Platinum amine derivatives

The first structurally characterized example of a platinum(II) derivative containing a saturated tetraamine macrocycle, 6,13-dimethyl-l,4,8,ll-tetraazacyclotetradecane-6,13-diamine has been reported (80).251 The species crystallizes as the colorless tetra-cationic complex from dilute HC104 solution by slow evaporation, where the two pendant primary amines are protonated. Other macrocyclic tetraamine complexes including [Pt([14]aneN4)]Cl2 have also been described.252... 

Platinum (IV) Structures. The oxidation state of the platinum atom in platinum coordination compounds determines the steric configuration of the molecule platinum(II) structures are planar molecules, while platinum(IV) derivatives assume an octahedral shape. Though it was hoped that these differences could be used to circumvent platinum resistance, the two compounds developed in the clinic, iproplatin and ormaplatin, have not proven useful. In the case of the former, testing in Phase-II trials failed to reveal activity. In the case of ormaplatin, the platinum(IV) configuration is not maintained under biological conditions conversion to a platinum(II) metabolite occurs within minutes [14], A series of novel platinum(IV) and mixed ammine/amine derivatives being developed at the Institute for Cancer Research are described in this volume by Kelland. 

The influence of cobalt(III)—amine cations on native and denatured calf thymus DNA was first reported in 1972—3 [87, 88]. Subsequent studies on tRNA [89] and DNA [90] confirmed that such complex cations are very effective in stabilizing secondary and tertiary structures of nucleic acids. Karpel et al have extended the studies on cobalt to a series of platinum metal derivatives and the results are summarized in Table l.III 91]. 

E. Balint, E. Fazekas, G. Pinter, A. Szollosy, T. Holczbauer, M. Czugler, L. Drahos, T. Kortvelyesi, G. Keglevich, Synthesis and utilization of the bis(>P(0)CH2)amine derivatives obtained by the double Kabachnik-Fields reaction with cyclohexylamine quantum chemical and X-ray study of the related bidentate chelate platinum complexes, Curr. Org. Chem. 16 (2012) 547-554. 

Secondary amines synthesized by catalytic reductive alkylation of primary amines are used in a variety of fine and specialty chemical indnstries. For example, derivatives of cyclohexylamine are used as corrosion inhibitors, N-(l,3-dimethylbntyl)-N -phenyl-p-phenylenediamine (6-PPD) is nsed as an anti-oxidant in rabber indnstiy, several dialkylated diamines are used in the coatings indnstiy, while they are nsed in the pharmacentical industry as pharmacophores (1-7). Harold Greenfield and co-workers have examined the ability of platinum group metals (PGM), base metals, and their snlfides to catalyze rednctive alkylation of primary and secotrdary amines (8-11). They found that different catalysts are optimal for the... 

Chelate complexes of the type [PdX2(diene)] (X = Cl, Br) are readily formed by the dienes hexa-1,5-diene (124), bicyclo 2,2,lJhepta-2,5-diene (1, 7) tricyclo[4,2,2,0]-deca-triene and -diene derivatives (10), cyclo-octa-1,5-diene and dicyclopentadiene, but not dipentene (43). These may be converted to complexes of the types [Pd2X2(dieneOR)2] and [PdCl(dieneOR)-(amine)] (R = alkyl) (43), and their properties indicate that they have similar structures to the platinum complexes (XXXI) and (XXXIII). 

According to reaction (559) these reactions can occur by an oxidation reaction of platinum(II). With one-electron oxidants, the intermediate formation of platinum(III) complexes occurs. The best early example of this type of reaction is in the oxidation of PtCi - and Pt(en)2+ by IrIVCl - in the presence of free chloride ion. The presence of platinum(III) intermediates has been inferred from the rate law.2036 For the oxidation of platinum(II) by gold(III) the kinetic data are consistent with a mechanism requiring a complementary two-electron transfer,2037 with a rate independent of chloride ion. For the substituted pyridine derivatives PtCkLj (L = substituted pyridine) however, the third-order rate law is found with first-order dependencies on PtCl I, Aum and Cl-.2038 Comparisons have been made with the amine complexes PtC L (L = NH2R).2039... 

---