Stabilization of interpenetrating cluster-based frameworks promoted by N-HX hydrogen bonds synthesis, structures and properties of {[Cd(NH3)(4)](3)[Re3Mo3Se8(CN)(6)]}X (X = Cl, Br and I)

International audienceControl of covalent coordination polymer structures using non-covalent interactions is a promising way for obtaining functional materials by self-assembly in solution. Here we report the crucial role of halide anions in the formation of interpenetrating frameworks based on cyanometalate clusters. It was found that the interaction of [Re3Mo3Se8(CN)(6)](5-) cluster anions and Cd2+ cations in aqueous ammonia led to the formation of the 1D polymeric compound {[Cd(NH3)(5)](2)[Cd(NH3)(4)](3)[Re3Mo3Se8(CN)(6)](2)}5H(2)O (1). Compound 1 is unstable outside the mother liquor due to the rapid loss of NH3 and H2O molecules. Addition of KX (X = Cl, Br, I) to the reaction mixture led to selective formation of 3D framework compounds {[Cd(NH3)(4)](3)[Re3Mo3Se8(CN)(6)]}X (2-4 for X = Cl, Br, I, respectively) stabilized by N-HX hydrogen bonding. Compounds 2-4 demonstrate high thermal stability as well as reversible loss of ammonia and reversible oxidation in the solid state

Synthesis, crystal structure, and thermal stability of ionic cluster compounds (<i>phen</i>H)₄[Re₄Q₄(CN)₁₂]·<i>n</i>H₂O (Q = S, Se, <i>n</i> = 6; Q = Te, <i>n</i> = 10)

<div><p>Three new salts of tetrahedral rhenium chalcocyanide cluster anions [Re₄Q₄(CN)₁₂]⁴⁻ (Q = S, Se, Te) and 1,10-phenanthroline-1-ium cations, (<i>phen</i>H)₄[Re₄S₄(CN)₁₂]·6H₂O (<b>1</b>), (<i>phen</i>H)₄[Re₄Se₄(CN)₁₂]·6H₂O (<b>2</b>), and (<i>phen</i>H)₄[Re₄Te₄(CN)₁₂]·10H₂O (<b>3</b>), have been synthesized by reactions of K₄[Re₄Q₄(CN)₁₂]·<i>n</i>H₂O with 1,10-phenanthroline in the presence of Nd³⁺ in an acidic aqueous medium (pH 4). <b>1</b> and <b>2</b> exhibit similar 2-D layered supramolecular architectures based on hydrogen bonds between water molecules, CN-groups of cluster anions, and <i>phen</i>H⁺ cations. The latter are involved in <i>π</i>–<i>π</i> and C–H⋯<i>π</i> stacking interactions, connecting the adjacent layers with each other. Complex <b>3</b> demonstrates a 3-D framework based on hydrogen bonds between water molecules and CN-groups, <i>π</i>–<i>π</i> and C–H⋯<i>π</i> interactions. Notably short O···Te contacts of 3.40 and 3.50 Å are found in the structure of <b>3</b>. The thermal properties of <b>1–3</b> have been investigated by TG-DTG.</p></div

Coordination Polymers Based on Rhenium Octahedral Chalcocyanide Cluster Anions and Ag+ Cations with Bipyridine Analogs

A series of six coordination polymers based on octahedral cluster anions [Re6Q8(CN)6]4&minus; (Q = S or Se) and Ag+ cations coordinated by bipyridine analogs were synthesized under solvothermal conditions. Their structures have been characterized by single crystal X-ray diffraction. Compounds 1 and 2 described by the general formula [{Ag(phen)}4Re6Q8(CN)6] (Q = Se (1), S (2); phen = 1,10-phenanthroline) exhibit layered structures assembled into a supramolecular network by CH&hellip;&pi; contacts. At the same time, compounds [{Ag(bipym)}2Ag2Re6Se8(CN)6] (bipym = 2,2&prime;-bipyrimidine) (3), [{Ag2(bipy)}Ag2Re6Se8(CN)6]&middot;CH3CN (bipy = 4,4&prime;-bipyridine) (4) and [{Ag(dpbp)}4Re6Q8(CN)6]&middot;2H2O&middot;2CH3CN (Q = Se (5), S (6); dpbp = 4,4&prime;-Di(4-pyridyl)biphenyl)) evince framework structures. In 1, 2, 5 and 6 weak Ag&#8943;Ag interactions are observed. All the compounds show luminescence in the red region. The luminescence quantum yields and lifetimes were found to be notably higher than those for most of the coordination polymers based on the octahedral rhenium cluster complexes

Octahedral Rhenium Cluster Complexes with 1,2-Bis(4-pyridyl)ethylene and 1,3-Bis(4-pyridyl)propane as Apical Ligands

A series of eight new octahedral rhenium cluster complexes with the general formula trans-[{Re6Q8}L4X2] (Q = S or Se; L = 1,2-Bis(4-pyridyl)ethylene (bpe) or 1,3-Bis(4-pyridyl)propane (bpp); X = Cl or Br) was synthesized and investigated. While bpe is a ligand with a conjugated aromatic system, bpp represents a molecule of opposite type and has independent aromatic systems of the two pyridine rings. It was shown that this difference in the electronic structure of the ligands has a fundamental effect on the electronic structure, electrochemical and luminescent properties of the corresponding cluster complexes. Specifically, the [{Re6Q8}(bpe)4X2] complexes in solutions show multiple quasi-reversible electrochemical transitions associated with reduction of the organic ligands. At the same time, the trans-[{Re6Q8}(bpp)4X2] complexes show multielectron quasi-irreversible reduction processes, which correlate with the mixed character of the lowest unoccupied molecular orbitals of these complexes. All the obtained new compounds exhibit red photoluminescence. The photophysical parameters (emission lifetimes and quantum yields) measured for the bpp complexes exceed those revealed for bpe complexes by more than an order of magnitude

Thermally Controlled Synthesis of Octahedral Rhenium Clusters with 4,4′-Bipyridine and CN⁻ Apical Ligands

The selective preparation, structural and spectroscopic study of two new rhenium cluster complexes trans-[Re6S8(bpy)4(CN)2] and trans-[Re6S8(bpy)2(CN)4]2− (bpy = 4,4′-bipyridine) obtained by reactions of corresponding hexarhenium cyanohalides with molten bpy are reported. The complexes were crystallized as solvates, displaying supramolecular structures based on cluster units linked by numerous weak interactions with bpy molecules. The molecular compound trans-[Re6S8(bpy)4(CN)2] (1) is insoluble in water and common organic solvents, while the ionic compound trans-Cs1.7K0.3[Re6S8(bpy)2(CN)4] (2) is somewhat soluble in DMSO, DMF and N-methylpyrrolidone. The presence of the redox-active ligand bpy leads to the occurrence of multi-electron reduction transitions in a solution of 2 at moderate potential values. The ambidentate CN− ligand is the secondary functional group, which has potential for the synthesis of coordination polymers based on the new cluster complexes. In addition, both new compounds show a weak red luminescence, which is characteristic of complexes with a {Re6S8}2+ cluster core

Thermally Controlled Synthesis of Octahedral Rhenium Clusters with 4,4′-Bipyridine and CN− Apical Ligands

The selective preparation, structural and spectroscopic study of two new rhenium cluster complexes trans-[Re6S8(bpy)4(CN)2] and trans-[Re6S8(bpy)2(CN)4]2− (bpy = 4,4′-bipyridine) obtained by reactions of corresponding hexarhenium cyanohalides with molten bpy are reported. The complexes were crystallized as solvates, displaying supramolecular structures based on cluster units linked by numerous weak interactions with bpy molecules. The molecular compound trans-[Re6S8(bpy)4(CN)2] (1) is insoluble in water and common organic solvents, while the ionic compound trans-Cs1.7K0.3[Re6S8(bpy)2(CN)4] (2) is somewhat soluble in DMSO, DMF and N-methylpyrrolidone. The presence of the redox-active ligand bpy leads to the occurrence of multi-electron reduction transitions in a solution of 2 at moderate potential values. The ambidentate CN− ligand is the secondary functional group, which has potential for the synthesis of coordination polymers based on the new cluster complexes. In addition, both new compounds show a weak red luminescence, which is characteristic of complexes with a {Re6S8}2+ cluster core