Three Ag(I)–cyanide coordination polymers with metal bonds tuned by N-heterocyclic ligands

Hydrothermal reactions of AgNO₃, K₃[Fe(CN)₆] with N-heterocyclic ligands afforded three novel Ag(I)–cyanide coordination polymers, [Ag₂(CN)₂(tpt)]_n (1), {[Ag(CN)(bpe)_0.5][Ag(CN)]}_n (2) and [Ag(CN)(btmb)_0.5]_n (3) (tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine, bpe = 1,2-bis(4-pyridyl)ethane, btmb = 1,2-bis(1,2,4-triazol-1-ylmethyl)benzene). In complex 1, two Ag(CN) linear chains are bridged by bidentate tpt ligand to form a ladder-like structure, which are further connected by AgAg metal bond to generate a 2D polymeric network. Complex 2 is an interesting 3D supramolecular architecture assembled by 2D [Ag¹(CN)(bpe)_0.5]_n network and linear [Ag²(CN)]_n chain combined by strong AgAg metal bond. Complex 3 is a 1D ladder-like double-chain polymer constructed from Ag–cyanide linear chains and btmb spacer, which is further extended to a 2D supramolecular network by Ag–Ag weak interaction. The Ag–Ag metal interactions play important roles in the construction of three coordination polymers. Complexes 1 and 2 are respectively thermally stable at 300 and 180 °C. Complexes 1 and 3 emit strong blue luminescence.     

Self-assembly of a novel 3D copper(I)-tetrazolate supramolecular framework via interpenetration of porous 2D double-layer motifs

The self-assembly of CuCN and 1H-TAZ ligand under hydrothermal conditions generated a novel three-dimensional hybrid supramolecular framework, namely, [Cu₆(TAZ)₄(CN)₂]_n (1) (TAZ = tetrazole). Single-crystal X-ray diffraction show that [Cu₂(TAZ)₂] binuclear subunits are linked by μ₂- and μ₃-CN groups to give a 2D double-wave-shaped network, which possesses 1D channels with four open-windows. The 2D bilayers interpenetrated each other to form the 3D supramolecular framework of 1.     

Synthesis,crystal, luminescent properties and electronic structures of two copper(I) halide polymers based on Cu4I4 cubane tetramers

Two novel coordination polymers [Cu₄I₄(en)₂]_n 1 and [Cu₄I₄(pn)₂]_n 2 (en = 1,2-diaminoethane and pn = 1,3-diaminopropane) were prepared by hydrothermal methods and determined by single-crystal X-ray diffraction analysis. Compound 1 possesses a 3D zeolite-like architecture with infinite intersected channels, constructing from cubane Cu₄I₄ tetramers, which is simplified into a twofold interpenetrating dia network. Compound 2 with the similar Cu₄I₄ cores, features a 2D layer with parallelogram-shaped channels along the b axis, showing a uninodal sql net. Both exhibit luminescent emission bands at about 600 nm at room temperature when excited at 350 and 370 nm, respectively. Furthermore, thermogravimetric analyses, optical diffuse reflectance spectroscopy, and the theoretical calculations were discussed.     

One-dimensional copper(II) complex containing alternate single and double end-on azide ligands: Crystal structure and magnetic characterization

A novel one-dimensional azido-bridged coordination polymer of formula [Cu₂(L)₂(H₂O)(N₃)₄]_n (1) has been synthesized and characterized crystallographically and magnetically, where L is 5-methylpyrimidin-2-amine. Complex 1 consists of 1D chain in which the Cu(II) ions with a square pyramidal geometry are alternately bridged by asymmetric single and symmetric double end-on (EO) azido ligands. Magnetic analysis reveals that the dominating ferromagnetic interaction is mediated by the symmetric double azido bridge with the exchange parameter J = 55.17 cm⁻¹.     

Influence of symmetric benzene–polycarboxylate acids on the structures of silver-aminopyrimidyl derivative system

Two novel coordination polymers, [Ag(BTC)_1/3(ADMP)]_n (1), [Ag(BDC)_1/2(ADMP)]_n (2) (2-amino-4,6-dimethylpyrimidine = ADMP; H₃BTC = 1,3,5-benzenetricarboxylic acid; H₂BDC = 1,4-benzenedicarboxylic acid), have been synthesized under the ammoniacal conditions and structurally characterized. In complex 1, H₃BTC ligand showing a new coordination mode links silver atoms to generate a two-dimensional (2-D) honeycomb-like structure, which is further linked through ADMP ligands to produce a complicated three-dimensional (3-D) framework. Complex 2 features a 2-D infinite layer framework consisting of binuclear silver clusters, which is further stacked via intermolecular C_methyl–H?π short contacts and Van der Waals interactions to form a 3-D supramolecular architecture.     

Dicyanamido–metal(II) complexes. Part 3: Hydrolysis of the dicyanamide into amidocyanamide during its interaction with Cu(II) perchlorate and 2-pyridylcarbonyl-N,N-bis(2-pyridylmethyl)amine

The reaction of Cu(ClO₄)₂, 2-pyridylcarbonyl-N,N-bis(2-pyridylmethyl)amine (DPA-CO-py) and sodium dicyanamide (Nadca) in aqueous medium led to the isolation of three complexes: {[Cu(DPA)(μ_1,5-dca)]ClO₄}_n (1), [Cu₂(pic)₂(μ_1,3-H₂NCO–N–CN)₂(H₂O)₂] · 2H₂O (2) and Cu(pic)₂ · H₂O (3). The Cu²⁺ ion, during its complex formation with DPA-CO-py and dca not only assisted the hydrolysis of DPA-CO-py to the corresponding di(2-methylpyridyl)amine (DPA) and picolinic acid (Hpic) but also resulted in partial hydrolysis of one of the two nitrile groups of the dicyanamide, NC–N–CN^? (dca) to amidocynamide, H₂NCO–NH–CN. The complexes were structurally characterized and the single X-ray structures for 1 and 2 reveal their identity. Complex 1 forms a 1D polymeric chain with the dca acting as a μ_1,5-bridging ligand via the terminal nitrile nitrogen atoms. A distorted SP geometry around the Cu²⁺ centers was achieved by the three N-atoms of the DPA and by the two nitrile groups of the bridging dca ligands. Complex 2 consists of a dimeric unit with CuN₃O₂ chromophore in coordination polyhedron that has a distorted SP geometry. The amidocyanamide ion, H₂NCO–N–CN^? acts as bis(monodentate) μ_1,3-bridging ligand via the central amido and terminal nitrile nitrogen atoms whereas the picolinate anion forms a six-membered chelate ring through its pyridyl nitrogen and an oxygen atom of the carboxylate group, and the aqua water occupies the apical position of the structure. Complex 1 exhibits very weak antiferromagnetic coupling (J = ?0.31 cm^?1) whereas 2 shows a significant antiferromagnetic interaction between the two copper centers (J = ?13.6 cm^?1).     

Synthesis,crystal structure and magnetic properties of a new cyanide-bridged mixed-valence copper(I)/copper(II) clathrate

A unique cyanide-bridge mixed-valence Cu^I/Cu^II clathrate of formula [Cu^I₂(CN)₃][{Cu^II(tren)}₂(μ-CN)](CF₃SO₃)₂ [tren = tris(2-aminoethyl)amine] containing cyanide-bridged [{Cu^II(tren)}₂(μ-CN)]^3 + binuclear cations stacked between anionic honeycomb layered copper(I) cyanide networks, was synthesized and structurally characterized by single crystal X-ray diffraction. Variable-temperature magnetic susceptibility studies showed that the cyanide bridge mediates a strong antiferromagnetic interaction between the copper(II) centers (J = − 160 cm^− 1, the spin Hamiltonian being defined as H = −J S_A⋅S_B).     

Role of spacers and substituents in the self-assembly process: Syntheses and characterization of two novel thiocyanatocuprates polymers

Two novel cation-induced complexes, {(Phen-dq) [Cu₂(SCN)₄]}_n (1) and {(Phen-dzp) [Cu₂(SCN)₄]}_n (2) [Phen-dq = (C₁₄H₁₂N₂)²⁺, 5,6-dihydropyrazino[1, 2, 3, 4-lmn]-1, 10-phenanthrolinium, Phen-dzp = (C₁₅H₁₄N₂)²⁺, 6,7-dihydro-5H-[1, 4]diazepino[1, 2, 3, 4-lmn][1,10]phenanthroline-4, 8-diium], have been synthesized via the self-assembly reaction in solution. The compound 1 possesses a two-dimensional supramolecular network linked by bridging thiocyanate groups. Complex 2 is also a two-dimensional polymeric architecture with the organic cation Phen-dzp trapped in it. Each Cu(I) atom is coordinated by two N atoms and two S atoms from four NCS groups to form a Cu₂(NCS)₂ rectangular dimer unit. In these two compounds, thanks to the difference from organic cations, the simple modification from Phen-dq to Phen-dzp leads to distinct structures between 1 and 2, and these “planar” cations are effective guests to manipulate the aggregate structure of thiocyanatocuprates.     

Syntheses,structures and photoluminescence of Ln(III)–Cu(I) coordination polymers based on benzimidazole-5-carboxylate and oxalate ligands

Three novel Ln(III)–Cu(I) coordination polymers, namely [LnCu(Hbic)₃(ox)_0.5] [Ln = Sm (1), Dy (2), Hbic = benzimidazole-5-carboxylate, ox = oxalate] and [EuCu(Hbic)₂(ox)H₂O]·2H₂O (3) have been hydrothermally synthesized and stucturally characterized. Both complexes 1 and 2 display the same unusual 2D layer heterometallic coordination frameworks that are built up by dimeric [Ln₂(Hbic)₆] cores and oxalate ligands by sharing Cu(I) ions. Complex 3 represents 1D polymeric chain architecture constructed from Eu₂Cu₂ ring units and oxalate ligands. Furthermore, the luminescent property of complex 3 has also been investigated.     

Hydrothermal syntheses and characterization of a series of mixed-ligand luminescent CdII frameworks with novel 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl) acetate ligand and benzenedicarboxylate isomers

Under similar hydrothermal synthetic conditions using a novel flexible ligand 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetonitrile (PPAN), benzenedicarboxylate isomers (H₂pa = phthalate, H₂ip = isophthalate, and H₂tp = terephthalate) and Cadmium(II) acetate, three novel mixed-ligand Cd(II) coordination polymers {[Cd₂(PPAA)₂(μ-pa)(H₂O)]·2H₂O}_n (1), {[Cd₄(PPAA)₄ (μ₄-ip)₂]·2H₂O}_n (2) and {[Cd₂(PPAA)₂(μ-tp)]·2H₂O}_n (3) (PPAA⁻ = 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl) acetate) have been isolated, in 1–3 PPAN, and are also hydrolyzed into a novel PPAA⁻ ligand. Complex 1 is a 1D coordination polymer in which the tetra-nuclear [Cd₄(PPAA)₄]^4 + structural units are extended by tri-dentate μ-pa^2 − ligands. Complex 2 contains binuclear [Cd₂(PPAA)₂]^4 + structural units, which are extended by four tetra-dentate μ₄-ip^2 − ligands to link eight neighboring binuclear [Cd₂(PPAA)₂]^4 + units ultimately forming a 2D layered framework, while complex 3 contains 1D double chain containing [Cd(PPAA)]_n cation structural units, which are further extended by tetradentate μ-tp^2 − ligands to form a new 2D layered framework. All the complexes have been investigated by elemental analysis, FT-IR, thermal analysis and fluorescence characterization. The flexible coordination modes of PPAA⁻ are also briefly analyzed. The flexible coordination modes of PPAA⁻ and benzenedicarboxylate isomers also reveal great potential in the construction of these novel mixed-ligand luminescent frameworks with diverse structural motifs and unique functional properties.     

Two Mn(II)–Au(I) supramolecular assemblies bonded by coordination,aurophilicity and hydrogen-bonding, π–π interactions and their magnetic properties

Two Mn(II)–Au(I) supramolecular assemblies {{Mn[Au(CN)₂]₂(H₂O)₄} [Au(CN)₂]₂(H₂bpy) · H₂O}(bpy = 4,4′-bipyridine) 1 and {Mn(4,4′-dmbpy) [Au(CN)₂]₂(CH₃OH)} (4,4′-dmbpy = 4,4′-dimethyl-bipyridine) 2 have been synthesized and magnetic properties have been investigated The interplay of aurophilicity, coordination, hydrogen-bonding and π–π interactions in two complexes result in three-dimensional network.     

New μ-oxo-bridged tetranuclear Cu(II) complex with Schiff-base ligand: Synthesis,crystal structure and magnetic properties

A new μ-oxo-bridged Cu(II) complex with cubane-like tetranuclear copper(II) complex, [Cu₄(L¹)₄] · 4H₂O (1) (H₂L¹ = 2-(3-methoxy-salicylidene-amino)-benzyl-alcohol), has been prepared, and structurally characterized by X-ray crystallography. Complex 1 crystallized in the monoclinic space group P₂₁/n and has a tetranuclear core of Cu₄O₄. The temperature dependence of magnetic susceptibility measurements shown that complex 1 exhibits a strong antiferromagnetic interaction with J = −103.4 cm⁻¹.     

A two-dimensional copper polymer constructed from rod-shaped ferromagnetic secondary building units

On the basis of rod-shaped secondary building units (SBUs), a novel two-dimensional (2D) azide–copper polymer, [Cu₃(N₃)₄(anol)₂]_∞ (1; anol = aminoethanol), was synthesized and structurally characterized. Complex 1 is a neutral 2D coordination network consisting of trinuclear copper(II) clusters [Cu₃(N₃)₄(anol)₂] connected with the bridge of end-end (EE) azide group. Magnetic data analysis shows that a metamagnetic behavior is observed for 1 which is associated with significant ferromagnetic coupling intracluster over 4 K.     

A 2D brickwall architecture from a double-T-shaped ligand and hybrid coordinatively unsaturated copper: Synthesis,structure, and framework dynamic

A double-T-shaped ligand (H₄BPTC) as the spacer has been first used to direct the assembly of a 2D coordination polymer with brickwall network topology, [Cu₂(BPTC)(Im)₄(H₂O)(DMF)]_n (1) (DMF = N,N-dimethylformamide, H₄BPTC = Biphenyl-3,3′,4,4′-tetracarboxylic acid, Im = imidazole), which exhibits an interesting framework dynamic upon de-/resolvation.     

Cyanide-bridged mixed-valence copper(II/I) coordination polymers: Unique 7-connected sev-type 3D network versus anionic 2D host network encapsulated with cationic complex

Reactions of CuCl₂, K₂[Ni(CN)₄]/K₃[Co(CN)₆], and 5-amino-1H-tetrazole led to cyanide-bridged mixed-valence Cu(II/I) complexes, [Cu(H₂O)₃Cu₃(CN)₅] (1) and [Cu(H₂O)₄][Cu₄(CN)₆] (2).The uncommon semi-closed {Cu₂(CN)₃} dimmers in 1 are bridged by μ₃-C,C,N cyanide ligands to afford rare 1D centipedal-like chain motifs, which are further bridged by μ₂-C,N and metalloligand “CN–Cu(4)–CN” to finish sophisticated zeolite-like 3-D structure. Topologically, 1 is the first example of uninodal 7-connected sev-like cyanide-bridged network. Compound 2 consists of two-dimensional honeycomb-related anionic layers [Cu₄(CN)₆]^2 −, within which the [Cu(H₂O)₄]^2 + cations are intercalated into alternate interlamellar space. Compound 1 shows antiferromagnetic couple arising from pure ground-state configuration of Cu(II) mediated by diamagnetic bridges –CN–Cu^I–CN −. The inclusion compound 2 shows blue photoluminescence originated from Cu(I) center to the unoccupied π* orbital of the cyanide ligand (MLCT) charge transfer.     

Magnetic properties and structure of a new one-dimensional azido-bridged nickel(II) coordination polymer

A new one-dimensional nickel(II) coordination polymer with azido-bridge, [Ni(dpa)(N₃)₂] · H₂O 1 (where dpa is the 2,2′-dipyridylamine ligand) has been synthesized and crystal structure was determined by single-crystal X-ray diffraction. Complex 1 exhibits a zig-zag chain structural arrangement, and the hexa-coordinated Ni(II) ion exhibits a distorted octahedral coordination sphere. The chains topologies are built via three EO and one EE azido bridges. The study of the magnetic properties reveals dominating antiferromagnetic interactions between Ni(II) ions through the EE bridges.     

A 3D Cu(II) coordination polymer constructed from BIBP (BIBP = 5,5′-bis(1H-imidazol-1-yl)-2,2′-bithiophene) ligand with semiconductive property

Hydrothermal reaction of Cu(NO₃)₂·3H₂O with BIBP and H₂hfipbb at 105 °C yielded a novel 3D Cu(II) coordination polymer, {[Cu₂(BIBP)_0.5(hfipbb)₂(CH₃CN)]·5H₂O}_n (1) [BIBP = 5,5′-bis(1H-imidazol-1-yl)-2,2′-bithiophene, H₂hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid)]. Compound 1 displays a 3D 2-fold interpenetrating framework with {4⁴.6⁶} sqp topology, containing interesting ⋯LRLR⋯ double helical chains. The compound 1 was characterized by IR spectra, elemental analysis, thermal analysis and single crystal X-ray diffraction. In addition, solid-state UV–vis spectra experiment shows that compound 1 exhibits semiconductive property with a band gap of 2.46 eV.     

Syntheses,structures and photocatalytic properties of two coordination polymers based on bis(1,2,4-triazol-4-ylmethyl)benzene and multicarboxylates

Two coordination polymers {[Cu₄(OH)₂(btrb)₂(btc)₂]·4H₂O}_n (1) and {[Cd₂(btrb)(adc)₂(H₂O)]·H₂O}_n (2) were synthesized with hydrothermal method and characterized (btrb = 1,4-bis(1,2,4-triazol-4-ylmethyl)benzene, btc = 1,3,5-benzenetricarboxylate, adc = 1,3-adamantanedicarboxylate). 1 shows an unusual (3,10)-connected two-dimensional metal–organic framework based on the tetranuclear copper(II) cluster [Cu₄(μ₃-OH)₂]. 2 is an interesting three-dimensional network based on the one-dimensional metal–organic nanotube. 1 shows good photocatalytic activity for the degradation of methyl blue (MB). The luminescence of 2 was investigated.     

Six-, seven- and eight-coordinated Cd(II) ions with N-heterocyclic multicarboxylic acids

Two novel cadmium complexes [Cd₃(pta)₂(H₂O)₄]_n (1) (H₃pta = 2,4,6-pyridinetricarboxylic acid) and {[Cd(H₂pza)(H₂O)₂] · 2H₂O}_n (2) (H₄pza = 2,3,5,6-pyrazinetetracarboxylic acid) were synthesized. In both complexes, Cd(II) ions show three different coordination numbers of six and seven in 1 and eight in 2, respectively. Complex 1 displays a three-dimensional network structure and 2 shows a one-dimensional chain structure. The one-dimensional chains in 2 are vertical or parallel to each other and form a three-dimensional network structure by hydrogen bonds. In addition, 1 emits intense fluorescence on excitation of 342 nm.     

A copper coordination polymer based on bis(imidazole) and thiophenedicarboxylate for photocatalytic degradation of organic dyes under visible light irradiation

The copper(II) coordination polymer [Cu₂(bix)(sdc)₂]_n (1) was synthesized by the hydrothermal method (bix = 1,4-bis(2-methyl-imidazol-1-ylmethyl)benzene, sdc = 2,5-thiophenedicarboxylate). The copper(II) atom of 1 shows unsaturated square-pyramidal configuration. 1 exhibits the 2-fold interpenetrating three-dimensional pcu network based on the [Cu₂(COO)₄] dimers. 1 is an efficient and universal photocatalyst for the degradation of the organic dyes methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) under visible light irradiation, and is very stable and can be reused.