Synthesis, crystal structures and magnetic properties of tricyanomethanide-containing copper(II) complexes

Field-induced slow magnetic relaxation in pseudooctahedral cobalt(ii) complexes with positive axial and large rhombic anisotropy

The preparation, X-ray crystal structure, spectroscopic and variable-temperature dc and ac magnetic properties of two six-coordinate cobalt(ii) complexes of formula [Co(bim)₄(tcm)₂] (1) and [Co(bmim)₄(tcm)₂] (2) are reported.

Low-dimensional compounds containing cyanido groups. Part XXXIV. Structure, spectral and magnetic properties of the first complex with pyridylbenzimidazole and nonlinear pseudohalide anion

From the system CuCl2 – pbi – NaN(CN)2 −, polymeric [CuCl(μ1,5-dca)(pbi)]n·nH2O (1) complex (dca=dicyanamide, pbi=2-(2-pyridyl)benzimidazole) was isolated and characterized by structure analysis, spectral and magnetic measurements. Infrared spectroscopy confirmed the presence of pbi, dca and water molecules in 1. Its solid-state structure is formed by infinite chains running along the b axis. In the chain, the Cu(II) atom is penta-coordinated by two nitrogen atoms of chelate pbi ligand, by two nitrile nitrogen atoms of bridging μ1,5-dca and by chloride ligand which occupies the apical position of tetragonal pyramid around the Cu(II) atom. Asymmetric unit is supplemented by one molecule of solvated water, which along with chlorine atom serves as acceptors in intermolecular hydrogen bonds and along with π–π interactions create a 3D supramolecular structure. Magnetic measurements revealed the presence of a weak ferromagnetic exchange interaction J/kB =0.11 K.

Design of 3d–4f molecular squares through the [Fe{(HB(pz)3)}(CN)3]− metalloligand

A new series of cyanido-bridged {FeIII2LnIII2} heterobimetallic molecular squares [Ln = La (1), Gd (2), Tb (3) and Dy (4)] has been prepared and magneto-structurally investigated.

Study of the complex formation between the [Cu(bpca)]+ secondary building unit and the aromatic N donors 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz) and 1,3-bis(4-pyridyl)propane (bpp)

Alternating anionic and cationic slices (1) and supramolecular layers (2) resulted from the assembly between [Cu(bpca)]⁺ and polypyridine ligands.

Complexation of different transition metals with 4,4'-dimethyl-2,2'-bipyridine: Crystal structure, UV spectra and Hirshfeld surfaces

Four new complexes, [Co(dmbpy)2(dca)2]·CH3OH (1), [Ni(dmbpy)2(dca)2]·CH3OH (2), [Zn(dmbpy)2(dca)2]·(3) and [Cu(dmbpy)2(OH)2]·5H2O (4) (dca=dicyanamide), derived from 4,4'-dimethyl-2,2'-bipyridine (dmbpy) have been synthesized and characterized by elemental analysis, TGA and single-crystal X-ray diffraction. Crystal structures and Hirshfeld surfaces analysis revealed that the complexes 1-3 were mainly supported by OH⋯N, CH⋯N and π⋯π intermolecular interactions, and for complex 4, the uncoordinated water molecules play a key role in the construction of the 3D stacking motif. UV spectrum measurements demonstrate that all of the complexes show typical metal to ligand charge transfer (MLCT) absorption bands between 301 and 306nm. Moreover, after complexation, the absorption maximum bands about intraligand π→π* transitions similarly show slightly red shift compared to dmbpy ligand, consisting with the DFT calculations.

Crystal structures of (1,4,7,10-tetra-aza-cyclo-dodecane-κ(4) N)bis-(tri-cyano-methanido-κN)nickel and (1,4,7,10-tetra-aza-cyclo-dodecane-κ(4) N)(tri-cyano-methanido-κN)copper tri-cyano-methanide

The structures of two mononuclear transition-metal complexes with tri-cyano-methanide (tcm(-)) and 1,4,7,10-tetra-aza-cyclo-dodecane (cyclen) ligands, [Ni(C4N3)2(C8H20N4)], (I), and [Cu(C4N3)(C8H20N4)](C4N3), (II), are reported. In the neutral complex (I), the nickel cation is coordinated by one cyclen ligand and two monodentate N-bound tcm(-) anions in a distorted octa-hedral geometry. The tcm(-) ligands are mutually cis. The Cu(II) atom in (II) displays a distorted tetra-gonal-pyramidal geometry, with the four N-donor atoms of the cyclen ligand in the equatorial plane, and one tcm(-) anion bound through a single N atom in an axial site, forming a monocation. The second tcm(-) molecule acts as a counter-ion not directly coordinating to the copper cation. In both (I) and (II), extensive series of N-H⋯N and C-H⋯N hydrogen bonds generate three-dimensional network structures.

Metamagnetic behaviour in a new Cu(II)Re(IV) chain based on the hexachlororhenate(IV) anion

A new chloro-bridged heterobimetallic Cu(II)Re(IV) chain of formula {Cu(pyim)(Him)2ReCl6}n·MeCN (·MeCN) has been prepared and magnetostructurally characterised. Compound is the first example of the [Re(IV)Cl6](2-) anion acting as a metalloligand towards a paramagnetic metal ion.

Synthesis, crystal structure and magnetic properties of the complex [ReCl3(tppz)]·MeCN

The paper reports the synthesis, X-ray structure and a deep analysis of the variable-temperature magnetic data of the new complex [ReCl₃(tppz)]·MeCN being a very scarce example of mononuclear Re(iii) complexes incorporating nitrogen donor ligands.

Ligand effects on the structure and magnetic properties of alternating copper(II) chains with 2,2'-bipyrimidine- and polymethyl-substituted pyrazolates as bridging ligands

A novel series of heteroleptic copper(II) compounds of formulas {[Cu2(μ-H2O)(μ-pz)2(μ-bpm)(ClO4)(H2O)]ClO4·2H2O}n (1), {[Cu2(μ-H2O)(μ-3-Mepz)2(μ-bpm)](ClO4)2·2H2O}n (2), and {[Cu2(μ-OH)(μ-3,5-Me2pz)(μ-bpm)(H-3,5-Me2pz)2](ClO4)2}n (3) [bpm = 2,2'-bipyrimidine, Hpz = pyrazole, H-3-Mepz = 3-methylpyrazole, and H-3,5-Me2pz = 3,5-dimethylpyrazole] have been synthesized and structurally characterized by X-ray diffraction methods. The crystal structures of 1 and 2 consist of copper(II) chains with regular alternating bpm and bis(pyrazolate)(aqua) bridges, whereas that of 3 is made up of copper(II) chains with regular alternating bpm and (pyrazolate)(hydroxo) bridges. The copper centers are six- (1) or five-coordinate (2) in axially elongated, octahedral (1) or square-pyramidal (2) environments in 1 and 2, whereas they are five-coordinate in distorted trigonal-bipyramidal surroundings in 3. The values of the copper-copper separations across the bpm/pyrazolate bridges are 5.5442(7)/3.3131(6) (1), 5.538(1)/3.235(1) (2), and 5.7673(7)/3.3220(6) Å (3). The magnetic properties of 1-3 have been investigated in the temperature range of 25-300 K. The analysis of their magnetic susceptibility data through the isotropic Hamiltonian for an alternating antiferromagnetic copper(II) chain model [H = -J∑i=1-n/2 (S2i·S2i-1 + αS2i·S2i+1), with α = J'/J and Si = SCu = 1/2] reveals the presence of a strong to moderate antiferromagnetic coupling through the bis(pyrazolate)(aqua) [-J = 217 (1) and 215 cm(-1) (2)] and (pyrazolate)(hydroxo) bridges [-J = 153 cm(-1) (3)], respectively, whereas a strong to weak antiferromagnetic coupling occurs through the bis-bidentate bpm [-J' = 211 (1), 213 (2), and 44 cm(-1) (3)]. A simple orbital analysis of the magnetic exchange interaction within the bpm- and pyrazolate-bridged dicopper(II) fragments of 1-3 visualizes the σ-type pathways involving the (dx(2)-y(2)) (1 and 2) or d(z(2)) (3) magnetic orbitals on each metal ion, which account for the variation of the magnetic properties in these three novel examples of one-dimensional copper(II) compounds with regular alternating intrachain antiferromagnetic interactions.

Low-dimensional compounds containing cyanide groups. XXV. Synthesis, spectroscopic properties and crystal structures of two ionic iron(II) complexes with tricyanomethanide: tris(1,10-phenanthroline-κ(2)N,N')iron(II) bis(tricyanomethanide) and tris(2,2'-bipyridine-κ(2)N,N')iron(II) bis(tricyanomethanide) sesquihydrate

Two new diamagnetic coordination compounds, [Fe(phen)3][C(CN)3]2, (I), and [Fe(bpy)3][C(CN)3]2·1.5H2O, (II), have been synthesized and characterized by single-crystal X-ray diffraction analysis, and IR and UV-Vis spectroscopy (phen is 1,10-phenanthroline, C12H8N2, and bpy is 2,2'-bipyridine, C10H8N2). Both compounds are ionic with distorted octahedral [Fe(phen)3](2+) or [Fe(bpy)3](2+) complex cations, with average Fe-N distances of 1.977 (2) and 1.971 (3) Å, respectively, and two uncoordinated planar tricyanomethanide, or [C(CN)3](-), counter-anions balancing the positive charges of the cations. Solvent water molecules and tcm anions in (II) are linked via O-H...N hydrogen bonds into negatively charged layers and the interlayer space is filled by [Fe(bpy)3](2+) cations. The structures of (I) and (II) are stabilized by π-π interactions between the stacked aromatic rings of the phen ligands of two adjacent cations and by O-H...N hydrogen bonds, respectively, and also by π-π stacking interactions between phen and tcm units in (I).

catena-Poly[[(1,10-phenanthroline-κ(2) N,N')copper(II)]-μ-2,2'-iminodibenzoato-κ(4) O,O':O'',O''']

The structure of the title compound, [Cu(C₁₄H₉NO₄)(C₁₂H₈N₂)]_n, consists of zigzag polymeric chains along the c axis. The asymmetric unit contains one Cu^II atom which is coordinated by one 2,2′-imino­dibenzoate ligand and a one phenanthroline unit. Two intra­molecular N—H⋯O hydrogen bonds occur. The supra­molecular structure is characterized by weak C—H⋯O hydrogen bonds and π–π stacking inter­actions, forming a three-dimensional supramolecular network. The shortest centroid–centroid distances between neighbouring phenanthroline aromatic rings and 2,2′-imino­dibenzoate rings are 3.684 (1) and 3.640 Å, respectively. The shortest intra­chain Cu⋯Cu distance is 7.2885 (9) and the shortest Cu⋯Cu distance between Cu atoms in different chains is 7.1103 (6) Å.

Bis(2,2'-bipyridyl dioxide-κN,N')bis-(tricyano-methanido)cobalt(II) dihydrate

In the title compound, [Co(C₄N₃)₂(C₁₀H₈N₂O₂)]·2H₂O, a novel tricyano­methanide complex, the Co^II atom is located on an inversion center and has a distorted octa­hedral coordination with two 2,2′-bipyridyl dioxide (dpdo) mol­ecules and two trans tricyano­methanide (tcm) anions. The equatorial plane is formed by the four O atoms of the two chelating dpdo ligands, with one N atom of each of the two tcm ligands occupying an apical position. There is a disordered solvent water mol­ecule in the asymmetric unit (occupancy ratio 0.63:0.37). These water mol­ecules result in the formation of O—H⋯O and O—H⋯N hydrogen bonds, building a layer parallel to (100). The layers are linked by C—H⋯N hydrogen-bonding inter­actions, leading to a three-dimensional network.

Bis(2,2':6',2''-terpyridine)cobalt(II) bis-(tricyano-methanide)

The title complex, [Co(C₁₅H₁₁N₃)₂](C₄N₃)₂, is built up from discrete [Co(terpy)₂]²⁺ cations (terpy is 2,2′:6′,2′′-terpyridine) and [C(CN)₃]⁻ anions. In the cation, the Co^II atom is coordinated by two terpy mol­ecules, giving a distorted octa­hedral geometry. The tricyano­methanide anions are not directly coordinated to the Co^II atom, but some weak C—H⋯N hydrogen bonds involving the terminal N atoms of the tricyaomethanide ions and the terpyridine H atoms link anions and cations building a three-dimensional network.

catena-Poly[[(2,2':6',2''-terpyridine-κN,N',N'')(tricyano-methanido-κN)nickel(II)]-μ-tricyano-methanido]

In the title complex, [Ni(C₄N₃)₂(C₁₅H₁₁N₃)]_n, each of the two different Ni^II atoms is coordinated by one 2,2′:6′2′′-terpyridine (terpy) and three tricyano­methanide ligands in a distorted octa­hedral geometry. The Ni^II atoms are linked to each other, forming an infinite chain parallel to (10). π–π Stacking inter­actions of terpy mol­ecules between adjacent chains (centroid–centroid distance = 3.785 Å), along with weak inter­molecular C—H⋯N hydrogen bonds involving the uncoordinated terminal N atoms of the tricyanomethanide ions and the terpyridine H atoms, result in the formation of a three-dimensional network structure.