Synthesis of aminoalcohol compounds of platinum and crystal structure of trans-[Pt(2-amino-2-methyl-1-propanol)₂Cl₂]

Abstract

Can. J. Chem. 62, 2657 (1984. Three types of complexes, trans-[Pt(LH),Cl,], [Pt(L),I, and [Pt(LH),(SR),I where LH = NH2-C(CH3)2(CH20H) and NH2--C(CH20H)3 and L are the deprotonated ligands, have been synthesized.The crystal structure of ~~~~S-[P~(NH,-C(CH~)~CH~OH)~C~~] has been determined by X-ray diffraction methods. The crystals are monoclinic, space group P2!/c, with a = 6,282(3), b = 20,901(13), c = 10,769(10) A, f3 = 92,64(6)", and Z = 4. The structure was refined by full-matrix least-squares analysis to a conventional R factor of 0.049 and R,, = 0.042. The coordination around the platinum atom is square planar. The Pt-C1 distances are 2.306(2) and 2.309(3) A and the Pt-N bonds are 2.060(8) and 2.07 l(7) A. The hydroxyl oxygen atoms are disordered; the disorder is different for each organic ligand.The structure is stabilized by an extensive hydrogen bonding system. We have modified these methods to prepare trans-[Pt(LH),- C12] add [Pt(L),] . Compounds of NH2-C(CH3),CH20H (identified below as L'H) were also synthesized. Organic sulphur compounds R-SH (thiophenol and thiouracil) can react with [Pt(L),] or [Pt(L1),] to form [Pt(LH),(SR),] (or L'H). The three types of complexes [Pt(LH),Cl,], [Pt(L),], and [Pt(LH),(SR),] (or L'H) are believed to be trans-isomers.In order to confirm these hypotheses, we wanted to determine the crystal structures of one compound of each type. Unfortunately, up to now, only [Pt(L1H),Cl2] gave suitable crystals for X-ray diffraction. Its crystal structure is reported below. Experimental[Pt(L2)l and lPt(L1),l K,PtC14 and LH or L'H were dissolved in water in a ratio of LH : Pt > 5. The mixture was heated to 50-70°C for about 1 h and then cooled to room temperature. The light yellow precipitate was filtered, washed with water, and dried with a vacuum pump overnight. The compounds crystallized with one (L) and two (L') molecules of water (Table 1). Yield: 80%.crystals slowly formed and they were washed with water and dried under vacuum overnight. Yield: 90%.[Pt(LH), ( A set of precession photographs showed that the crystals belong to the P 2 , l c space group. The cell parameters were calculated by least-squares refinement from the setting angles of 15 centered reflections on a Syntex P1 diffractometer using graphite-monochromatized MoKa radiation. A total of 4140 independent reflections were measured with 28 < 60" by the 8-28 scan technique using MoKa radiation. The scan rate was l o (28) min-' for most reflections, but rates as high as 24" min-I were selected for strong reflections by the autocollection program. A 28 scan range of lo below Ka, and lo above Ka, was chosen. The background time to scan time ratio was 0.50. Reflections with I,,, < Crystal data

trans-Bis(tert-butylamine)dichloroplatinum(II), C8H22Cl2N2Pt

“…The Pt-Cl bonds [2.299 (2) and 2.296 (2)A] and the Pt-N bonds [2.041 (6) and 2.053 (6)A] are normal and agree well with published values found in trans-aminochloroplatinum(II) compounds (Rochon, Kong & Melanson, 1984;Lock & Zvagulis, 1981). The two trans organic ligands are arranged so that one ligand is above the platinum plane, while the second is below the plane.…”

“…All the angles are close to the tetrahedral values (107-112°). The angles around the bonded N atoms [Pt-N-C = 122.9 (5) and 123.1 (5)°1 are quite far from the tetrahedral value, but similar values (113-122 °) have been observed for these types of compounds (Rochon, Kong & Melanson, 1984;Lock & Zvagulis, 1981;Rochon & Melanson, 1982).…”

Effects of Tris and Hepes buffers on the interaction of palladium–diaminopropane complexes with DNA

“…The first one relates to the idea of buffers as ligands. In fact, Tris and Hepes are both potential ligands for platinum [8] and it was assumed that Tris was more competitive than Hepes in competing with DNA for platinum, mainly due to steric factors [9,10]. This significantly affects the rate and efficiency of metal-complex binding to DNA.…”