A Triple-Decker Heptadecanuclear (CuII)15(CrIII)2 Complex Assembled from Pentanuclear Metallacrowns

Sorption and Magnetic Properties of Oxalato-Based Trimetallic Open Framework Stabilized by Charge-Assisted Hydrogen Bonds

We report a new structure of {[Co(bpy)₂(ox)][{Cu₂(bpy)₂(ox)}Fe(ox)₃]}_n·8.5nH₂O NCU-1 presenting a rare ladder topology among oxalate-based coordination polymers with anionic chains composed of alternately arranged [Cu₂(bpy)₂(ox)]²⁺ and [Fe(ox)₃]³⁻ moieties. Along the a axis, they are separated by Co(III) units to give porous material with voids of 963.7 ų (16.9% of cell volume). The stability of this structure is assured by a network of stacking interactions and charge-assisted C-H…O hydrogen bonds formed between adjacent chains, adjacent cobalt(III) units, and alternately arranged cobalt(III) and chain motifs. The soaking experiment with acetonitrile and bromobenzene showed that water molecules (8.5 water molecules dispersed over 15 positions) are bonded tightly, despite partial occupancy. Water adsorption experiments are described by a D’arcy and Watt model being the sum of Langmuir and Dubinin–Serpinski isotherms. The amount of primary adsorption sites calculated from this model is equal 8.2 mol H₂O/mol, being very close to the value obtained from the XRD experiments and indicates that water was adsorbed mainly on the primary sites. The antiferromagnetic properties could be only approximately described with the simple Cu^II-ox-Cu^II dimer using H = −J·S₁·S₂, thus, considering non-trivial topology of the whole Cu-Fe chain, we developed our own general approach, based on the semiclassical model (SC) and molecular field (MF) model, to describe precisely the magnetic superexchange interactions in NCU-1. We established that Cu(II)-Cu(II) coupling dominates over multiple Cu(II)-Fe(III) interactions, with J_CuCu = −275(29) and J_CuFe = −3.8(1.6) cm⁻¹ and discussed the obtained values against the literature data.

Crystal structure and Hirshfeld surface analysis of poly[[bis-[μ4-N,N'-(1,3,5-oxadiazinane-3,5-di-yl)bis(carbamoyl-methano-ato)]nickel(II)tetra-potassium] 4.8-hydrate]

The title compound, {[K4Ni2(C7H6N4O7)2]·4.8H2O} n , was obtained as a result of a template reaction between oxalohydrazide-hydroxamic acid, formaldehyde and nickel(II) nitrate followed by partial hydrolysis of the formed inter-mediate. The two independent [Ni(C7H6N4O7)]2- complex anions exhibit pseudo-C S symmetry and consist of an almost planar metal-containing fragment and a 1,3,5-oxadiazinane ring with a chair conformation disposed nearly perpendicularly with respect to the former. The central NiII atom has a square-planar N2O2 coordination arrangement formed by two amide N and two carboxyl-ate O atoms. In the crystal, the nickel(II) complex anions form layers parallel to the ab plane. Neighboring complex anion layers are connected by layers of potassium cations for which two of the four independent cations are disordered over two sites [ratios of 0.54 (3):0.46 (3) and 0.9643 (15):0.0357 (15)]. The framework is stabilized by an extensive system of hydrogen bonds where the water mol-ecules act as donors and the carb-oxy-lic O atoms, the amide O atoms and the oxadiazinane N atoms act as acceptors.

Crystal structure of {N 1,N 3-bis-[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl-idene]-2,2-di-methyl-propane-1,3-di-amine}bis-(thio-cyanato-κN)iron(II)

The unit cell of the title compound, [FeII(NCS)2(C25H28N8)], consists of two charge-neutral complex mol-ecules related by an inversion centre. In the complex mol-ecule, the tetra-dentate ligand N 1,N 3-bis-[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl-ene]-2,2-di-methyl-propane-1,3-di-amine coordinates to the FeII ion through the N atoms of the 1,2,3-triazole moieties and aldimine groups. Two thio-cyanate anions, coordinating through their N atoms, complete the coordination sphere of the central ion. In the crystal, neighbouring mol-ecules are linked through weak C-H⋯π, C-H⋯S and C-H⋯N inter-actions into a two-dimensional network extending parallel to (011). The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H⋯H (35.2%), H⋯C/C⋯H (26.4%), H⋯S/S⋯H (19.3%) and H⋯N/N⋯H (13.9%).

Crystal structure of bis-{μ-2-[bis-(2-hy-droxy-eth-yl)amino]-ethano-lato}bis-(μ-3,5-di-methyl-pyrazolato)tricopper(II) dibromide sesquihydrate

In the title bicyclic trinuclear pyrazolate amino-alcohol complex, [Cu3(C5H7N2)2(C6H14NO3)2]Br2·1.5H2O, the central Cu atom lies on a center of symmetry and is involved in the formation of two five-membered rings. It has a coordination number of 4, is in a distorted tetra-hedral environment and is connected by the bridging oxygen atoms of the deprotonated OH groups of different amino-alcohol groups, and by the N atoms of deprotonated di-methyl-pyrazole ligands. The peripheral Cu atom is in a trigonal-bipyramidal coordination environment formed by the nitro-gen atom of the deprotonated bridging di-methyl-pyrazole unit, the bridging oxygen atom of the deprotonated OH group, two oxygen atoms of the protonated hy-droxy groups and the nitro-gen atom of tri-ethano-lamine. One of the C atoms and the Br- anion were found to be disordered over two positions with occupancy factors of 0.808 (9):0.192 (9) and 0.922 (3):0.078 (3), respectively.

Crystal structure of di-chlorido-1κCl,2κCl-(μ2-3,5-dimethyl-1H-pyrazolato-1κN 2:2κN 1)(3,5-dimethyl-1H-pyrazole-2κN 2){μ-2-[(2-hy-droxy-eth-yl)amino-1κ2 N,O]ethano-lato-1:2κ2 O:O}dicopper(II)

The title compound, [Cu2(C5H7N2)(C4H10NO2)Cl2(C5H8N2)], is a pyrazolate amino-alcohol complex which contains two di-methyl-pyrazole mol-ecules in monodentate and bidentate-bridged coordination modes and a monodeproton-ated di-ethano-lamine mol-ecule. Both copper atoms are involved in the formation of non-planar five-membered chelate rings. One Cu atom is in a distorted tetra-hedral environment formed by the pyridine nitro-gen atom of the protonated di-methyl-pyrazole mol-ecule, the N atom of the deprotonated bridged di-methyl-pyrazole, the Cl atom and the bridged O atom of the monodeprotonated di-ethano-lamine. The second Cu atom has an inter-mediate environment between trigonal bipyramidal and square pyramidal, formed by the N atom of the deprotonated bridged di-methyl-pyrazole, the Cl atom and the N atom of the amino-alcohol, and two O atoms of the deprotonated and protonated OH groups. In the crystal, N-H⋯Cl hydrogen bonds link the molecules into anti-symmetric chains running along the a-axis direction. Adjacent chains are connected by O-H⋯O hydrogen bonds involving the hydroxyl group as donor.

Mono- and ditopic hydroxamate ligands towards discrete and extended network architectures

A family of mono- and ditopic hydroxamic acids has been employed in the synthesis and structural and physical characterisation of discrete (0D) and (1- and 2-D) extended network coordination complexes. Examples of the latter include the 1-D coordination polymer {[Zn(ii)(L₃H)₂]·2MeOH}_n (5; L₃H₂ = 2-(methylamino)phenylhydroxamic acid) and the 2-D extended network {[Cu(ii)(L₂H)(H₂O)(NO₃)]·H₂O}_n (5; L₂H₂ = 4-amino-2-(acetoxy)phenylhydroxamic acid). The 12-MC-4 metallacrown [Cu(ii)₅(L₄H)₄(MeOH)₂(NO₃)₂]·3H₂O·4MeOH (7) represents the first metal complex constructed using the novel ligand N-hydroxy-2-[(2-hydroxy-3-methoxybenzyl)amino]benzamide (L₄H₃). Variable temperature magnetic susceptibility studies confirm strong antiferromagnetic exchange between the Cu(ii) centres in 7. Coordination polymer 5 shows photoluminescence in the blue region (λ_PL∼ 421-450 nm) with a bathochromic shift of the emission (∼15-30 nm) from solution to the solid state.

Diaquabis[4-(dimethylamino)pyridine-κN 1]bis[2-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)acetato-κO 1]cobalt(II)

In the mononuclear title complex, [Co(C10H6NO4)2(C7H10N2)2(H2O)2], the CoII ion is located on an inversion centre and has a distorted octahedral coordination geometry of type CoN2O4 by two N atoms from the two 4-(dimethylamino)pyridine (DMAP) ligands, two carboxylate O atoms from the two deprotonated N-phthaloylglycine (Nphgly) ligands [systematic name: 2-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)acetate] and two coordination water molecules. In the crystal, O—H...O, C—H...O hydrogen bonds and π–π stacking interactions link the molecules into the supramolecular structure.

Crystal structure and Hirshfeld surface analysis of (succinato-κO)[N,N,N',N'-tetra-kis-(2-hy-droxy-eth-yl)ethyl-enedi-amine-κ5 O,N,N',O',O'']nickel(II) tetra-hydrate

In the title compound, [Ni(C10H24N2O4)(C4H4O4)]·4H2O, the NiII cation is octa-hedrally coordinated by one O atom of the succinate anion and three O atoms and two N atoms from an N,N,N',N'-tetra-kis-(2-hy-droxy-eth-yl)ethyl-enedi-amine mol-ecule. In the crystal, mol-ecules are linked by O-H⋯O and C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular architecture. Hirshfeld surface analyses and two-dimensional fingerprint plots were used to analyse the inter-molecular inter-actions present in the crystal, indicating that the most important contributions for the crystal packing are from H⋯H (63.3%) and H⋯O/O⋯H (34.5%) inter-actions.

Crystal structure of bis-[(S)-2-(2-hy-droxy-benzyl-amino)-4-methyl-penta-noato-κ2 N,O 1](1,10-phenanthroline-κ2 N,N')cadmium dihydrate

The asymmetric unit of the mononuclear mixed-ligand title complex, [Cd(C13H18NO3)2(C12H8N2)]·2H2O, contains two crystallographically independent mol-ecules that differ insignificantly in their geometrical parameters. In both, the CdII cation lies on a twofold rotation axis and is coordinated in a distorted octa-hedral fashion to two monodeprotonated residues of the l-leucine-derived ligand (S)-2-(2-hy-droxy-benzyl-amino)-4-methyl-penta-noic acid (L), as well as to a 1,10-phenanthroline ligand in a κ2 N,N' mode. The former coordinate in an N,O-chelating mode, exhibiting a trans-N,N' mutual disposition. The phenolic oxygen donor groups remain protonated and do not coordinate to the cation but take part in intra- and inter-molecular hydrogen bonds. In the crystal, O-H⋯O hydrogen bonding results in the formation of a three-dimensional network structure. The contribution to the electron density of two disordered water mol-ecules was removed with the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The studied crystal was refined as a two-component inversion twin. The title complex was also characterized by IR and 1H NMR spectroscopic methods.

Synthesis, crystallographic analysis and Hirshfeld surface analysis of 4-bromo-2-{[2-(5-bromo-2-nitro-phen-yl)hydrazin-1-yl-idene]meth-yl}-5-fluoro-phenol

The title compound, C13H8Br2FN3O3, is nearly planar with a dihedral angle of 10.6 (4)° between the two benzene rings. Intra-molecular N-H⋯O and O-H⋯N hydrogen bonds occur. In the crystal, the mol-ecules are linked by weak C-H⋯O and C-H⋯Br hydrogen bonds. The roles of the inter-molecular inter-actions in the crystal packing were clarified using Hirshfeld surface analysis.

Crystal structure of N-hy-droxy-quinoline-2-carboxamide monohydrate

The title compound, C10H8N2O2·H2O, consists of an N-hy-droxy-quinoline-2-carboxamide mol-ecule in the keto tautomeric form and a water mol-ecule connected through an O-H⋯O hydrogen bond. The N-hy-droxy-quinoline-2-carboxamide mol-ecule has a nearly planar structure [maximum deviation = 0.062 (1) Å] and only the hy-droxy H atom deviates significantly from the mol-ecule plane. In the crystal, π-π stacking between the aromatic rings [inter-centroid distance = 3.887 (1) Å] and inter-molecular O-H⋯O hydrogen bonds organize the crystal components into columns extending along the b-axis direction.

Crystal structure of bis-(μ-N-hy-droxy-picolin-amid-ato)bis-[bis-(N-hy-droxy-picolinamide)-sodium]

The title compound, [Na2(C6H5N2O2)2(C6H6N2O2)4], is a centrosymmetric coordination dimer based on the sodium(I) salt of N-hy-droxy-picolinamide. The mol-ecule has an {Na2O6(μ-O)2} core with two bridging carbonyl O atoms and two hydroxamate O atoms of two mono-deprotonated residues of N-hy-droxy-picolinamide, while two neutral N-hy-droxy-picolinamide mol-ecules are coordinated in a monodentate manner to each sodium ion via the carbonyl O atoms [the Na-O distances range from 2.3044 (2) to 2.3716 (2) Å]. The penta-coordinated sodium ion exhibits a distorted trigonal-pyramidal coordination polyhedron. In the crystal, the coordination dimers are linked into chains along the c axis via N-H⋯O and N-H⋯N hydrogen bonds; the chains are linked into a two-dimensional framework parallel to (100) via weak C-H⋯O and π-π stacking inter-actions.

Spontaneous ligand nitrosation and self-assembly into a pentacopper metallacrown complex

Acetylacetonedioxime is spontaneously nitrosated in the presence of Cu(ii) nitrate; four of the nitrosated ligands and five Cu ions self-assemble into a metallacrown complex.

Crystal structure of μ-oxalodi-hydroxamato-bis-[(2,2'-bipyrid-yl)(di-methyl sulfoxide-κO)copper(II)] bis-(perchlorate)

The centrosymmetric binuclear complex, [Cu2(C2H2N2O4)(C10H8N2)2(C2H6OS)2](ClO4)2, contains two copper(II) ions, connected through an N-deprotonated oxalodi-hydroxamic acid dianion, two terminal 2,2'-bi-pyridine ligands, and two apically coordinating dimethylsulfoxide mol-ecules. Two non-coordinating perchlorate anions assure electrical neutrality. The copper(II) ions in the complex dication [Cu2(C10H8N2)2(μ-C2H2N2O4)(C2H6SO)2](2+) are in an O2N3 square-pyramidal donor environment, the Cu-Cu separation being 5.2949 (4) Å. Two hydroxamate groups in the deprotonated oxalodi-hydroxamic acid are located trans to one each other. In the crystal, O-H⋯O and C-H⋯O hydrogen bonds link the complex cations to the perchlorate anions. Further C-H⋯O hydrogen bonds combine with π-π contacts with a centroid-to-centroid separation of 3.6371 (12) Å to stack the mol-ecules along the a-axis direction.

Crystal structure of N-hy-droxy-picolinamide monohydrate

The crystal structure of the title compound, C6H6N2O2·H2O, consists of N-hy-droxy-picolinamide and water mol-ecules connected through O-H⋯O and N-H⋯N hydrogen bonds. The O-H⋯O inter-actions and π-π stacking inter-actions between the pyridine rings [centroid-centroid distance = 3.427 (1) Å] organize the components into columns extending along the b axis and the N-H⋯N hydrogen bonds link these columns into a two-dimensional framework parallel to (100). The N-hy-droxy-picolinamide mol-ecule adopts a strongly flattened conformation and only the O-H group H atom deviates significantly from the mol-ecule best plane. The dihedral angle between the hydroxamic group and the pyridine ring is 5.6 (2)°. The conformation about the hydroxamic group C-N bond is Z and that about the C-C bond between the pyridine and hydroxamic groups is E.

Crystal structure of poly[di-aqua-(μ-2-carb-oxy-acetato-κ(3) O,O':O'')(2-carb-oxy-acetato-κO)di-μ-chlorido-dicobalt(II)]

In the title coordination polymer, [Co(C₃H₃O₄)Cl(H₂O)]_n, the sixfold coordination environment of the Co^II atom consists of two O atoms from a chelating hydrogen malonate anion (HMal⁻), one O atom originating from a μ₂-bridging malonate ligand (HMal⁻), one O atom from a water mol­ecule and two μ₂-bridging Cl⁻ atoms, connecting neighbouring Co₂Cl₄ motifs into a two-dimensional polymer extending parallel to (001). Inter­layer O—H⋯O hydrogen bonds link the layers into a three-dimensional network.

The asymmetric unit of the title polymer, [Co₂(C₃H₃O₄)₂Cl₂(H₂O)₂]_n, comprises one Co^II atom, one water mol­ecule, one singly deprotonated malonic acid mol­ecule (HMal⁻; systematic name 2-carb­oxy­acetate) and one Cl⁻ anion. The Co^II atom is octa­hedrally coordinated by the O atom of a water mol­ecule, by one terminally bound carboxyl­ate O atom of an HMal⁻ anion and by two O atoms of a chelating HMal⁻ anion, as well as by two Cl⁻ anions. The Cl⁻ anions bridge two Co^II atoms, forming a centrosymmetric Co₂Cl₂ core. Each malonate ligand is involved in the formation of six-membered chelate rings involving one Co^II atom of the dinuclear unit and at the same time is coordinating to another Co^II atom of a neighbouring dinuclear unit in a bridging mode. The combination of chelating and bridging coordination modes leads to the formation of a two-dimensional coordination polymer extending parallel to (001). Within a layer, O—H_water⋯Cl and O—H_water⋯O hydrogen bonds are present. Adjacent layers are linked through O—H⋯O=C hydrogen bonds involving the carb­oxy­lic acid OH and carbonyl groups.

22-Azametallacrown-8 complex with a triazole-bridged ligand: synthesis, structure and magnetic properties

Reaction of Mn(OAc)2·4H2O with the H2L ligand affords a new manganese 22-MC-8 azametallacrown [Mn8(μ3-O)2(μ3-OH)2(μ2-OH)2(L)6(OAc)2(OH2)4]·2DMF (H2L = 3-(2-oxyphenyl)-5-(pyrazin-2-yl)-1,2,4-triazole). The structural analysis of the complex reveals that the azaMC ring possesses -[Mn-O-Mn-N-N-Mn-N-N-Mn-N-N]- connectivity. The magnetic behavior of the complex shows the dominant antiferromagnetic interactions between the manganese ions with S = 4 and the frequency-dependent out-of-phase signal.

Crystal structure of 2-hy-droxy-imino-2-(pyridin-2-yl)-N'-[1-(pyridin-2-yl)ethyl-idene]acetohydrazide

The mol­ecule of the title compound is approximately planar with the planes of the two pyridine rings inclined to one another by 5.51 (7)°. In the crystal, mol­ecules are linked by bifurcated O—H⋯(O,N) hydrogen bonds, forming inversion dimers, which are in turn linked via C—H⋯O and C—H⋯N hydrogen bonds, forming sheets lying parallel to (502).

The mol­ecule of the title compound, C₁₄H₁₃N₅O₂, is approximately planar (r.m.s deviation for all non-H atoms = 0.093 Å), with the planes of the two pyridine rings inclined to one another by 5.51 (7)°. The oxime group is syn to the amide group, probably due to the formation of an intra­molecular N—H⋯N hydrogen bond that forms an S(6) ring motif. In the crystal, mol­ecules are linked by pairs of bifurcated O—H⋯(O,N) hydrogen bonds, forming inversion dimers. The latter are linked via C—H⋯O and C—H⋯N hydrogen bonds, forming sheets lying parallel to (502). The sheets are linked via π–π stacking inter­actions [inter-centroid distance = 3.7588 (9) Å], involving the pyridine rings of inversion-related mol­ecules, forming a three-dimensional structure.

Synthesis, structure and magnetic properties of phenylhydroxamate-based coordination clusters

The strategic recombination of preformed coordination clusters in the presence of polymodal bridging ligands has successfully led to the characterisation of five new compounds of structural and magnetic interest. Indeed using the dinuclear complex [M2(H2O)(piv)4(Hpiv)4] (M = Co, Ni; Hpiv = pivalic acid) as starting material and reacting it with phenylhydroxamic acid (H2pha) has yielded the four tetrametallic coordination clusters [Co4(Hpha)2(piv)6(Hpiv)4] (1), [Ni4(Hpha)2(piv)6(Hpiv)2(DMF)2] (2), [Co4(Hpha)2(piv)6(EtOH)2(H2O)2] (3), [Ni4(Hpha)2(piv)6(EtOH)2(H2O)2] (4) and the hexanuclear complex [Co6(Hpha)4(piv)8(EtOH)2]·EtOH (5). All the compounds have been structurally characterised revealing a particular binding mode for the hydroxamate ligand. The study of their magnetic properties has been performed and the modelling of these properties has been done using the appropriate hamiltonians for each compound. The experimental data and their modelling show non-zero spin ground states for compounds 4 and 5.

Enforcement of a high-spin ground state for the first 3d heterometallic 12-metallacrown-4 complex

Applying a novel magnetic director approach, we have realized Cu(ii)(DMF)₂Cl₂[12-MC_{Fe(III)N(Shi)}-4](DMF)₄·2DMF as the first heterometallic transition metal 12-MC-4 complex in order to provide this type of compound with a high-spin ground state.