in bulk solid parahydrogen at liquid helium temperatures are studied in the 2225 cm-1 region of the nu3 antisymmetric stretch of N2O. The clusters form during vapor deposition of separate gas streams of a precooled hydrogen mixture (ortho-D2para-H2 or HDpara-H2) and N2O onto a BaF2 optical substrate held at approximately 2.5 K in a sample-in-vacuum liquid helium cryostat. The cluster spectra reveal the N2O nu3 vibrational frequency shifts to higher energy as a function of N, and the shifts are larger for ortho-D2 compared to HD. These vibrational shifts result from the reduced translational zero-point energy for N2O solvated by the heavier hydrogen isotopomers. These spectra allow the N=0 peak at 2221.634 cm-1, corresponding to the nu3 vibrational frequency of N2O isolated in pure solid parahydrogen, to be assigned. The intensity of the N=0 absorption feature displays a strong temperature dependence, suggesting that significant structural changes occur in the parahydrogen solvation environment of N2O in the 1.8-4.9 K temperature range studied.     

Multiphoton ionization translational spectroscopy (MITS) of I2

A new technique is introduced based on the measurement of kinetic energies and angular distributions of fragments in multiphoton ionization of molecule Both positive and negative ions are measured as well as neutrals. Information is obtained about highly excited repulsive states and about the multiphot ionization process itself. Examples are reported for MPI of I₂. In a one-laser experiment dissociative autoionization is observed. In a two-laser experiment processes are distinguised, that have different intermediate states. Lifetimes of those states are measured. Information is also obtained ab an ion pair formation process, leading to a reinterpretation of potential curves.     

Synthesis of 1D {Cu6(mu3-SC3H6N2)4(mu-SC3H6N2)2(mu-I)2I4}n and 3D {Cu2(mu-SC3H6N2)2(mu-SCN)2}n polymers with 1,3-imidazolidine-2-thione: bond isomerism in polymers

The reaction of copper(I) iodide with 1, 3-imidazolidine-2-thione (SC3H6N2) in a 1:2 molar ratio (M/L) has formed unusual 1D polymers, {Cu6(mu3-SC3H6N2)4(mu-SC3H6N2)2(mu-I)2I4}n (1) and {Cu6(mu3-SC3H6N2)2(mu-SC3H6N2)4(mu-I)4I2}n (1a). A similar reaction with copper(I) bromide has formed a polymer {Cu6(mu3-SC3H6N2)2(mu-SC3H6N2)4(mu-Br)4Br2}n (3a), similar to 1a, along with a dimer, {Cu2(mu-SC3H6N2)2(eta1-SC3H6N2)2Br2} (3). Copper(I) chloride behaved differently, and only an unsymmetrical dimer, {Cu2(mu-SC3H6N2)(eta1-SC3H6N2)3Cl2} (4), was formed. Finally, reactions of copper(I) thiocyanate in 1:1 or 1:2 molar ratios yielded a 3D polymer, {Cu2(mu-SC3H6N2)2(mu-SCN)2}n (2). Crystal data: 1, C9H18Cu3I3N6S3, triclinic, P, a = 9.6646(11) A, b = 10.5520(13) A, c = 12.6177(15) A, alpha = 107.239(2) degrees , beta = 99.844(2) degrees , gamma = 113.682(2) degrees , V = 1061.8(2) A(3), Z = 2, R = 0.0333; 2, C(4)H(6)CuN(3)S(2), monoclinic, P2(1)/c, a = 7.864(3) A, b = 14.328(6) A, c = 6.737(2) A, beta = 100.07(3) degrees , V = 747.4(5), Z = 4, R = 0.0363; 3, C12H24Br2Cu2N8S4, monoclinic, C2/c, a = 19.420(7) A, b = 7.686(3) A, c = 16.706(6) A, beta = 115.844(6) degrees , V = 2244.1(14) A(3), Z = 4, R = 0.0228; 4, C12H24Cl2Cu2N8S4, monoclinic, P2(1)/c, a = 7.4500(6) A, b = 18.4965(15) A, c = 16.2131(14) A, beta = 95.036(2) degrees , V = 2225.5(3) A(3), Z = 4, R = 0.0392. The 3D polymer 2 exhibits 20-membered metallacyclic rings in its structure, while synthesis of linear polymers, 1 and 1a, represents an unusual example of I (1a)-S (1) bond isomerism.     

Copper(II) complexes of 2-formyl-,2-acetyl- and 2-benzoylpyridine N(4)-o-, N(4)-m-, N(4)-p-chlorophenylthiosemicarbazones

Summary Cu^II complexes of 2-formyl, 2-acetyl- and 2-benzoylpyridine N(4)-o-, N(4)-m- and N(4)-p-chlorophenylthiosemicarbazones, coordinated either as a neutral or monoanionic ligand, have been prepared and characterized. I.r., electronic and e.s.r. spectra of the complexes, as well as ¹H- and ¹³C-n.m.r. spectra of the thiosemicarbazones, have been obtained. Both the thiosemicarbazones and their Cu^II complexes show either modest or no growth inhibitory activity against Paecilomyces variotii. Some of the thiosemicarbazones demonstrated significant activity against tumour cell strains.     

Copper(II) complexes of 2-formyl-, 6-methyl-2-formyl- and 2-benzoylpyridine N(4)-(2-methylpyridinyl)-,N(4)-(2-ethylpyridinyl)-and N(4)-methyl(2-ethylpyridinyl)thiosemicarbazones

Summary The title complexes of general formula [Cu(HL)Cl₂] or [Cu(L)Cl] have been isolated and characterized by ¹H and ¹³C-n.m.r., i.r. and electronic spectra. The i.r., electronic and e.s.r. spectral data for the Cu^II complexes are compared with those of previously studied complexes. The antitumour and antiviral activities of the thiosemicarbazones and their complexes are discussed.     

Experimental and theoretical differential cross sections for the N(2D) + H2 reaction

In this paper, we report a combined experimental and theoretical study on the dynamics of the N(2D) + H2 insertion reaction at a collision energy of 15.9 kJ mol(-1). Product angular and velocity distributions have been obtained in crossed beam experiments and simulated by using the results of quantum mechanical (QM) scattering calculations on the accurate ab initio potential energy surface (PES) of Pederson et al. (J. Chem. Phys. 1999, 110, 9091). Since the QM calculations indicate that there is a significant coupling between the product angular and translational energy distributions, such a coupling has been explicitly included in the simulation of the experimental results. The very good agreement between experiment and QM calculations sustains the accuracy of the NH2 ab initio ground state PES. We also take the opportunity to compare the accurate QM differential cross sections with those obtained by two approximate methods, namely, the widely used quasiclassical trajectory calculations and a rigorous statistical method based on the coupled-channel theory.