Azamacrocyclic-based metal organic frameworks: Design strategies and applications

Synthesis and crystal structure of trans-diaqua(1,4,8,11-tetraazaundecane)copper(II) isophthalate monohydrate

The complex cation of the title compound contains a tetra­gonally distorted trans-CuN₄O₂ octa­hedron. In the crystal, the components are linked by numerous N—H⋯O and O—H⋯O hydrogen bonds, forming electroneutral sheets oriented parallel to the ac plane, which are further consolidated into bilayers due to hydrogen-bonding with the participation of the water mol­ecule of crystallization.

In the title hydrated mol­ecular salt, [Cu(C₇H₂₀N₄)(H₂O)₂](C₈H₄O₄)·H₂O, the metal ion is coordinated by the two primary and two secondary N atoms of the amine ligand and the mutually trans O atoms of the water mol­ecules in a tetra­gonally distorted octa­hedral geometry. The average equatorial Cu—N bond lengths (2.013 and 2.026 Å for Cu—N_prim and Cu—N_sec, respectively) are substanti­ally shorter than the average axial Cu—O bond length (2.518 Å). The tetra­amine ligand adopts its energetically favored conformation with its five- and six-membered chelate rings in gauche and chair conformations, respectively. In the crystal, the N—H donor groups of the tetra­amine, the acceptor carboxyl­ate groups of the isophthalate dianion and both the coordinated water mol­ecules and the water mol­ecule of crystallization are involved in numerous N—H⋯O and O—H⋯O hydrogen bonds, resulting in the formation of electroneutral layers oriented parallel to the ac plane.

Synthesis and crystal structure of bis[trans-diaqua(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)nickel(II)] trans-(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)bis[4,4′,4′′-(1,3,5-trimethylbenzene-2,4,6-triyl)tris(hydrogen phenylphosphonato-κO)]nickel(II) decahydrate

The components of the title compound, [Ni(C10H24N4)(H2O)2]2[Ni(C10H24N4)(C27H24O9P3)2]·10H2O are two centrosymmetric [Ni(C10H24N4)(H2O)2]2+ dications, a centrosymmetric [Ni(C10H24N4)(C27H24O9P3)2]4− tetra-anion and five crystallographically unique water molecules of crystallization. All of the nickel ions are coordinated by the four secondary N atoms of the macrocyclic cyclam ligands, which adopt the most energetically stable trans-III conformation, and the mutually trans O atoms of either water molecules in the cations or the phosphonate groups in the anion in a tetragonally distorted NiN4O2 octahedral coordination geometry. Strong O—H...O hydrogen bonds between the protonated and the non-protonated phosphonate O atoms of neighboring anions result in the formation of layers oriented parallel to the bc plane, which are linked into a three-dimensional network by virtue of numerous N—H...O and O—H...O hydrogen bonds arising from the sec-NH groups of the macrocycles, phosphonate O atoms and coordinated and non-coordinated water molecules.

Fluorogenic Detection of Sulfite in Water by Using Copper(II) Azacyclam Complexes

Copper(II) azacyclam complexes (azacyclam = 1,3,5,8,12-pentaazacyclotetradecane) containing naphthyl or dansyl subunits can be prepared by template synthesis involving proper sulfonamide derivatives as locking fragments. The macrocyclic complexes are very poorly emissive due to the fluorescence-quenching behavior displayed by Cu²⁺ ions. However, the fluorescence can be recovered as a result of the decomposition of the complexes, which induces the release of free light-emitting subunits to the solution. This reaction takes place very slowly in neutral water but its rate is increased by the presence of sulfite. Therefore, [Cu(azacyclam)]²⁺ derivatives have been investigated as simple chemical probes for the fluorogenic detection of sulfite both on laboratory and real samples. Preliminary tests performed on samples of white wine provided sulfite concentration values that are in agreement with those obtained by a standard analytical method.

Plumbing the uncertainties of solvothermal synthesis involving uranyl ion carboxylate complexes

Uranyl ion complexes with long-chain, saturated or unsaturated aliphatic dicarboxylate ligands illustrate how solvo-hydrothermal synthetic conditions sometimes result in the formation of species different from those hoped for.

Chromogenic detection of xylene isomers and luminogenic chemosensing of o-xylene employing a new macrocyclic cobalt complex: synthesis, and X-ray crystallographic, spectroscopic and computational studies

A new binuclear Co(ii) complex, coordinating via two pyridine side-arms linked to two dinaphtho-diazacrown ether macrocyclic ligands, was synthesized and used as a colourimetric and fluorogenic sensor as well as an oxidation catalyst of xylene isomers at room temperature.

Crystal structure of [{[Ni(C10H24N4)][Ni(CN)4]}·2H2O] n , a one-dimensional coordination polymer formed from the [Ni(cyclam)]2+ cation and the [Ni(CN)4]2- anion

The title coordination polymer consists of parallel linear chains built up of macrocyclic cations possessing a slightly tetra­gonally distorted NiN₆ octa­hedral coordination geometry formed by four N atoms of the aza­macrocyclic ligand in the equatorial plane and two trans N atoms of the cyanide groups of the bridging tetra­cyano­nickelate anion in the axial positions. In the crystal, two independent [10] polymeric chains are cross-linked by N—H⋯O_w (w = water) and O_w—H⋯N_c (c = cyanide) hydrogen bonds into a three-dimensional network.

The asymmetric unit of the title compound, catena-poly[[[(1,4,8,11-tetra­aza­cyclo­tetra­decane-κ⁴N¹,N⁴,N⁸,N¹¹)nickel(II)]-μ-cyanido-κ²N:C-[bis­(cyanido-κC)nickel(II)]-μ-cyanido-κ²C:N] dihydrate], {[Ni₂(CN)₄(C₁₀H₂₄N₄)]·2H₂O]_n or [{[Ni(C₁₀H₂₄N₄)][Ni(CN)₄]}·2H₂O]_n, consists of a pair of crystallographically non-equivalent macrocyclic cations and anions. The nickel(II) ions (all with site symmetry ) are coordinated by the four secondary N atoms of the macrocyclic ligands, which adopt the most energetically stable trans-III conformation, and the mutually trans N atoms of the tetra­cyano­nickelate anion in a slightly tetra­gonally distorted NiN₆ octa­hedral coordination geometry. The [Ni(CN)₄)]^2– anion exhibits a bridging function, resulting in the formation of parallel polymeric chains running along the [10] direction. The water mol­ecules of crystallization play a pivotal role in the three-dimensional supra­molecular organization of the crystal. Acting as acceptors, they form N—H⋯O_w (w = water) hydrogen bonds with the secondary amino groups of the macrocycles, forming layers oriented parallel to the (001) plane. At the same time, as donors, they inter­act with the non-coordinated cyano groups of the anion via O_w—H⋯N_c (c = cyanide) hydrogen bonds, giving two-dimensional layers oriented parallel to the (100) plane and thus generating a three-dimensional network.

Crystal structure of trans-di-aqua-(1,4,8,11-tetra-aza-undeca-ne)nickel(II) bis-(pyridine-2,6-di-carboxyl-ato)nickel(II)

The coordination polyhedra of the nickel(II) ions of the title compound in the complex cation and the anion, viz., trans-NiN₄O₂ and trans-NiO₄N₂, are distorted octa­hedra. In the crystal, the donor groups of the tetra­amine and the coordinated water mol­ecules and the carboxyl­ate groups of the pyridine-2,6-di­carboxyl­ate anions are involved in numerous N—H⋯O and O—H⋯O hydrogen bonds, thereby forming sheets of ions lying parallel to the (001) plane.

The asymmetric unit of the title compound, trans-di­aqua­(1,4,8,11-tetra­aza­undecane-κ⁴N¹,N⁴,N⁸,N¹¹)nickel(II) bis­(pyridine-2,6-di­carboxyl­ato-κ³O²,N,O⁶)nickel(II) {[Ni(L)(H₂O)₂][Ni(pdc)₂] where L = 1,4,8,11-tetra­aza­undecane (C₇H₂₀N₄) and pdc = the dianion of pyridine-2,6-di­carb­oxy­lic acid (C₇H₃NO₄²⁻)} consists of an [Ni(L)(H₂O)₂]²⁺ complex cation and a [Ni(pdc)₂]^2– anion. The metal ion in the cation is coordinated by the four N atoms of the tetra­amine ligand and the mutually trans O atoms of the water mol­ecules in a tetra­gonally elongated octa­hedral geometry with the average equatorial Ni—N bond length slightly shorter than the average axial Ni—O bond [2.087 (4) versus 2.128 (4) Å]. The ligand L adopts its energetically favored conformation with five-membered and six-membered chelate rings in gauche and chair conformations, respectively. In the complex anion, the Ni^II ion is coordinated by the two tridentate pdc^2– ligands via their carboxyl­ate and nitro­gen atom donors in a distorted octa­hedral trans-NiO₄N₂ geometry with nearly orthogonal orientation of the planes defining the carboxyl­ate rings and the average Ni—N bond length [1.965 (4) Å] shorter than the average Ni—O bond distance [2.113 (7) Å]. In the crystal, the NH donor groups of the tetra­amine, the carb­oxy­lic groups of the pdc^2– anion and the coordinated water mol­ecules are involved in numerous N—H⋯O and O—H⋯O hydrogen bonds, leading to electroneutral sheets oriented parallel to the (001) plane.

Modulating the Acidic and Basic Site Concentration of Metal-Organic Framework Derivatives to Promote the Carbon Dioxide Epoxidation Reaction

Metal-organic framework (MOF) is an ideal precursor/template for porous carbon, and its active components are uniformly doped, which can be used in energy storage and catalytic conversion fields. Metal-organic framework PCN-224 with carboxylporphyrin as the ligand was synthesized, and then Zn²⁺ and Co²⁺ ions were coordinated in the center of the porphyrin ring by post-modification. Here, PCN-224-ZnCo with different ratios of bimetallic Zn²⁺ /Co²⁺ ions were used as the precursor, and the metal-nitrogen-carbon(M-N-C) material of PCN-224-ZnCo-950 was obtained by pyrolyzing the precursor at 950 °C in Ar. Because Zn is easy to volatilize at 950 °C, the formed M-N-C materials can reflect different Co contents and different basic site concentrations. The formed material still maintains the original basic framework. With the increase of Zn²⁺ /Co²⁺ ratio in precursor, the concentration of N-containing alkaline sites in pyrolysis products gradually increase. Compared with the precursor, PCN-224-ZnCo₁ -950 with Zn²⁺ /Co²⁺ =1 : 1 has greatly improved basicity and suitable acidic/ alkaline site concentration. It can be efficiently used to carbon dioxide absorption and catalyze the cycloaddition of CO₂ with epoxide. More importantly, the current method of adjusting the acidic/basic sites in M-N-C materials through volatilization of volatile metals can provide an effective strategy for adjusting the catalysis of MOF derivatives with porphyrin structure.

Flexible and porous 2D layered structures based on mixed-linker metal-organic frameworks for gas sorption studies

Layered structures of flexible mixed-linker metal-organic frameworks termed IRHs-(4 and 5) (IRH = Institut de Recherche sur l'Hydrogène) were synthesized by mixing cyclam, tetrakis(4-carboxyphenyl)benzene (TCPB), and copper and zinc metal salts respectively. The new materials characterized by single-crystal X-ray diffraction exhibited the features of HOFs and MOFs. Their structures are formed by coordination and hydrogen bonds that link metallocyclam (with Cu or Zn) and TCPB to a 2D sheet which is further packed to form a 3D structure with 1D microchannels. Remarkably, the as-synthesized IRHs-(4 and 5) contain DMF in the channels that can be exchanged with DCM and afterward removed from the framework by heating without losing their single-crystallinity. This enabled an easy elucidation of the structural transformations by single-crystal and powder X-ray diffraction analyses. Experimental studies of single-component adsorption isotherms of pure CO2, CH4, and N2 gases have been carried out for all activated IRHs. Based on the obtained adsorption isotherms, theoretical calculations using Ideal Adsorbed Solution Theory (IAST) have been performed to predict the selectivity of equimolar CO2/CH4 and CO2/N2 (1 : 1) binary mixtures. The simulations predicted outstanding selectivity for CO2/N2 than for CO2/CH4 at low pressures, reaching 185 for IRH-4 and 130 for IRH-5 at 1 bar.

Cyclotetrabenzoin Acetate: A Macrocyclic Porous Molecular Crystal for CO2 Separations by Pressure Swing Adsorption*

A porous molecular crystal (PMC) assembled by macrocyclic cyclotetrabenzoin acetate is an efficient adsorbent for CO₂ separations. The 7.1×7.1 Å square pore of PMC and its ester C=O groups play important roles in improving its affinity for CO₂ molecules. The benzene walls of macrocycle engage in an apparent [π⋅⋅⋅π] interaction with the molecule of CO₂ at low pressure. In addition, the polar carbonyl groups pointing inward the square channels reduce the size of aperture to a 5.0×5.0 Å square, which offers kinetic selectivity for CO₂ capture. The PMC features water tolerance and high structural stability under vacuum and various gas adsorption conditions, which are rare among intrinsically porous organic molecules. Most importantly, the moderate adsorbate-adsorbent interaction allows the PMC to be readily regenerated, and therefore applied to pressure swing adsorption processes. The eluted N₂ and CH₄ are obtained with over 99.9 % and 99.8 % purity, respectively, and the separation performance is stable for 30 cycles. Coupled with its easy synthesis, cyclotetrabenzoin acetate is a promising adsorbent for CO₂ separations from flue and natural gases.

Crystal structure of [3,10-bis-(4-fluoro-pheneth-yl)-1,3,5,8,10,12-hexa-aza-cyclo-tetra-deca-ne]nickel(II) diperchlorate

The square-planar nickel(II) title complex, [Ni(C24H36F2N6)](ClO4)2 or [NiL](ClO4)2 (L = 3,10-bis-(4-fluoro-pheneth-yl)-1,3,5,8,10,12-hexa-aza-cyclo-tetra-deca-ne) was synthesized by a one-pot reaction of template condensation and its X-ray crystal structure was determined. The nickel(II) ion lies close by a twofold axis and the complex displays whole-mol-ecule disorder. Ligand L, a hexa-aza-cyclo-tetra-decane ring having 4-fluoro-phenethyl side chains attached to uncoordinated nitro-gen atoms, adopts a trans III (R,R,S,S) configuration. The average Ni-N bond distance is 1.934 (9) Å, which is quite similar to those of other nickel(II) complexes with similar ligands. The nickel(II) ion is located 0.051 (7) Å above the least-squares plane through the four coordinated N atoms. The average C-N bond distance and C-N-C angle involving uncoordinated nitro-gen atoms are 1.425 (12) Å and 118.0 (9)°, respectively, indicating a significant contribution of sp 2 hybridization for these N atoms. The inter-molecular N-H⋯O, C-H⋯O/F hydrogen bonds of the complex form a network structure, which looks like a seamless floral lace pattern.

Structural Variation and Switchable Nonlinear Optical Behavior of Metal-Organic Frameworks

Two europium metal-organic frameworks (MOFs) based on the same ligand, named as ZJU-23-Eu and ZJU-24-Eu, are selectively synthesized by fine-tuning solvent contents to tailor the coordination modes. Eu atoms are eight-coordinated and nine-coordinated in ZJU-23-Eu and ZJU-24-Eu respectively, and their frameworks vary in both spatial connectivity and symmetry. The ligand not only has multiphoton response but also suitable triplet energy level (19 998 cm^-1 ) to sensitize Eu³⁺ . Thus ZJU-23-Eu exhibits characteristic emission of Eu³⁺ peaking at 614 nm via the energy transfer from the two-/three-photon excited ligand to Eu³⁺ , with its bidimensional layered structure benefiting this process. In contrast, the changed spatial connectivity in tridimensional ZJU-24-Eu narrows the distances between adjacent Eu³⁺ ions and reduces the density, resulting in poor two-photon excited fluorescence. Besides, noncentrosymmetric ZJU-24-Eu shows second harmonic generation (SHG) response with an intensity of ≈6.2 times relative to KH₂ PO₄ (KDP) microcrystalline powder while centrosymmetric ZJU-23-Eu cannot. These results have established two nonlinear optical (NLO) models based on MOFs to synchronously analyze the effects of two structural variables on different NLO behaviors, and provide ingenious ways to design MOF-based NLO devices with function on demand.

Crystal engineering of coordination polymers using flexible tetracarboxylate linkers with embedded cyclohexyldiamine cores

Flexible amine-functionalised tetracarboxylate ligands with different length arms generate a large variety of coordination polymers which notably lack topological consistency.

Dynamer and Metallodynamer Interconversion: An Alternative View to Metal Ion Complexation

A bifunctional molecule containing both a bidentate binding site for metal ions and an aminopyrimidine H-bond donor-acceptor site has been synthesized, and its properties, in its free and coordinated forms, have been established in solution and in the solid state by analytical and spectroscopic methods as well as by X-ray structure determinations. Structural characterization has shown that it forms a one-dimensional H-bonded polymeric assembly in the solid state, while spectroscopic measurements indicate that it also aggregates in solution. The reaction of a simple Fe(II) salt with this assembly results in the emergence of two geometrical isomers of the complex: [FeL₃](BF4)₂·9H₂O-C1 (meridional, mer) and [FeL₃]₂(SiF₆)(BF₄)₂·12H₂O-C2 (facial, fac). While, complex C1 in the solid state generates a one-dimensional H-bonded polymer involving just two ligands on each Fe center, with the chirality of the complex units alternating along the polymer chain, the structure of complex C2 shows NH···N interactions seen in both the ligand and mer complex (C1) structures to be completely absent. Physicochemical properties of the free and complexed ligand differ substantially.

Crystal structure of the one-dimensional coordination polymer formed by the macrocyclic [Ni(cyclam)]2+ cation and the dianion of di-phenyl-silanediylbis(4-benzoic acid)

The asymmetric unit of the title compound, catena-poly[[[(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ-4,4'-(di-phenyl-silanedi-yl)dibenz-o-ato-κ2 O:O'] sesquihydrate], {[Ni(C26H18O4Si)(C10H24N4)]·1.5H2O} n , consists of the halves of the centrosymmetric macrocyclic cation and the C 2-symmetric di-carboxyl-ate dianion and of the water mol-ecule of crystallization. The Ni2+ ion is coordinated by the four secondary N atoms of the macrocyclic ligand characterized by the most energetically favourable trans-III conformation and two mutually trans O atoms of the carboxyl-ate, forming a slightly tetra-gonally elongated trans-N4O2 octa-hedron. The crystals are composed of parallel polymeric chains of the macrocyclic cations linked by the anions of the acid running along the [101] direction. Each polymeric chain is bonded to four neighbouring ones via water mol-ecules providing O-H⋯O hydrogen bonds to the non-coordinated carboxyl O atoms to form a three-dimensional supra-molecular network.

A 2D coordination polymer assembled from a nickel(II) tetraazamacrocyclic cation and 4,4'-(dimethylsilanediyl)diphthalate(3-) linker

The preformed nickel(II) complex of the 14-membered macrocyclic ligand 1,4,8,11-tetraazacyclotetradecane (cyclam, L), when treated with 4,4'-(dimethylsilanediyl)diphthalic acid (H₄A) in a DMF/H₂O mixture (4:1 v/v) under heating, leads to [Ni(L)]₃(HA)₂·3DMF (I·DMF). Redissolution of this compound in a DMF/H₂O/MeOH mixture (4:1:30 v/v/v) with mild acidification under gentle heating results in the formation of a similar compound but containing water and methanol molecules of crystallization, [Ni(L)]₃(HA)₂·5H₂O·2MeOH (II·H₂O). At lower temperature and concentration of reactants and longer reaction time, single crystals of composition {[{Ni(L)}₃(HA)₂]·4CH₃OH}_n (II·MeOH) were isolated. Single-crystal X-ray diffraction analysis of this compound, which, according to PXRD is isostructural with II·H₂O but different from I·DMF, revealed its two-dimensional (2D) polymeric structure, i.e. poly[[bis{μ₃-4-[(4-carboxy-3-carboxylatophenyl)dimethylsilyl]benzene-1,2-dicarboxylato-κ³O¹:O²:O^3'}tris(1,4,8,11-tetraazacyclotetradecane-κ⁴N)trinickel(II)] methanol tetrasolvate], {[Ni₃(C₁₈H₁₃O₈Si)₂(C₁₀H₂₄N₄)₃]·4CH₃OH}_n. It is built up of the monoprotonated tricarboxylate HA^3- ligand coordinated in a monodentate manner in the axial positions of two crystallographically independent Ni^II cations, one of which is located on a crystallographic inversion centre. Both metal ions adopt a slightly tetragonally elongated trans-N₄O₂ octahedral geometry. The compound has a lamellar structure with polymeric layers oriented parallel to the (10-2) plane, which are in turn linked via hydrogen bonds involving protonated carboxylic acid groups of the ligand. Bulk compounds I·DMF and II·H₂O were characterized by FT-IR and diffuse reflectance spectroscopy and thermogravimetry, which provide evidence of their structural differences.

Coordination polymers of a bis-isophthalate bridging ligand with single molecule magnet behaviour of the CoII analogue

A linear diamine-bisisophthalate bridging linker N,N'-bis(1,3-dicarboxyphenyl-5-methylene)-1,3-dimethylpropanediamine, designed to incorporate amine/ammonium functionalities in the core of the ligand, has been isolated as the pentahydrate of its dihydrochloride salt (H6L)Cl2·5H2O. Using this compound, four new coordination polymers have been formed, namely poly-[M(H2L)]·4.5H2O (1M, where M = Co, Zn, Cd) and poly-[Cd(H2L)(OH2)]·DMF·7H2O (2). Compounds 1M are isostructural 2D coordination polymers that contain 1D channels occupied by water molecules. In the case of 1Co these form a well ordered hydrogen-bonding network as determined by single crystal X-ray studies. Compound 2, synthesised under similar conditions, is a 1D coordination polymer in which the metal is partially solvated. DC and AC magnetic studies of 1Co, which posseses a mononuclear cobalt(ii) node, revealed single molecule magnet behaviour (SMM) with an effective barrier height Ueff of 37.7 K and τ0 = 1.02 × 10-9 s, among the highest reported for CoII coordination polymers.

Solvent-triggered single-crystal-to-single-crystal transformation from a monomeric to polymeric copper(II) complex based on an aza macrocyclic ligand

Reversible solvent-triggered single-crystal-to-single-crystal (SCSC) transformations are observed between two copper(II) azamacrocyclic complexes: [Cu(C₁₆H₃₈N₆)(H₂O)₂](C₁₂H₆O₄) (1) and [Cu(C₁₆H₃₈N₆)(C₁₂H₆O₄)] (2). Complex (1) was prepared via self-assembly of a copper(II) azamacrocyclic complex containing butyl pendant groups, [Cu(C₁₆H₃₈N₆)(ClO₄)₂], with 2,7-naphthalenedicarboxylic acid. When monomeric compound (1) was immersed in CH₃OH, coordination polymer (2) was obtained, indicating a solvent-triggered SCSC transformation. Furthermore, when (2) was immersed in water, an reverse SCSC transformation from (2) to (1) occurred. Complex (1) presents a 3D supramolecular structure formed via intermolecular hydrogen-bonding interactions, whereas complex (2) features a 1D zigzag coordination polymer. The reversible SCSC transformation of (1) and (2) was characterized using single-crystal X-ray diffraction and in situ powder X-ray diffraction techniques. Despite its poor porosity, complex (2) displayed interesting CO₂ adsorption behaviour under CO₂ gas.

Syntheses and crystal structures of the one-dimensional coordination polymers formed by [Ni(cyclam)]2+ cations and 1,3-bis-(3-carb-oxy-prop-yl)tetra-methyl-disiloxane anions in different degrees of deprotonation

The title coordination polymers show different degrees of deprotonation of the disiloxane-di­carboxyl­ate bridging ligands: both contain tetra­gonally distorted trans-NiN₄O₂ octa­hedra.

The asymmetric units of the title compounds, namely, catena-poly[[(1,4,8,11-tetra­aza­cyclo­tetra­decane-κ⁴N¹,N⁴,N⁸,N¹¹)nickel(II)]-μ-1,3-bis­(3-carboxyl­ato­prop­yl)tetra­methyl­disiloxane-κ²O:O′], [Ni(C₁₀H₂₄O₅Si₂)(C₁₂H₂₄N₄)]_n (I), and catena-poly[[[(1,4,8,11-tetra­aza­cyclo­tetra­decane-κ⁴N¹,N⁴,N⁸,N¹¹)nickel(II)]-μ-4-({[(3-carb­oxy­prop­yl)di­methyl­sil­yl]­oxy}di­methyl­sil­yl)butano­ato-κ²O:O′] per­chlorate], {[Ni(C₁₀H₂₅O₅Si₂)(C₁₂H₂₄N₄)]ClO₄}_n (II), consist of one (in I) or two crystallographically non-equivalent (in II) centrosymmetric macrocyclic cations and one centrosymmetric dianion (in I) or two centrosymmetric monoanions (in II). In each compound, the metal ion is coordinated by the four secondary N atoms of the macrocyclic ligand, which adopts the most energetically stable trans-III conformation, and the mutually trans O atoms of the carboxyl­ate in a slightly tetra­gonally distorted trans-NiN₄O₂ octa­hedral coordination geometry. The crystals of both types of compounds are composed of parallel polymeric chains of the macrocyclic cations linked by the anions of the acid running along the [101] and [110] directions in I and II, respectively. In I, each polymeric chain is linked to four neighbouring ones by hydrogen bonding between the NH groups of the macrocycle and the carboxyl­ate O atoms, thus forming a three-dimensional supra­molecular network. In II, each polymeric chain contacts with only two neighbours, forming hydrogen bonds between the partially protonated carb­oxy­lic groups of the bridging ligand. As a result, a lamellar structure is formed with the layers oriented parallel to the (11) plane.

The first structural characterization of the proton-ated aza-cyclam ligand in catena-poly[[[(perchlorato)copper(II)]-μ-3-(3-carb-oxy-prop-yl)-1,5,8,12-tetra-aza-3-azonia-cyclo-tetra-deca-ne] bis-(per-chlorate)]

The asymmetric unit of the title com-pound, catena-poly[[[(perchlorato-κO)copper(II)]-μ-3-(3-carb-oxy-prop-yl)-1,5,8,12-tetra-aza-3-azonia-cyclo-tetra-decane-κ4 N 1,N 5,N 8,N 12] bis-(per-chlorate)], {[Cu(C13H30N5O2)(ClO4)](ClO4)2} n , (I), consists of a macrocyclic cation, one coordinated per-chlorate anion and two per-chlorate ions as counter-anions. The metal ion is coordinated in a tetra-gonally distorted octa-hedral geometry by the four secondary N atoms of the macrocyclic ligand, the mutually trans O atoms of the per-chlorate anion and the carbonyl O atom of the protonated carb-oxy-lic acid group of a neighbouring cation. The average equatorial Cu-N bond lengths [2.01 (6) Å] are significantly shorter than the axial Cu-O bond lengths [2.379 (8) Å for carboxyl-ate and average 2.62 (7) Å for disordered per-chlorate]. The coordinated macrocyclic ligand in (I) adopts the most energetically favourable trans-III conformation with an equatorial orientation of the substituent at the protonated distal 3-position N atom in a six-membered chelate ring. The coordination of the carb-oxy-lic acid group of the cation to a neighbouring com-plex unit results in the formation of infinite chains running along the b-axis direction, which are cross-linked by N-H⋯O hydrogen bonds between the secondary amine groups of the macrocycle and O atoms of the per-chlorate counter-anions to form sheets lying parallel to the (001) plane. Additionally, the extended structure of (I) is consolidated by numerous intra- and interchain C-H⋯O contacts.

Crystal structures of trans-di-aqua-(3-R-1,3,5,8,12-penta-aza-cyclo-tetra-deca-ne)copper(II) isophthalate hydrates (R = benzyl or pyridin-3-ylmethyl)

The asymmetric units of the title compounds, trans-di-aqua-(3-benzyl-1,3,5,8,12-penta-aza-cyclo-tetra-decane-κ4 N 1,N 5,N 8,N 12)copper(II) isophthalate monohydrate, [Cu(C16H29N5)(H2O)2](C8H4O4)·H2O, (I), and trans-di-aqua-[3-(pyridin-3-ylmeth-yl)-1,3,5,8,12-penta-aza-cyclo-tetra-decane-κ4 N 1,N 5,N 8,N 12]copper(II) iso-phthalate 0.9-hydrate, [Cu(C15H28N6)(H2O)2](C8H4O4)·0.9H2O, (II) consist of one di-aqua macrocyclic cation, one di-carboxyl-ate anion and uncoordinated water mol-ecule(s). In each compound, the metal ion is coordinated by the four secondary N atoms of the macrocyclic ligand and the mutually trans O atoms of the water mol-ecules in a tetra-gonally distorted octa-hedral geometry. The average equatorial Cu-N bond lengths are significantly shorter than the average axial Cu-O bond lengths [2.020 (9) versus 2.495 (12) Å and 2.015 (4) versus 2.507 (7) Å for (I) and (II), respectively]. The coordinated macrocyclic ligand in the cations of both compounds adopts the most energetically favorable trans-III conformation. In the crystals, the complex cations and counter-anions are connected via hydrogen-bonding inter-actions between the N-H groups of the macrocycles and the O-H groups of coordinated water mol-ecules as the proton donors and the O atoms of the carboxyl-ate as the proton acceptors. Additionally, as a result of O-H⋯O hydrogen bonding with the coordinated and water mol-ecules of crystallization, the isophthalate dianions form layers lying parallel to the (01) and (100) planes in (I) and (II), respectively.

Crystal structure of trans-di-aqua-(3,10-dimethyl-1,3,5,8,10,12-hexa-aza-cyclo-tetra-deca-ne)copper(II) pamoate

The asymmetric unit of the title compound, trans-di-aqua-(3,10-dimethyl-1,3,5,8,10,12-hexa-aza-cyclo-tetra-decane-κ⁴ N ¹,N ⁵,N ⁸,N ¹²)copper(II) 4,4'-methyl-ene-bis(3-hy-droxy-naphthalene-2-carboxyl-ate), [Cu(C₁₀H₂₆N₆)(H₂O)₂](C₂₃H₁₄O₆) {[Cu(L)(H₂O)₂](pam), where L = 3,10-dimethyl-1,3,5,8,10,12-hexa-aza-cyclo-tetra-decane and pam = dianion of pamoic acid} consists of two independent halves of the [Cu(L)(H₂O)₂]²⁺ cation and one di-carboxyl-ate anion. The Cu^II atoms, lying on inversion centres, are coordinated by the four secondary N atoms of the macrocyclic ligands and the mutually trans O atoms of the water mol-ecules in a tetra-gonally elongated octa-hedral geometry. The average equatorial Cu-N bond length is significantly shorter than the average axial Cu-O bond length [2.007 (10) and 2.486 (18) Å, respectively]. The macrocyclic ligand in the complex cations adopts the most energetically stable trans-III conformation. The complex cations and anions are connected via hydrogen-bonding inter-actions between the N-H groups of the macrocycles and the O-H groups of coordinated water mol-ecules as the proton donors and the O atoms of the carboxyl-ate as the proton acceptors into layers lying parallel to the (11) plane.