Group-IA metals cations

Electrochemical Group IA Metal Cation Dependence of Quinone and Nitroaromatic Crown Ether Macrocycles... 

Compound Group IA metal cation (1 equivalent added) AE (V)° ( complex fn ) Binding enhancement (KrfKi) calculated from Eq. (1) ... 

Fast atom bombardment mass spectrometry (FABMS) has been used to investigate the selectivity of monocyclic crown ethers for Group IA metal cations in competition experiments (56). We applied this semiquantitative technique for the first time to bis crown ethers (51, 53) and observed that (7) and (8) in competition experiments with Li +, Na+, K+, and Cs+ exhibited exclusive selectivity for K+ (Fig. 9). Ligands (9) and (10) however displayed no preference for any particular alkali metal cation. 

The cryptand (33) containing three ferrocene redox centers (78) has been prepared by our group via the synthetic pathway shown in Scheme 13. Although electrochemically insensitive to Group IA metal cations, this cryptand does electrochemically recognize Zn2+ and forms an isola-ble 2Zn2t (33) bimetallic complex. 

The sulfides of the group IIA metals generally have the sodium chloride structure, but those of the group IA metals have the antifluorite structure because the ratio of anions to cations is 2. Solutions of the sulfides are basic as a result of the hydrolysis reaction... 

This ligand forms stable complexes known as cryptands (and it is often abbreviated as crypt in writing formulas) with cations of the group IA metals. More recently, the ligand known as cryptand has been used instead of ethylenediamine. This ligand has the molecular structure... 

All of the Group IA and IIA metals form sulfides, some of which are used rather extensively. The sulfides of Group IIA metals consist of M2+ and S2 ions arranged in the sodium chloride type lattice (see Chapter 3). The compounds of the Group IA metals consist of M+ and S2, but as a result of there being twice as many cations as anions, the structure is of the antifluorite type (see Chapter 3). The sulfide ion is a base so there is extensive hydrolysis in solutions of the sulfides, and the solutions are basic ... 

Group IA metals lose one electron to form cations with noble gas configurations. 

The elements that form only one cation are the alkali metals (group IA), the alkaline earth metals (group IIA), zinc, cadmium, aluminum, and most often silver. The charge on the ions that these elements form in their compounds is always equal to their periodic table group number (or group number minus 10 in the newest labeling system in the periodic table). 

A. Group IA, IIA Metal Cations by Organic Redox-Active Macrocycles... 

We have recently prepared a new chromophoric and redox-responsive ionophore (4) containing a tricyanovinyl redox-active moiety (35) (Scheme 2). Electronic absorption spectra of (4) exhibit hypochromic shifts on binding Group IA and IIA metal cations and cyclic voltamme-tric electrochemical investigations reveal that (4) electrochemically recognizes Na+ and K+ guest cations, resulting in one-wave CV shifts of the tricyanovinyl reduction wave (80 and 20 mV, respectively) to more anodic potentials. 

Related copper(II) phthalocyanines substituted with crown ether groups have been reported (83,84) and shown to form discotic mesopha-ses and ion channels for alkali metal cations (85). Although polymetallic Group IA salts have been isolated, no electrochemical studies on these systems were described. 

Solid perxenate (Xe064-) salts can be obtained that contain cations of Group IA and IIA metals. The Xe064- ion has a very weak conjugate acid (HXeOe3-) so the hydrolysis reactions... 

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