Darvin Ivanov

Copper(II) complexes of (1-[isopropylamine]-3-[1-naphthyloxy]-2-propanol) (propranolol)

Abstract The complexation between copper(II) and the anti-hypertension drug propranolol (HL) was studied both in methanol and slightly alkaline aqueous media at M:HL = 1:2, and 1:4, respectively. Copper(II) forms two types of complexes—a violet one, CuL 2 .2HL with mono- and bifunctionally bonded ligands, and a green one, of dimeric type, Cu 2 L 2 Cl 2 with propranolol, coordinated through its nitrogen and oxygen atoms with alkoxide bridges. The content and structure of the complexes were studied using UV-VIS, IR and EPR spectra, and magnetochemical and elemental analysis data. The stability constants β 1 and β 2 of the complexes CuL + and CuL + were determined in 50% methanol.

Complexes of copper(II) with the β-blocker atenolol

Mono- and binuclear copper(II) complexes with atenolol (HAt) can be obtained, depending on the reaction conditions. The mononuclear violet complex cation has the general formula Cu(HAt)42+ with an elongated octahedral geometry. The two ligands in the equatorial plane are bound in a bidentate fashion through the hydroxyl oxygen and amino nitrogen, while the other two atenolol molecules in axial position are coordinated in a monodentate way. The binuclear green complex Cu2At2Cl2, is neutral, where atenolol acts as a bidentate (O−, NH) bridging ligand. The bridge between the two Cu atoms is realized by the deprotonated oxygen of the alcohol group.

Copper(II) complexes of the beta-blocker pindolol: properties, structure, biological activity.

The complex formation between copper(II) and the antihypertensive drug pindolol (HPin) was studied both in aqueous and methanolic media. Two complexes are formed at different metal-to-ligand molar ratios. The mononuclear complex Cu(Pin)2(HPin)2 contains two ligands in an anionic bidentate form and two - in a neutral form bound monodentately. The second complex Cu2Pin2Cl2 is dinuclear and its structure was determined by X-ray diffraction. The compound crystallizes in the monoclinic group C2/c with cell components a = 14.4998(13)Å, b = 18.511(2)Å, c = 14.2982(13)Å, α=90xa0°, β=109.556(2)°, γ=90xa0° and Z = 12 at 293K. A pharmacological study on the influence of pindolol and its mononuclear complex on the heart rate of rats was performed. The complex is more active and has a longer effect in comparison with the pure non-coordinated pindolol in equitoxic doses.

Platinum Complexes with 5-Methyl-5(4-pyridyl)hydantoin and Its 3-Methyl Derivatives: Synthesis and Cytotoxic Activity - Quantitative Structure-Activity Relationships

3,5‐Dimethyl‐5‐(4‐pyridyl)hydantoin (L) and its platinum(II) and platinum(IV) complexes with the general formula cis‐[PtL2X2]u2009·u2009n H2O and [PtL2Cl4], where Xuf8feCl, I and nu2009=u20092‐4 were synthesized. A new Pt(IV) complex with 5‐methyl‐5‐(4‐pyridyl)hydantoin (L′) with the formula cis‐[Pt(L′)2Cl2(OH)2]u2009·u20095 H2O was also synthesized. The novel compounds were characterized by elemental analysis, IR, 1H‐, 13C‐, 195Pt‐NMR spectra and molar conductivity. The cytotoxic effects of these complexes were examined on three human tumor cell lines by MTT‐dye reduction assay. These four new Pt(II) and Pt(IV) complexes and a set of another twelve Pt(II), Pt(IV), and Pd(II) complexes previously synthesized and tested were compiled and a QSAR model was derived in order to direct the further rational synthesis.

Synthesis, characterization and cytotoxic activity of new salicylaldehyde benzoylhydrazone derivatives as potential anti-proliferative agents.

Three new hydrazones, derivatives of salicylaldehyde benzoylhydrazone, were synthesized as potential anti-proliferative compounds. The structure of the new compounds was characterized by elemental and thermo-gravimetric analyses, IR, 1H and 13C-NMR spectroscopy and quantum chemical calculations. The cytotoxic effects of new hydrazones were examined on a wide spectrum of human tumor cell lines. The obtained results revealed that all compounds proved to be equipotent or moreactive than cisplatin, and far more activethan another utilized anticancer drug, melphalan. On the basis of IC50 values the compound 3-methoxy-salicylaldehyde isonicotinoylhydrazone (mSIH) was found to be the most active cytotoxic agent at all cell lines.

Interaction of 5-amino-1,3,4-thiadiazole-2-thiol and its violuric acid adduct with Pt(II) - crystals structures, spectroscopic properties and cytotoxic activity.

The coordination properties of Pt(II) with 5-amino-1,3,4-thiadiazole-2-thiol [CAS 2349-67-9] (L 1 ) and its novel violurate adduct (L 2 ), both in solution and in solid state, are studied by means of conventional IR-spectroscopy, single crystal X-ray diffraction and thermal methods. The complex compounds of L 1 and L 2 , with general formulas [Pt(C2H2N3S2)2] and [Pt(C6H4N6S2O3)(Cl)]Cl respectively, are obtained. Quantum chemical calculations of the ligands are performed with a view to obtain electronic structure and optical properties of the ligands L 1 and L 2 , respectively. The cell viability of the ligands and metal complexes on a panel of human tumor cell lines is evaluated.

Pt(II) complexes of 4-amino-4H-1,2,4-triazole

The coordination ability of 4-amino-4H-1,2,4-triazole with Pt(II), both in solution and solid states, is elucidated by conventional and linear-polarized IR spectroscopy of oriented colloid suspensions in nematic host, 1H- and 13C-NMR, UV-Vis spectroscopy, mass spectrometry (ESI and FAB), TGV, and DSC methods. The interpretation of the spectroscopic characteristics of corresponding metal complexes is obtained by comparison with free 4-amino-4H-1,2,4-triazole. In addition, quantum chemical calculations of the last compound are performed to obtain data for electronic structures and optical properties of the ligand, thus supporting the experimental elucidation. The evaluation of the cell viability on a panel of human tumor cell lines is made. The new Pt(II) complexes exerted cytotoxic effects in a concentration-dependent manner.

Synthesis, DFT calculations and characterisation of new mixed Pt(II) complexes with 3-thiolanespiro-5′-hydantoin and 4-thio-1H-tetrahydropyranspiro-5′-hydantoin

Cisplatin is an anticancer drug widely used in the treatment of a wide range of solid tumours (head and neck, lung, bladder etc.), testicular and ovarian cancers. Because of its severe toxicity profile and spontaneous development of drug resistance in tumours, a number of Pt(II) complexes have been synthesised and tested for anti-tumour activity. Some of the investigations have focused on using ligands bearing donor atoms other than N (e.g., S, P, O). Two new mixed Pt(II) complexes of the general formula cis-[Pt(NH3)LCl2] where L is 3-thiolanespiro-5′-hydantoin and 4-thio-1H-tetrahydropyranspiro-5′-hydantom were synthesised. The complexes were studied by elemental analysis, melting points, IR and 1H NMR spectra. The hybrid DFT calculations were used for optimisation of the structure geometries of the ligands III, IV and their Pt(II) complexes V and VI. The structural parameters so calculated, such as bond lengths and angles, are in good agreement with the experimental data for similar hydantoins and their platinum complexes. The results showed that the geometries of complexes V and VI are plane square and the bounding of ligands III and IV with platinum ions is effected by the sulphur atom from the cyclic ring. The complexes thus obtained were chemically examined in comparison with previously synthesised and published complexes of the general formula cis-[PtL2Cl2] (VII and VIII) with the same ligands. The new compounds V and VI, as well as the previously investigated complexes (VII and VIII), were analysed for cytotoxicity in vitro on SKW-3 and HL-60 human tumour cell lines. The results showed that all the complexes exerted concentration-dependent anti-proliferative activity.

Platinum(IV) complexes with some derivatives of 5-methyl-5-(4-pyridyl) hydantoin. Synthesis, study and comparative pharmacological investigation.

3 Pt(IV) complexes with 3-ethyl-5-methyl-5-(4-pyridyl)hydantoin (4), 3-propyl-5-methyl-5-(4-pyridyl)hydantoin (5) and 3-benzyl-5-methyl-5-(4-pyridyl)hydantoin (6) with general formulae cis-[Pt(L)2Cl4] were synthesized. The novel compounds were characterized by elemental analysis, IR, 1H, 13C, NMR spectra in solid state and in solution. The studies showed that the ligands coordinate to the platinum ions in a monodentate manner through the nitrogen atom from the pyridine ring. The cytotoxic activity in vitro of newly synthesized complexes as well as their previously prepared analogous of Pt(IV) with other derivatives like 3-amino-5-methyl-5-(4-pyridyl)hydantoin (1), 5-methyl-5-(4-pyridyl)hydantoin (2), 3,5-dimethyl-5-(4-pyridyl)hydantoin (3) was screened against a panel of human tumor cell lines. The tested compounds displayed cytotoxic activity which was invariably superior with the Pt(IV) complex with 3-benzyl-5-methyl-5-(4-pyridyl)hydantoin (6) causing 50% inhibition of cellular viability at micromolar concentration, though the activity of the other studied Pt(IV) complexes proved to greatly decrease in the order 5-4-3-2-1.

Copper(II) complexes of the antihypertensive drug nadolol

The complexation of the non-selective β-blocker nadolol, HL, 1 with copper(II) leads to formation of mono-and dinuclear complexes depending mainly on the metal-to-ligand molar ratio. The mononuclear violet complex CuL2·2Solv, 2, was obtained in a soluble form at metal-to-ligand molar ratio Cu(II): HL ≤ 1: 10 in methanolic or slightly alkaline aqueous solutions. The dinuclear green complex Cu2L2Cl2·H2O, 3 was synthesized at Cu(II): HL ≥ 1: 2 molar ratio in methanolic solutions. The complexes were studied using spectral (UV-Vis, FT-IR, EPR), magnetochemical, thermogravimetric methods and elemental analysis. In the complexes nadolol acts as a monoanionic bidentate ligand coordinated to copper(II) through the NH-and the deprotonated OH-groups of its aminoalcohol fragment.