Formation of Multinuclear s‐Block Metal Systems by Enhancement of the Coordination Properties of 1,2,3‐Triazole

Abstract

The 4,5‐{Ph2(HO)C}2‐1,2,3‐triazole ligand (2) with two bulky Ph2C(HO) substituents was synthesized and used in the preparation of coordination compounds with selected group 1 metals. In the solid state, the high Lewis acidity of lithium caused the formation of di‐ and tetrametallic L2Li2thf4·2THF and L4Li4thf2(Et2O)2·2Et2O (L = monoanionic form of 2) species, while only the dimetallic derivative L2Na2thf4·2THF was observed for sodium. The larger size of potassium caused the formation of L6K6(H2O)thf2·2THF with a hexagonal drumlike inorganic core. 1H DOSY NMR spectroscopic studies confirmed the presence of multimetallic species also in solution. The molecular structures of the compounds were determined by single‐crystal X‐ray diffraction. In a comparative study, magnesium derivatives of 2 were prepared to evaluate the effect of a higher covalent character of the M–O bond leading to multimetallic polycyclic systems with up to 29 rings. Finally, the lithium compounds showed catalytic activity in the polymerization of ε‐caprolactone.

Self-Assembly of Aluminum- and Gallium-Based meso-Metallaporphyrins

“…The solvents were dried using MBraun SPS equipped with Grubb’s type columns. The 2-NH-4,5-bis­(Ph 2 (HO)­C) 2 -1,2,3-triazole ( 1 ) and [(κ 2 - N , N ′-4,5-bis­(Ph 2 (HO)­C) 2 -1,2,3-triazole)­{Li­(THF) 2 }] 2 ( 2 ) were prepared according our earlier report . All manipulations were performed under a dry and oxygen-free atmosphere (N 2 ) using Schlenk-line and glovebox techniques.…”

“…The 2-NH-4,5-bis(Ph 2 (HO)C) 2 -1,2,3-triazole (1) and [(κ 2 -N,N′-4,5-bis(Ph 2 (HO)C) 2 -1,2,3-triazole){Li(THF) 2 }] 2 (2) were prepared according our earlier report. 20 All manipulations were performed under a dry and oxygen-free atmosphere (N 2 ) using Schlenk-line and glovebox techniques. The NMR spectra were recorded on a Bruker Avance 300 spectrometer, 1 H NMR spectra were referenced to residual protons from the deuterated solvent.…”

“…19 Recently, we have reported on the preparation of coordination compounds with s-block elements based on the 4,5-(Ph 2 (HO)C) 2 -1,2,3-triazole ligand (1) that was specially designed to promote the formation of molecular metallacycles, whose structure would not be dominated by the carboxylate groups (as in the case of 1,2,3-triazole-4,5-dicarboxylic acid) because the triazole ring (pK a = 9.4) in 1 is deprotonated before the OH groups (pK a = ∼16). 20 In these complexes, the 1,2,3-triazole ring coordinates to two or three metal atoms and the coordination of the alkoxy groups to another metal fixates the triazole rings in a mutual orientation that allows their coordination to another metal. In this paper, we describe the self-assembly of different stereoisomers of molecular mesometallaporphyrins via the coordination of ligand 1 to aluminum (Figure 2).…”

Construction of Alkali‐metal‐based Imidazolecarboxylate Coordination Polymers as Efficient Catalysts for Solvent‐free Ring‐opening polymerization of ϵ‐Caprolactone

“…[14] Discrete complexes with alkali-metal ions have become a particularly attractive class of ROP catalysts over the past decade owing to their low cost and non-toxicity as well as high stereoselectivity control. [15][16][17][18][19][20] These catalysts are ion-pair complexes and the ROP process proceeds via a anionic mechanism. Of particular note are the lithium(I)-based complexes with various ligands reported by Lin [6] and Otero et al, [21,22] which were used for catalytic CL polymerization.…”

Alkali Metallosilicates: Synthesis, Structure and Evaluation in the ROP of ϵ‐Caprolactone

“…However, the potential encapsulation of trace amounts of tin in the obtained polymer limits its use for biomedical applications due to its toxicity. [31,32] As a result of our recent work on group 1 complexes with triazole ligands which efficiently initiated the ROP of ɛ-CL, [33] we extended our study to the chemistry of group 1 metallosilicates. We envisioned the use of trialkoxysilanol ( t BuO) 2 (RO)SiOH ligands, since the variation of the third alkoxy group allows fine-tuning of the steric properties and thus, of their activity in ROP of ɛ-CL.…”