Triphenylmethylphosphonium trichloro(caffeine)platinum(II) [P(C6H5)3(CH3)][PtCl3(caffeine)], structure and anticancer activity

Abstract

The salt [PPh3Me] [PtCl3(caffeine)] has been synthesized and its structure determined. It crystallizes in the triclinic space group C)-P\ with cell dimensions at -162 °C of a = 12.332 (5) Á, b = 13.230 (6) Á, c = 8.712 (4) Á, a = 97.07 (2)°, ß = 99.78 (4)°, y = 93.63 (1)°, V = 1385 Á3, and Z = 2. The structure was solved by heavy-atom methods, and the 217 variables were refined by least-squares techniques to a final R index on F of 0.038 for the 5670 data. The structure consists of discrete [PPh3Me]+ cations and [PtCl3(caffeine)]" anions. The square-planar Pt(II) ion is bound to atom N(9) of the caffeine ligand at a distance of 2.021 (5) Á. The related salt K[PtCl3(caffeine)] has significant anticancer activity.a The low-temperature system is based on a design by: Huffman, J. C. Ph.D. Thesis, Indiana University, 1974. 6 The diffractometer was run under the Vanderbilt disk-oriented system (Lenhert,

Purine complexes of platinum: synthesis, nmr, and crystal and molecular structures of cis-chloro(caffeine)bis(triethylphosphine)platinum(II) fluoroborate and cis-bis(isocaffeine)bis(triethylphosphine)platinum (II) fluoroborate

“…The bond lengths and bond angles within the caffeine ligand are essentially identical within experimental error with those reported previously in the complexes, [CuCI,(H20)(caff)l ( 17) and [PtCl,(caff)l- (18), the conlparison with the latter being especially exact. The only slight discrepancy concerns the N7-C8-N,, angle in the imidazole ring, where the present value of 109" is close to that found in [H(caff)] ' (109.6") rather than to the more usual value of 112-113" found in caffeine itself and in other N-bonded caffeine complexes (18).…”

“…The only slight discrepancy concerns the N7-C8-N,, angle in the imidazole ring, where the present value of 109" is close to that found in [H(caff)] ' (109.6") rather than to the more usual value of 112-113" found in caffeine itself and in other N-bonded caffeine complexes (18). As in previous examples the caffeine shows significant departures from planarity, notably a slight dihedral angle (2.3") between the 5-and 6-membered rings.…”

“…As in previous examples the caffeine shows significant departures from planarity, notably a slight dihedral angle (2.3") between the 5-and 6-membered rings. Within the platinum coordination sphere, the Pt-N distance is longer, 215 pnl, in the present complex than in [PtC17(caftjl-, 202 pm (18), reflecting the greater tr-arzs influence of phosphorus relative to chlorine. On the basis of tr-at1.s-Pt-CI bond lengths, the tr-mls intluence of caffeine itself has been suggested to be similar to that of simple nitrogen donors (18) and this view is confirmed by the Pt-P bond length trurls to caffeine in the present complex.…”

“…Several crystallographic studies of transition metal caffeine complexes have been reported previously ( 17,18). Structures of isocaffeine complexes are very few, but a recent paper ( 19) gives two crystal structures containing the ion [Pt(en)(isocaff),]" .…”

Modern Applied Science, Vol. 3, No. 12, December, 2009

“…Moreover, the spectra of the complexes exhibited weak bands between 460-490 cm -1 due to (M-N). This indicates the coordination of Tp with the metal ions through the nitrogen atom N9 in their structures (Elizabeth, & Elmer, 1979;Katsuyuki, & Hiroshi, 1980;Milan, 1981;Roger, et al, 1981).…”