Cyanines during the 1990s: A Review

Anti-cancer drugs

On the medicinal chemistry of gold complexes as anticancer drugs

Flipping the light switch 'on'--the design of sensor molecules that show cation-induced fluorescence enhancement with heavy and transition metal ions.

The coordination chemistry of guanidines and guanidinates

A new dimeric paramagnetic Pt(II)-Pt(III) complex bridged by two o-phthalic monoanions was synthesized and its stncture studied using spectroscopic (EPR. IR, 13C and 195Pt NMR) and magnetochemical methods. The coordination mode of the ligand (coordination via the hydroxy groups) was proven by IR and 13C NMR data and the oxidation state of the platinum ion by EPR, 195Pt NMR and magnetochemical data.

Synthesis and Structure of a new Dimeric Pt(II)-Pt(III) Complex with o-Phthalic Acid

Vipoxin is a heterodimeric neurotoxin isolated from the venom of the Bulgarian long-nosed viper Vipera ammodytes meridionalis. Vipoxin represents a noncovalent association of two subunits – a basic and toxic phospholipase A2 enzyme, and an acidic non-enzymatic component (vipoxin's acidic component). It was postulated that the phospholipase A2 subunit was more toxic than the whole vipoxin complex and the function of the acidic component was to reduce the enzymatic and toxic activities of the basic phospholipase A2. In the present study, we report new data on the acute toxicity (LD50) of vipoxin and its individual separated components. Vipoxin LD50 (mice, i.p. and i.v.) values were found to be 0.7–1.2 mg/kg b.w. (i.p.) and 0.9–1.3 mg/kg b.w. (i.v.). The established LD50 values for the separated pure phospholipase A2 subunit are higher – 10.0–13.0 mg/kg b.w (i.p.) and 2.2–3.0 mg/kg b.w. (i.v.), i.e. the individual phospholipase A2 subunit displays less toxic activity than vipoxin, contrary to the data published in the literature. The reconstituted vipoxin complex (obtained after preliminary incubation of pure separated phospholipase A2 and acidic component showed enzyme activity and toxicity comparable to that of the native vipoxin complex. Addition of acidic component to the phospholipase A2 subunit showed a positive effect on the enzymatic activity, reaching maximal enzyme reaction rate of acidic component to phospholipase A2 molar ratio of 0.8:1 on using 4-nitro-3-octanoyloxy-benzoic acid as substrate. For the first time we showed that the acidic subunit was absolutely required for the toxic activity of vipoxin. Based on the obtained results, we assume that the function of the acidic component is to stabilize the neurotoxin's quaternary structure, required for its toxic and enzymatic activities, similarly to the role of the acidic component of crotoxin.

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Acute toxicity of vipoxin and its components: is the acidic component an "inhibitor" of PLA2 toxicity?

Complexes of Fe(III), Co(II), Ni(II) and Cu(II) with a tetraaza [14]annulene derivative were synthesized and their structures studied by means of IR, EPR, magnetochemical and 57Fe-Mossbauer scectroscopy.

Metal Complexes with a Tetraaza[14]Annulene Derivative

The structures of N-(4-benzalaniline)-15-crown-5 and N-(4'-benzalaniline)-15-crown-5 and their Li + , Na + , K + , Be 2+ , Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ complexes are optimized using ab initio and DFT methods. It was found that in all cases the M n+ ―N distances (n = 1, 2) are longer than the average M n+ ―O ones in the corresponding complexes and the metal― nitrogen distances in the alkali metal complexes are longer than these in alkaline earth ones. The Li + , Na + , Mg 2+ and Ca 2+ cations fit to cavity size of the crown while the K + , Sr 2+ and Ba 2+ cations, whose size is greater than the diameter of the macrocycle cavity, protrude from the macrocycle. In all cases the conformation of the crown ether does not change except the Be 2+ complex, where the conformation of the macrocycle is strongly deformed.

Ab initio and DFT study of the structure of metal ion complexes with N-benzalaniline-15-crown-5

SalNa (sodium salinomycin) reacts with divalent transition metal ions of Co(II), Ni(II), Cu(II) and Zn(II) to produce novel compounds characterized by various spectroscopic methods. The interaction of metal (II) ions with SalNa results in the formation of mononuclear complexes of a general composition of (M(Sal)2·(H2O)2) nH2O (n = 0 or 2) where the divalent cations replace Na + ions from the cavity of initial compound. The new compounds (disalinomycinates) possess an enhanced antibacterial activity against Gram-positive microorganisms as compared to both SalNa and SalH (salinomycinic acid), respectively. The metal (II) complexes manifest strong concentration dependent cytotoxic effect in experiments using human leukemia cell lines. The complexes of Co(II) and Cu(II) proved to exert superior activity as compared to the Ni(II) and Zn(II) analogues and are much more cytotoxic than SalNa and SalH. Further studies should be conducted to determine the therapeutic indexes of the new compounds.

Synthesis, Spectral Properties, Antibacterial and Antitumor Activity of Salinomycin Complexes with the Transition Metal Ions Co(II), Ni(II), Cu(II) and Zn(II)

Mariana Mitewa

Papers

Synthesis and Structure of a new Dimeric Pt(II)-Pt(III) Complex with o-Phthalic Acid

Acute toxicity of vipoxin and its components: is the acidic component an "inhibitor" of PLA2 toxicity?

Metal Complexes with a Tetraaza[14]Annulene Derivative

Ab initio and DFT study of the structure of metal ion complexes with N-benzalaniline-15-crown-5

Synthesis, Spectral Properties, Antibacterial and Antitumor Activity of Salinomycin Complexes with the Transition Metal Ions Co(II), Ni(II), Cu(II) and Zn(II)