K+···Cπ and K+···F Non-Covalent Interactions in π-Functionalized Potassium Fluoroalkoxides

Abstract

Secondary interactions stabilize coordinatively demanding complexes of s-block metals. The structures of potassium fluoroalkoxides that, in addition to intra-and intermolecular K + ···F contacts, also exhibit K + ···C π interactions with tethered π ligands, are reported. A potassium-arene, a rare potassium-alkyne, and a potassium-olefin complex have been prepared by deprotonation of functionalized α,α-bis(trifluoromethyl)alcohols with KN(SiMe 2 R) 2 . They all feature a cuboid K 4 O 4 core with µ 3 -bridging O atoms, and multiple stabilizing K + ···F contacts in the range 2.71-3.33 Å.The potassium-arene complex shows η 2 , η 3 , and η 6 K + ···C π (arene) interactions in the range 3.35-3.47 Å. The potassium-alkyne and potassium-olefin compounds are stabilized by η 2 interactions with the unsaturated carbon-carbon bond, in the range 3.17-3.49 Å and 3.15-3.19 Å, respectively. Comparison with the parent complex devoid of a flanking π ligand illustrates the role of K + ···C π interactions.

Ligand Influence on Carbonyl Hydroboration Catalysis by Alkali Metal Hydridotriphenylborates [(L)M][HBPh3] (M=Li, Na, K)

“…[18] The Cambridge StructuralD atabase (CSD) contains more than 300 crystal structuress howing K + ···C p (arene) interactions.S uch binding forces are important in biologyf or defining protein structures, ion transportation, molecular recognition, and enzyme catalysis. [18] The Cambridge StructuralD atabase (CSD) contains more than 300 crystal structuress howing K + ···C p (arene) interactions.S uch binding forces are important in biologyf or defining protein structures, ion transportation, molecular recognition, and enzyme catalysis.…”

“…Non‐covalent M + ⋅⋅⋅C π interactions for the alkali metals, especially for the heavier congeners, are important for stabilization by coordinative saturation . The Cambridge Structural Database (CSD) contains more than 300 crystal structures showing K + ⋅⋅⋅C π (arene) interactions.…”

Kudos and Renaissance of s-Block Metal Chemistry

“…In the recent past, increasing efforts have been undertaken to develop a sophisticated chemistry of these elements [19][20][21]. The chemistry of methanediides [22] and the relevance of secondary interactions [23], discussed in this Special Issue, may be viewed as representative examples. In contrast to lithium, the heavier homologous elements, sodium and potassium as well as calcium, are globally abundant, easily available, inexpensive and of low toxicity.…”

Reactant-Induced Photoactivation of a Gold-Catalyzed Csp2-Csp Cross-Coupling Leading to Indoles

“…35 The last interaction consists in a η 1 -coordination between a carbon of the tolyl ring and the potassium cation with a distance of 3.3074 Å. 33 Conversely, one can understand the detrimental effect of 18-C-6 that would prevent the formation of this aggregate. Fig.…”