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The intriguing features of two-dimensional (2D) materials such as better charge carrier separation and abundant surface reaction sites endow them with potential applications as cocatalysts in photocatalysis. In this paper, a ternary 2D nickel hydroxide/sulfides nanosheet composed of Ni(OH)2, Ni3S2 and NixS6 was loaded on CdS nanospheres by a simple chemical deposition route. The composition of nickel hydroxide/sulfides was determined clearly through an overall analysis using X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. Mott-Schottky, electrochemical impedance, steady-state and time-resolved photoluminescence spectroscopy were used to investigate the charge transfer process in CdS and Ni(OH)2/Ni3S2/NixS6-CdS. The results confirm that a synergistic effect of Ni(OH)2/Ni3S2/NixS6 on CdS has occurred under light irradiation, where the Ni(OH)2 and nickel sulfides act as hole storage and surface reaction sites, respectively, to promote the charge transfer on CdS. The improved charge transfer and separation efficiency as well as the increased surface reaction sites in Ni(OH)2/Ni3S2/NixS6-CdS finally result in a dramatically improved photocatalytic performance. The photocatalytic H2 evolution rate of Ni(OH)2/Ni3S2/NixS6-CdS is ca. 46 times higher than that of CdS, and the photocatalytic stability of CdS is also improved substantially under visible light irradiation.

The intriguing features of two-dimensional (2D) materials such as better charge carrier separation and abundant surface reaction sites endow them with potential applications as cocatalysts in photocatalysis. In this paper, a ternary 2D nickel hydroxide/sulfides nanosheet composed of Ni(OH)

It is a challenge to reversibly switch both magnetism and polarity using light irradiation. Herein we report a linear Fe

The well-known rhodamine spiro-lactam framework offers an ideal model for the development of fluorescence-enhanced chemosensors through simple and convenient syntheses. Herein, we report a new tridentate PNO receptor, which was introduced into a rhodamine spiro-lactam system to develop Pd(2+)-chemosensor RPd4, that displayed significantly improved sensing properties for palladium. Compound RPd4 shows a very fast response time (about 5 s), high sensitivity (5 nM), and excellent specificity for Pd(2+) ions over other PGE ions (Pt(2+), Rh(3+), and Ru(3+)). In addition, RPd4 displays quite different responses to different valence states of the Pd ions, that is, very fast response towards Pd(2+) ions but slow response towards Pd(0), which may provide us with a convenient method for the selective discrimination of Pd species in different valence states. According to proof-of-concept experiments, RPd4 has potential applications in Pd(2+)-analysis in drug compounds, water, soil, and leaf samples. Owing to its good reversibility, RPd4 can also be used as a sensor material for the selective detection and visual recovery of trace Pd(2+) ions in environmental samples.

Long-distance f-f interactions: Systematic and comparative studies of the magnetic properties of a series of isostructural sandwich-type tetrakis(phthalocyaninato) diterbium and monoterbium quadruple-decker complexes clearly reveal the suppression of the quantum tunneling of magnetization by the long-distance intramolecular f-f interactions (see figure).

The reactions of methylenediisophthalic acid (H4L) and N-auxiliary ligands (1,2-bis(4-pyridyl)ethylene, 1,2-bis(4-pyridyl)ethane) with transition-metal centers (Co2+/Mn2+) have given rise to four unprecedented polythreading coordination polymers. Single-crystal X-ray diffraction analyses revealed that the compounds can be described as 3D2− ⊂2[1D2+] + 2D6− for 1, 3D4− ⊂1D2+ + 1D6− for 2, and 2D4− ⊂0D2+ + 2[1D3−] for 3 and 4. All the polymers are formed through the assembly of two kinds of motifs with opposite charges. Noncentrosymmetric structures and multifunctionality in 2–4 are established by varying ligands and metal centers. Spontaneous resolution upon crystallization occurred in compounds 3 and 4 in the absence of any chiral source. The enantiomers of 3 and 4 consist of three chiral building blocks of L4−/HL3− and Mn2+ centers. In the solid state, polar compounds 2–4 exhibit nonlinear-optic (NLO) and ferroelectric properties at room temperature. The assembly of two kinds of motifs with opposite charges provides a useful method for the preparation of multifunctional compounds.

The cobalt, nickel, copper, zinc and cadmium complexes of S-methyl-N-(ferrocenyl-1-methyl-methylidene)-dithiocarbazate (H-LSM) and S-benzyl-N-(ferrocenyl-1-methyl-methylidene)-dithiocarbazate (H-LSB) were synthesized and the crystal structure of Cd[Fe-C(CH3) = NNCSS-(CH3)]2 was solved by X-ray diffraction. The crystal is in the orthorhombic system with space group Pbca, cell parameters a=19.741(3), b=19.924(5), c=15.452(4) A, and the final factors of R=0.032. The study on quenching the luminescence of Ru(bpy)2+3 by those complexes showed that bimolecular quenching constants obtained from the Stern-Volmer constant and the excited-state lifetime were related to the redox potential of the quencher. Linear relationship is shown in the plot of logkq vs. E1/2(Q+/Q). The main factor which influences the quenching rate constant and the redox potential is the coordinating ability of the metal in the complex.

A new tetranuclear cobalt(II) molecular square in which adjacent Co(II) centers are linked by a mu(2)-bridging oxygen atom and a N-N bridge along the edges of the square has been designed for single-molecule magnets (SMMs) with high anisotropy barriers. The overall intramolecular ferromagnetic coupling at low temperature combined with the slow relaxation at static zero fields suggests a SMM behavior for this molecular square. The zero-field cooled magnetization (ZFCM) and field cooling magnetization (FCM) at 10 Oe illustrate the nonreversibility and bifurcation below 4.5 K. The deviations of magnetization from the saturated value in strong applied fields demonstrate the participation of low-lying excited states. The peaks of the out-of-phase signals are observed corresponding to coincidence of the applied ac field oscillation frequency with the relaxation rate.

Ten novel metal-organic coordination polymers, [M5(μ3-OH)2(2,3-PDCO)4(H2O)4·xH2O] (2,3-PDCO = pyridine-2,3-dicarboxylic acid N-oxide, M = Mn2+ and x = 3 for 1, M = Co2+ and x = 3 for 3, M = Cd2+ and x = 1.5 for 10), [Mn(2,3-PDCO)(4,4′-bpy)(H2O)2] (2), [M2(2,3-PDCO)2(4,4′-bpy)(H2O)2·xH2O] (M = Co2+ and x = 1 for 4, M = Zn2+ and x = 0 for 7), [M(2,3-PDCO)(L)·H2O] (M = Co2+ and L = bbix (1,4-bis(benzimidazol-1-ylmethyl)-benzene) for 5, M = Zn2+ and L = bix (1,4-bis(imidazol-1-ylmethyl)-benzene) for 8), [Cu(2,3-PDCO)(4,4′-bpy)·H2O] (6), [Zn2(2,3-PDCO)2(bbi)] (bbi = 1,1′-(1,4-butanediyl)bis(imidazole)) (9), were obtained under hydrothermal conditions and characterized structurally. The networks exhibit a variety of topologies and coordination modes at the metal centers. 1, 3, and 10 are isostructural and possess three-dimensional (3D) frameworks with penta-nuclear metal clusters as secondary building units (SBU). 5 and 7 individually exhibit a one-dimensional (1D) infinite chain and two-dimensional (2D) rectan...

Two closed-shell d 10 metal ions complexes Cd 2 (L) 2 (I) 4 (1) and Zn 2 (L) 2 (Cl) 4 (DMF) 2 (2) were prepared from molecular clips, 2,2′-bis(benimidazol-1-ylmethyl)-biphenyl (L), and structurally characterized to investigate the structures. Both compounds 1 and 2 are bimetallic supramolecular rectangles in which two L ligands are connected by two tetrahedral coordinated metal ions. These units are connected together through weak π π interaction, and 1 and 2 are crystallized in P2(1)/c and P-1 space group, respectively. Solid state fluorescent measurements exhibit the presence of ligand-based emission at 407 and 370 nm of compounds 1 and 2, respectively.

The self-assembly and structural characterization of the new manganese(II) [MnL 2](ClO4)2(CH3OH)0.5 (1) complex has been achieved. The crystallographic data for the complex 1: Orthorhombic Pbca , a = 16.287(2) A, b = 21.293(2)A, c = 32.718(3) A, V = 11,347(2) A3, Z = 8. The two polydentate ligands strand intertwined each other and around the manganese(II) ions forming a mononuclear complex. The Mn(II) ion is eight-coordinated with the eight donor nitrogen atoms of two ligands to form a distorted square antiprismatic coordination geometry. The magnetic properties investigation indicates that there is a weak antiferromagnetic exchange coupling between the Mn(II) ions of the complex. An octa-coordinated Mn(II) complex which exhibits a distorted square antiprismatic coordination geometry has been achieved by using a bisbidentate Schiff-base ligand.

Three ligands with flexible bis-terdentate coordination sites, di(2-pyridylcarbaldehyde)-6,6′-dicarboxylic acid hydrazone-2,2′-bipyridine ( H 2 L 1 ), di(2-acetylpyridyl)-6,6′-dicarboxylic acid hydrazone-2,2′-bipyridine ( H 2 L 2 ) and di(2-pyridylketone)-6,6′-dicarboxylic acid hydrazone-2,2′-bipyridine ( H 2 L 3 ) have been easily prepared. Dinuclear double-stranded helicates Co 2 ( L 1 ) 2 (ClO 4 ) 2 (C 2 H 5 OH) 2 (H 2 O) 2 ( 1 ), Co 2 ( HL 2 )( L 2 )(ClO 4 ) 3 (C 2 H 5 OH) 2 (H 2 O) 2 ( 2 ) and Co 2 ( HL 3 )( L 3 )(ClO 4 ) 3 (H 2 O) 4 ( 3 ) based on the ligands, H 2 L 1 – 3 , respectively, have been obtained via self-assembly, their structures were determined by FT-IR, Elemental Analysis, ESI-MS and X-ray diffraction method.

A coordination polymer [Ag4(C12H12N6)3](ClO4)4(H2O)4 (1), was achieved via the self-assembly of AgClO4 with ligand 2,5-bis(pyrazinyl)-3,4-diaza-2,4-hexadiene (L1). The structure of compound 1 is a 3D metal–organic framework that consists of the circular helicate Ag3 (L1)3 secondary building blocks (SBUs). Each Ag 3 L 3 1 is capped at its every exo-monodentate pyrazinyl terminal by the unusual hexa-coordinated Ag(I) centers. Being filled within the cavities, the ClO 4 - anions could be exchanged reversibly with PF 6 - in the solid state.

Three silver complexes Ag 2 (L) 2 (NO 3 ) 2 ( 1 ), Ag 2 (L) 2 (SO 3 CF 3 ) 2 (H 2 O) 0.5 ( 2 ), and [Ag 2 (L) 2 (NO 3 ) 2 ] n ( 3 ) were prepared from molecular clips, 2,2′-Bis(imidazol-1-ylmethyl)-biphenyl ( L ) and structurally characterized to investigate the structural-luminescent relation. Compound 1 is a bimetallic supramolecular rectangle in which two L ligands are connected by two linearly coordinated Ag(I) ions. Compound 2 is described as a double helicate due to the nature of the twist of the imidazole groups after coordination to Ag(I) centers. In compound 3 , the Ag(I) centers are connected by L ligands into a one-dimensional zigzag chain. Solid state and solution fluorescent measurements exhibit the presence of ligand-based emission at 415 and 435 nm of compounds 1 and 2 , respectively. It is said that the dihedral angles between the two imidazole rings coordinated to one Ag(I) center affect the emission properties.

The hydrothermal assembly of CoCl2 · H2O with benzene-1, 2, 3, 4-tetracarboxylic acid (H4mpda) yielded a novel lamellar coordination polymeric complex, Co2mpda(H2O)6 · H2O (1), in which each layer presents an interesting multifold topology: both as partially overlapped helices with alternate chirality and as alternately arranged ladders and zigzag chains.

A highly selective fluorogenic signaling fluoride-sensor Ru-HL, comprised of Ru-bipy moiety (bipy = 2,2′-bipyridine) and 3-hydroxyl-2-naphthoylhydrazine was prepared and structurally characterized. The fluorescence spectra titration revealed the high selectivity and sensitivity of Ru-HL for F− through an excited-state intermolecular proton transfer (ESPT) signaling transduction mechanism.

The solution-phase reactions of metal iodides or iodine with 1,3-bis(4-pyridyl)propane (bpp) yields four new organic–inorganic hybrid frameworks, namely [(CuI)4(bpp)4]n(1), [(AgI)6(bpp)]n (2), [PbI2(bpp)]n (3), and [I3(bppH)] (4), each of which adopts a different structural motif. For example, complex 1 is a 2D “open” coordination polymeric cluster consisting of a CuI2Cu rhomboid cluster core coordinated by anti-anti and anti-gauche bpp interactions to produce an interpenetrating 2D (4,4) polycatenane net; 2 is a novel bpp inclusion compound with a unique 2D polymeric hexagonal prism-shaped [Ag6I6]n cluster motif; compound 3 is also a 2D “open” supramolecular cluster made from [PbI2]n “ribbons” and bpp bridges; compound 4 is a triiodide made up of organic [bppH]+ cations and a I3– anion chain. The clusters 1–3 obtained from the reaction between polyiodide complexes and an organic ligand suggest that this simple synthetic approach is likely to be applicable to the construction of polymeric clusters. The third-order NLO effects of 1 were studied by Z-scan techniques. The polymeric cluster exhibits good nonlinearities and the effective third-order NLO refractive index (n2) value is 2.56 × 10–12 esu which is comparable to those of most cluster monomers and polymers. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Benzene-based bipodal and tripodal electrochemical-responsive receptors with ferrocenyl arms comprising benzoimidazolium moieties were synthesized and structurally characterized. The two-arm para compound 1·2Br exhibited a cisoid conformation with the two ferrocene moieties positioned in the same side and a templating bromide anion sited inside. The cisoid form was stabilized not only by the (C–H)+⋯Br− hydrogen bond, but also cooperated by the C–H⋯Br− hydrogen bonding related to the Cp rings of the ferrocenyl moieties and the CH2 groups, respectively. The association constants of the receptor 1 for Cl−, Br− and I− were determined using 1H NMR titration in d6-DMSO as 600 M−1, 440 M−1 and 350 M−1, respectively. The meta three-arm compound 2·3Br adopted a cone conformation with a bromide anion sited inside the molecular cavity and three ferrocene-containing arms positioned on the same side. The cationic heterocycle interacted with the bromide anion through the three-fold C–H⋯Br− hydrogen bonding. 1H NMR titrations in d6 DMSO revealed that the association constants of 2 for Cl−, Br− and I− were 9.7 × 103 M−1, 6.8 × 103 M−1 and 120 M−1, respectively. Electrochemical measurements demonstrated that directed hydrogen bonding between the ferrocenyl moiety and the anion was important for the two-arm receptor 1 exhibiting more efficient binding electrochemical signal transduction.

One-dimensional copper(II) polymers [(Cu 4 L 2 )(NO 3 ) 4 ] n ( 1 ) and [(Cu 4 L 2 )Cl 4 ] n ( 2 ) (H 2 L = salicylaldehyde-2-pyridinecarboxyl-hydrazone) were achieved via self-assembly. The Cu⋯Cu separations were ca. 2.90 and 4.75 A for the phenoxide oxygen bridged pair and the N–N bridged pair with antiferromagnetic spin exchanges between Cu(II) ions.

Four novel interesting cadmium(II) or zinc(II) metal coordination polymers, [Cd2(2,3-pydc)2(bix)3·2H2O]n (1), [Cd2(μ2-OH2)(2,6-pydc)2(bix)]n (2), [Cd3(SIP)2(bix)4·8H2O]n (3), and [Zn2(SIP)(bix)3(OH)·2H2O]n (4) (bix = 1,4-bis(imidazol-1-ylmethyl)-benzene; 2,3-pydc = pyridine-2,3-dicarboxylic acid; 2,6-pydc = pyridine-2,6-dicarboxylic acid; SIP = 5-sulfoisophthalic acid monosodium salt), have been synthesized under hydrothermal conditions and structurally characterized. Polymer 1 features a 3D porous framework with uncoordinated water molecules trapped in the pores. Polymer 2 is a 2D infinite layer framework, and the resulting 2D structure is interconnected by hydrogen-bond interactions to lead to a 3D supramolecular architecture. Polymer 3 also possesses a 3D porous framework; the most prominent cavities are parallel to the a- and b- directions and are filled with free water molecules. Polymer 4 exhibits 4-fold interpenetration related by three different translation vectors. These four compounds exhibit st...

A six-coordinated Ru(II) complex of [(bpy)2Ru(S,O-H2L)] · 1.5CH3CN, where H4L is a p-tert-butyltetrathiacalix[4]arene, was synthesized and characterized by electrospray ionization mass spectrometry and X-ray crystallographic analysis. Fluorescence quenching of ethidium bromide–DNA complex by the Ru(II) complex obeys linear Stern–Volmer equation. The quenching was realized via the DNA-mediated electron transfer from the excited ethidium to the Ru(II) complex.

Five novel interesting d(10) metal coordination polymers, [Zn(PDCO)(H2O)2]n (PDCO = pyridine-2,6-dicarboxylic acid N-oxide) (1), [Zn2(PDCO)2(4,4'-bpy)2(H2O)2.3H2O]n (bpy = bipyridine) (2), [Zn(PDCO)(bix)]n (bix = 1,4-bis(imidazol-1-ylmethyl)benzene) (3), [Zn(PDCO)(bbi).0.5H2O]n (bbi = 1,1'-(1,4-butanediyl)bis(imidazole)) (4), and [Cd(PDCO)(bix)(1.5).1.5H2O]n (5), have been synthesized under hydrothermal conditions and structurally characterized. Polymer 1 possesses a one-dimensional (1D) helical chainlike structure with 4(1) helices running along the c-axis with a pitch of 10.090 Angstroms. Polymer 2 has an infinite chiral two-dimensional (2D) brick-wall-like layer structure in the ac plane built from achiral components, while both 3 and 4 exhibit an infinite 2D herringbone architecture, respectively extended in the ac and ab plane. Polymer 5 features a most remarkable and unique three-dimensional (3D) porous framework with 2-fold interpenetration related by symmetry, which contains channels in the b and c directions, both distributed in a rectangular grid fashion. Compounds 1-5, with systematic variation in dimensionality from 1D to 2D to 3D, are the first examples of d(10) metal coordination polymers into which pyridinedicarboxylic acid N-oxide has been introduced. In addition, polymers 1, 4, and 5 display strong blue fluorescent emissions in the solid state. Polymer 3 exhibits a strong SHG response, estimated to be approximately 0.9 times that of urea.

The reaction of Ru(DMSO)4Cl2 and N,N'-bis[1-(pyridin-2-yl)ethylidene]benzidine (L) in the presence of NaClO4 afforded the tetranuclear ruthenium compound, Ru4L6·10ClO4, by self-assembly. Magnetic and electrochemical measurements clearly indicated the presence of both RuII and RuIII moieties within the tetrahedral ruthenium cluster. The Robin-Day Class II mixed-valence behavior was supported by the UV/Vis-NIR spectra with the electronic coupling parameter Vab of 200 cm–1. It is demonstrated that the mixed-valenceRuII2RuIII2L6 cation was stabilized by controlling the coordination geometries of the ruthenium ions between octahedral and trigonal prismatic to fit the supramolecular structure of the tetranuclear cluster. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Heteropolynuclear organometallic compounds have been constructed by using the ferrocene-based ligand H(2)L, [NH(2)SCNHN=C(CH(3))(C(5)H(4))](2)Fe. Reaction of the ligand H(2)L with the cobalt(II) salt gave a tetranuclear helicate Co(2)Fe(2) (1) with two ferrocene-based clips wrapped around the two cobalt atoms. The chiral helicates recognized the neighbors with same chirality through intermolecular hydrogen bonding between the thiosemicarbazone moieties to form a one-dimensional chiral channel. Reaction of the ligand H(2)L with the cadmium(II) salt afforded a tetranuclear dimeric compound Cd(2)Fe(2) (2), with two symmetric related parts bridged through two sulfur atoms. Reaction of the ligand H(2)L with the copper(I) salt, in the presence of triethylamine, resulted in a hexanuclear compound Cu(4)Fe(2) (3) with a crownlike Cu(4)S(4) octagon similar to that of S(8) sited inside and two ferrocene-containing ligands positioned outside. Electrochemical measurements were displayed to investigate the redox communications between the ferrocene moieties through metal centers.

Three new ligands, 1-(benzimidazolyl-2-methyl)-1,4,7-triazacyclononane L1, 1,4-bis(benzimidazolyl-2-methyl)-1,4,7-triazacyclonone L2, and 1,4,7-tris-(benzimidazolyl-2-methyl)-1,4,7-triazacyclonane L3, were synthesized by a straightforward one-pot method. Their nickel(II) complexes [ Ni 2 L 2 1 Cl 2 ] · ( ClO 4 ) 2 , [NiL2CH3CN](ClO4)2 · 2CH3OH · H2O (or [NiL2Cl] · ClO4) and [Ni(H−2L3)] · H2O were obtained and characterized by electrospray mass spectrum, 1H NMR, CV and other physical methods. Their crystal structures were determined by X-ray analyses. The crystal structure of the nickel(II) complex of L1 shows that two Ni(II) atoms are bridged by two Cl− anions. A ferromagnetic exchange coupling and zero-field splitting effect exist in complex 1.

The novel heteronuclear complexes [M(CuL)2]2 · nH2O [M = Ba (1), Ca (2); H2L = N-salicylideneglycylglycine] were synthesized and characterized, and the crystal structure of complex (1) was determined by X-ray diffraction. The entire structure is held together by an extensive network of H-bonds and π–π interactions. Variable-temperature magnetic susceptibility measurements (75–300 K) revealed the occurrence of an intramolecular antiferromagnetic interaction in (1) and (2).

A novel bridged organocobaloxime-bromo(O-trimethylene-CHEL)cobaloxime was synthesized by heating the Aqua(3-bromopropyl)cobaloxime at 50 °C in methanol/H2O and crystal structure was determined by X-ray diffraction analysis.

A new dicopper(II) complex with 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)-tricyclo[22,2,2,211,14]triaconta-1,11,13,24,27,29-hexaene(L), was synthesized and characterized. The crystal structure of [Cu2L(N3)2](ClO4)2·2H2O has shown that both Cu2+ ions are in penta-coordination environment with distorted trigonal bipyramid consisting of three N atoms from diethylenetriamine moieties, one N atom from azide and one O atom from hydroxyethyl pendant, and the separation of Cu⋯Cu is 8.11 A. The two aromatic rings are close to each other, the shortest distance being 3.71 A for C11⋯C21, and the benzene ring planes from a dihedral angle of 70.9° in molecule. ES-MS spectra showed that the main species, [Cu2(L–H)N3]2+ and [Cu2(L–2H)]2+, were formed by deprotonation of the hydroxyethyl pendants and releasing azides from the Cu(II) complex stepwise.

A novel saddle-form macrocyclic barium complex was synthesized by cyclo-condensation of diformylpyridine with [BaL1(ClO4)2]·3H2O. In the complex crystal [BaL2(ClO4)2(H2O)]·MeOH·1.5H2O, two perchlorate anions are cis-coordinated to barium(II), and the coordinated water molecule is located on the opposite side to the perchlorate anion. 1H NMR and ES MS spectra were used to characterize its structure in methanol solution. The mechanism of the reaction was discussed.

A new dinuclear manganese (III) complex [(ac)Mn(bbml) 2 Mn(ac)]·(BF 4 ) 2 ·3.5H 2 O (Hbbml=[bis(2-benzimidazolylmethyl)amino]ethanol, Hac=acetic acid) was synthesized and characterized by several physical methods. X-ray structure analysis shows that the complex has a dimeric unit and the two Mn(III) atoms are bridged by the oxygen atoms of the two ligands, forming a bis (μ-alkoxo)dimanganese core. The Mn–Mn distance is 3.2103 A. Electrospray mass spectrometry (ES-MS) experiment shows that the complex cation may easily have lost one or two ac − and leave unoccupied coordination site which would favor the coordination and activation of hydrogen peroxide. Furthermore, its catalytic activity for the disproportionation of hydrogen peroxide and the effect of added heterocyclic base were also investigated. The complex has some similarities to manganese catalase in structure and activity.

The title binuclear Mn2(III) complex was synthesized through the reaction of 2-[bis(2-benzimidazolylmethyl)amino]ethanol (Hbbml), Mn(DMSO)6(ClO4)3 and o-toluic acid (Htol). X-ray structure analysis shows that the two Mn(III) atoms are bridged by the oxygen atoms of the two bbml ligands, forming a bis(μ-alkoxo)dimanganese core. Electrospray mass spectrometry (ES-MS) experiments shows that the complex cation may easily lose one or two tol− ligands leaving an unoccupied coordination site, which would favor the coordination and activation of H2O2. Furthermore, its catalytic activity for the disproportionation of H2O2 and the effect of added heterocyclic base were also investigated. The complex has some similarities to manganese catalase in structure and activity.

The preparation of the heteropolyoxometalates K6[HPMo5V7O40(VO)]·16H2O (1), (n-Bu4N)4[H3PMo5V7O40(VO)] (2) and (CN3H6)6[HPMo5V7O40(VO)]·4H2O (3) is described. Compounds 2 and 3 have been characterized by X-ray diffraction methods. Both compounds contain a monocapped Keggin anion. For compound 2 the capping VO group is disordered in six sites, while there are two types of sites for the capping VO group for compound 3. The IR spectra have been investigated.

A dinuclear manganese macrocyclic complex with functional pendant arms, [Mn 2 (II)HL 2 ](ClO 4 ), has been prepared by the cyclocondensation of sodium 2,6-diformyl-4-methylphenolate with N , N -bis(2-aminoethyl)- N -(2-hydroxybenzyl)amine and subsequent transmetallation of Mn(II)(ClO 4 ) 2 . In the molecular structure of the complex, each pendant arm is bound to an adjacent manganese atom and both arms lie on the same side of the resulting tetra-imine macrocycle. Each manganese(II) ion is in a distorted octahedral configuration. The variable-temperature magnetism and the cyclic voltammogram of the complex have also been investigated. In the catalytic study, this compound exhibits a high activity for catalyzing disproportionation of H 2 O 2 to O 2 .

The syntheses, characterization and luminescent properties of europium(III) and terbium(III) cryptates synthesized by [2+3] condensation of tris(2-aminoethyl)amine with 2,6-diformyl-4-R-phenol (R = Cl, F, tBu) in the presence of Eu3+ or Tb3+ have been reported. The crystal structure of the europium cryptate (R = Cl) shows that the coordination number of the EuIII ion is nine and that a guest water molecule is encapsulated in the cavity. The cryptates have a high stability which confers good fluorescence properties in solution.

A novel cyanide-bridged bimetallic assembly, [Cu(1,3-Pn)2]2[FeIII(CN)6]ClO4 · 2H2O (1,3-Pn = 1,3-diaminopropane), derived from [Fe(CN)6]3− building blocks and four-coordinated bisdiamine metal(II) ions [Cu(1,3-Pn)2]2+ is described and characterized by X-ray crystal analysis. The compound contains a two-dimensional network structure extended through FeIII—CN—Cu linkages. Mossbauer experimental results indicate that the iron is ferric (Fe3+) in the complex. Cryomagnetic measurements reveal an antiferromagnetic exchange interaction between the nearest paramagnetic metal ions in the compound. The exchange mechanism was also discussed.

Interesting complexes containing a mnt2− bridge, based on the reaction of [M(mnt)2]2− [M = Ni or Cu] with [Cu(LH)]+, have been prepared and characterized by e.s.m.s., i.r and u.v–vis. spectroscopic techniques and by electrochemistry. The complexes show weak antiferromagnetic interactions between magnetic centers. The X-ray analysis of the molecular structure of [Cu(LH)]2[Ni(mnt)2] has been completed. It structurally features the CN group of mnt2− which can act as a bridging ligand between two transition metals.

The syntheses and structures of [Ag(azpy)](NO3)⋅(H2O)⋅(CH3OH) (1), [Cu(azpy)2](ClO4) (2), [Cu(azpy)2(H2O)2](NO3)2⋅(H2O)2 (3) and [Cu(azpy)2(H2O)2](ClO4)2⋅(C2H5OH)2 (4), where azpy = trans-4,4′-azopyridine, are reported to test the dependence of network topology on counter anions and π−π interactions. Complex 1 contains pairs of linear chains of alternating AgI ions and azpy ligands, resembling a ladder structure in which the ligands form π−π interactions (with a distance of 3.53 A) and AgAg interactions (with a distance of 3.30 A). Complex 2 exists as a 3D adamantoid polymer in which each CuI center is coordinated to four azpy ligands in a tetrahedral geometry, the ligands are in turn coordinated to four other CuI centers. The cavities are filled with four other adamantoid units forming five interpenetrating networks. Complexes 3 and 4 are composed of two-dimensional sheets in which the CuII atom is coordinated in an octahedral geometry to two water molecules and four ligands. The ligands are in turn coordinated to four other CuII centers. While the sheets in complex 3 display inclined 2D interpenetration, the sheets in complex 4 are all parallel and isolated, with an intersheet separation of ca. 4.7 A.

The crystal structure of a 1D chain complex, [Cu(SCN)(deae)]n (1) (Hdeae N,N-diethylamino ethanol), with mixed bridges was determined. The structure is composed of a dimeric Cu(II) unit with two bridging m 3 -h 2 -aminoethanolato ligands, while the units are bridged by end-to-end thiocyanato groups to form a 1D chain. The variable temperature magnetic susceptibility of 1 and [Cu(SCN)(dmae)]n (2) (HdmaeN,N-dimethylamino ethanol) in the temperature 5‐300 K have been interpreted in terms of simple dimer model approximation (H 2JSA·SB). The magnetic behaviors show that the aminoethanolato bridges mediate a moderately strong antiferromagnetic exchange interaction with the fitting values g 1.96(3), J 175(3) cm 1 for 1 and g2.016(7), J 205.4(7) cm 1 for 2, respectively. © 2000 Elsevier Science Ltd. All rights reserved.

The new supramolecular phosphoric complex [H 2 (C 4 H 10 N 2 )] 2 (H 2 PO 4 ) 4 has been obtained by the hydrothermal reaction of piperazine hexahydrate (C 4 H 10 N 2 ·6H 2 O), Zn(OAc) 2 with H 3 PO 4 in the molar ratio of 1:1:2 at 180°C. The compound was characterized by the means of elemental analysis, FT-IR, TGA-DTA, and single crystal X-ray analysis. The structure was determined with data: triclinic, space group P -1(no. 2), a=7.020(9) A , b=7.694(2) A , c=12.076(2) A , α =84.41°, β =81.51°, γ =62.92(2)°, V=574.04(2) A 3 , and Z =1. Single crystal structure analysis gave R =0.0324, R w =0.0947 for 1441 observed reflections [ I (26( I )]. The structure is unique with three (HPO 4 ) 2− groups and three H 2 O molecules connecting each other alternatively into a ring by the interaction of hydrogen-bonds and (C 4 H 10 N 2 H 2 ) 2+ cations reside in the rings to form an infinite 3D network only by hydrogen-bonding interaction.

The template reaction of sodium 2,6-diformyl-4-methylphenolate (sdmp) and [ N , N -bis(2-aminoethyl)]aminoacetic acid (baaa) subsequently transmetalled with Mn(II)(ClO 4 ) 2 ·6H 2 O has resulted in the generation of a dinuclear mixed-valence Mn(II)Mn(III) complex of a tetraimine macrocyclic Schiff base with a single carboxylic arm, in which unusual group elimination of a baaa moiety happened at one side chain in the process of the cyclocondensation and transmetallation. The X-ray structure of the complex shows that the macrocyclic ligand is asymmetric, where the coordination polyhedron of one Mn atom, six-coordinate, is distortedly octahedral and that of the other Mn atom, seven-coordinate, is distortedly pentagonal-bipyramidal. The complex has been investigated on its variable temperature magnetic behavior together with ESR spectral and electrochemical properties.

The synthesis and crystal and molecular structure of [Gd(H3L)(NO3)(H2O)](ClO4)2 are reported. The complex crystallizes in the orthorhombic system, space group Pbca with lattice parameters a = 16.974(8), b = 20.010(4), c = 25.202(4) A, and Dcalc = 1.736 mg m−3, forZ = 8. The coordination number of gadolinium (III) is nine, and its coordination geometry is a distorted monocapped square antiprisms. In the complex, three benzene rings make dihedral angles of 91.7, 92.7, 66.3°, respectively. A water molecule acts as a guest molecule encapsulated in the cryptate.

The template reaction of sodium 2,6-diformyl-4-chlorophenolate and N,N-bis(2-aminoethyl)–hydroxyethylamine followed by in situ transmetallation of Mn(ClO4)2 results in a mononuclear manganese(III) complex of one 21-membered asymmetric 2:2 Schiff base macrocycle, in which a hydroxyethyl group of the amine has been eliminated and ring contraction at one chamber of the macrocycle has occurred to form an imidazolidine ring. An X-ray study indicates that the geometry about the manganese(III) ion is distorted octahedral. The electrochemical behavior of this complex in MeCN has been studied by cyclic voltammetry.

A new facile method of synthesis of calix[4]arene amide via the aminolysis of the calix[4]arene esters was reported. One ethyl ester of the compound (2) was aminolysized byn-butylamine. The crystal structure of compound (1)shows that one ethyl ester of compound (1) enters into thecavity of another compound (1) forming a long chainhost-guest supramolecule. From the 2D NMR data, the compound(1) does not assemble in THF or CHCl3 solution. The CH-π interaction and crystallization energy might be theimportant driving forces for forming the self-assembledcalix[4]arene.