Conversion between Doubly and Triply Carboxylate Bridged Bis(ethylzinc) Complexes and Formation of the (μ-Oxo)tetrazinc Carboxylate [Zn₄O(Ar^TolCO₂)₆]

Abstract

Ethylzinc 2,6-bis(p-tolyl)benzoate converts between two forms in solution. Through NMR spectroscopic techniques and X-ray crystallography, the species in equilibrium were identified as [Zn2(ArTolCO2)2(Et)2(THF)2] (1), [Zn2(ArTolCO2)3(Et)(THF)] (2), and diethylzinc (ArTol = 2,6-bis(p-tolyl)phenyl). The equilibrium provides a model for understanding the speciation between doubly and triply m-terphenylcarboxylate bridged diiron(II) and mononuclear iron(II) complexes. Evidence is presented for the occurrence of coordinatively unsaturated trigonal zinc species in solution. Both 1 and 2 decompose in air to form the T-symmetric oxozinc carboxylate [Zn4O(ArTolCO2)6] (3).

Structural Diversity of Ethylzinc Carboxylates

“…For example, Minier and Lippard reported on a dynamic conversion in solution between [Zn 2 (Ar Tol CO 2 ) 2 (Et) 2 (THF) 2 ] and [Zn 2 (Ar Tol CO 2 ) 3 (Et)(THF)] with doubly and triply bridged carboxylates. 13 However, thorough inspection of the data implies inconsistencies in presented equilibrium and does not clearly prove the interconversion between the two species. The importance of a donor solvent is particularly evident in the ethylzinc acetate derivative.…”

“…The structure is also influenced by the presence of a donor solvent in the reaction medium. For example, Minier and Lippard reported on a dynamic conversion in solution between [Zn 2 (Ar Tol CO 2 ) 2 ­(Et) 2 ­(THF) 2 ] and [Zn 2 (Ar Tol CO 2 ) 3 ­(Et)­(THF)] with doubly and triply bridged carboxylates . However, thorough inspection of the data implies inconsistencies in presented equilibrium and does not clearly prove the interconversion between the two species.…”

Novel phosphinate‐containing zinc polyacrylate and its utilization as flame retardant for polyamides

“…To analyze this structural behavior for component 1‐A diffusion‐ordered NMR spectroscopy (DOSY) was performed on the monomer solution of 1‐A in DMAc (Figure ) as well as on complex 3 (Figure ) and pure ZDA (Figure ) in comparison. This method was already used to observe the structure of various zinc carboxylates and their interaction with coordinating solvents . All signals of 1‐A align at the same diffusion constant D of 6.13 × 10 −6 m 2 s −1 and thus at one hydrodynamic radius.…”

“…This method was already used to observe the structure of various zinc carboxylates and their interaction with coordinating solvents. 35 All signals of 1-A align at the same diffusion constant D of 6.13 × 10 −6 m 2 s −1 and thus at one hydrodynamic radius. This shows that both carboxylate functionalities of the acrylate and DOPO-propionate are coordinated to the zinc ion and thus that the desired structure of the molecule was formed.…”

Polynuclear alkoxy–zinc complexes of bowl-shaped macrocycles and their use in the copolymerisation of cyclohexene oxide and CO2

“…Multidentate macrocycles are attractive as ligands for di-and polynuclear complexes of transition-and f-block metals as they can control both the basic coordination chemistry and the relative spatial positioning of metals within the macrocyclic framework, so providing a pre-organised chemical environment. [1][2][3][4] This ligand design strategy can deliver a diversity of physical and reaction properties in the resulting complexes leading to, for example, clustering and aggregation, [5][6][7][8][9][10][11][12][13][14] catalytic activity, [15][16][17][18][19][20][21][22][23][24][25][26][27][28] molecular magnetism, 29 allosteric constructs, 30,31 and molecular sensing. [32][33][34][35] We have been studying macrocycles in which two donor compartments comprising two dipyrromethane and two Schiff-base nitrogen donors (i.e.…”