Homo‐ and Heteropentanuclear Coordination Compounds with T_d Symmetry – the Solid State Structures of [MZn₄(L)₄(L′)₆] (M = Co^II or Zn; L = chloride or acac; L′ = 1,2,3‐benzotriazolate)

Abstract

The syntheses of homo-and heteropentanuclear coordination compounds with the molecular formulae [MZn 4 (L) 4 (LЈ) 6 ] (M ϭ Co II or Zn; L ϭ chloride or acac; LЈ ϭ 1,2,3-benzotriazolate) are reported. These compounds display a highly symmetric coordination unit consisting of a central metal ion (M ϭ Co II or Zn) which is octahedrally coordinated by 6 tridentate benzotriazolatetype ligands via their N(2) donor atom. The benzotriazolate ligands span the edges of an imaginary tetrahedron thus providing four coordination sites at the corners of the tetrahedron, which are then filled by four zinc ions. The coordination shell of the latter are completed by bidentate acetylacetonate (acac) ligands or by chloride anions, respectively. The solid state structures of two homopentanuclear metal complexes, namely [Zn 5 (acac) 4 (bta) 6 ] · 4C 6 H 12 (1) (acacH ϭ acetylacetone; btaH ϭ 1,2,3-benzotriazole), and [Zn 5 Cl 4 (Me 2 bta) 6 ] · 2DMF (2) (Me 2 btaH ϭ 5,6-dimethyl-1,2,3benzotriazole) were determined by single crystal X-ray structure analysis. The heteropentanuclear metal complex [Co II Zn 4 Cl 4 (Me 2 bta) 6 ] · 2DMF (3) is isostructural with compound

Nonanuclear Coordination Compounds Featuring {M9L12}6+ Cores (M = NiII, CoII, or ZnII; L = 1,2,3‐Benzotriazolate)

“…Focusing our summary on coordination compounds of µ 3 -benzotriazolates with divalent metal ions, a range of pentanuclear metal complexes of the formula [M 5 (L) 4-x (OH) x (LЈ) 6 (H 2 O) 4x ] (where M = Cu, Ni, Zn; LЈ = bta or Me 2 bta; L = β-diketonate, x = 0, 1) were described in the literature. [6,9] Moreover, a mixedvalent pentanuclear copper [7] and a nonanuclear nickel [8] benzotriazolate complex have been reported. Magnetic susceptibility studies performed on both the pentanuclear copper and the nonanuclear nickel complexes show antiferromagnetic interactions.…”

“…[6][7][8] Most of these complexes are prepared in solution employing metal(II) β-diketonates as precursors, thus taking advantage of the proton transfer between metal(II) β-diketonates and benzotriazole ligands, which subsequently leads to partial replacement of β-diketonato ligands by deprotonated benzotriazoles. Recently, we reported T d -symmetrical pentanuclear metal complexes of the type [MЈZn 4 Cl 4 (L 6 )], [9] where MЈ = Zn or Co II , and L represents a 1,2,3-benzotriazolate ligand. For the synthesis of these compounds metal precursors and ligands were combined at the theoretical stoichiometric ratio in the presence of an auxiliary base such as lutidine.…”

“…Different coordination sites in the T d -symmetric pentanuclear coordination compounds of type [MMЈ 4 Cl 4 (bta) 6 ] (M = Co II , MЈ = Zn) as described in ref. [9] However, the homonuclear Ni, Co, and Zn compounds described in the current manuscript have all been synthesized using an excess of ligand, which acts as an auxiliary base leading to deprotonation of the acidic protons of coordinated ligands. Employing this strategy, we have been able to prepare three novel compounds, namely [Ni 9 (bta) 12 (2), and [Zn 9 (Me 2 bta) 12 (CH 3 COO) 6 ]·3DMF (3), which were characterized by single-crystal X-ray structure analysis, UV/Vis spectroscopy as well as temperature-dependent magnetic susceptibility measurements.…”

Elucidating Gating Effects for Hydrogen Sorption in MFU‐4‐Type Triazolate‐Based Metal–Organic Frameworks Featuring Different Pore Sizes

“…[10] Since the particular SBU of MFU-1 seems to be limited to the presence of a {Co 4 O} core, we have developed a modular MOF family (MFU-4), [11] which is based on Kuratowski-type pentanuclear SBUs of the general formula [M II Zn 4 X 4 (L 6 )] (Figure 1, right). These feature a central metal ion coordinated to six triazolate ligands (L) that span a Cartesian system and can either be assembled into discrete coordination compounds [12] or into porous cubic frameworks. [11] The central metal ion in the octahedral coordination environment can be varied [12] giving the opportunity of potentially obtaining redox-active SBUs that are also Lewis acidic, with chemical properties that can be finetuned by selecting appropriate metal ions.…”

“…These feature a central metal ion coordinated to six triazolate ligands (L) that span a Cartesian system and can either be assembled into discrete coordination compounds [12] or into porous cubic frameworks. [11] The central metal ion in the octahedral coordination environment can be varied [12] giving the opportunity of potentially obtaining redox-active SBUs that are also Lewis acidic, with chemical properties that can be finetuned by selecting appropriate metal ions. Changing the Zn 2 + ions in tetrahedral positions to other transition-metal ions could improve hydrogen-sorption properties.…”