Nuclear magnetic resonance studies of sodium ion complexes with several crown ethers in binary acetonitrile-dimethylsulfoxide mixtures

Ligand‐Exchange Processes on Solvated Lithium Cations: DMSO and Water/DMSO Mixtures

“…DMSO is a solvent of high solvating ability (DN = 29.8), and it can strongly compete with ligands such as crown ethers or cryptands for alkali-metal ion coordination. [28] A variety of theoretical and experimental studies on liquid DMSO, [30][31][32][33][34] water/DMSO mixtures, [35][36][37][38][39][40] DMSO/nonaqueous electrolyte solutions [41,42] and solutions of biomolecules in DMSO [43][44][45] have been performed in recent years to understand the physical properties of DMSO solutions. Solutions of alkalimetal ions, mostly Li + , in DMSO have also been investigated experimentally [46][47][48][49] and theoretically, [41,[50][51][52][53] as well as in water/ DMSO mixtures [54][55][56] and in other solvent combinations.…”

“…This property has also been confirmed by various studies of stability constants of alkali-metal complexes. [28] It is well-known that the solvating ability of the solvent, as expressed by the Guttmann donor number (DN [29] ) plays a fundamental role in different complexation reactions. DMSO is a solvent of high solvating ability (DN = 29.8), and it can strongly compete with ligands such as crown ethers or cryptands for alkali-metal ion coordination.…”

A comparison of complexation of Li+ ion with macrocyclic ligands 15-crown-5 and 12-crown-4 in binary nitromethane–acetonitrile mixtures by using lithium-7 NMR technique and ab initio calculation

“…When both 1:1 and 2:1 (crown:lithium) complexation occur in solution, the free crown concentration, [Crown], can be obtained from Eq. (2) [17]:…”

“…In general, complex stability decreases with increasing amounts of acetonitrile in the solvent mixture. It is well known that the solvating ability of the solvent, as expressed by the Gutmann donor number [29] plays a key role in different complexation reactions [3,4,6,[11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Acetonitrile and nitromethane are solvents of similar dielectric constants (i.e., ε AN = 37.5 and ε NM = 35.6) but of quite different donor numbers (i.e., DN AN = 14.1 and DN NM = 2.7) [29].…”

“…In the past two decades, we have employed NMR technique to investigate the thermodynamics [4,12,[14][15][16][17] and exchange kinetics of a number of metal ion-macrocycle complexes in different nonaqueous and mixed solvents [11,16,[18][19][20][21][22].…”