Novel fluorescent probes for highly selective two-photon imaging of mitochondria in living cells

Efficient Excited‐State Symmetry Breaking in a Cationic Quadrupolar System Bearing Diphenylamino Donors

“…Figure 2(a) shows the absorption and emission spectra of compound 2 in comparison with those of compound 1 in both al ow-polarity (DCM) and ah igh-polarity( MeOH)s olvent. On the contrary,i ti sn oteworthy that in both solvents the emission bands of compounds 1 and 2 roughlyo verlap [ Figure 2(a)].T his peculiar behaviour was pre-viously found in highly polar media for similar dipolar and quadrupolarcompounds where the electron donor was adimethylamino group, [26] but it is here surprisingly observed in all the investigated solvents regardless of their polarity.W hen significantly strong electron donor groups are present in the quadrupolarD -p-A + -p-D structure (such as diphenylamino or also dimethylamino groups), that is, in systems showing as trongq uadrupolar character,t his surprising coincidence between the emission bands of dipolara nd quadrupolara nalogues is observed. Moreover,a se xpected for compounds where the two arms act as almost separatec hromophores, [39] the value of the extinction coefficient measured for 2 is almost twice the one obtained in the case of compound 1 (e 1 = 36 750 m À1 cm À1 and e 2 = 62 650 m À1 cm À1 in DCM).Abathochromic shift of the spectra of the two-arm system with respect to those of the one-arm chromophore would be expected also for the emission bands.…”

“…The absorption band undergoes asignificant blue shift and enlargement on going from low polar toward highly polar solvents (e.g. [26,30] The emission band, which is centred around6 80 nm in low polar solvents such as DCM and appearsr ather narrow in these media (e.g. Ac lear correlation of the absorption maximum position with solventp olarity can be seen when alkanec hloride and protic solvents are considered (see Ta ble 1), as reportedi nt he literaturef or other methylpyridinium derivatives.…”

“…[21,22] Interestingly,al arger 2PAr esponse was recently observed in quadrupolar D-p-A-p-D structuresw here two diphenylamines replacedt he analogous dimethylamino lateral groups. [25,26] In our recent work, [27] ac ationic D-p-A + -p-D quadrupolar system,w here am ethylpyridinium is the central electron acceptor and dimethylamino substituentsa re the laterale lectron We report aj oint experimental and theoretical investigation of aq uadrupolar D-p-A + -p-D system,t he electron donors being diphenylamino groups and the electron acceptor being am ethylpyridinium, in comparison with the dipolar D-p-A + system.T he emission spectra of the two compounds overlap in all the investigated solvents. For example, it was recently observed that the presence of ac ationic imidazolium in push-pulli odide salts replacingt he neutrali midazole acceptora llowedh igher2 PA cross sections to be observed because of the enhancede lectron acceptors trength of the positively chargedi midazole moiety.…”

Design and synthesis of fluorenone-based dyes: two-photon excited fluorescent probes for imaging of lysosomes and mitochondria in living cells

“…18 In addition, the 2PM uses low-energy near-infrared laser excitation and allows deep penetration with low photobleaching and photodamage of the tissue during the imaging. [19][20][21][22] This being so, a significant demand remains for lysosomes and mitochondria selective probes with high bio-and photo-stability, low cytotoxicity, large Stokes shift, and having long-wavelength emission peaks, in order to facilitate tissue penetration. [15][16][17] However, two-photon fluorescent probes for mitochondria are still rare.…”

A theoretical investigation of the two-photon absorption and fluorescent properties of coumarin-based derivatives for Pd2+ detection

“…1 14 So far, although there are some theoretical and experimental reports for TP uorescent probes, [22][23][24][25][26][27] there have been no theoretical research reports of TP probes based on Pd 2+ -triggered chemical catalytic reactions and coumarin derivatives, and the relationship between the molecular structure and nonlinear absorption properties of coumarin derivatives is still unclear. This study is devoted to providing some strategies for designing a series of novel TP molecules based on coumarin cores, shown in Fig.…”