Thermolabile Noble Metal Precursors: (NO)[Au(NO₃)₄], (NO)₂[Pd(NO₃)₄], and (NO)₂[Pt(NO₃)₆]

Abstract

Oxidizing noble metals: Pure N2O5 can oxidize elemental gold and palladium. The complex nitrates obtained by these reactions, (NO)[Au(NO3)4], (NO)2[Pd(NO3)4], and also the first nitrate of tetravalent platinum, (NO)2[Pt(NO3)6] (see picture for the anion: Pt gray, N green, O blue), have the potential to act as precursors owing to their high thermolability. The thermal decomposition of (NO)[Au(NO3)4] was elucidated in detail by several methods.

Homoleptic Poly(nitrato) Complexes of Group 14 Stable at Ambient Conditions

“…The covalent character of E-ONO 2 bonds causes a significant lowering of the activation barrier for the elimination of NO 2 in comparison to the NO 3 − ion in salts. Intriguingly, polynitrato complexes occupy a place between these extremes.…”

“…Attempts to synthesise Pb(NO 3 ) 6 2− , Ge(NO 3 ) 6 2− or Ge(NO 3 ) 4 (2b) using this method, however, failed and afforded GeO 2 and Pb(NO 3 ) 2 , respectively, instead. 25 An alternative preparative method for polynitrates involving silver nitrate as a NO 3 In the exploration of potential routes for the synthesis of the hexanitrato complexes of silicon, germanium and tin, two approaches were taken. In a direct approach (i), a suitable halide is allowed to react with a large excess of nitrate salt of a non-coordinating cation avoiding the intermediate formation of the highly reactive charge-neutral tetranitrates.…”

“…A comparison of the structural parameters derived from the X-ray diffraction studies reveals a number of interesting trends (Table 1). Even though all hexa(nitrato)complexes E(NO 3 Table 1. Characteristic bond length ranges [Å] and angles [°] in the E(NO 3 ) n ] (4 − n)2− complexes of 1c-3c (n = 6) and 1b (n = 4) The available data can be interpreted tentatively in terms of NO 2 With the exception of the D 3d symmetry, for which one imaginary frequency was found, all conformer models lead also to stable minima upon taking account of solvent (MeCN) within the polarisable continuum model (PCM).…”

Cerium(III) Nitrate Derived CeO2 Support Stabilising PtOx Active Species for Room Temperature CO Oxidation

“…In contrast to the platinum(IV) nitrate solution, the [Pt 2 *Pt 4 ] salt has exact composition and does not contain an excess of nitric acid, it is stable at normal conditions and can be dissolved in various organic solvents . Thermal decomposition of platinum(IV) nitrato complexes proceeds at relatively low temperatures and in an oxidative atmosphere results in the formation of Pt oxides …”

“…From a certain point of view, the use of platinum precursors with an oxygen coordination environment, provides a more explicit way for the preparation of (PtO x )/CeO 2 catalysts. Recently, the series of individual platinum(IV) nitrato complexes were isolated . Such compounds have a precise composition, with a purely oxygen environment around platinum atoms, and are reasonably stable in organic solvents.…”