Correction: In vitro and in vivo antiproliferative activity of organo-nickel SCS-pincer complexes on estrogen responsive MCF7 and MC4L2 breast cancer cells. Effects of amine fragment substitutions on BSA binding and cytotoxicity.

Correction for 'In vitro and in vivo antiproliferative activity of organo-nickel SCS-pincer complexes on estrogen responsive MCF7 and MC4L2 breast cancer cells. Effects of amine fragment substitutions on BSA binding and cytotoxicity' by Mahboubeh Hosseini-Kharat et al., Dalton Trans., 2018, 47, 16944-16957, https://doi.org/10.1039/c8dt03079k.

Resistance Improvement and Sensitivity Enhancement of Cancer Therapy by a Novel Antitumor Candidate onto A2780 CP and A2780 S Cell Lines.

Background: To overcome cisplatin resistance, the cytotoxicity of a novel antitumor agent on two ovarian cancer cell lines sensitive and resistant to cisplatin was investigated. Methods: MTT assay and flow cytometry were performed to assess the cytotoxicity of a novel water-soluble Pd (II) complex, [Pd(bpy)(pyr-dtc)]NO3 (PBPD), on cisplatin-sensitive and cisplatin-resistant ovarian cancer cell lines. Furthermore, variations in the expression of drug resistance gene cluster of differentiation 99 (CD99), signal transducer and activator of transcription 3 (STAT3), octamer-binding transcription factor 4 (OCT4), and multidrug resistance mutation 1 (MDR1) were evaluated using Real-Time PCR. Results: The IC50 values of PBPD in resistant cells were higher than those in sensitive cells. Furthermore, PBPD has a deadlier effect on sensitive cells compared to resistant cells, and the cell survival rate is reduced over time. Flow cytometry revealed that PBPD enhanced the population of living-resistant cells while driving them to apoptosis. PBPD, on the other hand, has a greater effect on the living cell population and has dramatically shifted the population toward apoptosis and necrosis in the sensitive cells. Furthermore, gene expression analysis showed that when sensitive and resistant cells were treated with cisplatin, all resistance genes increased significantly relative to the control. In contrast to OCT4, MDR1, STAT3, and CD99 resistance genes were not significantly elevated in sensitive cells treated with PBPD compared to the control. Thus, the expression of resistance genes in resistant cells treated with PBPD was lower than cisplatin. Conclusions: As a result, PBPD is a promising anticancer agent for CDDP-resistant ovarian cancer.

Sustained release of sulforaphane by bioactive extracellular vesicles for neuroprotective effect on chick model.

Novel studies have shown neurological treatment possibilities with extracellular vesicles (EVs) as natural particles with a special composition that are produced by different cell types. Their stability, natural structure, composition, and bioavailability make them good candidates as drug vehicles. Here, EVs were isolated from amniotic fluid (AF) through differential centrifugation, and characterized for size (<200 nm), structure, and composition, their effectiveness on the human PC12 cell line, and brain of chick embryos exposed to sodium valproate (animal autistic model). Sulforaphane (SFN) was employed as a bioactive compound and then encapsulated into Evs using three methods including passive (incubation), active (sonication), and active-passive (sonication-incubation). Further, the loading and in vitro releases of SFN fitted the Korsmeyer-Peppas (R2  = 0.99) kinetic model by non-Fickian diffusion case II (n = 0.44, passive loading) and Fickian diffusion case I (n = 0.41, active and active-passive loading). SFN-loaded EVs (SFN@EVs; 11 µM: 103 nM) stimulated hPC-12 cell proliferation. The gene expression analysis revealed that SFN@EVs could upregulate Nrf2 and reduce IL-6 expression. Eventually, histopathological results of the coronal cross-section of the chick embryos brain showed treatment with SFN@EVs. This treatment illustrated normality in the gray and white matter and the orientation of the bipolar neurons. Our findings showed EVs' potentially acting as a gene expression regulator in autism spectrum disorder.

Synthesis, characterization, cytotoxicity and DNA/BSA binding of two amino acid palladium(II) complexes derived from alanine and valine.

Two novel palladium(II)-amino acid complexes, [Pd(Ala)2]·H2O (PA) and [Pd(Val)2].H2O (PV) (Ala = alanine; Val = valine) were synthesized and characterized through FTIR, UV/Vis, 1H-NMR spectroscopies, CHN analysis, X-ray crystallography and molar conductivity measurement. Furthermore, cytotoxicity of Pd(II) complexes against human leukemia cancer cell line, MOLT4 showed promising cancer cell death (CC50 = 0.71 ± 0.046 µM for PA; CC50 = 0.85 ± 0.063 µM for PV) that were less than cisplatin (1.59 ± 0.25 µM). Moreover, the interaction of both the complexes with DNA and BSA was studied using UV-Vis absorption and emission spectroscopic techniques that demonstrated the bindings occurred via van der Waals forces and hydrogen bond. Furthermore, the fluorescence titration showed that static quenching mechanism plays predominate role in binding process. All results showed that both complexes have more binding tendency to DNA in compared to BSA that can be a significant achievement for further medical purposes as a potential antitumor candidate. Finally, molecular docking simulation was performed for PA and PV complexes with DNA and BSA and demonstrated both complexes bind to the groove of DNA mainly by hydrogen bond and interact with site I of BSA via hydrogen bond as well.

3D Bioprinting of Polycaprolactone-Based Scaffolds for Pulp-Dentin Regeneration: Investigation of Physicochemical and Biological Behavior.

In this study, two structurally different scaffolds, a polycaprolactone (PCL)/45S5 Bioglass (BG) composite and PCL/hyaluronic acid (HyA) were fabricated by 3D printing technology and were evaluated for the regeneration of dentin and pulp tissues, respectively. Their physicochemical characterization was performed by field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), contact angle, and compressive strength tests. The results indicated that the presence of BG in the PCL/BG scaffolds promoted the mechanical properties, surface roughness, and bioactivity. Besides, a surface treatment of the PCL scaffold with HyA considerably increased the hydrophilicity of the scaffolds which led to an enhancement in cell adhesion. Furthermore, the gene expression results showed a significant increase in expression of odontogenic markers, e.g., dentin sialophosphoprotein (DSPP), osteocalcin (OCN), and dentin matrix protein 1 (DMP-1) in the presence of both PCL/BG and PCL/HyA scaffolds. Moreover, to examine the feasibility of the idea for pulp-dentin complex regeneration, a bilayer PCL/BG-PCL/HyA scaffold was successfully fabricated and characterized by FESEM. Based on these results, it can be concluded that PCL/BG and PCL/HyA scaffolds have great potential for promoting hDPSC adhesion and odontogenic differentiation.

A new palladium-based antiproliferative agent: synthesis, characterization, computational calculations, cytotoxicity, and DNA binding properties.

A new palladium(II) complex entitled [Pd(phendione)(8Q)]NO3, (PdPQ), where phendione is N,N-donor heterocyclic 1,10-phenanthroline-5,6-dion and 8Q is 8-hydroxyquinolinate, has been synthesized and then characterized by molar conductivity, CHN analysis and spectral data (UV-Vis, FT-IR, NMR). DFT/ TDDFT procedures were also performed to determine the electronic structure and the nature of the electronic transitions of PdPQ. Moreover, the affinity and binding properties of DNA to the desired complex have been studied in details using electronic absorption, fluorescence, circular dichroism spectroscopies, and viscosity measurement in combination with molecular docking technique. The obtained results exhibit relatively high DNA binding values with a static quenching mechanism, which suggest that an intercalative mode plays a peridominate role in interaction process concluded by experimental/theoretical measurements. As a result of drug exposure, in vitro cytotoxicity assay demonstrated the antiproliferative activity of the PdPQ against leukemia cancer cell line, K562.

The simultaneous carrier ability of natural antioxidant of astaxanthin and chemotherapeutic drug of 5-fluorouracil by whey protein of ß-lactoglobulin: spectroscopic and molecular docking study.

In the present study, the simultaneous carrier ability of natural antioxidant of astaxanthin (ATX) and chemotherapeutic drug of 5-fluorouracil (5-FU) by whey protein of ß-lactoglobulin (ß-LG) using various spectroscopic techniques (UV-visible, fluorescence, circular dichroism (CD) and dynamic light scattering) in combination with molecular docking were investigated (at room and physiological temperatures). According to the fluorescence quenching tests, the binding parameters between drug and ATX with protein showed that the number of their binding sites was the same in the single and competitive states. Molecular docking results have showed completely consistent with the fluorescence data that presented the independent binding sites for 5-FU and ATX on ß-LG. Also, analysis of Far-UV-CD showed that the simultaneous binding of the drugs to the protein partially enhances its stability, which is associated with the decreasing in ß-sheet structure and increasing in α-helix. According to the Zeta potential measurements in the presence of different concentrations of the drugs, they have stronger binding to the protein at lower concentrations. Therefore, given the remarkable features of ß-LG, including the ability to interact simultaneously with the natural compound of ATX and the antitumor drug of 5-FU, this study could provide useful information for the development and improvement of new protein carrier systems with synergism potency. Communicated by Ramaswamy H. Sarma.

Increasing the effectiveness of oxaliplatin using colloidal immunoglobulin G nanoparticles: Synthesis, cytotoxicity, interaction, and release studies.

A novel biomacromolecule was prepared for a stabilizer sustained anticancer drug release system. Colloidal immunoglobulin G (IgG) nanoparticles (IgGNP) were synthesized and then characterized using FT-IR, SEM, zeta sizer, and AFM. Moreover, the formation of spherical shape IgGNP with an appropriate average size (144.56 ± 2 nm) and a narrow distribution for the drug release was confirmed. Also, the conjugation of oxaliplatin (OX) to IgGNP (OX@IgGNP) was demonstrated via the combination of spectroscopy and physical analyses. In this regard, the interaction was spantaneous with static quenching mechanism. OX caused well dispersity with no agglomeration on IgGNP with an average size of 142.31 ± 4 nm. Furthermore, the encapsulation efficiency (%EE) and drug loading (%DL) percentages were determined. Accordingly, the release behavior indicated that OX was sustained from IgGNP more than IgG (approximately 150 h) and the highest release amount of OX (100 %) was obtained at acidic medium (pH 5.5). Notably, the kinetic model was zero order and release mechanism followed by diffusion and Fick's model at neutral medium and combination of diffusion and swelling controlled and non-Fickian model at acidic medium. In addition, the anticancer effect of OX@IgGNP was evaluated on the human breast cancer cell lines, MCF-7 using MTT assay and DAPI staining that showed a remarkable efficacy, while the cytotoxicity in human fibroblast cell lines, HFFF2 has decreased. In this study, gene expression was investigated using real time PCR, which verified IgGNP induced programmed cell death in MCF-7 breast cancer cell more effectively than free OX. Subsequently, a novel nano scale biological macromolecule can be introduced as a sustained and prolonged anticancer drug release.

Catalytic activity and structural changes of catalase in the presence of Levothyroxine and Isoxsuprine hydrochloride.

Two drugs that pregnant women (with hypothyroidism) may use during pregnancy include Isoxsuprine hydrochloride (ISO) and levothyroxine (LEV); ISO to reduce uterine contractions and LEV for the treatment of hypothyroidism. In the current work, we explored the mechanism of binding affinity between the above drugs and antioxidant enzyme Bovine Liver Catalase (BLC). The experimental results confirmed that both drugs could bind with BLC to form drug-BLC complexes but LEV showed a higher binding affinity toward enzyme. The binding constants of LEV-and ISO-BLC were 0.42 × 105 and 0.13 × 104 M-1 at 310 K, respectively. LEV enhanced the catalase activity but the enzymatic activity of BLC reduced gradually in the presence of ISO. Both drugs were able to induce conformational changes in the BLC structure. The results of the molecular docking investigations confirmed the experimental data and showed that the main binding forces in the LEV-BLC and ISO-BLC systems were hydrogen bond and hydrophobic force. The best binding site of both drugs on BLC is located at a cavity among the wrapping domain, N-Terminal arm, and ß-barrel.

Improvement of efficacy and decrement cytotoxicity of oxaliplatin anticancer drug using bovine serum albumin nanoparticles: synthesis, characterisation and release behaviour.

To sustained release of an anticancer drug, oxaliplatin (OX), a non-toxic and biocompatible nanocarrier based on bovine serum albumin (BSA) were synthesised by desolvation method and characterised using Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and dynamic light scattering. The results showed that the BSA nanoparticles (BSANPs) with a mean magnitude of 187.9 ± 1.2 nm have spherical morphology with a smooth surface and a uniform distribution. Furthermore, OX was loaded onto the BSANPs and the loading was confirmed by FTIR, AFM and FESEM techniques. The percentage of encapsulation efficiency and drug loading were determined by absorption spectroscopy (UV-vis). The drug release studies showed that release of OX from BSANPs exhibited slower release rate. However, the release kinetics followed the first-order kinetic for both of them with the non-Fickian release behaviour. The electrochemical analysis showed stability of OX loaded onto the BSANPs (OX@BSANPs) and confirmed the diffusion mechanism. Furthermore, the results of MTT assay revealed increasing of normal cell viability and cancer cell death in the OX@BSANPs compared to only OX. It was shown that the BSANPs could be safely used as a biocompatible nanocarrier for the sustained release of OX.

Interaction, cytotoxicity and sustained release assessment of a novel anti-tumor agent using bovine serum albumin nanocarrier.

The interaction ability of bovine serum albumin (BSA) with 2,6-divanillylidenecyclohexanone (DVH) as a stable curcumin derivative was investigated using fluorescence and circular dichroism (CD) spectroscopy techniques under simulative physiological conditions (pH = 7.2). Following the obtained results of binding studies, bovine serum albumin nanoparticles (BSANPs) were synthesized and characterized using Fourier transform infrared spectroscopy (FT-IR), filed emission scanning electron microscopy (FE-SEM), atomic force microscope (AFM) and dynamic light scattering (DLS). The stable BSANPs showed a spherical shape with a diameter of 149.14 ± 46.69 nm and the formulation of BSA had no change during the fabrication process. DVH was loaded on BSANPs (DVH@BSANPs) and the release studies showed sustained release of DVH from BSANPs. The validation of DVH@BSANPs system confirmed that the Fickian release mechanism of DVH followed on Korsmeyer-Pepas model. The in vitro studies on HFFF2 and MDA-MB-231 were investigated using MTT assay, DAPI and annexinV/PI staining that showed biocompatible BSANPs reduced the cytotoxicity of DVH in normal cell lines significantly, and antitumor activity of DVH was increased when it was loaded onto BSANPs without necrosis. These results suggest that DVH@BSANPs are a novel biocompatible sustained release system for effective therapeutic approach.Communicated by Ramaswamy H. Sarma.

Nonionic but water soluble, [Glycine-Pd-Alanine] and [Glycine-Pd-Valine] complexes. Their synthesis, characterization, antitumor activities and rich DNA/HSA interaction studies.

Two novel, neutral and water soluble Pd(II) complexes of formula [Pd(Gly)(Ala)] (1) and [Pd(Gly)(Val)] (2) (Gly, Ala, and Val are anionic forms of glycine, alanine, and valine amino acids, respectively) have been synthesized and characterized by FT-IR, UV-Vis, 1H-NMR, elemental analysis, and molar conductivity measurement. The data revealed that each amino acid binds to Pd(II) through the nitrogen of -NH2 and the oxygen of -COO- groups and acts as a bidentate chelate. These complexes have been assayed against leukemia cells (K562) using MTT method. The results indicated that both of the complexes display more cytotoxicity than the well-known anticancer drug, cisplatin. The interaction of the compounds with calf thymus DNA (CT-DNA) and human serum albumin (HSA) were assayed by a series of experimental techniques including electronic absorption, fluorescence, viscometry, gel electrophoresis, and FT-IR. The results indicated that the two complexes have interesting binding propensities toward CT-DNA as well as HSA and the binding affinity of (1) is more than (2). The fluorescence data indicated that both complexes strongly quench the fluorescence of ethidium bromide-DNA system as well as the intrinsic fluorescence of HSA via static quenching procedures. The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) calculated from the fluorescence studies showed that hydrogen bonds and van der Waals interactions play a major role in the binding of the complexes to DNA and HSA. We suggest that both of the Pd(II) complexes exhibit the groove binding mode with CT-DNA and interact with the main binding pocket of HSA. Communicated by Ramaswamy H. Sarma.

In vitro and in vivo antiproliferative activity of organo-nickel SCS-pincer complexes on estrogen responsive MCF7 and MC4L2 breast cancer cells. Effects of amine fragment substitutions on BSA binding and cytotoxicity.

A family of organonickel complexes has been prepared, fully characterized, and tested for their antiproliferative activity against estrogen-responsive human breast cancer cells (MCF7). The three SCS-type pincer ligands HL1, HL2, and HL3 and their corresponding Ni(ii) complexes NiL1, NiL2, and NiL3 have been synthesized and fully characterized, including by single crystal diffraction studies for the complexes. The complexes possess square planar geometry with two symmetrical 5-membered nickellacycles. Fluorescence spectroscopy, circular dichroism measurements, molecular modeling, colorimetric based assay and tumor transplantation studies were used to evaluate the protein binding and antiproliferative activities of these organometallic complexes both in vitro and in vivo. Fluorescence quenching was used to investigate bovine serum albumin (BSA) interaction at different temperatures (293, 303 and 313 K), and the results were analyzed using the classical Stern-Volmer equation, allowing us to propose a dynamic quenching mechanism. Studies in vitro on the antiproliferative activity of the three organonickel complexes against estrogen-responsive human breast cancer cells (MCF7) showed promising antitumor activity for NiL1 containing pyrrolidine fragments. In vivo administration of this compound significantly inhibits tumor growth in estrogen-dependent MC4L2 cancer cells in female BALB/c mice.

Biological effect and molecular docking of anticancer palladium and platinum complexes with morpholine dithiocarbamate on human serum albumin as a blood carrier protein.

The aim of this study was to examine the interaction of [Pd(2,2'-bipyridine) (morpholinedithiocarbamate)]NO3 and [Pt (2,2'-bipyridine)(morpholinedithiocarbamate)]NO3 with human serum albumin under physiological conditions by using fluorescence, absorption, and circular dichroism spectroscopic techniques. Spectroscopic analysis of the emission quenching at different temperatures demonstrated that the quenching mechanism was static quenching. From the circular dichroism results, thermal stability study, it was found that the interaction of the complexes with human serum albumin caused a conformational change of the protein reversibly. These 2 anticancer Pd and Pt complexes were activated against chronic myelogenous leukemia cell line K562, so that 50% cytotoxic concentration values of 16 and 26 µM for Pd and Pt complexes, respectively, were observed, which were much lower than that of cisplatin (154 µM). Biological activities of both Pd and Pt complexes were also assayed against selective microorganisms by the disc diffusion method. These results showed that the Pd(II) complex is antifungal agent but Pt(II) complex has antibacterial activity. Also, the interaction of both metal derivative complexes was studied by molecular docking. Complementary molecular docking results may be useful to determine the binding mechanism of human serum albumin in pharmaceutical and biophysical studies providing new insight in the novel pharmacology.

Synthesis, characterization, in silico ADMET prediction, and protein binding analysis of a novel zinc(II) Schiff-base complex: Application of multi-spectroscopic and computational techniques.

By reaction of 1,2-diaminocyclohexane with the 2,3-butanedione monoxime in the presence of ZnCl2, a new Schiff base complex was obtained. This complex was characterized by elemental analyses, FT-IR, 1H NMR, UV-Vis, and conductivity measurements. The reactivity of this complex to human serum albumin (HSA) under simulative physiological conditions was studied by spectroscopic and molecular docking analysis. Experimental results at various temperatures indicated that the intrinsic fluorescence of protein was quenched through a static quenching mechanism. The negative value of enthalpy change and positive value of entropy change indicated that both hydrogen bonding and hydrophobic forces played a major role in the binding of Zn(II) complex to HSA. FT-IR, three-dimensional fluorescence, and UV-Vis absorption results showed that the secondary structure of HSA changed after Zn(II) complex bound to protein. The binding distance was calculated to be 4.96 nm, according to fluorescence resonance energy transfer. Molecular docking results confirmed the spectroscopic results and showed that above complex is embedded into subdomain IIA of protein. All these experimental and computational results clarified that Zn(II) complex could bind with HSA effectively, which could be a useful guideline for efficient Schiff-base drug design.

Biophysical and computational comparison on the binding affinity of three important nutrients to ß-lactoglobulin: folic acid, ascorbic acid and vitamin K3.

Small globular protein, ß-lactoglobulin (ßLG), which has significant affinity toward many drugs, is the most abundant whey protein in milk. In this study, the interaction of ßLG with three important nutrients, ascorbic acid (ASC), folic acid (FOL), and vitamin K3 (VK3) was investigated by spectroscopic methods (UV-visible and fluorescence) along with molecular docking technique. The results of fluorescence measurements showed that studied nutrients strongly quenched ßLG fluorescence in static (FOL and ACS) or static-dynamic combined quenching (VK3) mode. The values of binding constants (KßLG-ASC ~ 4.34 × 104 M-1, KßLG-FOL ~ 1.67 × 104 M-1and KßLG-VK3 ~ 13.49 × 104 M-1 at 310 K) suggested that VK3 and FOL had stronger binding affinity toward ßLG than ASC. Thermodynamic analysis indicated that hydrophobic interactions are the major forces in the stability of FOL-ßLG complex with enthalpy- and entropy-driving mode while, hydrogen bonds and van der Waals interactions play a major role for ßLG-ASC and ßLG-VK3 associations. The results of 3D fluorescence FT-IR and UV-Visible measurements indicated that the binding of above nutrients to ßLG may induce conformational and micro-environmental changes of protein. Also, there is a reciprocal complement between spectroscopic techniques and molecular docking modeling. The docking results indicate that the ASC, FOL, and VK3 bind to residues located in the subdomain B of ßLG. Finally, this report suggests that ßLG could be used as an effective carrier of above nutrients in functional foods.

Controllable synthesis and characterisation of palladium (II) anticancer complex-loaded colloidal gelatin nanoparticles as a novel sustained-release delivery system in cancer therapy.

Over the past few years, there have been several attempts to deliver anticancer drugs into the body. It has been shown that compared to other available carriers, colloidal gelatin nanoparticles (CGNPs) have distinct properties due to their exceptional physico-chemical and biological characteristics. In this study, a novel water-soluble palladium (II) anticancer complex was first synthesised, and then loaded into CGNPs. The CGNPs were synthesised through a two-step desolvation method with an average particle size of 378 nm. After confirming the stability of the drug in the nanoparticles, the drug-loaded CGNPs were tested for in vitro cytotoxicity against human breast cancer cells. The results showed that the average drug encapsulating efficiency and drug loading of CGNPs were 64 and 10 ± 2.1% (w/w), respectively. There was a slight shift to higher values of cumulative release, when the samples were tested in lower pH values. In addition, the in vitro cytotoxicity test indicated that the number of growing cells significantly decreased after 48 h in the presence of different concentrations of drug. The results also demonstrated that the released drug could bind to DNA by a static mechanism at low concentrations (0.57 µM) on the basis of hydrophobic and hydrogen binding interactions.

Assessment of the interaction procedure between Pt(IV) prodrug [Pt(5,5'-dmbpy)Cl4 and human serum albumin: Combination of spectroscopic and molecular modeling technique.

In this study, a cytotoxic Pt(IV) complex [Pt(5,5'-dmbpy)Cl4 (5,5'-dmbpy is 5,5'-dimethyl-2,2'-bipyridine) was selected to investigate its affinity to human serum albumin (HSA) by spectroscopy and molecular docking methods. This complex has a bidentate nitrogen donor ligand with four chloride anions attached to a Pt(IV) metal in a distorted octahedral environment. The fluorescence data showed this complex quench the intrinsic fluorescence of HSA through a static quenching mechanism. The binding constant (Kb) and the number of binding sites (n) were obtained based on the results of fluorescence measurements. UV-vis, circular dichroism spectroscopy, and three-dimensional fluorescence spectroscopy proved that the Pt(IV) complex could slightly change the secondary structure of protein. Thermodynamic parameters show that the Pt(IV) complex binds to HSA through electrostatic and Vander Waals interactions with one binding site. The molecular docking results confirmed the spectroscopic results and showed that Pt(IV) complex is embedded into subdomain IIA of protein. The aim of this study is to describe the performance of effective anti-cancer drugs when faced with proteins such as HSA.

Synthesis, spectral characterization, crystal structure and in vitro DNA/protein binding studies of phosphorous ylide palladacyclic complexes containing azide group.

The reaction between (4-nitrobenzoylmethylene)triphenylphosphorane Pd(II) complex [Pd{κ(2)(C,C)-C6 H4PPh2C(H)CO(C6 H4NO2-4)}(µ-Cl)]2 and excess of NaN3 resulted in the µ-N3 bridged Pd(II) complex [Pd{κ(2)(C,C)-C6H4PPh2C(H)CO(C6 H4NO2-4)}(µ-N3)]2 (1), which underwent bridge cleavage reactions with monodentate ligands to afford the monomeric, neutral complexes [Pd{κ(2)(C,C)-C6 H4PPh2C(H)CO(C6 H4NO2-4)}N3(L)] (L=Me3Py (1a), PPh3 (1b)). The complexes were identified and characterized by elemental analyses, infrared (IR), ((1))H, ((13))C{((1))H} and ((31))P{((1))H} NMR spectroscopy. The molecular structure of 1b was determined by single-crystal X-ray diffraction. The interactions of complexes with FS-DNA were investigated using UV absorption and fluorescence spectra. The results suggested that both complexes could interact with FS-DNA through the intercalation mode and follow the binding affinity order of 1a>1b. The reactivity toward protein BSA revealed that the quenching of BSA fluorescence by the two complexes are static quenching, and complex 1a exhibits a higher BSA-binding ability than the complex 1b.