Edward A. Heintz

Bio: Edward A. Heintz is an academic researcher from Union Carbide. The author has contributed to research in topics: Potassium & Thermal decomposition. The author has an hindex of 4, co-authored 7 publications receiving 42 citations.

Observations on Potassium Hexacyanotitanate (III)

Abstract: Schlaffer and Gotz1 have recently prepared a complex cyanide of titanium by reacting a liquid ammonia solution of titanium (III) bromide with excess potassium cyanide. Chemical analysis of the dark green precipitate leads to the empirical formula K5Ti(CN)8. However, comparison of the absorption spectra with those of known trivalent titanium complexes2,3 showed that the compound contained hexaco-ordinate titanium and should be assigned the formula K3Ti(CN)6·2KCN. Although eight co-ordinate titanium (III) has been reported4, and cyanide usually results in the highest co-ordination number of the central metal ion, the agreement of the absorption spectra with hexaco-ordinate complexes makes the higher co-ordination doubtful3. Carduck5 has also reported the existence of a dark green complex cyanide of titanium having the formula K3Ti(CN)6·3KCl prepared by mixing stoichio-metric solutions of titanium (III) chloride and potassium cyanide in liquid ammonia. The excess potassium chloride could not be removed from the precipitate by repeated washings with liquid ammonia. It is not clear how the excess potassium cyanide or potassium chloride is bound to the parent complex3, but the bond is apparently strong enough to resist removal when washed with excess liquid ammonia1,5.

Transition Metal Cyanides and Their Complexes

Abstract: Publisher Summary This chapter provides a critical review of the preparation, characterization (which is often incomplete), and properties of cyanide complexes of the transition metals. It focuses on structural, thermodynamic, and kinetic data. Two prominent features of transition metal cyanide chemistry are the wide range of metal:ligand ratios in complexes and the existence of many metals in low oxidation states. The chapter discusses the bearing of the physical state of metal cyanides on structural investigations. There are two important consequences of the fact that cyanide is an ion and not a neutral molecule: metal cyanides and their complexes are nonvolatile salts rather than volatile molecular entities and much of their chemistry is concerned with processes and measurements in solution in solvents of high complexing power, so that differences in complexing by solvent and ligand are involved. The chapter considers the effect of cyanide on the stabilities with respect to oxidation and reduction of metal ions in aqueous media, taking Fe(II) and Fe(III) as an example.

Palladium-Catalyzed Hydrohalogenation of 1,6-Enynes: Hydrogen Halide Salts and Alkyl Halides as Convenient HX Surrogates

Abstract: Difficulties associated with handling H2 and CO in metal-catalyzed processes have led to the development of chemical surrogates to these species. Despite many successful examples using this strategy, the application of convenient hydrogen halide (HX) surrogates in catalysis has lagged behind considerably. We now report the use of ammonium halides as HX surrogates to accomplish a Pd-catalyzed hydrohalogenation of enynes. These safe and practical salts avoid many drawbacks associated with traditional HX sources including toxicity and corrosiveness. Experimental and computational studies support a reaction mechanism involving a crucial E-to-Z vinyl–Pd isomerization and a carbon–halogen bond-forming reductive elimination. Furthermore, rare examples of C(sp3)–Br and −Cl reductive elimination from Pd(II) as well as transfer hydroiodination using 1-iodobutane as an alternate HI surrogate are also presented.

Anhydrous Metal Nitrates

Abstract: Publisher Summary Nitrates of many metals are known in hydrated form, but very few anhydrous nitrates had been prepared until recently. This applies particularly to the transition metals, where attempts to remove the molecules of water from the hydrate usually lead to hydrolytic decomposition through hydroxide nitrates to the hydroxide or the oxide, with evolution of nitric acid. This chapter discusses the versatility in nitrate chemistry. It is not yet possible to present a completely systematic picture, because the anhydrous nitrates of some metals have still to be prepared and many aspects of the bonding and reactivity of metal nitrates have not yet been explored. The chapter focuses on individual compounds that are representative of particular structures or properties. It provides a summary of properties characteristic of free nitrate ions and ionic nitrates, so that comparison can be made with the covalent nitrates and their derivatives. The chapter also gives a systematic review of the metal nitrates now known, surveyed on the basis of the Periodic Table.

The Hexacyanotitanate Ion: Synthesis and Crystal Structure of [NEt4]3[TiIII(CN)6]·4MeCN

Abstract: The hexacyanotitanate salt, [Et4N]3[Ti(CN)6]·4MeCN, has been prepared by addition of tetraethylammonium cyanide to the titanium(III) triflate salt Ti(O3SCF3)3(MeCN)3. The orange crystalline product has been characterized by X-ray diffraction, and the d1 anion is only slightly distorted from ideal Oh symmetry. The anion resides on a center of symmetry and is characterized by the following parameters: Ti−C = 2.195(2), 2.197(3), and 2.213(3) A; C−N (av) = 1.141(4) A; C−Ti−C (cis) = 88.01(9), 88.02(9), 89.02(9), and 89.78(9)°; C−Ti−C (trans) = 180°. In addition to the crystallographic study, details of the IR (νCN = 2071 cm-1), EPR, and UV−vis spectra (Δo = 22800 cm-1) are given. Crystal data for [Et4N]3[Ti(CN)6]·4MeCN are as follows: monoclinic, space group I2/a, a = 18.171(6) A, b = 12.200(4) A, c = 20.989(5) A, β = 91.17(2)°, V = 4652(2) A3, Z = 4, wR2 = 0.2054 for 3831 data, 27 restraints, and 318 parameters.