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1.
In the title compound, [Na4(C8H16BO4)4(C4H10O2)]n, there are two coordination types for the four independent Na+ cations: two Na+ cations bond to six diolate O atoms [Na—O = 2.305 (2)–2.609 (2) Å], while the other two are five‐coordinate via one 1,4‐butane­diol [2.289 (2) and 2.349 (3) Å] and four diolate O atoms [2.295 (2)–2.408 (2) Å]. Corresponding to this, there are three‐ and four‐coordinate diolate O atoms, the latter bridging Na atoms. The 1,4‐butane­diol mol­ecules lie on inversion centres. The boron stereochemistry shows minor local perturbations from its usual tetrahedral state [B—O = 1.457 (4)–1.503 (4) Å]. The resulting polymer packs as sheets parallel to the (10) plane crosslinked by the butane­diol mol­ecules. The structure was solved using data from a multiple crystal.  相似文献   

2.
The title compound, {[K(C5H9N2O7P2)(H2O)]·H2O}n, is polymeric and consists of layers parallel to (001) interconnected by hydrogen‐bonding and π–π interactions. The K+ cation is eightfold coordinated in a KO8 environment by O atoms from three different chelating zoledronate units and two coordinated water molecules. The zoledronate group presents its usual zwitterionic character, with negative charges in the singly protonated phosphonate groups and a positive charge at the protonated imidazole N atom. The anion binds to three different K+ cations in a (so far unreported) triply chelating manner. Intra‐ and interplanar interactions are enhanced by a variety of hydrogen bonds involving all available O—H and N—H donors. A strong imidazole–phosphonate C—H...O interaction is present in the structure.  相似文献   

3.
The organic acid–base complex 1,1,3,3‐tetramethylguanidinium 4‐methylbenzenesulfonate, C5H14N3+·C7H7O3S, was obtained from the corresponding 1,1,3,3‐tetramethylguanidinium 4‐methylbenzenesulfinate complex, C5H14N3+·C7H7O2S, by solid‐state oxidation in air. Comparison of the two crystal structures reveals similar packing arrangements in the monoclinic space group P21/c, with centrosymmetric 2:2 tetramers being connected by four strong N—H...O=S hydrogen bonds between the imine N atoms of two 1,1,3,3‐tetramethylguanidinium bases and the O atoms of two acid molecules.  相似文献   

4.
The title compounds, C15H16ClN2O+·Br·1.5H2O and C15H16BrN2O+·Br·1.5H2O, are isomorphous. The benzene ring is oriented nearly normal to the pyridine ring in both compounds. The molecular packing is mainly influenced by intermolecular O—H⋯O and O—H⋯Br interactions, as well as weak intramolecular C—H⋯O interactions. The H2OBr units form an extended water–bromide chain, with a bridging water mol­ecule on a twofold axis.  相似文献   

5.
The analysis of the crystal structures of rac‐3‐benzoyl‐2‐methylpropionic acid, C11H12O3, (I), morpholinium rac‐3‐benzoyl‐2‐methylpropionate monohydrate, C4H10NO+·C11H11O3·H2O, (II), pyridinium [hydrogen bis(rac‐3‐benzoyl‐2‐methylpropionate)], C5H6N+·(H+·2C11H11O3), (III), and pyrrolidinium rac‐3‐benzoyl‐2‐methylpropionate rac‐3‐benzoyl‐2‐methylpropionic acid, C4H10N+·C11H11O3·C11H12O3, (IV), has enabled us to predict and understand the behaviour of these compounds in Yang photocyclization. Molecules containing the Ar—CO—C—C—CH fragment can undergo Yang photocyclization in solvents but they can be photoinert in the crystalline state. In the case of the compounds studied here, the long distances between the O atom of the carbonyl group and the γ‐H atom, and between the C atom of the carbonyl group and the γ‐C atom preclude Yang photocyclization in the crystals. Molecules of (I) are deprotonated in a different manner depending on the kind of organic base used. In the crystal structure of (III), strong centrosymmetric O...H...O hydrogen bonds are observed.  相似文献   

6.
Under Ammonia chemical Ionization conditions the source decompositions of [M + NH4]+ ions formed from epimeric tertiary steroid alchols 14 OHβ, 17OHα or 17 OHβ substituted at position 17 have been studied. They give rise to formation of [M + NH4? H2O]+ dentoed as [MHsH]+, [MsH? H2O]+, [MsH? NH3]+ and [MsH? NH3? H2O]+ ions. Stereochemical effects are observed in the ratios [MsH? H2O]+/[MsH? NH3]+. These effects are significant among metastable ions. In particular, only the [MsH]+ ions produced from trans-diol isomers lose a water molecule. The favoured loss of water can be accounted for by an SN2 mechanism in which the insertion of NH3 gives [MsH]+ with Walden inversion occurring during the ion-molecule reaction between [M + NH4]+ + NH3. The SN1 and SNi pathways have been rejected.  相似文献   

7.
The two title proton‐transfer compounds, 5‐methylimidazolium 3‐carboxy‐4‐hydroxybenzenesulfonate, C4H7N2+·C7H5O6S, (I), and bis(5‐methylimidazolium) 3‐carboxylato‐4‐hydroxybenzenesulfonate, 2C4H7N2+·C7H5O6S2−, (II), are each organized into a three‐dimensional network by a combination of X—H...O (X = O, N or C) hydrogen bonds, and π–π and C—H...π interactions.  相似文献   

8.
Synthesis of Diastereo- and Enantioselectively Deuterated β,ε-, β,β-, β,γ- and γ,γ-Carotenes We describe the synthesis of (1′R, 6′S)-[16′, 16′, 16′-2H3]-β, εcarotene, (1R, 1′R)-[16, 16, 16, 16′, 16′, 16′-2H6]-β, β-carotene, (1′R, 6′S)-[16′, 16′, 16′-2H3]-γ, γ-carotene and (1R, 1′R, 6S, 6′S)-[16, 16, 16, 16′, 16′, 16′-2H6]-γ, γ-carotene by a multistep degradation of (4R, 5S, 10S)-[18, 18, 18-2H3]-didehydroabietane to optically active deuterated β-, ε- and γ-C11-endgroups and subsequent building up according to schemes \documentclass{article}\pagestyle{empty}\begin{document}${\rm C}_{11} \to {\rm C}_{14}^{C_{\mathop {26}\limits_ \to }} \to {\rm C}_{40} $\end{document} and C11 → C14; C14+C12+C14→C40. NMR.- and chiroptical data allow the identification of the geminal methyl groups in all these compounds. The optical activity of all-(E)-[2H6]-β,β-carotene, which is solely due to the isotopically different substituent not directly attached to the chiral centres, is demonstrated by a significant CD.-effect at low temperature. Therefore, if an enzymatic cyclization of [17, 17, 17, 17′, 17′, 17′-2H6]lycopine can be achieved, the steric course of the cyclization step would be derivable from NMR.- and CD.-spectra with very small samples of the isolated cyclic carotenes. A general scheme for the possible course of the cyclization steps is presented.  相似文献   

9.
Semicarbazones can exist in two tautomeric forms. In the solid state, they are found in the keto form. This work presents the synthesis, structures and spectroscopic characterization (IR and NMR spectroscopy) of four such compounds, namely the neutral molecule 4‐phenyl‐1‐[phenyl(pyridin‐2‐yl)methylidene]semicarbazide, C19H16N4O, (I), abbreviated as HBzPyS, and three different hydrated salts, namely the chloride dihydrate, C19H17N4O+·Cl?·2H2O, (II), the nitrate dihydrate, C19H17N4O+·NO3?·2H2O, (III), and the thiocyanate 2.5‐hydrate, C19H17N4O+·SCN?·2.5H2O, (IV), of 2‐[phenyl({[(phenylcarbamoyl)amino]imino})methyl]pyridinium, abbreviated as [H2BzPyS]+·X?·nH2O, with X = Cl? and n = 2 for (II), X = NO3? and n = 2 for (III), and X = SCN? and n = 2.5 for (IV), showing the influence of the anionic form in the intermolecular interactions. Water molecules and counter‐ions (chloride or nitrate) are involved in the formation of a two‐dimensional arrangement by the establishment of hydrogen bonds with the N—H groups of the cation, stabilizing the E isomers in the solid state. The neutral HBzPyS molecule crystallized as the E isomer due to the existence of weak π–π interactions between pairs of molecules. The calculated IR spectrum of the hydrated [H2BzPyS]+ cation is in good agreement with the experimental results.  相似文献   

10.
In the centrosymmetric title polymer, catena‐poly[[bis[aqua­(1,10‐phenanthroline‐κ2N,N′)lead(II)]‐di‐μ3‐5‐carboxy‐3‐sulfonatobenzoato‐1:2:1′κ4O3:O1,O1′:O1;2′:1:2κ4O1:O1,O1′:O3] dihydrate], {[Pb(C8H4O7S)(C12H8N2)(H2O)]·H2O}n, each seven‐coordinate lead(II) ion is bound by five O atoms from one water molecule and three 5‐sulfoisophthalate (sip) anions, and by two N atoms from a 1,10‐phenanthroline (phen) ligand. The sip sulfonate group is monodentate. One O atom of the sip carboxyl­ate group is chelated to one Pb2+ cation, with the other also bridging an adjacent Pb2+ cation. The carboxyl group is uncoordinated. This unusual coordination results in a chain structure along the b axis, which is linked by strong intermolecular hydrogen bonds into a three‐dimensional network.  相似文献   

11.
The title mononuclear CoII complex, [Co(C5H7N6)2(C14H8O5)2(H2O)2]·2H2O, has been synthesized and its crystal structure determined by X‐ray diffraction. The complex crystallizes in the triclinic space group P, with one formula unit per cell (Z = 1 and Z′ = ). It consists of a mononuclear unit with the CoII ion on an inversion centre coordinated by two 2,6‐diamino‐7H‐purin‐1‐ium cations, two 4,4′‐oxydibenzoate anions (in a nonbridging κO‐monodentate coordination mode, which is less common for the anion in its CoII complexes) and two water molecules, defining an octahedral environment around the metal atom. There is a rich assortment of nonbonding interactions, among which a strong N+—H…O bridge, with a short N…O distance of 2.5272 (18) Å, stands out, with the H atom ostensibly displaced away from its expected position at the donor side, towards the acceptor. The complex molecules assemble into a three‐dimensional hydrogen‐bonded network. A variable‐temperature magnetic study between 2 and 300 K reveals an orbital contribution to the magnetic moment and a weak antiferromagnetic interaction between CoII centres as the temperature decreases. The model leads to the following values: A (crystal field strength) = 1.81, λ (spin‐orbit coupling) = −59.9 cm−1, g (Landé factor) = 2.58 and zJ (exchange coupling) = −0.5 cm−1.  相似文献   

12.
What is “Molybdic Acid” or “Polymolybdic Acid”? According to a comparative study of the literature, supplemented by well-aimed experimental investigations and equilibrium calculations, the terms “molybdic acid” or “polymolybdic acid”, used for many substances, species, or solutions in the literature, are applicable to a species, a solution, and two solids:
  • a) The monomeric molybdic acid, most probably having the formula MoO2(OH)2(H2O)2(? H2MoO4, aq), exists in (aqueous) solution only and never exceeds a concentration of ≈ 10?3 M since at higher concentrations it reacts with other monomemeric molybdenum (VI) species to give anionic or cationic polymers.
  • b) A concentrated (>0.1 M MoVI) aqueous molybdate solution of degree of acidification P = 2 (realized, e. g., by a solution of one of the MoVI oxides; by any molybdate solutions whose cations have been exchanged by H3O+ on a cation exchanger; by suitable acidification of a molybdate solution) contains 8 H3O+ and the well-known polyanion Mo36O112(H2O)168? exactly in the stoichiometric proportions.
  • c) A glassy substance, obtained from an alkali metal salt-free solution prepared according to (b), refers to the compound (H3O)8[Mo36O112(H2O)16]·xH2O, x = 25—29.
  • d) A solid having the ideal composition [(H3O)Mo5O15(OH)H2O·H2O]∞ consists of a polymolybdate skeleton (the well-known ?decamolybdate”? structure), in the tunnels of which H3O+ and H2O are intercalate. The structure is very unstable if only H3O+ cations are present, but it is enormously stabilized by a partial exchange of H3O+ by certain alkali or alkaline earth metal cations.
For the compounds MoO3, MoO3·H2O, and MoO3·2H2O the term ?molybdic acid”? is unjustified. The commercial product ?molybdic acid, ≈85% MoO3”? is the well-known polymolybdate (NH4)2O·4 MoO3 with a layer structure of the polyanion.  相似文献   

13.
The crystal structure of 4‐(3‐carboxy‐1‐ethyl‐6‐fluoro‐1,4‐di­hydro‐4‐oxo‐7‐quinolyl)‐1‐methyl­piperazinium methane­sulfonate 0.10‐hydrate, C17H21FN3O3+·CH3O3S?·0.10H2O, contains pefloxacinium cations, methane­sulfonate anions and a partially occupied water of solvation. The quinoline ring system in the cation is essentially planar. The anions lie parallel to each other about inversion centers. The structure is stabilized by strong hydrogen bonds involving the terminal piperazinyl‐N atom of the cation and an O atom of the anion [N?O 2.739 (2) Å], and a strong intramolecular hydrogen bond between carbonyl and carboxyl groups [O?O 2.523 (2) Å].  相似文献   

14.
The title compound, C32H45N2O+·Br?·0.5H2O, has the outer two six‐membered rings in chair conformations, while the central ring is in an 8β,9α‐half‐chair conformation. The five‐mem­bered ring of the steroid nucleus adopts a slightly deformed 14α‐envelope conformation. The pyridyl­methyl­ene moiety has an E configuration with respect to the hydroxyl group at position 17. The structure is stabilized by a network of O—H?Br‐type intermolecular hydrogen bonds.  相似文献   

15.
The title compound, [Nd(C10H16O4)(C10H17O4)(H2O)]n, has a novel Nd–organic framework constructed from sebacic acid (C10H18O4) linkers, the longest aliphatic ligand used to date in lanthanide metal–organic framework compounds. The structure contains edge‐shared chains of NdO8(H2O) tricapped trigonal prisms that propagate in the [100] direction, with Nd—O distances in the range 2.414 (4)–2.643 (4) Å.  相似文献   

16.
The structure of trans‐3‐(3‐pyridyl)acrylic acid, C8H7NO2, (I), possesses a two‐dimensional hydrogen‐bonded array of supramolecular ribbons assembled via heterodimeric synthons between the pyridine and carboxyl groups. This compound is photoreactive in the solid state as a result of close contacts between the double bonds of neighbouring molecules [3.821 (1) Å] along the a axis. The crystal structure of the photoproduct, rctt‐3,3′‐(3,4‐dicarboxycyclobutane‐1,2‐diyl)dipyridinium dichloride, C16H16N2O42+·2Cl, (II), consists of a three‐dimensional hydrogen‐bonded network built from crosslinking of helical chains integrated by self‐assembly of dipyridinium cations and Cl anions via different O—H...Cl, C—H...Cl and N+—H...Cl hydrogen‐bond interactions.  相似文献   

17.
A second polymorphic form (form I) of the previously reported compound {2‐[(2‐hydroxyethyl)iminiomethyl]phenolato‐κO}dioxido{2‐[(2‐oxidoethyl)iminomethyl]phenolato‐κ3O,N,O′}molybdenum(VI) (form II), [Mo(C9H9NO2)O2(C9H11NO2)], is presented. The title structure differs from the previously reported polymorph [Głowiak, Jerzykiewicz, Sobczak & Ziółkowski (2003). Inorg. Chim. Acta, 356 , 387–392] by the fact that the asymmetric unit contains three molecules linked by O—H...O hydrogen bonds. These trimeric units are further linked through O—H...O hydrogen bonds to form a chain parallel to the [11] direction. As in the previous polymorph, each molecule is built up from an MoO22+ cation surrounded by an O,N,O′‐tridentate ligand (OC6H4CH=NCH2CH2O) and weakly coordinated by a second zwitterionic ligand (OC6H4CH=N+HC2H4OH). All complexes are chiral with the absolute configuration at Mo being C or A. The main difference between the two polymorphs results from the alternation of the chirality at Mo within the chain.  相似文献   

18.
The kinetics of the deactivation of O2(1Σg+) is studied in real time. O2(1Σg+) is generated in this system by the O(1D) + O2 reaction following O3laser flash photolysis in the presence of excess O2, and it is monitored by its characteristic emission band at 762 nm. Quenching rate constants were obtained for O2, O3, N2, CO2, H2O, CF4and the rare gases. Since O(1D) is the precursor for the formation of O2(1Σg+), the addition of an O(1D) quencher effectively lowers the initial concentration of O2(1Σg+). By measuring the initial intensity of the 762 nm fluorescence signal, the relative quenching efficiencies were determined for O(1D) quenching by N2, CO2, Xe, and Kr with respect to O2; the results are in good agreement with literature values.  相似文献   

19.
Crystals of bis(2‐ethyl‐3‐hydroxy‐6‐methylpyridinium) succinate–succinic acid (1/1), C8H12NO+·0.5C4H4O42−·0.5C4H6O4, (I), and 2‐ethyl‐3‐hydroxy‐6‐methylpyridinium hydrogen succinate, C8H12NO+·C4H5O4, (II), were obtained by reaction of 2‐ethyl‐6‐methylpyridin‐3‐ol with succinic acid. The succinate anion and succinic acid molecule in (I) are located about centres of inversion. Intermolecular O—H...O, N—H...O and C—H...O hydrogen bonds are responsible for the formation of a three‐dimensional network in the crystal structure of (I) and a two‐dimensional network in the crystal structure of (II). Both structures are additionally stabilized by π–π interactions between symmetry‐related pyridine rings, forming a rod‐like cationic arrangement for (I) and cationic dimers for (II).  相似文献   

20.
In the title compound, [Ni(H2O)6](C17H13O7S)2·8H2O, the NiII atom is located on an inversion centre in the space group P21/c. The [Ni(H2O)6]2+, C17H13O7S and H2O components form many hydrogen bonds and there are π–π stacking inter­actions betweeen the isoflavone units. The hydrogen bonds, π–π stacking inter­actions and electrostatic inter­actions between the cation and anions link the components into a three‐dimensional structure.  相似文献   

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