121 research outputs found
Metalâorganic complexation in the marine environment
We discuss the voltammetric methods that are used to assess metalâorganic complexation in seawater. These consist of titration methods using anodic stripping voltammetry (ASV) and cathodic stripping voltammetry competitive ligand experiments (CSV-CLE). These approaches and a kinetic approach using CSV-CLE give similar information on the amount of excess ligand to metal in a sample and the conditional metal ligand stability constant for the excess ligand bound to the metal. CSV-CLE data using different ligands to measure Fe(III) organic complexes are similar. All these methods give conditional stability constants for which the side reaction coefficient for the metal can be corrected but not that for the ligand. Another approach, pseudovoltammetry, provides information on the actual metalâligand complex(es) in a sample by doing ASV experiments where the deposition potential is varied more negatively in order to destroy the metalâligand complex. This latter approach gives concentration information on each actual ligand bound to the metal as well as the thermodynamic stability constant of each complex in solution when compared to known metalâligand complexes. In this case the side reaction coefficients for the metal and ligand are corrected. Thus, this method may not give identical information to the titration methods because the excess ligand in the sample may not be identical to some of the actual ligands binding the metal in the sample
Determination of PtâDNA adducts and the sub-cellular distribution of Pt in human cancer cell lines and the leukocytes of cancer patients, following mono- or combination treatments, by inductively-coupled plasma mass spectrometry
This is the authorâs version of a work that was accepted for publication in the International Journal of Mass Spectrometry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published at: http://dx.doi.org/10.1016/j.ijms.2010.11.01
Ab initio calculations on cis-[ PtCl
The capacity of Hartree-Fock (HF), MĂžller-Plesset second order perturbation
(MP2), and density functional (DF) calculations to predict the experimental
dipole moment and the metal-ligand bond lengths of a planar platinum(II)
complex, cis-[ PtCl2(PMe3)2] , was investigated. Highly erroneous
results were obtained from uncorrelated HF calculations and from MP2 and
DF calculations which included the 5s and 5p electrons of platinum in
a frozen core or in an effective core potential. DF calculations including
these (n-1)s and (n-1)p electrons in the valence space are shown to have
the ability to correctly reproduce the platinum-ligand bond lengths and the
dipole moment, provided that sufficiently large basis sets including
polarization functions are used. MP2 calculations yielded dipole moments
comparable to those obtained from DF calculations with the same basis set
and reproduced better the difference between the Pt-Cl and Pt-P bond
lengths, but required 2-6 times more computer time. The best agreement
between calculated and experimental dipole moment and bond length values
was obtained with DF calculations using the program ADF, provided that the
scalar relativistic terms were included in the hamiltonian. Our results
indicate that the mutual influence of the platinum-ligand bonds in
trans-position (the so-called trans-influence) involves both electron
correlation and relativistic effects
cis-Dichloro(di-n-butyl sulfide)(tri-n-butylphosphine)platinum(II)
International audienc
Reaction between the diaqua form of cisplatin and 2-methylsulfanylphenylphosphonic acid yields a dinuclear phosphonato-bridged complex via NH3 elimination
Reaction between cis-[Pt(NH3)(2)(H2O)(2)](2+) and (2-methylsulfanyl)phenyl phosphonic acid (H(2)mspp) did not yield the expected cis-diammine [(2-methylsulfanylphenyl)phosphonato]platinum(II) but the dimeric compound [(Pt(mspp)(NH3)}(2)] . 6H(2)O in which the dianionic mspp(2-) ligand acts both as chelator and bridging ligand. Thus, the high trans-effect of the sulfanyl group apparently leads to elimination of one NH3 ligand. An X-ray crystal structure analysis of the dimeric complex is reported
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