Erlotinib-Modified BODIPY Photosensitizers for Targeted Photodynamic Therapy.

Photodynamic therapy (PDT) is an innovative, non-invasive and highly selective therapeutic modality for tumours and non-malignant diseases. BODIPY based molecules can function as new generation photosensitizers (PSs) in various PDT applications. Despite numerous conjugated PS systems are available, BODIPYs containing erlotinib lagged behind other photosensitizer units. In this study, smart photosensitizers containing BODIPY, erlotinib and hydrophilic units were prepared for the first time, their physicochemical properties and PDT effects were investigated. Compared with non-halogenated compound, halogenated derivatives possessed much lower fluorescence profile as well as the good ROS generation ability under red light. In vitro PDT studies were performed on both healthy (PNT1a) and prostate cancerous cells (PC3) to determine the selectivity of the compounds on cancerous cells and their effects under light. The halogenated conjugates, exposed to low dose of light illumination exhibited potent activity on cancer cell viability and the calculated IC50 values proved the high phototoxicity of the photosensitizers. It was also determined that the PSs have very low dark toxicity and that the light illumination and ROS formation are required for the initiation of the cell death mechanism. As a result, erlotinib modified BODIPYs could serve as promising agents in anticancer photodynamic therapy.

Azaindole-BODIPYs: Synthesis, fluorescent recognition of hydrogen sulfate anion and biological evaluation.

The synthesized and sensing capability of two novel azaindole substituted mono and distyryl BODIPY dyes against bisulfate anion were reported. Structural characterizations of the targeted compounds were conducted by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 1H and 13C NMR spectroscopies. Photophysical properties of the azaindole substituted BODIPY compounds were investigated employing absorption and fluorescence spectroscopies in acetonitrile solution. It was found that the final compounds 3 and 4 exhibited exclusively selective and sensitive turn-off sensor behavior on HSO4- anion. Additionally, the stoichiometry ratio of the targeted compounds to bisulfate anion was measured 0.5 by Job's method. Also, density function theory was performed to the optical response of the sensor for targeted compounds. Furthermore, the cytotoxicity of Azaindole-BODIPYs was examined against living human leukemia K562 cell lines.

Study on the Synthesis, Photophysical Properties and Singlet Oxygen Generation Behavior of Bodipy-Functionalized Cyclotriphosphazenes.

A new series of bodipy-functionalized cyclotriphosphazene derivatives were designed and synthesized. The identities of all newly synthesized compounds were confirmed by using 1H, 13C, 31P NMR spectroscopies. The photophysical properties of bodipy-functionalized cyclotriphosphazenes were investigated via absorption and fluorescense spectroscopies in dichloromethane. Singlet oxygen generation capacities of new compounds were also examined using the trap molecule 1,3-diphenylisobenzofuran. The targeted compounds showed high molar extinction coefficients in the NIR region and respectable singlet oxygen quantum yields when compared to that of methylene blue. The new bodipy-functionalized cyclotriphosphazenes are efficient photosensitizers to be potentially used for the singlet oxygen generation.

Octa-BODIPY derivative dendrimeric cyclotetraphosphazenes; photophysical properties and fluorescent chemosensor for Co2+ ions.

We have designed and synthesized the first examples of fluorescent chemosensors based on octa-BODIPY decorated dendrimeric cyclotetraphosphazenes. The structures these synthesized compounds were verified by 1H, 13C, 31P NMR spectroscopies and UV-vis electronic absorption spectra. The photophysical and metal sensing properties in THF solutions of dendrimeric cyclotetraphosphazenes (OBCP 1-3) were investigated by fluorescence spectroscopy. OBCP 1-3 showed strong absorption in the 500-640nm region with high molar extinction coefficients. Additionally, octa-BODIPY decorated dendrimeric cyclotetraphosphazenes are candidate for fluorescent chemosensor for Co2+ showing high selectivity with a low limit of detection.

Modular logic gates: cascading independent logic gates via metal ion signals.

Systematic cascading of molecular logic gates is an important issue to be addressed for advancing research in this field. We have demonstrated that photochemically triggered metal ion signals can be utilized towards that goal. Thus, independent logic gates were shown to work together while keeping their identity in more complex logic designs. Communication through the intermediacy of ion signals is clearly inspired from biological processes modulated by such signals, and implemented here with ion responsive molecules.

Stereo-selectivity in a cyclotriphosphazene derivative bearing an exocyclic P-O moiety.

Nucleophilic substitution reactions of N(3)P(3)Cl(4)[O(CH(2))(2)NCH(3)], (1) with the sodium salts of mono- and di-functional alcohols [methanol (2), phenol (3), tetraethyleneglycol (4) and 1,3-propanediol (5)] were carried out in order to investigate a possible directing effect of the spiro O-moiety on the formation of mono-substituted (2a, 3a), non-geminal di-substituted (2c, 3c) and ansa (4a, 5a) derivatives. Compounds isolated from the reactions were characterized by elemental analysis, mass spectrometry, (1)H and (31)P NMR spectroscopy and X-ray crystallographic analysis showed that the substituent OR in compounds (2a, 3a and 2c, 3c) and the ansa-ring in compounds (4a, 5a) formed cis to the P-O moiety of the exocyclic [O(CH(2))(2)NCH(3)] spiro ring. The formation of products (2a-d, 3a-d, 4a, 5a and 5b) was quantified from the (31)P NMR spectra of the reaction mixtures, which showed an overwhelming preference for derivatives (2a, 3a, 2c, 3c, 4a, 5a) with the substituent cis to the P-O moiety of the exocyclic spiro ring (2a, 3a, 2c, 3c, 4a, 5a), except for reaction with 1,3-propanediol where the six-membered ring spiro derivative (5b) was about three times more abundant than the eight-membered ring ansa-derivative (5a). Overwhelming formation of products with the substituent cis to the exocyclic P-O moiety is proof that the cation-assisted mechanism is responsible for the stereo-selectivity in the reactions with alkoxides.

Synthesis, cytotoxicity and apoptosis of cyclotriphosphazene compounds as anti-cancer agents.

In the present study, a number of new dispirobino and dispiroansa spermine derivatives of cyclotriphosphazene (8-10, 13) were synthesized and characterized by elemental analysis, mass spectrometry, (1)H and (31)P NMR spectroscopy. At first, in vitro cytotoxic activity of cyclotriphosphazene compounds (1-14) against HT-29 (human colon adenocarcinoma), Hep2 (Human epidermoid larynx carcinoma), and Vero (African green monkey kidney) cell lines was investigated. Our study showed that most of these compounds stimulate apoptosis and they have cytotoxic effects for HT-29 and Hep2 cells. Additionally, these compounds (1-14) were investigated for their antibacterial activity against gram-positive (Staphylococcus aureus), gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria and for their antifungal activity against Candida albicans, and were shown to be inactive.

Competitive formation of cis and trans derivatives in the nucleophilic substitution reactions of cyclophosphazenes having a mono-spiro P-NHR group.

Nucleophilic substitution reactions of N(3)P(3)Cl(4)[NH(CH(2))(3)NMe] (1) and N(3)P(3)Cl(4)[NH(CH(2))(3)O] (2) with mono-functional alcohols (methanol, 2,2,2-trifluoroethanol, phenol) and a secondary amine (pyrrolidine) were used to investigate the relationship between the incoming nucleophile and the proportions of products with substituents that are cis or trans to the spiro NH moiety. The reaction products were characterized by elemental analysis, mass spectrometry, (1)H and (31)P NMR spectroscopy and the configurational isomers by X-ray crystallography. Six products have been characterised with the substituent cis to the spiro NH group for the alcohol (methanol, phenol) and pyrrolidine derivatives of both compounds 1 and 2, compared to just one derivative with the substituent trans to the spiro NH group, that for the pyrrolidine derivative of compound 2. For each reaction the relative proportions of cis and trans isomers were determined by (31)P NMR measurements of the reaction mixtures. It was found that the reactions of compound 1 with all three alcohols and of compound 2 with methanol lead to exclusive formation of isomers with the substituent cis to the NH moiety, whereas all other reactions lead to mixtures of cis and trans isomers in different ratios under standard reaction conditions. However, when crown ether is included in the reaction medium for the reactions of compound 2 with both 2,2,2-trifluoroethanol and phenol, it is found that only cis isomers are formed. All these results are rationalised in terms of the competition between at least two effects; the cis-directing effect by hydrogen bonding of the incoming nucleophile to the spiro N-H group already present on the cyclophophazene ring and the cis-directing effect of the sodium cation coordinating to the oxygen lone pairs of the P-O moiety of the spiro ring.