ABSTRACT
A series of palladium(ii) radical carbene complexes, [PCË(sp2)P]PdI, [PCË(sp2)P]PdBr, and [PCË(sp2)P]PdCl (PC(sp3)H2P = bis[2-(di-iso-propylphosphino)-phenyl]methane), is described. Compound [PCË(sp2)P]PdI dimerizes to {[PC(sp2)P]PdI}2 in the solid state, akin to the formation of Gomberg's dimer. While the bromo and the iodo derivatives could be obtained from the oxidation of [PC(sp2)P]Pd(PMe3) by the respective dihalogens, a halogen transfer reaction from CH2Cl2 was used for the formation of [PCË(sp2)P]PdCl. The halogen transfer from CH2X2 (X = Cl, Br, I) could be used to obtain all three radical carbene palladium complexes and also allowed the isolation of [PC(CH2)P]Pd(PMe3), which is the result of methylene group transfer from CH2X2. Compound [PC(CH2)P]Pd(PMe3) was independently synthesized from [PC(CH3)HP]PdCl2, which contains a supporting ligand analogous to that of the radical carbene complexes but has one of the hydrogen atoms replaced by a methyl group. All three carbene radical species abstract a hydrogen from 9,10-dihydroanthracene or n Bu3SnH.
ABSTRACT
Poly- and mononuclear metal complexes of 2,3,11,12-bis[4-(10-aminodecylcarbonyl)]benzo-18- crown-6 (L) and Cu(II); Ni(II); Co(II) and Cr(III) have been synthesized and characterized by standard physico-chemical procedures. In the newly prepared complexes the crown moiety oxygen atoms of the macrocyclic host did not generally interact with metal ions, whereas the two amino groups of the ligand always did. Several of the newly synthesized compounds act as effective antifungal agents against Aspergillus and Candida spp., some of them showing activities comparable to ketoconazole, with minimum inhibitory concentrations in the range of 0.3-0.5 mug/mL. The mechanism of antifungal action of these coordination compounds is probably connected to an inhibition of lanosterol-14-alpha-demethylase, a metallo-enzyme playing a key role in sterol biosynthesis in fungi, bacteria and eukariotes.
ABSTRACT
Metal complexes of dichloro-tetramorpholino-cyclophosphazatriene containing divalent cations such as Ni(II), Co(II), and Mn(II) have been prepared and characterised by standard physico-chemical procedures (elemental chemical analysis, IR and UV-VIS spectra, conductimetric measurement). The newly synthesised compounds possessed antifungal activity against Aspergillus and Candida spp., some of them showing effects comparable to ketoconazole (with minimum inhibitory concentrations in the range of 2- 30 mug/mL) but being generally less active as compared to the azole. Best activity was detected against C. albicans, and worst activity against A. niger. The mechanism of action of these compounds probably involves inhibition of ergosterol biosynthesis, and interaction with lanosterol-14-alpha-demethylase (CYP51A1), since reduced amounts of ergosterol were evidenced by means of HPLC in cultures of the sensitive strain A. niger treated with some of these inhibitors.
