Synthesis and characterization of di- and tri-organotin(IV) complexes with Schiff base ligand pyruvic acid 3-hydroxy-2-naphthoyl hydrazone

A series of organotin(IV) complexes with Schiff base ligand pyruvic acid 3-hydroxy-2-naphthoyl hydrazone [R₂SnLY]₂, L = 3-HO-C₁₀H₆-2-CONHNC(CH₃)COOH, R = n-C₄H₉, Y = CH₃OH (1), R = n-C₄H₉, Y = N (2), R = PhCH₂ (3), R = Ph, Y = CH₃OH (4), R = Me, (5) and [R₃SnLY], L = 3-HO-C₁₀H₆-2-CONHNC(CH₃)COOH, R = n-C₄H₉, Y = H₂O, (6), R = Ph (7), R = Me (8) have been synthesized. These complexes have been characterized by elemental analysis, IR, ¹H and ¹¹⁹Sn NMR spectra. The crystal and molecular structure of complexes 1, 2 and 6 have been determined by X-ray single crystal diffraction. Results showed that complex 1 has a dimeric structure and the central tin atom is rendered seven-coordinate in a distorted pentagonal-bipyramid configuration. The complex 2 has a monoclinic structure and the central tin atom is rendered six-coordinate in octahedrally configuration with a planar of SnO₃N unit and two apical aryl C atoms. And the whole structure consists of molecular units connected by weak intermolecular Sn?N and O-H?N interactions. In the complex 6, the central tin atom is five-coordinate in distorted trigonal-bipyramidal geometry.     

Ni(II) coordination compounds based on mixed phthalate and aromatic amine ligands: synthesis, crystal structures and magnetic properties

Three new coordination compounds, [Ni(Pht)(Py)₂(H₂O)₃] (1), [Ni(Pht)(β- Pic)₂(H₂O)₃] · H₂O (2) and [Ni(Pht)(1-MeIm)₂(H₂O)₃] (3) (where Pht²⁻ = dianion of o-phthalic acid; Py = pyridine, β-Pic = 3-methylpyridine, 1-MeIm = 1-methylimidazole), have been synthesized and characterized by IR spectroscopy and thermogravimetric analysis. Crystallographic studies 1-3 reveal that each Ni(II) center has a distorted octahedral geometry being coordinated by two nitrogen atoms of aromatic amines, one oxygen atom from a carboxylate group of a phthalate ligand and three water molecules. Pht²⁻ anions act as monodentate ligands, while the remaining uncoordinated carboxylate oxygen atoms participate in the formation of hydrogen bonding. The uncoordinated oxygen atoms form hydrogen bonds with the coordinated water molecules from adjacent complexes creating a centrosymmetric dimer unit. Further, these dimer units are connected by O-H?O hydrogen bonds in double-chains. Depending on the nature of aromatic amines, the arrangement of these double-chains differs. The double-chains are held together only by van der Waals interactions in 1. In contrast, in 2 these chains form layers by π-π interactions between antiparallel molecules of β-Pic as well as by π-π interactions between β-Pic and Pht aromatic rings. In complex 3, the double-chains are knitted together via C-H?O hydrogen bonds between the methyl group of 1-MeIm and the coordinated carboxylate oxygen atom of Pht, as well as π-π contacts involving antiparallel 1-MeIm cycles. The thermal dependence of the magnetic susceptibilities for compounds 1 and 2 shows a weak antiferromagnetic interaction between the two Ni²⁺ ions of the hydrogen bonded dimers. For compound 3, a ferromagnetic interaction could be observed. Modeling the experimental data with MAGPACK resulted in: g = 2.22, |D| = 4.11 cm⁻¹ and J = −0.29 cm⁻¹ for compound 1, g = 2.215, |D| = 3.85 cm⁻¹ and J = −0.1 cm⁻¹ for compound 2 and g = 2.23, |D| = 4.6 cm⁻¹ and J = 0.22 cm⁻¹ for compound 3.     

Construction of three low dimensional Zn(II) complexes based on different organic-carboxylic acids

Three new Zn(II) complexes based on different organic-carboxylic acids, [Zn(mba)₂(2,2′-bipy)] (1), [Zn(mpdaH)₂(H₂O)₄] · 4H₂O (2) and [Zn(cda)₂(H₂O)₂]_n (3) (Hmba = 4-methylbenzoic acid, H₂mpda = 2,6-dimethylpyridine-3,5-dicarboxylic acid and H₂cda = chelidonic acid) have been synthesized successfully under hydrothermal conditions. X-ray single crystal diffractions show that compounds 1 and 2 are the mononuclear and 3 is one-dimensional chain, in which the Zn(II) centers have different coordination geometries with octahedron for 1 and 2 and tetrahedron for 3. Through π-π stacking and/or hydrogen bonding (O-H?O and O-H?N) interactions, different supramolecular structures are assembled, namely, 2D supramolecular layer for 1 and 3D supramolecular networks for 2 and 3. Furthermore, the IR, TGA and luminescent properties are also investigated in this work.     

The structural chemistry of triorganotin(IV) derivatives of 3-amino-5-mercapto-1,2,4-triazole: Supramolecular structures involving intermolecular N-H?N and N-H?S hydrogen bonding

Four new triorganotin complexes of 3-amino-5-mercapto-1,2,4-triazole with the type of R₃Sn(SC₂N₃HNH₂-3) (R = Me, 1; n-Bu, 2; Ph, 3; PhCH₂, 4) have been synthesized. All the complexes have been characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectra. Complexes 1, 3 and 4 have been characterized by X-ray crystallography analyses too. The geometry about Sn of complex 1 is distorted trigonal bipyramidal and the supramolecular structures of complex 1 has been found consist of channels built up by intermolecular N-H?N hydrogen bonding. The geometry of tin atoms in complexes 3 and 4 are distorted tetrahedron and 1D polymers connected by intermolecular N-H?N hydrogen bonding or N-H?N and N-H?S hydrogen bonding. Additionally, 1D polymer of complex 3 aggregated in 2D layer by intermolecular N-H?S hydrogen bonding.     

Structural and magnetic diversity in metal-dicyanamido polymer moieties: Paramagnetic and antiferromagnetic 1D chain compound and weakly ferromagnetic 2D motif

The reaction of M(NO₃)₂·xH₂O (M = Cu, Ni and Co; x = 3 for Cu and x = 6 for Co/Ni), imidazole (Im) and sodium dicyanamide (dca) afforded the complexes [M(Im)₂(dca)₂] (where M = Cu for 1, M = Ni for 2, and M = Co for 3). All of them have been characterized structurally by single crystal X-ray diffraction measurements. X-ray analysis reveals that the dicyanamido ligand features the μ_1,3 bridging mode that led to the formation of two-dimensional structure of complex 1 while complexes 2 and 3 attribute an infinite one-dimensional chain like structure to generate the fascinating molecular assemblies. The {N(CN)₂}⁻ ligands present in the complexes 2 and 3 are coordinated in end-to-end (μ_1,5) fashion. All the complexes have distorted octahedral geometry around the central metal ion and coordinated by two amine nitrogen atoms from imidazole ligands and four nitrogen atoms from dca ligands. The variable temperature (2-300 K) magnetic susceptibility measurements showed that the magnetic interaction between the metal centers in the complex 1 is dominantly ferromagnetic while the metal ions in complex 3 are antiferromagnetically coupled. On the contrary, complex 2 is a simple paramagnet. The results of magnetic model are in good agreement with the experimental data.     

2D network coordination polymers of lanthanide with N-(2-pyridylmethyl)iminodiacetic acid: Hydrothermal syntheses, crystal structures and luminescent properties

Six lanthanide two-dimensional network coordination polymers with the general formula of [Ln(pmida)(NO₃)(H₂O)]_n, where Ln = La (1), Nd (2), Sm (3), Gd (4), Dy (5), Er (6) and pmida²⁻ = N-(2-pyridylmethyl)iminodiacetate, have been synthesized by hydrothermal process and characterized by elemental analysis, Infrared spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. All crystals are isostructural and crystallize in the monoclinic space group P2₁/a. The lanthanide(III) ion is nine-coordinated in a geometry of distorted tricapped trigonal prism by two N atoms and two O atoms from one pmida²⁻ ligand, two bridging carboxylate O atoms from other two pmida²⁻ ligands, two O atoms of a bidentate chelating nitrate and a O atom of a coordinated water molecule. The luminescent properties of [Sm(pmida)(NO₃)(H₂O)]_n (3) and [Dy(pmida)(NO₃)(H₂O)]_n (5) were investigated.     

Coordination polymers of manganese(II) and cobalt(II) of a flexible tetradentate pyridine amide ligand: 1D zigzag network and non-covalent interactions

Synthesis and crystal structure of two coordination polymers of composition [Mn^II(H₂bpbn)_1.5][ClO₄]₂ · 2MeOH · 2H₂O (1) and [Co^II(H₂bpbn)(H₂O)₂]Cl₂ · H₂O (2) [H₂bpbn = N,N′-bis(2-pyridinecarboxamido)-1,4-butane], formed from the reaction between [Mn(H₂O)₆][ClO₄]₂/CoCl₂ · 4H₂O with H₂bpbn in MeCN, are described. In 1 each Mn^II ion is surrounded by three pyridine amide units, providing three pyridine nitrogen and three amide oxygen donors. Each Mn^II center in 1 has distorted MnN₃O₃ coordination. In 2 each Co^II ion is coordinated by two pyridine amide moieties in the equatorial plane and two water molecules provide coordination in the axial positions. Thus, the metal center in 2 has trans-octahedral geometry. In both 1 and 2, the existence of 1D zigzag network structure has been revealed. Owing to π-π stacking of pyridine rings from adjacent layers 1 forms 2D network; 2 forms 2D and 3D network assemblies via N-H?Cl and O-H?Cl secondary interactions. Both the metal centers are high-spin.     

Stereospecific interactions between dinuclear complex cations involving square-planar [Pt(II)(μ-S)2(bpy)] (bpy = 2,2′-bipyridine) frameworks derived from optically active octahedral Co(III) units with d- or l-penicillaminates

The reaction of the octahedral mononuclear complex, trans(N)-[Co(l-pen-N,O,S)₂]⁻ (pen = penicillaminate), with [PtCl₂(bpy)] (bpy = 2,2′-bipyridine) stereoselectively gave an optically active S-bridged dinuclear complex, [Pt(bpy){Co(l-pen)₂}]Cl · 3H₂O (2Cl · 3H₂O), whose structure is enantiomeric to the previously reported [Pt(bpy){Co(d-pen)₂}]Cl · 3H₂O (1Cl · 3H₂O). The mixture of equimolar amounts of 1Cl · 3H₂O and 2Cl · 3H₂O in H₂O crystallizes as [Pt(bpy){Co(d-pen)₂}]_0.5[Pt(bpy){Co(l-pen)₂}]_0.5Cl · 7H₂O (3Cl · 7H₂O), in which the enantiomeric complex cations 1 and 2 are included in the ratio of 1:1. The crystal structures of 2Cl · 3H₂O and 3Cl · 7H₂O were determined by X-ray crystallography, and compared with that of 1Cl · 3H₂O. The structural feature for 2 is essentially consistent with that for 1, except for the absolute configurations around the octahedral Co(III) center. The optically active complex cation 2 exists as a monomer, accompanied by no intermolecular interactions in the π-electronic systems of bpy moieties. In the crystals of 3Cl · 7H₂O, on the other hand, the enantiomeric complex cations, [Pt(bpy){Co(d-pen)₂}]⁺ and [Pt(bpy){Co(l-pen)₂}]⁺, are arranged alternately while overlapping the bpy planes along a axis, and the π electronic system of the bpy framework in [Pt(bpy){Co(d-pen)₂}]⁺ interacts with those in [Pt(bpy){Co(l-pen)₂}]⁺. Differences between the crystal structures of 2Cl · 3H₂O and3Cl · 7H₂O significantly reflect their diffuse reflectance spectra. In aqueous solution, each cation in both 2Cl · 3H₂O and 3Cl · 7H₂O is comparatively put on a free environment without such intermolecular interactions.     

Five-coordinate cobalt(II) complexes of tris(2-pyridylmethyl)amine (TPA): Synthesis, structural and magnetic characterization of a terephthalato-bridged dinuclear cobalt(II) complex

The cobalt(II) complexes [Co(TPA)Cl]ClO₄ (1), [Co(TPA)Br]ClO₄ (2), [Co(TPA)(H₂O)]Cl(ClO₄) (3) and [Co₂(TPA)₂(μ-tp)](ClO₄)₂ · 2H₂O (4) (TPA = tris(2-methylpyridyl)amine and tp = terephthalate dianion) were synthesized and structurally characterized by UV-vis and IR spectroscopy. The molecular structures of complexes 1 and 4 were determined by X-ray crystallography and their magnetic properties were measured over the temperature range 2-300 K. The coordination geometry around the central Co(II) in these compounds has a distorted trigonal bipyamidal geometry with four nitrogen atoms from the TPA ligand and the fifth coordination site is occupied by Cl⁻ ion in 1, Br⁻ ion in 2, coordinated oxygen atom from H₂O in 3 and by an oxygen atom supplied by the carboxylate group of the bridged terephthalato ligand in 4. The visible spectra of the complexes 1-3 in MeOH show strong distortion toward tetrahedral geometry. For complex 4, analysis of the infrared spectral data for the ν(COO⁻) stretching frequencies of the tp-carboxalato groups reveals the existence of the bis(monodentate) coordination mode for the bridged tp. X-ray data for 1 and 4 show that the former is mononuclear while the latter is dinuclear. The electronic spectrum of 4 in MeOH is in complete agreement with the assigned X-ray geometry around the Co(II) centers. The magnetic behavior of the mononuclear complex 1 is indicative of a high-spin compound with zero-field splitting. The best fit was obtained with ∣D∣ = 7.3 cm⁻¹, g = 2.25. The dinuclear complex 4 exhibits weak antiferromagnetic coupling with a coupling constant J = −0.8 cm⁻¹. The magnetic properties and the structural parameters of 4 are discussed in relation to the other related μ-terephthalato dinuclear Co(II) compounds. The geometry of the coordination sphere around 4 is unique - the CSD compilation listing only one other compound with such a geometry around the dinuclear Co(II) complex and its composition is far different from that in 4. However, they share a common feature of having a weakly antiferromagnetic coupling between Co(II) centers.     

Synthesis and crystal structure of a novel three-dimensional supramolecular network containing one-dimensional honeycomb-like channels

A novel supramolecular assembly containing honeycomb-like channels [Cu(mal)(bpy)] · 3H₂O (mal = malate, bpy = 2,2′-bipy) has been synthesized and characterized by elemental analyses, IR, EPR, TG, UV-Vis and single crystal X-ray diffraction. Compound 1 is constructed from spiral-shaped chains via O-H?O hydrogen bonds and π-π stacking interactions. To our knowledge, compound 1 represents the first supramolecular network constructed from the mixed malate and pyridine ligand.     

Syntheses, structures, and photoluminescent properties of four d metal-quinolinato coordination polymers with similar rod-like SBUs

Four M^II quinolinato complexes, [Zn₂(quin)₂(H₂O)₃]_n (1), [Zn(quin)(H₂O)₂]_n (2), [Zn(quin)(H₂O)]_n (3) and [Cd(quin)]_n (4) (H₂quin = 2,3-pyridinedicarboxylic acid or quinolinic acid), have been hydrothermally synthesized and structurally characterized. X-ray diffraction analyses reveal that all of these four complexes are constructed from similar rod-like SBUs, [M(quin)]_n (M = Zn or Cd). Complexes 1 and 2 have similar 1-D box-like chains but different packing structures; complex 3 has a 2-D grid-like network and complex 4 has an unusual 2-D bilayer structure. Due to the different structural features, these complexes exhibit different photoluminescent emissions: complex 1 at 439 nm (λ_ex = 345 nm), complex 2 at 428 nm (λ_ex = 360 nm), complex 3 at 508 nm (λ_ex = 304 nm) and complex 4 at 500 nm (λ_ex = 324 nm).     

Hydrogen bonding adducts of octamolybdate anions containing coordinately bound pyridiniumoxides

The reaction of [Mo₇O₂₄][NH₄]₆ with 3-hydroxypyridine (3-HOPy) and 4-hydroxypyridine (4-HOPy) in water resulted in the crystalline materials of [Mo₈O₂₆(3-OPyH)₂][3-HOPyH]₄ · 4H₂O (1) and [Mo₈O₂₆(4-OPyH)₂][4-HOPyH]₄ · 4H₂O (2), respectively. Crystal structures of the complexes 1 and 2 reveal that two of the OPyH moieties coordinately linked to two molybdate atoms of Mo₈O₂₆ clusters. The crystal structures of 1 and 2 are not iso-structural. However, in both cases the iso-structural Mo₈O₂₆(OPyH)₂ units join together via N-H?O hydrogen bonds to form linear ribbons which are further joined by H₂O molecules to form 2D-layers. The cavities or channels of these layers are occupied by the C-H?O, O-H?O and O-H?π aggregates of hydroxypyridinium cations.     

Further study of the effect of macrocyclic pendant groups on the supramolecular architecture: Synthesis and structures of macrocyclic nickel (II) complexes with trans-butene dicarboxylate

Two nickel (II) complexes with the formula [NiL(H₂O)₂] · 6H₂O (1 · 6H₂O) and [NiH₂L(BDC)]_n (2), where L = 3,10-bis(3-propylcarboxyl)-1,3,5,8,10,12-hexaazacyclo-tetradecane, BDC = trans-butene dicarboxylate, have been synthesized and characterized by elemental analyses, IR spectra and single-crystal X-ray analyses. In 1, the Ni(II) ion is six-coordinated with four nitrogen atoms from the macrocyclic ligand in the equatorial plane and two water molecules in axial position. In 2, the structure is made up of one-dimensional chain of [NiH₂L]²⁺ units with BDC²⁻ anions, in which the Ni(II) ion is also six-coordinated with four nitrogen atoms from the macrocyclic ligand in the equatorial plane and two carboxylate oxygen atoms from the BDC²⁻ group in axial position. In 2, the 1D chains are aligned in a parallel mode.     

Synthesis, spectral and magnetic properties and crystal structures of copper(II) pyridinecarboxylates as potential antimicrobial agents

Synthesis and characterization of six new complexes [Cu{2,6-(MeO)₂nic}₂(H₂O)]₂ (1), [Cu{2,6-(MeO)₂nic}₂(H₂O)]₂ · 3DMF (2), where 2,6-(MeO)₂nic is 2,6-dimethoxynicotinate and DMF is N,N-dimethylformamide, [Cu(3-pyacr)₂(H₂O)₂]_n (3), where 3-pyacr is trans-3-(3-pyridyl)acrylate, [Cu(en)₂(H₂O)₂]X₂, where X is 2,6-(MeO)₂nic (4) or 3-pyacr (5) and en is ethylenediamine, and [Cu(3-pyacr)₂(dien)(μ-H₂O)_0.5]₂ · 7H₂O (6), where dien is diethylenetriamine are reported. The characterizations were based on elemental analysis, infrared, electronic and EPR spectra, and magnetic measurements over a temperature range of 1.8-300 K. Crystal structures of complexes 2, 4 and 6 have been determined by X-ray single crystal structure analysis. The available evidence supports dimeric structure of the acetate type for 1 and 2. Crystal structure of polymeric complex 3 has been determined from X-ray powder diffraction data. The 3-pyacr anions in pairs form bridges between two octahedrally surrounded copper(II) atoms in such a way that one 3-pyacr is coordinated to the first Cu^II by an oxygen atom of its carboxyl group and to the second Cu^II by the nitrogen atom of its pyridine ring, while the other is coordinated to the same two Cu^II atoms in a similar way, but the other way round. Environment about the copper(II) atom for 4 and 5 is a square bipyramid (4+2).In complex 6 both Cu^II central atoms are bridged only by an axial water molecule forming a dimeric structure with the considerably long separation of Cu^II atoms of 5.194 Å and the angle Cu1-O3-Cu1a of 150.79°. Moreover, results of the quantitative determination of antimicrobial activity of the complexes as well as above organic ligands alone are discussed.     

Palladium(II) complexes obtained from 3,4-bis(cyanamido)cyclobutane-1,2-dione dianion

Three palladium(II) complexes have been synthesized, using 3,4-bis(cyanamido) cyclobutane-1,2-dione dianion (3,4-bis(cyanamido)squarate or 3,4-NCNsq²⁻): [Pd(en)(3,4-NCNsq)] · 1.5H₂O (1) (en=1,2-diaminoethane), [Pd(en)(3,4-(NC(O)NH₂)sq)] · 0.5H₂O (2) and K₃Na[Pd₂(3,4-(NCN)₂sq)₄] · 5H₂O (3). Complex 1 has been characterized by elemental analysis, IR and ¹³C NMR spectroscopies. Complexes 2 and 3 have been characterized by single-crystal X-ray diffraction. In complex 2, the unusual hydration of the cyanamido ligand was observed, it proceeds in the coordination sphere of the palladium and leads to a chelating urea squarate ligand. Complex 3 is an anionic dinuclear complex containing four bridging cyanamido squarate ligands. In complexes 2 and 3, the 3,4-NCNsq²⁻ ligand (hydrated or not) is, for the first time, coordinated to the metal atom by the two amido nitrogen atoms, either in a chelating mode (complex 2) or in a bridging mode giving a short Pd ? Pd distance of 2.8866(15) Å (complex 3). Electrochemical studies in acetonitrile and dmf solutions have been performed on complexes 1 and 3.     

Synthesis, characterizations and crystal structures of antimony(III) complexes with nitrogen-containing ligands

Six antimony adducts with N-donor neutral ligands (1,10-phenanthroline, 4,4′-bipyridine) have been obtained following the reaction of antimony halides with phenanthroline and 4,4′-bipyridine. By changing the solvent and stoichiometry, we obtained six different complexes, Sb(phen)Cl₃ (1), Sb(phen)Br₃ (2), Sb₂(phen)₄Br₈ (3) and Sb(bpy)Cl₃ (4), Sb(bpy)₂Cl₃ (5), Sb(bpyH · bpyH₂)Br₆ (6) (where phen = 1,10-phenanthroline, bpy = 4,4′-bipyridine). All the complexes have been characterized via elemental analysis, FT-IR and NMR (¹H, ¹³C) spectroscopy. The crystal structures of complexes 2, 3 and 6 have been determined by X-ray single crystal diffraction.The structural analysis show that the coordination sphere around antimony atom in complex 2 is a distorted square pyramid, coordinated by three bromine atoms and two nitrogen atoms from phen. In complex 3, the central antimony atom is six-coordinated through four bromine atoms and two nitrogen atoms forming a distorted octahedral geometry. Besides that, there are also uncoordinated 1,10-phenanthroline bonded by hydrogen bonds and π-π stacking interactions, which is rarely observed in previous reports. The crystal structure of complex 6 consists of bpyH · bpyH₂ trications and hexabromoantimonate trianions. The antimony atom in the anion has a distorted octahedral environment. Additionally, all complexes present a 3D framework built up by N-H?Br, C-H?Br and C-H?Cl weak hydrogen bonds interactions.     

Nickel(II)-, cobalt(II)-, copper(II)-, and zinc(II)-phthalate and 1-methylimidazole coordination compounds: synthesis, crystal structures and magnetic properties

Three new coordination polymers [M(Pht)(1-MeIm)₂]_n (where M=Cu (1), Zn (2), Co (3); Pht²⁻=dianion of o-phthalic acid; 1-MeIm=1-methylimidazole) and two compounds [M(1-MeIm)₆](HPht)₂ · 2H₂O (M=Co (4), Ni (5)) have been synthesized and characterized by X-ray crystallography. The structures of 1-3 (2 is isostructural to 3) consist of [M(1-MeIm)₂] building units connected by 1,6-bridging phthalate ions to form infinite chains. In complex 1, each copper(II) center adopts a square coordination mode of N₂O₂ type by two O atoms from different phthalate ions and two N atoms of 1-MeIm, whereas in 3 two independent metal atoms are tetrahedrally (N₂O₂) coordinated to a pair of Pht ligands and a pair of 1-MeIm molecules. There are only van der Waals interactions between the chains in 1, while the three-dimensional network in 3 is assembled by C-H?O contacts. In contrast to polymers 1-3 the structures of 4 and 5 (complexes are also isostructural) are made up of the [M(1-MeIm)₆]²⁺ cation, two hydrogen phthalate anions (HPht⁻) and two H₂O solvate molecules. The coordination around each metal(II) atom is octahedral with six nitrogen atoms of 1-MeIm. Extended hydrogen bonding networks embracing the solvate water molecules and a phthalate residue as well as the weak C-H?O interactions stabilize the three-dimensional structures. Magnetic studies clearly show that the magnetic ions do not interact with each other. Furthermore, in compound 4 we have another example of a highly anisotropic Co²⁺ ion with a rhombic g-tensor and large zero-field-splitting. The complexes were also characterized by IR and ¹H NMR spectroscopy, thermogravimetric analysis, and all data are discussed in the terms of known structures.     

Hydrothermal syntheses, crystal structures and characterizations of three new copper coordination polymers

Three new copper complexes, [Cu^IICu^I(ip)(ipH)(4,4′-bipy)_3/2]_n (1), [Cu(ip)(4,4′-bipy)]_n · 3nH₂O (2), and [Cu(ipH)₂(4,4′-bipy)]_n (3), have been hydrothermally synthesized by the reaction of Cu(NO₃)₂ · 3H₂O with isophthalic acid (ipH₂) and 4,4′-bipyridine (4,4′-bipy) under different reaction conditions. Complex 1, a mixed-valence copper(I,II) complex, exhibits a 2-D interpenetrating grid framework, in which five-coordinated Cu^II and three-coordinated Cu^I environments are established. The oxidation states of center Cu atoms have been confirmed by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance spectra (EPR). Complex 2 features a 2-D box-like bilayer architecture, in which Cu^II atoms are linked by ip ligands to form a 1-D double-chain and the resulting chains are further strutted by the 4,4′-bipy ligands. In complex 3, two bridging 4,4′-bipy ligands and two terminal ipH ligands confine the Cu^II center in a square plane coordination geometry. The whole molecule of 3 was arranged into a 1-D linear chain structure. Additionally, the thermogravimetric analyses (TGA) for complexes 1-3 are also discussed in this paper.     

Synthesis, structural investigation and thermal stability of aqua magnesium(II) phthalocyanine adducts with 2-methoxyethylamine

Three new aqua magnesium phthalocyaninato complexes with 2-methoxyethylamine (MEA) in crystalline form have been obtained. The composition of the complexes depends on the crystallisation temperature. (MgPcH₂O)₂ · MEA (I) and (MgPcH₂O)₂ · 2MEA (II) were formed at about 170 °C and 80 °C, respectively, while room temperature (MgPcH₂O)₂ · 3MEA (III) was obtained. In all crystals the Mg atom is 4+1 coordinated, equatorially by four N-isoindole atoms of Pc ligand and axially by O atom of water molecule. The MgPc moiety is non-planar, the Mg(II) deviates by ∼0.5 Å from the N₄-isoindole plane towards the oxygen atom of water molecule. The MEA molecules in the crystals interact via hydrogen bonds with coordinated water molecules of MgPcH₂O. The arrangement of MgPcH₂O and 2-methoxyethylamine molecules is determined by O-H?N and O-H?O hydrogen bonds and by π-π interactions. The thermogravimetric analyses show characteristic steeps responsible for the loss of MEA molecules (at lower temperature) and water (at higher temperature) and finally all the complexes transform into β-MgPc. From among the complexes only complex II exhibits an intense near-IR absorption band in the solid-state, while spectra in MEA solution are identical for all the complexes.     

Hexa-coordinated aluminum and gallium cations derived from indazole

trans-Dichloro-tetrakis-(indazole)aluminum(III) tetrachloroaluminate(III) 1 and trans-dichloro-tetrakis-(indazole)gallium(III) tetrachlorogallate(III) 3 were obtained by the asymmetric cleavage of the chloride-bridged dimers [AlCl₃]₂ and [GaCl₃]₂ with two moles of indazole and characterized by NMR, X-ray diffraction, EA and IR. The synthesis of 3[1] was improved (yield 86%) using methylene chloride at room temperature. The addition of THF to a solution of 1/CH₂Cl₂ afforded in good yield complex 2 {[AlCl₂(IndH)₄]⁺[AlCl₄]⁻·4THF}. The crystal structures of these complexes are monoclinic in the space groups P2(1)/n (1), C2/c (2) and P2(1)/n (3). The unit cells of 1-3 contain ion pairs [ECl₂(IndH)₄]⁺ [ECl₄]⁻ (E = Al and Ga) with multiple hydrogen interactions (Cl?H 2.434-2.925 Å, O?H 1.984-2.665 Å, C?H 2.769-2.888 Å). The [ECl₂(IndH)₄]⁺ cations show hexa-coordinated octahedral aluminum and gallium atoms with two chlorine atoms in anti positions and four coplanar nitrogen atoms from the indazole ligands. The [ECl₄]⁻ anions have a tetrahedral coordination geometry around the central atom. In the lattice, the presence of THF molecules simplifies the weak interactions network in 2, so one anion interacts with two [MCl₂(Ind-H)₄]⁺ cations and two THF molecules through Cl?H intermolecular interactions (2.855-2.922 Å) and one [MCl₂(Ind-H)₄]⁺ cation interacts with two cations through ClL₄MCl?H interactions (2.922 Å). Whereas in 1 and 3, six anions interact through Cl?H intermolecular interactions (2.795-2.925 Å) with one [MCl₂(Ind-H)₄]⁺ cation and this latter interacts with other three [MCl₂(Ind-H)₄]⁺ cations through C?H interactions (2.769-2.888 Å). Additionally, every chlorine atom in the [MCl₂(Ind-H)₄]⁺ cationic moieties is bounded by NCH?ClM or NH?ClM intramolecular-tetrafurcated hydrogen bonds (2.434-2.907 Å).