Formula Cis Research Articles

Synthesis, structure and physicochemical properties of the boron rich PtII complexes [(CN)2dppPtCl(CBT)] and [(CN)2dppPt(CBT)2] (CBT = m-carborane-1-thiolate)

The present report deals with the synthesis of the two PtII complexes of respective formula cis-[(CN)2dppPtCl(CBT)]ˑ0.5(CH3)2CO and cis-[(CN)2dppPt(CBT)2] (dpp = 2,3-di(2-pyridyl)pyrazine; CBT = m-carborane-1-thiolate anion) the structure of both of them elucidated by single-crystal X-ray work and further examined by IR spectral behavior. These “low-molecular weight” mono- and bis-CBT derivatives may represent members of the restricted area of potential anticancer agents in BNCT (boron neutron capture therapy). Although insoluble in water, these new species are enough soluble in organic low-donor solvents like DMSO, CH3CN, THF, and solution studies in these solvents have allowed their physicochemical characterization by UV–visible and NMR measurements. Of relevant interest is the observed absorption present in the UV–visible spectrum of both species in the three solvents positioned in the region 400–500 nm, intimately related to the presence of CBT in both the cis-arranged species, similarly to what observed in previously published strictly related analogs.

Ligand-Centered Photocatalytic Hydrogen Production in an Axially Capped Rh2(II,II) Paddlewheel Complex with Red Light.

A new series of Rh2(II,II) complexes with the formula cis-[Rh2(DTolF)2(bpnp)(L)]2+, where bpnp = 2,7-bis(2-pyridyl)-1,8-naphthyridine, DTolF = N,N'-di(p-tolyl) formamidinate, and L = pdz (pyridazine; 2), cinn (cinnoline; 3), and bncn (benzo[c]cinnoline; 4), were synthesized from the precursor cis-[Rh2(DTolF)2(bpnp)(CH3CN)2]2+ (1). The first reduction couple in 2-4 is localized on the bpnp ligand at approximately -0.52 V vs Ag/AgCl in CH3CN (0.1 M TBAPF6), followed by reduction of the corresponding diazine ligand. Complex 1 exhibits a Rh2(δ*)/DTolF → bpnp(π*) metal/ligand-to-ligand charge-transfer (1ML-LCT) absorption with a maximum at 767 nm (ε = 1800 M-1 cm-1). This transition is also present in the spectra of 2-4, overlaid with the Rh2(δ*)/DTolF → L(π*) 1ML-LCT bands at 516 nm in 2 (L = pdz), 640 nm in 3 (L = cinn), and 721 nm in 4 (L = bncn). Complexes 2 and 3 exhibit Rh2(δ*)/DTolF → bpnp 3ML-LCT excited states with lifetimes, τ, of 3 and 5 ns, respectively, in CH3CN, whereas the lowest energy 3ML-LCT state in 4 is Rh2(δ*)/DTolF → bncn in nature with τ = 1 ns. Irradiation of 4 with 670 nm light in DMF in the presence of 0.1 M TsOH (p-toluene sulfonic acid) and 30 mM BNAH (1-benzyl-1,4-dihydronicotinamide) results in the production of H2 with a turnover number (TON) of 16 over 24 h. The axial capping of the Rh2(II,II) bimetallic core with the bpnp ligand prevents the formation of an Rh-H hydride intermediate. These results show that the observed photocatalytic reactivity is localized on the bncn ligand, representing the first example of ligand-centered H2 production.

Enantiomeric Complexes Based on Ruthenium(III) and 2,2'-Biimidazole: X-ray Structure and Magnetic Properties.

We have prepared and characterized two Ru(III) compounds based on the 2,2'-biimidazole (H2biim) ligand, namely, a single complex of formula cis-[RuCl2(H2biim)2]Cl·4H2O (1) and a racemic mixture of formula {cis-[RuCl2(H2biim)2]Cl}2·4H2O (2), which contains 50% of Ru(III) complex 1. Both compounds crystallize in the monoclinic system with space groups C2 and P21 for 1 and 2, respectively. These complexes exhibit the metal ion bonded to four nitrogen atoms from two H2biim molecules and two chloride ions, which balance part of the positive charges in a distorted octahedral geometry. Significant differences are observed in their crystal packing, which leads to the observation of differences in their respective magnetic behaviors. Despite having imidazole rings in both compounds, π-π stacking interactions occur only in the crystal structure of 2, and the shortest intermolecular Ru···Ru separation in 2 is consequently shorter than that in 1. Variable-temperature dc magnetic susceptibility measurements performed on polycrystalline samples of 1 and 2 reveal different magnetic behaviors at low temperatures: while 1 behaves pretty much as a magnetically isolated mononuclear Ru(III) complex with S = 1/2, 2 exhibits the behavior of an antiferromagnetically coupled system with S = 0 and a maximum in the magnetic susceptibility curve at approximately 3.0 K.

Luminescent Platinum Complexes with π-Extended Aryl Acetylide Ligands Supported by Isocyanides or Acyclic Diaminocarbenes.

In this work, we present a series of luminescent platinum acetylide complexes with acetylides that are electronically modified and/or π-extended. Six isocyanide-supported complexes with the general formula cis-[Pt(CNAr)2(C≡CR)2] and six acyclic diaminocarbene (ADC) complexes of the form trans-[Pt(ADC)2(C≡CR)2], all using the same five acetylide ligands, are described. The compounds are characterized by multinuclear NMR, FT-IR, and single-crystal X-ray diffraction. In most cases, the phosphorescence arises from an acetylide-centered 3(π → π*) excited state, although in one of the isocyanide compounds there is evidence for a charge-transfer excited state. The photoluminescence wavelength depends strongly on the substitution pattern and extent of the π conjugation on the acetylide, with maxima spanning the range of ca. 460-540 nm. Most photoluminescence lifetimes are long, beyond 50 μs, and quantum yields are low to moderate, 0.043-0.27. The photoluminescence quantum yields and lifetimes in these compounds do not systematically improve in the ADC complexes compared to the isocyanide versions, suggesting the neutral ligand σ-donor character does not play a large role in the excited-state dynamics when the triplet excited state is delocalized over a large π system.

New ruthenium(II) complexes with cyclic thio- and semicarbazone: evaluation of cytotoxicity and effects on cell migration and apoptosis of lung cancer cells.

We describe the synthesis, physicochemical characterization, and in vitro antitumor assays of four novel analogous ruthenium(II) complexes with general formula cis-[RuII(N-L)(P-P)2]PF6, where P-P = bis(diphenylphosphine)methane (dppm, in complexes 1 and 2) or bis(diphenylphosphine)ethane (dppe, in complexes 3 and 4) and N-L = 5,6-diphenyl-4,5-dihydro-2H-[1,2,4]triazine-3-thione (Btsc, in complexes 1 and 3) or 5,6-diphenyltriazine-3-one (Bsc, in complexes 2 and 4). The data were consistent with cis arrangement of the biphosphine ligands. For the Btsc and Bsc ligands, the data pointed to monoanionic bidentate coordination to ruthenium(II) through N,S and N,O, respectively. Single-crystal X-ray diffraction showed that complex 1 crystallized in the monoclinic system, space group P21/c. Determination of the cytotoxicity profiles of complexes 1-4 gave SI values ranging from 1.19 to 3.50 against the human lung adenocarcinoma cell line A549 and the non-tumor lung cell line MRC-5. Although the molecular docking studies suggested that the interaction between DNA and complex 4 was energetically favorable, the experimental results showed that they interacted weakly. Overall, our results demonstrated that these novel ruthenium(II) complexes have interesting in vitro antitumor potential and this study may contribute to further studies in medicinal inorganic chemistry.

A Combined Experimental and Theoretical Investigation of Oxidation Catalysis by cis-[VIV(O)(Cl/F)(N4)]+ Species Mimicking the Active Center of Metal-Enzymes.

Reaction of VIVOCl2 with the nonplanar tetradentate N4 bis-quinoline ligands yielded four oxidovanadium(IV) compounds of the general formula cis-[VIV(O)(Cl)(N4)]Cl. Sequential treatment of the two nonmethylated N4 oxidovanadium(IV) compounds with KF and NaClO4 resulted in the isolation of the species with the general formula cis-[VIV(O)(F)(N4)]ClO4. In marked contrast, the methylated N4 oxidovanadium(IV) derivatives are inert toward KF reaction due to steric hindrance, as evidenced by EPR and theoretical calculations. The oxidovanadium(IV) compounds were characterized by single-crystal X-ray structure analysis, cw EPR spectroscopy, and magnetic susceptibility. The crystallographic characterization showed that the vanadium compounds have a highly distorted octahedral coordination environment and the d(VIV-F) = 1.834(1) Å is the shortest to be reported for (oxido)(fluorido)vanadium(IV) compounds. The experimental EPR parameters of the VIVO2+ species deviate from the ones calculated by the empirical additivity relationship and can be attributed to the axial donor atom trans to the oxido group and the distorted VIV coordination environment. The vanadium compounds act as catalysts toward alkane oxidation by aqueous H2O2 with moderate ΤΟΝ up to 293 and product yields of up to 29% (based on alkane); the vanadium(IV) is oxidized to vanadium(V), and the ligands remain bound to the vanadium atom during the catalysis, as determined by 51V and 1H NMR spectroscopies. The cw X-band EPR studies proved that the mechanism of the catalytic reaction is through hydroxyl radicals. The chloride substitution reaction in the cis-[VIV(O)(Cl)(N4)]+ species by fluoride and the mechanism of the alkane oxidation were studied by DFT calculations.

Hydrophilic platinum(II) complexes containing 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine: Spectroscopic and in vitro cytotoxic characterization

Mononuclear platinum(II) complexes with 5,7-methyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) of the general formula cis-[Pt(X)2(dmtp)2], where X - acetate (1), trichloroacetate (2), trifluoroacetate (3), nitrate (4) have been synthesized and characterized by multinuclear magnetic resonance (1H, 13C, 15N, 195Pt) and infrared spectroscopy methods. Spectroscopic parameters indicated the presence of the PtO2N2 chromophore system with two monodentate N(3)-bonded 5,7-methyl-1,2,4-triazolo[1,5-a]pyrimidines, and two monodentate O-donor ligands (carboxylate or nitrate).A cytotoxicity assay of hydrophilic platinum(II) complexes (1–4) against three human tumour cell lines A549 (non-small cell lung carcinoma), T47D (breast cancer), HT-29 (colon adenocarcinoma), and normal murine embryonic fibroblast cells (BALB/3T3) was performed.Considering the cytotoxic parameters of the studied complexes, the best in vitro results against the human breast tumour cells (T47D) were found for cis-[Pt(OOCCCl3)2(dmtp)2] although all the tested complexes (except complex (4)) exhibited moderate in vitro activity.

Study on the interaction of K[PtCl3(L)] (L: safrole, methyleugenol, isopropyl eugenoxyacetate and piperidine)] with some heterocyclic bidentate amines

AbstractThe interactions between K[PtCl3(L)] (L: safrole/1a, methyleugenol/1b, isopropyl eugenoxyacetate/1c, piperidine/1d) and heterocyclic bidentate amines (1,10‐phenalthroline/Phen, 2,2’‐bipyridine/Bpy, 4,4’‐dimethyl‐2,2’‐bipyridine/MeBpy, and 8‐aminoquinoline/NH2Q) were investigated for the first time. The results show that the amines readily replace the L ligand, the arylolefin or piperidine, to form complexes of the formula cis‐[PtCl2(amine)] (amine: Phen/2, Bpy/3, MeBpy/4 and NH2Q/5) in very high yields (90‐95 %). The structures of 2‐5 were analyzed by Pt percentage, IR spectroscopy, and also by ESI‐MS, 1H NMR spectroscopy for 5. The result of testing in vitro cytotoxicity of complex 5 against Hep G2, RD, MCF‐7 and Fl human cancer cell lines indicates that complex 5 exhibits greater activity against RD cell line in comparison to cisplatin with IC50 value of 6.96 μg/ml.

Synthesis, Characterization, and Water Oxidation Activity of Isomeric Ru Complexes.

The synthesis and characterization of the isomeric ruthenium complexes with the general formula cis- and trans-[Ru(trpy)(qc)X]n+ (trpy is 2,2':6',2″-terpyridine, qc is 8-quinolinecarboxylate, cis-1 and trans-1, X = Cl, n = 0; cis-2 and trans-2, X=OH2, n = 1) with respect to the relative disposition of the carboxylate and X ligands are reported. For comparison purposes, another set of ruthenium complexes with general formula cis- and trans-[Ru(trpy)(pic)(OH2)]+ (pic is 2-picolinate (cis-3, trans-3)) have been prepared. The complexes with a qc ligand show a more distorted geometry compared to the complexes with a pic ligand. In all of the cases, the trans isomers show lower potential values for all of the redox couples relative to the cis isomers. Complexes cis-2 and trans-2 with six-member chelate rings show higher catalytic activity than cis-3 and trans-3. Overall, it was shown that the electronic perturbation to the metal center exerted by different orientation and geometry of the ligands significantly influences both redox properties and catalytic performance.

Synthesis and stability of the dirhenium(III) cluster compounds with isoleucine, serine and proline in aqueous solutions

The previously developed methods for the synthesis of cis-tetrachlorodi--carboxylates of dirhenium(III) were modified, due to which the derivatives of Re26+ with proteinogenic amino acids (AA) isoleucine, serine and proline were synthesized for the first time. The composition and structure of these substances with the general formula cis-[Re2(АA)2Cl4(CH3CN)2]Cl2 were confirmed by elemental analysis, electron adsorption and IR spectroscopy. The presence of a characteristic peak, which corresponds to the *-electronic transition of the Re–Re quadruple bond for compounds with the cis-arrangement of two bridging-coordinated carboxylate groups in the ligand environment of the Re26+ cluster, was showed by using the data on the electronic absorption spectra of solutions of the synthesized compounds. The IR spectrum contains an intense, weakly split band in the region of 1466–1458 cm–1, which is attributed to the s(CO) coordinated carboxyl group and indicates its bridging coordination to the binuclear Re26+ fragment. The spectra exhibited the presence of bands of stretching (NH3+) and bending vibrations (NH3+) of protonated amino groups in complex compounds of isoleucine and serine and the presence of bands of stretching (NH2+) and bending vibrations (NH2+) of the protonated imino group of proline. The stability of the prepared complex compounds in aqueous solutions was investigated. It is shown that the hydrolysis of the synthesized substances occurs within 9–14 days with a decrease in the pH of the reaction solution due to a gradual replacement of labile chloride ligands by OH–-groups at the first stages of interaction with water. The resistance to hydrolysis is an important parameter of biologically active substances; the determination of the resistance to hydrolysis will expand understanding of the possible mechanisms of their specific biological activity.

New Pt(II) complexes with 3’-methyl tetrahydro-4H-thiopyranspiro-5’-hydantoin: synthesis, theoretical and cytotoxic investigation

Three new platinum complexes with chemical formulas cis-[PtL2Cl2], cis-[PtL2I2] and cis-[PtL(NH3)Cl2], where L is 3’-methyl-4-thio-1H-tetrahydropyranspiro-5’-hydantoin were synthesized and studied. The spectral and theoretical investigations proved that ligand coordinates through sulfur atom from tetrahydrothiopyrane fragment by monodentate manner with platinum ion. The newly synthesized compounds were tested for cytotoxic activity in vitro against four human tumor cell lines using MTT dye-reduction assay for cell viability. The tested compounds displayed cytotoxic effects in a concentration-dependent manner. Complex 2 as well as complex 3 have similar cytotoxicity to that of the prototype drug cisplatin on colon adenocarcinoma model HT-29.

1,2,4-triazole-derived N-heterocyclic carbene complexes of platinum(II) as catalysts for hydroamination reactions and active anticancer agents

A series of five platinum(II) complexes of 1,2,4-triazole derived N-heterocylcic carbenes (R-tazy) with generic formula cis-[PtCl2(R-tazy)(DMSO)] (DMSO = dimethyl sulfoxide) have been successfully synthesized. The complexes feature the carbenes with the same benzyl wingtip, but are differed by their N-4 substituent (R = isopropyl (1), cyclohexyl (2), phenyl (3), mesityl (4) and 2,6-diisopropylphenyl (5)). The two new compounds 1 and 2 were characterized by means of multinuclear (1H, 13C{1H}) magnetic resonance spectroscopy, mass spectrometry, elemental analysis and single crystal X-ray diffraction (for 2). The hindered rotations of the benzyl and κ-S-dimethyl sulfoxide were elucidated using NMR spectroscopy and rationalized with density functional theory (DFT) calculation. Notably, the five complexes were found active catalysts for intermolecular hydroamination of phenylacetylene using aromatic amines in the presence of silver(I) triflate additive. In addition, all the five complexes display high cytotoxicity toward human carcinoma in the mouth (KB), human breast carcinoma (MCF-7) and human colorectal carcinoma (HT-29) cell lines with IC50 concentration in the 3.0 ± 0.4–14.3 ± 1.3 μM range. Interestingly, compound 1 and 3 display lower cytotoxicity toward non-cancerous human embryonic kidney cell (HEK-293A).

Encapsulation of Dirhenium(III) Carboxylates into Zirconium Phosphate

Present work reports the synthesis of zirconium phosphate nanoparticles containing dirhenium(III) substance bis-dimethylsulfoxide-cis-tetrachlorodi-?-pivalatodirhenium(III) with formula cis-Re2(C(CH3)3COO)2Cl4?2DMSO (I) and q-zirconium phosphate with formula q-Zr(HPO4)2?6H2O (ZrP). The intercalation process was monitored by EAS. Due to the spectral characteristics of the quadruple bond the conclusion was made that the obtained intercalated compounds had cis-configuration of ligands around cluster dirhenium fragment. The proposed mechanism of intercalation includes the substitution of the axial ligands of I by phosphate groups of ZrP first on the surface of ZrP, than in the inner layers. Two received products of the intercalation were characterized by SEM, XRPD, FT-IR, TGA analysis witnessing about successful intercalation process. The formation of new phases with interlayer distances of 10.53 - 16.6 ? was found, the average size of obtained platelets was 100-200 nm.

Photophysics and ultrafast processes in rhenium(I) diimine dicarbonyls.

In this work, a series of nine Re(i) diimine dicarbonyl complexes of the general molecular formula cis-[Re(N^N)2(CO)2]+ (N^N are various 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) derivatives) were prepared and spectroscopically investigated to systematically evaluate the photophysical consequences of various substituents resident on the diimine ligands. These panchromatic absorbing chromophores were structurally characterized, evaluated for their electrochemical and spectroelectrochemical properties, and investigated using static and dynamic electronic absorption, photoluminescence (PL), and infrared spectroscopy from ultrafast to supra-nanosecond time scales. The ultrafast time-resolved infrared (TRIR) analysis was further supported by electronic structure calculations which characterized the changes within the two C[triple bond, length as m-dash]O vibrational modes upon formation of the metal-to-ligand charge transfer (MLCT) excited state. The MLCT excited state decay of this series of dicarbonyl molecules appears completely consistent with energy-gap law behavior, where the nonradiative decay rate constants increase logarithmically with decreasing excited state - ground state energy separation, except in anticipated cases where the substituents were phenyl or tert-butyl.

Mononuclear coordination compounds containing a pyrazole-based ligand: Syntheses, magnetism and acetylcholinesterase inhibition assays

A series of three pseudo-octahedral coordination compounds with general formula cis-[M(L)2(OH2)4], where M stands for FeII (1), CoII (2) or NiII (3), and HL is 5-amino-1-(benzo[d]thiazol-2-yl)-1H-pyrazole-4-carboxylic acid proligand was synthesized by slow diffusion methodology and thoroughly characterized by spectroscopic techniques, magnetic measurements and ab initio calculations. Single crystal X-ray diffraction data obtained for 1 and 2 revealed that the crystal packing is stabilized by a hydrogen bond network while X-ray powder pattern, Raman and IR spectra indicated that compounds 1 and 3 are isomorphic. Mössbauer spectra recorded at 3 and 300 K for 1 showed that the FeII ion is in its high spin state. Magnetic studies carried out for complexes 1–2 showed the key role played by the zero-field splitting and the experimental fit data were correlated and supported by CASSCF calculations. The activity of acetylcholinesterase enzyme was investigated towards L and 1–3 by using Elman’s methodology, affording inhibition rates of 20%, 56%, 35% and 36%, respectively.

A comparative study on cisplatin analogs containing 7-azaindole (7AIH) and its seven halogeno-derivatives: Vibrational spectra, DFT calculations and in vitro antiproliferative activity. Crystal and molecular structure of cis-[PtCl2(4Br7AIH)2]·DMF

Eight platinum(II) complexes of the general formula cis-[PtCl2(L)2] containing 7-azaindole (L = 7AIH) and its halogeno-derivatives: L = 3-chloro-7-azaindole (3Cl7AIH); 3-bromo-7-azaindole (3Br7AIH); 4-chloro-7-azaindole (4Cl7AIH); 4-bromo-7-azaindole (4Br7AIH); 5-bromo-7-azaindole (5Br7AIH); 3-bromo-4-chloro-7-azaindole (3Br4Cl7AIH) and 5-bromo-3-chloro-7-azaindole (5Br3Cl7AIH) were prepared. Two complexes, cis-[PtCl2(3Br4Cl7AIH)2] (2) and cis-[PtCl2(4Br7AIH)2]·DMF, are reported for the first time. Crystal structure of the latter compound has been determined with X-ray diffraction analysis (space group P43, with a = 14.775(2), c = 41.640(8) Å, V = 9090(3) Å3 and Z = 16). For all of these complexes, formation of the cis isomers in the solid state was confirmed by experimental vibrational (IR and Raman) spectroscopy combined with DFT calculations. A complete assignment of the IR and Raman spectra was made on the basis of the calculated potential energy distribution (PED). Stability of complex (2) in DMSO solution was investigated by FT-IR (ATR) spectroscopy. The in vitro antiproliferative activity of cis-[PtCl2(3Br4Cl7AIH)2], cis-[PtCl2(3Cl7AIH)2] and cis-[PtCl2(3Br7AIH)2] was evaluated on selected human cancer cell lines and towards normal mouse fibroblast cell line (BALB/3T3). All complexes are more toxic than cisplatin against Es-2 (ovarian cancer), LNCaP (prostate adenocarcinoma) and MCF7 (breast cancer). Moreover, complex (2) is significantly more active than the other complexes on A549 (lung carcinoma, IC50 = 3.9 μM). However, the three investigated Pt(II) complexes with 7-azaindoles have revealed higher cytotoxicity against a normal cell line (BALB/3T3), in comparison to cisplatin.

Molybdenum and rhenium carbonyl complexes containing thiolato ligands

The reaction of fac-[M(OTf)(CO)3(N–N)](M = Mn, Re; N–N = 2,2′-bipyridine, 1,10-phenanthroline) complexes with in situ generated LiSEt afforded immediately, in THF at low temperature, the corresponding mononuclear terminal thiolato complexes fac-[M(SEt)(CO)3(N–N)](1-2a,b). Using an analogous synthetic strategy, tungsten and molybdenum (II) alkyl- and arylthiolatos of formula cis-[M(SR)(η3-allyl)(CO)2(N–N)] (3-6a,b) have been obtained. Preliminary reactions of the more reactive molybdenum thiolato complexes towards dimethylacetylenedicarboxylate led to Z-alkenyl products (7a,b), resulting from the insertion of the organic unsaturated electrophile into the Mo–S bond. For each new type of compound, one representative has been characterized in the solid state by X-ray diffraction.

Carbonyl–heterobimetallic Ru(II)/Fe(II)–complexes containing polypyridyl ligands: Synthesis, characterization, cellular viability assays and interactions with biomolecules

This paper describes on the interaction studies of carbonyl heterobimetallic compounds of Ru(II)/Fe(II) containing polypyridyl ligands, with general formula ct–[RuCl(CO)(N–N)(dppf)]PF6, N–N = 1,10–phenanthroline (phen) 5; dipyrido[3,2–f:2′,3′–h]quinoxaline (dpq) 6; dipyrido[3,2–a:2′,3′–c]phenazine (dppz) 7; dipyrido[3,2–f:2′,3′–h]quinoxalino[2,3–b]quinoxaline (dpqQX) 8 and dppf = 1,1‘–bis(diphenylphosphino) ferrocene], with calf thymus DNA (ct–DNA) and bovine serum albumin (BSA). Also, it describes the cellular viability assays of these complexes in tumorigenic and non-tumorigenic cell lines. The carbonyl complexes 5–8 and their respective precursors with formula cis–[RuCl2(N–N)(dppf)], N–N = phen (1), dpq (2), dppz (3) and dpqQX (4), were characterized by elemental analysis and spectroscopic techniques (FTIR, UV–vis, 1H and 31P{1H} NMR). Also, a cyclic voltammetry study was performed for all complexes. The crystal structure of the complex 3 is presented and discussed. Spectrofluorimetric titrations shows spontaneous and strong interaction of 5–8 with BSA, through a static quenching mechanism, resulting in binding constants in the order of 104–106 L mol−1, at 310 K. Viscosity measurements and circular dichroism spectra prompts interactions of 5–8 with ct–DNA via non–classical intercalations or by an electrostatic pathway. MTT assays in breast tumor cells MDA–MB–231 and in non-tumorigenic cells MCF-10A and V79–4 cell lines revealed IC50 values ranging from 0.19 to 1.11 μmol L−1, 1.07–3.18 μmol L−1 and 1.29–3.85 μmol L−1 respectively, for complexes 5–8.

Improving of Anticancer Activity and Solubility of Cisplatin by Methylglycine and Methyl Amine Ligands Against Human Breast Adenocarcinoma Cell Line.

Methylglycine, also known sarcosine, is dramatically used in drug molecules and its metal complexes can interact to DNA and also do cleavage. Hence, to study the influence of methylglycine ligand on biological behavior of metal complexes, two water-soluble platinum (II) complexes with the formula cis-[Pt(NH3)2(CH3-gly)]NO3 and cis-[Pt(NH2-CH3)2(CH3-gly)]NO3 (where CH3-gly is methylglycine) have been synthesized and characterized by spectroscopic methods, molar conductivity measurements, and elemental analyzes. The anticancer activity of synthesized complexes was tested against human breast adenocarcinoma cell line of MCF7 using MTT assay and results showed excellent anticancer activity with Cc50 values of 126 and 292μM after 24h incubation time, for both complexes of cis-[Pt(NH3)2(CH3gly)]NO3 and cis-[Pt(NH2-CH3)2(CH3gly)]NO3, respectively. Also, the interaction between Pt(II) complexes with calf thymus DNA was extensively studied by means of absorption spectroscopy, fluorescence titration spectra displacement with ethidium bromide (EtBr), and circular dichroism studied in Tris-buffer. The obtained spectroscopic results revealed that two complexes can bind to highly polymerized calf thymus DNA cooperatively and denature at micromolar concentrations. The fluorescence data indicate that quenching effect for cis-[Pt(NH3)2(CH3gly)]NO3 (Ksv = 9.48mM-1) was higher than that of cis-[Pt(NH2-CH3)2(CH3gly)]NO3 (Ksv =1.98mM-1). These results were also confirmed by circular dichrosim spectra. Consequently, docking data showed that cis-[Pt(NH3)2(CH3gly)]NO3 with more interaction energy binds on DNA via groove binding which is more compatible with experimental results. Graphical Abstract ᅟ Two anticancer Pt(II) complexes, cis-[Pt(NH3)2(CH3gly)]NO3 and cis-[Pt(NH2-CH3)2(CH3gly)]NO3, have been synthesized and interacted with calf thymus DNA. Improving solubility of these compounds reduce side effects and increase anticancer activity against human breast cell line. Modes of binding have been studied by electronic absorption, fluorescence, and CD measurements. Results show that both Pt(II) complexes can interact to DNA via groove binding.

Thiocarbonyl-bound metallonitrosyl complexes with visible-light induced DNA cleavage and promising vasodilation activity

Nitric oxide has been involved in many key biological processes such as vasodilation, platelet aggregation, apoptosis, memory function, and this has drawn attention to the development of exogenous NO donors. Metallonitrosyl complexes are an important class of these compounds. Here, two new ruthenium nitrosyl complexes containing a thiocarbonyl ligand, with the formula cis-[Ru(phen)2(L)(NO)](PF6)3 (phen = phenantroline, L = thiourea or thiobenzamide), were synthesized and characterized by electronic spectroscopy, FTIR, NMR, mass spectrometry and voltammetric techniques. Theoretical calculations using Density Functional Theory (DFT) and Time-dependent Density Functional Theory (TD-DFT) were also used and further supported the characterizations of these complexes. An efficient release of nitric oxide by blue light was validated using a NO/HNO probe: 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, known as cPTIO. Interestingly, the complex containing thiourea cleaved DNA even in the dark, while both complexes showed great DNA photocleavage activity in blue light. This process might work mainly through NO and hydroxyl radical production. Additionally, these complexes showed promising vasodilator activity, whose mechanism of action was investigated using N-Nitro-l-arginine methyl ester hydrochloride (L-NAME) and 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and compared to sodium nitroprusside. Both compounds were indeed NO-mediated heme-dependent activators of soluble guanylate cyclase. Additionally, they did not show any significant cytotoxicity against cancer cell lines U87 and GBM02. Altogether, these results supported both complexes having potential pharmacological applications that deserve further studies.