Long-range superexchanged magnetic interaction observed in heterometallic complex: {[Fe(Tpms)(CN)3][Mn(H2O)2(DMF)2]} · DMF

A new tri-cyanometalate building block for heterometallic complexes, [PPh₄]₂[Fe^II(Tpms)(CN)₃] (2) (PPh₄ = tetraphenylphosphonium; Tpms = tris(pyrazolyl) methanesulfonate), has been prepared. Using it as a building block, a one-dimensional chain compound, {[Fe^II(Tpms)(CN)₃][Mn^II(H₂O)₂( DMF)₂]} · DMF (3), has been synthesized and structurally characterized. The magnetic properties of 3 correspond to a ferromagnetic chain with weak long-range superexchanged magnetic interaction between the high-spin manganese(II) ions.     

Protonation and Zn(II) complexation with versatile valine and glycylglycine N-pyrimidines derivatives: crystal structures of layered {[Zn(HL1)2] · 2H2O}n and [Zn(HL2)2(H2O)4]

Protonation and Zn(II) complexation of N-substituted amino acids, valine (H₂L1) and glycylglycine (H₂L2), with 4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxopyrimidin-2-yl as substituent, were studied by potentiometric and UV-Vis measurements. Bianions L1 and L2 suffer three protonation steps in aqueous medium corresponding to the amide and carboxylate groups of the amino acidic moiety, and the nitrogen atom of the nitroso group of the pyrimidine fragment. Both ligands form mononuclear Zn(II) complexes in aqueous solutions. The binding donor groups are the nitroso and/or the oxo groups of the pyrimidinic moiety or the carboxylate group, depending on whether the ligands are neutral or anionic, respectively. Weak metal-to-ligand interactions were observed independently of the functionality used by the corresponding ligand on bonding to Zn(II). The reaction of ZnCl₂ with the monodeprotonated ligands (1:1) yields a polynuclear 2D {[Zn(HL1)₂] · 2H₂O}_n and a mononuclear [Zn(HL2)₂(H₂O)₄] complexes, showing the influence of the susbtituent on the amino acids fragment as well as the versatility of this class of compounds when acting as ligands.     

Synthesis, magnetic properties and crystal structures of two compounds: [Cu(en)(H2O)]2[Fe(CN)6]·4H2O and [Cu(en)2][KFe(CN)6] (en=ethylenediamine)

Two new heterometallic complexes, [Cu(en)(H₂O)]₂[Fe(CN)₆]·4H₂O (1) and [Cu(en)₂][KFe(CN)₆] (2), have been isolated from the reactions of CuCl₂ and en with K₃[Fe(CN)₆] in different molar ratios. Both complexes have been characterized by X-ray analyses, IR spectra and elemental analyses. Complex 1 is a cyanide bridged bimetallic assembly, its crystal structure consists of a two-dimensional polymeric sheet with two different rings, one a four-membered square ring and another a 12-membered hexagonal ring. The Fe(II) ion of 1 has two terminal, two linear bridging and two 1,1 en-on bridging cyanide groups. In the crystal structure of 2, the neighboring [Fe(CN)₆]³⁻ units are bridged by the K⁺ and the [K[Fe(CN)₆]]²⁻ units forming a three-dimensional network structure. The [Cu(en)₂]²⁺ units fill in the holes of the network acting as counter cations and charge compensations. Variable temperature magnetic susceptibility studies of 1 indicate that the complex exhibits ferromagnetic interaction between the Cu(II) ions.     

Spectral properties and bio-activity of copper(II) clofibriates, part III: crystal structure of Cu(clofibriate)2(2-pyridylmethanol)2, Cu(clofibriate)2(4-pyridylmethanol)2(H2O) dihydrate, and Cu2(clofibriate)4(N,N-diethylnicotinamide)2

New copper(II) clofibriates (clof, {2-(4-chlorophenoxy)-2-methylpropionic or 2-(4-chlorophenoxy)isobutyric acid}) of composition Cu(clof)₂L₂ (where L=2-pyridylmethanol (2-pymeth) (1), N-methylnicotinamide (Menia) (4), N,N-diethylnicotinamide (Et₂nia) (5), isonicotinamide (isonia) (7) or methyl-3-pyridylcarbamate (mpc) (8)), [Cu(clof)₂(4-pymeth)₂(H₂O)] · 2H₂O (4-pymeth=4-pyridylmethanol) (2 · 2H₂O) and Cu(clof)₂L (where L=4-pymeth (3) or Et₂nia (6)) have been prepared and spectroscopically characterized. All the Cu(clof)₂L₂ compounds seem to possess distorted octahedral copper(II) stereochemistry with differing tetragonal distortions. An X-ray analysis of 1 was carried out and it featured a tetragonal-bipyramidal geometry around the copper(II) atom. X-ray analysis of 2 · 2H₂O featured a square-pyramidal geometry around copper(II) atom. Both the Cu(clof)₂L compounds seem to consist of a binuclear unit of tetracarboxylate type bridging. An X-ray analysis of 6 revealed typical binuclear paddle-wheel type structure, consisting of two copper(II) atoms in square-pyramidal geometry bridged by four carboxylate anions in the xy-plane. All complexes under study were characterized by EPR and electronic spectroscopy. The antimicrobial effects have been tested on various strains of bacteria, yeasts and filamentous fungi.     

Syntheses and crystal structures of cyano-bridged cluster-metal layered coordination polymers [Cu(dien)]3[W4Te4(CN)12] · 9H2O and [Ni(en)(NH3)]3[W4Se4(CN)12] · 7.5H2O

Two new tetrahedral tungsten cyanide cluster compounds, [Cu(dien)]₃[W₄Te₄(CN)₁₂] · 9H₂O (1) (dien=diethylenetriamine) and [Ni(en)(NH₃)]₃[W₄Se₄(CN)₁₂] · 7.5H₂O (2) (en=ethylenediamine), were synthesized by treating aqueous solutions of the saltlike cluster compound K₆[W₄Te₄(CN)₁₂] · 5H₂O/K₆[W₄Se₄(CN)₁₂] · 6H₂O with copper(II)/nickel(II) chloride in aqueous ammonia containing dien/en. The cyano-bridged layered coordination polymeric compounds were characterized by single-crystal X-ray diffraction analysis: monoclinic, space group P2₁ for 1; trigonal, space group for 2. Structures of 1 and 2 consist of infinite neutral layers of cluster components {W₄Te₄(CN)₁₂}/{W₄Se₄(CN)₁₂} connected, one another by {Cu(dien)} or {Ni(en)(NH₃)} fragments, respectively.     

Synthesis and structural characterization of trans-[Mo2(H2DMepyF)2(CH3CN)4](BF4)6 (HDMepyF=N,N-di(6-methyl-2-pyridyl)formamidine)

Reaction of Mo₂(O₂CCH₃)₂(DMepyF)₂ (HDMepyF=N,N^′-di(6-methyl-2-pyridyl)formamidine) with HBF₄ in CH₂Cl₂/CH₃CN afforded the complex trans-[Mo₂(H₂DMepyF)₂(CH₃CN)₄](BF₄)₆ (1), which crystallized in two forms, trans-[Mo₂(H₂DMepyF)₂(CH₃CN)₄](ax-CH₃CN)₂(BF ₄)₆ · 2CH₃CN (1a), and trans- [Mo₂(H₂DMepyF)₂(CH₃CN)₄](ax-BF₄) ₂(BF₄)₄ · 2CH₃CN (1b). The molecular structures of complexes (1) consist of two quadruply bonded molybdenum atoms, which are spanned by two trans-bridging formamidinate ligands and coordinated by four trans-CH₃CN. Each H₂DMepyF⁺ ligand adopts an s-cis,s-cis- conformation. The difference between 1a and 1b is that complex 1a contains two CH₃CN molecules as axial ligands, while 1b contains two BF₄⁻ anions as axial ligands. Complex 1 is the first dimolybdenum complex containing a pair of trans bridging ligands and two pairs of trans-CH₃CN ligands.     

Synthesis and structure of two polymeric barium-oxydiacetates: [Ba(oda) · H2O]n and [Ba(Hoda)2]n (H2oda: oxydiacetic acid)

The reaction of barium carbonate or hydroxide with oxydiacetic acid leads to the self-assembly of two barium oxydiacetate polymers in good yield: [Ba(oda) · H₂O]_n (1) and [Ba(Hoda)₂]_n (2). The products have been characterized by elemental analysis, IR, TGA and single crystal X-ray diffraction studies. The central barium atom in each mononuclear fragment is nine-coordinate in 1 and 10-coordinate in 2. These fragments are bridged by carboxylato groups in anti-anti conformation and through H-bonds bonding interactions forming complex 3D networks.     

Selective synthesis of triangular cluster oxido-sulfidocomplexes of Mo and W: High yield preparations of [Mo3O2S2(H2O)9], [W3O2S2(H2O)9], [W2MoO2S2(H2O)9] and their derivatization

Reaction of [Mo₂O₂(μ-S)₂(H₂O)₆]²⁺ with Mo(CO)₆ or metallic Mo under hydrothermal conditions (140 °C, 4 M HCl) gives oxido-sulfido cluster aqua complex [Mo₃(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (1). Similarly, [W₃(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (2) is obtained from [W₂O₂(μ-S)₂(H₂O)₆]²⁺ and W(CO)₆. While reaction of [Mo₂O₂(μ-S)₂(H₂O)₆]²⁺ with W(CO)₆ mainly proceeds as simple reduction to give 1, [W₂O₂(μ-S)₂(H₂O)₆]²⁺ with Mo(CO)₆ produces new mixed-metal cluster [W₂Mo(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (3) as main product. From solutions of 1 in HCl supramolecular adduct with cucurbit[6]uril (CB[6]) {[Mo₃O₂S₂(H₂O)₆Cl₃]₂CB[6]}Cl₂⋅18H₂O (4) was isolated and structurally characterized. The aqua complexes were converted into acetylacetonates [M₃O₂S₂(acac)₃(py)₃]PF₆ (M₃ = Mo₃, W₃, W₂Mo; 5a-c), which were characterized by X-ray single crystal analysis, electrospray ionization mass spectrometry and ¹H NMR spectroscopy. Crystal structure of (H₅O₂)(Me₄N)₄[W₃(μ₃-S)(μ₂-S)(μ₂-O)₂(NCS)₉] (6), obtained from 2, is also reported.     

Robust anionic building blocks [M(malonate)2(H2O)2] for crystal engineering of inorganic-organic hybrid materials

One-pot reactions of transition metal (Cu^II, Ni^II, Co^II, or Cd^II) salt with malonic acid (H₂mal) in the presence of mesocyclic diamine generate three supramolecular complexes and a coordination polymer. [Cu(mal)₂(H₂O)₂](H₂O)₂(H₂DACH) (1) and [M(mal)₂(H₂O)₂](H₂DACO) (M = Ni for 2, and Co for 3) are ion-pair products and managed by charge-assistant noncovalent interactions (DACO = 1,5-diazacyclooctane, and DACH = 1,4-diazacycloheptane). In these structures, the similar mononuclear [M(mal)₂(H₂O)₂]²⁻ building blocks are connected by hydrogen bonds to form 2D networks (with the aid of one lattice water in the case of 1), which are further extended by the cationic diamine components to yield 3D pillar-layered solids. While [Cd(mal)(H₂O)₂]_n (4) is a neutral polymeric complex, in which the similar [Cd(mal)₂(H₂O)₂]²⁻ subunits are propagated by additional Cd-O coordinative forces to result in the final 2D layer.     

Synthesis, characterization and 1D helical chain crystal structure of [Cu(DBA)2(1,10-phen)]n and [Cd(DBA)2(1,10-phen)2] (DBA = benzilic acid)

Two novel complexes [Cu(DBA)₂(1,10-phen)]_n (1) and [Cd(DBA)₂(1,10-phen)₂] (2) [HDBA = benzilic acid: (C₆H₅)₂C(OH)COOH] have been synthesized and characterized by element analysis and fluorescence spectroscopy. The crystal structures of compounds 1, 2 and HDBA (3) were also determined. Complex 1 is a one-dimensional (1D) helical infinite chain, in which [(1,10)-phen]Cu^(II) units were bridged by benzilic acid. Complex 2 is a mononuclear structure, and is self-assembled through π-π stacking interactions to form a 1D helical chain. Compound 3 is self-assembled to form a 1D helical chain through hydrogen bonds interactions. Thermal analyses indicate that complexes 1 and 2 are stable under 200 and 254 °C in solid state, respectively.     

Cyano-bridged cluster-metal coordination compound: synthesis and crystal structure of [Cu(NH3)3][Cu(NH3)4][Cu(NH3)5][W4Te4(CN)12]·5H2O

Dark-brown single crystals of the title compound 1 were obtained in high yield by layering a CuCl₂ solution in 25% aqueous ammonia on a glycerol solution of K₆[W₄Te₄(CN)₁₂]·5H₂O. The complex 1 was characterized by single crystal X-ray diffraction analysis and IR spectroscopy. The X-ray structure of 1 reveals a polymeric chain cyano-bridged cluster-metal coordination compound. The [W₄Te₄(CN)₁₂]⁶⁻ cluster anions are linked one to another by Cu²⁺ cations through coordination by nitrogen atoms of the CN groups.     

Syntheses, structures and properties of copper(II) and cobalt(II) metal-organic frameworks based on R-isophthalate (R = -CH3 or -C(CH3)3) and 1,1′-(1,4-butanediyl)bis(imidazole) ligands

Three new complexes [Cu₂(mip)₂(bbi)]_n (1), {[Cu₂(tbip)₂(bbi)₂(H₂O)]·2H₂O}_n (2) and {[Co₂(tbip)₂(bbi)₂]·2H₂O}_n (3), were prepared through hydrothermal reactions of Cu(II) and Co(II) acetate with H₂mip or H₂tbip (H₂mip = 5-methyl isophthalic acid and H₂tbip = 5-tert-butyl isophthalic acid) and the flexible ligand bbi (bbi = 1,1′-(1,4-butanediyl)bis(imidazole)). All these complexes were structurally characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. Complex 1 exhibits a 3D network, which are constructed from 2D carboxylate layer and bbi pillar. Complex 2 possesses a 2D layer structure, and exists extensive hydrogen-bonding interactions, while complex 3 is constructed from 2D layers which consists of alternating left- and right-handed helical chains, and further assembled to form a 3D framework by hydrogen-bonding interactions. The thermal stabilities of the corresponding complexes have been briefly investigated. In addition, dominant antiferromagnetic coupling was observed in complex 1.     

A trinuclear copper(II) complex with 2,5-pyridine-dicarboxylato bridges - [Cu3(2,5-pydc)2(Me5dien)2(H2O)2(BF4)2] · H2O: Synthesis, crystal structure and magnetic properties

A trinuclear copper(II) complex, [Cu₃(2,5-pydc)₂(Me₅dien)₂(BF₄)₂(H₂O)₂] · H₂O 1, has been constructed from 2,5-pyridine-dicarboxylato bridges (2,5-pydc²⁻) and N,N,N′,N″,N″-pentamethyl-diethylenetriamine (Me₅dien) acting as a blocking ligand. The copper ions, within the centrosymmetric trinuclear cations, are connected by two 2,5-pydc²⁻ bridges, with an intramolecular Cu···Cu separation of 8.432 Å. The central copper ion exhibits an elongated octahedral geometry, with semicoordinated ions, while the terminal ones are pentacoordinated (distorted square-pyramidal geometry). The cryomagnetic investigation of 1 reveals an antiferromagnetic coupling of the copper(II) ions (J = −5.9 cm⁻¹, H = −JS_Cu1S_Cu2 − JS_Cu2S_Cu1a).     

Conformational flexibility of 2,6-bis(pyrazol-1-ylmethyl)pyridine (L) in [(L)Co(H2O)3]Cl2 and [(L)Ni(H2O)2Cl]Cl·H2O. Molecular structures and non-covalent interactions

Using a non-planar tridentate ligand 2,6-bis(pyrazol-1-ylmethyl)pyridine (L⁵) two new coordination complexes [(L⁵)Co^II(H₂O)₃]Cl₂ (1) and [(L⁵)Ni^II(H₂O)₂Cl]Cl·H₂O (2) have been synthesized and structurally characterized. Complex 1 has N₃O₃ distorted octahedral environment around Co^II with coordination by L⁵ (two pyrazole and a pyridine nitrogen in a facial mode) and three water molecules. Complex 2 has N₃O₂Cl distorted octahedral geometry around Ni^II with meridional L⁵ coordination, two water molecules, and a Cl⁻ ion. Analysis of the crystal packing diagram reveals the involvement of solvent (water as metal-coordinated and as solvent of crystallization) and counteranion (Cl⁻) to play significant roles in generating 1D chains, involving O-H···Cl, and O-H···O interactions.     

Cobalt(II) and nickel(II) coordination polymers constructed from P,P′-diphenylmethylenediphosphinic acid (H2pcp) and 4,4′-bipyridine (bipy): Structural isomerism in [Co(pcp)(bipy)0.5(H2O)2]

The P,P′diphenylmethylenediphosphinic acid (H₂pcp) reacts with Co(ClO₄)₂ · 6H₂O and 4,4′-bipyridine to give a mixture of two polymeric isomers of formula [Co(pcp)(bipy)_0.5(H₂O)₂], {red (1) and pink (2)} and the new violet hybrid [Co(Hpcp)₂] (3). The pure red and violet species have been obtained by the reaction of H₂pcp with Co(CH₃COO)₂ · 4H₂O and bipy or with Co(ClO₄)₂ · 6H₂O, respectively. The analogous reaction of Ni(CH₃COO)₂ · 4H₂O or Ni(ClO₄)₂ · 6H₂O with H₂pcp and bipy affords only the [Ni(pcp)(bipy)_0.5(H₂O)₂] species (4). The two cobalt isomers present different structural arrangements. Whereas the red isomer (1) shows an undulated 2D layered structure, the pink one (2) forms an infinite monodimensional strand. Both the architectures extend to higher dimensions through hydrogen bonding interactions. The nickel derivative is isomorphous with the red cobalt isomer. The violet [Co(Hpcp)₂] (3), which is isomorphous with the complexes of the reported series [M(Hpcp)₂], M = Ca(II), Mg(II), presents a monodimensional polymeric structure. Compounds 1 and 4 show a very similar thermal behaviour, the two water molecules being lost in the temperature range 25-150 and 160-320 °C, respectively. Temperature dependent X-ray powder diffractometry (TDXD) has been performed on compound 1 in order to follow the structural transformations that occur during the heating process.     

[Mn2(Fpymo)4(H2O)4]: Synthesis, structure, magnetism and thermally induced solid-to-solid polymerisation reactions

The reaction of an aqueous solution of Mn(ClO₄)₂ · 6H₂O with 5-fluoro-2-hydroxypyrimidine (HFpymo) and NaOH in 1:2:1 ratio affords a species analysing as Mn(Fpymo)₂(H₂O)₂ (1) in 70% yield. Single crystal X-ray analysis reveals that 1 consists of [Mn₂(μ-Fpymo-N¹,O²)₂(Fpymo-O²)₂(H₂O)₄] dinuclear units, in which each Mn(II) ion shows a slightly distorted trigonal bipyramidal stereochemistry. Thermal treatment of 1 above 150 °C gives an anhydrous, amorphous material analysing as Mn(Fpymo)₂ (2a). Further heating of this compound above 250 °C results in the formation of the microcrystalline Mn(Fpymo)₂ species (2b). The thermal dependence of the magnetic susceptibility χ has been studied for species 1 and 2b in the 2-300 K temperature range at 100, 300 and 5000 Oe field strengths. The fitting of the χ values of 1 to the Curie-Weiss equation gives values of C = 2.450(2) and θ = 1.0(2) K, which is indicative of an almost negligible magnetic interaction between the Mn(II) centres. At variance, 2b shows a significant antiferromagnetic behaviour, with a decrease of the μ_eff values upon cooling. The fitting of the χ values of 2b to the Curie-Weiss equation gives the respective C and θ values of 4.26(1) and −14.8(3) K, which agrees with an efficient coupling of the magnetic Mn(II) centres, possibly through bridges of the Fpymo-N¹,N³ kind, within a polymeric network. The N₂ and CO₂ gas adsorption measurements at 77 K and 293 K, respectively, show that the 2b phase is not microporous, which is reflected in its low BET surface (19 m² g⁻¹) and its BJH pore size distribution.     

Supramolecular assemblies of [Mo3Se4Clx(H2O)9−x] with cucurbituril; complementarity control through the variation of x

From solutions of seleno bridged triangular cluster Mo₃Se₄(aq)⁴⁺ in HCl, crystalline adducts with cucurbituril (Cuc, C₃₆H₃₆N₂₄O₁₂) of different composition, depending on HCl concentration, were isolated. From 2 M HCl, a monosubstituted cationic cluster crystallizes as {[Mo₃Se₄Cl(H₂O)₈]₂(C₃₆H₃₆N₂₄O₁₂)}Cl₆·16H₂O (1). Increase in HCl concentration to 6 M gives a pentasubstituted anionic species, (H₃O)₂[Mo₃Se₄Cl₅(H₂O)₄]₂(C₃₆H₃₆N₂₄O₁₂)·15H₂O (2). The crystal structures of 1 and 2 were determined by X-ray crystallography. Each portal of Cuc in 1 is covered with cluster cations [Mo₃Se₄Cl(H₂O)₈]³⁺ like a ‘lid’ on a ‘barrel’. Six water molecules in the trans position to the core μ₂-Se form complementary hydrogen bonds with oxygen atoms of Cuc (O?O, 2.713-3.067 Å). In 2 the complementarity is lost and the main structure building factor is short Se?Se interactions (Se?Se, 2.96-3.43 Å) between two adjacent anionic clusters. Stereochemistry of halide substitution in the triangular clusters M₃Q₄ is analyzed.     

Analysis of the main structural trends for biscyclometalated dinuclear rhodium compounds of general formula Rh2(O2CR)2(PC)2 · 2H2O

A new series of biscyclometalated dinuclear rhodium (II) compounds with the general formula Rh₂(O₂CR)₂(PC)₂ · 2H₂O, being PC = (C₆H₄)P(C₆H₅)₂, R = CH₃ (1 · 2H₂O), PC = [(p-CH₃ OC₆H₃)P(p-CH₃ OC₆H₄)₂], R = CF₃ (2 · 2H₂O), PC = (C₆H₄)P[CH(CH₃)₂]₂, R = CH₃ (3 · 2H₂O) and PC = (C₆H₄)P(C₆H₅)₂, R = C₆F₅ (4 · 2H₂O) has been obtained. The crystal structures for these compounds have been determined by X-ray diffraction and the main structural trends, bond lengths, bond angles and torsion angles have been analyzed, and have also been compared with the structural parameters for different analogous complexes described previously in the literature.     

Structural analysis and magnetic properties of the copper(II) dicyanamide complexes [Cu2(dmphen)2(dca)4], [Cu(dmphen)(dca)(NO3)]n and [Cu(4,4-dmbpy)(H2O)(dca)2] (dca=dicyanamide; dmphen=2,9-dimethyl-1,10-phenanthroline; 4,4-dmbpy=4,4-dimethyl-2,2-bipyridine)

The preparation, crystal structures and magnetic properties of three copper(II) compounds of formulae [Cu₂(dmphen)₂(dca)₄] (1), [Cu(dmphen)(dca)(NO₃)]_n (2) and [Cu(4,4^′-dmbpy)(H₂O)(dca)₂] (3) (dmphen=2,9-dimethyl-1,10-phenanthroline, dca=dicyanamide and 4,4^′-dmbpy=4,4^′-dimethyl-2,2^′-bipyridine) are reported. The structure of 1 consists of discrete copper(II) dinuclear units with double end-to-end dca bridges whereas that of 2 is made up of neutral uniform copper(II) chains with a single symmetrical end-to-end dca bridge. Each copper atom in 1 and 2 is in a distorted square pyramidal environment: two (1) or one (2) nitrile-nitrogen atoms from bridging dca groups, one of the nitrogen atoms of the dmphen molecule (1 and 2) and either one nitrile-nitrogen from a terminal dca ligand (1) or a nitrate-oxygen atom (2) build the equatorial plane whereas the second nitrogen atom of the heterocyclic dmphen fills the axial position (1 and 2). The copper-copper separations through double (1) and single (2) end-to-end dca bridges are 7.1337(7) (1) and 7.6617(7) (2). Compound 3 is a mononuclear copper(II) complex whose structure contains two neutral and crystallographically independent [Cu(4,4^′-dmbpy)(H₂O)(dca)₂] molecules which are packed in two different layer arrangements running parallel to the bc-plane and alternating along the a-axis. The copper atoms in both molecules have slightly distorted square pyramidal surroundings with the two nitrogen atoms of the 4,4^′-dmbpy ligand and two dca nitrile-nitrogen atoms in the basal plane and a water oxygen in the apical position. A semi co-ordinated dca nitrile-nitrogen from a neighbour unit [2.952(6) Å for Cu(2)-N] is in trans position to the apical water molecule in one of the two molecules, this feature representing part of the difference in supramolecular connections in the alternating layers referred to above. Magnetic susceptibility measurements for 1-3 in the temperature range 1.9-290 K reveal the occurrence of weak antiferromagnetic interactions through double [J=−3.3 cm⁻¹ (1), ] and single [J=−0.57 cm⁻¹ (2), ] dca bridges and across intermolecular contacts [θ=−0.07 K (3)].     

Two new supermolecular structures of organic-inorganic hybrid compounds: [Zn(phen)(SO4)(H2O)2]n and [Cu(phen)(H2O)2] · SO4 (phen = 1,10-phenanthroline)

Two new organic-inorganic hybrid compounds [Zn(phen)(SO₄)(H₂O)₂]_n (1) and [Cu(phen)(H₂O)₂] · SO₄ (2) have been prepared by conventional aqueous solution synthesis and characterized by single-crystal X-ray diffraction, IR spectroscopy, thermal gravimetric analysis (TGA) and fluorescent spectroscopy. In compound 1, the sulfate group adopts bidentate mode to coordinate with two Zn(II) ions to form one-dimensional polymer. The one-dimensional polymers are further linked together via the intermolecular hydrogen-bonding and π-π stacking interactions to form a 3D supramolecular framework. Compound 2 is build up of discrete [Cu(phen)(H₂O]²⁺ cations and SO₄²⁻ anions to form a three-dimensional framework via hydrogen-bonding and π-π stacking interactions. Furthermore, the luminescent properties of both 1 and 2 were studied. The complexes 1 and 2 excited at 280 nm wavelength produced characteristic luminescence features, arising maybe due to the π-π transitions.