PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Organometallic Compounds”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2003

Band composition analysis: a new procedure for deconvolution of the mass spectra of organometallic compounds.

A new chemometric procedure called band composition analysis (BCA) designed for the deconvolution of mass spectra of organometallics is proposed. BCA generates theoretical bands T(i), then combines them to obtain a model band M, which is finally compared with the experimental band E. All of these steps are realized with computer assistance. This modeling yields four parameters characterizing the experimental band: theoretical and model variances s(2) (theor) and s(2) (model), a fit factor alpha and a contribution x(i) from the theoretical band. If s(2) (theor) > 20 the band is deemed complex and needs modeling. The values alpha > 90 indicate that there is good agreement between the experimental and model bands. BCA is particularly effective for the modeling of complex isotopic bands often present in organometallics. Two illustrations of BCA for tetrabutyltin, C(16)H(36)Sn, and 1,1',2,2',3,3'-hexachloroferrocene, C(10)H(4)Cl(6)Fe, are shown.

Ferrous Compounds↗
PubMed2001

Development of novel water-soluble, organometallic compounds for potential use in nuclear medicine: synthesis, characterization, and (1)H and (31)P NMR investigations of the complexes fac-[ReBr(CO)3L] (L=bis(bis(hydroxymethyl)phosphino)ethane, bis(bis(hydroxymethyl)phosphino)benzene).

The bidentate, water-soluble phosphine ligands, bis(bis(hydroxymethyl)phosphino)benzene (HMPB, 1) and bis(bis(hydroxymethyl)phosphino)ethane (HMPE, 2) were reacted with the organometallic precursor fac-[ReBr(3)(CO)(3)](2-), 3, to produce the complexes fac-[Re(OH(2))(CO)(3)L](+) and fac-[ReBr(CO)(3)L] (L = HMPE, HMPB), respectively, in good yields. The rhenium complexes fac-[ReBr(CO)(3)HMPB], 5, and fac-[ ReBr(CO)(3)HMPE], 8, were characterized using (1)H and (31)P NMR spectroscopy. The structure of fac-[ReBr(CO)(3)HMPB] was confirmed by single-crystal X-ray spectroscopy. The substitution reactions of HMPE/HMPB with the rhenium precursor 3 in aqueous solution were monitored using time-dependent (31)P NMR techniques. A significant discrepancy in the reaction kinetics and the substitution mechanism between the two bidentate ligands could be observed presumably due to the different chemical backbones.

Crystallography, X-Ray↗
PubMed2001

Is water a friend or foe in organometallic chemistry? The case of group 13 organometallic compounds.

This Account summarizes the recent developments in the hydrolysis chemistry of Group 13 trialkyl and triaryl compounds. Emphasis has been placed on the results obtained by us on (a) 1H NMR investigations of controlled hydrolyses of AlMes3 and GaMes3, (b) low-temperature isolation of water adducts of triaryl compounds of aluminum and gallium, (c) synthesis and structural characterization of new polyhedral alumoxanes and galloxanes, and (d) the search for an easy way to synthesize well-defined crystalline methylalumoxanes by deprotonation of the hydroxides with alkyllithium reagents. The systematic studies on the hydrolysis of tBu3Al carried out by Barron et al. are also discussed in order to elucidate the roles of (i) reaction temperature, (ii) solvent medium, and (iii) source of water molecules, in building up hitherto unknown alumoxane clusters. The role of water impurity in organometallic reactions involving a Group 13 alkyl and other ligands (such as silanetriols and phosphorus acids) to build molecular clusters has also been discussed.

Hydrolysis↗
PubMedDate not supplied

Antitumor activity of new organometallic compounds in human ovarian cancer cell lines and comparison to platin derivatives.

Cisplatin, Carboplatin and new compounds such as Paclitaxel and Docetaxel are effective drugs in the treatment of ovarian cancer. Multidrug resistance however remains an issue in ovarian cancer. The search for new effective drugs will remain of the highest priority in the field of cancer research. The in vitro and in vivo growth inhibiting potencies of two new metallocene dichlorides, Titanocendichloride and Vanadocendichloride, were compared to Cisplatin and Carboplatin using 20 permanent human ovarian cancer cell lines. Under in vivo and in vitro conditions Cisplatin was more effective than Carboplatin. Under in vitro conditions a Vanadocendichloride concentration of as low as 1.5 x 10(-7) mol/l resulted in a 50% decrease in the cell proliferation. Titanocendichloride inhibited cellular growth only at concentrations of 10(-4) mol/l. In contrast, Titanocendichloride was more effective in inhibiting growth of xenotransplanted ovarian cancer cell lines in nude mice. The clinically supposed equipotentiality of Carboplatin should be handled cautiously. The new organometallic substances clearly exhibit antiproliferative properties in ovarian cancer cells and are considered for clinical phase I trials.

Animals↗
PubMed2005

Effect of the interface on separation in multicapillary gas chromatography-based hyphenated techniques for speciation analysis of organometallic compounds.

This paper reports the effect of transfer line (TL) internal diameter (i.d.) on gas chromatographic separation characteristics such as efficiency and speed, when a multicapillary (MC) column is used for speciation analysis of mercury. Five different TL consisting of fused-silica capillaries with 0.15, 0.20, 0.25, 0.32, and 0.53 mm i.d. are compared. The separation efficiency and total chromatographic run time are critically affected by the i.d. of the TL. Narrow capillaries (i.d.< or =0.20 mm) produce minimum peak dispersion whereas wide capillaries result in narrow peaks and shorter chromatographic analysis times. A thermodynamic approach is proposed to describe the motion of the analytes through the separation column and TL. The model provides good agreement with the experimental data for high pressures (> or =35 psig) and wide TL (> or =0.25 mm i.d.).

Chromatography, Gas↗
PubMed2002

Biophysical analysis of natural, double-helical DNA modified by a dinuclear platinum(II) organometallic compound in a cell-free medium.

Modifications of natural DNA by the dinuclear platinum(II) organometallic complex [[Pt(Me)Cl(Me(2)SO)](2)(mu-N-N)] [where N-N=H(2)N(CH(2))(6)NH(2)] (ORGANObisPt) were studied by methods of molecular biophysics. These methods include DNA binding studies using atomic absorption spectrophotometry, HPLC analysis of enzymatically digested DNA, interstrand cross-linking employing gel electrophoresis under denaturing conditions, DNA unwinding studied by gel electrophoresis, mapping of DNA adducts by transcription assay, DNA melting curves measured by absorption spectrophotometry and conformational analysis of platinated DNA by differential pulse polarography. The results indicate that the complex ORGANObisPt binds irreversibly to DNA. Its DNA binding mode is, however, different from that of the formally equivalent [[cis-PtCl(NH(3))(2)](2)(mu-N-N)] (1,1/c,c), which exhibits antitumor activity including that in the tumor cells resistant to cisplatin. Interestingly, ORGANObisPt binds to DNA considerably faster than 1,1/c,c and cisplatin. In addition, when ORGANObisPt binds to DNA it exhibits a strong base sequence specificity to guanine residues. ORGANObisPt forms mainly monofunctional adducts on double-helical DNA. It forms also a small amount of DNA interstrand cross-links (approximately 2%), i.e. a radically smaller amount in comparison with the complex 1,1/c,c. Importantly, these interstrand cross-links of ORGANObisPt are capable of terminating RNA synthesis in vitro, while its major monofunctional adducts are not. In addition, the adducts of ORGANObisPt affect the conformation of DNA, but in a different way than its dinuclear analogue 1,1/c,c or cisplatin. Some structural features of ORGANObisPt, such as the charge or nature of the trans and cis activating groups relative to the labile chloride, might be responsible for the altered DNA binding mode and biological activity in comparison with the 1,1/c,c compound.

Biophysical Phenomena↗