Reaction of a series of nitrogen donor ligands (1-phenylpyrazoles, 2-phenylpyridine, benzohquinoline, 1-(2′-pyridyl)indole, 1-phenylindazole, and 2-phenylindazole) with palladium(II) and platinum(II) ...salts gave complexes where ortho-metallation had occurred resulting in bidentate binding to the metal centres through N and C atoms. These cyclometallated products were isolated as µ-chloro dimers. Subsequent treatment of these µ-chloro dimers with chelating diamines such as 1,2-ethanediamine converted them into 14 cationic (1+) complexes. Analogous coordination mixed ligand complexes (charge 2+) were prepared by reaction of dichloro(1,2-ethanediamine-N,N′)palladium(II) with aromatic diamines such as 2-(1′-pyrazolyl)pyridine, 2,2′-bipyridine, and 1,10-phenanthroline. The complexes exhibited growth inhibitory activity against L1210 mouse leukæmia cells in vitro over a wide concentration range; in general, the cyclometallated complexes were more active than the mixed ligand complexes, although one cyclometallated organoplatinum complex was less active than the mixed ligand analogue. Substitution around the periphery of the aromatic ligands also resulted in increased activity. One complex, derived from 1-(2'-pyridyl)indole, was tested in vivo and showed no significant antitumour inhibition against P388 leukæmia at doses below toxic levels.
Key words: anticancer, metallointercalator, cyclometallation, palladium, platinum, cytotoxicity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The platinum(IV) complexes: PtCl
4(en),
cis,trans-PtCl
2(OAc)
2(en),
cis,trans-PtCl
2(OH)
2(en) and
trans-Pt(OH)
2(ethmal)(en), encompassing a range of reduction potentials and their platinum(II) ...analogue PtCl
2(en), have been assayed for their protein binding ability in the presence of albumin, albumin and
l-cysteine and RPMI 1640 tissue culture medium supplemented with foetal calf serum (RPMI/FCS).
cis,trans-PtCl
4(en) exhibited significant protein binding in all three experiments, in a similar fashion to the platinum(II) complex, presumably as a consequence of its rapid reduction. The remaining three platinum(IV) complexes displayed little if any protein binding, with the greatest amount of binding observed in the RPMI/FCS experiment. The extent of binding in the RPMI/FCS correlated with the reduction potentials of the complexes, with the most readily reduced species binding to the greatest extent.
Four structural classes have been established for rare earth anthranilates, which have been prepared from the lanthanoid chloride or triflate and anthranilic acid followed by pH adjustment to 4. ...Polymeric structures are observed for lanthanum and ytterbium, a dimeric complex for erbium, and a monomer for neodymium (pictured). The anthranilate ligands exhibit a diverse range of binding modes within the four structural classes.
Four structural classes have been established for rare earth anthranilates, which have been prepared from the lanthanoid chloride or triflate and anthranilic acid (anthH) followed by pH adjustment to 4. La(anth)
3
n
is a polymeric complex with nine coordinate lanthanum and bridging tridentate (O,O,O′) anthranilate ligands, whereas Nd(anth)
3(H
2O)
3
·
3H
2O is monomeric with nine coordinate neodymium and solely chelating (O,O) anthranilate groups. Both chelating (O,O) and bridging bidentate (O,O′) ligands are observed in dimeric Er
2(anth)
6(H
2O)
4
·
2H
2O, in which erbium is eight coordinate and the water ligands are in a
trans arrangement. A polymer is observed for Yb(anth)
3(H
2O)
n
with solely bridging bidentate (O,O′) ligands and seven coordination for ytterbium. The NH
2 groups of the anthranilate ligands are not coordinated to the metal but is unusually involved in hydrogen-bond networks with water molecules for Ln
=
Er, Yb.
Uptake of platinum-based anticancer compounds into individual human ovarian andenocarcinoma cells was measured using an X-ray microprobe. The uptake of cisplatin, a platinum-based compound, in ...drug-resistant cells is decreased by approximately 50% after 24 h, compared with the uptake of the drug in nonresistant cells over the same time period. The Pt103 derivative of the drug, in contrast, showed an increased uptake by an order of magnitude in resistant cells over the same time period. Increased uptake appears to allow Pt103 to overcome the resistance mechanism developed by the cell. This work additionally shows that the X-ray microprobe is able to directly quantify Pt drug uptake on a subcellular level and can measure the mass of Pt down to a detectable limit of 20 attograms of Pt (2 x 10(-17) grams or 6 x 10(4) Pt atoms) in 1 s. Such exquisite elemental sensitivity combined with high spatial resolution paves the way for quantitative submicron three-dimensional mapping of elemental distributions within individual cells.
Reaction of 8‐hydroxyquinoline (HOQ) with holmium metal in the presence strontium metal and metallic mercury at 190 °C under vacuum in a 1,3,5‐tri‐tert‐butylbenzene flux yielded ...(η2‐8‐quinolinolato‐κ:N,O(Ho(2))bis(η2‐8‐quinolinolato‐κ:N,O(Ho(1)))hexakis(μ‐(O)‐8‐quinolinolato‐κ:N,O(Ho(1))trisholmium(III) as an 8‐hydroxyquinoline solvate (1) (C2/c, a = 17.336(4) Å, b = 23.464(5), c = 18.038(4) Å, β = 92.92(3)°, V = 7328(3) Å3, R1 = 0.0622). The complex was resynthesised after preactivation of the metals by mercury and then heating them with HOQ at 190 °C.
The syntheses and crystal structure determinations of a pair of 'sawhorse' dimers are reported, viz. Ru2(C6H5CO2)2-(C5H5N)2(CO)4 a new polymorph, cf. Kepert, Deacon. Spiccia, Fallon, Skelton and ...White (2000). J. Chem. Soc. Dalton Trans, pp. 2867-2874 and Ru2(CF3CO2)2(C5H5N)2(CO)4. The Ru *** Ru distances are 2.6724 (2) and 2.7122 (5) A. respectively.
Oxidation of Yb(C5Me5)2 with Tl(Ph2pz) and Tl(azin) (Ph2pz = 3,5-diphenylpyrazolate, azin = 7-azaindolate) yields Yb(C5Me5)2(Ph2pz) (1) and Yb(C5Me5)2(azin) (2). X-ray crystal structures of 1 and 2 ...reveal monomeric eight-coordinate complexes with η2-Ph2pz or azin ligands. Treatment of neodymium metal with Tl(Ph2pz) yields Nd(Ph2pz)3(dme)2 (3), which is a nine-coordinate monomer with three η2-pyrazolate ligands and a chelating and a unidentate dme ligand. Oxidation of Sm(C5Me5)2 with Tl(1,4,2-P2SbC2But 2)/Tl(1,2,4-P3C2But 2) (approximately 4:1) gave a mixture of Sm(C5Me5)2(1,2,4-P3C2But 2) (4) and Sm(C5Me5)2(1,4,2-P2SbC2But 2). The former was shown to be a nine-coordinate monomer with novel pseudo-pyrazolate η2-(P2)-1,2,4-P3C2But 2 coordination of the triphosphacyclopentadienide ligand. After metathesis routes to Ln(1,4,2-P2SbC2But 2) n complexes failed, redox transmetalation between ytterbium metal and Tl(1,4,2-P2EC2But 2) (E = Sb, P) containing a substantial impurity of Li(tmeda)21,4,2-P2EC2But 2 yielded the first lanthanoid diphosphastibacyclopentadienide complex in a mixture with 1,2,4-P3C2But 2 species. An X-ray investigation of single crystals containing an isomerically diverse mixture enabled the structure of Li(thf)4Yb(1,4,2-P2SbC2But 2)3 (5) to be determined, and it was shown to contain a π-η2 and two η5-1,4,2-P2SbC2But 2 ligands. In the series 1, 4, and 5, the η2-ring varies from edge-on to side-on, reflecting a progression from σ to π coordination. Li(tmeda)21,4,2-P2SbC2But 2 (6) has been successfully crystallized from a Li(tmeda)2P2EC2But 2 mixture and structurally characterized.
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