The elusive tetrasulfate anion [S4O13](2-)

Sulfates united: the unique tetrasulfate S(4)O(13)(2-) anion was observed in the structure of (NO(2))(2)[S(4)O(13)] that forms in the reaction of N(2)O(5) with SO(3). Theoretical investigations show that the anion is a stable member of the polysulfate series [S(n)O(3n+1)](2-), which was investigated up to n=11.     

[2.2](2,6)Biphenylenophane and [2](2,6)Biphenyleno[2](2,6)naphthalenophane

Two cyclophanes, [2.2](2,6)biphenylenophane and [2](2,6)biphenyleno[2](2,6)naphthalenophane, were prepared.     

[7]- and [6](3,7)tropolonophanes

Synthesis of the titled tropolonophones has been attempted. Though the [7]-compound was obtained, the lower homolog was failed to be synthesized probably because of the strain imposed on the desired compound. The former tropolonophane was shown to exist in the enolone form. PMR and electronic spectra of [7] and [8]-homologs and their methylethers revealed some nonplanarity in the 7-membered rings. PMR spectrum also established the conformation of the bridge in the former compound.     

"Bottom-up" meets "top-down" assembly in nanoscale polyoxometalate clusters: self-assembly of [P4W52O178](24-) and disassembly to [P3W39O134](19-)

The pH-controlled assembly/disassembly of a nanoscale {P4W52O178}24- cluster at pH 2 to a {P4W44O152}20- cluster at pH 3-5 via a {P3W39O134}19- cluster species at pH 2-3 to finally give {P2W19O69(OH2)}14- at pH 6 is reported. This process can be traced in the solid state crystallographically and in solution using dynamic light scattering studies.     

A kinetic and thermodynamic study of the unexpected comproportionation reaction between cis-[Os(VIII)O4(OH)2](2-) and trans-[Os(VI)O2(OH)4](2-) to form a postulated [Os(VII)O3(OH)3](2-) complex anion

A kinetic study of [OsO(4)] reduction by aliphatic alcohols (MeOH and EtOH) was performed in a 2.0 M NaOH matrix at 298.1 K. The rate model that best fitted the UV-VIS data supports a one-step, two electron reduction of Os(VIII) (present as both the [Os(VIII)O(4)(OH)](-) and cis-[Os(VIII)O(4)(OH)(2)](2-) species in a ratio of 0.34:0.66) to form the trans-[Os(VI)O(2)(OH)(4)](2-) species. The formed trans-[Os(VI)O(2)(OH)(4)](2-) species subsequently reacts relatively rapidly with the cis-[Os(VIII)O(4)(OH)(2)](2-) complex anion to form a postulated [Os(VII)O(3)(OH)(3)](2-) species according to: cis-[Os(VIII)O(4)(OH)(2)](2-) + trans-[Os(VI)O(2)(OH)(4)](2-) (k+2) (k-2) 2[Os(VII)O(3)(OH)(3)](2-). The calculated forward, k(+2), and reverse, k(-2), reaction rate constants of this comproportionation reaction are 620.9 ± 14.6 M(-1) s(-1) and 65.7 ± 1.2 M(-1) s(-1) respectively. Interestingly, it was found that the postulated [Os(VII)O(3)(OH)(3)](2-) complex anion does not oxidize MeOH or EtOH. Furthermore, the reduction of Os(VIII) with MeOH or EtOH is first order with respect to the aliphatic alcohol concentration. In order to corroborate the formation of the [Os(VII)O(3)(OH)(3)](2-) species predicted with the rate model simulations, several Os(VIII)/Os(VI) mole fraction and mole ratio titrations were conducted in a 2.0 M NaOH matrix at 298.1 K under equilibrium conditions. These titrations confirmed that the cis-[Os(VIII)O(4)(OH)(2)](2-) and trans-[Os(VI)O(2)(OH)(4)](2-) species react in a 1:1 ratio with a calculated equilibrium constant, K(COM), of 9.3 ± 0.4. The ratio of rate constants k(+2) and k(-2) agrees quantitatively with K(COM), satisfying the principle of detailed balance. In addition, for the first time, the molar extinction coefficient spectrum of the postulated [Os(VII)O(3)(OH)(3)](2-) complex anion is reported.     

The syntheses and conformational studies of [n](2,4)heterophanes and [7](3,5)pyrazolophane

Synthetic sequences from (n + 3)-membered 2-cycloalkenones provide furan, thiophene and pyrrole derivatives bridged at the 2,4-positions by n-methylene chains (n = 6, 7, and 9) as well as a pyrazole derivative bridged at the 3,5-positions (n = 7). The molecular geometry as a function of the chain length has been investigated spectrometrically. The aliphatic chain of [7](2,4)pyrrolophane and [7](3,5)pyrazolophane is found to reside in the one side of the respective heteroaromatic rings even at 205°, whereas that of [7](2,4)thiophenophane flips up and down the thiophene ring upon heating, the energy barrier ΔG_c^≠ being 18·2 kcal/mol (T_c 111°C at 60 MHz). The conformational behaviour of the heptamethylene chain is thus dependent on the angle between the bonds connecting each heteroaromatic carbon with the benzylic one. Though the hexamethylene chain of the [6](2,4)heterophanes is fixed to the one side of the aromatic ring, the nonamethylene chain of the [9]-homologues is rapidly moving between the both sides even at room temperature. The red-shifts of the B-bands are attributed to the distorted, nonplanar heteroaromatic rings. The mass spectra of these heterophanes indicate the initial C(1)-C(2) fission of the polymethylene chain probably due to the steric strain of the systems.     

The synthesis of [9](2,4)pyrrolophanes

Two methods utilized in the synthesis of [9](2,4)pyrrolophanes are reported. The first, an application of the Paal-Knorr cyclization, involved the condensation of ammonia with 3-formylcyclododecanone. The second method employed the condensation of 3-chlorocyclododec-2-en-1-one with diethyl aminomalonate.     

[4](2,7)troponophane

The title compound $\text{5}$ and its dehydro analog $\text{6}$ were synthesized from $\text{10}$ and $\text{9,}$ respectively, and their physical properties were examined. Tropone ring in these compounds are deeply bent to tub shapes and conjugation of the carbonyl group is greatly reduced.     

Ionic liquid-enhanced photooxidation of water using the polyoxometalate anion [P2W18O62](6-) as the sensitizer

Simple polyoxometalate anions are known to be photoreduced in molecular solvents in the presence of 2-propanol or benzyl alcohol. The use of ionic liquids (ILs) as the solvent is now reported to also allow the photooxidation of water to be achieved. In particular, the photochemistry of the classic Dawson polyoxometalate salt K(6)[P(2)W(18)O(62)] has been studied in detail when water is present in the aprotic IL, 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]) and the protic IL, diethanolamine hydrogen sulfate (DEAS). In these and other ILs, irradiation with white light (wavelength 275-750 nm) or UV light (wavelength 275-320 nm) leads to overall reduction of the [P(2)W(18)O(62)](6-) anion to [P(2)W(18)O(62)](7-) and concomitant oxidation of water to dioxygen and protons. The modified structure of bulk water present in ILs appears to facilitate its oxidation. Analogous results were obtained in aqueous solutions containing the protic IL as an electrolyte. The photoproducts (reduced polyoxometalate anion, dioxygen, and protons) were identified by, respectively, voltammetry, a Clark electrode, and monitoring of pH. The formal reversible potentials E(0)(F) for [P(2)W(18)O(62)](6-/7-/8-/9-/10-) couples are much more positive than in molecular solvents. The [P(2)W(18)O(62)](8-) and more reduced anions, if formed as intermediates, would efficiently reduce photoproducts H(+) or dioxygen to produce [P(2)W(18)O(62)](7-), rather than reform to [P(2)W(18)O(62)](6-). Thus, under photoirradiation conditions [P(2)W(18)O(62)](7-) acts as a kinetic sink so that in principle indirect splitting of water to produce dioxygen and dihydrogen can be achieved. The equivalent form of photooxidation does not occur in liquid water or in molecular solvents such as MeCN and MeCN/CH(2)Cl(2) containing added water, but does occur for solid K(6)[P(2)W(18)O(62)] in contact with water vapor.     

Synthesis of the first chiral bidendate bis(trifluoromethyl)phosphane ligand through stabilization of the bis(trifluoromethyl)phosphanide anion in the presence of acetone

Lewis acid/Lewis base adduct formation of the P(CF3)2- ion and acetone leads to a reduced negative hyperconjugation and, therefore, limits the C--F bond activation. The resulting increased thermal stability of the P(CF3)2- ion in the presence of acetone allows selective substitutions and enables the synthesis of the first example of a chiral, bidentate bis(trifluoromethyl)phosphane ligand: a DIOP derivative, [(2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene)]bis(diphenylphosphane), in which the phenyl groups at the phosphorus atoms are replaced by strong electron-withdrawing trifluoromethyl groups. The resulting high electron-acceptor strength of the synthesized bidentate (CF3)2P ligand is demonstrated by a structural and vibrational study of the corresponding tetracarbonyl-molybdenum complex. The stabilization of the P(CF3)2- ion in the presence of acetone is based on the formation of a dynamic Lewis acid/Lewis base couple, (CF3)2PC(CH3)2O-. Although there is no spectroscopic evidence for the formation of the formulated alcoholate ion, the intermediate formation of (CF3)2PC(CH3)2O- could be proved through the reaction with (CF3)2PP(CF3)2, which yields the novel phosphane-phosphinite ligand (CF3)2PC(CH3)2OP(CF3)2. This ligand readily forms square-planar Pt(II) complexes upon treatment with solid PtCl2.     

N-[4-(磺酰胺)苯基](甲基)丙烯酰胺的合成

以对氨基苯磺酰胺、丙烯酰氯(或甲基丙烯酰氯)为原料合成了N-[4-(磺酰胺)苯基]丙烯酰胺(ASPAA)和N-[4-(磺酰胺)苯基]甲基丙烯酰胺(ASPMAA),其结构经^1H NMR,IR和元素分析表征。合成ASPAA的最佳条件：对氨基苯磺酰胺13．76g(80mmol),n(对氨基苯磺酰胺)：n(丙烯酰氯)=1．0：1．1,n(丙烯酰氯)：n(NaHCO3)：1．00：1．14,0℃～2℃反应3h,反应液倾入10倍体积的的甲醇-水[V(甲醇)：V(水)=1：10]中析出产物,收率在60％以上。合成ASPMAA的最佳条件：对氨基苯磺酰胺6．88g(40mmol),n(对氨基苯磺酰胺)：n(甲基丙烯酰氯)=1.00：1．05,n(三己胺)：n(甲基丙烯酰氯)：1．0：1．0,在0℃～2℃滴加甲基丙烯酰氯后先在室温下反应1h,然后在60℃反应1h,反应液倾入700mL石油醚中析出产物,收率50％～60％．     

Transannular interactions insyn- andanti- [2.2](1,4) napthalenophanes andsyn- andanti- [2.2](1,4) anthracenophanes

The UV spectra of the title compounds were interpreted as a result ofPPP-CI-1 calculations of excitation energies and oscillator strengths for the singlet—singlet transitions. A good agreement of the theoretical transitions with the experimental spectrum was found. A strong transannular effect was characteristic for thesyn isomers, the effect decreased in the order:syn-ring anthracenophane,syn-ring naphtalenophane,anti-ring naphthalenophane,anti-ring anthracenophane. Also the influence of a pseudo-substituent effect was found and discussed.     

Oxacalix[n](het)arenes

Oxacalix[n]arenes, reassessed members of the calixarene family in which the traditional methylene bridges are replaced by oxygen atoms, have emerged as a promising class of macrocycles in recent years. This tutorial review summarizes the synthetic progress made in the field during the last few years and aims to stimulate its current evolution from a merely synthetic to a more applied branch of macro- and supramolecular chemistry.