Synthesis and Characterization of Platinum(II) Complexes ofl-Ascorbic Acid. Crystal Structure of Ascorbato-C²,O⁵-ethylenediamineplatinum(II) Dihydrate

Abstract

Reactions between diaminediaquaplatinum complexes [Pt(N∩N)(H2O)2]2+ and sodium ascorbate (NaHAsc) have been studied using 1H and 195Pt NMR spectroscopy. Mixtures of platinum ascorbate species were formed involving different binding modes of the ascorbate ligand, namely, [Pt(HAsc-O 3)(H2O)(N∩N)]+, in which a single ascorbate acts as a monodentate ligand, the bis(ascorbate)platinum complexes [Pt(HAsc-O 3)2(N∩N)] and [Pt(HAsc-O 3)(HAsc-C 2)(N∩N)], and [Pt(Asc-O 2,O 3)(N∩N)] and [Pt(Asc-C 2,O 5)(N∩N)], in which the ascorbate acts as a chelating ligand (N∩N = en, N,N-dmen, N,N‘-dmen, N,N,N‘,N‘-tmen; HAsc- = C6H7O6 -, Asc2- = C6H6O6 2-). The crystal structure of ascorbato-C 2,O 5-ethylenediamineplatinum(II) dihydrate, [Pt(Asc-C 2,O 5)(en)]·2H2O, was established by X-ray crystallography. A series of diphosphineplatinum complexes of the type [Pt(Asc-O 2,O 3)(P∩P)] (P∩P = dppm, dppe, dppp) was prepared from the corresponding [Pt(NO3)2(P∩P)] species. These have been characterized by elemental analysis and infrared and 1H and 31P{1H} NMR spectroscopies.

Synthesis of Oxalato‐Bridged (Oxo)vanadium(IV) Dimers Using L‐Ascorbic Acid as Oxalate Precursor: Structure and Magnetism of Two Systems

“…The present systems are somewhat stronger antiferromagnets than the two other structurally characterized compounds incorporating 1: [Ph 4 , but its structure has not been determined.…”

Structural and magnetic studies on mono- and polynuclear chromium ascorbate complexes

“…A group of complexes, prepared via reduction of several Cr VI species by ascorbate, has since been reported [7][8][9][10]. However, the structural information as yet available is still limited due to the problems commonly associated with the chemical instability of ascorbic acid, the low stability constants of the complexes [11] and their reluctance towards crystallization, excluding the few well characterized mixed ligand platinum ascorbate complexes [12][13][14][15][16].…”

Binary and ternary chromium(III) complexes with cellular reductants and DNA components isolated from redox type systems. Part 3. Chromium(VI) – L-ascorbic acid – adenine (adenosine, ATP)

“…The coordination of ascorbate anions in the solid state has been previously reported [21][22][23]31]. Ascorbic acid as a ligand ( Figure 1) has several oxygen atoms capable of coordination [21-23, 31, 33-35].…”

“…It is well known that the transition metal ascorbate complexes precipitate as amorphous solids [22]. The crystal structures that have been determined to date are those of platinium(II)-ascorbate complexes with amine ligands [22,23].…”