Synthesis and characterization of CuII and CoII complexes derived from 2,4,6-tri-(2-pyridyl)-1,3,5-triazine (TPT) by chemical and tribochemical reactions

Four Cu^II and Co^II complexes–[Cu(L₁)Cl₂(H₂O)]3/2H₂O · 1/2EtOH, [Cu(L₁)₂Cl₂]6H₂O, [Co(L₁)Cl₂]3H₂O · EtOH, and [Co₂(L₁)(H₂O)Cl₄]1.5H₂O · EtOH (L₁ = 2,4,6-tri(2-pyridyl)-1,3,5-triazine; TPT)–were synthesized by conventional chemical method and used to synthesize another four metal complexes–[Cu(L₁)I₂(H₂O)]6H₂O, [Cu(L₁)₂I₂]6H₂O, [Co(L₁)I(H₂O)₂]I · 2H₂O, and [Co₂(L₁)I₄(H₂O)₃]–using tribochemical reaction, by grinding it with KI. Substitution of chloride by iodide occurred, but no reduction for Cu^II or oxidation of Co^II. Oxidation of Co^II to Co^III complexes was only observed on the dissolution of Co^II complexes in d₆-DMSO in air while warming. The isolated solid complexes (Cu^II and Co^II) have been characterized by elemental analyses, conductivities, spectral (IR, UV-Vis, ¹H-NMR), thermal measurements (TGA), and magnetic measurements. The values of molar conductivities suggest non-electrolytes in DMF. The metal complexes are paramagnetic. IR spectra indicate that TPT is tridentate coordinating via the two pyridyl nitrogens and one triazine nitrogen forming two five-membered rings around the metal in M : L complexes and bidentate via one triazine nitrogen and one pyridyl nitrogen in ML₂ complexes. In binuclear complexes, L is tridentate toward one Co^II and bidentate toward the second Co^II in [Co₂(L₁)Cl₄]2.5H₂O · EtOH and [Co₂(L₁)I₄(H₂O)₃]. Electronic spectra and magnetic measurements suggest a distorted-octahedral around Cu^II and high-spin octahedral and square-pyramidal geometry around Co^II.     

Synthesis,characterization and electrocatalytic performance of a cobalt(II) complex of <Emphasis Type="Italic">N</Emphasis>-phenylpyridin-2-ylmethanimine

N-phenylpyridin-2-ylmethanimine, HL reacts with CoBr₂ to afford a water-soluble cobalt(II) complex [Co^II(HL)₂Br₂] 1, whose crystal structure has been determined by X-ray diffraction. Electrochemical studies show that this complex can electrocatalyze hydrogen generation from a neutral buffer with a turnover frequency (TOF) of 875.17 mol of hydrogen per mole of catalyst per hour (mol H₂/mol catalyst/h) at an overpotential (OP) of 837.6 mV. Compared with the cobalt complex 1, the previously described nickel(II) complex [Ni(HL)₂Cl₂] (970.45 mol H₂/mol catalyst/h at an OP of 837.6 mV) exhibits more efficient activity for hydrogen evolution.     

Syntheses and crystal structures of phthalato-, succinato-, maleato-, acetylenedicarboxylato-bridged [bis(2-pyridylcarbonyl)amide]copper(II) complexes

Self-assemblies of the 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) and Cu(OH)₂ in the presence of dicarboxylate ligands yielded four new complexes, [Cu₄(bpca)₄(L1)₂(H₂O)₂]·5H₂O (1), [Cu₂(bpca)₂(L2)(H₂O)₂]·2H₂O (2), [Cu₂(bpca)₂(L3)(H₂O)₂]·H₂O (3), and [Cu₂(bpca)₂(L4)(H₂O)₂]·3H₂O (4) (bpca = bis(2-pyridylcarbonyl)amide anion, H₂L1 = phthalic acid, H₂L2 = succinic acid, H₂L3 = maleic acid, H₂L4 = acetylenedicarboxylic acid). Their structures were determined by single-crystal X-ray diffraction analyzes and further characterized by IR spectra and thermogravimetric analyzes. The five-coordinate Cu ions in 1 are bridged by phthalate to form 1-D chains, which are assembled into 3-D frameworks by extensive hydrogen bonds. Compounds 2–4 possess similar structures, built up of [Cu₂(bpca)₂(L)(H₂O)₂] (L = L2 for 2, L3 for 3, L4 for 4) and lattice molecules. The 3-D frameworks of 2–4 are completed by hydrogen bond interactions.     

Three different bonding modes of cyano groups in the coordination polymer [Cu(en)2(H2O)][Cu(en)2Ni2Cu2(CN)10]·2H2O (en is 1,2‐diaminoethane)

Partial reduction of the Cu^II ions in the aqueous system Cu^II–en–[Ni(CN)₄]^2? (1/1/1) (en is 1,2‐di­amino­ethane) yields a novel heterobimetallic mixed‐valence compound, poly­[[aqua­bis(1,2‐di­amino­ethane)copper(II)] [hexa‐μ‐cyano‐tetra­cyano­bis(1,2‐di­amino­ethane)­tricopper(I,II)­dinickel(II)] dihydrate], [Cu(C₂H₈N₂)₂(H₂O)][Ni₂Cu₃(CN)₁₀(C₂H₈N₂)₂]·2H₂O or [Cu(en)₂(H₂O)][Cu(en)₂Ni₂Cu₂(CN)₁₀]·2H₂O. The structure is formed by a negatively charged two‐dimensional array of the cyano complex [Cu(en)₂Ni₂Cu₂(CN)₁₀]_n^2n?, [Cu(en)₂(H₂O)]²⁺ complex cations and water mol­ecules of crystallization. These last are involved in a complicated hydrogen‐bonding system. The cyano groups act as terminal, μ₂‐bridging or μ₃‐bridging ligands.     

Koordinationspolymere 1, 2‐Dithiooxalato‐ und 1, 2‐Dithioquadratato‐Komplexe. Synthese und Strukturen von [BaCr2(bipy)2(1, 2‐dtox)4(H2O)2], [Ni(cyclam)(1, 2‐dtsq)]·2DMF, [Ni(cyclam)Mn(1, 2‐dtsq)2(H2O)2]·2H2O und [H3O][H5O2][Cu(cyclam)]3[Cu2(1, 2‐dtsq)3]2

Coordination Polymeric 1, 2‐Dithiooxalato and 1, 2‐Dithiosquarato Complexes. Syntheses and Structures of [BaCr₂(bipy)₂(1, 2‐dtox)₄(H₂O)₂], [Ni(cyclam)(1, 2‐dtsq)]·2DMF, [Ni(cyclam)Mn(1, 2‐dtsq)₂(H₂O)₂]·2H2₂, and [H₃O][H₅O₂][Cu(cyclam)]₃[Cu₂(1, 2‐dtsq)₃]₂ 1, 2‐Dithioxalate and 1, 2‐dithiosquarate ions have a pair of soft and hard donor centers and thus are suited for the formation of coordination polymeric complexes containing soft and hard metal ions. The structures of four compounds with building blocks containing these ligands are reported: In [BaCr₂(bipy)₂(1, 2‐dtox)₄(H₂O)₂] Barium ions and pairs of Cr(bipy)(1, 2‐dtox)₂ complexes form linear chains by the bisbidentate coordination of the dithiooxalate ligands towards Ba²⁺ and Cr³⁺. In [Ni(cyclam)(1, 2‐dtsq)]·2DMF short NÖH···O hydrogen bonds link the NiS₂N₄‐octahedra with C_2v‐symmetry to an infinite chain. In [Ni(cyclam)Mn(1, 2‐dtsq)₂(H₂O)₂]·2H₂O the 1, 2‐dithiosquarato ligand shows a rare example of S‐coordination towards manganese(II). The sulfur atoms of cis‐MnO₂S₄‐polyedra are weakly coordinated towards the axial sites of square‐planar NiN₄‐centers, thus forming a zig‐zag‐chain of Mn···Ni···Mn···Ni polyhedra. [H₃O][H₅O₂][Cu (cyclam)]₃[Cu₂(1, 2‐dtsq)₃]₂ contains square planar [Cu^II(cyclam)]²⁺ ions and dinuclear [Cu^I₂(1, 2‐dtsq)₃]^4— ions. Here each copper atom is trigonally planar coordinated by S‐donor atoms of the ligands. The Cu…Cu distance is 2.861(4)Å.     

Synthesis,structure, magnetic and catalytic behavior of a dinuclear copper(II) complex with triazendio ligands

A dinuclear copper(II) complex [Cu₂L₄] has been prepared by the reaction of CuCl₂·2H₂O and 1-[(2-iodo)benzene]-3-[benzothiazole] triazene (HL). The complex has been characterized by X-ray crystallography and by physico-chemical and spectroscopic methods. In the solid state, there is a significant antiferromagnetic coupling between the copper(II) centers with a coupling constant (J) of ??558 cm^?1. In homogeneous solution, the complex shows electrocatalytic activities for hydrogen generation from both acetic acid and neutral buffer with a turnover frequency of 50 mol of H₂ per mole of catalyst per hour (mol H₂/mol catalyst/h) at an overpotential (OP) of 941.6 mV, and 502 mol H₂/mol catalyst/h at an OP of 836.7 mV.     

Die Kristallstruktur der hydratisierten Cyanokomplexe NMe4MnII[(Mn, Cr)III(CN)6] · 3 H2O und NMe4Cd[MIII(CN)6] · 3 H2O (MIII = Fe,Co): Verwandte des Berliner Blaus

The Crystal Structure of the Hydrated Cyano Complexes NMe₄Mn^II[(Mn, Cr)^III(CN)₆] · 3 H₂O and NMe₄Cd[M^III(CN)₆] · 3 H₂O (M^III = Fe, Co): Compounds Related to Prussian Blue The crystal structures of the isotypic tetragonal compounds (space group I4, Z = 10) NMe₄Mn^II · [(Mn, Cr)^III(CN)₆] · 3 H₂O (a = 1653.2(4), c = 1728.8(6) pm), NMe₄Cd[Fe(CN)₆] · 3 H₂O (a = 1642.7(1), c = 1733.1(1) pm) and NMe₄Cd[Co(CN)₆] · 3 H₂O (a = 1632.1(2), c = 1722.4(3) pm) were determined by X‐rays. They exhibit ⊥ c cyanobridged layers of octahedra [M^III(CN)₆] and [M^IIN₄(OH₂)₂], which punctually are interconnected also || c to yield altogether a spaceous framework. The M^II atoms at the positions linking into the third dimension are only five‐coordinated and form square pyramids [M^IIN₅] with angles N–M^II–N near 104° and distances of Mn–N: 1 × 214, 4 × 219 pm; Cd–N: 1 × 220 resp. 222, 4 × 226 resp. 228 pm. Further details and structural relations within the family of Prussian Blue are reported and discussed.     

Coordination‐directed and Hydrogen‐bonded Assembly of Supramolecular Architectures Constructed from Diverse Coordination of Linear,Triangular, Tetragonal Pyramid,Trigonal Bipyramid,and Octahedral Mononuclear Units

Reaction of a imidazole phenol ligand 4‐(imidazlo‐1‐yl)phenol (L) with 3d metal salts afforded four complexes, namely, [Ni(L)₆] · (NO₃)₂ ( 1 ), [Cu(L)₄(H₂O)] · (NO₃)₂ · (H₂O)₅ ( 2 ), [Zn(L)₄(H₂O)] · (NO₃)₂ · (H₂O) ( 3 ), and [Ag₂(L)₄] · SO₄ ( 4 ). All complexes are composed of monomeric units with diverse coordination arrangements and corresponding anions. All the hydroxyl groups of monomeric cations are used as hydrogen‐bond donors to form O–H ··· O hydrogen bonds. However, the coordination habit of different metal ions produces various supramolecular structures. The Ni^II atom shows octahedral arrangement in 1 , featuring a 3D twofold inclined interpenetrated network through O–H ··· O hydrogen bond and π–π stacking interaction. The Cu^II atom of 2 displays square pyramidal environment. The O–H ··· O hydrogen bond from the [Cu(L)₄(H₂O)]²⁺ cation and lattice water molecule as well as π–π stacking produce one‐dimensional open channels. NO₃^– ions and lattice water molecules are located in the channels. 3 is a 3D supramolecular network, in which Zn^II has a trigonal bipyramid arrangement. Two different rings intertwined with each other are observed. The Ag^I in 4 has linear and triangular coordination arrangements. The mononuclear units are assembled into a 1D chain by hydrogen bonding interaction from coordination units and SO₄^2– anions.     

Effects of metal centers of complexes supported by S,S′-bis(2-pyridylmethyl)-1,2-thioethane on catalytic activities for electrochemical- and photochemical-driven hydrogen production

S,S′-bis(2-pyridylmethyl)-1,2-thioethane (bpte) reacts with MCl₂ (M = Co, Ni, and Fe) to give three complexes, namely, [Co^II(bpte)Cl₂] ( 1 ), [Ni^II(bpte)Cl₂] ( 2 ), and [Fe^II(bpte)Cl₂] ( 3 ), respectively. They all act as catalysts for proton or water reduction to dihydrogen via electrolysis or photolysis. Under an overpotential of 837.6 mV, the electrolysis of a neutral buffer with complex 1 , 2 , or 3 can provide 418 (±3), 555 (±3), and 243 (±3) moles of hydrogen per mole of catalyst per hour (mol H₂/mol catalyst/h), respectively. Under blue light, together with a photosensitizer and ascorbic acid (H₂A) as a sacrificial electron donor, the photolysis of an aqueous solution (pH 4.5) containing complex 1 , 2 , or 3 can afford 9060 (±5), 24,900 (±5), and 10,630 (±5) moles H₂ per mole of catalyst (mol of H₂ [mol of cat]⁻¹) during 83-h irradiation with an average apparent quantum yield of 7.1%, 24%, and 10%, respectively. The results show that the nickel complex [Ni^II(bpte)Cl₂] exhibits a more efficient activity for hydrogen generation than the iron or cobalt species. These findings may offer a new chemical paradigm for the design of efficient catalysts.     

Highly Selective Enamination of β‐ketoesters Catalyzed by Interlocked [Cu8] and [Cu18] Nanocages

Interlocking cages are of great interest due to their fascinating structures and potential applications. However, the interlocking of different cages has not been previously reported. Herein, quadruply interlocked [Cu₈] and [Cu₁₈] nanocages have been constructed and structurally characterized in cationic metal–organic framework {[Cu^ICu₄^II(XN)₄(PTA)₄(H₂O)₄]0.5 SO₄?5 H₂O?EtOH}_n ( 1 ). 1 can trap the anionic pollutant CrO₄^2? and the radioactive‐contaminant simulant ReO₄^? with an uptake capacity of 83.2 and 218 mg g^?1, respectively. Catalytic investigations reveal 1 is an efficient heterogeneous catalyst for the enamination of ethyl acetoacetate with aniline and the turnover frequency (TOF) can reach a record value of 4000 h^?1. More importantly, 1 represents the first of a catalyst of enamination to exhibit excellent size selectivity on different substrates. The robust catalyst can be reused at least ten times without obvious loss in catalytic activity.     

Synthesis,crystal structures,and properties of copper(II) dicarboxylate complexes with [bis(2-pyridylcarbonyl)amido]

Four new complexes, [Cu₂(Bpca)₂(L¹)(H₂O)₂] · 3H₂O (I), [Cu₂(Bpca)₂(L²)(H₂O)₂] (II), [Cu₂(Bpca)₂(L³)] · 2H₂O (III), [Cu₂(Bpca)₂(L¹)(H₂O)] · 2H₂O (IV) (Bpca = bis(2-pyridylcarbonyl)amido, H₂L¹ = glutaric acid, H₂L² = adipic acid, H₂L³ = suberic acid, H₂L⁴ = azelaic acid) have been synthesized and characterized by single-crystal X-ray diffraction methods (CIF files CCDC nos. 1432836 (I), 1432835 (II), 817411 (III), and 817412 (IV)), elemental analyses, IR spectra. Structural analyses reveal that compounds I, II, and IV have similar structures [Cu(Bpca)]⁺ units bridged by dicarboxylate forming dinuclear units, whereas the dinuclear of compound III are edge-shared through two carboxylate oxygen atoms of different suberate anions. Hydrogen bonds are response for the supramolecular assembly of compounds I to IV. The temperature-dependent magnetic property of III was also investigated in the temperature range of 2 to 300 K, and the magnetic behaviour suggests weak antiferromagnetic coupling exchange.     

2‐Amino‐5‐(2‐pyridyl)‐thiadiazole as Bidentate Ligand

The amino substituted bidentate chelating ligand 2‐amino‐5‐(2‐pyridyl)‐1,3,4‐thiadiazole (H₂ L ) was used to prepare 3:1‐type coordination compounds of iron(II), cobalt(II) and nickel(II). In the iron(II) perchlorate complex [Fe^II(H₂ L )₃](ClO₄)₂·0.6MeOH·0.9H₂O a 1:1 mixture of mer and fac isomers is present whereas [Fe^II(H₂ L )₃](BF₄)₂·MeOH·H₂O, [Co^II(H₂ L )₃](ClO₄)₂·2H₂O and [Ni^II(H₂ L )₃](ClO₄)₂·MeOH·H₂O feature merely mer derivatives. Moessbauer spectroscopy and variable temperature magnetic measurements revealed the [Fe^II(H₂ L )₃]²⁺ complex core to exist in the low‐spin state, whereas the [Co^II(H₂ L )₃]²⁺ complex core resides in its high‐spin state, even at very low temperatures.     

Crystal Structures of [Cu2(bpy)2(H2O)(OH)2(SO4)]·4H2O and [Cu(bpy)(H2O)2]SO4 with bpy = 2, 2′‐Bipyridine

Two sulfato Cu^II complexes [Cu₂(bpy)₂(H₂O)(OH)₂(SO₄)]· 4H₂O ( 1 ) and [Cu(bpy)(H₂O)₂]SO₄ ( 2 ) were synthesized and structurally characterized by single crystal X—ray diffraction. Complex 1 consists of the asymmetric dinuclear [Cu₂(bpy)₂(H₂O)(OH)₂(SO₄)] complex molecules and hydrogen bonded H₂O molecules. Within the dinuclear molecules, the Cu atoms are in square pyramidal geometries, where the equatorial sites are occupied by two N atoms of one bpy ligand and two O atoms of different μ₂—OH groups and the apical position by one aqua ligand or one sulfato group. Through intermolecular O—H···O and C—H···O hydrogen bonds and intermolecular π—π stacking interactions, the dinuclear complex molecules are assembled into layers, between which the hydrogen bonded H₂O molecules are located. The Cu atoms in 2 are octahedrally coordinated by two N atoms of one bpy ligand and four O atoms of two H₂O molecules and two sulfato groups with the sulfato O atoms at the trans positions and are bridged by sulfato groups into ¹[Cu(bpy)(H₂O)₂(SO₄)_2/2] chains. Through the interchain π—π stacking interactions and interchain C—H···O hydrogen bonds, the resulting chains are assembled into bi—chains, which are further interlinked into layers by O—H···O hydrogen bonds between adjacent bichains.     

Synthesis,Structure, Magnetic and Electrochemical Properties of a Dinuclear Copper Complex

A material for both magnetic coupling and electrocatalytic hydrogen evolution based on the copper complex, [(L)₂Cu₂] is formed by the reaction of CuCl₂ · 2H₂O with the tetradentate ligand 6‐(3‐aminomethylpropanol)‐2‐tert‐buty‐4‐methylphenol (H₂L), which is prepared by reaction of 2‐tert‐butyl‐4‐methylphenol, 3‐amino‐1‐propanol, and formaldehyde. Structural studies show that in the solid state complex 1 exhibits strong antiferromagnetic exchange interaction between copper(II) ions mediated by oxygen‐bridges. In liquid, 1 becomes a monomer, and can electrocatalyze hydrogen generation both from acetic acid with a turnover frequency (TOF) of 101.70 mol of hydrogen per mole of catalyst per hour at an overpotential (OP) of 941.6 mV (in DMF), and a natural buffer with a TOF of 650 mol of hydrogen per mole of catalyst per hour at an OP of 836.7 mV.     

Transition Metal Ion-Directed Coordination Polymers with Mixed Ligands: Synthesis,Structure, and Photocatalytic Activity for Hydrogen Production and Rhodamine B Degradation

Three mixed-ligand transition metal coordination polymers with the formula of {[Cu^I₂Cu^II(tpt)₂(L)] · 15H₂O}_n ( 1 ) and {[M₂(H₂O)₅(tpt)(L)] · 6H₂O}_n [M = Ni for 2 and Co for 3 ; tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine and L = 3,3'-disulfonyl-4,4'-biphenyldicarboxylate] were hydrothermally synthesized by varying the cheap paramagnetic metal ions and used as photocatalysts for hydrogen evolution from water splitting and rhodamine B (RhB) degradation. Single-crystal structural determinations reveal that 1 is a robust pillared-layer framework with unusual 72-membered {Cu₆(tpt)₆} macrocycle-based layers supported by tetratopic L^4– connectors. Both 2 and 3 are isostructural (4 4) sheets with octahedral Ni^II and Co^II ions extended by ditopic L^4– and tpt linkages, in which the third pyridyl group of tpt is capped by pentahydrated metal ions. Due to the narrowed bandgap and good charge transport of the mixed-valence Cu^I/II centers, 1 exhibits improved dual-functional catalytic activities than 2 and 3 with the visible-light-driven hydrogen evolution rate and RhB degradation efficiency up to 588 μmol · g^–1 · h^–1 and 72 % after 180-minute irradiation. These interesting results indicate the importance of the metal ions and the dimensionality of the coordination polymers on the activity of the non-Pt coordination polymer photocatalytic systems.     

The assembly of POM-induced inorganic–organic hybrids based on copper ions and mixed ligands

Three inorganic–organic hybrid materials based on Keggin-type polyoxometalates (POMs), [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂][PMo₁₂O₄₀]₂·2H₂O (1), [Cu^II(phen)₂(H4,4′bipy)][PW₁₂O₄₀]·H₂O (2), and [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂](H₂4,4′-bipy)_0.5·3H₂O (3) (phen = 1,10-phenanthroline, 4,4′-bipy = 4,4′-bipyridine), were synthesized using different POMs in the hydrothermal conditions. Compounds 1–3 were characterized by single-crystal X-ray diffraction, IR spectra, elemental analyses, powder X-ray diffraction analyses, and thermogravimetric analyses. Compound 1 presents a two-dimensional (2-D) network containing the Keggin-type [PMo₁₂O₄₀]^3? anion and dinuclear metal–organic units [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂]³⁺. Compound 2 is a 2-D architecture constructed from a [PW₁₂O₄₀]^3? and mononuclear metal–organic units [Cu^II(phen)₂(H4,4′-bipy)]³⁺. In 3, the [BW₁₂O₄₀]^5? anions link [Cu^II₂(phen)₂(4,4′-bipy)] units to form a one-dimensional (1-D) chain [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂]; the 1-D chain connects with protonated 4,4′-bipy ligands and lattice waters, yielding a 2-D layer. Fluorescence spectra, UV–vis spectra, and electrochemical properties of 1–3 have been investigated.     

Synthesis, structures, and magnetic properties of carboxylate-bridged trinuclear complexes based on low-spin manganese(III)/iron(III) building blocks

Four linear trinuclear transition metal complexes have been prepared and characterized. The complexes [M^II(MeOH)₄][Fe^III(L)₂]₂·2MeOH (M = Fe (1) or Ni (2)), [Co^II(EtOH)₂(H₂O)₂][Fe^III(L)₂]₂·2EtOH (3), and [Mn^II(phen)₂][Mn^III(L)₂]₂·4MeOH (4) (H₂L = ((2-carboxyphenyl)azo)-benzaldoxime, phen = 1,10-phenanthroline) possesses a similar syn–anti carboxylate-bridged structure. The terminal Fe(III) or Mn(III) ions are low spin, and the central M(II) ions are high spin. Magnetic measurements show that antiferromagnetic interactions were present between the adjacent metal ions via the syn–anti carboxylate bridges. The antiferromagnetic coupling between low-spin Fe(III) and Ni(II) is unusual, which has been tentatively assigned to the structural distortion of Fe(III).     

A lvt‐type Framework [Cu2(tza)4]·ClO4·4H2O Derived from 1H‐tetrazole‐1‐acetic Acid

The reaction of 1H‐tetrazole‐1‐acetic acid (Htza) and perchloric acid with cuprous chloride with slow evaporation at room temperature gave a novel 3D porous Cu^II coordination polymer, [Cu₂(tza)₄] · ClO₄ · 4H₂O ( 1 ), (tza = tetrazole‐1‐acetate). The structure exhibits an unusual 3D microporous coordination framework built up by four coordinated Cu^II nodes and bidentate bridging tza ligands with lvt‐type topology. Furthermore, the magnetic properties of complex 1 were also investigated.     

Cobaltchelate als Hydrierkatalysatoren. II). Hydridbildung beim [Co(dmgH)2]- und [Co(dpnH)]+ -Komplex

Cobalt Chelates for Hydrogenation Catalysts. II. Hydride Formation with [Co(dmgH)₂] and [Co(dpnH)]⁺ In the presence of benzil as scavanger for the hydridocomplexes [Co(dpnH)]⁺ and [Co(dmgH)₂] the hydride formation in water/n-propanol (50% v/v) becomes the rate determining step, and the ligand hydrogenation is completely suppressed in the case of [Co(dpnH)]⁺, but only partially in the case of [Co(dmgH)₂]. The rate of hydride formation in both cases is 2^nd order with respect to the complex, and the activation parameters ([Co(dmgH)₂]: ΔH^≠ = 48.4 ± 1.0 kJ · mol–¹, ΔS^≠ = ?57.4 ± 3.4J · mol^?1 · K^?1, [Co(dpnH)]⁺: ΔH^≠ = 52.7 = 0.4 kJ · mol^?1, ΔS^≠ = ?59.8 ± 1.2J · mol^?1 · K^?1) indicate a H₂-activation by homolytic splitting for both complexes. Some sources of error and possible causes for the missing activity of [Co(tim)]²⁺ are discussed.     

2D Compound Constructed by Cu3 Units with Mixed Azido and Tetrazole Double Bridges: Synthesis,Structure, and Theoretical Study on Magnetic Properties

The two‐dimensional (2D) layer Cu^II compound [Cu₃(L)₂(N₃)₄] ( 1 ) [L = 2‐amino‐3‐(5‐tetrazole)‐methyate‐N‐pyridine] was synthesized by in‐situ hydrothermal reaction of CuCl₂ · 2H₂O, NaN₃, and 3‐(5‐tetrazole)‐methyate‐N‐pyridine. The central Cu1 and Cu2 atoms are located in five‐coordinate and six‐coordinate arrangements, respectively. Three Cu^II ions are linked by mixed double EO (end‐on)‐azido‐tetrazole bridges to give trinuclear Cu^II clusters, which are further extended by EE (end‐to‐end) azido bridges to form 2D metal‐organic layers. The magnetic exchange interactions in complex 1 were investigated by DFT calculations, and the calculated exchange interaction (J = –849 cm^–1) revealed that the double EO‐azido‐tetrazole bridges transmit antiferromagnetic coupling between Cu^II ions.