Hydrogen bonding anions

Fig. 26 A typical example [Cu(Lem)2] [N03]2 of a hydrogen-bonded anion-mediated 2-D rhombic (4,4) network (atom identification as for Fig. 1 plus copper large light grey circles) [61]...

VIII. The Next Surprise Rotaxane Synthesis Mediated by a Template Based on Hydrogen-Bonded Anions... 

The triol 16 can be deprotonated according to Scheme 6. The initial step involves met-allation and this is followed by a coproportionation on addition of two further equivalents of 16. Finally, addition of an ammonium or phosphonium salt gives 36. The stability of the ion has implications for the surface chemistry of silica where similar multiply hydrogen bonded anion sites are likely to be more acidic than isolated silanol groups144. The related cubic polyanion [SigOigtOHji]6- can be prepared directly from aqueous solutions of silica and a quaternary ammonium hydroxide derivative such as [NPhMe3]OH145 146. 

Mak TCW (1985) Tfetraethylammonium acetate tetrahydrate, (C2H5)4N+CH3COO- 4H2Of a layer structure with cations sandwiched between nets of puckered polygons formed by hydrogen bonded anions and water molecules. J Inclusion Phenom 4 273 -280... 

There are two monohydrido complexes which have been prepared by the oxidative addition of hydrogen halides to [Rh P(OMe)3 5][BPh4] (equation 223). Two other monohydrido complexes having hydrogen-bonded anions have been prepared by simultaneous substitution of and oxidative addition to dinuclear rhodium(I) complexes (equation 224). The anions give resonances at very low fields in the H NMR spectra of the complexes.1050 The physical properties of the monohydrido complexes are listed in Table 77. 

The tren-based heteroditopic receptor 22, featuring a tripodal tetrahedral amide hydrogen-bond anion-recognition site in combination with benzo-15-crown-5 ether cation-binding moieties, has been found to cooperatively bind chloride, iodide, and perrhenate anions via co-bound crown ether-complexed sodium cations. It also can efficiently extract the radioactive sodium pertechnetate from simulated aqueous nuclear waste streams. The anion-binding affinity of 22 is considerably reduced in the absence of a co-bound cation <1999CC1253>... 

The formation of the stable hydrogen-bonded anions accounts in part for the extreme acidity. In the liquid add the fluoride ion is the conjugate base, and ionic fluorides behave as bases. Fluorides of M+ and M2+ are often appreciably soluble in HF, and some such as T1F are very soluble. 

The possible types of hydrogen-bonded anion complex are set out in Table 8.5, arranged in order of increasing H XO ratio. 

Hydrogen-bonded anion complexes in acid salts and crystalline oxy-acids... 

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