Anticancer C,N-cycloplatinated(II) complexes containing fluorinated phosphine ligands: synthesis, structural characterization, and biological activity

Exploring the effect of the axial ligands on the anticancer activity of [C,N,N'] Pt(IV) cyclometallated compounds

The synthesis of three novel [C,N,N'] Pt(IV) cyclometallated compounds containing hydroxo, dichloroacetato or trifluoroacetato axial ligands is reported. Compound [PtCl(OH)2{(CH3)2N(CH2)2NCH(4-FC6H3)}] (3) was prepared by the oxidative addition of hydrogen peroxide to [C,N,N'] Pt(II) cyclometallated compound [PtCl{(CH3)2N(CH2)2NCH(4-FC6H3)}] (1) and further the reaction of compound 3 with dichloroacetate or trifluoroacetate anhydrides led to the formation of the corresponding compounds [PtCl(CHCl2COO)2{(CH3)2N(CH2)2NCH(4-FC6H3)}] (4) and [PtCl(CF3COO)2{(CH3)2N(CH2)2NCH(4-FC6H3)}] (5). The properties of the new compounds along with those of the compound [PtCl3{(CH3)2N(CH2)2NCH(4-FC6H3)}] (2), including stability in aqueous media, reduction potential using cyclic voltammetry, cytotoxic activity against the HCT116 CRC cell line, DNA interaction, topoisomerase I and cathepsin inhibition, and computational studies involving reduction of the Pt(IV) compounds and molecular docking studies, are presented. Interestingly, the antiproliferative activity of these compounds against the HCT116 CRC cell line, which is in all cases higher than that of cisplatin, follows the same trend as the reduction potentials so that the most easily reduced compound 2 is the most potent. In contrast, according to the electrophoretic mobility and molecular docking studies, the efficacy of these compounds in binding to DNA is not related to their cytotoxicity. The most active compound 2 does not modify the DNA electrophoretic mobility while the less potent compound 3 is the most efficient in binding to DNA. Although compounds 2 and 3 have only a slight effect on cell cycle distribution and apoptosis induction, generation of ROS to a higher extent for the most easily reduced compound 2 was observed.

Trans-[Pt(amine)Cl2(PPh3)] Complexes Target Mitochondria and Endoplasmic Reticulum in Gastric Cancer Cells

Gastric cancer prognosis is still notably poor despite efforts made to improve diagnosis and treatment of the disease. Chemotherapy based on platinum agents is generally used, regardless of the fact that drug toxicity leads to limited clinical efficacy. In order to overcome these problems, our group has been working on the synthesis and study of trans platinum (II) complexes. Here, we explore the potential use of two phosphine-based agents with the general formula trans-[Pt(amine)Cl2(PPh3)], called P1 and P2 (with dimethylamine or isopropylamine, respectively). A cytotoxicity analysis showed that P1 and especially P2 decrease cell viability. Specifically, P2 exhibits higher activity than cisplatin in gastric cancer cells while its toxicity in healthy cells is slightly lower. Both complexes generate Reactive Oxygen Species, produce DNA damage and mitochondrial membrane depolarization, and finally lead to induced apoptosis. Thus, an intrinsic apoptotic pathway emerges as the main type of cell death through the activation of BAX/BAK and BIM and the degradation of MCL1. Additionally, we demonstrate here that P2 produces endoplasmic reticulum stress and activates the Unfolded Protein Response, which also relates to the impairment observed in autophagy markers such as p62 and LC3. Although further studies in other biological models are needed, these results report the biomolecular mechanism of action of these Pt(II)-phosphine prototypes, thus highlighting their potential as novel and effective therapies.

Introduction of Fluorine into Antitumor-Active Dinuclear Platinum(II) Complexes Leads to Modulation of In Vivo Antitumor Activity in Mice

Tetrazolato-bridged dinuclear platinum(II) complexes ([{cis-Pt(NH₃)₂}₂(μ-OH)(μ-5-R-tetrazolato-N2,N3)]²⁺; tetrazolato-bridged complexes) show remarkable cytotoxic effects in vitro and antitumor activity in vivo. Here, we examined the structure-activity relationship of a series of fluorine-containing derivatives (R = CFH₂, CF₂H, or CF₃), focusing on their lipophilicity, cellular accumulation, cytotoxicity, interactions with a nucleobase and double-stranded deoxyribonucleic acid, and in vivo antitumor efficacy. Fluorination had a little effect on the properties of the derivatives in vitro; however, marked differences in in vitro cytotoxicity and in vivo tumor growth inhibition activity were observed. In BALB/c mice bearing colon-26 tumors, the antitumor efficacies of the derivatives were markedly altered, even by changing the number of fluorine atoms by one. In addition, one derivative, [{cis-Pt(NH₃)₂}₂(μ-OH)(μ-5-difluoromethyltetrazolato-N2,N3)](NO₃)₂, showed a significantly higher antitumor efficacy compared with oxaliplatin, a current first-line drug and the only platinum-based drug approved for the treatment of colon cancer. Together, the present results indicate that introducing fluorine into tetrazolato-bridged complexes may be useful for modulating in vivo activities.

Relevance of Fluorinated Ligands to the Design of Metallodrugs for Their Potential Use in Cancer Treatment

Fluorination of pharmaceutical agents has afforded crucial modifications to their pharmacological profiles, leading to important advances in medicinal chemistry. On the other hand, metallodrugs are considered to be valuable candidates in the treatment of several diseases, albeit with the caveat that they may exhibit pharmacological disadvantages, such as poor water solubility, low bioavailability and short circulating time. To surmount these limitations, two approaches have been developed: one based on the design of novel metallodrug-delivering carriers and the other based on optimizing the structure of the ligands bound to the metal center. In this context, fluorination of the ligands may bring beneficial changes (physicochemical and biological) that can help to elude the aforementioned drawbacks. Thus, in this review, we discuss the use of fluorinated ligands in the design of metallodrugs that may exhibit potential anticancer activity.

Luminescent cyclometalated platinum(ii) complexes with acyclic diaminocarbene ligands: structural, photophysical and biological properties

Four new cyclometalated Pt(ii) complexes bearing acyclic diaminocarbene (ADC) ligands, [Pt(C^N)Cl{C(NHXyl)(NHR)}] [C^N = 2,6-difluorophenylpyridine (dfppy), phenylquinoline (pq); R = Pr 3a, 4a, CH₂Ph 3b, 4b], were prepared by the nucleophilic attack on the isocyanide [Pt(C^N)Cl(CNXyl)] (C^N = dfppy 1, pq 2) by the corresponding amine RNH₂ (R = Pr, CH₂Ph). Complexes 3 show in their ¹H NMR spectra in CDCl₃ a notable concentration dependence, with a clear variation of the δ_H (NHXyl) signal, suggesting an assembling process implying donor-acceptor NH_XylCl bonding, also supported by 1D-PGSE (Pulse Field Gradient Spin Echo) and 2D-DOSY (Diffusion Ordered Spectroscopy) NMR experiments in solution and X-ray diffraction studies. The intermolecular interactions in compounds 3a and 3b were studied by using Hirshfeld surface analysis and Non-Covalent Interaction (NCI) methods on their X-ray structures. Their photophysical properties were investigated by absorption and emission spectroscopies and also by TD-DFT calculations performed on 3a and 4b. These complexes show green (3) or orange (4) phosphorescence, attributed to a mixed ³IL/³MLCT excited state. The carbene ligand does not affect the emission maxima but it produces an increase of the quantum yields in relation to the isocyanide in the precursors. In fluid solutions, the emission is not concentration-dependent, but the complexes may show aggregation induced emission as detailed for complexes 3a and 4a. In addition, cytotoxicity studies in the human cell lines A549 (lung carcinoma) and HeLa (cervix carcinoma) showed good activity for these complexes and 3a, 3b and 4a exhibit a strong effect on DNA electrophoretic mobility. To the best of our knowledge, compounds 3 and 4 represent the first examples of cycloplatinated complexes bearing acyclic diamino carbenes with antiproliferative properties.

In Vitro and In Vivo Effect of Palladacycles: Targeting A2780 Ovarian Carcinoma Cells and Modulation of Angiogenesis

Palladacycles are versatile organometallic compounds that show potential for therapeutic use. Here are described the synthesis and characterization of mono- and dinuclear palladacycles bearing diphosphines. Their biological effect was investigated in A2780, an ovarian-derived cancer line, and in normal dermal fibroblasts. The compounds displayed selective cytotoxicity toward the A2780 cell line. Compound 3 decreased the cell viability through cell cycle retention in G0/G1, triggered apoptosis through the intrinsic pathway, and induced autophagy in A2780 cells. Compound 9 also induced cell cycle retention, apoptosis, and cellular detachment. Notably, compound 9 induced the production of intracellular reactive oxygen species (ROS). Our work demonstrated that compound 3 enters A2780 cells via active transport, which requires energy, while compound 9 enters A2780 cells mostly passively. The potential effect of palladacycles in angiogenesis was investigated for the first time in an in vivo chorioallantoic membrane model, showing that while compound 3 displayed an antiangiogenic effect crucial to fighting cancer progression, compound 9 promoted angiogenesis. These results show that palladacycles may be used in different clinical applications where pro- or antiangiogenic effects may be desirable.

Fluorinated Cycloplatinated(II) Complexes Bearing Bisphosphine Ligands as Potent Anticancer Agents

A family of cationic cycloplatinated(II) complexes [Pt(dfppy)(P^P)]Cl, dfppy = 2-(2,4-difluorophenyl)pyridine, incorporating bisphosphine ligands, P^P = bis(diphenylphosphino)methane (1, dppm), 1,2-bis(diphenylphosphino)ethane (2, dppe) and 1,2-bis(diphenylphosphino)benzene (3, dppbz), was prepared. The complexes were characterized by means of several analytical and spectroscopic methods. These complexes displayed acceptable stability in the biological environments which was confirmed by NMR, HR ESI-MS and UV-vis techniques. The antiproliferative properties of these complexes were evaluated by National Cancer Institute (NCI) at National Institutes of Health (NIH) against 60 different human tumor cell lines such as leukemia, melanoma, lung, colon, brain, ovary, breast, prostate and kidney. These complexes showed higher cytotoxicity than cisplatin against a wide variety of cancer cell lines such as K-562 (leukemia), HOP-92 (lung), HCT-116 (colon), OVCAR-8 (ovarian), PC-3 (prostate), MDA-MB-468 (breast), and melanoma cancer cell lines. Complex 3 as the most potent compound in this study furnished an excellent anti-proliferative activity compared to the cisplatin against Hela, SKOV3, and MCF-7 cancer cell lines. The main mode of the interaction of 1-3 with DNA was also determined using molecular docking studies.

Pentafluorophenyl Platinum(II) Complexes of PTA and its N-Allyl and N-Benzyl Derivatives: Synthesis, Characterization and Biological Activity

From the well-known 1,3,5-triaza-phosphaadamantane (PTA, 1a), the novel N-allyl and N-benzyl tetrafuoroborate salts 1-allyl-1-azonia-3,5-diaza-7-phosphaadamantane (APTA(BF₄), 1b) and 1-benzyl-1-azonia-3,5-diaza-7-phosphaadamantane (BzPTA(BF₄), 1c) were obtained. These phosphines were then allowed to react with (Pt(μ-Cl)(C₆F₅)(tht))₂ (tht = tetrahydrothiophene) affording the water soluble Pt(II) complexes trans-(PtCl(C₆F₅)(PTA)₂) (2a) and its bis-cationic congeners trans-(PtCl(C₆F₅)(APTA)₂)(BF₄)₂ (2b) and trans-(PtCl(C₆F₅)(BzPTA)₂)(BF₄)₂ (2c). The compounds were fully characterized by multinuclear NMR, ESI-MS, elemental analysis and (for 2a) also by single crystal X-ray diffraction, which proved the trans configuration of the phosphine ligands. Furthermore, in order to evaluate the cytotoxic activities of all complexes the normal human dermal fibroblast (NHDF) cell culture were used. The antineoplastic activity of the investigated compounds was checked against the human lung carcinoma (A549), epithelioid cervix carcinoma (HeLa) and breast adenocarcinoma (MCF-7) cell cultures. Interactions between the complexes and human serum albumin (HSA) using fluorescence spectroscopy and circular dichroism spectroscopy (CD) were also investigated.

Fluorine-Substituted Arylphosphine for an NHC-Ni(I) System, Air-Stable in a Solid State but Catalytically Active in Solution

Monovalent NHC-nickel complexes bearing triarylphosphine, in which fluorine is incorporated onto the aryl groups, have been synthesized. Tris(3,5-di(trifluoromethyl)-phenyl)phosphine efficiently gave a monovalent nickel bromide complex, whose structure was determined by X-ray diffraction analysis for the first time. In the solid state, the Ni(I) complex was less susceptible to oxidation in air than the triphenylphosphine complex, indicating greatly improved solid-state stability. In contrast, the Ni(I) complex in solution can easily liberate the phosphine, high catalytic activity toward the Kumada-Tamao-Corriu coupling of aryl bromides.

Structures and anticancer activity of chlorido platinum(II) saccharinate complexes with mono- and dialkylphenylphosphines

cis-[PtCl(sac)(PPh₂Me)₂] (1), cis-[PtCl(sac)(PPhMe₂)₂] (2), trans-[PtCl(sac)(PPh₂Et)₂] (3) and trans-[PtCl(sac)(PPhEt₂)₂] (4) complexes (sac = saccharinate) were synthesized and characterized by elemental analysis and spectroscopic methods. The structures of 2-4 were determined by X-ray single-crystal diffraction. The interaction of the complexes with DNA was studied various biochemical, biophysical and molecular docking methods. Only the cis-configured complexes (1 and 2) showed nuclease activity and their binding affinity towards DNA was considerably higher than those of their trans-congeners (3 and 4). The chlorido ligand in the cis-configured complexes underwent aquation, making them more reactive towards DNA. Furthermore, 1 and 2 exhibited anticancer potency on breast (MCF-7) and colon (HCT116) cancer cells similar to cisplatin, whereas 3 and 4 were biologicallly inactive. Mechanistic studies on MCF-7 cells showed that higher nuclear uptake, cell cycle arrest at the S phase, dramatically increased DNA double-strand breaks, apoptosis induction, elevated levels of reactive oxygen species (ROS) and high mitochondrial membrane depolarization greatly contribute to the anticancer potency of 1 and 2.

Benzothiazole-Based Cycloplatinated Chromophores: Synthetic, Optical, and Biological Studies

Cycloplatinated complexes based on 2-(4-substituted)benzothiazole ligands of type [Pt(R-PBT-κC,N)Cl(L)] (PBT=2-phenylbenzothiazole; R=Br (1), Me₂ N (2); L=dimethyl sulfoxide (DMSO; a), 1,3,5- triaza-7-phosphaadamantane (PTA; b), triphenylphosphine 3,3',3''-trisulfonate (TPPTS; c)) and [Pt(Br-PBT-κC)Cl(PTA)₂ ] (3) are presented. On the basis of the photophysical data and time-dependent (TD)-DFT calculations (1 a and 2 a), the low-lying transitions (absorption and emission) were associated with ligand-center (LC) charge transfer, with minor metal-to-ligand charge transfer (MLCT), and intraligand charge transfer (ILCT) [Me₂ N-PBT→PBT] excited states, respectively. Simultaneous fluorescence/phosphorescence bands were found in fluid solutions (and also in the solid state for 2 a), which become dominated by triplet emission bands in rigid media at 77 K. The effect of the concentration on emissive behavior of 2 a, b indicated the occurrence of aggregation-induced luminescence properties related to the occurrence of metal-metal and π⋅⋅⋅π interactions, which are more enhanced in 2 a because of the less bulky DMSO ligand. The behavior of 2 a toward para-toluenesulfonic acid (PTSA) in aerated acetonitrile and to hydrogen chloride gas in the solid state has been evaluated, thus showing a clear reversible change between the ¹ ILCT and ³ LC/³ MLCT states due to protonation of the NMe₂ group (theoretical calculations on 2 a-H⁺ ). Solid 2 a undergoes a surprising oxidation of the Pt^II center to Pt^IV with concomitant deoxygenation of DMSO, under prolonged reaction with hydrogen chloride gas to afford the Pt^IV /dimethyl sulfide complex (mer-[Pt(Me₂ N-PBT-κC,N)Cl₃ (SMe₂ )]; mer-4), which evolves in solution to fac-4, as confirmed by X-ray studies. Cytotoxic activity studies on A549 and HeLa cell lines indicated cytotoxic activity of 1 b and 2 a, b. In addition, fluorescent cell microscopy revealed cytoplasmic staining, more visible in perinuclear areas. Inhibition of tubulin polymerization by 1 b in both cells is presented as a preliminary mechanism of its cytotoxic action.

9,9-Difluorobispidine Analogues of Cisplatin, Carboplatin, and Oxaliplatin

As part of a comprehensive study of N-unsubstituted bispidines, the novel 9,9-difluorobispidine (D) has been synthesized. The compound crystallizes from pentane below 0 °C in the ordered-crystalline phase D-II and undergoes at 0-30 °C a stepwise endothermic phase transition to a dynamically disordered crystalline phase D-I; melting occurs at 227 °C. Single crystalline D-II has been subjected to X-ray structure analysis, revealing association of the molecules to form chains. Reaction of (1,5-hexadiene)PtCl₂ with D affords {C₇H₁₀F₂(NH)₂}PtCl₂ (D1), which can be converted by conventional routes to {C₇H₁₀F₂(NH)₂}Pt(cbdca)·5H₂O (D2) and {C₇H₁₀F₂(NH)₂}Pt(C₂O₄) (D3). Compound D1 crystallizes solvent-free from water and is isomorphous to the solvent-free parent bispidine analogue (A1). The pentahydrate D2 is isomorphous to the bispidine and 9-oxabispidine homologues (A2 and C2), as shown by X-ray structure analyses. An increased polarity of the bispidine skeleton as a consequence of the high electronegativity of fluorine is seen as the reason for low cytotoxic potency of D1-D3.

On the stability and biological behavior of cyclometallated Pt(IV) complexes with halido and aryl ligands in the axial positions

A series of cyclometallated platinum(IV) compounds (3a, 3a' and 3b') with a meridional [C,N,N'] terdentate ligand, featuring an halido and an aryl group in the axial positions has been evaluated for electrochemical reduction and preliminary biological behavior against a panel of human adenocarcinoma (A-549 lung, HCT-116 colon, and MCF-7 breast) cell lines and the normal bronquial epithelial BEAS-2B cells. Cathodic reduction potentials (shifting from -1.463 to -1.570V) reveal that the platinum(IV) compounds under study would be highly reluctant to be reduced in a biological environment. Actually ascorbic acid was not able to reduce complex 3a', the most prone to be reduced according its reduction potential, over a period of one week. These results suggest an intrinsic activity for the investigated platinum(IV) complexes (3a, 3a' and 3b'), which exhibit a remarkable cytotoxicity effectiveness (with IC₅₀ values in the low micromolar range), even greater than that of cisplatin. The IC₅₀ for A-549 lung cells and clog P values were found to follow the same trend: 3b'>3a'>3a. However, no correlation was observed between reduction potential and in vitro activity. As a representative example, cyclometallated platinum(IV) compound 3a', exercise its antiproliferative activity directly over non-microcytic A-549 lung cancer cells through a mixture of cell cycle arrest (13% arrest at G1 phase and 46% arrest at G2 phase) and apoptosis induction (increase of early apoptosis by 30 times with regard to control). To gain further insights into the mode of action of the investigated platinum(IV) complexes, drug uptake, cathepsin B inhibition and ROS generation were also evaluated. Interestingly an increased ROS generation could be related with the antiproliferative activity of the cyclometallated platinum(IV) series under study in the cisplatin-resistant A-549 lung and HCT-116 cancer cell lines.

Neutral and ionic platinum compounds containing a cyclometallated chiral primary amine: synthesis, antitumor activity, DNA interaction and topoisomerase I-cathepsin B inhibition

The synthesis and preliminary biological evaluation of neutral and cationic platinum derivatives of chiral 1-(1-naphthyl)ethylamine are reported, namely cycloplatinated neutral complexes [PtCl{(R or S)-NH(2)CH(CH(3))C(10)H(6)}(L)] [L = SOMe(2) ( 1-R or 1-S ), L = PPh(3) (2-R or 2-S), L = P(4-FC(6)H(4))(3) (3-R), L = P(CH(2))(3)N(3)(CH(2))(3) (4-R)], cycloplatinated cationic complexes [Pt{(R)-NH(2)CH(CH(3))C(10)H(6)}{L}]Cl [L = Ph(2)PCH(2)CH(2)PPh(2) (5-R), L = (C(6)F(5))(2)PCH(2)CH(2)P(C(6)F(5))(2) (6-R)] and the Pt(ii) coordination compound trans-[PtCl(2){(R)-NH(2)CH(CH(3))C(10)H(6)}(2)] (7-R). The X-ray molecular structure of 7-R is reported. The cytotoxic activity against a panel of human adenocarcinoma cell lines (A-549 lung, MDA-MB-231 and MCF-7 breast, and HCT-116 colon), cell cycle arrest and apoptosis, DNA interaction, topoisomerase I and cathepsin B inhibition, and Pt cell uptake of the studied compounds are presented. Remarkable cytotoxicity was observed for most of the synthesized Pt(ii) compounds regardless of (i) the absolute configuration R or S, and (ii) the coordinated/cyclometallated (neutral or cationic) nature of the complexes. The most potent compound 2-R (IC(50) = 270 nM) showed a 148-fold increase in potency with regard to cisplatin in HCT-116 colon cancer cells. Preliminary biological results point out to different biomolecular targets for the investigated compounds. Neutral cyclometallated complexes 1-R and 2-R, modify the DNA migration as cisplatin, cationic platinacycle 5-R was able to inhibit topoisomerase I-promoted DNA supercoiling, and Pt(ii) coordination compound 7-R turned out to be the most potent inhibitor of cathepsin B. Induction of G-1 phase ( 2-R and 5-R ), and S and G-2 phases (6-R) arrests are related to the antiproliferative activity of some representative compounds upon A-549 cells. Induction of apoptosis is also observed for 2-R and 6-R.

Novel C,N-Cyclometalated Benzimidazole Ruthenium(II) and Iridium(III) Complexes as Antitumor and Antiangiogenic Agents: A Structure-Activity Relationship Study

A series of novel C,N-cyclometalated benzimidazole ruthenium(II) and iridium(III) complexes of the types [(η(6)-p-cymene)RuCl(κ(2)-N,C-L)] and [(η(5)-C5Me5)IrCl(κ(2)-N,C-L)] (HL = methyl 1-butyl-2-arylbenzimidazolecarboxylate) with varying substituents (H, Me, F, CF3, MeO, NO2, and Ph) in the R4 position of the phenyl ring of 2-phenylbenzimidazole chelating ligand of the ruthenium (3a-g) and iridium complexes (4a-g) have been prepared. The cytotoxic activity of the new ruthenium(II) and iridium(III) compounds has been evaluated in a panel of cell lines (A2780, A2780cisR, A427, 5637, LCLC, SISO, and HT29) in order to investigate structure-activity relationships. Phenyl substitution at the R4 position shows increased potency in both Ru and Ir complexes (3g and 4g, respectively) as compared to their parent compounds (3a and 4a) in all cell lines. In general, ruthenium complexes are more active than the corresponding iridium complexes. The new ruthenium and iridium compounds increased caspase-3 activity in A2780 cells, as shown for 3a,d and 4a,d. Compound 4g is able to increase the production of ROS in A2780 cells. Furthermore, all the new compounds are able to overcome the cisplatin resistance in A2780cisR cells. In addition, some of the metal complexes effectively inhibit angiogenesis in the human umbilical vein endothelial cell line EA.hy926 at 0.5 μM, the ruthenium derivatives 3g (Ph) and 3d (CF3) being the best performers. QC calculations performed on some ruthenium model complexes showed only moderate or slight electron depletion at the phenyl ring of the C,N-cyclometalated ligand and the chlorine atom on increasing the electron withdrawing effect of the R substituent.

Cyclometalated Iminophosphorane Gold(III) and Platinum(II) Complexes. A Highly Permeable Cationic Platinum(II) Compound with Promising Anticancer Properties

New organometallic gold(III) and platinum(II) complexes containing iminophosphorane ligands are described. Most of them are more cytotoxic to a number of human cancer cell lines than cisplatin. Cationic Pt(II) derivatives 4 and 5, which differ only in the anion, Hg₂Cl₆^2– or PF₆^– respectively, display almost identical IC₅₀ values in the sub-micromolar range (25–335-fold more active than cisplatin on these cell lines). The gold compounds induced mainly caspase-independent cell death, as previously reported for related cycloaurated compounds containing IM ligands. Cycloplatinated compounds 3, 4, and 5 can also activate alternative caspase-independent mechanisms of death. However, at short incubation times cell death seems to be mainly caspase dependent, suggesting that the main mechanism of cell death for these compounds is apoptosis. Mercury-free compound 5 does not interact with plasmid (pBR322) DNA or with calf thymus DNA. Permeability studies of 5 by two different assays, in vitro Caco-2 monolayers and a rat perfusion model, have revealed a high permeability profile for this compound (comparable to that of metoprolol or caffeine) and an estimated oral fraction absorbed of 100%, which potentially makes it a good candidate for oral administration.

The structural and electronic impact on the photophysical and biological properties of a series of CuI and AgI complexes with triphenylphosphine and pyrimidine-type thiones

A controllable S,P-coordination environment resulting in selective structural, emissive and antibacterial properties.