Phen Ligands Research Articles

Effect of the replacement of tripodal 4N donors by two 2N chelators on the redox and cytotoxic activity of maltolato and deferipronato containing Co(III) complexes

Fourteen novel CoIII ternary complexes with the general formula [Co(4N)(2O)]X2 or [Co(2N)2(2O)]X2 where 4N = tris(2-aminoethyl)amine (tren) or tris(2-pyridylmethyl)amine (tpa); 2N = 1,10-phenantroline (phen), 2,2′-bipyridine (bipy), 1,2-diaminoethane (en) or 2-(aminomethyl)pyridine (ampy) and 2O = 1,2-dimethyl-3-hydroxy-4(1H)-pyridinone (dhpH), 3-hydroxy-2-methyl-4-pyrone (maltH) or 2-ethyl-3-hydroxy-4H-pyran-4-one (etmaltH) were synthesized, characterized and their redox features explored. Molecular structure of some selected [Co(2N)2(2O)](ClO4)2 (2N = phen, bipy, en; 2O = dhp, malt) or [Co(4N)(2O)](ClO4)2 (4N = tpa; 2O = etmalt) type complexes were assessed by X-ray diffraction and showed the expected octahedral geometry. Replacement of the 4N donor ligands by two 2N donor ligands resulted in the decrease of the cathodic peak potential of the complexes indicating easier reduction and allowing therefore the tailoring of the redox properties of the complexes. Screening of selected compounds against a human derived cancer cell line, HeLa, showed that, unlike the [Co(4N)(2O)]X2 derivatives, the complexes containing 2N = bipy or phen ligands have better anticancer activity than cisplatin or carboplatin.

Forty Years after the Discovery of Its Nucleolytic Activity: [Cu(phen)2 ]2+ Shows Unattended DNA Cleavage Activity upon Fluorination.

[Cu(phen)2]2+ (phen=1,10‐phenanthroline) is the first and still one of the most efficient artificial nucleases. In general, when the phen ligand is modified, the nucleolytic activity of its CuII complex is significantly reduced. This is most likely due to higher steric bulk of such ligands and thus lower affinity to DNA. CuII complexes with phen ligands having fluorinated substituents (F, CF3, SF5, SCF3) surprisingly showed excellent DNA cleavage activity—in contrast to the unsubstituted [Cu(phen)2]2+—in the absence of the otherwise required classical, bioabundant external reducing agents like thiols or ascorbate. This nucleolytic activity correlates well with the half‐wave potentials E 1/2 of the complexes. Cancer cell studies show cytotoxic effects of all complexes with fluorinated ligands in the low μm range, whereas they were less toxic towards healthy cells (fibroblasts).

Discrimination of Methanol from Ethanol in Gasoline Using a Membrane-type Surface Stress Sensor Coated with Copper(I) Complex

Abstract We successfully fabricated a novel sensing platform, a Membrane-type Surface stress Sensor (MSS) coated with copper(I) complex bearing phen and BINAP ligands, [Cu(phen)((±)-BINAP)]PF6 (1, phen = 1,10-phenanthroline, BINAP = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl), for specific molecular sensing. Based on the transduction of mechanical stresses derived from sorption-induced deformation of Cu(I) complex, the detection performance of various volatile organic compounds (VOCs) has been investigated. The fabricated sensor devices showed selective responses to methanol over a wide range of VOCs. In addition, distinct MSS signals upon exposure to methanol were observed for mixing samples of methanol in n-hexane and gasoline with clear discrimination of ethanol mixtures. In fact, gasoline vapor with 1% methanol exhibited much higher MSS responses than 20% ethanol containing gasoline samples. Methanol contamination in gasoline and related petroleum samples is a world-wide common problem in the automobile and fuel sectors where detection of methanol contaminants with portable devices by easy procedures is required. The current research results will contribute to fulfilling these social demands.

Binuclear Gadolinium(III) Pivalates with 4,7‐Diphenyl‐1,10‐Phenanthroline: Synthesis, Structure, Thermal Behavior, Magnetic and Photoluminescence Properties

AbstractComplexes [Gd2(piv)6(bath)2]⋅2EtOH (1a⋅2EtOH), [Gd2(piv)6(bath)2]⋅1.5EtOH⋅0.5H2O (1b⋅1.5EtOH⋅0.5H2O), and [Gd2(piv)6(bath)2]⋅H2O (1c⋅H2O), where piv is (CH3)3CCO2− and bath is 4,7‐diphenyl‐1,10‐phenanthroline, which have different molecular and crystal structures, were synthesized and studied by X‐ray diffraction. A unique feature of polymorphs 1a, 1b, and 1c is that they exhibit first‐order phase transitions, namely, structural phase transitions, or melting before thermal decomposition. Magneto‐structural data for binuclear gadolinium pivalates with bath (1), bpy (2), phen (3), and Hpiv (4) ligands and the polymeric complex [Gd(piv)3]n (5) are presented. The complexes were characterized by ESR spectroscopy. The energies of the excited singlet S1 and triplet T1 states of the bath ligand in carboxylates 1a⋅2EtOH, 1b⋅1.5EtOH⋅0.5H2O, and 1c⋅H2O were determined.

Synthesis, characterization and in vitro cytotoxicity studies of novel Cu(II) complex containing zonisamide drug: DNA interaction by multi spectroscopic and molecular docking methods

In this study, the Cu(II) complex with Zonisamide (ZNS) and 1, 10-Phenanthroline (Phen) ligands as an anticancer metallodrug was synthesized and characterized successfully by FT-IR, mass spectrometry, TGA, XPS, AAS, CHNSO, magnetic susceptibility and electrical conductivity. The interaction of Cu(II) complex with DNA was explored through a multi-spectroscopic approach such as fluorescence, UV-vis spectrophotometry, CD spectroscopy, and viscosity measurements. Molecular docking simulation was carried out to gain a deeper insight into the target site of DNA which interacted with the mentioned complex. The competitive binding tests with Hoechst 33258 showed that [CuCl2(ZNS)(Phen)EtOH].H2O can bind to the groove site of DNA. The calculated thermodynamic parameters, ΔS° = +201.15 J mol−1K−1 and ΔH° = +41.32 kJ mol−1 confirm that the hydrophobic forces and hydrogen bonding play an essential role in the binding process. The experimental and molecular modeling results demonstrate that the Cu(II) complex binds to DNA through major groove binding. Moreover, the in vitro cytotoxic effects of [CuCl2(ZNS)(Phen)EtOH].H2O against B92 cancer cell lines showed better activity in Cu(II) complex in comparison to free ZNS. Therefore, [CuCl2(ZNS)(Phen)EtOH].H2O can open a new horizon in the treatment of glioma cancer by ZNS metallodrugs. Communicated by Ramaswamy H. Sarma

Influence of substituents in 1,10-phenanthroline on the structural and photophysical properties of W(CO)4(1,10-phenanthroline-type) complexes

In this work, methyl and phenyl substituents were introduced in the 2,9- and 4,7-positions of the phen ligand in order to study its impact on the structural and photophysical properties of [W(CO)4(phen-type)] complexes [phen-type = 4,7-dimethyl-1,10-phenanthroline (4,7-DMPhen); 4,7-diphenyl-1,10-phenanthroline (BPhen), and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)]. Crystallographic analysis of these complexes allows to investigate the correlation between the geometrical parameters with their photophysical properties measured by steady-state and time-resolved spectroscopies. The (OC)eq–W–(CO)eq angle is the most significantly influenced geometrical parameter by the substituents, showing values of 92.5°, 90.2°, and 81.2° for [W(CO)4(4,7-DMPhen)], [W(CO)4(BPhen)], and [W(CO)4(BCP)], respectively. The smallest angle observed for [W(CO)4(BCP)] is attributed to a steric repulsion exerted by the methyl groups to the equatorial carbonyls. Remarkably, a smaller OCeq–W–COeq angle favors the High-Energy (HE) emission band, as evidenced in the photoluminescence (PL) spectra of [W(CO)4(BCP)]. Conversely, a greater angle favors the Low-Energy (LE) emission band, as observed in the PL spectra of [W(CO)4(4,7-DMPhen)] and [W(CO)4(BPhen)]. The PL lifetime of the LE emission band becomes shorter when decreasing the (OC)eq–W–(CO)eq angle. Furthermore, the absorption feature was affected by the 2,9-dimethyl substituents, showing greater contribution from the high-energy shoulder on the visible absorption band. This study shows that the perturbation of the (OC)eq–W–(CO)eq angle induced by the substituents in the phen ligand influences on the photophysical properties of [W(CO)4(phen-type)] complexes.

A Two-Step Catalytic Cycle for the Acceptorless Dehydrogenation of Ethane by Group 10 Metal Complexes: Role of the Metal in Reactivity and Selectivity

Acceptorless dehydrogenation of ethane was achieved in the gas phase via a two-step catalytic cycle involving ternary cationic metal hydrides, [(phen)M(H)]+, 1, and metal ethides, [(phen)M(CH2CH3)]+, 2, (where M = Ni, Pd, or Pt, and phen = 1,10-phenanthroline). Species 1 and 2 were generated and their reactivity studied in a quadrupole ion trap mass spectrometer. It was found that 1 readily reacted with ethane releasing H2 and forming 2, with the relative reactivity being Pt > Ni ≫ Pd. Density functional theory (DFT) calculations for this metathesis reaction agree with the experimental reactivity order. Species 2 can in turn be converted into 1 and release ethylene when sufficient energy is supplied via collision-induced dissociation. DFT calculations also provided insight into competing side reactions (e.g., dehydrogenation of 2 and formation of protonated phen ligand) that become competitive during this endothermic step. The catalytic cycle can be repeated in the mass spectrometer several times. Multiple entry points into the cycle have been identified and discussed.

Novel rare earth coordination polymers with greatly enhanced fluorescence by synergistic effect of carboxyl-functionalized poly(arylene ether nitrile) and 1,10-phenanthroline

A series of novel rare earth coordination polymers were synthesized using carboxyl-functionalized poly(arylene ether nitrile) (CPEN) as a macromolecular ligand, europium and terbium ions as central ions, and 1,10-phenanthroline (Phen) as a small-molecule coligand. The experimental results confirmed that the rare earth ions were simultaneously coordinated with the carboxyl groups of CPEN and Phen in the ternary coordination polymers. It was worth noting that the fluorescence intensity of the ternary coordination polymers was greatly enhanced by the synergistic coordination of CPEN and Phen, which benefited from the efficient energy transfer from CPEN and Phen ligands to rare earth ions. Furthermore, it was found that the fluorescence intensity increased with increasing Eu3+ ion content in ternary coordination polymer, and the critical Eu3+ ion concentration when fluorescence quenching occurred was as high as 11.5 wt%. As a result, the ternary coordination polymers exhibit intense, characteristic red (Eu3+) and green (Tb3+) emission under UV excitation both in the powder and film state. In addition, the rare earth coordination polymers showed a high glass transition temperature (251 °C) and high thermal stability, offering great potential applications as light-emitting devices, fluorescence detectors and sensors in special environments (e.g., high-temperature environment, extreme environments).

Temperature-influenced M2L and M2L2 molecular metal phosphonates and diversity of ligand conformation

In this work, the structure diversity of three-component molecular metal phosphonates has been achieved by varying reaction temperature. Two dinuclear Co(II) phosphonate complexes, [Co2(H4tpmb)(phen)2(H2O)6]·2H2O (1·2H2O) and [Co2(H6tpmb)2(1,10-phen)2(H2O)2] (2), with M2L and M2L2 types, respectively, have been successfully synthesized from the reactions of CoCl2·6H2O, 1,2,4,5-tetrakis(phosphorylmethyl)benzene (H8tpmb), and 1,10-phenanthroline (phen) at room temperature and 60 °C, respectively. In comparison, only M2L Ni(II) phosphonate complex [Ni2(H4tpmb)(phen)2(H2O)6]·2H2O (3·2H2O), which is isostructural and isomorphous with Co(II) analogue 1·2H2O, has been obtained by using NiCl2·6H2O instead of CoCl2·6H2O under similar reaction conditions at both room temperature and 60 °C. The M(II) center in 1–3 all adopts a slight distorted octahedral geometry of {MO4N2}, made up of one phosphonate O atom, three coordination water molecules and one chelated phen ligand in 1 and 3, and three phosphonate O atoms, one coordination water molecule and one chelated phen ligand in 2. The H8tpmb ligand is partially deprotonated to be a tetracharged H4tpmb4– anion with a tctc (trans, cis, trans, cis) conformation in 1 and 3 and a dicharged H6tpmb2– anion with a ctct (cis, trans, cis, trans) conformation in 2. Complexes 1–3 are thermally stable upon heating to approximately 262–282 °C.

Probing the structure of Copper(II)-Casiopeina type coordination complexes [Cu(O-O)(N-N)]+ by EPR and ENDOR spectroscopy

Although copper based complexes have been widely used in homogeneous catalysis, more recently they are attracting considerable attention as pharmaceutical therapeutic agents. Of paramount importance in their efficacy of use is their structure and electronic properties, which can be thoroughly probed using advanced EPR techniques. In this study, a series of [Cu(acac)(N-N)]+ Casiopeina type complexes were investigated, bearing a series of diimine N-N ligands (including bipy, phen, Py-bipy and dppz). All complexes displayed rhombic g and CuA tensors, although the extent of rhombicity was dependent on the N-N ligand. Greater Cu(II)-N2 in-plane distortion, away from the square planar arrangement, was detected by CW W-band EPR for the smaller bipy and phen ligands compared to the larger Py-bipy and dppz ligands. Changes in ligand spin density distributions (over the 1H and 14N nuclei) were revealed by CW Q-band ENDOR. The largest components of the 1H imine and 14N hyperfine coupling decreased as the ligand size increased, following the trend bipy > phen > Py-bipy > dppz. These results indicate how even small structural and electronic (spin density) perturbations within the Casiopeina family of Cu(II) complexes can be probed by advanced EPR methods.

Syntheses and luminescent properties of a series of new lanthanide azelates

A series of new lanthanide azelates [Ln(aze)(Haze)(H2O)]·H2O {Ln = La (1a), Ce (1b), Pr (1c); H2aze = azelaic acid}, [Ln2(aze)3(phen)2]·H2O [Ln = Nd (2a), Er (2b); phen = 1,10-phenanthroline], [Sm(aze)(Haze)(phen)]·2H2O (3), [Gd(aze)(phen)2]·ClO4 (4) and (Hphen)[Tb2(aze)2(phen)4]·3ClO4 (5) were hydrothermally prepared and structurally characterized.1a-c are isostructural and show 3-D framework based on 1-D infinite [Ln-O-Ln]n chain. 2a-b exhibit sql layer, while 3 displays 1-D chain, where phen ligands locate at both sides of the chain. The Ln3+ ions of 4 and 5 are connected by aze2− into two different types of rare cationic 1-D chains. The luminescent investigations show that both 2a and 2b exhibit interesting NIR luminescence and 5 displays a good potentiality as a luminescent sensor targeted for Fe3+ ion. Of particular interest, lanthanide azelates have not been to date documented, while this work presents the only examples of lanthanide azelates exhibiting luminescent properties. The magnetic properties of some lanthanide azelates were also investigated.

Insights into the interactions between DNA and an infinite clamp-like copper (II) complex

A Cu(II) complex [Cu2(phen)2(NAB)2(HO)]n (phen = 1, 10-phenanthroline and NABH = p-N, N-(2-hydroxyethyl)amino benzoic acid) was synthesized, and its structure was confirmed by X-ray diffraction. The structure of the complex appeared to be clamp-like, in which Cu(II) atoms adopt distorted square pyramidal geometry. Each Cu(II) is coordinated by two nitrogen atoms in phen ligand and two carboxyl oxygen atoms from each of the two NABH ligands. The clamp-like coordination units are bridged by adjacent hydroxyethyl groups into infinite 1D chain, which are further linked by extensive O···H hydrogen bonds and π–π interactions to form 3D networks. The titled complex displayed weak double-stranded DNA interaction activity. Spectroscopic and theoretical simulation results indicated that the complex attached onto DNA surface through hydrogen bonding with base pairs. A novel benzoic acid derivative with two extremity hydroxyethyl groups was designed and used as auxiliary ligand to synthesize mixed coordinating clamp-like Cu(II)-phenanthroline complex. Hydrogen bonding played crucial role in bridging the clamps into infinite 1D chain and also the DNA complex interaction mode.

Synthesis, Characterization, and Antibacterial Activity of Complexes of Hg(II) with Mixtures of 3-Hydrazonoindolin-2-one and Diphosphine, or Diimine Ligands

In the current study, six new tetrahedral Hg(II) complexes of 3-hydrazonoindolin-2-one (HZI) with diphosphines (dppm, dppe, dppp, dppb) or diimines (bipy, phen) ligands have been prepared and characterized by molar conductivity, IR, 1H, 13C, and 31P NMR spectra. Antibacterial activity of these complexes has been tested against three bacterial species: Staphylococcusepidermidis and Staphylococcusaureus (gram positive) and Citrobacerfreundii (gram negative). All complexes are more active against Staphylococcusaureus than amikacin, while [Hg2(HZI)2(dppm)2]Cl4 (1), [Hg(HZI)(dppe)]Cl2 (2), and [Hg(HZI)(Phen)]Cl2 (6) complexes are more active against Staphylococcusepidermidis than amikacin. The complexes 2, [Hg(HZI)(dppp)]Cl2 (3), and 6 are active against Citrobacterfreundii.

Synthesis and crystal structure of (1,10-phenanthroline-κ2 N,N')[2-(1H-pyrazol-1-yl)phenyl-κ2 N 2,C 1]iridium(III) hexa-fluorido-phosphate with an unknown number of solvent mol-ecules.

The cationic complex in the title compound, [Ir(C9H7N2)2(C12H8N2)]PF6, comprises two phenyl-pyrazole (ppz) cyclo-metallating ligands and one 1,10-phenanthroline (phen) ancillary ligand. The asymmetric unit consists of one [Ir(ppz)2(phen)]+ cation and one [PF6]- counter-ion. The central IrIII ion is six-coordinated by two N atoms and two C atoms from the two ppz ligands as well as by two N atoms from the phen ligand within a distorted octa-hedral C2N4 coordination set. In the crystal structure, the [Ir(ppz)2(phen)]+ cations and PF6 - counter-ions are connected with each other through weak inter-molecular C-H⋯F hydrogen bonds. Additional C-H⋯π inter-actions between the rings of neighbouring cations consolidate the three-dimensional network. Electron density associated with additional disordered solvent mol-ecules inside cavities of the structure was removed with the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The given chemical formula and other crystal data do not take into account the unknown solvent mol-ecule(s). The title compound has a different space-group symmetry (C2/c) from its solvatomorph (P21/c) comprising 1.5CH2Cl2 solvent mol-ecules per ion pair.

A chiral binuclear nickel(II) complex with Schiff base ligand: synthesis, crystal structure, DNA/BSA binding interactions and SOD activity

A chiral binuclear Ni(II) complex [Ni2(o-van-ala)2(phen)2] (o-van-ala = a Schiff base derived from o-vanillin and l-alanine, phen = 1,10-phenanthroline) has been synthesized and characterized by physicochemical and spectroscopic methods. Single-crystal X-ray diffraction result showed that the Ni(II) complex contains two nickel centers, which are further bridged and coordinated by two o-van-ala Schiff base and two phen ligands in a cis-conformation. Each nickel atom is six-coordinated in a distorted NiN3O3 octahedral geometry. The interaction of the Ni(II) complex with calf thymus DNA (CT-DNA) has been investigated by spectroscopic methods. Based on results obtained, an intercalative binding mode has been proposed. In addition, the interaction between the Ni(II) complex and bovine serum albumin (BSA) has also been studied by various spectroscopic techniques. Results indicated that the Ni(II) complex can quench the intrinsic fluorescence of BSA in a static quenching process. The binding constant (Kb) and the number of binding sites (n) were calculated to be 2.92 × 106 M−1 and 1.21, respectively. Site-selective competitive binding experiment indicated that the binding site of the Ni(II) complex locates in site I in sub-domains IIA of BSA. The Ni(II) complex also displayed a significant superoxide anion scavenging activity.

Fluorescent SiO2@Tb3+(PET-TEG)3Phen Hybrids as Nucleating Additive for Enhancement of Crystallinity of PET.

A hybrid polymer of SiO2@Tb3+(poly(ethylene terephthalate)-tetraglycol)3 phenanthroline (SiO2@Tb3+(PET–TEG)3Phen) was synthesized by mixing of inorganic SiO2 nanoparticles with polymeric segments of PET–TEG, whereas PET–TEG was achieved through multi-step functionalization strategy. Tb3+ ions and β-diketonate ligand Phen were added in resulting material. The experimental results demonstrated that it was well blended with PET as a robust additive, and not only promoted the crystallinity, but also possessed excellent luminescence properties. An investigation of the mechanism revealed that the SiO2 nanoparticles functioned as a crystallization promotor; the Tb3+ acted as the fluorescent centre; and the PET–TEG segments played the role of linker and buffer, providing better compatibility of PET matrix with the inorganic component. This work demonstrated that hybrid polymers are appealing as multifunctional additives in the polymer processing and polymer luminescence field.

Synthesis, spectroscopic characterization (FT-IR, Raman, UV-VIS, XRD), DFT studies and DNA binding properties of [Ni(C6H5CH2COO)(C12H8N2)2](ClO4)(CH3OH) compound

A nickel (II) compound, [Ni(C6H5CH2COO)(C12H8N2)2](ClO4)(CH3OH), bearing phenyl acetic acid (paa) and 1,10′-phenanthroline (phen) ligands was synthesized and characterized using single crystal X-ray diffraction (XRD), FT-IR, Raman and UV-VIS spectroscopic methods. This compound belongs to triclinic system with space group P-1. In order to explain chemical structure and vibrational properties, theoretical calculations were performed. All theoretical computations were carried out using the DFT method at B3LYP/LanL2DZ level of theory. We obtained good agreement between the experimental and the theoretical results. Using the DFT method, HOMO-LUMO energies values were computed to get an insight into the material. Detailed information about local and global chemical activity, electrophilic and nucleophilic nature of complex were theoretically obtained. Moreover, UV-VIS spectrophotometer and fluorescence spectrophotometer were used to determine the interaction between complex and CT-DNA. Obtained results indicate that there are strong chemical interaction between CT-DNA and complex. Complex shows electrostatic or groove mode binding with CT-DNA. This complex can destroy the DNA acting on cancer cells. In order to develop anti-cancer drugs, It is hoped that this study may help theoretically and experimentally to produce anticancer drugs.

Effect of Ligand Structure on the Electron Density and Activity of Iridium Catalysts for the Borylation of Alkanes.

An in-depth study of iridium catalysts for the borylation of alkyl C-H bonds is reported. Although the borylation of aryl C-H bonds can be catalyzed by iridium complexes containing phen or bpy ligands at mild temperatures and with limiting arene, the borylation of alkyl C-H bonds remains underdeveloped. We prepared a library of phenanthrolines that contain varying substitution patterns. The corresponding phen-Ir trisboryl carbon monoxide complexes were synthesized to determine the electron-donating ability of these ligands, and the initial rates for the borylation of the C-H bonds in THF and diethoxyethane β to oxygen catalyzed by Ir complexes containing these ligands were measured. For some subsets of these ligands, the donor ability correlated positively with the rate of C-H borylation catalyzed by the complexes containing ligands within a given subset. However, across subsets, ligands possessing similar donor properties to one another form catalysts for the borylation of alkyl C-H bonds with widely varying activity. This phenomenon was investigated computationally, and it was discovered that the stabilizing interactions between the phenanthroline ligand and the boryl ligands attached to Ir in the transition state for C-H oxidative addition could account for the differences in the activity of the catalysts that possess similar electron densities at Ir. The effect of these interactions on the borylation of secondary alkyl C-H bonds is larger than it is on the borylation of primary alkyl C-H bonds.

Exploring the structure of a ruthenium acetate cluster for biological purposes

This work evaluates the cytotoxicity of [Ru3(μ3-O)(μ-OAc)5{μ-η1(C),η2(N,N)-phen}(py)2](PF6) (1), a triruthenium acetate cluster combined with an ortho-metallated 1,10-phenanthroline (phen) ligand, along with its interactions with biomolecules. In vitro cytotoxicity tests against the B16F10 (murine melanoma) and L929 (fibroblast) cell lines showed that 1 decreased cancer cell viability by 50% at 25 μM, while it requires 50 μM of free phen ligand to achieve the same effect. Importantly, 1 is not active against non-tumor cell model L929 up to 100 μM. Spectrophotometric titrations suggest that 1 and DNA interacted weakly through electrostatic attraction and semi-intercalation. Despite the presence of a planar and aromatic ligand, relative viscosity measurements are not consistent with the DNA intercalation of 1, presumably due to the small size of phenanthroline. The protein-binding ability of compound 1 was evaluated using human serum albumin (HSA) as a model and monitored by spectroscopic techniques, including steady-state emission and absorption, time-resolved luminescence, and circular dichroism, CD. Compound 1 quenches the HSA emission efficiently (Kap = 4.72 × 108 M−1, 298 K) mostly by static quenching, consistent with its relatively strong binding to HSA (Kb = 3.70 × 106 M−1, 298 K). Analysis of ΔH and ΔS values (604 kJ/mol and 2162 J/mol K, respectively) suggest the contribution of hydrophobic interactions. CD measurements demonstrated that the protein α-helical structure decreased in the presence of l, indicating a partial conformation change of HSA. Although the interaction of 1 with DNA is weak, its binding to the model protein HSA is strong, such that the cytotoxicity of the complex may be attributed to protein-complex interactions. This work provides a framework to design new triruthenium acetates to achieve stronger and more selective binding to biomolecules. Importantly, the selective activity of 1 towards a cancer cell line, while remaining inactive against healthy cells, represents a critical finding for the design of new cancer therapeutics based on triruthenium acetate clusters.

SelectiveN-formylation/N-methylation of amines andN-formylation of amides and carbamates with carbon dioxide and hydrosilanes: promotion of the basic counter anions of the zinc catalyst

A Zn(OAc)2catalyst bearing the 1,10-phenanthroline (phen) ligand was efficient in theN-formylation of organic amine derivatives (e.g., amines, amides, and carbamates) using carbon dioxide (CO2) and hydrosilanes.