A new type of supramolecular assembly consisting of crown ether complex cation and a polyoxometalate anion: Synthesis and crystal structure of [Na(C20H24O6)(CH3CN)2]2[Mo6O19] · 4CH3CN

A novel supramolecular assembly consisting of sodium-dibenzo-18-crown-6(DB18C6) complex cation [Na(C₂₀H₂₄O₆)(CH₃CN)₂]²⁺ and isopolyanion [Mo₆O₁₉]²⁻ has been demonstrated in the 3D structure of [Na(C₂₀H₂₄O₆)(CH₃CN)₂]₂[Mo₆O₁₉] · 4CH₃CN (1). Weak intermolecular forces (C–HO hydrogen bonds) between isopolyanion and crown ether play a significant role in the construction of supramolecular framework in the crystal structure of 1. Compound 1 has been characterized in the solid state by single crystal X-ray diffraction, IR, CHN analysis, and TGA.     

Self-assembled chloro-bridged metallo-prismatic cations of the general formula [M6(η-C5Me5)6(μ3-tpt)2(μ-Cl)6] (M = Rh, Ir; tpt = 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine)

Two cationic pentamethylcyclopentadienyl metal-based hexanuclear complexes with trigonal prismatic architecture have been synthesised through a two-step strategy. The dinuclear complexes [M(η⁵- C₅Me₅)(μ-Cl)Cl]₂ (M = rhodium and iridium) react with 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (tpt) in dichloromethane to give the trinuclear complexes [Rh₃(η⁵-C₅Me₅)₃(μ₃-tpt)Cl₆] (1) and [Ir₃(η⁵-C₅Me₅)₃(μ₃-tpt)Cl₆] (2), respectively. Addition of silver triflate to 1 and 2 in dichloromethane connects two identical triangular panels to form the hexanuclear metallo-prismatic cations [Rh₆(η⁵-C₅Me₅)₆(μ₃-tpt)₂(μ-Cl)₆]⁶⁺ (3) and [Ir₆(η⁵-C₅Me₅)₆(μ₃-tpt)₂(μ-Cl)₆]⁶⁺ (4), respectively. Cations 3 and 4 have been isolated as their triflate salts and characterised by ¹H NMR, IR and UV/visible spectroscopy.     

Synthesis, characterization and crystal structure of cis,mer-[ReH(CO)2{PPh(OMe)2}3]

The dicarbonylhydride complex cis,mer-[ReH(CO)₂{PPh(OMe)₂}₃] (1) was serendipitously obtained when, in an attempt to replace a CO ligand by the phosphonite ligand PPh(OMe)₂ in [ReH(CO)₃(L)] (L = PPh₂OCH₂CH₂OPPh₂), this complex was treated with PPh(OMe)₂ under UV irradiation. The complex 1 was characterized by IR, ¹H and ³¹P{¹H} NMR spectroscopy and by crystal structure determination. The spectroscopic features are consequent with the cis,mer configuration showed by the X-ray crystallographic analysis of the complex. The environment of the metal centre is a distorted octahedron.     

Synthesis, crystal structure and magnetic properties of a new three-dimensional porous framework: [Gd2(BDA)3(DMF)2(H2O)4] · 2DMF

The open framework compound of [Gd₂(BDA)₃(DMF)₂(H₂O)₄] · 2DMF (1), prepared by heating GdCl₃ with 2,2′-bipyridyl-4,4′-dicarboxylatic acid (BDA) in mixed solvent, is constructed from BDA linking up polymeric [GdO₅(DMF)(H₂O)₂]_n tethers. The 1D channels are filled with coordinated and uncoordinated DMF molecules hydrogen bonding to terminal aqua ligands. The study of the temperature dependent magnetic susceptibilities revealed that there are ferromagnetic interactions between intra-chain Gd^III atoms and weak antiferromagnetic interactions between inter-chain Gd^III atoms.     

The structural characterization and hydroformylation activity of the tri-rhodium complex [Rh3(μ2-dppm)2(μ2-CO)3(K-CO)3]BF4

Rh₂(cod)₂(μ₂-dppm)(μ₂-Cl)]BF₄ (1) rearranges under carbon monoxide to give [Rh₃(μ₂-dppm)₂(μ₂-CO)₃(K¹-CO)₃]BF₄ (2). Complex 2 has been structurally characterized by single crystal X-ray crystallography. The hydroformylation activities of 1 and 2 were compared for substrates styrene and 1-hexene and the activity of 2 found to be unexpectedly high.     

Synthesis, crystal structure and NMR of [Na(DB18C6)(CH3CN)]3[α-AsM12O40] (M = Mo/W)

Two super-molecular complexes [Na(DB18C6)(CH₃CN)]₃[α-AsM₁₂O₄₀] (M = Mo/W) were obtained by solvothermal reaction and characterized by IR,¹H ¹³C and gUMBC NMR, X-ray. The result reveals that the complex consists of a [α-AsM₁₂O₄₀]³⁻ (M = Mo/W) anion with α-Keggin structure, and three complex [Na (DB18C6)(CH₃CN)]⁺ cations in which every sodium ion is located in the cavity of dibenzo-18-crown-6 with 6 Na–O bonds and coordinated with one of the terminal O atom of [α-AsM₁₂O₄₀]³⁻ (M = Mo/W) and the N atom of CH₃CN from two sides of the distorted DB18C6 plane, respectively. The three terminal O atoms linked with sodium ion are from a single M₃O₁₃ (M = Mo/W) triplet of the α-Keggin metalatoarsenate anion, and M–O_b (M = Mo/W) bonds exhibit alternating single–double bond character.     

Synthesis, structural characterization and ethylene polymerization behavior of complex [Ph4P][CrCl3{HB(pz)3}] [HB(pz)3 = hydrotris(1-pyrazolyl)borate]

Reaction of CrCl₃(THF)₃ with K[HB(pz)₃] in THF leads to the formation of the complex K[CrCl₃{HB(pz)₃}] (1). The salt metathesis of complex 1 with [Ph₄P]Br in CH₂Cl₂ yields the complex [Ph₄P][CrCl₃{HB(pz)₃}](2). The structure of complex 2 · CHCl₃ has been determined by single crystal X-ray diffraction. In the anion the metal centre shows a distorted octahedral geometry with the hydrotris(1-pyrazolyl)borate bonded as N,N′,N″-donor tripod ligand and three chloride atoms completing the co-ordination sphere. Complex 2 in the presence of MAO leads to the formation of an active catalyst for the polymerization of ethylene.     

Synthesis and structure of [{As(NBu)3}2Li6] containing an [As(NBu)3] trianion

Attempts to prepare the [As(N^tBu)₃]³⁻ trianion by the reaction of As(NMe₂)₃ with [^tBuNHLi]_n (1:3 monomer equiv.) proved unsuccessful. However, if the reaction is carried out with an excess of ^tBuNH₂ (3 equiv.) the target complex [{As(N^tBu)₃}₂Li₆] (1) is obtained. This is the first example of a complex containing an [As(NR)₃]³⁻ trianion.     

Synthesis and characterisation of tetraosmium carbonyl clusters bearing an azo type ligand: crystal and molecular structures of [Os4(μ-H)4(CO)11(NC5H4N=NPh)] and [Os4(μ-H)4(CO)10(MeCN)(NC5H4N=NPh)]

Reaction of [Os₄(μ-H)₄(CO)₁₀(MeCN)₂] with one equivalent of 4-phenylazopyridine (4-PAP) in CH₂Cl₂ at ambient conditions afforded two new tetraosmium clusters [Os₄(μ-H)₄(CO)₁₁(NC₅H₄N=NPh)] (1) and [Os₄(μ-H)₄(CO)₁₀(MeCN)(NC₅H₄N=NPh)] (2) in moderate yields. Compound 1 exists as a pair of isomers in solution, which differ in the location of the bridging hydride ligands. The molecular structures of clusters 1 and 2 consist of a highly distorted tetrahedral metal skeleton, with the azo ligand terminally bonded to an osmium atom.     

Two novel isomeric complexes supported by vanadates {V4O12}: [{Cu(dpa)2}2V4O12] (dpa = 2,2′-dipyridylamine)

Two Cu(II) complexes supported by tetravanadates, [{Cu(dpa)₂}₂V₄O₁₂] (1 and 2), have been synthesized under hydrothermal reactions. Structural analysis indicates that complexes 1 and 2 are isomeric and consist of a cyclic [V₄O₁₂]^4- anion bridged to two [Cu(dpa)₂]²⁺ moieties. Close inspection of complexes 1 and 2 reveals that the [V₄O₁₂]^4- anions adopt chair-like and boat-like configurations respectively, and are coordinated to each Cu(II) ions through a single terminal oxygen atom of two cross vanadium sites. Moreover, Complexes 1 and 2 exhibit trans- and cis-configurations, respectively.     

Ferromagnetic mixed tribridged dinuclear copper(II) complex [Cu2(OAc)2(OH)(dpa)2]PF6 · H2O (dpa = 2,2′-dipyridylamine): 3D superstructure based on hydrogen bond and π…π interaction

A new dinuclear complex [Cu₂(OAc)₂(OH)(dpa)₂] PF₆ · H₂O (1) is prepared and structurally and magneto-structurally characterized. The monocationic core contains one acetate in familiar bidentate η¹:η¹:μ₂-bridge and another in the rare monoatomic bridge along with one hydroxo intermediary. 1 packs through N–H…O and O–H…O hydrogen bonds and π…π interaction resulting a 3D supramolecular continuum and displays high-energy intraligand ¹(π − π^*) fluorescence and intraligand ³(π − π^*) phosphorescence in glassy solution.     

Ten-vertex osmamonocarbaboranes via arachno and nido {CB9} monocarbaboranes. Polyhedral contraction promoted by [OsCl2(PPh3)3] in MeOH and the crystal and molecular structure of [1-H-1,1-(PPh3)2-2-Ph-3-(OMe)-isocloso-1,2-OsCB8H7]

Reactions of [OsCl₂(PPh₃)₃] 1 with the [NEt₄]⁺ salts of the [6-Ph-nido-6-CB₉H₁₁]⁻ anion 2 and the [arachno-6-CB₉H₁₄]⁻ anion 3 each proceed selectively in methanol solution with the elimination of one boron-containing fragment from the starting cluster polyhedron, yielding together a short series of three novel 10-vertex hydridoosmamonocarbaboranes of isocloso {OsCB₈} cluster geometry.     

Synthesis, structural characterization and third-order non-linear optical property of new three-dimensional metal-organic polymer [Fe2(μ10-btc)0.5(μ2-ox)0.5(μ2-O)1.5]n

One new metal-organic polymer formulated as [Fe₂(μ₁₀-btc)_0.5(μ₂-ox)_0.5(μ₂-O)_1.5]_n 1 (btc = 1,2,4,5-benzenetetracarboxylate, pyramellitate; ox = oxalate) has been synthesized by low-temperature solid-state reaction and characterized by single-crystal X-ray diffraction, elemental analyses, TGA, IR spectra and UV–visible spectra. Complex 1 presents the first 3D coordination network structure constructed by bridging btc, ox and O mixed ligands. In 1, carboxyl groups of btc are all deprotonated and they have a new type of μ₁₀-btc coordination mode. The third-order non-linear optical (NLO) properties of the title compound 1 were also investigated and they exhibit the reverse saturable absorption and self-defocusing performance with modulus of the hyperpolarizability (γ) 5.98 × 10⁻³⁰ esu for 1 in a 7.45 × 10⁻⁴ mol dm⁻³ DMF solution.     

Bis(4′-phenyl-2,2′:6′,2″-terpyridine)ruthenium(II): Holding the {Ru(tpy)2} embraces at bay

The solid state structure of [Ru(Phtpy)₂][PF₆]₂ · 4MeCN has been determined (Phtpy = 4′-phenyl-2,2′:6′,2″-terpyridine); [Ru(Phtpy)₂]²⁺ cations pack into sheets by virtue of {M(tpy)₂}₂ embraces, and the MeCN solvent molecules are involved in NH–C interactions which prevent the efficient packing of adjacent sheets. Comparisons with related structures lead to some generalizations about packing motifs in salts containing [M(Phtpy)₂]²⁺ or [M(pytpy)₂]²⁺ cations (pytpy = 4′-pyridyl-2,2′:6′,2″-terpyridine).     

Diaquabis(4,4-bipyridine)copper(II) di(o-sulfobenzimidate) dichloromethane solvate, a two-dimensional Cu4(4,4-C5H4NC5H4N)4 rhombic grid clathrating guest dichloromethane

In the crystal structure of bis(4,4^′-bipyridine)diaquacopper(II) di(o-sulfobenzimidate) dichloromethane solvate, the host polycationic [Cu(4,4^′-C₅H₄NC₅H₄N)₂(H₂O)₂]_∞ rhombic grids stack over each other 8.16 Å apart along the c-axis of the orthorhombic Pbcn unit cell. The Cu₄(4,4^′-bpy)₄ rhombus clathrating a disordered dichloromethane molecule has a copper atom at the corner and the spacer heterocycle with pyridyl rings twisted by 21.8(2)°, as its side. The anions occupy the space between the layers; the grids interact with each other indirectly through water–anion hydrogen bonds [OO=2.766(4); ]. The structure sets a remarkable example of potentials born by the polyfunctional o-sulfobenzimidate moiety for construction of unusual architectures.     

Kinetics of Polyurethane Formation in Polymerization Reactions Using the Organometallic Diol (η5-C5H4CH2CH2OH)2Mo2(CO)6

Summary The kinetics of the dibutyltin diacetate (DBTA) – catalyzed polymerization reactions of (η⁵-C₅H₄CH₂CH₂OH)₂Mo₂(CO)₆ with Hypol 2000 (an isocyanate-terminated polyether prepolymer) and with 1,4-butanediol were studied, as were the kinetics of a copolymerization involving (η⁵-C₅H₄CH₂CH₂OH)₂Mo₂(CO)₆ and PEG-1000 (a poly(ethylene glycol)) with Hypol 2000. The purpose was to determine if (η⁵-C₅H₄CH₂CH₂OH)₂Mo₂(CO)₆ appreciably affected the overall rate of the polymerization reaction and if it changed the mechanism of the reaction. The kinetics were analyzed with a fitting program, which allowed extraction of the rate constants for the individual elementary steps in the mechanism. The results showed that (η⁵-C₅H₄CH₂CH₂OH)₂Mo₂(CO)₆ does not significantly alter the timescale of the reaction and that the same reaction mechanism is likely used as with the 1,4-butanediol and PEG-1000. There are some differences in the rate constants of the elementary steps, but these differences can be attributed to the increased steric crowding caused by the bulkier (η⁵-C₅H₄CH₂CH₂OH)₂Mo₂(CO)₆ diol. The effect of the (η⁵-C₅H₄CH₂CH₂OH)₂Mo₂(CO)₆ on the polymers’ physical properties was also investigated. As is the case with other segmented polyurethanes, the hydrogen bonding index (HBI) and the relative amount of soft segments of the (η⁵-C₅H₄CH₂CH₂OH)₂Mo₂(CO)₆-containing polyurethane correlate in a general way with the physical properties of the polymer.     

Ferromagnetic coupling in a novel dicyanamide-bridged dinuclear gadolinium(III) complex [Gd2(dca)4(OH)2 (NITpPy)4] (NITpPy = 4-pyridyl-nitronyl nitroxide radical)

The novel six-coordinated gadolinium(III) complex of formula [Gd₂(dca)₄(OH)₂(NITpPy)₄] (1) (dca = dicyanamide, NITpPy = 4-pyridyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-oxy-3-oxide) has been prepared and characterized by X-ray crystallography. Compound 1 is a dimer structure made up of double μ_1,5-dca-bridged gadolinium(III) ions and one terminal dca ligand; variable-temperature magnetic susceptibility measurements reveal the occurrence of a significant ferromagnetic interaction directly spin polarization through the NITpPy–Gd(III)–NITpPy pathway with J = 11.56 cm⁻¹.     

A novel disubstituted Lindqvist-type polyoxomolybdate [Te2Mo4O19] supporting two organic vanadyl moieties: Synthesis, characterization, and crystal structure of {[V(2,2-bipy)2]2(4,4-bipy)[Te2Mo4O19]}

The first example of disubstituted Lindqvist-type polyoxomolybdate {[V(2,2-bipy)₂]₂(4,4-bipy)[Te₂Mo₄O₁₉]} has been synthesized hydrothermally and characterized by elemental analyses, XPS, IR, TG-DTA and X-ray single crystal diffraction. The structural analysis shows that the neutral molecular unit [V(2,2-bipy)₂]₂[Te₂Mo₄O₁₉] consists of a novel Lindqvist-type polyanion [Te₂Mo₄O₁₉]⁶⁻ supporting two vanadyl moieties [V(2,2-bipy)₂]³⁺, and such neutral molecules are joined together by π − π stacking interactions between the pyridine groups to form a two-dimensional grid-like network with non-coordinating “guest” 4,4-bipys encapsulated.     

An intertwined double chain constructed by [SiMo12O40] clusters and unusual [Cu2(DF)2H2O] dimers

A new compound, {[Cu₂(DF)₂H₂O]₂SiMo₁₂O₄₀} (1) (DF = 4,5-diazafluoren-9-one), has been hydrothermally synthesized and characterized by routine methods and single crystal X-ray diffraction. In 1, all the DF only adopt the unusual bidentate coordination mode for the first time coordinating to Cu atoms to form copper-dimers which link [SiMo₁₂O₄₀]⁴⁻ clusters obtaining an intertwined double chain. Furthermore, the luminescent and electrochemical properties of the title compound have been studied.     

Synthesis of a fluorescent gold(I) complex with a thiosemicarbazone, [Au2(3-NO2-Hbtsc)4]Cl2 · 2CH3CN

Direct reaction of gold(I) chloride with 3-nitrobenzaldehyde thiosemicarbazone (3-NO₂-Hbtsc) in the presence of triphenylphosphine in acetonitrile has yielded ionic complex, [Au₂(3-NO₂-Hbtsc)₄]Cl₂ · 2CH₃CN (1). It exhibited an intense fluorescence band (λ_em) at 383 nm (λ_ex = 300 nm), and two bands of medium intensity at 413 and 436 nm (λ_ex = 350 nm). Complex 1 represents first example of ionic gold(I) complex with a thiosemicarbazone.