Discrete and infinite cage-like frameworks with inclusion of anionic and neutral species and with interpenetration phenomena

Complex [Ag(tpba)N(3)] (1) was obtained by reaction of novel tripodal ligand N,N',N"-tris(pyrid-3-ylmethyl)-1,3,5-benzenetricarboxamide (TPBA) with [Ag(NH(3))(2)]N(3). While the reactions between 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (TITMB) and silver(I) salts with different anions and solvent systems give six complexes: [Ag(3)(titmb)(2)](N(3))(3).CH(3)OH.4 H(2)O (2), [Ag(3)(titmb)(2)](CF(3)SO(3))(2)(OH).5 H(2)O (3), [Ag(3)(titmb)(2)][Ag(NO(3))(3)]NO(3).H(2)O (4), [Ag(3)(titmb)(2)(py)](NO(3))(3).H(2)O (py=pyridine) (5), [Ag(3)(titmb)(2)(py)](ClO(4))(3) (6), and [Ag(3)(titmb)(2)](ClO(4))(3).CHCl(3) (7). The structures of these complexes were determined by X-ray crystallography. The results of structural analysis of complexes 1 and 2, with the same azide anion but different ligands, revealed that 1 is a twofold interpenetrated 3D framework with interlocked cage-like moieties, while 2 is a M(3)L(2) type cage-like complex with a methanol molecule inside the cage. Entirely different structure and topology between 1 and 2 indicates that the nature of organic ligands affected the structures of assemblies greatly. While in the cases of complexes 2-7 with flexible tripodal ligand TITMB, they are all discrete M(3)L(2) type cages. The results indicate that the framework of these complexes is predominated by the nature of the organic ligand and geometric need of the metal ions, but not influenced greatly by the anions and solvents. It is interesting that there is a divalent anion [Ag(NO(3))(3)](2-) inside the cage 4 and an anion of ClO(4)(-) or NO(3)(-) spontaneously encapsulated within the cage of complexes 5, 6 and 7.     

Electrophilic amination reactions with 1H-indazole-3-carboxylates: Synthesis of amino acid frameworks and 3-amino-2-oxindoles

Reaction of 1-sulfonylindazole-3-carboxylates with various Grignard reagents effects the N-N bond cleavage of the hydrazone moiety with the first nucleophile and the subsequent N-alkylation gives N,N-dialkylation products in good yields. A new strategy for the synthesis of α-(2-arylsulfonamide)phenylglycine, a precursor to tissue factor/factor VIIa inhibitors is also described. Moreover, the synthesis of quaternary 3-aminooxindoles is developed, utilizing this N,N-dialkylation reaction, followed by intramolecular cyclization/nucleophilic addition reaction.     

Novel 3D, 2D, and 0D first-row coordination compounds with 4,4'-bipyridine-N,N'-dioxide incorporating sulfur-containing anions

The reaction of M(S2O6) (M = Cu(II), Ni(II), and Co(II)) with 4,4'-bipyridine-N,N'-dioxide (bpdo) results in the formation of novel 3D, 2D, and mononuclear complexes. Complex 1, {[Cu(H2O)(bpdo)2](S2O6)(H2O)}n, is a 2-D wavelike polymer with the Cu(II) ion located on a 2-fold axis and having a distorted square-pyramidal coordination sphere. With Co(II) and Ni(II), 3-D complexes, {[M(bpdo)3](S2O6)(C2H5OH)7}n [M = Co(II) (2), Ni(II) (3)], were obtained. The metal atoms are situated on centers of symmetry and have octahedral environments coordinated to six bpdo molecules. The same reaction in aqueous solution with a metal/ligand ratio of 1:1 results in the formation of mononuclear complexes, {[M(bpdo)(H2O)5](SO4)(H2O)2} [M = Co(II) (4), Ni(II) (5)], accompanied by the decomposition of the dithionate anions S2O6(2-) to sulfate anions SO4(2-).     

Rate coefficients for reactions of OH radicals with CH3D,CH2D2, CHD3, and CD4

Fourier transform infrared (FTIR) smog chamber techniques were used to investigate the atmospheric chemistry of the isotopologues of methane. Relative rate measurements were performed to determine the kinetics of the reaction of the isotopologues of methane with OH radicals in cm³ molecule⁻¹ s⁻¹ units: k(CH₃D + OH) = (5.19 ± 0.90) × 10⁻¹⁵, k(CH₂D₂ + OH) = (4.11 ± 0.74) × 10⁻¹⁵, k(CHD₃ + OH) = (2.14 ± 0.43) × 10⁻¹⁵, and k(CD₄ + OH) = (1.17 ± 0.19) × 10⁻¹⁵ in 700 Torr of air diluent at 296 ± 2 K. Using the determined OH rate coefficients, the atmospheric lifetimes for CH_4–xD_x (x = 1–4) were estimated to be 6.1, 7.7, 14.8, and 27.0 years, respectively. The results are discussed in relation to previous measurements of these rate coefficients.     

Hydrothermal single-crystal growth in the systems Ag/Hg/X/O (X = VV, AsV): crystal structures of (Ag3Hg)VO4, (Ag2Hg2)3(VO4)4, and (Ag2Hg2)2(HgO2)(AsO4)2 with the unusual tetrahedral cluster cations (Ag3Hg)3+ and (Ag2Hg2)4+ and crystal structure of AgHgVO4

Single crystals of (Ag3Hg)VO4 (I), (Ag2Hg2)3(VO4)4 (II), AgHgVO4 (III), and (Ag2Hg2)2(HgO2)(AsO4)2 (IV) were grown under hydrothermal conditions (250 degrees C, 5 d) from starting mixtures of elementary mercury, silver nitrate, ammonium vanadate, and disodium hydrogenarsenate, respectively. All crystal structures were determined from X-ray diffraction data, and their chemical compositions were confirmed by electron microprobe analysis. I crystallizes in the tillmannsite structure, whereas II-IV adopt new structure types: (I) I4, Z = 2, a = 7.7095(2) A, c = 4.6714(2) A, 730 structure factors, 24 parameters, R[F2 > 2sigma(F2)] = 0.0365; (II) I42d, Z = 4, a = 12.6295(13) A, c = 12.566(3) A, 1524 structure factors, 55 parameters, R[F2 > 2sigma(F2)] = 0.0508; (III) C2, Z = 4, a = 9.9407(18) A, b = 5.5730(8) A, c = 7.1210(19) A, beta = 94.561(10) degrees , 1129 structure factors, 48 parameters, R[F2 > 2sigma(F2)] = 0.0358; (IV) P31c, Z = 2, a = 6.0261(9) A, c = 21.577(4) A, 1362 structure factors, 52 parameters, R[F2 > 2sigma(F2)] = 0.0477. The most striking structural features of I, II, and IV are the formation of tetrahedral cluster cations (Ag3Hg)3+ and (Ag2Hg2)4+, respectively, built of statistically distributed Ag and Hg atoms with a metal-metal distance of about 2.72 A. The electronic structure of these clusters can formally be considered as two-electron-four-center bonding. The crystal structure of III differs from the protrusive structure types insofar as silver and mercury are located on distinct crystallographic sites without a notable metal-metal interaction >3.55 A. All crystal structures are completed by tetrahedral oxo anions XO4(3-) (X = VV, AsV) and for IV additionally by a mercurate group, HgO2(2-).     

1,2,4‐Triazole Controlled CdII/MnII Complexes with Discrete Mononuclear,Polymeric 1D Chain,and 2D Layer Motifs

Three Htrz‐based metal complexes, [Cd(trz)(CH₃OH)(nb)]_n ( 1 ), [Cd(Htrz)(H₂O)(nb)₂]_n ( 2 ), and {[Mn(Htrz)₂(H₂O)₄] · 2nb} ( 3 ) (Htrz = 1,2,4‐triazole, Hnb = 4‐nitrobenzoic acid), have been synthesized by diffusion or solvent evaporation method and structurally characterized by single crystal X‐ray crystallography, elemental analysis, IR and fluorescence spectroscopy, and TG‐DTA. Structural determinations revealed that complex 1 has a two‐dimensional (2D) layer structure constructed by tridentate μ_N1,N2,N4‐bridging trz anions and Cd^II ions. Complex 2 presents a 1D polymeric chain structure bridged by bidentate μ_N1,N4‐bridging Htrz molecule and Cd^II ions, whereas compound 3 is a supramolecular assembly containing a mononuclear [Mn(Htrz)₂(H₂O)₄]²⁺ dication and two free nb anions for charge compensation. Thus, the structural diversity of the three complexes is significantly governed by the coordination modes of the neutral/deprontated Htrz ligand, rather than the terminal/lattice nb anion. Additionally, the thermal stability of the complexes is observed to be dependent on the polymeric or discrete structure nature. At room temperature, the three solid complexes show Htrz‐based intraligand fluorescent emission.     

A new type of polyhedron-based metal-organic frameworks with interpenetrating cationic and anionic nets demonstrating ion exchange, adsorption and luminescent properties

An interesting new MOF, built with interpenetrating cationic (MOF-A(+)) and anionic (MOF-B(-)) nets that do not require counter ions to balance charge, together with an architectural strategy focused on the use of MOPs as nodes and MOCs as spacers for the generation of 3D frameworks, is reported.     

Synthesis of Fe3O4, Fe2O3, Ag/Fe3O4 and Ag/Fe2O3 nanoparticles and their electrocatalytic properties

Two important iron oxides:Fe3O4 and Fe2O3,as well as Fe3O4 and Fe2O3 nanoparticles mingling with Ag were successfully synthesized via a hydrothermal procedure.The samples were confirmed and characterized by X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The morphology of the samples was observed by transmission electron microscopy(TEM).The results indicated Fe3O4,Fe2O3,Ag/Fe3O4 and Ag/Fe2O3 samples all were nanoparticles with smaller sizes.The samples were modified on a glassy carbon electrode and their elctrocatalytic properties for p-nitrophenol in a basic solution were investigated.The results revealed all the samples showed enhanced catalytic performances by comparison with a bare glassy carbon electrode.Furthermore,p-nitrophenol could be reduced at a lower peak potential or a higher peak current on a glassy carbon electrode modified with Ag/Fe3O4 or Ag/Fe2O3 composite nanoparticles.     

Rational design of 0D, 1D, and 3D open frameworks based on tetranuclear lanthanide(III) sulfonate-phosphonate clusters

Hydrothermal reactions of lanthanide(III) salts with m-sulfophenylphosphonic acid (H3L1) and 1,10-phenanthroline (phen) or N,N'-piperazinebis(methylenephosphonic acid) (H4L2) afforded six novel lanthanide(III) sulfonate-phosphonates based on tetranuclear clusters, namely, [La(2)(L1)2(phen)4(H2O)].4.5H2O (1), [Ln2(L1)2(phen)2(H2O)5].3H2O (Ln = Nd, 2; Eu, 3; Er, 4), and [Ln2(HL1)(H2L2)2(H2O)4].8H2O (Ln = La, 5; Nd, 6). Compounds 2-4 contain discrete tetranuclear lanthanide(III) cluster units in which four lanthanide(III) ions are bridged by two tridentate and two tetradentate phosphonate groups. In compound 1, the tetranuclear clusters are further interconnected into a 1D chain through the coordination of the sulfonate groups. The structures of compounds 5 and 6 can be viewed as a 3D architecture based on a different types of tetranuclear cluster units that are interconnected by bridging H2L2 anions. In the tetranuclear clusters of compounds 5 and 6, the four lanthanide(III) centers are interconnected by only two HL1 ligands. Compound 2 is a luminescent material in the near-IR region, whereas compound 3 displays a strong luminescent emission band in the red-light region. Magnetic property measurements of compounds 2-4 and 6 indicate that there are strong antiferromagetic interactions between magnetic centers within the cluster units.     

Synthesis and reactions of 2, 3-dichlorothianaphthene-1-oxide

Oxidation of 2, 3-dichlorothianaphthene affords 2,3-dichlorothianaphthene-1-oxide. This reacts with methanol, ethanol, and piperidine to give 2-chloro-3-methoxy-, 2-chloro-3-ethoxy-, 2, 3-diethoxy-, and 2-chloro-3-piperidinothianaphthene-1-oxide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1192–1193, September, 1970.     

Synthesis of 3-R-2-aryl-4,6-dinitroindoles and specific features of their reactions with anionic nucleophiles

Reaction of different anionic S-nucleophiles with 3-R-2-aryl-4,6-dinitroindoles led to a regiospecific nucleophilic substitution of the nitro group in position 4 with 6-NO₂ group remaining intact. The representatives of some peri-annulated polycyclic systems were synthesized on the basis of the substitution products. Dedicated to Academician V. A. Tartakovsky in honor of his 75th anniversary. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1543–1547, August, 2007.     

Quantum statistical and wave packet studies of insertion reactions of S(1D) with H2, HD, and D2

A thorough theoretical investigation of the reactions between S(1D) and various hydrogen isotopomers (H2, D2, and HD) has been carried out using a recent ab initio potential energy surface. State-resolved integral and differential cross sections, thermal rate constants, and their dependence on energy or temperature were obtained from quantum mechanical capture probabilities within a statistical model. For comparison, the J=0 reaction probabilities were also computed using an exact wave packet method. The statistical results are in excellent agreement with available exact differential and integral cross sections. The comparison with experimental results shows that the agreement is reasonably good in general, but some significant differences exist, particularly for the SD/SH branching ratio in the S(1D)+HD reaction.     

A series of lanthanide-transition metal frameworks based on 1-, 2-, and 3D metal-organic motifs linked by different 1D copper(I) halide motifs

Hydrothermal reactions of lanthanide(III) oxide and copper halide with isonicotinic acid (Hina) and pyridine-2,3-dicarboxylic acid (H2pdc) or 1,2-benzenedicarboxylic acid (H2bdc) lead to three novel lanthanide(III)-copper(I) heterometallic compounds, namely, [Ce2(ina)5(na)2(H2O)2][Cu5Br4] (1, na=nicotinic acid), [Er4(ina)8(bdc)2(OH)(H2O)5][Cu8I7] (2), and [Ce3(ina)8(bdc)(H2O)4][Cu7Br6] (3). Compound 1 is constructed from two distinct units of the Ln-organic double chains and inorganic [Cu5Br4]nn+ chains. Compound 2 consists of 2D Ln-organic layers and 1D [Cu8I7]nn+ cluster chains. Compound 3 can be viewed as a 1D [Cu6Br6]n chainlike motif inserted into the channels of a 3D Ln-Cu-organic motif. Compounds 1-3 exhibit three different 1D inorganic copper(I)-halide chains interconnected with metal-organic 1D chains, 2D layers, and 3D nets resulting in three mixed-motif non-interpenetrating heterometallic Cu-halide-lanthanide (Ln)-organic frameworks, which represent good examples and a facile method to construct such mixed-motif heterometallic compounds. Furthermore, the IR, TGA, and UV-vis spectra of 1-3 were also studied.     

Kinetics of the reactions of atomic chlorine with H2S,D2S,CH3SH,and CD3SD

Time-resolved resonance fluorescence detection of atomic chlorine following 266-nm laser flash photolysis of Cl₂CO/RSR'/N₂ mixtures has been employed to study the kinetics of Cl reactions with H₂S(k₁), CH₃SH(k₂), D₂S(k₃), and CD₃SD(k₄) as a function of temperature (193–431 K) and pressure (25–600 torr). Arrhenius expressions which describe our results are (units are 10^?11 cm³molecule^?1s^?1; uncertainties are 2σ, precision only) k₁ = (3.69 ± 0.33) exp[(208 ± 24)/T], k₂ = (11.9 ± 1.7) exp[(151 ± 38)/T], and k₃ = (1.93 ± 0.32) exp[(168 ± 42)/T]. The Cl + CD₃SD reaction has been studied at 299 K and 396 K; values for k₄ at these two temperatures are essentially the same as those measured for k₂. Our results are compared with earlier studies and the mechanistic implications of observed negative activation energies and H? D kinetic isotope effects are discussed. © 1995 John Wiley & Sons, Inc.     

Alignment of atoms following photoionisation: Cd+(4d −1 2 D 5/2,2 D 3/2) and Zn+(3d −1 2 D 3/2)

The linear polarisation of fluorescence radiation following the photoionisation in the 4d _5/2 and 4d _3/2 subshells of Cd and in the 3d _3/2 subshell of Zn has been measured in the energy range of primary photons from threshold up to about 40 eV. The experimental values of the linear polarisation found for the fluorescence radiation of Cd⁺(4d ^?1) ions are in essential agreement with theoretical results obtained by an RRPA calculation (Johnson et al.). For the case of Zn⁺(3d ^?1) on the other hand, no theoretical data are presently available. Using the experimental values of linear polarisation of fluorescence radiation the values of the alignment tensorA ₂₀ have been evaluated for the ions Cd⁺(4d ^{?1 2} D _5/2,² D _3/2) and Zn⁺(3d ^{?1 2} D _3/2).     

Total synthesis of maremycins A,B, C1/C2, D1, and D2

The total synthesis of maremycins A, B, C₁/C₂, D₁, and D₂ is achieved starting from the natural amino acids l-isoleucine and S-methyl-l-cysteine, in which the total synthesis of maremycins B, C₁/C₂, and D₂ is accomplished for the first time. The synthesis features a position-selective intramolecular bromination process for the synthesis of key chiral building block, a Pd-catalyzed indole synthesis for the preparation of (2S,3S)-β-methyltryptophan and hydroxylation of oxindoles by molecular oxygen. In addition, the protocol for conversion of maremycins A and B to maremycins C and D was improved.     

2-Halogeno-N-phenacylimidazolium salts and their reactions with active methylene species,arylamines and thiocyanate ions

This study describes the reactivity of 2-halogeno-N-phenacylimidazolium salts towards active methylene species, arylamines and thiocyanate ions. The 2-chloro-N-phenacylimidazolium salt undergoes unexpected reactions in the presence of active methylene species and a tertiary amine as the base. The reaction of 2-bromo-N-phenacylimidazolium salts with arylamines led to a mixture of the corresponding 2-(arylamino)-N-phenacylimidazolium salts and imidazolone. The reaction of 2-bromo-N-phenacylimidazolium bromide with KSCN led to the corresponding imidazole-2-thione. The crystal structures of five compounds are reported.     

Natural radiative lifetimes in the2 S 1/2 and2 D 3/2, 5/2 sequences of neutral copper

Natural radiative lifetimes have been measured of the 3d ¹⁰ ns ² S _1/2 (n=6?10) and of the 3d ¹⁰ nd ² D _{3/2, 5/2} (n=5?9) sequences by using two step excitation of copper atoms in an atomic beam. The states investigated were populated by the light from two pulsed dye lasers pumped by the same Nd:YAG laser. The lifetimes of the² D sequence increase regularly with increasing principal quantum number. This is not the case for the² S series, because of configuration interaction in the² P series. In addition the lifetime of the 3d ¹⁰5p ² P _3/2 state has been measured together with its branching ratio.