Mononuclear and binuclear lanthanide(III) complexes: syntheses,structural, photophysical and thermal properties

Six new Ln(III) complexes viz., [Gd(tptz)(SCN)₃(CH₃OH)₂OH₂]·CH₃OH (1), [Eu(tptz)(SCN)₃(CH₃OH)₂OH₂]·CH₃OH (2), [Tb(tptz)(SCN)₃(OH₂)₃]₄ (3), [Gd(tptz)(OBz)₂(μ-OBz)OH₂]₂·2H₂O (4), [OH₂(OBz)₂(tptz)Eu₁(μ-OBz)₂Eu₂(tptz)(OBz)₂OH₂]·CH₃OH·7H₂O (5), and {[Tb₁(tptz)(OBz)₂(μ-OBz)]₂·[Tb₂(tptz)(OBz)₃CH₃OH]₂}·2CH₃OH·4H₂O (6) (Ln = Gd, Eu, Tb; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine; BzONa = sodium benzoate), have been synthesized and characterized by physicochemical methods including single-crystal X-ray crystallography. The X-ray studies demonstrate that 1–3 are mononuclear, whereas 4–6 are binuclear. The photophysical properties of 1–6 have been studied with ultraviolet absorption and emission spectral studies. Their thermal properties have been studied by thermogravimetric (TG) and derivative thermogravimetric analysis (DTG), demonstrating that the final product after decomposition was Ln₂O₃ for all these complexes.     

Crystallisation Solvent Influence on the Crystal Structures of MnII and NiII Complexes with 2,6‐bis(1‐salicyloylhydrazonoethyl)pyridine,H4daps

Neutral manganese and nickel complexes of the empirical formulae Mn(H₂daps)(H₂O)_0.5 and Ni(H₂daps) · (H₂O)_1.5(CH₃CN) have been prepared by electrochemical syntheses. The structures of the complexes formed from solvents with different donor ability were investigated. Recrystallisation of Mn(H₂daps)(H₂O)_0.5 from pyridine and ethanol yields [Mn(H₂daps)(py)₂] 1 and [Mn(H₂daps)(C₂H₅OH) · (H₂O)] 2 . Slow evaporation of dichloromethane and methanol solutions of Ni(H₂daps)(H₂O)_1.5(CH₃CN) allows the isolation of single crystals of [Ni₂(H₂daps)₂] · CH₂Cl₂ 4 and [Ni₂(H₂daps)₂(CH₃OH)₂] · 3 CH₃OH · H₂O 5 , suitable for X‐ray diffraction studies. Recrystallisation of 4 from pyridine yields [Ni₂(H₂daps)₂(py)₂] · CH₂Cl₂ 6 , previously characterised by us. This study shows the versatility of the H₄daps ligand and the influence that the crystallisation solvent can have on the crystal structure of these complexes.     

Coordination compounds of neodymium(III) with acyldihydrazones of saturated dicarboxylic acids and 3-methyl-1-phenyl-4-formylpyrazol-5-one

Coordination compounds of neodymium(III) with acylhydrazones of saturated dicarboxylic acids and 3-methyl-1-phenyl-4-formylpyrazol-5-one are synthesized and studied. The structure of complex [Nd₂(H₂L²)₃] · Me₂SO · CH₃OH · 6H₂O is determined from the X-ray diffraction data for the isostructural lanthanum complex. The complex is binuclear and contains nine-vertex coordination polyhedra bound by three hydrocarbon spacers. Solid samples of the studied neodymium complexes exhibit luminescence in the near-infrared spectral range (λ = 874, 904, and 1059 nm) characteristic of this ion.     

Facile and Optimized Syntheses and Structures of Crystalline Molybdenum Blue Compounds Including one with an Interesting High Degree of Defects: Na26[Mo142O432(H2O)58H14] · ca. 300 H2O and Na16[(MoO3)176(H2O)63(CH3OH)17H16] · ca. 600 H2O · ca. 6 CH3OH

The syntheses and structures of the two mixedvalence crystalline molybdenum blue compounds Na₂₆[Mo₁₄₂O₄₃₂(H₂O)₅₈H₁₄] · ca. 300 H₂O ( 1 ) (containing the maximal number of well defined defects which influence the overall structure and the reactivity of the anionic cluster) and Na₁₆[(MoO₃)₁₇₆(H₂O)₆₃(CH₃OH)₁₇H₁₆] · ca. 600 H₂O · ca. 6 CH₃OH ( 2 ) (obtained in an optimized high-yield synthesis) are reported with reference to the critical conditions required for the isolation of corresponding crystalline materials.     

Syntheses,crystal structures,and fluorescent properties of two Cd(II) complexes based on 2,2′-(ethane-1,2-diyl)bis(1H-imidazole-4,5-dicarboxylic acid)

Two new complexes, [Cd₂(H₄ebidc)₂(CH₃OH)₄]?·?2CH₃OH (1) and {[Cd(Cl)(I)(H₆ebidc)_1/2]?·?1/2bbe?·?H₂O} _n (2) (H₆ebidc?=?2,2′-(ethane-1,2-diyl)bis(1H-imidazole-4,5-dicarboxylic acid), bbe?=?1,2-bis(2-benzimidazolyl)ethane), are obtained through self-assembly of H₆ebidc with Cd(II). Single-crystal X-ray diffraction shows that 1 has a binuclear structure and each tridentate chelating ligand coordinates to two Cd(II) ions with µ₂-O. Complex 2 displays a 1-D chain structure and each tetradentate ligand bridges two Cd(II) ions in chelating fashion. Fluorescent properties have also been determined.     

Porous Metal‐organic Framework based on Strip‐shaped Manganese(II) Chains: Synthesis,Structure, and Magnetic Properties

The Mn^II‐based porous metal‐organic framework, [Mn₃(btca)₂(HCOO)(μ₃‐OH)(H₂O)₂] · 2DMF ( 1 ) (H₂btca = benzotriazole‐5‐carboxylate acid), was prepared by the solvothermal reaction of Mn(CH₃COO)₂ · 4H₂O and H₂btca, which was characterized by infrared spectroscopy, thermogravimetric analyses, and X‐ray crystallographic study. 1 exhibits 3D framework with 1D rectangle channels constructed by the strip‐shaped chains containing [Mn₅(μ₃‐OH)₂(btca)₄]^– pentaclusters subunits. Furthermore, the magnetic measures show that 1 exhibits weak ferromagnetic behavior at low temperature.     

Syntheses,Structures and Characterization of Four Metal‐Organic Frameworks constructed by 2,2′,6,6′‐Tetramethoxy‐4,4′‐biphenyldicarboxylic Acid

Four metal‐organic frameworks (MOFs), {[Mn_3.5L(OH)(HCOO)₄(DMF)] · H₂O} ( 1 ), {[In_2.5L₂O(OH)_1.5(H₂O)₂] · DMF · CH₃CN · 2H₂O} ( 2 ), {[Pb₄L₃O(DMA)] · CH₃CN} ( 3 ), and {[LaL(NO₃)(DMF)₂] · 2H₂O} ( 4 ) were synthesized by utilizing the ligand 2,2′,6,6′‐tetramethoxy‐4,4′‐biphenyldicarboxylic acid (H₂L) via solvothermal methods. All MOFs were characterized by single‐crystal X‐ray diffraction, powder X‐ray diffraction, thermogravimetric analysis, and infrared spectroscopy. In 1 , the Mn²⁺ ions are interconnected by formic groups in situ produced via DMF decomposition to form a rare 2D macrocyclic plane, which is further linked by L^2– to construct the final 3D network. In 2 , 1D zip‐like infinite chain is formed and then interconnected to build the 3D framework. In 3 , a [Pb₆(μ₄‐O)₂(O₂C)₁₀(DMA)₂] cluster with a centrosymmetric [Pb₆(μ₄‐O)₂]⁸⁺ octahedral core is formed in the 3D structure. In 4 , the La³⁺ ions are connected with each other through carboxylate groups of L^2– to generate 1D zigzag chain, which is further linked by L^2– to construct a 3D network with sra topology. Solid photoluminescence properties of 3 and 4 were also investigated.     

Acid-Base Interactions of Pyrazine,Ethyl Acetate,Di-alcohols,and Lysine with the cyclic Alumosiloxane (Ph2SiO)8[Al(O)OH]4 in View of Mimicking Al2O3(H2O) Surface Reactions

The etherate of (Ph₂SiO)₈[Al(O)OH]₄ can be transformed into the pyrazine adduct (Ph₂SiO)₈[Al(O)OH]₄ · 3N(C₂H₂)₂N ( 1 ), the ethyl acetate adduct (Ph₂SiO)₈[Al(O)OH]₄ · 3H₃C-C(O)OC₂H₅ ( 2 ), the 1,6-hexane diol adduct (Ph₂SiO)₈[Al(O)OH]₄ · 2HO–CH₂(CH₂)₄CH₂–OH ( 3 ) and the 1,4-cyclohexane diol adduct (Ph₂SiO)₈[Al(O)OH]₄ · 4HO–CH(CH₂CH₂)₂CH–OH ( 4 ). In all compounds the OH groups of the starting material bind to the bases through O–H ··· N ( 1 ) or O–H ··· O hydrogen bonds ( 2 , 3 , 4 ) as found from single-crystal X-ray diffraction analyses. Whereas in 1 only three of the central OH groups bind to the pyrazines, in 2 two of them bind to the same carbonyl oxygen atom of the ethyl acetate resulting in an unprecedented O–H ··· O ··· H–O double hydrogen bridge. The hexane diol adduct 3 in the crystal forms a one-dimensional coordination polymer with an intramolecularly to two OH groups grafted hexane diol loop, while the second hexane diol is connecting intermolecularly. In the cyclohexane diol adduct 4 all OH groups of the central Al₄(OH)₄ ring bind to different diols, leaving one alcohol group per diol uncoordinated. These “free” OH groups form an (O-H ··· )₄ assembly creating a three-dimensional overall structure. When reacting with (Ph₂SiO)₈[Al(O)OH]₄ lysine loses water, turns into the cyclic 3-amino-2-azepanone, and transforms through chelation of one of the aluminum atoms the starting material into a new polycycle. The isolated compound has the composition (Ph₂SiO)₁₂[Al(O)OH]₄[Al₂O₃]₂ · 4 C₆H₁₂N₂O · 6(CH₂)₄O ( 5 ).     

Syntheses,structures, and optical properties of two cadmium complexes with chelidamic acid

[Cd₂(C₇H₃NO₅)₂ · 4(H₂O)] _n · 3nH₂O · 0.5n(CH₃OH) (1) and [Cd₃(C₇H₂NO₅)₂ · 10(H₂O)] · 2H₂O ·0.5CH₃OH (2) were synthesized and characterized by X-ray single-crystal diffraction. The crystal structure of 1 reveals that both Cds are seven-coordinate with pentagonal bipyramid geometries. Coordination polyhedra are interlinked into a 1-D chain, further linked by hydrogen bonds into a 3-D network. Complex 2 is a discrete structure, then independent [Cd₃(C₇H₂NO₅)₂ · 10(H₂O)] are linked by hydrogen bonds into a 3-D network. The optical properties of 1 and 2 were investigated with fluorescent spectra; both exhibit strong green luminescence probably originating from π–π* transition of the ligand.     

Isomorphous rare‐earth tris[bis(2,6‐diisopropylphenyl) phosphate] complexes and their catalytic properties in 1,3‐diene polymerization and in the inhibited oxidation of polydimethylsiloxane

Crystals of mononuclear tris[bis(2,6‐diisopropylphenyl) phosphato‐κO]pentakis(methanol‐κO)lanthanide methanol monosolvates of lanthanum, [La(C₂₄H₃₄O₄P)₃(CH₃OH)₅]·CH₃OH, ( 1 ), cerium, [Ce(C₂₄H₃₄O₄P)₃(CH₃OH)₅]·CH₃OH, ( 2 ), and neodymium, [Nd(C₂₄H₃₄O₄P)₃(CH₃OH)₅]·CH₃OH, ( 3 ), have been obtained by reactions between LnCl₃(H₂O)_n (n = 6 or 7) and lithium bis(2,6‐diisopropylphenyl) phosphate in a 1:3 molar ratio in methanol media. Compounds ( 1 )–( 3 ) crystallize in the monoclinic P2₁/c space group and have isomorphous crystal structures. All three bis(2,6‐diisopropylphenyl) phosphate ligands display a κO‐monodentate coordination mode. The coordination number of the metal atom is 8. Each [Ln{O₂P(O‐2,6‐ⁱPr₂C₆H₃)₂}₃(CH₃OH)₅] molecular unit exhibits four intramolecular O—H…O hydrogen bonds, forming six‐membered rings. The unit forms two intermolecular O—H…O hydrogen bonds with one noncoordinating methanol molecule. All six hydroxy H atoms are involved in hydrogen bonding within the [Ln{O₂P(O‐2,6‐ⁱPr₂C₆H₃)₂}₃(CH₃OH)₅]·CH₃OH unit. This, along with the high steric hindrance induced by the three bulky diaryl phosphate ligands, prevents the formation of a hydrogen‐bond network. Complexes ( 1 )–( 3 ) exhibit disorder of two of the isopropyl groups of the phosphate ligands. The cerium compound ( 2 ) demonstrates an essential catalytic inhibition in the thermal decomposition of polydimethylsiloxane in air at 573 K. Catalytic systems based on the neodymium complex tris[bis(2,6‐diisopropylphenyl) phosphato‐κO]neodymium, ( 3′ ), which was obtained as a dry powder of ( 3 ) upon removal of methanol, display a high catalytic activity in isoprene and butadiene polymerization.     

Greener solid state synthesis of a ternary lanthanum complex at room temperature

Wet chemical synthesis of rare-earth complexes often requires large amounts of solvents to dissolve reactants, and the use of base to neutralize acidic solution. We have explored a green alternative route that involves solid-state synthesis of ternary lanthanum complex at room temperature by using lanthanum chloride hydrate (LaCl_3?·?6H₂O), sodium p-hydroxybenzoate (PBA), and 8-hydroxyquinoline (8-hq). The structure and composition of the ternary lanthanum complex were confirmed by microanalysis, Fourier transform infrared (FT-IR), UV-Vis, X-ray diffraction (XRD), electron diffraction, and thermogravimetric analysis. UV-Vis and FT-IR spectra confirms coordination of lanthanum ion with two ligands and XRD results show that signals of the product are not from the three reactants, and are believed to originate from the ternary lanthanum complex prepared by solid-state reaction. Effects of reaction conditions such as molar ratios and synthetic method on the formation of ternary lanthanum complex were also investigated. The structure and composition of the ternary lanthanum complex are independent of molar ratios of reactants. Compared to the ternary lanthanum complex prepared via solution-phase synthesis, although the ternary lanthanum complex prepared by solid-state reactions has the same composition and structure, the synthesis is scalable and greener.     

Two Chain Like B-Type-Anderson-Based Hybrids Synthesized in Choline Chloride/Urea Eutectic Mixture

Two new chain like B-Anderson type polyoxomolybdates based hybrids {Na[(CH₃)₃N(CH₂)₂OH]₂}[Al(OH)₆Mo₆O₁₈]·2(NH₂CONH₂)·6H₂O (1) and {Na[(CH₃)₃N(CH₂)₂OH]₂}[Cr(OH)₆Mo₆O₁₈]·2(NH₂CONH₂)·6H₂O (2) were synthesized in choline chloride/urea eutectic mixture and characterized by element analysis, IR, UV–vis, TG, single-crystal X-ray analysis, and power X-ray diffraction. Through the linkage [Na(H₂O)₂(NH₂CONH₂)₂]⁺, the [X(OH)₆Mo₆O₁₈]³⁻ (X = Al, Cr) units are arranged into a chain. Considering hydrogen bonding interactions between the chains, compound 1 and 2 are all well-arranged into 3-D supermolecular assembly. The structure is first obtained in the choline chloride/urea eutectic mixture.     

A novel single‐electron sodium bond system of H3C···Na?Y (YH,OH, F,CCH, CN,and NC)

A novel single‐electron sodium bond system of H₃C···Na? H (I), H₃C···Na? OH(II), H₃C···Na? F(III), H₃C···Na‐CCH(IV), H₃C···Na? CN (V) and H₃C···Na? NC (VI) complexes has been studied by using MP2/6‐311++G** and MP2/aug‐cc‐pVTZ methods for the first time. We demonstrated that the single‐electron sodium bond H₃C···Na? Y formed between H₃C and Na? Y (Y?H, OH, F, CCH, CN, and NC) could induce the Na? Y increased and stretching frequencies of I–IV and VI are red‐shifted, including the Na? N bond in complex V is blue‐shifted abnormally. The interaction energies are calculated at two levels of theory [MP2, CCSD(T)] with different basis. The results shows that the strength of binding bond in group 2 (IV–VI) with π electrons are stronger than that of group 1 (I–III) without π electrons. For all complexes, the main orbital interactions between moieties H₃C and Na? Y are LP₁(C)→LP*₁(Na). By comparisons with some related systems, it is concluded that the strength of single‐electron bond is increased in the order: hydrogen bond < bromine bond < sodium bond < lithium bond. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

A trinuclear Cu(II) precursor for solvatochromically distinguishing CH3OH from C2H5OH

Abstract

In order to develop an easy and rapid identification method for distinguishing CH₃OH from C₂H₅OH, a new carbonate-based trinuclear Cu(II) precursor, [Cu₃(bpy)₆(μ₃-CO₃)(CH₃OH)](BF₄)₄·(CH₃OH)₂·(H₂O)₂ (1), has been isolated. We report here the synthesis, crystal structure, and characterizations by various spectroscopic (IR, UV–Vis, powder XRD) techniques, as well as the solvatochromic behavior of this coordination compound. Its X-ray crystal structure reveals that the main structure of 1 consists of three [(bpy)₂Cu]²⁺ centers, which are bridged by carbonate via a μ₃-η¹,η¹,η¹ fashion. Strong O–H?O hydrogen bonding between the carbonate and solvent molecules has been observed for the first time in similar structures. Its ground powder exhibits solvatochromic behavior that selectively distinguishes CH₃OH from C₂H₅OH.     

Ligand condensation of P(CH2OH)3: Synthesis and structure of [Ni3S2{(CH2OH)2PCH2OP(CH2OH)2}3][Mo6Cl14] · 0.8H2O

Reaction of NiCl₂ · 6H₂O and P(CH₂OH)₃ (THP) with H₂S and (H₇O₃)₂[Mo₆Cl₁₄] · 3H₂O in ethanol produces new trinuclear nickel sulphide complex [Ni₃(μ₃-S)₂{(HOCH₂)₂PCH₂OP(CH₂OH)₂}₃][Mo₆Cl₁₄] · 0.8H₂O (I) with new bidentate phosphine-phosphinite ligand resulted from THP condensation. It was characterized by X-ray structure analysis.     

Preparation of non-valence compounds of zinc(II) with 1,2- and 1,4-benzenedicarboxylic acids via self-assembly

Nanostructured non-valence compounds based on coordination compounds of zinc(II) with phthalic and terephthalic acids have been prepared. The purity and composition of prepared compounds have been elucidated from X-ray diffraction analysis, IR spectroscopy, elemental analysis, and thermogravimetry studies; thermal decomposition of the non-valence compounds has been studied as well. The prepared self-assembled compounds are co-precipitated with one water molecule and 1.5 acetic acid molecules per unit of the dicarboxylic acid: [Zn₄(OH)₆·o-C₆H₄(COO)₂]·H₂O·1.5CH₃COOH and [Zn₄(OH)₆·p-C₆H₄(COO)₂]·H₂O· 1.5CH₃COOH.     

One Dinuclear Copper(II) Polymer Based on <Emphasis Type="Italic">N</Emphasis>-(Pyridine-3-Sulfonyl Amino)-Acetate: Synthesis,Structure, and Magnetic Analysis

The reaction of CuCl₂ · 2H₂O with N-(pyridine-3-sulfonyl amino)-acetate (H₂L) in ethanol, water and 4,4′-Bipy under solvothermal conditions leads to the formation of a dinuclear copper polymer {[Cu₂(L)₂(4,4′-Bipy)(H₂O)₂] · H₂O · CH₃OH} _n (I). The polymer was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and X-ray single-crystal diffraction (CIF file CCDC no. 1543747). The results showed that polymer belongs to the triclinic system, \(P\bar 1\) space group. TG curve shows that polymer I first removes water molecules, and then the ligand split for polymers I, and the remained residue is CuO. The magnetic measurement reveals the N-(pyridine-3-sulfonyl amino)-acetate as bridge ligand can mediate the antiferromagnetic coupling interaction between magnetic centers.     

Mercury complexes with 1,2,6,7-tetracyano-3,5-dihydro-3,5-diimino-pyrrolizinide

The anion 2-(5-amino-3,4-dicyano-2H-pyrrol-2-ylidene)-1,1,2-tricyanoethanide (L′, C₁₁H₂N₇⁻), after isomerization to 1,2,6,7-tetracyano-3,5-dihydro-3,5-diimino-pyrrolizinide (L), forms different metal-complexes with mercury depending on the experimental conditions. Pure compounds were isolated from the reactions HL+CH₃HgAc in CH₃CN and NaL′+HgAc₂ in AcH/H₂O. They are CH₃HgL and HgL₂. From their optical spectra, compared to those of phthalocyaninato- or other well-known pyrrolizinato-complexes, the coordination geometry of Hg(II) in these species is supposed to be trigonal planar and trigonal monopyramidal, respectively. CH₃HgL was characterized also by ¹H NMR: (CD₃CN, δ, ppm) 0.886 (CH₃), 8.733 (NH). From the reactions in water between NaL′ and HgCl₂ or HgClO₄ complex mixtures of polynuclear complexes were isolated of composition: 0.826 [Hg₂ClL₂(OH)]·0.174 [Hg₄L₃(OH)₅]·2.06 H₂O (A) or 0.588 [Hg₂L₂]·0.412 [Hg₂L(OH)₃]·3.53 H₂O (B), respectively. The formulae A and B were based on thermogravimetric and elemental analysis data. Indirect evidences, based on XPS data, for the existence of the pyrrolizinato–Hg(I) complex are also given.     

Synthesis,Structures, and Properties of Four Novel Coordination Compounds based on a Flexible Tetrakis(imidazol‐1‐ylmethyl)methane Ligand

Four coordination polymers, namely, [Zn₂(TIYM)(2,6‐PYDC)₂]_n · n(CH₃OH) · 3n(H₂O) ( 1 ), [Cu(TIYM)(2,6‐PYDC)]_n · 3n(H₂O) ( 2 ), [Co(TIYM)(2,6‐PYDC)]_n · n(CH₃OH) · 3n(H₂O) ( 3 ), and [Cd₂(TIYM)(2,6‐PYDC)₂(H₂O)]_n · n(H₂O) ( 4 ) with the flexible N‐containing ligand [tetrakis(imidazol‐1‐ylmethyl)methane (TIYM)] and the N‐containing dicarboxylic acid [2,6‐pyridinedicarboxylic acid (2,6‐PYDC)] were prepared. Compounds 1 – 4 show various structures because of different N–C_center–N angles (θ) of TIYM ligands and changing coordination modes of 2,6‐PYDC. Compounds 1 , 2 , and 3 display a similar 1D ladder‐like chain, whereas 4 gives a 1D quad‐core lifting platform shaped belt. The structural diversities in 1 – 4 suggest that the multiple coordination modes or the different freely twist angles of ligands and the presence of different metal atoms play important roles in the resulting structures of the coordination polymers. Furthermore, the solid‐state luminescence properties of 1 and 4 , and the magnetic properties of 3 were investigated.     

Synthesis and Properties of Complexes with Unusual {MnIII4} and {MnII4} Cages

Two types of manganese complexes with [Mn₄] cores featuring the unusual distorted cube topology are presented, the first of which comprises new modifications of the reported complex [Mn^III₄(sao)₄(saoH)₄]·3CHCl₃: [Mn₄(sao)₄(saoH)₄]·1.32(C₄H₁₀O)·0.43(CH₄O) ( 1a ) and [Mn(sao)₄(saoH)₄]·0.5(CH₄O)·0.5(C₂H₃N) ( 1b ) sao = salicylaldoxime. The second, 0.55[Mn₄Cl₄(C₁₂H₉N₂O)₄(CH₃OH)₂(H₂O)₂]·0.45[Mn₄Cl₄(C₁₂H₉N₂O)₄(CH₃OH)₄] ( 2 ), is the first reported case of a {Mn^II₄} core of this topology besides known {Mn^III₄} compounds. Differences between the {Mn^II₄} and {Mn^III₄} situation are discussed, and so far overlooked differences in magnetic properties between different {Mn^III₄} compounds are pointed out.