Dipicolinate complexes of main group metals with hydrazinium cation

Some new coordination complexes of hydrazinium main group metal dipicolinate hydrates of formulae (N₂H₅)₂M(dip)₂.nH₂O (where, M = Ca,Sr,BaorPb andn = 0, 2, 4 and 3 respectively and dip = dipicolinate), N₂H₅Bi(dip)₂.3H₂O and (N₂H₅)₃Bi(dip)₃.4H₂O have been prepared and characterized by physico-chemical techniques. The infrared spectra of the complexes reveal the presence of tridentate dipicolinate dianions and non-coordinating hydrazinium cations. Conductance measurements show that the mono, di and trihydrazinium complexes behave as 1:1, 2:1 and 3 :1 electrolytes respectively, in aqueous solution. Thermal decomposition studies show that these compounds lose water followed by endothermic decomposition of hydrazine to give respective metal hydrogendipicolinate intermediates, which further decompose exothermically to the final product of either metal carbonates (Ca, Sr, Ba and Pb) or metal oxycarbonates (Bi). The coordination numbers around the metal ions differ from compound to compound. The various coordination numbers exhibited by these metals are six (Ca), seven (Ba), eight (Sr) and nine (Pb and Bi). In all the complexes the above coordination number is attained by tridentate dipicolinate dianions and water molecules. The X-ray diffraction patterns of these compounds differ from one another suggesting that they are not isomorphous.     

Hydrotris(1,2,4‐triazolyl)borato Complexes with the Main Group Elements Ca,Sr, and Pb – Unexpectedly Bent ML2 Structures and a Stereochemically Inactive Lone Pair at Lead(II)

The coordination of the modified poly(azolyl)borato ligand hydrotris(1,2,4‐triazolyl)borato (L) with main group metals leads to complexes with coordination numbers of eight and the formula [CaL₂(H₂O)₂], [SrL₂(H₂O)₂], and [PbL₂(H₂O)₂]. The two L ligands coordinate in a “bent” arrangement to allow for the coordination of the two aqua ligands. This is in sharp contrast to six‐coordinated, pseudo‐octahedral CaTp₂ and PbTp₂ complexes [Tp = hydrotris(pyrazolyl)borato]. The calcium, strontium, and lead complexes are isostructural. No stereochemical lone pair activity is evident in [PbL₂(H₂O)₂]. Two additional water molecules of crystallization complete the crystal structure of [CaL₂(H₂O)₂] · 2 H₂O and [PbL₂(H₂O)₂] · 2 H₂O. In the synthesis of [PbL₂(H₂O)₂] an intermediate of the form [Pb(μ₃‐L)(NO₃)H₂O] could isolated and structurally characterized. There, the lead(II) center is seven coordinated with a presumably stereochemically active lone pair. Long M–L bonds argue for a more ionic bonding to the modified tris(triazolyl)borato ligand when compared to analogous M–Tp complexes.     

Crystal structures of two Ca(II) complexes with imidazole-4,5-dicarboxylate and water ligands

The structure of compound I: poly-diaqua(μ-imidazole-4,5-dicarboxylato-N,O; -O′; -O′′, -O′′′) calcium(II) monohydrate [Ca(C₅H₂N₂O₄)(H₂O)₂·H₂O] is built of molecular sheets in which imidazole-4,5-dicarboxylate ligands bridge the metal ions using both carboxylate groups, each bidentate. Ca(II) is coordinated by six oxygen atoms and one hetero-ring nitrogen atom distributed at the apices of a capped tetragonal bipyramid. The basal plane of the pyramid is formed by two carboxylate oxygen atoms [d(Ca–O2?=?2.374(1)?Å, d(Ca–O4)?=?2.412(1)?Å] and two water oxygen atoms [d(Ca–O5)?=?2.384(1)?Å, d(Ca–O6)?=?2.455(1)?Å], the capped position is occupied by the carboxylate oxygen atom O3 [d(Ca–O3)?=?2.325(1)?Å], the hetero-ring nitrogen atom [d(Ca–N2)?=?2.523(1)?Å] and the carboxylate oxygen atom O4 [d(Ca–O2)?= 2.412(1)?Å] form the apices of the prism. The solvation water molecule plays a significant role in a framework of hydrogen bonds responsible for the stability of the crystal. The structure of compound II: trans-tetraquadi(H-imidazole-4,5-dicarboxylato-N,O) calcium(II) monohydrate, [Ca(C₅H₃N₂O₄)₂(H₂O)₄·H₂O] consists of monomers in which the Ca(II) ion is located on a centre of symmetry. The coordination around the Ca(II) is a strongly deformed pentagonal bipyramidal with the imidazole-4,5-dicarboxylate (4,5-IDA) ligands in the trans arrangement forming a dihedral angle of 68.3°. An imidazole-ring nitrogen atom [d(Ca–N)?=?2.632(2)?Å] and one carboxylate O atom [d(Ca–O)?=?2.531(2)?Å] from each ligand coordinate to the metal ion. The coordination is completed by four water oxygen atoms [d(Ca–O)?=?2.393(2)?Å] and [d(Ca–O)?=?2.367(2)?Å]. The coordinated water molecules act as hydrogen bond donors and acceptors to the unbonded carboxylate oxygen atoms in adjacent monomers giving rise to a three-dimensional molecular network.     

Structural features of the crystalline iodide complexes of some rare-earth elements with carbamide and acetamide

New acetamide and carbamide complexes LnI₃ · 4Ur · 4H₂O (Ln = La, Eu, Dy, Ho, Y; Ur is carbamide) and LnI₃ · 4AA · 4H₂O (Ln = Nd, Eu, Dy, Ho, Y; AA is acetamide) are synthesized. The complexes are characterized by the data of chemical analysis, IR spectroscopy, and X-ray diffraction analysis. The ligands (water, carbamide, and acetamide molecules) are coordinated by the rare-earth element atoms through the oxygen atom, and the coordination polyhedron is a distorted square antiprism. The iodide ions are not coordinated and are located in the external sphere. The structural characteristics of the complexes are compared in the series [Ln(L)₄(H₂O)₄]I₃ (Ln = La, Nd, Eu, Gd, Dy, Ho, Er; L = AA, Ur).     

Synthesis and structure of aqua-2′,?-(2,6-pyridindiyldiethylidene) dioxamohydrazide-copper(II) hydrate

In a template synthesis from copper(II) acetate, 2,6-diacetylpyridine, and semioxamazide (NH₂CO CONHNH₂), two copper(II) complexes, [Cu(dapsox)(H₂O)]·H₂O and [Cu(Hdapsox)](H₂O)]ClO₄, (where H₂dapsox = 2′,2?-(2,6-pyridindiyldiethylidene)dioxamohydrazide) were obtained and characterized. The structure of the former complex was determined by a single-crystal X-ray analysis. Cu^II is located in a square pyramidal environment. The polydentate ligand, dapsox²⁻ is coordinated in dianionic form, as an unsymmetrical quadridentate planar system forming one-membered and two-five-membered metal-chelate rings. The fifth coordination site is occupied by a water molecule.     

基于3,4-吡唑二甲酸为配体的二个过渡金属配合物的合成、结构及荧光性质

以3,4-吡唑二甲酸（H₃pdc）为配体分别与氯化铜、氯化镍反应,得到了2个过渡金属配合物：[M（H₂pdc）₂（H₂O）₂]·2H₂O（M=Cu（1）和Ni（2））,用元素分析、红外光谱、X-单晶衍射结构分析、热重分析和荧光分析对其进行了表征。晶体结构分析表明配合物1和2均为单核结构,金属离子与来自2个H₂pdc^-中的2个N原子和2个羧基O原子,以及2个水分子中的2个O原子配位,形成六配位的八面体构型。配合物1和2中的独立结构单元[M（H₂pdc）₂（H₂O）₂]2H₂O通过3种分子间氢键（O-H…O,N-H…O和C-H…O）形成三维3D空间结构;此外我们还研究了配合物1和2的热稳定性和荧光性质。     

Thermogravimetric and spectroscopic studies on La(III) and Ce(III) complexes with some thio-schiff bases

Solid complexes of five derivatives of thio-Schiff bases with La(III) and Ce(III) ions were prepared and characterized by elemental and thermogravimetric analyses. The suggested general formula of the solid complexes is [ML₂(H₂O)X]·2H₂O, whereM=trivalent lanthanide ion,L=Schiff base andX=Cl^? or ClO ₄ ^? . Information about the water of hydration, the coordinated water molecules, the coordination chemistry and the thermal stability of these complexes was obtained and is discussed. Additionally, a general scheme of thermal decomposition of the lanthanide-Schiff base complexes is proposed.     

Metal α, ω dicarboxylate complexes. 4. Effect of N-donor substitutions on the polymeric network in cobalt(II) hexanedioate complexes: synthesis and single crystal X-ray investigations

Three cobalt (II)hexanedioate complexes [Co(H₂O)₄(H₂L)]n 1 (H₂L=hexanedioic acid), Co(imidazole)₄ (H₂L)]n 2 and [Co(pyridine)₂ (H₂O)₄][H₂L] 3 are synthesized and structurally characterized to study the effect of N-donor substituents coordinated to the metal center on the polymeric network. Complex 1 is an extended linear polymer; Co(H₂O)₄ units are linked by the monodendate carboxylate from either end of the extended deprotonated hexanedioic acid. There are intra- and interchain H-bonding interactions between the coordinated water molecules and the end carboxylate O atoms, the uncoordinated O atom creates two dimensional hydrogen bonding pattern. Complex 2 also is a linear polymer; Co(imidazole)₄ units are linked by monodentate dibasic acid at the either end but with S shaped conformation of the hexanedioic acid, not as fully extended as in 1. The effect of bulkier N-donor substitution is seen in the distortion of the octahedral coordination polyhedron of Co(II). The noncordinated carboxylate oxygen makes one intra and one interchain H-bonding interaction with the imidazole N–H group making a two-dimensional H-bonded network as in 1. In 3 with the two strong N-donor pyridines coordinated to the metal center, the hexanedioate is out of the coordination sphere and acts as a counter ion. The Co(pyridine)₂(H₂O)₄ units are linked by H-bonding in both the dimensions by extensively folded adipate dianion forming a sheet structure parallel to ab plane. According to our knowledge this is the first example showing a strong H-bonding network in which a tetraaquaCo(II) center forms an eight-membered ring with bidendate H-bonding interactions. None of the coordination polymeric structures form any channels in their molecular packing, even to include a small entity as a water molecule.     

Complexes of lanthanum,gadolinium, and erbium iodides with acetamide: Synthesis and structure

New acetamide complexes of lanthanum, gadolinium, and erbium iodides of the composition LnI₃ · 4AA · 4H₂ O (Ln = La, Gd, Er; AA = CH₃CONH₂) are synthesized and studied. The synthesized complexes are characterized by the data of chemical analysis and IR spectroscopy and are studied by X-ray diffraction analysis. The coordination of the ligands (water and acetamide molecules) by the lanthanum, gadolinium, or erbium atom occurs through the oxygen atoms. The coordination polyhedron of the Ln atom is a distorted square antiprism. The iodide ions are not coordinated and exist in the external sphere.     

Hydrothermal Synthesis and X‐Ray Structural Characterization of Manganese,Nickel, and Cadmium Coordination Polymers Containing 2,3‐Pyridinedicarboxylate as Multidentate Ligands

Three divalent transiton‐metal complexes of 2,3‐pyridinedicarboxylate (2,3‐pda²), [Mn(2,3‐pda)‐(H₂O)3]_∞ ( 7 ), [Ni(2,3‐pda)(H₂O)3]_∞ ( 8 ), and [Cd2(2,3‐pda)₂(H₂O)]_∞ ( 9 ) have been hydrothermally synthesized and structurally characterized. X‐ray diffraction analyses reveal that compounds 7 and 8 are zigzag‐ and linear‐type one‐dimension (1D) coordination polymers, respectively, whereas compound 9 is a three‐dimension (3D) coordination polymer. A simple comparison of the coordination geometries with the available neutral analogues {M_x(2,3‐pda)_x(H₂O)_y}_∞ containing one or two divalent transition‐metal atoms and equal ligands in the presence or absence of coordinated water molecules is also presented.     

Organotin Complexes of Alizarin and Purpurin

Five novel organotin complexes with the anthraquinone dyes alizarin (1,2‐dihydroxyanthraquinone) and purpurin (1,2,4‐trihydroxyanthraquinone) were synthesized and characterized by elemental analyses, FTIR and NMR spectroscopy (¹H, ¹³C and ¹¹⁹Sn). The crystal and molecular structures of four complexes were determined by X‐ray diffraction on single crystals: [Bu₂Sn(aliz)(H₂O)]·C₂H₅OH ( A1 ·EtOH), [Bu₂Sn(aliz)(dmso)]₂ ( A3 ), [(Bu₂Sn)₃O(Hpurp)₂] ( P1 ) and [Bu₂Sn(Hpurp)(dmso)]₂ ( P2 ), where H₂aliz = alizarin and H₃purp = purpurin. The coordination mode of the ligands is identical to that found in their Al/Ca complexes, where they act as dianionic tridentate ligands forming five and six‐membered fused chelate rings. The coordination to the tin atoms occurs exclusively via the 1,2‐ phenolate oxygen and the adjacent quinoid oxygen atoms. The complexes A1 , A3 and P1 are dimers with hepta‐coordinated tin atoms in form of a slightly distorted pentagonal bipyramid. The trinuclear complex P2 contains two pentacoordinated and one heptacoordinated tin atoms.     

Poly[[diaqua(μ3‐3‐nitrophthalato)calcium(II)] monohydrate]

The title 3‐nitrophthalate–calcium coordination polymer, {[Ca(C₈H₃NO₆)(H₂O)₂]·H₂O}_n, crystallizes as a one‐dimensional framework. The Ca^II centre has a distorted pentagonal–bipyramidal geometry, being seven‐coordinated by five O atoms from three different 3‐nitrophthalate groups and by two water molecules, resulting in a one‐dimensional zigzag chain along the a‐axis direction by the interconnection of the four O atoms from the two carboxylate groups. There is a D3 water cluster composed of the coordinated and the solvent water molecules within such chains. Adjacent chains are aggregated into two‐dimensional layers via hydrogen bonds in the c‐axis direction. The whole three‐dimensional structure is further stabilized by weak O—H...O hydrogen bonds between the O atoms of the nitro group and the water molecules.     

基于3,4-吡唑二甲酸为配体的两个过渡金属配合物的合成、结构及荧光性质

以3,4-吡唑二甲酸(H3pdc)为配体分别与氯化铜、氯化镍反应,得到了2个过渡金属配合物:[M(H2pdc)2(H2O)2]·2H2O(M=Cu(1)和Ni(2)),用元素分析、红外光谱、X-单晶衍射结构分析、热重分析和荧光分析对其进行了表征。晶体结构分析表明配合物1和2均为单核结构,金属离子与来自2个H2pdc-中的2个N原子和2个羧基O原子,以及2个水分子中的2个O原子配位,形成六配位的八面体构型。配合物1和2中的独立结构单元[M(H2pdc)2(H2O)2]·2H2O通过3种分子间氢键(O-H…O,N-H…O和C-H…O)形成三维(3D)空间结构;此外我们还研究了配合物1和2的热稳定性和荧光性质。     

Energetic calcium(II) complexes of 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)1,2,4,5-tetrazine: synthesis,crystal structure,and thermal properties

We synthesized two calcium salts of 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz): [Ca₂(BTATz)₂(H₂O)₈·6H₂O] (1) and Ca(BTATz)(phen)(H₂O)₅·4H₂O (2). Complexes 1 and 2 were characterized by elemental analysis, Fourier transform infrared spectrometry, and single-crystal X-ray diffraction. Structural analysis revealed that Ca(II) was present in different coordination structures in the two complexes. Complex 1 exhibited a symmetric octahedral coordination that included three nitrogens and five water molecules. Complex 2 formed an asymmetric seven-coordinate structure with calcium connected to nitrogen in BTATz and to oxygens. The thermal behaviors of 1 and 2 were characterized via differential scanning calorimetry and thermogravimetry–differential thermal gravimetry. The peak thermal decomposition temperatures of 1 and 2 was 557.39 and 573.86 K, respectively. The kinetic equations of the main exothermic decomposition reaction were also derived. Moreover, the thermal safety of the complexes was evaluated by calculating some important thermodynamic parameters, such as self-accelerated decomposition temperature, thermal ignition temperature, and critical temperature of thermal explosion. Results indicated that both complexes exhibit good potential as a propellant component.     

Syntheses and Structures of two Cobalt Coordination Polymers with Iminodiacetate Ligands: [CoII2(ida)2(H2O)2]n and [Na2CoIII2(ida)4(H2O)4]n·2nH2O

Two cobalt coordination polymers [Co^II₂(ida)₂(H₂O)₂]_n ( 1 ) and [Na₂Co^III₂(ida)₄(H₂O)₄]_n·2nH₂O ( 2 ) (H₂ida = iminodiacetic acid) have been synthesized and characterized by single‐crystal X‐ray diffraction analysis. Compound 1 exhibits a two‐dimensional framework, in which two cobalt atoms exhibit different coordination environments: one is equatorially coordinated by two ida ligands, while another is coordinated by two water molecules and four ida ligands. It is most interesting that, in compound 2 , the ida ligands exhibit different coordination modes. The organic coordination anions [Co^III(ida)₂]^— are linked up by sodium ions to form a two‐dimensional layer.     

Group II B Metal Complexes with N-Benzoylglycine (Hippuric Acid) and their Amine Adducts

Zn(II), Cd(II) and Hg(II) complexes with N-benzoylglycine (Hippuric acid) (abbreviation HHippu) and their amine adducts are of the type M(Hippu)₂. H₂O, M(Hippu)₂, M(Hippu)₂. B (M = Zn, Cd and Hg, and B = piperazine, 1, 10-phenantroline; M = Zn and B = Pyridine; M = Hg and B = ethylenediamine), M(Hippu)₂? 2B (B = N-methylpiperazine, piperidine, morpholine and pyridine) and M(Hippu)₂?3B (M = Zn, Cd and B = ethylenediamine). The amine and amino-acid coordination are investigated with the infrared spectra. The monohydrate and anhydrous bis(hippurate)metal(II) have identical i.r. spectra, indicating that the water molecule is not coordinated to the metal ions. A monodentate coordination of the amino acid is found in the amine adducts of Zinc(II), while in those of Cadmium(II) and Mercury(II)a symmetrical or asymmetrical bidentate coordination through the (COO^?) group is suggested and a pseudooctahedral configuration proposed. Only in monohydrate, anhydrous and monopyridine bis(hippurate) Zinc(II) (with the lowering of the ν (NH) of the ? NH-group of the N-benzoylglycine) does this group appear to be involved in the metal coordination.     

Reactions of metal(II) ions with sugar α-amino acids: nickel(II) complexes containing an α-amino acid derived from galactose or mannose

Summary The reaction of Ni^II ions with 2-(benzylamino)-2-deoxy-d-glycero-l-gluco. heptonic acid (BnGa:C₁₄H₂₁NO₇) or 2-(benzylamino)-2-deoxy-d-glycero-d-talo heptonic acid (BnMa:C₁₄H₂₁NO₇) in water yields complexes of formulae [Ni(BnGa)₂(H₂O)₂] and [Ni(BnMa)₂]·2H₂O, respectively, which were characterized by elemental analysis, spectral techniques (u.v.-vis.-n.i.r. and i.r.), magnetic susceptibility measurements, thermal measurements (t.g. and d.s.c.) and X-ray powder diffraction. Both complexes are octahedral with two positions of the coordination sphere occupied by nitrogen atoms. Moreover, in [Ni(BnMa)₂]·2H₂O four oxygen atoms of bridging carboxylate groups are coordinated to the metal ion, while in [Ni(BnGa)₂(H₂O)₂] only an oxygen atom of each carboxylate group is bound to Ni^II. In this case, the coordination is completed via two water molecules.     

A square‐pyramidal copper(II) complex with strong intramolecular hydrogen bonds: diaqua(N,N′‐dimethylformamide‐κO)bis[2‐(diphenylphosphoryl)benzoato‐κO]copper(II)

In the title Cu^II complex, [Cu(C₁₉H₁₄O₃P)₂(C₃H₇NO)(H₂O)₂], the molecule is bisected by a twofold axis relating the two 2‐(diphenylphosphoryl)benzoate (ODPPB) ligands. The asymmetric unit consists of a Cu^II metal centre on the symmetry axis, an ODPPB ligand, one water ligand and one dimethylformamide (DMF) ligand (disordered around the twofold axis). The Cu^II ion has fivefold coordination provided by two carboxylate O atoms from two ODPPB ligands, two O atoms from two coordinated water molecules and another O atom from a (disordered) DMF molecule, giving a CuO₅ square‐pyramidal coordination geometry. The ODPPB ligand adopts a terminal monocoordinated mode with two free O atoms forming two strong intramolecular hydrogen bonds with the coordinated water molecules, which may play a key role in the stability of the molecular structure, as shown by the higher release temperature for the coordinated water molecules than for the coordinated DMF molecule. The optical absorption properties of powder samples of the title compound have also been studied.     

Synthesis,characterization, and antibacterial activities of two new copper(II) glycinate complexes incorporating 2-(4′-thiazolyl)benzimidazole/2-(2-pyridyl)benzimidazole

Two new complexes, [Cu(TBZ)(Gly)(H₂O)]Cl (1) and [Cu(HPB)(Gly)Cl]?·?2H₂O (2) (TBZ?=?2-(4′-thiazolyl)benzimidazole, HPB?=?2-(2-pyridyl)benzimidazole, and Gly?=?glycinate), have been synthesized and characterized by elemental analysis, molar conductivity, UV-Vis, and IR methods. The complexes, structurally characterized by single-crystal X-ray crystallography, show a slightly distorted square-pyramidal coordination geometry in which two nitrogen atoms of TBZ or HPB and the carboxylate oxygen and amino nitrogen of glycinate bind in the plane and a water or chloride coordinated at the axial site. The complexes, free ligands, and copper(II) chloride were tested for their ability to inhibit growth of Bacillus subtilis, Staphylococcus aureus, and Salmonella. The results show that the complexes have good antibacterial activities against the microorganisms compared with their ligands and copper(II) chloride.     

Regularities in the Change in Coordination Number of Lanthanide in Aqueous Solutions of LnL Complexes with an Increase in the Atomic Number of the Ln3+Ion

A method is proposed where the values of entropy change upon formation of LnL (H₂O) _n and AnL (H₂O) _n lanthanide and actinide complexes in aqueous solutions are used to determine the coordination numbers of Ln³⁺and An³⁺and the number of coordinated water molecules in these complexes.