Synthesis and characterization of octa- and hexanuclear polyoxomolybdate wheels: role of the inorganic template and of the counterion

Eight new compounds based on [O3PCH2PO3]4- ligands and {MoV2O4} dimeric units have been synthesized and structurally characterized. Octanuclear wheels encapsulating various guests have been isolated with different counterions. With NH4+, a single wheel was obtained, as expected, with the planar CO32- guest, (NH4)12[(MoV2O4)4(O3PCH2PO3)4(CO3)2].24H2O (1a), while with the pyramidal SO32- guest, only the syn isomer (NH4)12[(MoV2O4)4(O3PCH2PO3)4(SO3)2].26H2O (2a) was characterized. The corresponding anti isomer was obtained with Na+ as counterions, Na12[(MoV2O4)4(O3PCH2PO3)4(SO3)2]39H2O (2b), and with mixed Na+ and NH4(+) counterions, Na+(NH4)11[(MoV2O4)4(O3PCH2PO3)4(SO3)2].13H2O (2d). With [O3PCH2PO3]4- extra ligands, the octanuclear wheel Li12(NH4)2[(MoV2O4)4(O3PCH2PO3)4(HO3PCH2PO3)2].31H2O (4a) was isolated with Li+ and NH4+ counterions and Li14[(MoV2O4)4(O3PCH2PO3)4(HO3PCH2PO3)2].34H2O (4c) as a pure Li+ salt. A new rectangular anion, formed by connecting two MoV dimers and two MoVI octahedra via methylenediphosphonato ligands with NH4+ as counterions, (NH4)10[(MoV2O4)2(MoVIO3)2(O3PCH2PO3)2(HO3PCH2PO3)2].15H2)O (3a), and Li9(NH4)2Cl[(MoV2O4)2(MoVIO3)2(O3PCH2PO3)2]. 22H2O (3d) as a mixed NH4+ and Li+ salt have also been synthesized. The structural characterization of the compounds, combined with a study of their behavior in solution, investigated by 31P NMR, has allowed a discussion on the influence of the counterions on the structure of the anions and their stability. Density functional theory calculations carried out on both isomers of the [(MoV2O4)4(O3PCH2PO3)4(SO3)2]12- anion (2), either assumed isolated or embedded in a continuum solvent model, suggest that the anti form is favored by approximately 2 kcal mol(-1). Explicit insertion of two solvated counterions in the molecular cavity reverses this energy difference and reduces it to less than 1 kcal mol(-1), therefore accounting for the observed structural versatility.     

Stabilization of reduced molybdenum-iron-sulfur single- and double-cubane clusters by cyanide ligation

Recent work has shown that cyanide ligation increases the redox potentials of Fe(4)S(4) clusters, enabling the isolation of [Fe(4)S(4)(CN)4]4-, the first synthetic Fe(4)S(4) cluster obtained in the all-ferrous oxidation state (Scott, T. A.; Berlinguette, C. P.; Holm, R. H.; Zhou, H.-C. Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 9741). The generality of reduced cluster stabilization has been examined with MoFe(3)S(4) clusters. Reaction of single-cubane [(Tp)MoFe(3)S(4)(PEt(3))3]1+ and edge-bridged double-cubane [(Tp)2Mo(2)Fe(6)S(8)(PEt(3))4] with cyanide in acetonitrile affords [(Tp)MoFe(3)S(4)(CN)3]2- (2) and [(Tp)2Mo(2)Fe(6)S(8)(CN)4]4- (5), respectively. Reduction of 2 with KC(14)H(10) yields [(Tp)MoFe(3)S(4)(CN)3]3- (3). Clusters were isolated in approximately 70-90% yields as Et(4)N+ or Bu(4)N+ salts; clusters 3 and 5 contain all-ferrous cores, and 3 is the first [MoFe(3)S(4)]1+ cluster isolated in substance. The structures of 2 and 3 are very similar; the volume of the reduced cluster core is slightly larger (2.5%), a usual effect upon reduction of cubane-type Fe(4)S(4) and MFe(3)S(4) clusters. Redox potentials and 57Fe isomer shifts of [(Tp)MoFe(3)S(4)L3]2-,3- and [(Tp)2Mo(2)Fe(6)S(8)L(4)]4-,3- clusters with L = CN-, PhS-, halide, and PEt3 are compared. Clusters with pi-donor ligands (L = halide, PhS) exhibit larger isomer shifts and lower (more negative) redox potentials, while pi-acceptor ligands (L = CN, PEt3) induce smaller isomer shifts and higher (less-negative) redox potentials. When the potentials of 3/2 and [(Tp)MoFe(3)S(4)(SPh)3]3-/2- are compared, cyanide stabilizes 3 by 270 mV versus the reduced thiolate cluster, commensurate with the 310 mV stabilization of [Fe(4)S(4)(CN)4]4- versus [Fe(4)S(4)(SPh)4]4- where four ligands differ. These results demonstrate the efficacy of cyanide stabilization of lower cluster oxidation states. (Tp = hydrotris(pyrazolyl)borate(1-)).     

Structural and kinetic study of reversible CO2 fixation by dicopper macrocyclic complexes. From intramolecular binding to self-assembly of molecular boxes

A study of the reversible CO2 fixation by a series of macrocyclic dicopper complexes is described. The dicopper macrocyclic complexes [Cu2(OH)2(Me2p)](CF3SO3)2, 1(CF3SO3)2, and [Cu2(mu-OH)2(Me2m)](CF3SO3)2, 2(CF3SO3)2, (Scheme 1) containing terminally bound and bridging hydroxide ligands, respectively, promote reversible inter- and intramolecular CO2 fixation that results in the formation of the carbonate complexes [{Cu2(Me2p)}2(mu-CO3)2](CF3SO3)4, 4(CF3SO3)4, and [Cu2(mu-CO3)(Me2m)](CF3SO3)2, 5(CF3SO3)2. Under a N2 atmosphere the complexes evolve CO2 and revert to the starting hydroxo complexes 1(CF3SO3)2 and 2(CF3SO3)2, a reaction the rate of which linearly depends on [H2O]. In the presence of water, attempts to crystallize 5(CF3SO3)2 afford [{Cu2(Me2m)(H2O)}2(mu-CO3)2](CF3SO3)4, 6(CF3SO3)4, which appears to rapidly convert to 5(CF3SO3)2 in acetonitrile solution. [Cu2(OH)2(H3m)]2+, 7, which contains a larger macrocyclic ligand, irreversibly reacts with atmospheric CO2 to generate cagelike [{Cu2(H3m)}2(mu-CO3)2](ClO4)4, 8(ClO4)4. However, addition of 1 equiv of HClO4 per Cu generates [Cu2(H3m)(CH3CN)4]4+ (3), and subsequent addition of Et3N under air reassembles 8. The carbonate complexes 4(CF3SO3)4, 5(CF3SO3)2, 6(CF3SO3)4, and 8(ClO4)4 have been characterized in the solid state by X-ray crystallography. This analysis reveals that 4(CF3SO3)4, 6(CF3SO3)4, and 8(ClO4)4 consist of self-assembled molecular boxes containing two macrocyclic dicopper complexes, bridged by CO32- ligands. The bridging mode of the carbonate ligand is anti-anti-mu-eta1:eta1 in 4(CF3SO3)4, anti-anti-mu-eta2:eta1 in 6(CF3SO3)4 and anti-anti-mu-eta2:eta2 in 5(CF3SO3)2 and 8(ClO4)4. Magnetic susceptibility measurements on 4(CF3SO3)4, 6(CF3SO3)4, and 8(ClO4)4 indicate that the carbonate ligands mediate antiferromagnetic coupling between each pair of bridged CuII ions (J = -23.1, -108.3, and -163.4 cm-1, respectively, H = -JS1S2). Detailed kinetic analyses of the reaction between carbon dioxide and the macrocyclic complexes 1(CF3SO3)2 and 2(CF3SO3)2 suggest that it is actually hydrogen carbonate formed in aqueous solution on dissolving CO2 that is responsible for the observed formation of the different carbonate complexes controlled by the binding mode of the hydroxy ligands. This study shows that CO2 fixation can be used as an on/off switch for the reversible self-assembly of supramolecular structures based on macrocyclic dicopper complexes.     

Biotransformation of pinoresinol diglucoside to mammalian lignans by human intestinal microflora,and isolation of Enterococcus faecalis strain PDG-1 responsible for the transformation of (+)-pinoresinol to (+)-lariciresinol

By anaerobic incubation of pinoresinol diglucoside (1) from the bark of Eucommia ulmoides with a fecal suspension of humans, eleven metabolites were formed, and their structures were identified as (+)-pinoresinol (2), (+)-lariciresinol (3), 3'-demethyl-(+)-lariciresinol (4), (-)-secoisolariciresinol (5), (-)-3-(3", 4"-dihydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butane-1, 4-diol (6), 2-(3', 4'-dihydroxybenzyl)-3-(3", 4"-dihydroxybenzyl)butane-1, 4-diol (7), 3-(3"-hydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butane-1, 4-diol (8), 2-(3', 4'-dihydroxybenzyl)-3-(3"-hydroxybenzyl)butane-1, 4-diol (9), (-)-enterodiol (10), (-)-(2R, 3R)-3-(3", 4"-dihydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butyrolactone (11), (-)-(2R, 3R)-2-(3', 4'-dihydroxybenzyl)-3-(3", 4"-dihydroxybenzyl)butyrolactone (12), (-)-(2R, 3R)-3-(3"-hydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butyrolactone (13), 2-(3', 4'-dihydroxybenzyl)-3-(3"-hydroxybenzyl)butyrolactone (14), 2-(3'-hydroxybenzyl)-3-(3", 4"-dihydroxybenzyl)butyrolactone (15) and (-)-(2R, 3R)-enterolactone (16) by various spectroscopic means, including two dimensional (2D)-NMR, mass spectrometry and circular dichroism. A possible metabolic pathway was proposed on the basis of their structures and time course experiments monitored by thin-layer chromatography. Furthermore, a bacterial strain responsible for the transformation of (+)-pinoresinol to (+)-lariciresinol was isolated from a human fecal suspension and identified as Enterococcus faecalis strain PDG-1.     

Structural diversity of lithium sulfenamides: 7Li NMR studies in solution and crystal structures of [Li2(eta2-(CH3)3C-NS-C6H4CH(3)-4)2(THF)2] and [Li2(eta1-4-CH3C6H4-NS-C6H4CH(3)-4)2(THF)4

Two lithium sulfenamides were prepared by reaction of (CH(3))(3)C-N(H)-S-C(6)H(4)CH(3)-4 (1) and 4-CH(3)C(6)H(4)-N(H)-S-C(6)H(4)CH(3)-4 (2) with an alkyllithium. The unsolvated sulfenamide Li[(CH(3))(3)C-NS-C(6)H(4)CH(3)-4] (3) was soluble enough for variable-temperature (VT) (7)Li NMR to provide evidence of a dynamic exchange of oligomers in solution. The crystal structures of the solvated sulfenamides of [Li(2)(eta(2)-(CH(3))(3)C-NS-C(6)H(4)CH(3)-4)(2)(THF)(2)] (4) and of [Li(2)(eta(1)-4-CH(3)C(6)H(4)-NS-C(6)H(4)CH(3)-4)(2)(THF)(4)] (6) consisted of dimers in which the anions display different hapticities. The VT (7)Li NMR spectra of 4 suggest that the two different structures exist in equilibrium in toluene-THF mixtures. These compounds are easily oxidized to the neutral thioaminyl radicals as identified by EPR spectroscopy.     

Heterobimetallic Clusters of Copper(I) with Trithiotungstate and Trithiomolybdate. Synthesis and Characterization of the Octanuclear Clusters [Et(4)N](4)[M(4)Cu(4)S(12)O(4)] (M = Mo, W) and the Dodecanuclear Clusters [M(4)Cu(4)S(12)O(4)(CuTMEN)(4)] (M = Mo, W; TMEN = N,N,N',N'-Tetramethylethylenediamine)

Synthetic methods for [Et(4)N](4)[W(4)Cu(4)S(12)O(4)] (1), [Et(4)N](4)[Mo(4)Cu(4)S(12)O(4)] (2), [W(4)Cu(4)S(12)O(4)(CuTMEN)(4)] (3), and [Mo(4)Cu(4)S(12)O(4)(CuTMEN)(4)] (4) are described. [Et(4)N](2)[MS(4)], [Et(4)N](2)[MS(2)O(2)], Cu(NO(3))(2).3H(2)O, and KBH(4) (or Et(4)NBH(4)) were used as starting materials for the synthesis of 1 and 2. Compounds 3 and 4 were produced by reaction of [Et(4)N](2)[WOS(3)], Cu(NO(3))(2).3H(2)O, and TMEN and by reaction of [Me(4)N](2)[MO(2)O(2)S(8)], Cu(NO(3))(2).3H(2)O, and TMEN, respectively. Crystal structures of compounds 1-4 were determined. Compounds 1 and 2 crystallized in the monoclinic space group C2/c with a = 14.264(5) ?, b = 32.833(8) ?, c = 14.480(3) ?, beta = 118.66(2) degrees, V = 5950.8(5) ?(3), and Z = 4 for 1 and a = 14.288(5) ?, b = 32.937(10) ?, c = 14.490(3) ?, beta = 118.75(2) degrees, V = 5978.4(7) ?(3), and Z = 4 for 2. Compounds 3 and 4 crystallized in the trigonal space group P3(2)21 with a = 13.836(6) ?, c = 29.81(1) ?, V = 4942(4) ?(3), and Z = 3 for 3 and a = 13.756(9) ?, c = 29.80(2) ?, V = 4885(6) ?(3), and Z = 3 for 4. The cluster cores have approximate C(2v) symmetry. The anions of 1 and 2 may be viewed as consisting of two butterfly-type [CuMOS(3)Cu] fragments bridged by two [MOS(3)](2-) groups. Eight metal atoms in the anions are arranged in an approximate square configuration, with a Cu(4)M(4)S(12) ring structure. Compounds 3 and 4 can be considered to consist of one [M(4)Cu(4)S(12)O(4)](4-) (the anions of 1 and 2) unit capped by Cu(TMEN)(+) groups on each M atom; the Cu(TMEN)(+) groups extend alternately up and down around the Cu(4)M(4) square. The electronic spectra of the compounds are dominated by the internal transitions of the [MOS(3)](2-) moiety. (95)Mo NMR spectral data are investigated and compared with those of other compounds.     

4-卤代苯甲酸铽配合物荧光性能的研究

以4-氯苯甲酸(4-ClBA)、4-溴苯甲酸(4-BrBA)和4-碘苯甲酸(4-IBA)为配体合成了三种4-卤代苯甲酸铽的稀土配合物Tb(4-ClBA)3,Tb(4-BrBA)3和Tb(4-IBA)3,紫外可见光吸收光谱表明,相同摩尔浓度的Tb(4-IBA)3的紫外吸收最强,Tb(4-BrBA)3的紫外吸收强度次之,Tb(4-ClBA)3的紫外吸收最弱,而荧光发射光谱表明,Tb(4-IBA)3和Tb(4-BrBA)3的荧光发射强度远小于Tb(4-ClBA)3的.从配体的结构及配体能级、稀土离子Tb3+能级、配体到稀土离子之间的能量传递等角度对该试验结果进行了分析探讨,结果表明苯甲酸对位的碘原子、溴原子和氯原子与苯环上的碳原子所形成的碳卤键热振动的不同是造成三种稀土配合物荧光强度差别较大的本质原因.     

Synthesis and pharmacological evaluation of some 3-(4-methoxyphenyl)-2-substitutedamino-quinazolin-4(3H)-ones as analgesic and anti-inflammatory agents

A variety of novel 3-(4-methoxyphenyl)-2-substitutedamino-quinazolin-4(3H)-ones were synthesized by reacting the amino group of 2-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one with a variety of alkyl and aryl ketones. The starting material 2-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one was synthesized from 4-methoxyaniline. The title compounds were investigated for analgesic, anti-inflammatory and ulcerogenic index activities. While the test compounds exhibited significant activity, compounds 2-(1-methylpropylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A1), 2-(1-ethylpropylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A2) and 2-(1-methylbutylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A3) showed moderately more potent analgesic activity and the compound 2-(1-methylbutylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A3) showed moderately more potent anti-inflammatory activity when compared to the reference standard diclofenac sodium. Interestingly the test compounds showed only mild ulcerogenic potential when compared to aspirin.     

Borohydride, azide, and chloride anions as terminal ligands on Fe/Mo/S clusters. Synthesis, structure and characterization of [(Cl4-cat)(PPr3) MoFe3S4(X)2]2(Bu4N)4 and [(Cl4-cat)(PPr3)MoFe3S4 (PPr3)(X)]2(Bu4N)2 (X = N3-, BH4-, Cl-) double-fused cubanes. NMR reactivity studies of [(Cl4-cat)(PPr3) MoFe3S4(BH4)2]2(Bu4N)4

Our explorations of the reactivity of Fe/Mo/S clusters of some relevance to the FeMoco nitrogenase have led to new double-fused cubane clusters with the Mo2Fe6S8 core as derivatives of the known (Cl4-cat)2Mo2Fe6S8(PPr3)6 (I) fused double cubane. The new clusters have been obtained by substitution reactions of the PPr3 ligands with Cl-, BH4-, and N3-. By careful control of the conditions of these reactions, the clusters [(Cl4-cat)(PPr3)MoFe3S4(BH4)2]2(Bu4N)4 (II), [(Cl4-cat)(PPr3)MoFe3S4(PPr3)(BH4)]2(Bu4N)2 (III), [(Cl4-cat)(PPr3)MoFe3S4(N3)2]2(Bu4N)4 (IV), [(Cl4-cat)(PPr3)MoFe3S4(PPr3)(N3)]2(Bu4N)2 (V), and [(Cl4-cat)(PPr3)MoFe3S4Cl2]2(Et4N)4 (VI) have been obtained and structurally characterized. A study of their electrochemistry shows that the reduction potentials for the derivatives of I are shifted to more positive values than those of I, suggesting a stabilization of the reduced clusters by the anionic ligands BH4- and N3-. Using 1H NMR spectroscopy, we have explored the lability of the BH4- ligand in II in coordinating solvents and its hydridic character, which is apparent in its reactivity toward proton sources such as MeOH or PhOH.     

C-F or C-H bond activation and C-C coupling reactions of fluorinated pyridines at rhodium: synthesis, structure and reactivity of a variety of tetrafluoropyridyl complexes

Reactions of [RhH(PEt3)3] (1) or [RhH(PEt3)4] (2) with pentafluoropyridine or 2,3,5,6-tetrafluoropyridine afford the activation product [Rh(4-C5NF4)(PEt3)3] (3). Treatment of 3 with CO, 13CO or CNtBu effects the formation of trans-[Rh(4-C5NF4)(CO)(PEt3)2] (4a), trans-[Rh(4-C5NF4)(13CO)(PEt3)2] (4b) and trans-[Rh(4-C5NF4)(CNtBu)(PEt3)2] (5). The rhodium(III) compounds trans-[RhI(CH3)(4-C5NF4)(PEt3)2] (6a) and trans-[RhI(13CH3)(4-C5NF4)(PEt3)2] (6b) are accessible on reaction of 3 with CH3I or 13CH3I. In the presence of CO or 13CO these complexes convert into trans-[RhI(CH3)(4-C5NF4)(CO)(PEt3)2] (7a), trans-[RhI(13CH3)(4-C5NF4)(CO)(PEt3)2] (7b) and trans-[RhI(13CH3)(4-C5NF4)(13CO)(PEt3)2] (7c). The trans arrangement of the carbonyl and methyl ligand in 7a-7c has been confirmed by the 13C-13C coupling constant in the 13C NMR spectrum of 7c. A reaction of 4a or 4b with CH3I or 13CH3I yields the acyl compounds trans-[RhI(COCH3)(4-C5NF4)(PEt3)2] (8a) and trans-[RhI(13CO13CH3)(4-C5NF4)(PEt3)2] (8b), respectively. Complex 8a slowly reacts with more CH3I to give [PEt3Me][Rh(I)2(COCH3)(4-C5NF4)(PEt3)](9). On heating a solution of 7a, the complex trans-[RhI(CO)(PEt3)2] (10) and the C-C coupled product 4-methyltetrafluoropyridine (11) have been obtained. Complex 8a also forms 10 at elevated temperatures in the presence of CO together with the new ketone 4-acetyltetrafluoropyridine (12). The structures of the complexes 3, 4a, 5, 6a, 8a and 9 have been determined by X-ray crystallography. 19F-1H HMQC NMR solution spectra of 6a and 8a reveal a close contact of the methyl groups in the phosphine to the methyl or acyl ligand bound at rhodium.     

Mononuclear and dinuclear molybdenum and tungsten complexes of p-tert-butyltetrathiacalix[4]arene and p-tert-butyltetrasulfonylcalix[4]arene: facile cleavage of the calixarene ligand framework by nickel

The reactivity of p-tert-butyltetrathiacalix[4]arene, [S4CalixBut(OH)4], and p-tert-butyltetrasulfonylcalix[4]arene, [(SO2)4CalixBut(OH)4], toward Mo(PMe3)5H2, Mo(PMe3)6, and W(PMe3)4(eta2-CH2PMe2)H has been used to synthesize a series of mononuclear molybdenum and tungsten calixarene compounds that feature both coordinatively saturated and unsaturated metal centers, such as [S4CalixBut(OH)2(O)2]M(PMe3)3H2 (M = Mo, W), [(SO2)4CalixBut(OH)2(O)2]M(PMe3)3H2, [S4CalixBut(OH)2(O)2]Mo(PMe3)3, [(SO2)4CalixBut(OH)2(O)2]Mo(PMe3)3, and [(SO2)4CalixBut(OH)(O)3]M(PMe3)3H. Comparison with the related {[CalixBut(OH)2(O)2]M} complexes indicates that the chemistry of the system is strongly influenced by the nature of the calixarene linker, that is, CH2, S, and SO2. For example, in contrast to the methylene-bridged calixarene system, the thiacalixarene and sulfonylcalixarene systems readily coordinate a second metal center to form homo- and heterodinuclear complexes, namely {[S4CalixBut(O)4]}[M(PMe3)3H2]2, {[(SO2)4CalixBut(O)4]}[Mo(PMe3)3H2]2 and {[S4CalixBut(O)4]}[Mo(PMe3)3H2][W(PMe3)3H2]. Of most interest, incorporation of nickel into [S4CalixBut(OH)2(O)2]M(PMe3)3H2 using Ni(PMe3)4 results in cleavage of a C- bond to give [(SArButOH)(SArButO)3][M(PMe3)3H2][Ni(PMe3)2], an observation that is of relevance to the role that nickel plays in hydrodesulfurization catalysis.     

The elusive vanadate (V(3)O(9))(3-): isolation, crystal structure, and nonaqueous solution behavior.

The isolation, crystal structure, and nonaqueous solution characteristics of the first trinuclear vanadate are presented. The crystal structure reveals a six-membered cyclic arrangement of alternating vanadium and oxygen atoms for the anion of [(C(4)H(9))(4)N](3)(V(3)O(9)). The (51)V NMR spectrum of this compound in CD(3)CN exhibits multiple peaks. The relative intensities of each resonance can be altered by concentration and temperature changes, the later of which are reversible. Addition of [(C(4)H(9))(4)N]Br and NaClO(4) also perturbs the equilibria between species observed. Conductivity data for [(C(4)H(9))(4)N](3)(V(3)O(9)) in CH(3)CN as a function of concentration display pronounced curvature and indicate formation of a neutral species in solution at the highest concentrations studied. Stoichiometric mixtures of [(C(4)H(9))(4)N](3)(V(3)O(9)) with the known vanadates [(C(4)H(9))(4)N](3)(HV(4)O(12)), [(C(4)H(9))(4)N](3)(V(5)O(14)), and [(C(4)H(9))(4)N](3)(H(3)V(10)O(28)) are prepared and examined by (51)V NMR. Equilibration between the various vanadates is observed and characterized. Resonances for these known vanadates, however, cannot be used to identify the peaks found for [(C(4)H(9))(4)N](3)(V(3)O(9)), alone, in solution. The existence of ion pairs in acetonitrile is the only interpretation for the solution behavior of [(C(4)H(9))(4)N](3)(V(3)O(9)) consistent with all data. As such, we can directly observe each possible ion pairing state by (51)V NMR: (V(3)O(9))(3-) at -555 ppm, [[(C(4)H(9))(4)N](V(3)O(9))] (2-) at -569 ppm, [[(C(4)H(9))(4)N](2)(V(3)O(9))](-) at -576 ppm, and [(C(4)H(9))(4)N](3)(V(3)O(9)) at -628 ppm. To the best of our knowledge, [(C(4)H(9))(4)N](3)(V(3)O(9)) presents the first case in which every possible ion paired state can be observed directly from a parent polyion. Isolation and characterization of this simple metal oxo moiety may now facilitate efforts to design functional polyoxometalates.     

Crystallization pathways of sulfate-nitrate-ammonium aerosol particles

Crystallization experiments are conducted for aerosol particles composed of aqueous mixtures of (NH(4))(2)SO(4)(aq) and NH(4)NO(3)(aq), (NH(4))(2)SO(4)(aq) and NH(4)HSO(4)(aq), and NH(4)NO(3)(aq) and NH(4)HSO(4)(aq). Depending on the aqueous composition, crystals of (NH(4))(2)SO(4)(s), (NH(4))(3)H(SO(4))(2)(s), NH(4)HSO(4)(s), NH(4)NO(3)(s), 2NH(4)NO(3) x (NH(4))(2)SO(4)(s), and 3NH(4)NO(3) x (NH(4))(2)SO(4)(s) are formed. Although particles of NH(4)NO(3)(aq) and NH(4)HSO(4)(aq) do not crystallize even at 1% relative humidity, additions of 0.05 mol fraction SO(4)(2-)(aq) or NO(3)(-)(aq) ions promote crystallization, respectively. 2NH(4)NO(3) x (NH(4))(2)SO(4)(s) and (NH(4))(3)H(SO(4))(2)(s) appear to serve as good heterogeneous nuclei for NH(4)NO(3)(s) and NH(4)HSO(4)(s), respectively. 2NH(4)NO(3) x (NH(4))(2)SO(4)(s) crystallizes over a greater range of aqueous compositions than 3NH(4)NO(3) x (NH(4))(2)SO(4)(s). An infrared aerosol spectrum is provided for each solid based upon a linear decomposition analysis of the recorded spectra. Small nonzero residuals occur in the analysis because aerosol spectra depend on particle morphology, which changes slightly across the range of compositions studied. In addition, several of the mixed compositions crystallize with residual aqueous water of up to 5% particle mass. We attribute this water content to enclosed water pockets. The results provide further insights into the nonlinear crystallization pathways of sulfate-nitrate-ammonium aerosol particles.     

Five new nortropane alkaloids and six new amino acids from the fruit of Morus alba LINNE growing in Turkey

Investigation of the constituents of the fruits of Morus alba LINNE (Moraceae) afforded five new nortropane alkaloids (1-5) along with nor-psi-tropine (6) and six new amino acids, morusimic acids A-F (7-12). The structures of the new compounds were determined to be 2alpha,3beta-dihydroxynortropane (1), 2beta,3beta-dihydroxynortropane (2), 2alpha,3beta,6exo-trihydroxynortropane (3), 2alpha,3beta,4alpha-rihydroxynortropane (4), 3beta,6exo-dihydroxynortropane (5), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (7), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid (8), (3R)-3-hydroxy-12-1(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (9), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid (10), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-hydroxymethyl-piperidin-1-yl]-dodecanoic acid-3-O-beta-D-glucopyranoside (11), and (3R)-3-hydroxy-12-[(1R,4S,5S)-4-hydroxy-5-methyl-piperidin-1-yl]-dodecanoic acid (12) on the basis of spectral and chemical data.     

Interpolymetallic assembly of d8-d10 sulfide aggregates from [Pt2(PPh3)4(mu-S)2] and group 12 metals

A series of heterometallic Pt-M (M=Zn and Cd) sulfide aggregates with growing nuclearities (Pt2M), (Pt4M), and (Pt4M2), viz., [ZnPt2Cl2(PPh3)4(mu3-S)2] (2), [CdPt2Cl2(PPh3)4(mu3-S)2] (3), [Pt2(PPh3)4(mu3-S)2]2[ZnSO4]2 (4), [Pt2(PPh3)4(mu3-S)2]2[CdSO4]2.H2O (5), [CdPt4(PPh3)8(mu3-S)4][ClO4]2 (7), and [ZnPt4(PPh3)8(mu3-S)4][ClO4]2 (8), have been prepared from Pt2(PPh3)4(mu-S)2 (1) with appropriate zinc and cadmium substrates. The structures have been determined by single-crystal X-ray diffraction. The supporting anions play an active role in the structural assembly process. An unexpected disintegration complex [Pt2(S2CH2)Cl(PPh3)4][PF6] (6) has also been isolated and characterized by single-crystal X-ray diffraction. The mechanism of the formation of 6 is proposed.     

Synthesis,optical, and spectroscopic characterisation of substituted 3-phenyl-2-arylacrylonitriles

The Knoevenagel condensation between aldehydes and substrates with active methylene groups was applied to synthesise a series of 3-(4-substituted phenyl)-2-arylacrylonitriles (aryl = phenyl or pyridyl). Chloro-, fluoro-, or dimethylamino-substituted aryls and a cyano group attached to the double bond of acrylonitrile were studied. Previous studies showed that the condensation products were E isomers. The compounds synthesised were: 3-(4-chlorophenyl)-2-phenylacrylonitrile, 3-(4-chlorophenyl)-2-(pyridin-2-yl)acrylonitrile, 3-(4-chlorophenyl)-2-(pyridin-3-yl)acrylonitrile, 3-(4-chlorophenyl)-2-(pyridin-4-yl)acrylonitrile, 3-(4-fluorophenyl)-2-phenylacrylonitrile, 3-(4-fluorophenyl)-2-(pyridin-2-yl)acrylonitrile, 3-(4-fluorophenyl)-2-(pyridin-3-yl)acrylonitrile, 3-(4-fluorophenyl)-2-(pyridin-4-yl)acrylonitrile, 3-(4-dimethylaminophenyl)-2-phenylacrylonitrile, 3-(4-dimethylaminophenyl)-2-(pyridin-2-yl)acrylonitrile, 3-(4-dimethylaminophenyl)-2-(pyridin-3-yl)acrylonitrile, and 3-(4-dimethylaminophenyl)-2-(pyridin-4-yl)acrylonitrile. Structures were confirmed by IR, MS, and NMR spectral data. Molar absorption coefficient, absorbance, and fluorescence emission spectra were compared in order to evaluate the effects of substituents on phenyl and the position of nitrogen in pyridine moiety on the electronic properties of acrylonitrile derivatives prepared.     

Mononuclear gold(I) acetylide complexes with urea group: synthesis, characterization, photophysics, and anion sensing properties

A series of mononuclear gold(I) acetylide complexes with urea moiety, R'(3)PAuC≡CC(6)H(4)-4-NHC(O)NHC(6)H(4)-4-R (R' = cyclohexyl, R = NO(2) (2a), CF(3) (2b), Cl (2c), H (2d), CH(3) (2e), (t)Bu (2f), OCH(3) (2g); R' = phenyl, R = NO(2) (3a), OCH(3) (3b); R' = 4-methoxyphenyl, R = H (4a), OCH(3) (4b)), have been synthesized and characterized. The crystal structures of Ph(3)PAuC≡CC(6)H(4)-4-NHC(O)NHC(6)H(4)-4-NO(2) (3a) and (4-CH(3)OC(6)H(4))(3)PAuC≡CC(6)H(4)-4-NHC(O)NHC(6)H(5) (4a) have been determined by X-ray diffraction. Complexes 2a-2g, 3b, and 4a-4b show intense luminescence both in the solid state and in degassed THF solution at 298 K. Anion binding properties of complexes 2a-2g, 3a-3b, and 4a-4b have been studied by UV-vis and (1)H NMR titration experiments. In general, the log K values of 2a-2g with the same anion in THF depend on the substituent R on the acetylide ligand of 2a-2g: R = NO(2) (2a) > CF(3) (2b) ≥ Cl (2c) > H (2d) > CH(3) (2e) ≈ (t)Bu (2f) ≥ OCH(3) (2g). Complex 2a with NO(2) group shows the dramatic color change toward F(-) in DMSO, which provides an access of naked eye detection of F(-).     

Eight-coordinated arsenic in the Zintl phases RbCd4As3 and RbZn4As3: synthesis and structural characterization

Reported are two new series of Zintl phases, ACd(4)Pn(3) and AZn(4)Pn(3) (A = Na, K, Rb, Cs; Pn = As, P), whose structures feature complex atomic arrangements based on four- and eight-coordinated arsenic and phosphorus. A total of 12 compounds have been synthesized from the corresponding elements via high temperature reactions, and their structures have been established by X-ray diffraction. RbCd(4)As(3), KCd(4)As(3), NaCd(4)As(3), NaZn(4)As(3), KCd(4)P(3), and KZn(4)P(3) crystallize with a new rhombohedral structure (space group R3m, Z = 3, Pearson symbol hR24), while the isoelectronic RbZn(4)As(3), CsCd(4)As(3), CsZn(4)As(3), KZn(4)As(3), CsZn(4)P(3), and RbZn(4)P(3) adopt the tetragonal KCu(4)S(3)-type structure (space group P4/mmm, Z = 1, Pearson symbol tP8). Both structures are very closely related to the ubiquitous CaAl(2)Si(2) and ThCr(2)Si(2) structure types, and the corresponding relationships are discussed. The experimental results have been complemented by linear muffin-tin orbital (LMTO) tight-binding band structure calculations. Preliminary transport properties measurements on polycrystalline samples suggest that the compounds of these families could be promising thermoelectric materials.     

Pt(II)-promoted [2 + 3] cycloaddition of azide to cyanopyridines: convenient tool toward heterometallic structures

The [2 + 3] cycloaddition reactions (which are greatly accelerated by microwave irradiation) of the di(azido)platinum(II) compounds cis-[Pt(N(3))(2)(PPh(3))(2)] (1) with cyanopyridines NCR (2) (R = 4-, 3-, and 2-NC(5)H(4)) give the corresponding bis(pyridyltetrazolato) complexes trans-[Pt(N(4)CR)(2)(PPh(3))(2)] (3) [R = 4-NC(5)H(4) (3a), 3-NC(5)H(4) (3b), and 2-NC(5)H(4) (3c)]. Compound 3c has been characterized as the N(1)N(2)-bonded isomer in the solid state by X-ray crystallography and represents the first bis(tetrazolato) complex of this kind. Complexes 3a and 3b have been used as metallaligands to generate heteronuclear coordination polymers in the presence of copper nitrate. A one-dimensional supramolecular architecture was obtained as the exclusive product, {trans-[Pt(2)(N(4)CR)(4)(PPh(3))(4)Cu](n)(NO(3))(2n).nH(2)O (4.nH(2)O) (R = 4-NC(5)H(4)), when 3a was employed, whereas with 3b the heteronuclear square complex trans-[Pt(N(4)CR)(2)(PPh(3))(2)Cu(NO(3))(2)(H(2)O)](2) (5) (R = 3-NC(5)H(4)), composed of Pt/Cu ions, was obtained. All the isolated complexes were characterized by IR, elemental, and (for 3b, 3c, 4, and 5) X-ray structural analyses. Complexes 3 were additionally characterized by (1)H, (13)C, and (31)P {(1)H} NMR spectroscopies.     

Suppression of realgar cage degradation during complexation: formation of hybrid coordination polymers with As4S4, PAs3S3, and Cu(I) halide building blocks

Realgar, As(4)S(4), reacts with Cr(CO)(5)THF under cage degradation to give As(4)S(3)·Cr(CO)(5) (1). The reverse structural change is found if solutions of 1 in CH(2)Cl(2) react with equimolar amounts of PAs(3)S(3)·W(CO)(5) and CuX (X = Cl, Br, I) in CH(3)CN under biphasic diffusion conditions. The resulting coordination polymers 2-4 contain a reconstituted realgar molecule along with the PAs(3)S(3) cage. The crystal structures of (CuX)(As(4)S(4))(PAs(3)S(3)) (X = Cl: 2; Br: 3) are characterized by one-dimensional (1D) (CuX)(As(4)S(4)) strands, which are formed by alternating As(4)S(4) cages and CuX dumbbells. Terminal PAs(3)S(3) molecules are coordinated to copper by apical phosphorus and bridging realgar through sulfur. The As(3) triangles of the resulting (CuX)(As(4)S(4))(PAs(3)S(3)) strands interact with halides of neighbored strands to give a folded three-dimensional (3D) network. The structure of (CuI)(3)(As(4)S(4))(PAs(3)S(3)) (4) contains 1D (Cu(3)I(3))(n) strands as backbones, which are bridged by sulfur atoms of two η(1:2)-As(4)S(4) molecules while PAs(3)S(3) confines the resulting sheet. The As(3) triangles at the surface of the layers interact with iodide of the next layer to form a layered 3D network.