Tris[cis-dichloro(1,2-diaminocyclohexane)-platinum(II)] hydrate and cis-dibromo(1,2-diaminocyclohexane)platinum(II)

Lock, C. J. L.; Pilon, Pierre

doi:10.1107/s0567740881002161

Cited by 32 publications

(6 citation statements)

References 11 publications

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“…For a variety of cis -PtCl 2 A 2 complexes, where A 2 represents two unidentate ligands or one didentate amine ligand, a bond length of 2.03 Å and a force constant of 366 kcal/(mol·Å 2 ) have been used for the Pt−N bond . Typical Pt−Cl bond lengths of cis -PtCl 2 A 2 compounds are ∼2.33 Å, − and on the basis of the IR spectra of Pt(NH 3 ) 4 2+ and PtCl 4 2- , the Pt−Cl bond is expected to be weaker than the Pt−N bond. , Therefore, a force constant of 240 kcal/(mol·Å 2 ) was selected. The right-angle parameters of the cis ligand bonds and the coaxial parameters of the trans bonds used previously for the modeling of platinum complexes of guanine derivatives 15,23 were adopted here.…”

Section: Methodsmentioning

confidence: 99%

“…Previous modeling studies have utilized the AMBER force field, which is commonly used for modeling of DNA and proteins, 14 with modifications to include parameters for platinum and the amine ligands. 15 [16][17][18][19][20] and on the basis of the IR spectra of Pt(NH3)4 2+ and PtCl 4 2-, the Pt-Cl bond is expected to be weaker than the Pt-N bond. 21,22 Therefore, a force constant of 240 kcal/(mol‚Å 2 ) was selected.…”

Section: Methodsmentioning

confidence: 99%

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Factors Influencing the Configuration and Conformation of Diamine Chelate Rings in Platinum(II) Compounds: 2,4-Bis(methylamino)pentane Complexes

et al. 1997

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Complexes of the type [PtX(2)(Me(2)DAP)] (Me(2)DAP = 2,4-bis(methylamino)pentane) have been prepared and studied by (1)H NMR spectroscopy, molecular mechanics/dynamics (MMD) calculations, and X-ray crystallography. The coordinated Me(2)DAP ligand has four asymmetric centers. Complexes with an enantiomeric form of the ligand (e.g., RR-Me(2)DAP, RR being the configurations of the two asymmetric carbons) have three possible configurations, namely, SRRR, RRRR, and SRRS at N, C, C, and N, respectively. Indeed these three isomers were obtained in respective ratios of 9:1: approximately 0 for X = I(-) and of 7:3:1 for X = Cl(-). Complexes with the meso ligand (RS-Me(2)DAP) have four possible configurations, i.e., SRSR, RRSS, RRSR, and SRSS at N, C, C, and N, respectively (the latter two constitute an enantiomeric pair). Only the two symmetrical isomers were obtained in the ratios of 9:1 for X = I(-) and 1:1 for X = Cl(-). In addition, the preferred chelate ring conformations in solution (CDCl(3)) were determined to be the following: delta-chair (SRRR), lambda-skew (RRRR), fluxional chair (SRRS), fluxional skew (SRSR), and lambda-chair (RRSS). This information was used to assess the contributions of intra- and interligand interactions to determine the conformational stability. MMD calculations employing the AMBER force field [as modified by Yao et al. (Yao, S.; Plastaras, J. P.; Marzilli, L. G. Inorg. Chem. 1994, 33, 6061) and extended to include parameters for the Cl(-) ligands] provided minimum-energy structures for all five X = Cl(-) complexes. These structures agreed well with the experimentally determined solution conformations except for SRSR, which had a lowest energy delta-chair instead of skew conformation. X-ray structural studies of the SRSR species (X = Cl(-) and X = I(-)) confirmed the delta-chair conformation. The results suggest that an equatorial N-methyl group has nonbonded clashes with the cis chloride ligand; therefore, axial N-methyl groups are favored. However, in solution, the solvent and entropy (connected with fluxionality of conformers) are factors which, to some degree, can overcome the interligand steric interaction.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Factors Influencing the Configuration and Conformation of Diamine Chelate Rings in Platinum(II) Compounds: 2,4-Bis(methylamino)pentane Complexes

et al. 1997

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“…Such hydrogenbonded molecular pairs, with a distance between the square planes of about 3.3 Å, correspond well to those for the cisdiaminodichloroplatinum() complexes. 21, 22 The short Pt ؒ ؒ ؒ Pt distance has also been found in the molecular structure of other diaminoligands 23 but until now it has not been established for the diaminosugar complex. 10, 11 The water molecules in the crystal lattice of complex 3 formed chain-type structures bridging the dimers (Fig.…”

Section: Solid State Structuresmentioning

confidence: 95%

Platinum(ii) and palladium(ii) complexes with methyl 3,4-diamino-2,3,4,6-tetradeoxy-α-l-lyxo-hexopyranoside

et al. 2003

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“…An interesting feature of this ligand is its ∼97°bite angle, 65 which is larger than that of cisplatin (∼90°; Chart 2) and of analogous compounds with ethylenediamine (en, 83°) 66 or 1,2-DACH (83.2°, average value of three Pt complexes). 67 The large bite angle of cis-1,4-DACH complexes could also reduce the (amine)NH 2 -Pt-N7(G) angles, thus possibly influencing the distribution of conformers and likely diminishing the ease of interconversion between possible conformers. Such an impeded interconversion was reported for the (cis-1,4-DACH)Pt-(5′-GMP) 2 adduct (having two untethered guanine derivatives), for which 1 H NMR evidence for all three possible conformers (HH, ΔHT, and ΛHT) was observed by lowering the temperature to −35 °C.…”

Section: Introductionmentioning

confidence: 99%

DNA fragment conformations in adducts with Kiteplatin

et al. 2015

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The anticancer activity of cisplatin is triggered by its formation of intrastrand adducts involving adjacent G residues of DNA. To obtain information on the different conformers that can be formed, carrier ligands such as 2,2'-bipiperidine, which provide large steric bulk near the platinum coordination plane and decrease the dynamic motion about the Pt-N7 bonds, were introduced ("retro-modelling" approach). In the present study we investigate the effect of cis-1,4-diaminocyclohexane (cis-1,4-DACH) on the formation, stability, and stereochemistry of (cis-1,4-DACH)Pt(ss-oligo) adducts (ss-oligo = d(GpG) with 3'-and/or 5'-substituents). Interesting features of this ligand, absent in previous retro-modelling studies, include the large bite angle (expected to impede the ease of interconversion between possible conformers), the presence of two protons on each nitrogen (a characteristic associated with antitumor activity), and the absence of chiral centres. The use of cis-1,4-DACH has made it possible to detect different conformers in a system containing a primary diamine carrier ligand associated with anticancer activity and to confirm the previous hypothesis that the coexistence of different conformers established in studies of retro models having relatively bulky ligands is not an artefact resulting from carrier-ligand bulk. Moreover, the data for the (cis-1,4-DACH)Pt(d(GpG)) and (cis-1,4-DACH)Pt(d(GGTTT)) adducts indicate that at a temperature close to the physiological one (40°C) HH1 and ΔHT1 conformers are present in comparable amounts. In contrast, at low temperature (close to 0°C) the equilibrium shifts dramatically toward the more stable HH1 conformer (for the (cis-1,4-DACH)Pt(d(TGGT)) adduct the HH1 conformer is always dominant, even at high temperature). Notably, (cis-1,4-DACH)PtCl 2 (Kiteplatin) has been recently reinvestigated and found to be particularly active against colorectal cancer (including oxaliplatin-resistant phenotypes).

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Tris[cis-dichloro(1,2-diaminocyclohexane)-platinum(II)] hydrate and cis-dibromo(1,2-diaminocyclohexane)platinum(II)

Cited by 32 publications

References 11 publications

Factors Influencing the Configuration and Conformation of Diamine Chelate Rings in Platinum(II) Compounds: 2,4-Bis(methylamino)pentane Complexes

Factors Influencing the Configuration and Conformation of Diamine Chelate Rings in Platinum(II) Compounds: 2,4-Bis(methylamino)pentane Complexes

Platinum(ii) and palladium(ii) complexes with methyl 3,4-diamino-2,3,4,6-tetradeoxy-α-l-lyxo-hexopyranoside

DNA fragment conformations in adducts with Kiteplatin

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