Heterometallic Mixed-Valence Copper(I,II) Cyanides that were Tuned by Using the Chelate Effect: Discovery of Famous Cairo Pentagonal Tiling and Unprecedented (3,4)-Connected {83}2{86} Topological 3D Net

A novel tetrazolate- and cyanide-bridged three-dimensional heterometallic coordination polymer: crystal structure, thermal stability and magnetic properties

By using environmentally friendly K3[Co(CN)6] as a cyanide source, the solvothermal reaction of CuCl2 and tetrazole (Htta) led to a novel tetrazolate- and cyanide-bridged three-dimensional heterometallic CuII–CoIII complex, namely poly[[hexa-μ2-cyanido-κ12 C:N-pentakis(μ3-tetrazolato-κ3 N 1:N 2:N 4)cobalt(III)tetracopper(II)] monohydrate], {[CoIIICuII 4(CHN4)5(CN)6]·H2O} n , (I). The crystal structure analysis reveals that it is the first example of a (6,8,8)-connected three-dimensional framework with a unique topology, constructed from anionic [Co(CN)6]3− and cationic [(Cu1)2(tta)2]2+ and [(Cu2Cu3)(tta)3]+ units through μ2-cyanide and μ3-tetrazolate linkers. The compound was further characterized by thermal analysis, vibrational spectroscopy (FT–IR), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM–EDS) and magnetic measurements. The magnetic investigation indicates that the complex exhibits antiferromagnetic coupling between adjacent CuII cations.

Coordination Polymers and Cage-Containing Frameworks in Uranyl Ion Complexes with rac- and (1R,2R)-trans-1,2-Cyclohexanedicarboxylates: Consequences of Chirality

Racemic and enantiopure (1R,2R) forms of trans-1,2-cyclohexanedicarboxylic acid (H₂chdc and R-H₂chdc, respectively) have been used in the synthesis of a series of 13 uranyl ion complexes, all obtained under solvo-hydrothermal conditions and in the presence of additional metal cations and/or N-donor ligands. While the homometallic complex [UO₂(R-chdc)] (1) was only obtained with the enantiopure ligand, complexes [UO₂(chdc)(THF)] (2), [UO₂(chdc)(DMF)] (3), and [UO₂(chdc)(NMP)] (4), with a coordinated solvent molecule, were obtained from the racemic form only; all crystallize as two-dimensional (2D) assemblies. The two complexes [UO₂(chdc)(bipy)](5) and [UO₂(R-chdc)(bipy)] (6), where bipy is 2,2'-bipyridine, are isomorphous since 5 crystallizes as a racemic conglomerate; they are both one-dimensional (1D) homochiral, helical polymers. The heterometallic complexes [UO₂Cu(chdc)₂(bipy)(H₂O)]·H₂O (7) and [UO₂Cu(R-chdc)₂(bipy)]·3H₂O (8) crystallize as a 1D or a 2D species, respectively, while [UO₂Cd(R-chdc)₂(H₂O)₂]·H₂O (9) displays a 2D arrangement with the unusual Cairo pentagonal tiling topology. The four complexes [(UO₂)₂Na₂(chdc)₃(H₂O)₂] (10), [(UO₂)₂Ag₂(chdc)₃(H₂O)₂] (11), [(UO₂)₂Na₂(R-chdc)₃(H₂O)₂] (12), and [(UO₂)₂Pb(R-chdc)₃(H₂O)₄] (13) are closely related, all of them containing tetranuclear, pseudotetrahedral [(UO₂)₄(chdc/R-chdc)₆]^4- cage motifs, that are assembled into a three-dimensional (3D) framework by bridging counterions (Na⁺, Ag⁺, or Pb²⁺). These cages define a new pathway to assembly of such species based on the unique coordination geometry of uranyl ion, differing from the widely exploited use of octahedral metal ions.

A Chiral 3 D Net with 2 D Cairo Pentagonal Tiling Projection in Site-Modified CuCN/CuSCN Networks

A novel isohedral 3-periodic net (i.e. a net with one kind of tile), showing a Cairo pentagonal tiling projection on the Euclidean plane, has been identified in a series of site-modified CuCN/CuSCN networks, namely, [Cu₆ (SCN)₂ (CN)₆ ⋅Ni(tpy)₂ ]_n (1), [Cu₆ (SCN)(CN)₇ ⋅Ni(tpy)₂ ]_n (2) and [Cu₆ (CN)₈ ⋅Ni(tpy)₂ ]_n (3) (tpy=2,2':6'',2''-terpyridine). These infinite inclusion compounds were prepared via a solvothermal sulfur migration reaction with subtle modification to fine-tune the sulfur content. The chiroptical activity of single crystals, which arises from the intrinsically chiral net, was confirmed by X-ray diffraction and solid-state circular dichroism spectra.

Synthesis, crystal structure and magnetic properties of a two-dimensional cyanide-based heterometallic coordination polymer with cationic piperazinium ligands: poly[aquatetra-μ2-cyanido-κ(8)C:N-dicyanido-κ(2)C-(piperazinium-κN(4))cobalt(III)copper(II)]

Cyanide as a bridge can be used to construct homo- and heterometallic complexes with intriguing structures and interesting magnetic properties. These ligands can generate diverse structures, including clusters, one-dimensional chains, two-dimensional layers and three-dimensional frameworks. The title cyanide-bridged Cu(II)-Co(III) heterometallic compound, [Cu(II)Co(III)(CN)6(C4H11N2)(H2O)]n, has been synthesized and characterized by single-crystal X-ray diffraction analysis, magnetic measurement, thermal study, vibrational spectroscopy (FT-IR) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS). The crystal structure analysis revealed that it has a two-dimensional grid-like structure built up of [Cu(Hpip)(H2O)](3+) cations (Hpip is piperazinium) and [Co(CN)6](3-) anions that are linked through bridging cyanide ligands. The overall three-dimensional supramolecular network is expanded by a combination of interlayer O-H...N and N-H...O hydrogen bonds involving the coordinated water molecules and the N atoms of the nonbridging cyanide groups and monodentate cationic piperazinium ligands. A magnetic investigation shows that antiferromagnetic interactions exist in the title compound.

Mixed-valence copper(i,ii) complexes with 4-(1H-pyrazol-1-yl)-6-R-pyrimidines: from ionic structures to coordination polymers

All copper ions in a copper(i,ii) mixed-valence 1D-polymer show tetrahedral coordination cores, CuNBr₃ and CuN₂Br₂, which is extremely rare for mixed-valence copper(i,ii) compounds.

Chemistry and structure by design: ordered CuNi(CN)4 sheets with copper(ii) in a square-planar environment

Cu(ii) has been stabilised with square-planar coordination in a cyanide-only environment in the layered semiconducting material, copper–nickel cyanide, CuNi(CN)₄, which shows 2-D negative thermal expansion.

Syntheses, characterization, and properties of five coordination compounds based on the ligand tetrakis(4-pyridyloxymethylene)methane

Based on tetrakis(4-pyridyloxymethylene)methane (TPOM) and different carboxylates, five new MOFs with structures of high dimension and mutual interpenetration have been successfully synthesized.