Redox-Active Porous Coordination Polymers Prepared by Trinuclear Heterometallic Pivalate Linking with the Redox-Active Nickel(II) Complex: Synthesis, Structure, Magnetic and Redox Properties, and Electrocatalytic Activity in Organic Compound Dehalogenation in Heterogeneous Medium

Abstract

International audienceLinking of the trinuclear pivalate fragment Fe2CoO(Piv)6 by the redox-active bridge Ni(L)2 (compound 1; LH is Schiff base from hydrazide of 4-pyridinecarboxylic acid and 2-pyridinecarbaldehyde, Piv– = pivalate) led to formation of a new porous coordination polymer (PCP) {Fe2CoO(Piv)6}{Ni(L)2}1.5 (2). X-ray structures of 1 and 2 were determined. A crystal lattice of compound 2 is built from stacked 2D layers; the Ni(L)2 units can be considered as bridges, which bind two Fe2CoO(Piv)6 units. In desolvated form, 2 possesses a porous crystal lattice (SBET = 50 m2 g–1, VDR = 0.017 cm3 g–1 estimated from N2 sorption at 78 K). At 298 K, 2 absorbed a significant quantity of methanol (up to 0.3 cm3 g–1) and chloroform. Temperature dependence of molar magnetic susceptibility of 2 could be fitted as superposition of χMT of Fe2CoO(Piv)6 and Ni(L)2 units, possible interactions between them were taken into account using molecular field model. In turn, magnetic properties of the Fe2CoO(Piv)6 unit were fitted using two models, one of which directly took into account a spin–orbit coupling of CoII, and in the second model the spin–orbit coupling of CoII was approximated as zero-field splitting. Electrochemical and electrocatalytic properties of 2 were studied by cyclic voltammetry in suspension and compared with electrochemical and electrocatalytic properties of a soluble analogue 1. A catalytic effect was determined by analysis of the catalytic current dependency on concentrations of the substrate. Compound 1 possessed electrocatalytic activity in organic halide dehalogenation, and such activity was preserved for the Ni(L)2 units, incorporated into the framework of 2. In addition, a new property occurred in the case of 2: the catalytic activity of PCP depended on its sorption capacity with respect to the substrate. In contrast to homogeneous catalysts, usage of solid PCPs may allow selectivity due to porous structure and simplify separation of product

Versatile Reactivity of MnII Complexes in Reactions with N-Donor Heterocycles: Metamorphosis of Labile Homometallic Pivalates vs. Assembling of Endurable Heterometallic Acetates

“…In contrast, 11′ absorbed significant quantities of methanol and ethanol at 298 K (Figure 14). Such a difference between absorption of gases and alcohols can be caused by expansion of crystal lattice of 11′ upon interaction with methanol and ethanol, similarly to reported gate-opening phenomena [77] and previously reported cases of alcohol absorption by coordination polymers [18]. Both in the cases of methanol and ethanol, the sorption capacity gradually increased to ca.…”

“…Polynuclear coordination compounds of transition metals are widely used as catalysts in various reactions [1][2][3][4][5], as starting materials for the preparation of nanosized oxides or metals [6][7][8], as well as the basis for the creation of new magnetic materials [9][10][11][12][13] and coordination polymers with remarkable properties [14][15][16][17][18][19][20]. In the majority of these applications the stability or reactivity of the polynuclear core play an important role.…”

Exchange Interactions in Cobalt(II) and Nickel(II) Complexes Containing M4(μ3-OH)2 Metal Cores with Distorted Rhombic Topology

“…The combination of various useful physical properties in a single molecule make such compounds promising for use in multifunctional materials [5]. A current problem in physical inorganic chemistry is the development of methods for introducing fragments into polynuclear complexes with desired physical or physicochemical characteristics such as a given redox-potential [6]. Ferrocenyl, whose redox activity is well known [7], may be considered as such a fragment.…”

Heterometallic coordination polymers as heterogeneous electrocatalysts

“…7). 102 They prepared a mononuclear nickel(II) complex with a Schiff base ligand that was derived from the hydrazine of 4-pyridinecarboxylic acid and 2-pyridinecarbaldehyde to act as a N-donating metalloligand. Since electrocatalytic current is commonly much higher than the current of a standard redox process, it is often used as the signal for molecular sensors working in solution.…”