Alkali metal ion complexes

Tummler, B. Maass, G. Weber, E. Wehner, W., Voegtle, F., (1977) Noncyclic crown-type polyethers, pyridinophane cryptands, and their alkali metal ion complexes Synthesis, complex stability and kinetics J. Am. Chem. Soc. 99, 4683-4689. 

Tummler B et al (1979) Open-chain polyethers - influence of aromatic donor end groups on thermodynamics and kinetics of alkali-metal ion complex-formation. J Am Chem Soc 101 2588-2598... 

In contrast to the behavior of 68, an efficient chemosensor for Mg2+,123 compound 107 has been shown to be a potential chemosensor for Hg2+.157 Ligand 107 forms stable 1 1 complexes with Hg 2+, Cu2+, Cd2+, Zn2+, Ni2+, and Mg2+ in methanol-water (1 1 vol vol). Much lower association constants (log Ka < 2.5) are observed with the other alkaline earth ions, whereas no complexation is detected (log < 1.5) for alkali metal ions. Complexes with Cu2+ and Ni2+ are not luminescent as... 

Keywords Silsesquioxanes / Alkali metal ion complexes / Extraction constants... 

Fig. 9. Absorption spectra of alkali metal ion complexes with murexide 12...

Becher <90JA3709> has studied by californium-252 plasma desorption mass spectrometry the alkali metal ion complexation of a crown ether containing two pyrazole subunits. Rebek <93RTC330> prepared one of his famous molecular clefts with two 3-/-butylpyrazol-l-yl substituents. 

Table 4. Stability constants of alkali metal ion complexes...

The vibrational spectra of diethyl ether complexes with MgBrj and MgL have been assigned completely p(MgO) are 390-300 cm" . The solid-state Raman spectra of 1 1 and 1 2 adducts of 1,4-dioxane with metal halides show that the ligand is bridging between metals in the chair conformation. Infrared spectra of alkali-metal ions complexed by cyclic polyethers have been reported. "... 

The conformation of uncomplexed antamanide is entirely different from that of the alkali metal ion complexes. Not only is the cyclic backbone elongated and flattened, but sequences 4,5,6 and 9,10,1 turn inside-out so that the... 

Given the structural analogy with the crown ethers, the calixarenes were alkylated to produce ether ligands at the phenolic face. These molecules complex various cations including alkali metals ions. Complexation may take place... 

Ramakrishnan reported donor-acceptor polymers that contain three folding elements alternating aromatic donors and acceptors, linked by oligo(oxyethylene) groups [43]. Folding was driven by the solvophobic effect, or by alkali-metal ion complexation, and characterized by the upfield shift of the NMR signals of aromatic protons shifts or by substantial changes in the UV-Vis spectra. 

Cyclic oligomers of (EtAsO) were found to act as polydentate ligands for alkali metal ions complexes [Na (EtAsO)4 2] SCN (10) and [K (EtAsO)5 2]SCN (11) were characterised. ... 

The extensive studies on the binding-free energies of the alkali metal ion complexes for the different stereoisomers, cone, partial cone, and 1,3-alternate, revealed a strong dependence of the binding efficiency upon calixarene conformation, although all the calix-crown-5 are selective... 

The cavity of a crown efher is a polar region, and fhe unshared pairs of electrons on the oxygen atoms lining the cavity provide effective solvation for alkali metal ions. The outer surface of the crown is nonpolar and hydrocarbon-like thus, crown ethers and their alkali metal ion complexes dissolve readily in nonpolar organic solvents. 

Observations of alkali-metal ion adducts of the type [M+Li]+ [M+Na]+ etc. are common in the desorption ionization (DI) mass spectra of a variety of polar molecules. In fact, alkali-metal ion association reactions are observed with FD ionization, FAB ionization, Cf plasma desorption (PD), secondary ion mass spectrometry (SIMS), MALDI, and ESI. Ion yields can be greatly enhanced by addition of alkali-metal salts to the sample. Particularly for the MALDI analysis of synthetic polymers, metal cations are often intentionally added to enhance signals. A qualitative description of the current understanding of formation mechanism of alkali-metal ion complexes from the condensed phase was presented [75]. Knowledge of the ionization mechanisms is important and helpful from the perspective of increasing the analytical utility of the method. 

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