The First Example of acis-Platinum Analogue with Two Directly Bridged Imidazoles: [Pt(mimim)Cl₂].Et₄NCl

Abstract

The crystal structure of the title compound, tetraethy,1ammonium dichloro( 1 -methyl-2,2'-biimidazole-N 3, N 3 )platinum(H) chloride, (C8H20N)[PtClz(CTH8N4)]C1, has been determined from single-crystal X-ray diffraction data. The square-planar coordination sphere of the platinum consists of two N atoms of the biimidazole ligand and two C1 atoms in a cis arrangement. The average Pt--N and Pt---C1 distances are 2.017 and 2.309A, respectively. One Et4NC1 molecule co-crystallizes in the asymmetric unit.

Synthesis, characterization, structure, molecular modeling studies and biological activity of sterically crowded Pt(II) complexes containing bis(imidazole) ligands

“…This parallels the behavior of platinum complexes of 4,5-diazafluorenone in which the Pt-N distances are also rather short and the N-Pt-N angle is reduced [35]. Moreover, molecule 2b cocrystallized with tetraethylammonium chloride and the NH moiety of the unsubstituted imidazolyl ligand interacts with the neighbouring chloride [36]. When the chelating fragment is enlarged to a six-membered ring, the molecule adopts a less strained, shallow boat-like geometry such that the platinum and the hydroxylbearing carbon are folded away from the central C 2 N 2 plane by 21°a nd 26°, respectively.…”

Dinuclear nucleobase-anion-bridged complexes of Pd II and Pt II with 1-methylimidazol-2-yl pyridin-2-yl ketone: synthesis, crystal structure and solution behaviour

“…1.366 ( 15) 1.362( 14) 1.433 ( 15) 1 .5 1 3( 1 4) 1.394 (13) 1.341 ( 15) 1.376 ( 15) 1.385 ( 15) 107.0(9) 107. 6(9) 125.1(9) 127.0(9) 1 2 1.9( 1 0) 119.8 (10) 1 I7.8(8) 120.9 (9) 12 1.5 (8) 116.6(9) I18.5 (10) 1 2 1.2( 1 0) 1 18.6( 10) 1 20.4 ( 10) Table 5 Structural details of homonuclear mthy-and mura-bridged complexes of Pd" and Pt" dM . .…”

Novel Platinum(II) Complexes with Dipyridyl Containing Chelating Ligands and their Products with the Model Nucleobases 1-Methylthymine and 1-Methyluracil

“…6). The large peaks at d = ±1900 (6) and d = ±1901 (7) probably due to the dinuclear species [Pt 2 (dpk) 2 (1-MeT) 2 ] 2+ (6) and [Pt 2 (dpk) 2 (1-MeU) 2 ] 2+ (7) in a head-to-tail arrangement. Peak 1 belongs to species [Pt(dpk)(H 2 O) 2 ] 2+ whereas peak 2 is assigned to the species [Pt(dpk) 2 ] 2+ .…”

“…This spectrum shows only two peaks at d 1 = ±1607 and d 2 = ±2257. The peaks at d = ±1628 and d = ±2192 (6) and also those at d = ±1627 and d = ±2176 (7) are due to the species [Pt 2 (dpk)(dpk´H 2 O)(1-MeT) 2 ] 2+ (6) and [Pt 2 (dpk)(dpk´H 2 O)(1-MeU) 2 ] 2+ (7) in a head-tohead arrangement. Additionally, the 195 Pt NMR spectra of the reaction mixtures of 6 and 7 were measured.…”

“…The platinum complexes of several bis(imidazole) ligands [3±5] and the unsymmetric ligand (1-methylimidazole-2-yl)-(pyridine-2-yl)ketone [6] display significant cytostatic activity, even though the tertiary amines do not form hydrogen bonds to DNA constituents, which are considered to be necessary for antitumor activity [7]. The platinum complexes of several bis(imidazole) ligands [3±5] and the unsymmetric ligand (1-methylimidazole-2-yl)-(pyridine-2-yl)ketone [6] display significant cytostatic activity, even though the tertiary amines do not form hydrogen bonds to DNA constituents, which are considered to be necessary for antitumor activity [7].…”