Synthesis and Crystal Structure of a Dicyanamide-bridged One-dimensional Gadolinium(III) Complex [Gd(dca)_3(phen)_2(H_2O)]_n

1 INTRODUCTION Dicyanamide is a versatile bridging ligand linking two or more metal ions with three nitrogen donor atoms[1～4]. The varieties of its coordination modes provide multifarious chances for designing new com- plexes with novel structures as well as interesting properties. Firstly, the complexes formulated as [M- (dca)2]n (M = Mn, Fe, Co, Ni, Cu, Cr)[5～9] mostly with 2D and 3D networks have been synthesized, and they usually exhibit high ordering temperatures. Afterwards, t…     

Synthesis and Crystal Structure of a New Complex [CuL(Phen)]·NO3

A new mononuclear copper(Ⅱ) complex [CuL(Phen)]·NO3 (L = 2-{2-[(3,5-dibro- mosalicylidene)amino]ethyl}-1H-1,3-benzimidazole, Phen = 1,10-phenanthroline) has been synthe-sized and its crystal structure was determined by X-ray diffraction method. It crystallizes in mono- clinic, space group C2/c with a = 24.966(7), b = 15.673(4), c = 16.600(5) (A), β = 123.981(4)o, C28H20Br2CuN6O4, Mr = 727.86, V = 5386(2) (A)3, Z = 8, Dc = 1.795 g/cm3, μ(MoKα = 3.826 mm-1, F(000) = 2888, the final R = 0.0508 and wR = 0.1024 for 5440 independent reflections with Rint = 0.1134. The title compound is composed of [CuL(Phen)]+ cation and NO3- anion. The coordination geometry around copper atom is a highly distorted trigonal bipyramid consisting of one benzi-midazole nitrogen atom, one phenolato oxygen atom and one phenanthroline nitrogen atom on the equatorial plane together with one imine nitrogen atom and one phenanthroline nitrogen atom occupying the axial positions. The hydrogen bonding and π-π stacking interactions link the copper complex molecules into a 3-D supramolecular structure.     

Cyanido-bridged one-dimensional systems assembled from [ReIVCl4(CN)2]2? and [MII(cyclam)]2+ (M = Ni, Cu) precursors

Three new cyanido-bridged heterometallic Re^IVNi^II and Re^IVCu^II one-dimensional systems were synthesized and extensively characterized both structurally and magnetically. Single-crystal X-ray diffraction analysis revealed that these compounds display a common topology, with chains composed of alternating [Re^IVCl₄(CN)₂]^2? and [M^II(cyclam)]²⁺ (M = Ni in 1, Cu in 2) or [Cu^II(N,N??-dimethylcyclam)]²⁺ (in 3) building units. Two different chain orientations with a tilt angle of ca. 51° to 55° are present in the crystal packing of these compounds. The magnetic susceptibility measurements suggest the presence of intrachain ferromagnetic interactions between the S = 3/2 Re^IV centers and the 3d metal ions: S = 1 Ni^II or S = 1/2 Cu^II. At low temperature, a three-dimensional ordered magnetic phase induced by interchain antiferromagnetic interactions (antiferromagnetic for 1 and 2; canted antiferromagnetic for 3) is detected for the three compounds.     

Crystal and Molecular Structure of Copper(Ⅰ) Complex [Cu(PPh3)2(NO3)]

Mononuclear copper( Ⅰ ) complex [Cu(PPh3)2(NO3)] has been synthesized by ligand reduction of cupric nitrate with PPh3 in methanol and characterized by elemental analyses, molecular weight determination, IR spectra and X-ray single crystal analysis; its molar conductivity has also been measured. The crystal is monoclinic, space group C2/c, a=24.52(5), b=9. 187(2), c=15. 489(3) A; β=116.69 (3)°, V=3118.7(11) A3, Z=4, F(000)=1520, Dc=1.584 g/cm3, R=0.0276,Rw= 0. 0321. The results show that PPh3 coordinates as a monodentate ligand to the Cu( Ⅰ ) atoms, and (NO3) behaves as a bidentate ligand in the prepared complex.     

Syntheses,crystal structures and magnetic properties of two honeycomb-layered bimetallic assemblies,K2[NiII(cyclam)]3[FeII(CN)6]2 · 12H2O and [NiII(cyclam)]3[FeIII(CN)6]2 · 16H2O

Two bimetallic assemblies, K₂[Ni^II(cyclam)]₃[Fe^II(CN)₆]₂ · 12H₂O (1) and [Ni^II(cyclam)]₃[Fe^III(CN)₆]₂ · 16H₂O (2) (cyclam = 1,4,8,11-tetraazacyclotetradecane), were obtained by reaction of K₄[Fe(CN)₆] and [Ni(cyclam)](ClO₄)₂ in aqueous media at different temperatures. Their crystals were structurally determined and magnetic properties were studied. Both of the compounds have honeycomb-layered structures, which are formed by Fe₆Ni₆ units linked through the cyanide bridges. Structure (1) consists of polyanions containing Ni^II–NC–Fe^II linkages and K⁺ cations, while structure (2) is a two-dimensional neutral layer containing Ni^II–NC–Fe^III linkages. The magnetic properties of (1) and (2) have been investigated in the 5–300 K range. Compound (1) exhibits a weak antiferromagnetic interaction with Weiss constant = –0.35 K; compound (2) shows ferromagnetic intralayer and antiferromagnetic interlayer interactions.     

Synthesis and Structure of the Copper(Ⅰ) Complex [Cu(PPh3)2(BH4)]

Mononuclear copper( Ⅰ ) complex [Cu(PPh3)2(BH4)] has been synthesized by ligand replacement reaction in methanol and characterized by elemental analyses, molecular weight determination, IR spectra and X-ray single crystal analysis,its conductivity has also been measured. The crystal is monoclinic, space group C2/c, a =24.776(4), b=9.173(7), c=15.564(2)A; β=116.10(1)°, V=3176.73 A3, Z =4, F(000)=1256, μ(MoKα)=8.11 cm-1, Dc=1. 26 g/cm3, M=602.79, R=0. 039, Rw= 0. 050. The results show that PPh3 coordinates as monodentate ligand to the Cu ( Ⅰ ) atoms, and BH4 behaves as a bidentate ligand in the prepared complex.The central copper atom belongs to tetrahedron coordination geometry.     

A Highly Asymmetric Gold(III) η3-Allyl Complex

A highly asymmetric Au^III η³-allyl complex has been generated by treating Au(η¹-allyl)Br(tpy) (tpy=2-(p-tolyl)pyridine) with AgNTf₂. The resulting η³-allyl complex has been characterized by NMR spectroscopy and X-ray crystallography. DFT calculations and variable temperature ¹H NMR suggest that the allyl ligand is highly fluxional.     

Aliphatic Hydroxylation by a Bis(µ-oxo)dicopper(III) Complex

By using molecular oxygen bis(μ-oxo)dicopper(III) complexes can be produced from Cu(I) complexes with ligand L(X) (L(X)=p-substituted N-ethyl-N-[2-(2-pyridyl)ethyl]-2-phenylethylamine; X=OMe, Me, H, Cl, NO(2)) in which the benzylic position of the ligand is activated and hydroxylated by the Cu(2)O(2) core (see reaction scheme). Detailed characterization of this new C-H bond activation reaction by the bis(μ-oxo)dicopper(III) core reveals important information on the fundamental chemistry underlying copper monooxygenase reactivity.     

Synthesis and Crystal Structure of an Organic-inorganic Complex [Hg(DMSO)_2(H_2O)]_2 [GeW_(12)O_(40)]·DMSO·H_2O

Hybrid organic-inorganic compounds have attracted increasing interest in recent years due to the possibility of combination of different characteristics of the compounds to get unusual structures, properties, or applications1. Polyoxometalates (POMs) whic…     

阳离子胶束对[Gr(III)-(Gly-Gly)]2+与茚三酮反应动力学的影响

The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of chromium dipeptide complex ([Cr(III)-Gly-Gly]2+) with ninhydrin under varying conditions has been investigated. The rates of the reaction were determined in both water and surfactant micelles in the absence and presence of various organic and inorganic salts at 70 ℃ and pH 5.0. The reaction followed first-and fractional-order kinetics with respect to [Cr(III)-Gly-Gly2+] and [ninhydrin]. Increase in the total concentration of CTAB from0 to 40×10-3mol·dm-3 resulted in an increase in the pseudo-first-order rate constant (kψ) by a factor of ca 3. Quantitative kinetic analysis of kψ-[CTAB] data was performed on the basis of the pseudo-phase model of the micelles. As added salts induce structural changes in micellar systems that may modify the substrate-surfactant interactions, the effect of some inorganic (NaBr, NaCl, Na2SO4) and organic (NaBenz, NaSal, NaTos) salts on the rate was also explored. It was found that the tightly bound counterions (derived fromorganic salts) were the most effective.     

Implications for Mercury Toxicity from the Structure of An Oxacalix[3]arene-HgCl 2 Complex?

t -Butyloxacalix[3]arene tris (diethylacetamide), known to mimic the cellular sodium ion selectivity filter, has been shown to bind HgCl 2 . The dimeric complex crystallises in the triclinic space group P 1 with a =17.3019(6) Å, b =18.7821(4) Å, c =19.9025(5) Å, ! =67.3010(10), # =77.664(2); % =77.238(2) and D c =1.370 g cm m 3 for Z =4. Refinement based on 37,818 observed reflections gave a final R value of 0.0483. Implications for routes of mercury uptake are discussed.     

Synthesis and Crystal Structure of a Complex Bimetallic Salt [Ni(trans_[14]diene)] [Ni (mnt)_2]

1INTRoDUCTIONMacrocycliccoordinationcomPOundshavebeenwidelyinvestigatedinthepastdecadesbecauseoftheirrelationshiptocomplexesofbiologicalsignificancesuchasthePorphyrinsandcorrins(lJ.Structuresofmanymacrocycliccompoundshavebeenre-ported,especiallythecompoundscontainingN4macrocyclicligands"'.However,toourknowledge,onlyafewcrystalstructuresofcomplexbimetallicsaltscontainingmacrocyclicligandshavebeendeterminedbyX-raydiffractionmethod.Inthispa-per,werePortthesynthesisandstructureofthetit1ecom…     

Two yttrium(III) coordination compounds containing a3-ptz or atza [a3-ptz = 5-[N-acetato(3-pyridyl)]tetrazole; atza = 5-aminotetrazole-1-acetato]

Two yttrium(III) coordination compounds, [Y(a3-ptz)₂(H₂O)₅]Cl?·?4H₂O (1) and [Y(atza)₂(H₂O)₂(CH₃OH)]Cl (2) [a3-ptz?=?5-[N-acetato(3-pyridyl)]tetrazole; atza?=?5-aminotetrazole-1-acetato], have been synthesized. Single-crystal X-ray diffraction analysis reveals that 1 has a distorted monocapped square-antiprism coordination geometry around Y^III. Complex 2 is a distorted pentagonal bipyramid with coordination from four atza ligands, two waters, and one methanol; the coordination of atza in 2 leads to its 1-D polymeric chain structure. 1 and 2 are self-assembled to form 3-D supramolecular structures through hydrogen bonds. The luminescence properties of 1 and Ka3-ptz were investigated at room temperature in the solid state.     

Crystal and molecular structure of cyano(ethylenediamine) [Ethylenediamine-N,N′-Diacetato(1-)]Cobalt(III) Trichloromercurate(II) [Co(HEdda)En(CN)]HgCl3

An X-ray diffraction analysis of [Co(HEdda)En(CN)]HgCl₃ crystals (a = 6.664(4), b = 16.613(13), c = 16.684(7) å, space group P2₁2₁2₁, Z = 4) showed that the crystals contain distorted tetrahedra HgCl₄ linked by one of their vertices into infinite chains [HgCl₃] _n ^n- . In isolated complex cations, three donor atoms of the HO₂CCH₂NHCH₂CH₂NHCH₂CO ₂ ^- (HEdda) ion occupy a face of the coordination octahedron around the cobalt atom; the opposite face is occupied by the cyanide ion and the nitrogen atoms of the ethylenediamine (En) molecule; the latter are in trans positions relative to the terminal donor atoms of the HEdda ligand.     

Synthesis of Mn3O4 Nanorods by Solid-State Thermal Decomposition of Manganese(III) Schiff Base Complex [Mn(Brsal-mepn)(μ1,3-N3)]n

Hausmannite Mn₃O₄ nanorods were successfully prepared via solid-state thermal decomposition route with manganese(III) Schiff base complex [Mn(Brsal-mepn)(μ_1,3-N₃)]_n as manganese source in air at 400 °C for 4 h. Powder X-ray diffraction, Fourier transform infrared spectrometry and scanning electron microscopy were used to characterize Mn₃O₄ nanoparticles. These results confirm that the resulting manganese oxide was pure single-phase Mn₃O₄ nanoparticles. Using the present method, Mn₃O₄ nanorods can be product without expensive organic solvent and complicated equipment.     

Is There an Entrance Complex for the F+NH3 Reaction?

Challenges associated with the theoretical and experimental kinetics of the F+NH₃→HF+NH₂ reaction suggest the need for a more‐precise potential surface. We have investigated the reactants and the products of the reaction, as well as the transition state and two complexes, with rather rigorous ab initio methods. The F????NH₃ complex existing in the entrance valley is predicted to lie 13.7 kcal mol^?1 below the reactants. A small classical barrier of 2.0 kcal mol^?1 separates this entrance well from products HF+NH₂. These results explain the observation by Persky of unprecedented inverse temperature dependence for the F+NH₃ rate constants. The strong hydrogen‐bonded complex FH????NH₂ exists in the exit valley, and with a binding energy of 9.9 kcal mol^?1 relative to separated products. The vibrational frequencies of all stationary points are predicted with the CCSD(T)/aug‐cc‐pVQZ method.     

Synthesis and Photoluminescence of a New Red PhosphorescentIridium(III) Quinoxaline Complex

Much attention has been paid to the phosphorescent materials in recent years for their potential application as highly efficient electroluminescent (EL) emitters in organic light emitting diodes (OLEDs) 1-2. Heavy metal complexes, particularly those containing Pt and Ir, where strong spin orbit coupling leads to singlet-triplet state mixing, can result in high efficiency electrophosphorescence in OLED 3-5. Among the many kinds of metal complexes, iridium complexes are the most effective …