Liquid-assisted solid-state reaction: assembly of (6,3) and (10,3) hydrogen-bonded networks based on [M(Hbiim)3] by oxidation of [M(H2biim)3]2+ complexes in the presence of acetate anions

Abstract

Two complexes [Ru(Hbiim) 3 ] (1) and [Co(Hbiim) 3 ]$3H 2 O (2) (H 2 biim ¼ 2,2 0 -biimidazole) were synthesized quantitatively and rapidly via a ''liquid-assisted'' solid-state reaction approach. The reaction occurs within minutes of grinding together [Ru(H 2 biim) 3 ](PF 6 ) 2 or [Co(H 2 biim) 3 ]Cl 2 and NH 4 OAc with a few drops of H 2 O 2 as an oxidant and solvent, concomitant with colour changes. The structures of the compounds obtained from the solid-state reaction were confirmed by comparison of their PXRD patterns with simulations based on their single crystal structures. Complex 1 is a 3-fold interpenetrating three-dimensional hydrogen bonded polycatenate network based on a (6,3) net, complex 2 is a double-layer network linked by the lattice water molecules and the Hbiim ligands via hydrogen bonds. For comparison with the solid-state reaction, control reactions were also carried out in solution. Complex 1 was also afforded from the solution reaction. However, a new phase [Co(Hbiim) 3 ]$0.5EtOH (3) was obtained from solution, rather than 2, although it also crystallized from an identical solution of EtOH-water. Complex 3 is a 4-fold interpenetrating three-dimensional hydrogen bonded polycatenate network based on a (10,3)-b net. Interesting, the [M(H 2 biim) 3 ] 2+ (M ¼ Ru and Co) species can be oxidized to the corresponding [M(Hbiim) 3 ] species by oxygen in the presence of acetate anions, which play a determined role in the redox reaction. The deprotonation of the [M(H 2 biim) 3 ] 2+ species triggered by the acetate anions greatly increases the electron density at the M(II) center and shifts the oxidation potentials of M(II) complex to a less positive value. This may provide an effective approach for the generation of high status metal complexes via supramolecular interactions.

Synchronized Collective Proton-Assisted Electron Transfer in Solid State by Hydrogen-Bonding Ru(II)/Ru(III) Mixed-Valence Molecular Crystals

“…Figure a shows a perspective view along the c axis of the crystal structure of 1 . A nanoporous crystal with 1D channels is formed by using the crystallization solvent as a template, whereas the same [Ru III (Hbim) 3 ] molecules were previously reported to form twofold interpenetrated crystals with both (6,6) sheets and 3D (10,3)- b networks without a nanoporous channel as polymorphism by the different crystallization solvent. First, [Ru III (Hbim) 3 ] forms the 1D nanoporous crystal of 1 by stacking the honeycomb sheet structures and adjusting the porous cavities, constructed from alternating complementary N–H···N H-bonds between the Δ and Λ optical isomers (N(4)···N(2) = 2.773(4) Å, N(6)···N(6)* = 2.748(6) Å, N(10)···N(8) = 2.708(4) Å, N(12)···N(12)* = 2.717(7) Å, *­( x , − y + 1, z )).…”

“…A nanoporous crystal with 1D channels is formed by using the crystallization solvent as a template, whereas the same [Ru III (Hbim) 3 ] molecules were previously reported to form twofold interpenetrated crystals with both (6,6) sheets 42 and 3D (10,3)-b networks without a nanoporous channel 33 as polymorphism by the different crystallization solvent. but their positions in the pore cannot be determined due to heavy disorder.…”

Clean and Efficient Synthesis Using Mechanochemistry: Coordination Polymers, Metal-Organic Frameworks and Metallodrugs

“…The ILAG methodology appears to be applicable beyond reactions of zinc oxide, as demonstrated by its recent use to enable the mechanochemical oxidation of cobalt and ruthenium complexes. 68 We have expanded the use of ILAG for the synthesis of zeolitic imidazolate frameworks (ZIFs), 69a a family of porous MOFs which exploit a combination of tetrahedral metal ions (e.g. Zn 2+ , Co 2+ ) 70 and azolate anions 71 to obtain porous metal-organic topologies analogous to those of zeolites.…”

Alternative Technologies That Facilitate Access to Discrete Metal Complexes

“…Although the synthesis of many iron complexes was described by using mechanochemistry, to date only one publication reported the mechanosynthesis of a ruthenium complex. Thus, after manual grinding in a mortar and pestle of 160 The reaction could also be performed at room temperature in solution, but the complex was isolated with a low yield of 30%.…”