Mesomorphism and luminescence properties of platinum(II) complexes with tris(alkoxy)phenyl-functionalized pyridyl pyrazolate chelates

A series of new mesomorphic platinum(II) complexes 1 – 4 bearing pyridyl pyrazolate chelates are reported herein. In this approach, pyridyl azolate ligands have been strategically functionalized with tris(alkoxy)phenyl groups with various alkyl chain lengths. As a result, they are ascribed to a class of luminescent metallomesogens that possess distinctive morphological properties, such as their intermolecular packing arrangement and their associated photophysical behavior. In CH₂Cl₂, independent of the applied concentration in the range 10^?6–10^?3 M , all Pt^II complexes exhibit bright phosphorescence centered at around 520 nm, which is characteristic for monomeric Pt^II complexes. In stark contrast, the single‐crystal X‐ray structure determination of [Pt(C4pz)₂] ( 1 ) shows the formation of a dimeric aggregate with a notable Pt???Pt contact of 3.258 Å. Upon heating, all Pt^II complexes 1 – 4 melted to form columnar suprastructures, for which similar intracolumnar Pt???Pt distances of approx. 3.4–3.5 Å are observed within an exceptionally wide temperature range (>250 °C), according to the powder XRD data. Upon casting into a neat thin film at RT, the luminescence of 1 – 4 is dominated by a red emission that spans 630–660 nm, which originates from the one‐dimensional, chainlike structure with Pt–Pt interaction in the ground state. Taking complex 4 as a representative, the emission intensity and wavelength were significantly decreased and blueshifted, respectively, on heating from RT to 250 °C. Further heating to liquefy the sample alters the red emission back to the green phosphorescence of the monomer. The results highlight the pivotal role of tris(alkoxy)phenyl groups in the structural versus luminescence behavior of these Pt^II complexes.     

X‐ray structures,spectroscopic, electrochemical,thermal, antibacterial,and DFT studies of two nickel(II) and cobalt(III) complexes constructed from a new quinazoline‐type ligand

Two two‐dimensional supramolecular Nickel(II) and Cobalt(III) complexes, [Ni( L ² )₂]·2CH₃OH ( 1 ) and [2Co( L ² )₂] ( 2 ) ( HL ²  = 1‐(2‐{[(E)‐3‐bromo‐5‐chloro‐2‐hydroxybenzylidene]amino}phenyl)ethanone oxime), were synthesized via complexation of salts acetate with HL ¹ (2‐(3‐bromo‐5‐chloro‐2‐hydroxyphenyl)‐4‐methyl‐1,2‐dihydroquinazoline 3‐oxide, H is the deprotonatable hydrogen). During the reaction, the C–N bond in HL ¹ is converted into the C=N–OH group in HL ² . The spectroscopic data of both complexes were compared with the ligand HL ¹ . HL ¹ and both complexes were determined by single‐crystal X‐ray crystallography. The differently geometric features of the obtained complexes 1 and 2 are observed. In the crystal structure, 1 and 2 form an infinite 1‐D chain‐like and 2‐D supramolecular frameworks. EPR spectroscopy of 2 was investigated. Moreover, electrochemical properties and antimicrobial activities of both complexes were also studied. In addition, the calculated HOMO and LUMO energies show the character of HL ¹ , complexes 1 and 2 . The electronic transitions and spectral features of HL ¹ and both complexes were discussed by TD‐DFT calculations.     

Computational studies on the injection,transport, absorption,and phosphoresce properties of a series of cationic iridium (III) complexes [Ir(C∧N)2(L)2]+ (C∧N = ppy,tpy, dfppy,bzq)

Quantum chemistry methods are applied to investigate the electronic structures, injection and transport properties, absorption and phosphorescence mechanism of a series of Iridium (III) complexes [Ir(C∧N)₂(L)₂]⁺ (L = 4‐pyCO₂Et; C∧N = 2‐phenylpyridine, 1 ; 2‐(4‐tolyl)pyridine, 2 ; 2‐(4,6‐difluorophenyl)pyridimato, 3 ; benzoquinoline, 4 ), which may be used as emitters on organic light emitting diodes (OLEDs). Calculations of ionization potentials and electron affinities are used to evaluate the injection abilities of holes and electrons into these complexes. The reorganization energy (λ) calculations show that the four complexes are suitable as emitters in OLEDs. The absorptions and emissions can be tuned by adding substituent to the ppy ligand or extending the π‐conjugation effect of the C∧N ligand, and quantum yields of 1 – 4 are investigated. In addition, no solvent effect is observed in the absorption and emission spectra. © 2012 Wiley Periodicals, Inc.     

Palladium(II) and platinum(II) complexes of (1R,2R)‐(−)‐1,2‐diaminocyclohexane (DACH) with various carboxylato ligands and their cytotoxicity evaluation

Several palladium(II) and platinum(II) complexes analogous to oxaliplatin, bearing the enantiomerically pure (1R,2R)‐(?)‐1,2‐diaminocyclohexane (DACH) ligand, of the general formula {MX₂[(1R,2R)‐DACH]}, where M = Pd or Pt, X (COO)₂, CH₂(COO)₂, , , {1,1′‐C₅H₈(CH₂COO)₂}, [1,1′‐C₆H₁₀(CH₂COO)₂], [1,1′‐(COO)₂ferrocene], , , , MeCOO and Me₃CCOO, were synthesized. All the complexes prepared were characterized physicochemically and spectroscopically. Some selected complexes were screened in vitro against several tumor cell lines and the results were compared with reference standard drug, oxaliplatin. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis,spectroscopic properties,density functional theory calculations and nonlinear optical properties of novel complexes of 5‐hydroxy‐4,7‐dimethyl‐6‐(phenylazo)coumarin with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions

5‐Hydroxy‐4,7‐dimethyl‐6‐(phenylazo)coumarin (L) has been synthesized and its novel complexes with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions have also been prepared and identified using various analytical tools. The complexes are octahedral binding via one/two oxygen, nitrogen atoms for 1:1 and 1:2 complexes and two/three coordinated water molecules. All the prepared solid complexes behave as neutral in dimethylformamide. The optimized structures of the studied complexes were theoretically investigated at the B3LYP/6‐311G** level. Molecular stability and bond strengths were investigated by applying natural bond orbital analysis. The geometries of the studied complexes are non‐planar as indicated from the values of dihedral angles. The global properties of hardness, global softness and electronegativity were computed. The calculated small energy gap between highest occupied and lowest unoccupied molecular orbital energies shows that charge transfer occurs within the complexes. The obtained total static dipole moment, mean polarizability, anisotropy of polarizability and mean first‐order hyperpolarizability (<β>) were compared with those of urea as a reference material. The results for <β> showed that the complexes are excellent candidates as nonlinear optical materials. The three‐dimensional plots of the molecular electrostatic potential for some selected complexes were investigated.     

反式-双(二甲基苯膦)铂配合物二阶非线性光学性质的密度泛函理论研究

采用密度泛函理论B3LYP方法,在6-31G(d)的水平上对两种反式-双(二甲基苯膦)铂配合物的几何构型进行优化,在获得稳定构型基础上,利用TD-B3LYP方法得到体系的UV-Vis吸收光谱,并用有限场(FF/B3LYP)方法探讨体系的二阶非线性光学性质(NLO).结果表明,此类铂配合物具有较大的二阶极化率,以及在可见光范围内透明等优点,是具有很好应用前景的非线性光学材料.     

Electronic structures and optical properties of neutral substituted fluorene-based cyclometalated platinum(II)-acetylide complexes: A DFT exploration

We report a combinational DFT and TD-DFT study of the electronic and optical properties of several tridentate cyclometalated mononuclear [Pt(C^N^N)(CCR)] (1-3), [Pt(C^N^N)(CCRCCH)] (4), and dinuclear [Pt(C^N^N)(CCRCC)Pt(C^N^N)] (5 (C₂ symmetry) and 5′ (C_s symmetry)) platinum(II) complexes with σ-acetylide ligand bearing fluorene substituents, where HC^N^N = 6-aryl-2,2′-bipyridine, R = fluorene-2,7-diyl 1, 4, 5 and 5′, R = 9,9-dimethylfluorene-2,7-diyl 2, R = 9,9-diethylfluorene-2,7-diyl 3. The structural and electronic properties of the ground- and lowest triplet state and the EA and IP values of the complexes are discussed. It is found that all of the lowest-lying absorptions are categorized as the LLCT combined with the MLCT transitions. The oscillator strengths of the lowest energy absorptions get a remarkable enhancement for the dinuclear complexes 5 and 5′compared to 1-4 due to the increase of electronic delocalization on the more planar molecular geometry. In general, the phosphorescent emissions of these complexes in CH₂Cl₂ are the reverse process of their lowest energy absorption transitions, except that of 4 is assigned as ³[π∗−π]/³MLCT transition because of the strengthened electronic localization effect and the interaction with the solvent in the lowest triplet state. In addition, these complexes hold promise as a new kind of nonlinear optical material owing to their large static first hyperpolarizabilities (β₀). The β₀ value has increased in the dinuclear complexes in contrast to those of the mononuclear ones owing to their larger transition moment and smaller transition energy.     

Exploring the electro‐optical properties of conjugated polymers based on oligo‐selenophene and oligo(3,4‐ethylenedioxyselenophene)

For seeking high‐efficiency narrow‐band‐gap donor materials to enhance short‐circuit current density for organic solar cells, a series of oligo‐selenophene (OS) and oligo(3,4‐ethylenedioxyselenophene) (OEDOS) with various chain lengths were designed and characterized using density functional theory (DFT) and time‐dependent DFT calculations. Based on the results, it can be seen that with increasing chain length of the oligomers in both syn‐ and anti‐adding manners, the bond length alternation is decreased which indicates that the π‐electron delocalization is increased. Also, when the chain length is increased the electronic energy gap and the optical energy gap are decreased. It can be concluded that the syn‐(OS)_n=10,14,15, anti‐(OS)_n=14 and anti‐(OEDOS)_n=7–12 oligomers can act as low‐band‐gap polymers. Therefore they can absorb more sunlight based on maximum wavelength (higher than 620 nm). Furthermore, a red shift in the simulated absorption spectra of (OS)_n and (OEDOS)_n donors is observed. It is found that (OS)_n=14,15 with syn configuration of the extended oligomers is the most suitable donor for the design of high‐performance organic solar cells possessing a narrow electronic band gap, high exciton lifetime and broad and intense absorption spectra that cover the solar spectrum leading to complete light‐harvesting efficiency.     

Synthesis,characterization, electronic structure,and non‐linear optical properties (NLO) of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 5‐phenylazo‐8‐hydroxyquinoline using DFT approach

5‐phenylazo‐8‐hydroxyquinoline and its newly metal complexes with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions have been prepared and characterized using different analytical techniques. The complexes are distorted octahedral binding via one oxygen and nitrogen atoms of the ligand; two/three coordinated water molecules. 1:1 complexes contain one chloride or OH⁻ ion and some complexes have one or two water of hydration whereas 1:2 complexes contain only two coordinated water molecules in their coordination spheres. All complexes behave as neutral in dimethylformamide (DMF). The electronic structure and non‐linear optical parameters NLO of the complexes (ML and ML2) are investigated theoretically at the B3LYP/GEN level of theory. The geometries of the studied complexes are non‐planner. The calculated E_HOMO and E_LUMO energies of the studied complexes were used to calculate the global properties; hardness (η), global softness (S) and electronegativity (χ). The total dipole moment (μ_tot), static total and anisotropy of polarizability (α, Δα) and static first hyperpolarizability (β) values were calculated and compared with urea as a reference compound. The studied complexes show promising optical properties.     

Synthesis,crystal structure,and spectroscopic and thermal properties of the polymeric compound catena‐poly[[bis(2,4‐dichlorobenzoato)zinc(II)]‐μ‐isonicotinamide]

Zinc(II) carboxylates with O‐, S‐ and N‐donor ligands are interesting for their structural features, as well as for their antibacterial and antifungal activities. The one‐dimensional zinc(II) coordination complex catena‐poly[[bis(2,4‐dichlorobenzoato‐κO)zinc(II)]‐μ‐isonicotinamide‐κ²N¹:O], [Zn(C₇H₃Cl₂O₂)₂(C₆H₆N₂O)]_n, has been prepared and characterized by IR spectroscopy, single‐crystal X‐ray analysis and thermal analysis. The tetrahedral ZnO₃N coordination about the Zn^II cation is built up by the N atom of the pyridine ring, an O atom of the carbonyl group of the isonicotinamide ligand and two O atoms of two dichlorobenzoate ligands. Isonicotinamide serves as a bridge between tetrahedra, with a Zn...Zn distance of 8.8161 (7) Å. Additionally, π–π interactions between the planar benzene rings contribute to the stabilization of the extended structure. The structure is also stabilized by intermolecular hydrogen bonds between the amino and carboxylate groups of the ligands, forming a two‐dimensional network. During thermal decomposition of the complex, isonicotinamide, dichlorobenzene and carbon dioxide were evolved. The final solid product of the thermal decomposition heated up to 1173 K was metallic zinc.     

Synthesis and Crystal Structures of Bis(1‐{(E)‐2‐pyridinylmethylidene}‐semicarbazone)iron(II) and ‐copper(II) Diperchlorate Monohydrates

The pyridine‐2‐carbaldehyde semicarbazone ligand (HL) reacts with iron(II) and copper(II) perchlorates in boiling ethanol to yield red‐violet [Fe^II(HL)₂](ClO₄)₂·H₂O ( 1 ) and light‐green crystals [Cu^II(HL)₂](ClO₄)₂·H₂O ( 2 ). The crystals are triclinic with the metal ions in an octahedral environment, coordinated to two nitrogen and one oxygen‐donor atom from HL. Electronic, magnetic and electrochemical properties are presented as well.     

A luminescent bis(pyridyl)‐substituted benzimidazole platinum(II) complex exhibiting an intermolecular anagostic interaction

The photophysical properties of transition metal complexes of the 5,6‐dimethyl‐2‐(pyridin‐2‐yl)‐1‐(pyridin‐2‐ylmethyl)‐1H‐benzimidazole ligand are of interest. Dichlorido[5,6‐dimethyl‐2‐(pyridin‐2‐yl)‐1‐(pyridin‐2‐ylmethyl)‐1H‐benzimidazole‐κ²N ²,N ³]platinum(II), [PtCl₂(C₂₀H₁₈N₄)], is luminescent in the solid state at room temperature. The compound displays a distorted square‐planar coordination geometry. The Pt—N(imidazole) bond length is shorter than the Pt—N(pyridine) bond length. The extended structure reveals that symmetry‐related molecules display weak C—H…N, C—H…Cl, and C—H…Pt hydrogen‐bonding interactions that are clearly discernable in the Hirshfeld surface and fingerprint plots. The intermolecular C—H…Pt and C—H…N interactions have been explored using density functional theory. The result of an analysis of the distance dependence of C—H…Pt yields a value consistent with that observed in the solid‐state structure. The energy of interaction for the C—H…Pt interaction is found to be about −11 kJ mol⁻¹.     

Pt(II) complexes immobilized on polymer‐modified magnetic carbon nanotubes as a new platinum drug delivery system

We combine nanotechnology and chemical synthesis to create a novel multifunctional platinum drug delivery vehicle based on magnetic carbon nanotubes (multiwall carbon nanotubes/Fe₃O₄@poly(citric acid)/cis‐[(Pt(1,7‐phenanthroline)(DMSO)Cl₂)]‐b‐poly(ethylene glycol) (MCNTs/FO@PC/Pt(II)‐b‐PEG)) for targeted cancer therapy. MCNTs/FO@PC/Pt(II)‐b‐PEG was conveniently prepared by conjugating cis‐[Pt(1,7‐phenanthroline)(DMSO)Cl₂] complex to MCNTs/FO@PC‐b‐PEG via strong hydrogen‐bonding interactions. In comparison with free cisplatin and Pt(II) complex, MCNTs/FO@PC/Pt(II)‐b‐PEG shows higher solubility in aqueous solution and higher cytotoxicity towards human cervical cancer HeLa cells and human breast cancer MDA‐MB‐231 cells. In vitro release experiments revealed that the platinum drug‐loaded delivery system is relatively stable under physiological conditions (pH = 7.4 and 37 °C) but susceptible to acidic environments (pH = 5.6 and 37 °C) which would trigger the release of loaded drugs. Fluorescence microscopy studies revealed that this magnetic nanohybrid system possesses marked cell‐specific targeting in vitro in the presence of an external magnetic field. The results indicated that the prepared superparamagnetic MCNTs/FO@PC/Pt(II)‐b‐PEG nanohybrid system is a promising candidate for inhibiting the proliferation of cancer cells.     

Synthesis,crystal structure and spectroscopic properties of trans‐dibromidobis(2,2‐dimethylpropane‐1,3‐diamine‐κ2N,N′)chromium(III) perchlorate

The title complex salt, trans‐anti‐[CrBr₂(Me₂tn)₂]ClO₄ (where Me₂tn = 2,2‐dimethylpropane‐1,3‐diamine, C₅H₁₄N₂), was prepared and its structure determined by single‐crystal X‐ray diffraction at 100 K. The asymmetric unit contains three conformationally similar complex cations and three perchlorate anions. In each complex cation, the Cr^III centre is coordinated by four N atoms of two chelating Me₂tn ligands in the equatorial plane and by two Br atoms in a trans‐axial arrangement, to give a distorted octahedral geometry. Interionic contacts are dominated by extensive hydrogen bonding, involving the NH groups of the Me₂tn ligand as donors and the anion O atoms or coordinated Br atoms as acceptors, resulting in two‐dimensional layers in the bc plane. Ligand field analysis based on the angular overlap model, and IR and electronic spectroscopic properties, are also discussed.     

Synthesis,spectroscopic characterization,biological screening and in vitro cytotoxic studies of 4‐methyl‐3‐thiosemicarbazone derived Schiff bases and their Co (II), Ni (II), Cu (II) and Zn (II) complexes

A series of twenty compounds inclusive of bidentate Schiff bases derived from condensation of 4‐methyl‐3‐thiosemicarbazide with substituted derivatives of napthaldehyde/benzaldehyde/salicylaldehyde and their mononuclear Co (II), Ni (II), Cu (II) and Zn (II) complexes in molar ratio (1:1) were synthesized and characterized. The coordination behavior, modes of bonding and overall geometry of the compounds was known from the elemental analysis, spectral techniques (IR, UV–Vis, ¹H NMR, ¹³C NMR, ESR and ESI‐mass), magnetic moment measurements, molar conductance, thermal and powder XRD studies. The studies revealed octahedral geometry for all the complexes where ligands coordinated in a neutral bidentate manner (NS) via nitrogen atom of azomethine group and sulphur atom of thione group with the metal centre. In vitro biological effects of the compounds were tested against four bacterial species and two fungal strains. The results indicated that the metal complexes showed a marked enhancement in biocidal activity in comparable with the parent Schiff bases. In vitro anticancer activity against the malignant tumor cell lines; human alveolar adenocarcinoma epithelial cell line (A549), human breast adenocarcinoma cell line (MCF7), human prostate cancer cell line (DU145) and human normal lung cell line (MRC‐5) using MTT assay, exposed compound 16 as a leading member with lowest IC₅₀ value of 10.6 ± 0.14 μM against (A549) cell line.     

Synthesis,spectroscopic, thermal and biological aspects of drug‐based copper(II) complexes

A series of novel complexes of the type Cu(II)(L_n)₂(H₂O)₂]^•xH₂O [where L_n = L _1–4 , these ligands being described as: L ₁ , 2‐({4‐[6,7‐dihydrothieno[3,2‐c]pyridin‐5(4H)‐ylsulfonyl]phenylimino}methyl)phenol, x = 1; L ₂ , 2‐({4‐[6,7‐dihydrothieno[3,2‐c] pyridin‐5(4H)‐ylsulfonyl]phenylimino}methyl)‐5‐(methoxy)phenol, x = 2; L ₃ , 5‐chloro‐2‐({4‐[6,7‐dihydrothieno[3,2‐c]pyridin‐5(4H)‐ylsulfonyl]phenylimino}methyl)phenol, x = 2; and L ₄ , 5‐bromo‐4‐chloro‐2‐({4‐[6,7‐dihydrothieno[3,2‐c]pyridin‐5(4H)‐ylsulfonyl]phenylimino} methyl)phenol, x = 1] was investigated. They were characterized by elemental analysis, IR, ¹H‐NMR, ¹³C‐NMR and electronic spectra, magnetic measurements and thermal studies. The FAB‐mass spectrum of [Cu(II)( L ₁ )₂(H₂O)₂]^•H₂O was determined. A magnetic moment and reflectance spectral study revealed that an octahedral geometry could be assigned to all the prepared complexes. Ligands (L_n) and their metal complexes were screened for their in vitro antibacterial activity against Bacillus subtillis, Pseudomonas aeruginosa, Escherichia coli and Serratia marcescens bacterial strains. Kinetic parameters such as order of reaction (n), the energy of activation (E_a), the pre‐exponential factor (A), the activation entropy (ΔS^≠), the activation enthalpy (ΔH^≠) and the free energy of activation (ΔG^≠) are reported. Copyright © 2011 John Wiley & Sons, Ltd.     

Experimental studies on the trans-influence of boryl ligands in square-planar platinum(II) complexes

A series of platinum(II) boryl complexes of general formula trans-[(Cy(3)P)2Pt(Br)(BX2)], including the rare dibromoboryl species trans-[(Cy(3)P)2Pt(Br)(BBr2)], were synthesized by oxidative addition of the B-Br bond of a number of bromoboranes to [Pt(PCy3)2]. X-ray diffraction studies were performed on several such compounds. Comparison of the Pt--Br bond lengths allowed an empirical assessment of the trans-influence of different boryl ligands. A trans-influence scale was thus deduced and the results were compared with those previously computed for compounds of the type trans-[(Me(3)P)2Pt(Cl)(BX2)].     

1,2-polybutadiene complexes with d8 pseudo-square-planar transition-metal salts based on nickel(II), palladium(II), and platinum(II)

The effects of four d⁸ transition-metal complexes from Group 10 on the thermal, mechanical, optical, and spectroscopic properties of atactic 1,2-polybutadiene are compared, in addition to their ability to induce gelation. Olefin coordination and subsequent metal-catalyzed chemical crosslinking occur much more quickly, and to a greater extent, at ambient temperature with PdCl₂(CH₃CN)₂ than with PtCl₂(C₆H₅CN)₂. Alkene side groups in the polymer attack the pseudo-square-planar metal center (i.e., Pd²⁺ or Pt²⁺) from above or below the plane of the coordinatively unsaturated low-molecular-weight organometallic complex and displace neutral acetonitrile or benzonitrile ligands via an associative mechanism. Gelation occurs much more quickly with Pd²⁺ than with Pt²⁺, and the ambient-temperature elastic modulus of solid polybutadiene/palladium complexes increases significantly, without high-temperature annealing, so that a weak rubbery polymer is transformed into a glass via 3 mol % Pd²⁺. Alkene functional groups in the side chain of the polymer do not coordinate to bis(dimethyl)glyoximatonickel(II) at ambient temperature because (1) it is difficult to displace anionic dimethylgloxime ligands that are bidentate; (2) these planar nickel complexes with C_2h symmetry are stacked along the c axis via interlocking methyl groups on adjacent molecules; and (3) there is a lack of π back-bonding between d_xy on Ni(II) and empty π* antibonding orbitals of CC, which typically stabilizes olefin complexes with pseudo-square-planar d⁸ metal centers. Pseudo-octahedral nickel(II) chloride hexahydrate does not form a complex with the polymer, in agreement with some macroscopic properties of these materials. The observed trend in the transition-metal-modified properties of atactic 1,2-polybutadiene in the solid state and in the gel state is Pd(II) > Pt(II) ≫ Ni(II). © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2270–2285, 2004     

Novel complexes of tris(aminomethyl)phosphanes with platinum(II): Structural, spectroscopic, DFT and biological activity studies

Two new platinum(II) complexes with tris(aminomethyl)phosphanes: [trans-PtCl₂{P(CH₂N(CH₂CH₂)₂NCH₃)₃}₂] (1Pt) and [trans-PtCl₂{P(CH₂N(CH₂CH₂)₂O)₃}₂] (2Pt) were prepared and characterized with NMR and UV-Vis spectroscopies. Their structures were investigated by X-ray crystallography and DFT methods. TDDFT calculations were employed to interpret the electronic spectra of the complexes. Obtained results are not unequivocal, however population analysis indicate, that the character of HOMO and HOMO−1 orbitals depend strongly on the electron donoring properties of the phosphane ligand. Biological activity of 2Pt complex, which is more stable and more soluble in polar solvents than 1Pt, was examined in vitro on the Vero cell line (IC₅₀ = 12.5 μM). At higher concentrations it induces apoptosis, probably due to changes of the cell cytoskeleton. Luminescence quenching studies and CD spectroscopy of interactions of 2Pt with HSA and BSA indicate that these albumins bind the complex slightly - without altering their tertiary structures, however HSA interacts with 2Pt noticeably stronger than BSA. It was also found that 2Pt does not cleave supercoiled pUC18 plasmid.