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.     

Isochinoline. 2. Mitteilung [1]. Die Alkoholyse von 1-Chlor-3-chlormethyl-4-methyl-isochinolin und von 1-Chlor-4-chlormethyl-3-methyl-isochinolin

Methanolysis and ethanolysis of 1-chloro-3-chloromethyl-4-methyl-isoquinoline yield respectively 3-methoxymethyl-4-methyl-isocarbostyril and 3-ethoxymethyl-4-methyl-isocarbostyril as main products, together with some 3-chloromethyl-4-methyl-isocarbostyril. By analogous reactions, 1-chloro-4-chloromethyl-3-methyl-isoquinoline yields 4-methoxymethyl-3-methyl-isocarbostyril and 4-ethoxymethyl-3-methyl-isocarbostyril.     

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.     

Reactions of 4-Methoxy-3-quinolinyl and 1,4-Dihydro-4-oxo-3-quino-linyl Sulfides Aiming at the Synthesis of 4-Chloro-3-Quinolinyl Sulfides

The preparation of 1,4-dihydro-4-oxo-3′-alkylthio-3,4′-diquinolinyl sulfides 3 or 1,4-dihydro-4-oxo-3-(alkylthio)quinolines 4 by acid catalysed hydrolysis of 4-methoxy-3′-alkylthio-3,4′-diquinolinyl sulfides 1 or 4-methoxy-3-(alkylthio)-quinolines 2 is described. The reactions of 4-methoxy-3′-alkylthio-3,4′-diquinolinyl sulfides 1 or 1,4-dihydro-4-oxo-3′-alkylthio-3,4′-diquinolinyl sulfides 3 with phosphoryl chloride in DMF afforded 4-chloro-3′-alkylthio-3,4′-diquinolinyl sulfides 5 . Treatment of the title compounds 1 or 3 with boiling phosphoryl chloride systems:leads to 4-chloro-3-(alkylthio)quinolines 6 and thioquinanthrene but those of alkoxy- or oxo-quinolines 2 or 4 lead to 4-chloro-3-(alkylthio)quinolines 6 . The reactions of N-methyl-4(1H)-quinolinones 3n and 4n with phosphoryl chloride directed to 4-chloro-3-(alkylthio)quinolines 6 were studied as well.     

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.     

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 antimicrobial and pharmacological properties of new thiosemicarbazide and 1,2,4‐triazole derivatives

Reaction of 4‐phenyl‐4H‐1,2,4‐triazole‐3‐thione with ethyl bromoacetate has led to the formation of ethyl [(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)sulfanyl]acetate 1 , the structure of which was confirmed by X‐ray analysis. In the next reaction with 80% hydrazide hydrate, appropriate hydrazide 2 was obtained, which in reaction with isothiocyanates was converted to new acyl derivatives of thiosemicarbazides 2 , 3 , 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h . The cyclization of these compounds in alkaline media has led to formation of new derivatives of 5‐{[(4‐phenyl‐4H‐1,2,4‐triazole‐3‐yl)sulfanyl]methyl}‐4H‐1,2,4‐triazole‐3(2H)‐thiones 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4j . The structure of the compounds was confirmed by elementary analysis and IR, ¹H‐NMR, ¹³C‐NMR, and MS spectra. Compounds 2 , 3 , 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h and 4a , 4b , 4c , 4d , 4e , 4f , 4g were screened for their antimicrobial activities, and the influence of the compounds 4a , 4b , and 4e , 4f , 4g on the central nervous system of mice in behavioral tests was examined. J. Heterocyclic Chem., (2011).     

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.     

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.     

锂离子电池复合正极材料xLiFePO4·yLi3V2(PO4)3的复合机制

以FePO4·xH2O、V2O5、NH4H2PO4和Li2CO3为原料, 以乙二酸为还原剂, 通过湿化学还原-低温热处理方法制备出锂离子复合正极材料xLiFePO4·yLi3V2(PO4)3. X射线衍射(XRD)结果表明, 合成的材料中橄榄石结构的LiFePO4和单斜晶系的Li3V2(PO4)3两相共存; 从复合材料中LiFePO4、Li3V2(PO4)3相对于相同条件下制备的纯相LiFePO4和Li3V2(PO4)3的晶格常数变化以及结合高分辨透射电子显微镜(HRTEM)、能量散射X射线(EDAX)的结果可以看出, 在复合材料xLiFePO4·yLi3V2(PO4)3中存在部分V和Fe, 分别掺杂在LiFePO4和Li3V2(PO4)3中, 并形成固溶体; X射线光电子能谱(XPS)结果表明, Fe/V在复合材料中的价态与各自在LiFePO4和Li3V2(PO4)3中的价态保持一致, 分别为+2 和+3价. 充放电测试表明, 制备出的复合正极材料电化学性能明显优于单一的LiFePO4和Li3V2(PO4)3; 循环伏安测试表明, 复合正极材料具有优良的脱/嵌锂性能.     

Tin-oxo clusters based on aryl arsonate anions

Reactions of Ph(3)SnOH or Ph3SnCl with aryl arsonic acids RAsO3H2, where R=C6H5 (1), 2-NH2C6H4 (2), 4-NH2C6H4 (3), 2-NO2C6H4 (4), 3-NO2C6H4 (5), 4-NO2C6H4 (6), 3-NO2-4-OHC6H3 (7), 2-ClC6H4 (8) and 2,4-Cl2C6H3 (9), gave 18 Sn-O cluster compounds. These compounds can be classified into four types: type A: [{(PhSn)3(RAsO3)3(mu3-O)(OH)(R'O)2}2Sn] (R=C6H5, 2-NH2C6H4, 4-NH2C6H4, 2-NO2C6H4, 3-NO2C6H4, 2-ClC6H4, 2,4-Cl2C6H3, and 3-NO2-4-OHC6H3; R'=Me or Et); type B: [{(PhSn)3(RAsO3)(2)(RAsO3H)(mu3-O)(R'O)2}2] (R=4-NO2C6H4, R'=Me); type C: [{(PhSn)3(RAsO3)3(mu3-O)(R'O)3}2Sn] (R=2,4-Cl2C6H3, R'=Me); type D: [{Sn3Cl3(mu3-O)(R'O)3}(2)(RAsO3)4] (R=2-NO2C6H4 and 4-NO2-C6H4; R'=Me or Et). Structures of types A and B contain [Sn3(mu3-O)(mu2-OR')2] building blocks, while in types C and D the stannoxane cores are built from two [Sn3(mu3-O)(mu2-OR')3] building blocks. The reactions proceeded with partial or complete dearylation of the triphenyltin precursor. These various structural forms are realized by subtle changes in the nature of the organotin precursors and aryl arsonic acids. The syntheses, structures, and structural interrelationship of these organostannoxanes are discussed.     

The OsO4F-, OsO4F2(2)-, and OsO3F3- anions, their study by vibrational and NMR spectroscopy and density functional theory calculations, and the X-ray crystal structures of [N(CH3)4][OsO4F] and [N(CH3)4][OsO3F3

The fluoride ion acceptor properties of OsO4 and OsO3F2 were investigated. The salts [N(CH3)4][OsO4F] and [N(CH3)4]2[OsO4F2] were prepared by the reactions of OsO4 with stoichiometric amounts of [N(CH3)4][F] in CH3CN solvent. The salts [N(CH3)4][OsO3F3] and [NO][OsO3F3] were prepared by the reactions of OsO3F2 with a stoichiometric amount of [N(CH3)4][F] in CH3CN solvent and with excess NOF, respectively. The OsO4F- anion was fully structurally characterized in the solid state by vibrational spectroscopy and by a single-crystal X-ray diffraction study of [N(CH3)4][OsO4F]: Abm2, a = 7.017(1) A, b = 11.401(2) A, c = 10.925(2) A, V = 874.1(3) A3, Z = 4, and R = 0.0282 at -50 degrees C. The cis-OsO4F2(2-) anion was characterized in the solid state by vibrational spectroscopy, and previous claims regarding the cis-OsO4F2(2-) anion are shown to be erroneous. The fac-OsO3F3- anion was fully structurally characterized in CH3CN solution by 19F NMR spectroscopy and in the solid state by vibrational spectroscopy of its N(CH3)4+ and NO+ salts and by a single-crystal X-ray diffraction study of [N(CH3)4][OsO3F3]: C2/c, a = 16.347(4) A, b = 13.475(3) A, c = 11.436(3) A, beta = 134.128(4) degrees, V = 1808.1(7) A3, Z = 8, and R = 0.0614 at -117 degrees C. The geometrical parameters and vibrational frequencies of OsO4F-, cis-OsO4F2(2-), monomeric OsO3F2, and fac-OsO3F3- and the fluoride affinities of OsO4 and monomeric OsO3F2 were calculated using density functional theory methods.     

Raman spectra of the double-anion salts M3ZnCl4NO3 (M+ = K+, Rb+, NH4)

Recently characterized K3ZnCl4NO3 and (NH4)3ZnCl4NO3, and newly prepared Rb3ZnCl4NO3 constitute a limited series of isomorphous double-anion salts (space group Pnma, Z = 4). Room-temperature (295 K) Raman spectra from polycrystalline samples of the compounds are reported and interpreted on the basis of the Cs site symmetry of the ZnCl4(2-) and NO3- ions with reference to the D2h factor group of the unit cell. The spectra are compared with Raman spectra of the corresponding M2ZnCl4 and MNO3 single-anion salts. Relative positions and frequencies of the ZnCl4(2-) modes vary considerably among the M3ZnCl4NO3 compounds, despite the isomorphism. The NO3- modes are more similar in all three compounds. The NO3- doubly degenerate v3 and V4 modes are split into two distinct bands as a result of the decent in symmetry from D3h for the free ion to Cs at the crystallographic site. The unequal intensities of the v3 bands observed for K3ZnCl4NO3 and Rb3ZnCl4NO3 and the equal intensities of the v4 bands observed for all three compounds suggest the same factor-group assignments as the high-temperature phase NH4NO3(III). The free-ion Raman-inactive planar deformation mode, v2, is evident in all three compounds, but with lesser intensity than its overtone 2v2. In K3ZnCl4NO3 and Rb3ZnCl4NO3, the symmetric stretching band, in addition to the very strong component for v1, shows a weak, low-frequency band found in many ionic nitrates, which has been attributed to thermally disordered nitrate ions or hot bands. This feature is not found in the spectrum of (NH4)3ZnCl4NO3. The 12 NH4+ ions in the unit cell of (NH4)3ZnCl4NO3, which occupy C1 and Cs sites in a 2:1 ratio, give rise to extremely broad bands that show no evidence of the individual symmetry distinctions of the cations. The broad band from NH4+ v4 obscures the region in which NO3- v3 bands are expected, but the NO3- overtone 2v2 is evident as a sharp peak above a similarly broad band from NH4+ v2.     

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 chemistry of "defect" cyanometalate boxes: (Cs subset [CpCo(CN)3]4[Cp*Ru]3) and (M subset [Cp*Rh(CN)3]4[Cp*Ru]3) (M = NH4, Cs)

A series of heptametallic cyanide cages are described; they represent soluble analogues of defect-containing cyanometalate solid-state polymers. Reaction of 0.75 equiv of [Cp*Ru(NCMe)3]PF6, Et(4)N[Cp*Rh(CN)3], and 0.25 equiv of CsOTf in MeCN solution produced (Cs subset [CpCo(CN)3]4[Cp*Ru]3)(Cs subset Rh4Ru3). 1H and 133Cs NMR measurements show that Cs subset Rh4Ru3 exists as a single Cs isomer. In contrast, (Cs subset [CpCo(CN)3]4[Cp*Ru]3) (Cs subset Co4Ru3), previously lacking crystallographic characterization, adopts both Cs isomers in solution. In situ ESI-MS studies on the synthesis of Cs subset Rh4Ru3 revealed two Cs-containing intermediates, Cs subset Rh2Ru2+ (1239 m/z) and Cs subset Rh3Ru3+ (1791 m/z), which underscore the participation of Cs+ in the mechanism of cage formation. 133Cs NMR shifts for the cages correlated with the number of CN groups bound to Cs+: Cs subset Co4Ru4+ (delta 1 vs delta 34 for CsOTf), Cs subset Rh4Ru3 where Cs+ is surrounded by ten CN ligands (delta 91), Cs subset Co4Ru3, which consists of isomers with 11 and 10 pi-bonded CNs (delta 42 and delta 89, respectively). Although (K subset [Cp*Rh(CN)3]4[Cp*Ru]3) could not be prepared, (NH4 subset [Cp*Rh(CN)3]4[Cp*Ru]3) (NH4 subset Rh4Ru3) forms readily by NH4+-template cage assembly. IR and NMR measurements indicate that NH4+ binding is weak and that the site symmetry is low. CsOTf quantitatively and rapidly converts NH4 subset Rh4Ru3 into Cs subset Rh4Ru3, demonstrating the kinetic advantages of the M7 cages as ion receptors. Crystallographic characterization of CsCo4Ru3 revealed that it crystallizes in the Cs-(exo)1(endo)2 isomer. In addition to the nine mu-CN ligands, two CN(t) ligands are pi-bonded to Cs+. M subset Rh4Ru3 (M = NH4, Cs) crystallizes as the second Cs isomer, that is, (exo)2(endo)1, wherein only one CN(t) ligand interacts with the included cation. The distorted framework of NH4 subset Rh4Ru3 reflects the smaller ionic radius of NH4+. The protons of NH4+ were located crystallographically, allowing precise determination of the novel NH4...CN interaction. A competition experiment between calix[4]arene-bis(benzocrown-6) and NH4 subset Rh4Ru3 reveals NH4 subset Rh4Ru3 has a higher affinity for cesium.     

Design and crystal structures of triple helicates with crystallographic idealized D3 symmetry: the role of side chain effect on crystal packing

Novel crystallographic D3-symmetric binuclear triple molecular helices [Co2L(1)3][BF4]4 (1), [Zn2L(1)3][BF4]4 (2), [Mn2L(1)3][BF4]4 (3), [Co2L(2)3][BF4]4 (4), [Zn2L(2)3][BF4]4 (5), and [Mn2L(2)3][BF4]4 (6) have been achieved to establish the side chain effect on molecular packing, where L1 is [(C5H4N)C(CH3)=N-(C6H4)-]2CH2 and L2 is [(C5H4N)C(CH3)=N-(C6H4)-]2O, respectively. Crystal structure analyses show that each helix crystallizes in a hexagonal crystal system with space group Pc1 and the general axis of the helix occupies the crystallographic 3-fold axial position with the other three crystallographic 2-fold symmetries perpendicular to it. Each metal center is bound to three pyridylimine units to attain C3 pseudooctahedral coordination geometry with respective equivalent metal-N (CH=N) and metal-N (pyridyl) bonds. It is speculated that the existence of the methyl group might minimize the potential intermolecular interactions, which would be the essential factor controlling the helices formed in idealized crystallographic D3 symmetry. Moreover, crystallographic idealized C3-symmetric helicates [Co2L(3)3][BF4]4 (7), [Zn2L(3)3][BF4]4 (8), [Ni2L(3)3][BF4]4 (9), and [Cu2L(3)3][BF4]4 (10) were also structurally characterized for comparison, where L3 is [(C5H4N)C(CH3)=N-]2. All the results indicate that the existence of the methyl group in the side chain of aromatic ligands could effectively reduce the potential - intermolecular interactions and the side chain effect of the methyl group in crystal packing is robust enough to be exchanged from one network structure to another, which ensures the generality and predictability of the crystallographic idealized symmetry formation to a certain extent.     

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.     

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.     

Construction of new heteroselenometallic clusters: formation of crownlike [Et4N]4[(mu5-WSe4)(CuI)5(mu-I)2] and octahedral polymeric [(mu6-WSe4)Cu6I4(py)4]n from planar [Et4N]4[(mu4-WSe4)Cu4I6] with additional faces

The coplanar cluster compound [Et4N]4[(mu4-WSe4)Cu4I6] (1) was prepared from reaction of [Et4N]2[WSe4] with 4 equiv of CuI in N,N-dimethylformamide (DMF) solution in the presence of [Et(4)N]I. Treatment of 1 with pyridine (py) in dry MeCN gave the neutral cluster [(mu4-WSe4)Cu4(py)6I2] (2) in good yield. Recrystallization of 1 from py/i-PrOH resulted in the reorganization of the coplanar WSe4Cu4 core and the formation of a neutral polymeric cluster [(mu3-WOSe3)Cu3(py)3(mu-I)]n (3) containing a nest-shaped OWSe3Cu3 core and a terminal W=O bond. The interaction of cluster 1 with excess PPh3 in CH3Cl3 gave [(mu3-WSe4)Cu3(PPh3)3(mu3-I)] (4) which has a cubanelike SeWSe3Cu3I core. Treatment of 1 with 1 equiv of CuI in dimethyl sulfoxide (DMSO) yielded [Et4N]4[(mu5-WSe4)(CuI)5(mu-I)2] (5) which has a crown-like core structure. Treatment of 1 in DMF with 2 equiv of CuI in the presence of py resulted in the formation of a two-dimensional polymeric cluster, [(mu6-WSe4)Cu6I4(py)4]n (6), consisting of an octahedral WSe4Cu6 repeating unit. The solid-state structures of clusters 3, 5, and 6 have been further established by X-ray crystallography. The nonlinear optical properties of 6 have been also investigated. Cluster 6 was found to exhibit good photostability and a large optical limiting effect with the limiting threshold being ca. 0.3 J cm(-2).     

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.