Synthesis and characterization of mono- and binuclear copper(II) complexes with 2,2′:6′,2″-terpyridine (terpy) and carboxylates: X-ray crystal structure of [Cu(terpy)(OOCH)(OH2)](ClO4) complex

Perchlorate and hexafluorophosphate salts of monomeric [Cu(terpy)(OOCH)(OH₂)]⁺ and dimeric [Cu(terpy)(OOCR)]₂²⁺ cations (terpy = 2,2′:6′,2″-terpyridine, R = CH₃ or C₂H₅) have been synthesized and characterized by IR, electronic and ESR spectra, and analytical data. Spectroscopic results indicate a five-coordinate, close-to-square pyramidal geometry around the copper(II) ion. The half-field absorption in the ΔM_s = 2 region of powdered X-band ESR spectra has been observed for the dimeric species. The crystal structure of [Cu(terpy)(OOCH)(OH₂)](ClO₄) has been determined by X-ray diffraction methods. The compound crystallizes in the space group P2₁/c with unit-cell dimensions: a = 7.341(3), b = 13.919(2), c = 18.081(3) Å, β = 101.68(3)°, V = 1809(1) ų, Z = 4. The structure was refined to R = 0.044, R_w = 0.051.     

New iron(II) spin crossover coordination polymers [Fe(μ-atrz)3]X2·2H2O (X = ClO4¯, BF4¯) and [Fe(μ-atrz)(μ-pyz)(NCS)2]·4H2O with an interesting solvent effect

A potential bridging triazole-based ligand, atrz (trans-4,4'-azo-1,2,4-triazole), is chosen to serve as building sticks and incorporated with a spin crossover metal center to form a metal organic framework. Coordination polymers of iron(II) with the formula [Fe(μ-atrz)(3)]X(2)·2H(2)O (where X = ClO(4)(-) (1·2H(2)O) and BF(4)(-) (2·2H(2)O)) in a 3D framework and [Fe(μ-atrz)(μ-pyz)(NCS)(2)]·4H(2)O (3·4H(2)O) in a 2D layer structure were synthesized and structurally characterized. The magnetic measurements of 1·2H(2)O and 2·2H(2)O reveal spin transitions near room temperature; that of 3 exhibits an abrupt spin transition at ~200 K with a wide thermal hysteresis, and the spin transition behavior of these polymers are apparently correlated with the water content of the sample. Crystal structures have been determined both at high spin and at low spin states for 1·2H(2)O, 2·2H(2)O, and 3·4H(2)O. Each iron(II) center in 1·2H(2)O and 2·2H(2)O is octahedrally coordinated with six μ-atrz ligands, which in turn links the other Fe center forming a strong three-dimensional (3D) network; counteranion and water molecules are located in the voids of the lattice. The FeN(6) octahedron of 3·4H(2)O is formed with two atrz, two pyrazine (pyz) ligands, and two NCS(-) ligands, where the ligands atrz and pyz are bridged between iron centers forming a 2D layer polymer. A zigzag chain of water molecules is found between the layers, and there is a distinct correlation between the thermal hysteresis with the amount of water molecules the exist in the crystal.     

Ethylenediamine-N,N"-Diacetate Ion (Edda2–) as a Tridentate Ligand: Synthesis and Structure of the [Co(Edda)(Dien)]ClO4 · H2O and [Co(Edda)(En)(CN)] · 2H2O Complexes

The cobalt(III) complexes with tridentate ethylenediamine-N,N"-diacetate ions (Edda^2–) and additional ligands, namely, diethylenetriamine (Dien) or ethylenediamine (En) and cyanide ions, were synthesized. As follows from X-ray diffraction analysis of [Co(Edda)(Dien)]ClO₄· H₂O (monoclinic crystals with a = 9.243 (2) Å, b = 14.167 (4) Å, c = 13.046 (3) Å, = 91.19 (2)°, Z = 4, space group P2₁/c), the secondary N atom of the Dien ligand occupies the trans-position relative to the N atom of the Edda^2– ligand, which contains a free acetate group. Two fac-isomers of [Co(Edda)(En)(CN)] with the CN^– ion in the cis- and trans-positions relative to the oxygen atom of the carboxyl group were isolated, and the structure of the trans-(O,CN)-[Co(Edda)(En)(CN)]· 2H₂O was determined: monoclinic crystals with a = 9.136 (3) Å, b = 15.484 (3) Å, c = 10.564 (3) Å, = 110.67 (5)°, Z = 4, space group P2₁/c.     

Crystal structures of complexes of 3,5,6-tris(2-pyridyl)-1,2,4-triazine: [Pb(TPT)(NO3)2] n and [Pb(TPT)2(ClO4)(H2O)] · ClO4 · H2O

Two new Pb(II) complexes, [Pb(TPT)(NO₃)₂] _n (1) and [Pb(TPT)₂(ClO₄)(H₂O)] · ClO₄ · H₂O (2) (TPT is the abbreviation of 3,5,6-tris(2-pyridyl)-1,2,4-triazine), have been synthesized and characterized by single-crystal X-ray diffraction. Lead(II) in the compounds of 1 and 2 is nine coordinate (rare mode), PbN₃O₆ and PbN₆O₃, respectively. Both have hemidirected coordination geometries. The supramolecular features in these complexes are guided/controlled by hydrogen bonding and weak directional intermolecular C–H ··· O and π ··· π interactions. The thermal stabilities of 1 and 2 were investigated by thermogravimetric measurements.     

Uncommon Behavior of Copper(I) Tetrafluoroborate and Perchlorate in [Cu(DAF)(H2O)]BF4and [Cu(DAF)(ClO4)] π-Complexes (DAF—Diallyl Formamide)

Crystals of [Cu(DAF)(H₂O)]BF₄(I) and [Cu(DAF)(ClO₄)] (II) (DAF is diallyl formamide) were synthesized by an alternate-current electrochemical method, and their structures were determined (MoK radiation, 1247 and 859 independent reflections with I 2(I), R= 0.043 and 0.032 for Iand II, respectively). The complexes crystallize in space group P2₁/n, Z= 4. For I, a= 10.782(3) Å, b= 12.096(5) Å, c= 9.185(3) Å, = 103.62(3)°, and V= 1164.2(7) ų; for II, a= 10.064(3) Å, b= 10.753(6) Å, c= 10.002(3) Å, = 87.52(4)°, and V= 1081.4(8) ų. The copper atom in structures Iand IIcoordinates both C=C bonds in one DAF molecule and oxygen atom of the amide group of another DAF molecule, as well as an oxygen atom of H₂O (in I) or ClO₄(in II) in the axial position. The uncommon behavior of the anions in structures Iand IIis explained by their different values of Pierson hardness.     

A novel oxo-bridged Mn4 mixed salt, {[(n-Bu4N)(ClO4)]2[Mn4O6(Tacn)4](ClO4)4} · 2H2O and its analogue Mn4 cluster [Mn4O6(Tacn)4](ClO4)4 · 2H2O (Tacn = 1,4,7-triazacyclononane)

A novel Mn₄ mixed salt, {[(n-Bu4N)(ClO₄)₂]₂[Mn₄O₆(Tacn)₄](ClO₄)} · 2H₂O (I) and its analogue [Mn₄O₆(Tacn)₄](ClO₄)₄ · 2H₂O (II) (Tacn = 1,4,7-triazacyclononane), have been constructed and structurally characterized by X-ray crystallography. The [Mn₄O₆]⁴⁺ core of these two complexes presents an adamantine-like skeleton. Each Mn atom of both complexes is coordinated by three nitrogen atoms of Tacn and connects other Mn atoms through a single-oxo bridge in an octahedral environment. Two complexes crystallize in monoclinic crystal system, space group C2/c with a = 24.296(11) Å, b = 10.986(5) Å, c = 32.746(15) Å, β = 101.975(6)°, Z = 8 for I and space group P2₁/n with a = 21.141(10), b = 11.306(5), c = 21.576(10) Å, β = 111.155(5)°, Z = 4 for II.     

Synthesis,characterization and 1H NMR studies of [Co(en)2(malH)2]ClO4·H2O

The trans-[Co(en)₂(malH)₂]ClO₄·H₂O complex was prepared by the reaction of sodium hydrogen malonate with [Co(en)₂(H₂O₂](ClO₄)₃ in the presence of a large concentration of perchlorate ion. It showed a three-band visible spectrum (γγ_max 357, 448 and 542.6 nm), diagnostic of a trans-MA₄B₂ system and gave characteristic IR bands as expected for a trans-bisethylenediamine cobalt(III) complex. The ¹H NMR spectrum in DMSO-d₆ revealed a broad band at 5.8 ppm assignable to the amino hydrogen and a single band at 2.68 for the ethylene group of the chelate ring. The

group of the hydrogen malonate ion appeared as a sharp singlet at 2.95 ppm and integration showed the presence of two bimalonate groups. The reactive methylene protons were found to be exchangeable. Ion association by counter ions of the complex ion in DMSO-d₆ showed no preference among amino protons. This is as expected for trans complexes with D_2h-symmetry.     

Syntheses and crystal structures of two Cd(II) coordination polymers: one-dimensional chain [Cd(C4H6N2)2(C4H2O4)(H2O)2] n and two-dimensional sheet [Cd(C4H6N2)(H2O)(C4H4O4)] n · n H2O

Two new Cd(II) coordination polymers, [Cd(C₄H₆N₂)₂(C₄H₂O₄)(H₂O)₂] _n (1) (where C₄H₆N₂?=?2-methylimidazole, C₄H₂O₄?=?fumarate), and [Cd(C₄H₆N₂)(H₂O)(C₄H₄O₄)] _n ?·?nH₂O (2), (where C₄H₄O₄?=?succinates), have been prepared and structurally characterized by single crystal X-ray diffraction. Complex 1 crystallizes in the triclinic space group P 1 in a one-dimensional chain structure, in which carboxy is monodentate; a three-dimensional supermolecular network structure was formed through hydrogen bonding. In complex 2, the coordination geometry of the Cd atoms is a pentagonal bipyramid, and a two-dimensional sheet is formed though carboxyl group bridging. In 1 and 2, IR spectra indicate the presence of bridging carboxyl groups, confirmed by structure analyses.     

Crystal Structure of Calcium [Aqua(Nitrilotriacetatocobaltate(II)] Tetrahydrate,Ca[Co(Nta)(H2O)]2· 4H2O

Crystals of Ca[Co^II(Nta)]₂· 6H₂O (I), where Nta^3–is a nitrilotriacetate ion, were synthesized and studied using X-ray diffraction analysis. They were found to be monoclinic: a= 6.991(1), b= 10.031(1), c= 16.238(3) Å, = 98.50(1)°, V= 1126.2(3) ų, space group P2₁/n, Z= 2, R ₁= 0.0241, wR ₂= 0.0636, GOOF = 1.050 (for 3132 reflections with I> 2(I)). Structure Iis composed of {[Co(Nta)(H₂O)]^–}₁anion chains united by Ca²⁺cations into a three-dimensional framework. The coordination polyhedra of Co and Ca atoms are distorted octahedra. The Co(II) atom environment includes atoms N(1), O(1), O(3), and O(5) of one Nta^3–ligand, a carbonyl O(2)" atom of the neighboring anion fragment, and an O(w1) atom of the water molecule. The shortest bond is formed by the Co atom with the bridging O(2)" atom in trans-position relative to atom N(1). The Co–O(2)" distance (2.029 Å) is noticeably shorter than the other bond lengths, Co–O(Nta) (2.069–2.103 Å), Co–O(w1), and Co–N(1) (2.155 and 2.177 Å, respectively). Cations Ca²⁺are located in the inversion centers and involve in their coordination atoms O(4), O(6), O(w2), and the oxygen atoms symmetrically bond to them and arranged at 2.271(1), 2.420(1), and 2.351(2) Å, respectively. The structural formula of the title compound is {Ca(H₂O)₂[Co(Nta)(H₂O)]₂}₃· 2H₂O.     

Synthesis and Crystal Structure of a Novel Co(II)-Nitronyl Complex [Co(IM2-Py)(PCA)(N_3)_2]

1 INTRODUCTION The design and synthesis of molecule-based mag-netic materials is one of the major subjects of mate-rials science. Nitronyl nitroxides acting as useful pa-ramagnetic building blocks have been extensively usedto assemble molecular magnetic materials in the pastfew years[1～5]. However, their weakly basic charac-ter strongly limits their coordination ability. Mean-while, the azide anion is a versatile ligand which canlink the transition metal atoms with different coor-dinatio…     

Identification of the cobalt(II) chloride ‘mixed’ solvate Co4Cl8(H2O)4(MeCN)6: the ionic structure trans-[Co(H2O)2(MeCN)4] trans-[Co(H2O)2(MeCN)2(CoCl4)2]

The structure of the title compound features mononuclear octahedral Co^II cations, trans-[Co(H₂O)₂(MeCN)₄]²⁺, and trinuclear anions, trans-[Co(H₂O)₂(MeCN)₂(CoCl₄)₂]^2–; the latter centrosymmetric units contain a central octahedral Co(H₂O)₂(MeCN)₂ moiety with two tetrahedral [CoCl₄]^2– ligands. These two large ions are held in a network of intra- and inter-molecular hydrogen bonding.     

THE PHENOMENON OF KRYPTORACEMIC CRYSTALLIZATION. PART 1. COUNTERION CONTROL OF CRYSTALLIZATION PATHWAY SELECTION. PART 4. THE CRYSTALLIZATION BEHAVIOR OF (+/−)-[Co(tren)(NO2)2]Br(I), (+/−)-[Co(tren)(NO2)2]2Br(ClO4) · H2O(II), (+/(−)-[Co(tren)(NO2)2]ClO4(III) AND ATTEMPTS TO SOLVE THE STRUCTURE OF (+/−)-[Co(tren)(NO2)2]NO3(IV)

Abstract

Racemic aqueous solutions of (+/?)-[Co(tren)(NO₂)₂]Br (I), (+/?)-[Co(tren)(NO₂)₂]ClO₄ (III) and [Co(tren)(NO₂)₂]NO₃(IV) crystallize as racemates. By contrast, the double salt, (+/?)-[Co(tren)(NO₂)₂]₂Br(ClO₄) · H₂O(II), produces kryptoracemic crystals belonging to the enantiomorphic space group P2₁2₁2₁ (No. 19). The former three species crystallize with one molecule in the asymmetric unit; in the latter, a racemic pair is the asymmetric unit, a fact which is hidden by the enantiomorphic nature of its space group – thus the name of the crystallization phenomenon reported. In (II) pairs of cations are related by an approximate, non-crystallographic, inversion center. The crystal structure and polarity of (I) and the absolute configuration of (II) were determined by refinement. The crystalline contents of (I) to (III) consist of infinite strings of hydrogen bonded cations, the counter ions and (where relevant) waters of crystallization acting as a hydrogen-bonding glue linking the spiral strings

In (II), the N-CH₂-CH₂-NH₂-Co rings of Co(1) are (δδλ) and those of Co(2) are (λλδ) and adjacent strings are linked by the counter-anions and the water of crystallization. Pairs of Co(1) and of Co(2) cations are hydrogen bonded to one another by two N-O···H-N linkages. Finally, pairs of composition Co(1)-Co(1) as well as of Co(2)-Co(2) share another pseudo-inversion center which is approximately valid for the CoN₆ portion of each cation. Since the atoms of the cation are ordered, it is impossible for the pseudo-inversion center to be valid for the -CH₂-CH₂- fragment of the Co(1)-Co(1) or of Co(2)-Co(2) pairs. (I) and (III) crystallizes as racemates whose five-membered rings have chiroptical symbols (δδλ), or its enantiomer.     

Crystal and molecular structure of [N,N-bis(2-carbamoylethyl)aminoacetato](imidazole)copper(II) perchlorate monohydrate, [Cu(Bcegly)(Im)](ClO4) · H2O

The [Cu(Bcegly)(Im)](ClO₄) · H₂O aminocarboxylate, where HBcegly is N,N-bis(2-carbamoyl-ethyl)aminoacetic acid and Im is imidazole, is studied by X-ray diffraction. The polyhedron of the Cu atom is an asymmetrically elongated tetragonal bipyramid (4 + 1 + 1), whose equatorial plane is composed of two oxygen atoms (average Cu-O, 1.952 ?) and a nitrogen atom (Cu-N, 2.031 ?) of the Bcegly^? ligand and the nitrogen atom of the Im ligand (Cu-N, 1.970 ?) and the axial positions are occupied by oxygen atoms of the Bceglyligand (Cu-O, 2.357 ?) and the perchlorate ion (Cu-O, 2.830 ?). The Bcegly^? ligand fulfils the tetradentate chelate function closing three metallocycles, namely, two six-membered CuNC₃O cycles and one five-membered CuNC₂O cycle. Complex cations, ClO ₄ ^? anions, and crystallization water molecules are connected by an extended system of hydrogen bonds.     

Iron salts with the tetracyanidoborate anion: [Fe(III)(H2O)6][B(CN)4]3, coordination polymer [Fe(II)(H2O)2{κ2N[B(CN)4]}2], and [Fe(II)(DMF)6][B(CN)4]2

The reaction of Fe(OH)(3) with tetracyanidoboronic acid, H[B(CN)(4)]·xH(2)O, in water leads to the first examples of tetracyanidoborates with a triply charged metal cation, [Fe(III)(H(2)O)(6)][B(CN)(4)](3) (1). Using elemental iron powder as starting material, [Fe(II)(H(2)O)(2){κ(2)ΝB(CN)(4)]}(2)] (2) is obtained. Anhydrous iron(II) tetracyanidoborate, which is synthesized by heating of 2, is soluble in dry dimethylformamide. After evaporation of the DMF solvent, single crystals of the third title compound, [Fe(II)(DMF)(6)][B(CN)(4)](2) (3), are obtained. Compound 3 is the first metal tetracyanidoborate soluble in nonpolar solvents. The title compounds have been characterized by single-crystal X-ray diffraction (1 rhombohedral, R3c (no. 167), a = 14.9017(7) ?, c = 20.486(1) ?, Z = 6; 2 tetragonal, I42d (no. 122), a = 12.3662(3) ?, c = 9.2066(4) ?, Z = 4; 3 triclinic, P1 (no. 2), a = 8.6255(3) ?, b = 11.0544(4) ?, c = 12.2377(5) ?, Z = 1). The metal ions in all three compounds are octahedrally coordinated. Whereas 1 and 3 are built up from isolated complex ions, 2 comprises a coordination polymer, in which the Fe(II) ion is coordinated by two oxygen atoms of two water molecules in a trans orientation and four nitrogen donor atoms of the [B(CN)(4)](-) groups, which bridge between neighboring iron ions. The iron(III) ion in 3 is in a perfect octahedral environment, which is formed by the O atoms of 6 molecules of water. The single-crystal X-ray structures, vibrational spectra, thermal properties, solubilities, and electrochemical characteristics are reported and compared with those of other known tetracyanidoborates.     

Different coordination patterns for two related unsymmetrical compartmental ligands: crystal structures and IR analysis of [Cu(C21H21O2N3)(OH2)(ClO4)]ClO4·2H2O and [Zn2(C22H21O3N2)(C22H20O3N2)]ClO4

The crystal structures of the new complexes [Cu(HL1)(OH₂)(ClO₄)]ClO₄·2H₂O (1) and [Zn₂(HL2)(L2)]ClO₄ (2), derived from two related, phenol-based compartmental ligands, are described. Compound 2 constitutes the first report of a complex obtained from H₂L2. The metal compounds are structurally different; 2 is a dimer in which all the heteroatoms of the ligand take part in coordination, while 1 is mononuclear containing a pair of cis-oriented ligands that complete an “open” coordination sphere, in which the aldehyde group of HL1 is not involved. The protonation status of the central phenol groups of HL1 and H₂L2 are also dissimilar between the complexes. Infrared vibrational analyses of both complexes, as well as their respective ligands, were performed to connect the observed spectral features with the structural properties of the solids. While some distinctive bands shifted upon complexation, it was not possible to confirm involvement of the aromatic aldehyde group in coordination by this technique. ¹H NMR experiments involving 2 suggest that its particular protonation status is maintained upon dissolution in d₆-DMSO.     

Synthesis,characterization, and catalytic activity of a water soluble copper(II) and nickel(II) heterobimetallic complex [CuNi(μ-OH)(μ-OH2)(μ-OAc)(bpy)2](ClO4)2 in aqueous medium in the absence of a base and co-catalyst

A copper(II)–nickel(II)-based catalyst system has been synthesized and characterized by elemental analysis, molar conductance, mass spectra, magnetic moment, EPR, UV-Vis, IR spectroscopy, and cyclic voltammetry. The structure of the complex was established by X-ray crystallography. The complex is an efficient catalyst, which oxidizes primary and secondary alcohols to the corresponding aldehydes and ketones at 70 °C employing 15% H₂O₂ as the oxidant in the absence of a base and co-catalyst.     

[Cu(L-Ile)(Phen)(H2O)(ClO4)]的合成、结构及稳定性研究

合成了三元混配配合物[Cu(L-Ile)(Phen)(H20)(ClO4)](L-Ile=L-异亮氨酸,phen=1,10-邻菲咯啉),通过红外光谱、紫外-可见光谱、摩尔电导率、X射线单晶结构分析,对配合物进行了表征.该晶体属单斜晶系,P21空间群,晶胞参数:a=1.1704(5)nm,b=0.8090(5)nm,c=2.1822(5)nm,β=98.061(5)°,Z=2,Dx=1.60Mg·m-3,R1=0.0462,wR2=0.1225.每个配合物分子中Cu(Ⅱ)离子与一个L-Ile(N,O)配体、一个Phen(N,N)配体、一个H2O(O)配体及一个ClO4-(O)形成六配位的畸变八面体构型.本文还用电位滴定法测定了配合物的稳定常数,结果表明,配合物具有高的稳定性.     

Crystal structure of barium α-(Ethylenediamine-N,N-diacetato)malonatocobaltate(III) perchlorate pentahydrate Ba[Co(Edda)(Mal)(ClO4) · 5H2O

The crystal structure of [Co (Edda)(Mal)](ClO₄) · 5H₂O is determined by X-ray diffraction analysis (the crystals are triclinic: a = 10.1363(12) Å, b = 11.0801(13) Å, c = 11.3173(13) Å, α = 101.129(13)°, β = 108.594(13)°, γ = 112.883(13)°, Z = 2, space group P $\overline 1 $ ). The Co³⁺ ion coordinates two O atoms of the malonate ion, as well as two N atoms and two trans-O atoms of the ethylene-N,N-diacetate ion. The [(H₂O)₄Ba(ClO₄)]⁺ subunits interact with the [Co(Edda)(Mal)]^? complexes to form infinite ribbons, and each complex is bonded with three Ba atoms through the O atoms of the carboxyl groups. The coordination number of the Ba atom is nine (four O atoms of the water molecule, one O atom of the perchlorate ion, and four O atoms of three adjacent complexes).     

Raman light scattering,infrared absorption and neutron scattering studies of the phase transition and reorientational dynamics of H2O ligands and ClO4↙ anions in [Ca(H2O)4](ClO4)2

Vibrational-reorientational dynamics of H₂O ligands and ClO₄^↙ anions in the high-, intermediate- and low-temperature phases of [Ca(H₂O)₄](ClO₄)₂, detected previously by differential scanning calorimetry (DSC) method, were investigated. The following experimental methods were applied to achieve the goal: middle-infrared (FT-MIR), Raman spectroscopy (RS) and inelastic incoherent neutron scattering (IINS). FT-MIR and RS spectra versus temperature show distinct changes in full-width-at-half-maximum (FWHM) of some bands connected with vibrational modes of ClO₄^↙ and [Ca(H₂O)₄]²⁺ ions. It suggests that in the high temperature phase these ions (and also the ligands from complex cation) perform fast (picoseconds correlation time scale, which is characteristic for optical spectroscopy) stochastic reorientational motions, however in the lower temperatures the speed of these motions is slowed down. Moreover, the splitting of some bands accompanying the observed phase transitions. The comparison of the results obtained by these complementary methods was made. Additionally, IR, RS and IINS spectra were calculated by the DFT method and an excellent agreement with the experimental data was obtained using CASTEP plane-wave periodic boundary condition code. The bands were assigned based on analysis of the phonon eigenvectors obtained from CASTEP calculations.