Mononuclear Molecules Research Articles

Pseudohalide manganese(II) complexes of 2-hydroxymethylbenzimidazole – Synthesis, spectroscopy, X-ray structure and magnetic properties

Three new manganese(II) complexes of 2-hydroxymethylbenzimidazole [Mn(hmbzim)2(NCS)2] (1), [Mn2(hmbzim)4(μ1,1-N3)2](NO3)2 (2) and [Mn(hmbzim)2(dca)2]n (3) were synthesized and characterised. On the basis of structural data, the influence of pseudohalide ions on a final complex structure and role of weak intermolecular interactions in creation of molecular architecture have been discussed. The structure 1 consists of the mononuclear molecules [Mn(hmbzim)2(NCS)2] assembled via O–H⋯S and N–H⋯S hydrogen bonds into three dimensional supramolecular network The reaction with using of sodium azide resulted in formation of 0D dimeric structure of 2, whereas the complex 3 incorporating dicyanamide ions displays two-dimensional coordination framework. Magnetic measurements revealed ferromagnetic coupling (J=0.82(1)cm−1) inside the dimer of 2 and weak antiferromagnetic coupling (J=−0.37(1) cm−1) in 2D lattice of 3. The complex 1 indicated a very small antiferromagnetic interaction between MnII ions transmitted in the crystal lattice.

2,5-Bis(2,2'-bipyridyl-6-yl)-3,4-diazahexa-2,4-diene]dichloridomanganese(II): from a mononuclear compound to a three-dimensional supramolecular framework through C-H···Cl hydrogen bonds and π-π stacking interactions.

The title compound, [MnCl2(C24H20N6)], has been synthesized and characterized based on the multifunctional ligand 2,5-bis(2,2'-bipyridyl-6-yl)-3,4-diazahexa-2,4-diene (L). The Mn(II) centre is five-coordinate with an approximately square-pyramidal geometry. The L ligand acts as a tridendate chelating ligand. The mononuclear molecules are bridged into a one-dimensional chain by two C-H···Cl hydrogen bonds. These chains are assembled into a two-dimensional layer through π-π stacking interactions between adjacent uncoordinated bipyridyl groups. Furthermore, a three-dimensional supramolecular framework is attained through π-π stacking interactions between adjacent coordinated bipyridyl groups.

Synthesis, structure and photoluminescence of Zn(II) and Cd(II) complexes with pyridophenazine derivative

The [ZnLCl2] (1) and Cd2L2Cl4 (2) complexes, where L is ethyl 2-methyl-5-(prop-1-en-2-yl)pyrido[2,3-a]phenazine-3-carboxylate, were synthesized. The complexes were characterized by elemental analyses, 1H and 13C NMR spectroscopy, and X-ray powder diffraction. Single crystals of 1 and [Cd2L2Cl4]·4CH2Cl2 (3) have been grown. The structure of 1 consists of mononuclear molecules, while the structure of 3 is built up of centrosymmetrical binuclear [Cd2L2Cl4] complex molecules and uncoordinated CH2Cl2 molecules. In 1 and 3, L acts as a bidentate chelating ligand. There is five-membered ZnN2C2 chelate cycle in the [ZnLCl2] molecule. There are two five-membered CdN2C2 chelate cycles and a Cd2Cl2 dinuclear unit in the molecule of [Cd2L2Cl4]. The coordination polyhedra are distorted tetrahedron Cl2N2 (in the structure 1) and distorted tetragonal pyramid Cl3N2 (in the structure of 3). According to IR-spectroscopic data, complex 2 is binuclear. Complexes 1 and 2 display bright luminescence in CHCl3 solutions (λmax=477 and 475nm, respectively) and in the solid state (λmax=510 and 529nm, respectively). The free L ligand shows weak luminescence intensity (λmax=441 and 467nm in CHCl3 and solid state, respectively).

Role of C–H···Au and Aurophilic Supramolecular Interactions in Gold–Thione Complexes

The role of noncovalent gold–hydrogen and aurophilic interactions in the formation of extended molecular systems of gold complexes was studied. Three new gold compounds with a heterocyclic thione ligand N-methylbenzothiazole-2-thione (mbtt), namely, [AuCl(mbtt)] (1), [AuBr(mbtt)] (2), and [Au(mbtt)2][AuI2]1–n[I3]n (3), were synthesized and characterized. The halide ligand had a considerable effect on the complex structures and thus to noncovalent contacts. Intermolecular C–H···Au and aurophilic Au···Au contacts were the dominant noncovalent interactions in structures 1–3 determining the supramolecular arrays of the gold complexes. In 1 and 2, unusual intermolecular C–H···Au gold–hydrogen contacts linked the adjacent mononuclear molecules to a chain structure, while in 3 the change in the ligand coordination induced the formation of an intermolecular aurophilic interaction. Au···I, π–π, halogen–halogen, and hydrogen bonding interactions supported further the supramolecular array of 3. The interactions were...

Syntheses of two coordination polymers with rutile-type topology and the single-crystal-to-single-crystal transformation of Mg(ii) complex induced by methanol

Two isomorphous 3D frameworks with rutile topology based on isonicotinate, [Mn(IN)2]·H2O (1) and [Mg(IN)2]·H2O (2), were prepared. Compound 1 shows excellent stability in alcohols, while compound 2 reveals a rare single-crystal-to-single-crystal transformation from a 3D structure to a mononuclear molecule of [Mg(IN)2(CH3OH)4] (3) by soaking in methanol.

Synthesis, characterization, and X-ray crystal structures of copper(II) and nickel(II) complexes with Schiff base

New copper(II) complexes, [Cu2L1L2] · ClO4 (I) and [Ni(L3)2] (II), where L1 is the monoanionic form of 2-[1-(2-emthylaminoethylimino)ethyl]phenol, L2 is the dianionic form of N,N′-ethylene-bis(2-hydroxyacetophenonylideneimine), L3 is the mono-anionic form of 2-(1-iminoethyl)phenol, were prepared and characterized using elemental analysis, FT-IR spectroscopy, and X-ray single-crystal diffraction. In complex I, the Cu(1) atom is coordinated by the NNO tridentate ligand L1 and the two phenolate O atoms of L2, forming a square pyramidal geometry. The Cu(2) atom in complex I is coordinated by the NNOO tetradenate ligand L2, forming a square planar geometry. The Ni atom in complex II is coordinated by two phenolate O and two imine N atoms from two ligands L3, forming a square planar geometry. In the crystal structure of I, the perchlorate anions are linked to the dinuclear copper(II) complex cations through intermolecular N-H...O hydrogen bonds. In the crystal structure of II, the mononuclear nickel complex molecules are linked through intermolecular N-H...O hydrogen bonds, forming a trimer.

Syntheses and structures of N’-(5-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide and its dioxomolybdenum(VI) complex with catalytic epoxidation property

A new Schiff base N′-(5-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide (H2BMH) and its dioxomolybdenum(VI) complex [MoO2(BMH)(EtOH)] have been synthesized and characterized by elemental analysis, IR spectra, and single crystal X-ray determination. The Schiff base crystallized in the orthorhombic space group P212121 and the complex crystallized in the triclinic space group . The Schiff base coordinates to Mo through the phenolate O, imine N, and enolic O. The asymmetric unit of the complex contains two mononuclear dioxomolybdenum molecules. Each Mo is six-coordinate octahedral. The only significant difference between the complex and the ligand is the geometry involving donors. The coordination of the ligand to Mo is also reflected in the IR spectra. The complex shows high catalytic property and selectivity in epoxidation of cyclohexene with t-butylhydroperoxide as oxidant.

Synthesis of optically active Zn(II) complexes with thiosemicarbazones of (+)-camphor (L) and (−)-carvone (L1). The crystal structures of L and [Zn(L)2Cl2

The optically active complexes [Zn(L)2Cl2] (I) and [Zn(L1)2Cl2] (II) (L and L1 are thiosemicar-bazones of (+)-camphor and (−)-carvone, respectively) were obtained. The crystal structures of L and complex I were determined by X-ray diffraction. The structure of L consists of hydrogen-bonded molecules united into chains. The crystal structure of complex I is built from mononuclear molecules. The coordination polyhedron of the Zn atom is a distorted tetrahedron Cl2S2. The molecule L functions as a monodentate ligand. According to data from IR spectroscopy, complex II is structurally similar to complex I.

Time-of-diffusion dependent structural diversity in the MII-phen-tetracyanometalates (M = Zn, Mn) supramolecular system

The mononuclear molecules, ionic compounds and cyanide-based layers were isolated at different periods from one-pot crystallization in the MII-phen-tetracyanometalates (M=Zn, Mn) system, in which a time-of-diffusion dependent structural diversity was involved.

Synthesis and photoluminescence of the heteroligand Sm(III) complexes containing nitrogen heterocycles (Phen, 2,2′-Bipy) and anions C4H8NCS 2 − , iso-Bu2PS 2 − , (iso-PrO)2PS 2 − , and NO 3 − . Crystal structure of Sm(2,2′-Bipy)2(NO3)3

The photoluminescence spectra of the known complexes, Sm(L)2(NO3)3 (I, II), Sm(L)(iso-Bu2PS2)3 (III, IV), Sm(L)(iso-Bu2PS2)2(NO3) (V, VI) (L = Phen, 2,2′-Bipy), and Sm(Phen)(C4H8NCS2)3 (VIII), and new compounds, Sm(Phen)((iso-PrO)2PS2)3 (VII), Sm(2,2′-Bipy)(C4H8NCS2)3 · 0.5CH2Cl2 (IX), are obtained and interpreted. Using the X-ray structure analysis data, the crystal structure of the [Sm(2,2′-Bipy)2(NO3)3] complex (II) is determined. Structure II consists of discrete mononuclear molecules having a ten-vertex coordination polyhedron N4O6. The ligands 2,2′-Bipy and NO 3 − are bidentate-cyclic. The influence of the composition of the complexes on the photoluminescence (PL) intensity in the series I–VI is considered. The dependence of the intensity of the band with λmax = 647 nm in the PL spectra of complexes III, VII, and VIII on the type of the sulfur-containing ligand in their composition is established. The band intensity changes in the series VIII > III > VII.

Transition Metal Complexes with the Schiff Base Ligand 1‐{[2‐(2‐Hydroxyethylamino)ethylimino]methyl}naphthalen‐2‐ol

AbstractSix transition metal compounds [Cu(H2L)(CH3COO)]·H2O (1), [Cu(H2L)(CH3COO)] (2), [Cu(H2L)](ClO4)·CH3OH (3), 2[Cu(H2L)2] (4), [Co(H2L)2](NO3)·2CH3OH (5), and [Ni(H2L)](NO3) (6) were synthesized by reactions of the Schiff base ligand H3L (1‐{[2‐(2‐hydroxyethyl amino)ethylimino]methyl}naphthalen‐2‐ol) with the corresponding metal salts and characterized by single crystal X‐ray diffraction, elemental analysis, IR and UV/Vis spectroscopy and TG analysis. All compounds are mononuclear molecules, in which the Schiff base ligand exhibits diverse coordination modes and conformations. The N–H···O, O–H···O, and C–H···O inter‐ and intramolecular hydrogen bonding interactions link these molecules into multidimensional network supramolecular structures.

Synthesis, structures, and photoluminescence of heteroligand complexes Ln(L)(iso-Bu2PS2)2(NO3) (Ln = Sm, Tb, Dy; L = Phen, 2,2′-Bipy)

Heteroligand complexes Ln(L)(iso-Bu2PS2)2(NO3) (Ln = Sm, Tb, Dy; L = Phen, 2,2′-Bipy) (I–VI) are synthesized. The structure of Dy(Phen)(iso-Bu2PS2)2(NO3) (III) is determined from the data of X-ray structure analysis. The crystal structure of complex III is based on discrete mononuclear molecules in which the Dy atom has distorted dodecahedral coordination (polyhedron N2O2S4). The ligands Phen, iso-Bu2PS2− and NO3− are bidentate-cyclic. According to the X-ray diffraction analysis data, complexes I and II are isostructural to compound III. Complexes I–VI have photoluminescence in the visible spectral range. The photoluminescence spectra of solid samples of compounds I–VI exhibit bands corresponding to the radiative electron transitions of the Sm3+, Tb3+, and Dy3+ ions. Among the studied compounds I–VI, the Tb(III) complexes are characterized by the most intense photoluminescence.

Triaqua(cyclohex-4-ene-1,2-dicarboxylato-κO1)(1,10-phenanthroline-κ2N,N′)cobalt(II)

In the title compound, [Co(C8H8O4)(C12H8N2)(H2O)3], the CoII atom is coordinated by two N atoms from a bidentate 1,10-phenanthroline ligand, one O atom from a monodentate 4-cyclo­hexene-1,2-dicarboxyl­ate ligand and three water O atoms in a distorted octa­hedral geometry. The mononuclear mol­ecules are engaged in extensive intra- and inter­molecular O—H⋯O hydrogen-bonding inter­actions and π–π stacking inter­actions [centroid–centroid distance = 3.784 (3) Å], forming a three-dimensional supra­molecular network.

Hydrothermal Syntheses, Crystal Structures, and Fluorescent Properties of Zn(II) Coordination Complexes With 4-Amino-3,5-Bis(2-Pyridyl)-1,2,4-Triazole and Different Aromatic Dicarboxylic Acids

Three new Zn(II) supramolecular complexes {[Zn(2-bpt)(tp)(H2O)](H2O)}∞ (1), [Zn(2-bpt)2(Hpa)2] (2), and [Zn(2-bpt)2(H2O)2](Hip-NO2)2 (3) have been synthesized under hydrothermal conditions by using 4-amino-3,5-bis(2-pyridyl)- 1,2,4-triazole (2-bpt) and Zn(OAc)2 with the presence of different aromatic dicarboxylic acids (H2tp = terephthalic acid, H2pa = phthalic acid, and H2ip–NO2 = 5-nitroisophthalic acid). Complex 1 shows a one-dimensional zigzag chain array, 2 represents a neutral mononuclear molecule, and 3 consists of the cationic mononuclear coordination unit and Hip-NO2 anion. Notably, in complex 3, the H2ip–NO2 ligand is partly deprotonated to balance the charge and uncoordinated to the metal center. In all three structures, the low-dimensional coordination motifs are further extended to distinct two-dimensional or three-dimensional supramolecular networks via H-bonding and/or π···π stacking interactions. Fluorescent properties for 1–3 have also been studied in solid state at room temperature.

Hydrothermal Syntheses and Crystal Structures of Three Zn(II) Coordination Compounds Constructed with 3,5-Pyrazoledicarboxylic Acid

Three novel metal–organic coordination compounds, [Zn(Hdcp)(H2O)4]·1.5H2O (1), [Zn(Hdcp)(H2O)2]∞ (2) and [Zn3(dcp)2(H2O)5]∞ (3) with the ligand 3,5-pyrazoledicarboxylic acid were prepared by the hydrothermal method. The complexes were structurally characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. Compound 1 is a mononuclear molecule that is linked into a 3D supramolecular framework via N–H···O and O–H···O hydrogen bonds. In 2, two types of carboxylic bridges were found between ZnII ions to form a 1D double-chain. The 1D chains were further construct into a 3D structure by hydrogen bonds. Trinuclear 3 consists of 1D bi-infinite parallelogram chains of [Zn3(dcp)2(H2O)3] trimers. In the basic trinuclear unit a further bridging mode of the ligand is seen where two dcp3− ligands chelate three ZnII ions by utilizing five donors of the dcp3− ligand. The photoluminescent properties of 1, 2 and 3 were investigated.

Construction of monomers and chains assembled by 3d/4f metals and 4′-(4-carboxyphenyl)-2,2′:6′,2″-terpyridine

A series of transition metal and lanthanide complexes of 4′-(4-carboxyphenyl)-2,2′:6′,2″-terpyridine (HL, 1), namely [M(L)2]·5H2O (M=Ni, 2; Co, 3), [Zn(L)2]n·0.5nH2O (4) and [Ln(L)3]n (Ln=Nd, 5; Gd, 6; Er, 7) were hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Isomorphic compounds 2 and 3 are mononuclear molecules with two ligand chelating to the metal centers via tridentate terpyridyl, while compound 4 adopts 1D chain-like structure, in which five-coordinate zinc centers are surrounded by three ligands. Compounds 5–7 also display 1D chain-like structure, but the nine-coordinate lanthanide centers bonded by four ligands. Luminescent property indicates that compound 4 exhibits photoluminescence in the solid state at room temperature.

Crystal Structure and Thermal Behavior of Two New Supramolecular Complexes Templated with 1,2,4,5-Benzenetetracarboxylic Acid

Templated coordination polymers [Ni(H2O)4(bipy)](BTA)0.5·H2O (1) and [Co(H2O)4(bipy)](BTA)0.5·H2O (2) (bipy = 4,4′-Bipyridine, H4BTA = 1,2,4,5-Benzenetetracarboxylic Acid) were synthesized and characterized by single-crystal X-ray diffraction, powder diffraction, elemental analysis, IR, and thermogravimetric analysis. Both of complexes 1 and 2 are monoclinic crystal system, C2/c space group, and isostructural. The unit of the structure, the metal ion is coordinated by four water molecules and two bipy molecules, is a slightly distorted octahedral configuration, and the carboxyl group from BTA4- ion doesn't coordinate with the metal ion, the H-bonding interactions further connect the mononuclear molecules to generate a 3D supramolecular complex.

Bis(azido-κN)bis[6-(pyridin-2-yl)-1,3,5-triazine-2,4-diamine-κ2N1,N6]manganese(II)

In the title complex, [Mn(N3)2(C8H8N6)2], the complete molecule is generated by the application of twofold symmetry, and is in a distorted octa­hedral environment, coordinated by four N atoms of two bidentate 6-(pyridin-2-yl)-1,3,5-triazine-2,4-diamine ligands and two N atoms from two azide anions. The two chelated 6-(pyridin-2-yl)-1,3,5-triazine-2,4-diamine ligands form a dihedral angle 74.75 (5)°. The mononuclear mol­ecules are alternatively linked into layers parallel to the ac plane via N—H⋯N hydrogen bonds. Adjacent layers are connected into a three-dimensional supra­molecular framework by futher N—H⋯N hydrogen-bonding inter­actions.

Syntheses and structures of four copper(II) complexes constructed from m-ferrocenylbenzoate and N-donor ligands

A series of four m-ferrocenylbenzoate [m-ferrocenylbenzoate = Na(m-OOCH4C6Fc), Fc = (η5-C5H5)Fe(η5-C5H4)] copper(II) complexes Cu2(μ2-OOCH4C6Fc)4(CH3OH)2 (1), Cu(η2-OOCH4C6Fc)2(2,2′-bpy) (2), Cu(η2-OOCH4C6Fc)2(1,10-phen) (3) and [Cu(η2-OOCH4C6Fc)2(4,4′-bpy)]n (4) (bpy = bipyridine, 1,10-phen = 1,10-phenanthroline) have been synthesized by reactions of Cu(CH3COO)2·H2O with Na(m-OOCH4C6Fc) and three types of N-donor ligands, respectively. X-ray diffraction analysis reveals that 1 shows a dimeric structure with a Cu⋯Cu distance of 2.5872(16) Å. 2 and 3 exhibit a mononuclear structure. The adjacent mononuclear molecules are packed into a one-dimensional (1D) chain through the π–π interactions between the bpy rings in 2 or phen rings in 3. 4 displays a 1D zigzag chain structure. In 1, the m-OOCH4C6Fc anion adopts the bidentate-bridging coordination mode, whereas it adopts the bidentate-chelating coordination mode in 2–4. Magnetic study indicates that an antiferromagnetic interaction between the CuII ions exists in 1.

CdS formation upon decomposition of Cd(n-BuOCS2)2 in EtOH and DMF and the crystal structure of Cd(Ph3P)(n-BuOCS2)2 · Ph3P

The thermal decomposition of the chelate Cd(n-BuOCS2)2 (I) in EtOH and DMF, either in the absence or in the presence of Ph3P, yields finely disperse CdS particles. Mixed-ligand complex Cd(Ph3P)(n-BuOCS2)2 (II) has been synthesized. Cd(Ph3P)(n-BuOCS2)2 · Ph3P (III) single crystals have been grown. By X-ray crystallography, the crystal structure of III is built of [Cd(Ph3P)(n-BuOCS2)2] mononuclear complex molecules and uncoordinated Ph3P molecules, which reside inside channels formed by complex II molecules. The coordination polyhedron around a Cd atom is a tetragonal pyramid where the base is formed by the four S atoms of the two bidentate chelating ligands n-BuOCS2− and the P atom of the Ph3P ligand is at the axial vertex. In the structure of III, there are supramolecular assemblies of two complex II molecules.