Structural and Spectral Study of Copper(II) Complexes of Pyridil bis{3‐piperidyl‐, bis{hexamethyleneiminyl‐, bis{N(4)‐diethyl‐, and bis{N(4)‐dipropylthiosemicarbazones}

Pyridil bis(N(4)‐substituted thiosemicarbazones) have been prepared in which the substituents in place of the NH₂ group in the thiosemicarbazone moieties are piperidinyl (H₂Plpip), hexamethyleneiminyl (H₂Plhexim), diethylaminyl (H₂Pl4DE), and dipropylaminyl (H₂Pl4DP). IR, electronic, mass, and ESR spectra of their copper(II) complexes are reported. Crystal structure determinations of H₂Pl4DE and three of the copper(II) complexes of formula [Cu(Plpip)], [Cu(Plhexim)] and [Cu(Pl4DE)]₂ · 2[Cu(Pl4DE)], are included. H₂Pl4DE lacks hydrogen bonding between the thiosemicarbazone moieties, but each moiety is in the Z configuration form with hydrogen bonding from the thiosemicarbazone moieties to the pyridyl nitrogen atoms. The crystal used for the structure determination of [Cu(Plhexim)] was isolated from an electrochemical preparation. In all the new compounds the deprotonated ligands are N,N,S,S‐tetradentate, coordinating to the copper(II) centre through their azomethine nitrogen atoms and their thiocarbonyl sulfur atoms.     

Bis{μ‐6,6′‐dimethoxy‐2,2′‐[propane‐1,2‐diylbis(iminomethylene)]diphenolato}bis[aquacopper(II)] dihydrate

In the title compound, [Cu₂(C₁₉H₂₄N₂O₄)₂(H₂O)₂]·2H₂O, the asymmetric unit consists of one half of the bis{μ‐6,6′‐dimethoxy‐2,2′‐[propane‐1,2‐diylbis(iminomethylene)]diphenolato}bis[aquacopper(II)] complex and two water molecules. Two Cu^II centres are bridged through a pair of phenolate groups, resulting in a complex with a centrosymmetric structure, with the centre of inversion at the middle of the Cu₂O₂ plane. The Cu atoms are in a slightly distorted square‐pyramidal coordination environment (τ = 0.07). The average equatorial Cu—O bond length and the axial Cu—O bond length are 1.928 (3) and 2.486 (3) Å, respectively. The Cu—O(water) bond length is 2.865 (4) Å, so the compound could be described as having a weakly coordinating water molecule at each Cu^II ion and two solvent water molecules per dimetallic unit. The Cu...Cu distance and Cu—O—Cu angle are 3.0901 (10) Å and 87.56 (10)°, respectively. The molecules are linked into a sheet by O—H...O and C—H...O hydrogen bonds parallel to the [001] plane.     

{μ‐PbSe}: A Heavy CO Homologue as an Unexpected Ligand

Reactions of [K(18‐crown‐6)]₂[Pb₂Se₃] and [K([2.2.2]crypt)]₂[Pb₂Se₃] with [Rh(PPh₃)₃Cl] in en (ethane‐1,2‐diamine) afforded ionic compounds with [Rh₃(PPh₃)₆(μ₃‐Se)₂]^? and [Rh₃(CN)₂(PPh₃)₄(μ₃‐Se)₂(μ‐PbSe)]^3? anions, respectively. The latter contains a PbSe ligand, a rather uncommon homologue of CO that acts as a μ‐bridge between two Rh atoms. Quantum chemical calculations yield a significantly higher bond energy for PbSe than for CO, since the size of the ligand orbitals better matches the comparably rigid Rh‐Se‐Rh angles and the resulting Rh???Rh distance. To rationalize the bent coordination of the ligand, orbitals with significant ligand contributions and their dependence on the bonding angle were investigated in detail.     

Copper(II) and Manganese(II) Coordination Polymers of 5‐Aminobenzene‐1,3‐dicarboxylic Acid (abdc) Ligand,Structural Studies of [Cu(μ4‐abdc) (DMF)]n and {[Mn(μ4‐abdc)(H2O)]·H2O}n

Two new two‐dimensional Cu^II and Mn^II coordination polymers of 5‐aminobenzene‐1,3‐dicarboxylic acid (abdc) ligand, [Cu(μ₄‐abdc)(DMF)]_n and {[Mn(μ₄‐abdc)(H₂O)]·H₂O}_n, have been synthesized and characterized by elemental analysis and IR‐ spectroscopy. The single crystal X‐ray analyses show that the coordination number in these complexes is six, CuO₅Cu and MnO₅N. The compounds are structurally diverse and the coordination polymer obtained from copper show significant copper–copper interaction while the manganese coordination polymer shows Mn–N_amino bond.     

Enantiomeric bis(μ‐N,N′‐hexamethylenedisalicylaldiminato)dicopper(II) complexes

The title dimeric complex, bis{μ‐2,2′‐[hexane‐1,6‐diyl­bis(nitrilo­methyl­idyne)]­diphenolato‐1:2κ⁴O,N:N′,O′}dicopper(II),[Cu₂(C₂₀H₂₂N₂O₂)₂], has been investigated by single‐crystal X‐ray diffraction, by thermogravimetric analysis and differential scanning calorimetry, and also by FT–IR spectroscopy. Different synthetic and crystallization procedures gave crystals which were quite different in appearance, and it was initially thought that these were different polymorphic forms. Subsequent structure determination showed, in fact, serendipitous preparation of crystals in the P4₁ space group by one method and in space group P4₃ by the other. In these enantiomorphic structures, the Cu atoms have a distorted flattened tetrahedral coordination, with Cu—N and Cu—O distances in the ranges 1.954 (4)–1.983 (4) and 1.887 (4)–1.903 (4) Å, respectively.     

Synthesis,Characterization and Magnetic Studies of μ‐Oxamido Copper (II) ‐ Chromium (III) Heterodinuclear Complexes

Three new μ‐oxamido‐bridged heterodinuclear copper (II)‐chromium (III) complexes formulated [Cu(Me₂oxpn)Cr‐(L)₂](NO₃)₃, where Me₂oxpn denotes N,N'‐bis(3‐amino‐2, 2‐dimethylpropyl)oxamido dianion and L represents 5‐methyl‐1,10‐phenanthroline (Mephen), 4,7‐diphenyl‐1,10‐phenanthroline (Ph₂phen) or 2,2′‐bipyridine (bpy), have been synthesized and characterized by elemental analyses, IR and electronic spectral studies, magnetic moments of room‐temperature and molar conductivity measurements. It is proposed that these complexes have oxamido‐bridged structures consisting of planar copper (II) and octahedral chromium (III) ions. The variable temperature magnetic susceptibilities (4.2–300 K) of complexes [Cu(Me₂oxpn)Cr(Ph₂phen)₂](NO₃)₃ (1) and [Cu(Me₂oxpn)Cr(Mephen)₂] (NO₃)₃ (2) were further measured and studied, demonstrating the ferromagnetic interaction between the adjacent chromium (III) and copper (II) ions through the oxamido‐bridge in both complexes 1 and 2. Based on the spin Hamiltonian, ? = ‐ 2J?₁ · ?₂, the exchange integrals J were evaluated as + 21.5 an^?1 for 1 and + 22.8 cm^?1 for 2.     

Structure and Magnetic Properties of Mononuclear Copper(II) Complexes with 2,2‐Bipyrimidine, 2,3‐Bis(2‐pyridyl)pyrazine,and 4‐Terpyridone Based Ligands

Four new complexes of [Cu(bpm)(ox)(H₂O)] ( 1 ), [Cu(tpd)(dca)(H₂O)] ( 2 ), [Cu(bppz)(N₃)₂] ( 3 ), and [Cu(bpm)₂(μ_1,3‐N₃)(N₃)] ( 4 ) (bpm = 2,2′‐bipyrimidine, bppz = 2,3‐bis(2‐pyridyl)pyrazine, tpd = 4‐terpyridone, dca = dicyanamide, ox = oxalate) have been prepared and characterized by X‐ray single‐crystal analysis and variable‐temperature magnetic measurements. Compounds 1–4 are essentially mononuclear Cu(II) complexes. However, in complex 1 , Cu(II) it was found that intermolecular hydrogen bonding through between H₂O and ox formed 1‐D chain structure. In complex 2 it was found that the hydrogen bonding between H₂O and tpd of the next molecule led to for a binuclear Cu(II) complex. In complex 3 , two nitrogen atoms, one of the pyridyl group of bppz and one of N₃^? ligands, are weakly coordinated to neighbor Cu(II) ion thus leading to formation of a 1‐D chain structure. In complex 4 , one nitrogen atom of terminated N₃^? is weakly coordinated to the neighbor Cu(II) site to form a 1‐D polymeric structure. The magnetic susceptibility measurements indicate that complex 1 and 4 exhibit a weak antiferromagnetic interaction whereas a ferromagnetic coupling has been established for complexes 2 and 3 .     

Synthesis and characterization of μ-oxamido copper(Ⅱ)-iron(Ⅱ) heterobinuclear complexes with an antiferromagnetic exchange interaction

Four new u-oxamido heterobinuclear complexes have been synthesized and identified as [Cu(oxap)Fe(L)2]SO4, where oxap denotes the N, N'-bis(2-aminopropyl)oxamido dianion and L represents diaminoethane (en); 1,3-diaminopropane (pn); 1,2-diaminopropane (ap) and 2,9-dimethyl-1,10-phenanthroline (Me2-phen). Based on the elemental analyses, spectroscopic studies, magnetic moments (at room temperature) and molar conductivity measurements, extended oxamido-bridged structures consisting of a copper(Ⅱ) and an iron(Ⅱ) ions, which have a square planar environment and an octahedral environment, respectively, are proposed for these complexes. Complexes [Cu(oxap)Fe(en)2]SO4 (1) and [Cu(oxap)Fe(pn)2]SO4 (2) have been characterized by variable temperature magnetic susceptibility (4.2~300 K) and the observed data were least-squares fitted to the susceptibility equation derived from the spin Hamiltonian including single-ion zero-field interaction for the iron(Ⅱ) ion, H=-2JS1.S2-DSzl2, giving the exchange integrals J=-2     

Darstellung und spektroskopische Charakterisierung von Kupfer(II)- und Nickel(II)-tricyanmethanid-Komplexen mit Imidazol-Derivaten – Kristallstruktur von [Cu{C(CN)3}2(2-meiz)2]

Synthesis and Spectroscopic Characterization of Copper(II) and Nickel(II) Tricyanomethanide Complexes with Imidazoles – Crystal Structure of [Cu{C(CN)₃}₂(2-meiz)₂] The copper(II) and nickel(II) tricyanomethanide complexes with imidazoles of the type [Cu{C(CN)₃}₂L₄], [L = 2- or 4-methylimidazole (meiz)] and [M{C(CN)₃}₂L₂] [M = Cu, L = imidazole (iz), 2- or 4-meiz; M = Ni, L = iz, 2- or 4-meiz] were prepared and characterized by electronic, infrared, and – some of them – by ESR spectroscopy. The structure [Cu{C(CN)₃}₂(2-meiz)₂], solved by X-ray crystallographic analysis, shows a two-dimensional network with unsymmetric C(CN)₃-bridges between the Cu^II atoms. Polymeric structures with bridging C(CN)₃-groups were identified by means of spectroscopic methods also for the other [M{C(CN)₃}₂L₂] complexes. On the other hand, for the complexes [M{C(CN)₃}₂L₄] follow molecular structures, in which monodentate C(CN)₃ ligands are present. All compounds under investigation show a tetragonal-bipyramidal geometry with various degree of tetragonal distortion.     

catena‐Poly­[[[1,8‐bis(2‐hydroxy­ethyl)‐1,3,6,8,10,13‐hexa­aza­cyclo­tetra­decane]copper(II)]‐μ‐cyano‐[tri­cyano­nitro­soiron(III)]‐μ‐cyano]

The bimetallic title complex, [CuFe(CN)₅(C₁₂H₃₀N₆O₂)(NO)] or [Cu(L)Fe(CN)₅(NO)] [where L is 1,8‐bis(2‐hydroxy­ethyl)‐1,3,6,8,10,13‐hexa­aza­cyclo­tetra­decane], has a one‐dimensional zigzag polymeric –Cu(L)–NC–Fe(NO)(CN)₃–CN–Cu(L)– chain, in which the Cu^II and Fe^II centres are linked by two CN groups. In the complex, the Cu^II ion is coordinated by four N atoms from the L ligand [Cu—N(L) = 1.999 (2)–2.016 (2) Å] and two cyanide N atoms [Cu—N = 2.383 (2) and 2.902 (3) Å], and has an elongated octahedral geometry. The Fe^II centre is in a distorted octahedral environment, with Fe—N(nitroso) = 1.656 (2) Å and Fe—C(CN) = 1.938 (3)–1.948 (3) Å. The one‐dimensional zigzag chains are linked to form a three‐dimensional network via N—H⋯N and O—H⋯N hydrogen bonds.     

The bimolecular structure of aquahexa‐μ‐chlorido‐μ4‐oxido‐tris(tetrahydrofuran‐κO)tetracopper(II)–hexa‐μ‐chlorido‐μ4‐oxido‐tetrakis(tetrahydrofuran‐κO)tetracopper(II)–tetrahydrofuran (2/1/4)

The title bimolecular structure, [Cu₄Cl₆O(C₄H₈O)₃(H₂O)]₂[Cu₄Cl₆O(C₄H₈O)₄]·4C₄H₈O, at 100 K has monoclinic (P2₁/c) symmetry. The structure contains nine symmetry‐independent molecules expressed in simplest molecular form as 6[Cu₄Cl₆O(C₄H₈O)₃(H₂O)·2(C₄H₈O)]:3Cu₄Cl₆O(C₄H₈O)₄. The compound exhibits a supercell (smaller than the unit cell based on weak reflections) structure due to pseudotranslational symmetry. The structure displays O—H...O hydrogen bonding between bound water ligands and tetrahydrofuran (THF) solvent molecules. The structure exhibits disorder for 12 of the THF molecules, of which seven are ligated to Cu and five are hydrogen bonded to H₂O ligands.     

Poly­[[bis­(pyridine‐κN)copper(II)]‐μ3‐5‐hydroxy­isophthalato‐κ3O:O′:O′′]

In the title compound, [Cu(C₈H₄O₅)(C₅H₅N)₂]_n or [Cu(OH‐BDC)(py)₂]_n (where OH‐H₂BDC is 5‐hydroxy­isophthalic acid and py is pyridine), the Cu atoms are coordinated by two N atoms from the pyridine ligands and by three O atoms from hydroxy­isophthalate ligands in a highly distorted triangular bipyramidal environment, with Cu—O distances in the range 1.941 (4)–2.225 (5) Å and Cu—N distances of 2.014 (6) and 2.046 (6) Å. The [Cu(OH‐BDC)]_n two‐dimensional network is built up from interlocking 22‐, 15‐ and eight‐membered rings via sharing of Cu atoms and O—H⋯O hydrogen bonds. Consolidation of the packing structure is achieved by edge‐ or point‐to‐face C—H⋯π interactions and offset or slipped π–π stacking interactions.     

Poly[diaquabis(μ3‐2,2‐dimethylpropanedioato)calcium(II)copper(II)]

The title complex, [CaCu(C₅H₆O₄)₂(H₂O)₂]_n, is the first heterobimetallic complex based on a substituted malonate dianion. The Cu^II cation and two independent 2,2‐dimethylmalonate (or 2,2‐dimethylpropanedioate) dianions build up a robust dianionic [Cu(C₅H₆O₄)₂]²⁻ complex, which acts as a building block to coordinate to four Ca²⁺ cations. Each Cu^II centre is in a four‐coordinate square plane of dimethylmalonate O atoms, while each Ca^II atom is in an eight‐coordinate distorted bicapped trigonal–prismatic environment of six O atoms from four different dimethylmalonate groups and two water molecules. This arrangement creates a two‐dimensional layer connectivity of the structure. The dianionic [Cu(C₅H₆O₄)₂]²⁻ units are involved in different intermolecular hydrogen‐bonding interactions with water molecules via the formation of hydrogen‐bonded rings of graph sets R₁²(8) and R(6) within this layer. The crystal was nonmerohedrally twinned by rotation about [011] with a major twin volume fraction of 0.513 (3).     

Bis­[μ‐3{5}‐(2‐pyridyl)­pyrazolido]­bis­[(aceto­nitrile)copper(II)] diperchlorate

The title compound, [Cu₂(C₈H₆N₃)₂(C₂H₃N)₂](ClO₄)₂, con­tains a centrosymmetric dinuclear dication, with square‐pyrami­dal Cu^II centres linked by two 1,2‐pyrazolide bridging groups. There is a weak apical interaction between each Cu ion and a perchlorate O atom.     

Polytellurides and Polyselenides – Compounds Containing $_{\infty}^{1}\rm [Te_{6}-Te_{4}]^{4-}$ and [Sn(Se4)3]2− Anions

The reactions of the Zintl phase K₂Cs₂Sn₉ with elemental tellurium and selenium in ethylenediamine have been investigated. From the reaction of K₂Cs₂Sn₉ with elemental tellurium [K‐(2,2,2‐crypt)]₄Te₆Te₄ ( 2 ) and [K‐(2,2,2‐crypt)]₂Sn₂Te₃ ( 3 ) were obtained, whereas the reaction of K₂Cs₂Sn₉ with elemental selenium led to the formation of [K‐(2,2,2‐crypt)]₂Sn(Se₄)₃ ( 4 ) and [K‐(2,2,2‐crypt)]₂Cs₂Sn₂Se₆·2en ( 5 )¹⁾. Compounds 2 , 4 , 5 have been characterized by single crystal X‐ray structure determination.     

Poly[[aqua­copper(II)]‐μ‐adamantane‐1,3‐diacetato]

In the title compound, [Cu(C₁₄H₁₈O₄)(H₂O)]_n, each Cu^II atom bonds to four O atoms of four adamantanediacetate (ada) ligands in equatorial positions and an O atom from a water mol­ecule in the apical position. Two adjacent Cu^II atoms form a paddle‐wheel unit with four ada ligands. The distance between the two Cu atoms is 2.5977 (3) Å. A crystallographic inversion center is located at the center of the Cu–Cu core. Each Cu₂(ada)₄ paddle‐wheel further bonds to four adjacent identical paddle‐wheel units, generating a two‐dimensional layered structure of Cu(ada)(H₂O) with a 4⁴ topology.     

Poly[[aqua‐μ3‐2,2‐dimethylmalonato‐copper(II)] monohydrate] and poly[aqua‐μ3‐2,2‐dimethylmalonato‐copper(II)]

The coordination mode of the dimethylmalonate ligand in the two title Cu^II complexes, {[Cu(C₅H₃O₄)(H₂O)]·H₂O}_n, (I), and [Cu(C₅H₃O₄)(H₂O)]_n, (II), is the same, with chelated six‐membered, bis‐monodentate and bridging bonding modes. However, the coordination environment of the Cu^II atoms, the connectivity of their metal–organic frameworks and their hydrogen‐bonding interactions are different. Complex (I) has a perfect square‐pyramidal Cu^II environment with the aqua ligand in the apical position, and only one type of square grid consisting of Cu^II atoms linked via carboxylate bridges to three dimethylmalonate ligands, with weak hydrogen‐bond interactions within and between its two‐dimensional layers. Complex (II) has a coordination geometry that is closer to square pyramidal than trigonal bipyramidal for its Cu^II atoms with the aqua ligand now in the basal plane. Its two‐dimensional layer structure comprises two alternating grids, which involve two and four different dimethylmalonate anions, respectively. There are strong hydrogen bonds only within its layers.     

Spectral and Structural Studies of the Copper(II) Complexes of 3, 4‐Hexanedione Bis(3‐azacyclothiosemicarbazones)

Copper(II) complexes of 3, 4‐hexanedione bis(piperidyl‐ and bis(hexamethyleneiminylthiosemicarbazone), H₂Hxpip and H₂Hxhexim, respectively, have been prepared and studied spectroscopically. The bis(thiosemicarbazones) have been characterized by their melting points, as well as IR, electronic and ¹H NMR spectra. Upon formation of their copper(II) complexes, loss of the hydrazinic hydrogen atoms occurs, and the ligands coordinate as dianionic, tetradentate N₂S₂ ligands. The crystal structures of H₂Hxpip, its 4‐coordinate copper(II) complex, [Cu(Hxpip)], and the related [Cu(Hxhexim)] have been determined by single crystal x‐ray diffraction. The nature of the four‐coordinate copper(II) complexes have also been characterized by ESR, IR, and electronic spectroscopy, as well as magnetic moments and elemental analyses.     

Poly[bis{μ2‐4‐[3,5‐bis(pyridin‐4‐yl)phenyl]pyridine}nona‐μ2‐oxido‐tetraoxidocopper(II)tetramolybdenum(VI)]

The title compound, [CuMo₄O₁₃(C₂₁H₁₅N₃)₂]_n, was synthesized by the reaction of ammonium molybdate, copper acetate and 4‐[3,5‐bis(pyridin‐4‐yl)phenyl]pyridine (DPPP) in an aqueous medium under hydrothermal conditions. The two unique molybdenum centers and the copper center adopt MoO₄ tetrahedral, MoO₅N octahedral and CuO₄N₂ octahedral geometries, respectively. These polyhedra are connected to each other through corner‐sharing to form a two‐dimensional Cu–Mo–O layer, which is further linked by the DPPP ligands to form the three‐dimensional inorganic–organic hybrid framework.     

Mono- and Binuclear Copper(II) and Nickel(II) Complexes with the 3,6-Bis(picolylamino)-1,2,4,5-Tetrazine Ligand

Four new compounds of formulas [Cu(hfac)₂(L)] (1), [Ni(hfac)₂(L)] (2), [{Cu(hfac)₂}₂(µ-L)]·2CH₃OH (3) and [{Ni(hfac)₂}₂(µ-L)]·2CH₃CN (4) [Hhfac = hexafluoroacetylacetone and L = 3,6-bis(picolylamino)-1,2,4,5-tetrazine] have been prepared and their structures determined by X-ray diffraction on single crystals. Compounds 1 and 2 are isostructural mononuclear complexes where the metal ions [copper(II) (1) and nickel(II) (2)] are six-coordinated in distorted octahedral MN₂O₄ surroundings which are built by two bidentate hfac ligands plus another bidentate L molecule. This last ligand coordinates to the metal ions through the nitrogen atoms of the picolylamine fragment. Compounds 3 and 4 are centrosymmetric homodinuclear compounds where two bidentate hfac units are the bidentate capping ligands at each metal center and a bis-bidentate L molecule acts as a bridge. The values of the intramolecular metal···metal separation are 7.97 (3) and 7.82 Å (4). Static (dc) magnetic susceptibility measurements were carried out for polycrystalline samples 1–4 in the temperature range 1.9–300 K. Curie law behaviors were observed for 1 and 2, the downturn of χ_MT in the low temperature region for 2 being due to the zero-field splitting of the nickel(II) ion. Very weak [J = −0.247(2) cm⁻¹] and relatively weak intramolecular antiferromagnetic interactions [J = −4.86(2) cm⁻¹] occurred in 3 and 4, respectively (the spin Hamiltonian being defined as H = −JS₁·S₂). Simple symmetry considerations about the overlap between the magnetic orbitals across the extended bis-bidentate L bridge in 3 and 4 account for their magnetic properties.