Trinegative ions

Triclinic crystal system, 75, 78 Trigonal bipyramidal (TBP) structure, 480-483 Trigonal crystal system, 75, 78 Trigonal hybrid, 150-153 Trigonal prism, 489-491 Trimethylborane, 205 Trinegative ions, 332-333 Trinuclear clusters, 813-815 Tropylium complexes, 683-684 Tutankhamen, 458 Twist angles, 490... 

Trinegative ions Dinegative ions Uninegative ions Neutral molecules ... 

Dinegative and trinegative ions have no existence outside of a system, such as a lattice, that stabilizes them. These values are rather crude estimates from Bom-Haber cydes and indicate the relative difficulty or pulling a proton away from their conjugate acids. 

Correlation of the observed rates with the concentrations of the substrate species (10) indicates that the metal ion does not catalyze the hydrolysis of the monoanionic form of salicyl phosphate. Combination of the monoanionic form of the substrate with the vanadyl ion would result in an unreactive complex having a neutral carboxyl group. Shift of the proton to the phosphate group could not take place in accordance with the requirements of the general reaction mechanism illustrated in Figure 3. Thus the vanadyl ion would be expected to catalyze the hydrolysis of only the di- and trinegative forms of the substrate. 

It should be noted that the proton affinities of all of the trinegative and dincgative anions are calculated by means of a Bom-Haber cycle. They are not experimentally accessible since these ions have no existence outside of a stabilizing crystal environment—they would exothermically expel an electron (sec Chapter 2). 

Gas-phase proton affinities (Id mol-1)4 Trinegative eons Dmegafive ions ... 

Haines et al. investigated the stereoselective formation of bisfethyienediamine)-cobaltflll) complexes containing optically active tartaric acid from a reaction of [Co(C03)(en)2]Cl and S(—)-tartaric acid in water at steam-bath temperature, two optically active complexes, A-[Co(S-C4H40g)(en)2] Cl and A-[Co(S-C4H306)(en ], were isolated by TLC with silica gel. In the former complex, the tartrate ion acts as a bidentate chelate agent with one free carboxylic acid (IV), and in the latter the tartrate is trinegative. 

A more detailed study has been made (for Co +) where is iminodiacetate (ida ), nitrilotriacetate (nta ), and polytriphosphate (tp ). It was found (Table 3) that the rate constants and activation parameters for the trinegative anion [Co(tp)] were almost identical with those for the aquocation Co +, and the authors conclude that, as with nickel(n), char as such on the bound ligand has little effect on the reactivity of the metal ion with a neutral ligand. Nonetheless, there is a significant variation in formation rate constant on passing from Co + and [Co(tp)] to [Co(jda)] and [Co(nta)], and this is lar ly reflected in a variation in activation enthalpy, the... 

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