Synthesis and structural characterizations of three carbonyl(α-diimine)hydrido(triphenylphosphine)ruthenium(II) complexes with derivatives of 1,10-phenanthroline.

Three new ruthenium(II) polypyridyl complexes containing α-diimine ligands, namely, carbonylhydrido(1,10-phenanthroline-κ2N,N)bis(triphenylphosphine-κP)ruthenium(II) hexafluorophosphate, [RuH(C12H8N2)(C18H15P)2(CO)]PF6, carbonylhydrido(2,9-dimethyl-1,10-phenanthroline-κ2N,N)bis(triphenylphosphine-κP)ruthenium(II) hexafluorophosphate, and carbonylhydrido(4,7-dimethyl-1,10-phenanthroline-κ2N,N)bis(triphenylphosphine-κP)ruthenium(II) hexafluorophosphate, both [RuH(C14H12N2)(C18H15P)2(CO)]PF6, were synthesized and characterized by spectroscopic and X-ray diffraction methods. In these complexes, the ruthenium(II) ion adopts a distorted octahedral geometry. There are no intermolecular hydrogen bonds in the crystal structures of the analysed complexes and Hirshfeld surface analysis showed that the H...H contacts constitute a high percentage, close to 50%, of the intermolecular interactions.

Luminescence properties of [Ir(C

Luminescence properties of two series of [Ir(C^N)2(N^N)]+ complexes bearing deprotonated 1-phenyl-1H-pyrazole or 1-(2,4-difluorophenyl)-1H-pyrazole as cyclometalating C^N ligands and different α-diimines (2,2'-bipyridine, 1,10-phenanthroline and their derivatives) as ancillary N^N ligands have been studied in acetonitrile solutions at room temperature and in 77 K methanol/ethanol (1 : 1) matrices. Ligand and temperature induced changes in the nature of the emissive 3*[Ir(C^N)2(N^N)]+ species result in well-pronounced changes in their emission properties like emission wavelength, emission quantum yields and emission lifetimes. Depending on the nature of the coordinated C^N and N^N ligands and/or the measurement temperature, the investigated luminophores exhibit emissions arising from the intraligand transitions localized within the N^N ligand or from the metal-to-ligand charge-transfer transitions involving the Ir(C^N)2 + and N^N moieties as confirmed by means of the DFT computations. The computed DFT energies of the excited 3*[Ir(C^N)2(N^N)]+ states and outer/inner reorganization energies associated with the S0 ← 3*[Ir(C^N)2(N^N)]+ transitions remain in nice agreement with those available from the performed emission band-shape analyses. The observed agreement implies ordinary DFT computations at the B3LYP/LANL2DZ/6-31G(d,p) level of theory, even performed neglecting the spin-orbit phenomena, as enough accurate in the quantitative prediction of the most important parameters characterizing the investigated [Ir(C^N)2(N^N)]+ luminophores.

Ruthenium(II) and Iridium(III) Complexes as Tested Materials for New Anticancer Agents.

The oncological use of cisplatin is hindered by its severe side effects and a very important resistance problem. To overcome these problems, scientists have attempted to design new generation transition-metal anticancer complexes. In this study, we present new complexes, ruthenium(II) [(η6-p-cymene)RuCl(py2CO)]PF6 (1), iridium(III) [(η5-Cp)IrCl(py2CO)]PF6 (2), and NH4[IrCl4(py2CO)]·H2O (3), based on di-2-pyridylketone (py2CO). The prepared complexes were characterized by FTIR, 1H, 13C, 15N NMR, UV-Vis, PL and elemental analysis techniques. The single-crystal X-ray structure analysis and comparative data revealed pseudo-octahedral half-sandwich 1 and 2 complexes and octahedral tetrachloroiridate(III) 3 with a rare chelating κ2N,O coordination mode of py2CO. The compounds were tested in vitro against three cancer cell lines-colorectal adenoma (LoVo), myelomonocytic leukaemia (MV-4-11), breast adenocarcinoma (MCF-7), and normal fibroblasts (BALB/3T3). The most promising results were obtained for iridium(III) complex 3 against MV-4-11 (IC50 = 35.8 ± 13.9 µg/mL) without a toxic effect against normal BALB/3T3, which pointed towards its selectivity as a potential anticancer agent. Extensive research into their mode of binding with DNA confirmed for 1 and 2 complexes non-classical binding modes, while the 3D circular dichroism (CD) experiment (ΔTm) suggested that 3 induced the probable formation of covalent bonds with DNA. In addition, the obtained iridium complexes induce ROS, which, in synergy with hydrolysis promoting DNA bonding, may lead to cancer cell death.

Heteroleptic Re(CO)2 + and Re(CO)3 + complexes with α-diimines: similarities and differences in their luminescence properties.

The photophysical properties of two series of phosphorescent rhenium(i) complexes, [Re(CO)2(N^N)(tpp)2]+ and [Re(CO)3(N^N)(tpp)]+ with carbon monoxide (CO), triphenylphosphine (tpp) and α-diimine (N^N) ligands have been investigated in deoxygenated acetonitrile solution at room temperature and in solid methanol/ethanol 1 : 1 matrices at 77 K. The complexes display moderate to strong phosphorescence which is related to the N^N ligand modulated metal-to-ligand charge-transfer S0 ← 3*MLCT or intraligand S0 ← 3*LC transitions. Luminescence properties of the investigated series have been found to be very similar but some intrinsic differences between them are clearly seen. Whereas the [Re(CO)2(N^N)(tpp)2]+ series shows MLCT emission in both temperature regimes studied, the [Re(CO)3(N^N)(tpp)]+ series exhibits intrinsic changes in its emission character when the measurement temperature is lowered from 298 to 77 K. In both investigated series, their emission characteristics are strongly affected by the nature of coordinated α-diimine N^N ligands. The observed trends, changes in the radiative k r and non-radiative k nr deactivation rate constants, have been compared with those found for the previously investigated [Re(CO)3(N^N)(Cl)], [Re(CO)3(N^N)(CH3CN)]+, and [Re(CO)2(N^N)(dppv)]+ series (dppv = cis-1,2-bis(diphenylphosphino)-ethene). Similarities and differences in the spectroscopic and photophysical properties of five series of the Re(CO)3 + and Re(CO)2 + complexes have been analyzed in the view of results from DFT and TD-DFT computation and the emission band-shape analyses performed according to the Marcus-Jortner formalism.

Heteroleptic [Os(Cl)(CO)(P

A series of six [Os(Cl)(CO)(P^P)(pbi)] complexes have been synthesized and characterized using FT-IR, 1H NMR, and 31P NMR spectroscopy. Their molecular structures have been confirmed by means of X-ray diffraction studies. For each of the studied bidentate phosphines (P^P = cis-1,2-bis(diphenylphosphino)ethene - dppv, 1,2-bis(diphenylphosphino)ethane - dppe, 1,2-bis(diphenylphosphino)benzene - dppb) the applied synthesis procedure has afforded preparation of two isomers with pseudo-octahedral coordination of the osmium(ii) ion. According to X-ray data, the obtained isomers, green emissive [OC-6-24] and yellow emissive [OC-6-23] species, differ mainly in the arrangement of the 2-(2-pyridyl)benzimidazolate (pbi) anion in their structures. In the [OC-6-24] isomers the benzoimidazole fragment of the pbi ligand is located trans to the coordinated CO molecule, whereas the cis conformation is characteristic of the [OC-6-23] isomers. Each of trans-[Os(Cl)(CO)(P^P)(pbi)] shows intense green emission attributable to the excited triplet state of the pbi ligand, whereas the yellow emission from the excited cis-[Os(Cl)(CO)(P^P)(pbi)] indicates slight metal-to-ligand charge transfer character (from the Os(Cl)(CO)(P^P)+ fragment to the pbi ligand). The investigated complexes are generally well emissive with emission quantum yields up to 0.49 and emission lifetimes in the range of 10-150 µs. Only the yellow emissive cis-[Os(Cl)(CO)(dppv)(pbi)] complex exhibits remarkably different photophysical behaviour despite the fact that all three cis-[Os(Cl)(CO)(P^P)(pbi)] isomers emit in the same spectral region. In the view of DFT/TD-DFT results this has been explained by the presence of an additional excited dark state possessing distinct charge transfer character (from the Os(Cl)(CO)(pbi) fragment to the dppv ligand).

Evaluation of lymph node status in patients with urothelial carcinoma-still in search of the perfect imaging modality: a systematic review.

While accurate lymph node status evaluation in urothelial carcinoma patients is essential for the correct disease staging and, hence, establishing the most beneficial treatment strategy, the diagnostic performance of routine imaging in regards to this issue is not satisfactory. For the purpose of this article, we systematically reviewed the contemporary literature on the sensitivity and specificity of particular imaging modalities which have been studied for detecting lymph node metastases in patients diagnosed with urothelial carcinoma. The evidence reviewed shows that computed tomography (CT), although recognized as the imaging modality of choice, is associated with marked limitations, resulting in its low sensitivity for lymph node involvement detection in urothelial carcinoma patients, with no study reporting a value higher than 46% using standard cut-off values. Markedly higher sensitivity rates may be achieved with magnetic resonance imaging (MRI), especially when using ultrasmall superparamagnetic iron oxide as the contrast agent, however, no uniform protocol has been systematically studied up to date. The vast majority of recent evidence concerns positron emission tomography (PET), which is being reported to improve the diagnostic performance of CT alone, as has been demonstrated in multiple articles, which investigated the accuracy of PET/CT at primary or post-treatment staging of urothelial carcinoma patients. However, there has been substantial heterogeneity in terms of methodology and results between those studies, making it premature to draw any definitive conclusions. The results of this review lead to a conclusion, that while CT, despite being not fully satisfactory, still remains the gold-standard method of imaging for staging purposes in urothelial carcinoma, other imaging modalities are under investigation, with promising results.

Heteroleptic [Os(H)(CO)(N∧N)(tpp)2]+ and [Os(Cl)(CO)(N∧N)(tpp)2]+ complexes - comparative studies of their luminescence properties.

Two series of cationic heteroleptic osmium(ii) complexes with a coordinated CO molecule, a chloride Cl- or hydride H- anion, two monodentate triphenylphosphine (tpp) ligands and one bidentate α-dimine (N∧N) ligand were prepared from an OsCl2(CO)2(tpp)2 precursor. The investigated complexes, available in the form of PF6- salts, have been identified by means of FT-IR, 1H and 31P NMR spectroscopy and X-ray diffraction studies. Their photophysical properties have been investigated in dichloromethane solutions at room temperature and 1 : 1 ethanol-methanol matrices at 77 K. The investigated complexes exhibit metal to ligand charge-transfer (MLCT) phosphorescence with the emission characteristics distinctly affected by the nature of coordinated α-diimine N∧N and Cl- or H- ligands. Franck-Condon emission spectral band shape analyses and DFT/TD-DFT calculations have been applied to obtain more detailed insight into the nature of emissive 3*[Os(H)(CO)(N∧N)(tpp)2]+ and 3*[Os(Cl)(CO)(N∧N)(tpp)2]+ species.

The luminescence properties of heteroleptic [OsCl(CO)(N∩N)(P∩P)](+) complexes - radiative and non-radiative deactivation of the excited (3)*MLCT state.

The luminescence properties of the heteroleptic [OsCl(CO)(N∩N)(P∩P)](+) complexes with bidentate phosphine P∩P and diimine N∩N ligands have been studied in acetonitrile solutions at room temperature and in methanol/ethanol (1 : 1) glasses at 77 K. At room temperature the investigated complexes feature strong (with the quantum yields ϕem from 0.17 up to 0.64), long-lived (with lifetimes τem in the range of 1.5-44.2 µs) (3)*MLCT emission. Analysis of (3)*MLCT emission band shapes leads to the quantities relevant for the radiative electron transfer (between the Os(2+) central ion and the N∩N ligand) in the Marcus inverted region. It is also demonstrated that radiative kr and non-radiative knr decay rate constants of the excited (3)*MLCT states can be interpreted within the Mulliken-Hush formalism. Especially values of knr rate constants can be predicted using the parameters available from the analysis of the radiative (1)*MLCT ← S0 and (3)*MLCT → S0 charge transfer processes.

A Comparative Study of Stabilities and Coordination Modes of ß-Alaninephosphonic Acid in Copper(II) Heteroligand Complexes with Ethylenediamine, Diethylenetriamine or N,N,N',N',N″-Pentamethyldiethylene Triamine in Aqueous Solution.

Solution equilibrium studies on Cu(2+)-L(1)-L(2) ternary systems have been performed by pH-potentiometry, UV-Vis spectrophotometry and EPR methods {where L(1) corresponds to a polyamine such as ethylenediamine (en), diethylenetriamine (dien), N,N,N',N',N″-pentamethyldiethylenetriamine (Me(5)dien)} and L(2) denotes 2-aminoethylphosphonic acid (ß-alaninephosphonic acid)}. The results suggest the formation of heteroligand complexes with [Cu(L(1))(ß-Ala(P))] stoichiometry in all of the studied systems. Additionally, in the system with en, [Cu(en)(ß-Ala(P))H(-1)](-) is formed in basic solutions. Our spectroscopic results indicate tetragonal geometry for the [Cu(en)(ß-Ala(P))] species, a geometry slightly deviated from square pyramidal for the [Cu(dien)(ß-Ala(P))] complex, and somewhat stronger geometry distortion was present for the [Cu(Me(5)dien)(ß-Ala(P))] complex. The coordination modes in these heteroligand complexes are discussed.