Activation of CO2 by tBuZnOH species: efficient routes to novel nanomaterials based on zinc carbonates

Abstract

We report on the activation of CO2 by the well-defined alkylzinc hydroxide (tBuZnOH)6 in the absence and presence of tBu2Zn as an external proton acceptor. The slight modifications in reaction systems involving organozinc precursors enable control of the reaction products with high selectivity leading to the isolation of the mesoporous solid based on ZnCO3 nanoparticles or an unprecedented discrete alkylzinc carbonate [(tBuZn)2(μ5-CO3)]6 cluster with the Zn-C bond intact, respectively.

Experimental and Computational Insights into Carbon Dioxide Fixation by RZnOH Species

“…A gel-like, insoluble substance containing ZnCO 3 NPs was recovered from the NMR tube after the reaction ended. [7] To test the effect of py-Me as a strong Lewis base on the reaction between RZnOH species and CO 2 , we examined the reactivity of the py-Me adduct 3 towards CO 2 in [D 8 ]THF at 298 K. Again, significant broadening of ZnOH signals was observed (Figure 2 b and Figure S6 in the Supporting Information); however, resonances attributed to [tBuZn(HCO 3 )] emerged shortly (after around 10 min) and simultaneously signals belonging to 1 (d = 1.05 and 4.49 ppm) decreased. [14] Strikingly, for the 3/CO 2 system, we essentially did not observe any signals of isobutane during the first 90 min of the reaction.…”

“…These preliminary investigations provided the first example of a structurally characterized alkylzinc hydroxide, tBuZnOH (1), [6] which, in the presence of CO 2 , can form different nanomaterials based on CO 3 2À as a templating ion, for example, ZnCO 3 nanoparticles (NPs) or discrete alkylzinc carbonate cluster 2 (Scheme 1 b). [7] Moreover, the introduction of an auxiliary ligand, L, to the RZnOH system, [8] followed by the reaction with CO 2 , led to the formation of the nanosized cluster [(L 2 Zn) 6 (ZnCO 3 ) 4 ]…”

“…We selected 1 as a model system for CO 2 fixation. [7,9] In particular, we were interested in 1) the solution and solid-state behavior of 1 in the presence of Lewis bases, namely, THF and 4-methylpyridine (py-Me); 2) the sequence of elementary steps of the reaction between 1 and CO 2 ; and 3) the effect of a Lewis base and an excess of tBu 2 Zn on the reaction course.…”

Permanent Porosity Derived From the Self‐Assembly of Highly Luminescent Molecular Zinc Carbonate Nanoclusters

“…[12a, 13] The rational design and preparation of NPMs showing extrinsic porosity based on molecular metal complexes is highly challenging and few examples have been reported. [14] We have demonstrated previously that alkylzinc hydroxides RZnOH can be efficiently transformed into multinuclear alkyzinc carbonate nanoclusters [15] or nanomaterials, such as discrete nanoparticulate zinc carbonate aerogels [15] and ZnO nanoparticles. [16] As shown in Scheme 1 a, the reactivity of the RZnOH species can be rationalized in terms of the presence of both a proton-reactive Zn À C bond and CO 2 -reactive Zn À OH groups.…”

“…[19] The presence of the carbonate group in WUT-1 was confirmed by a resonance at 165.3 ppm in the CP-MAS 13 C NMR spectrum as well as by a strong band at 1510 cm À1 , which is characteristic for a carbonate ligand in the IR spectrum (see the Supporting Information). [15] The X-ray data for the as-synthesized single crystals of WUT-1 show residual peaks derived from disordered PhMe molecules (see the Supporting Information). However, this residual amount of solvent can be removed under vacuum (see below) providing desolvated single crystals of WUT-1 a with the preserved crystal structure (Table S2).…”