Synthese De Quelques Spiro[Indoline-Naphtoxazines] Et Spiro[Indoline-Pyridobenzoxazines] Photochromiques. Application De La Methodologie De La Recherche Experimentale

Design of Collective Motions from Synthetic Molecular Switches, Rotors, and Motors

Precise control over molecular movement is of fundamental and practical importance in physics, biology, and chemistry. At nanoscale, the peculiar functioning principles and the synthesis of individual molecular actuators and machines has been the subject of intense investigations and debates over the past 60 years. In this review, we focus on the design of collective motions that are achieved by integrating, in space and time, several or many of these individual mechanical units together. In particular, we provide an in-depth look at the intermolecular couplings used to physically connect a number of artificial mechanically active molecular units such as photochromic molecular switches, nanomachines based on mechanical bonds, molecular rotors, and light-powered rotary motors. We highlight the various functioning principles that can lead to their collective motion at various length scales. We also emphasize how their synchronized, or desynchronized, mechanical behavior can lead to emerging functional properties and to their implementation into new active devices and materials.

Subtle structural changes in octupolar merocyanine dyes influence the photosensitized production of singlet oxygen

The photophysical properties of two indoline-based octupolar merocyanine dyes and of the corresponding quinoline-based dyes were examined. This seemingly subtle structural change in the chromophore of these molecules has an appreciable effect on the yields with which these respective compounds sensitize the production of singlet molecular oxygen, O2(a(1)Δg). The indoline-based dyes are reasonably efficient O2(a(1)Δg) sensitizers (ϕΔ ∼ 0.35), whereas the quinoline-based dyes are poor O2(a(1)Δg) sensitizers (ϕΔ ∼ 0.005). A series of experiments, including Laser-Induced Optoacoustic Calorimetric (LIOAC) measurements, reveal that this difference principally reflects the fact that the excited singlet state of the quinoline-based dyes rapidly and efficiently decays via nonradiative channels to regenerate the ground state molecule. It is likely that a charge-transfer state mediates this efficient coupling between the excited and ground states. Such subtle, structure-dependent effects are important in elucidating and ultimately understanding phenomena that influence the efficiency of photosensitized O2(a(1)Δg) production. In turn, the knowledge gained facilitates the rational design and preparation of O2(a(1)Δg) sensitizers with explicitly controlled properties.

Synthesis and spectroscopic characterization of red-shifted spironaphthoxazine based optical switch probes

Spironaphthoxazine (NISO) is an efficient optical switch probe that has applications in high contrast detection of Foerster resonance energy transfer (FRET) using optical lock-in detection (OLID). NISO exists in two distinct states spiro (SP) and merocyanine (MC) that can be independently controlled by using alternate irradiation with near ultraviolet and visible light. Unfortunately, the SP-state of NISO has an absorption centered at 350 nm, which may lead to phototoxic effects when manipulating the probe within a living cell. To overcome this problem we introduce new, red-shifted amino substituted NISO probes compared to NISO that undergo an efficient SP to MC transition in response to irradiation by using 405-nm light, which is less damaging to living cells. This study details the synthesis of amino-substituted NISO and their N-hydroxysuccinimide ester and maleimide derivatives and their use in generating covalent attached protein conjugates. This study also presents a characterization of the spectroscopic and optical switching properties of these red-shifted NISO probe in solution.

The reaction of spiro[indoline-naphthopyrans] with nitrogen oxides. Not a case of biradical double trapping

The reactions of six differently substituted photochromic spiro[indoline-naphtopyrans] with .NO or .NO(2) under normal daylight conditions have been investigated by means of EPR spectroscopy along with those of three structurally related spiro[indoline-benzopyrans]. The spectra due to cyclic oxynitroxides originating from double trapping of biradicals by .NO were observed with the three latter derivatives, this finding being in agreement with previous results. Similar signals were also observed with the six former compounds, but in this case they were responsible for just a minor component of the spectra, the main spectral signals being due to hitherto unreported paramagnetic species that on the basis of their spectral parameters are identified as iminoxy radicals. DFT calculations at the B3LYP/6-31G* level carried out on a variety of radicals support this assignment.

Spirobipyridopyrans, spirobinaphthopyrans, indolinospiropyridopyrans, indolinospironaphthopyrans and indolinospironaphtho-1,4-oxazines: synthesis, study of X-ray crystal structure, antitumoral and antiviral evaluation

The novel racemic indolinospirobenzopyrans (5-7), indolinospironaphthopyrans (11-14) and indolinospironaphtho-1,4-oxazine (17) were synthesized by an aldol type of condensation of 1',3',3'-trimethyl-2 '-methyleneindoline and its 5-substituted derivatives with an appropriately substituted hydroxybenzaldehyde, hydroxynaphthaldehyde or nitrosonaphthol. An unequivocal proof of the stereostructures of 9 and 17 was obtained by the single-crystal X-ray diffraction method. A substituted indoline ring and the benzopyran ring in 9 and the naphtho-1,4-oxazine moiety in 17 are interconnected via the common chiral atom and positioned almost perpendicularly to each other. The five-membered 2,3-dihydropyrrolo moiety of the indoline ring adopts an envelope conformation in both structures. Of all the compounds of this series, spirobipyridopyran (1) inhibited specifically the growth of human melanoma (HBL) (IC(50): 0.9 microM) cells but not the growth of normal fibroblasts (WI38). Indolinospirobenzopyrans (8-10) showed significant cytostatic activities against all tumor cell lines. However, these compounds also exhibited a cytotoxic effect on normal human fibroblasts. The indolinospirobenzopyrans 4, 6-8, 10 and the indolinospironaphtho-1,4-oxazine 16 showed, albeit modest, selectivity as antiviral agents against varicella-zoster virus (VZV) and/or cytomegalovirus (CMV) (EC(50) within the concentration range of 1.0-12.6 microM).