Monophenylboryl aza-BODIPY with free rotation of the B-phenyl group for enhanced photothermal conversion.

Owing to the efficient non-radiative relaxation by the free rotation of the B-phenyl moiety, monophenyl substituted aza-BODIPY on the boron centre with near-infrared absorption has high photothermal conversion efficiency, which is highly desirable for a photothermal therapy agent.

Aza-BODIPY with two efficacious fragments for NIR light-driven photothermal therapy by triggering cancer cell apoptosis.

The reasonable structure of aza-BODIPY renders it as an efficient photothermal reagent for photothermal therapy. Herein, we describe the design and synthesis of aza-BODIPY NMeBu with the free rotating tert-butyl group and the dimethylamino-substituted segment to promote the photothermal conversion via the excited state non-radiative transition. NMeBu was found to be the π-π stacking form in the unit cell based on X-ray analysis. NMeBu-NPs by self-assembly possessed a near-infrared absorption (λabs = 772 nm), and once activated by near-infrared light, the photothermal efficiency in aqueous solution can reach 49.3%. NMeBu-NPs can penetrate the cell and trigger cell death via the apoptosis pathway under low concentration and low light power irradiation, thereby avoiding dark toxicity. Aza-BODIPY created using this procedure has excellent photothermal efficiency and could serve as a potential candidate for the treatment of cancer cells and tumors.

Attachment of -tBu groups to aza-BODIPY core at 3,5-sites with ultra-large Stokes shift to enhance photothermal therapy through apoptosis mechanism.

By the introduction of the -tBu groups into aza-BODIPY core, di-tert-butyl-substituted aza-BODIPYs at 3,5-sites (tBuazaBDPs) were prepared for the first time. Based on the X-ray analysis of CN-tBuazaBDP, this molecular structure is twisted. Near-infrared dye SMe-tBuazaBDP has the ultra-large Stokes shift (152 â€‹nm) in aza-BODIPY system, combining with the twisted intramolecular charge transfer and the free rotation of the -tBu groups at 3,5-sites. Although the barrier-free rotors of the distal -tBu groups in SMe-tBuazaBDP result in low fluorescence quantum yield, the photothermal conversion efficiency is markedly enhanced. SMe-tBuazaBDP nanoparticles with low power laser irradiation were proven to block cancer cell cycle, inhibit cancer cell proliferation, and induce cancer cell apoptosis in photothermal therapy (PTT). The strategy of "direct attachment of -tBu groups to aza-BODIPY core" gives a new design platform for a photothermal therapy agent.

Synthesis of aza-BODIPYs with barrier-free rotation of the -tBu group at 3-site and enhancement of photothermal therapy by triggering cancer cell apoptosis.

Breaking through the traditional 1,7,3,5-aryl substituted aza-BODIPY structure, asymmetric aza-BODIPYs, tBu-azaBDPs, containing non-aryl group at 3-site were prepared for the first time. tBu-azaBDP exhibited a severely twisted configuration. tBu-azaBDPs had a near-infrared fluorescence emission and high molar extinction coefficients. Although the barrier-free rotation of the distal -tBu group in tBu-azaBDP resulted in low fluorescence quantum yield, the photothermal conversion efficiency was markedly enhanced. tBu-azaBDP nanoparticles with laser irradiation were revealed to induce cell apoptosis in photothermal therapy. We consider that development of aza-BODIPYs with the barrier-free rotation of the -tBu group at 3-site provides a strong platform for design of phototherapy agents for cancer treatment in photothermal therapy by apoptosis.

Near-infrared upper phenyl-fused BODIPY as a photosensitizer for photothermal-photodynamic therapy.

The introduction of a ring-fused segment into a BODIPY scaffold promoted a spectral bathochromic-shift and enhanced the intersystem crossing capability by a twisted structure. In this work, we designed and synthesized an upper ring-fused BODIPY with 4-dimethylaminostyryl groups (BBDP), which had excellent optical performance for photothermal-photodynamic therapy.

1,7-Di-tert-butyl-Substituted aza-BODIPYs by Low-Barrier Rotation to Enhance a Photothermal-Photodynamic Effect.

1,7-Di-tert-butyl-substituted aza-BODIPYs (tBu-azaBDP) were successfully obtained for the first time. The structures of tBu-azaBDP and Ph-azaBDP were confirmed by X-ray crystal analysis, and tBu-azaBDP 2 is more twisted than Ph-azaBDP 5. tBu-azaBDPs have significant photo-stability and enhanced water solubility. tBu-azaBDPs possess excellent optical properties, such as high molar extinction coefficients, broad full width half maxima, and large Stokes shifts, which is comparable to those of the parent dye Ph-azaBDP. Although the low-barrier rotation of the distal -tBu groups in tBu-azaBDPs results in low quantum yield, photothermal conversion efficiency and singlet oxygen generation ability of tBu-azaBDPs are more effective than those of Ph-azaBDP, which is highly desirable for a photothermal-photodynamic therapy agent.

Synthesis and characterization of a pair of O-fac/O-mer 12-P-6 alkyloxaphosphates with a P-O-C-C four-membered ring.

Structurally characterized hexacoordinate organophosphorus compounds remain rare due to their highly reactive nature and thermal instability. Herein we report the first synthesis of a pair of O-facial and O-meridional hexacoordinate oxaphosphates (5B and 5D) obtained from the O-apical and O-equatorial ß-hydroxyalkylphosphoranes 3 and 4. This was achieved by using the bulky C2F5-groups on the ortho-substituted aryl backbone. Calculations of the relative energies of possible isomers indicate 5B and 5D are thermodynamic products. Although the mechanisms of their formation and the determining factor of stereo-selectivity are still unclear, their isolation and structure conformation contributes to a formulation of a viable strategy for diastereoselective synthesis of heteroleptic hexacoordinate organophosphates.

Flightless-I Blocks p62-Mediated Recognition of LC3 to Impede Selective Autophagy and Promote Breast Cancer Progression.

p62 is a receptor that facilitates selective autophagy by interacting simultaneously with cargoes and LC3 protein on the autophagosome to maintain cellular homeostasis. However, the regulatory mechanism(s) behind this process and its association with breast cancer remain to be elucidated. Here, we report that Flightless-I (FliI), a novel p62-interacting protein, promotes breast cancer progression by impeding selective autophagy. FliI was highly expressed in clinical breast cancer samples, and heterozygous deletion of FliI retarded the development of mammary tumors in PyVT mice. FliI induced p62-recruited cargoes into Triton X-100 insoluble fractions (TI) to form aggregates, thereby blocking p62 recognition of LC3 and hindering p62-dependent selective autophagy. This function of Flil was reinforced by Akt-mediated phosphorylation at Ser436 and inhibited by phosphorylation of Ulk1 at Ser64. Obstruction of autophagic clearance of p62-recruited cargoes by FliI was associated with the accumulation of oxidative damage on proteins and DNA, which could contribute to the development of cancer. Heterozygous knockout of FliI facilitated selectively autophagic clearance of aggregates, abatement of ROS levels, and protein oxidative damage, ultimately retarding mammary cancer progression. In clinical breast cancer samples, Akt-mediated phosphorylation of FliI at Ser436 negatively correlated with long-term prognosis, while Ulk1-induced FliI phosphorylation at Ser64 positively correlated with clinical outcome. Together, this work demonstrates that FliI functions as a checkpoint protein for selective autophagy in the crosstalk between FliI and p62-recruited cargoes, and its phosphorylation may serve as a prognostic marker for breast cancer.Significance: Flightless-I functions as a checkpoint protein for selective autophagy by interacting with p62 to block its recognition of LC3, leading to tumorigenesis in breast cancer.Cancer Res; 78(17); 4853-64. ©2018 AACR.

Effect of CaCN2 on the preparation of CaAlSiN3 :Eu2+ phosphors.

Highly efficient red-emitting phosphors, CaAlSiN3 :Eu2+ , were successfully prepared by the solid-state method using calcium cyanide (CaCN2 ) as the single calcium source. The influences of crystallization temperature, crystallization time, calcination mode and compounds ratio on the photoluminescent properties were investigated. The CaAlSiN3 :Eu2+ phosphors were obtained with 1 mol% CaCN2 by a two-step calcination procedure at 900°C for 2 h and subsequently at 1600°C for 8 h. The CaAlSiN3 :Eu2+ phosphors showed the strongest luminescent intensity at 660 nm when excited by 468 nm. With an increase in crystallization time, the maximum wavelength of the emission was shifted from 644 nm to 660 nm.

Singlet oxygen generation properties of isometrically dibromated thienyl-containing aza-BODIPYs.

Isometrically dibromated thienyl-containing aza-BODIPYs CDB-1 and BDB-2 with potential use as photosensitizers (PSs) were successfully prepared and their photophysical properties were fully characterized. Singlet oxygen generation experiments were also performed. In this regard, PS CDB-1 was found to be more effective and had about two-fold rate enhancement compared to PS BDB-2. DFT and TD-DFT calculations helped to provide insights into the distinct intersystem crossing (ISC) processes observed for CDB-1 and BDB-2.

A new water-soluble phosphorus-dipyrromethene and phosphorus-azadipyrromethene dye: PODIPY/aza-PODIPY.

PODIPY and aza-PODIPY have been successfully prepared by the treatment of dipyrromethene and azadipyrromethene with POCl3 in the presence of Et3 N. The new PODIPY and aza-PODIPY dyes are found to have photophysical properties. PODIPY and aza-PODIPY are water-soluble, and aza-PODIPY is suited for labeling living Hep-2 cells for imaging assays in the near-infrared region. Molecular orbital calculations show that the increase in the HOMO-LUMO band gap for the lowest energy absorption bands is observed in the new phosphorus-containing aza-PODIPY, and the HOMO and LUMO energies of aza-PODIPY are found to be higher than those of aza-BODIPY.

Synthesis and characterization of antiapicophilic arsoranes and related compounds.

Utilizing bulky bidentate ligand systems with C(2)F(5) and n-C(3)F(7) groups, antiapicophilic arsoranes (5b and 5c, respectively) were synthesized. A kinetic study on the isomerization of these arsoranes to their more stable isomers showed that the barriers increased in the order of CF(3) < C(2)F(5) < n-C(3)F(7) in accord with their steric bulk. It was also revealed that the degree of freezing isomerization was larger for the change from CF(3) to C(2)F(5) than from C(2)F(5) to n-C(3)F(7), obvious from the differences in activation free energy at 363 K of 1.6 and 0.3 kcal mol(-1), respectively. X-ray structural analysis of several precursors of these two systems disclosed the unique structures of these compounds.

A NIR BODIPY dye bearing 3,4,4a-trihydroxanthene moieties.

A novel 3,4,4a-trihydroxanthene-fused pyrrole 2 was synthesized by the reaction of 2,3,4,4a-tetrahydro-1H-xanthen-1-one with 3-phenyl-2H-azirine in the presence of LDA. Utilizing this pyrrole 2, a NIR BODIPY 1 (λ(abs) = 732 nm, λ(em) = 747 nm) has been prepared. The new BODIPY 1 was stable, non-cytotoxic, and suited to labeling living cells for imaging assay in the NIR region.

A selective fluorescent turn-on NIR probe for cysteine.

A selective and sensitive turn-on fluorescent NIR probe for cysteine has been developed. Cleavage of 2,4-dinitrobenzenesulfonyl (DNBS) with thiols switches the weakly fluorescent aza-BODIPY dye (λ(em) = 734 nm, Φ(f) = 0.03) to a strongly fluorescent species in the NIR region (λ(em) = 755 nm, Φ(f) = 0.14).

Development of mono- and di-AcO substituted BODIPYs on the boron center.

Mono- and di-AcO substituted BODIPYs (1 and 2) were synthesized from TM-BDP. The structures of 1 and 2 were supported by single crystal X-ray analysis. Both 1 and 2 possess a large absorption coefficient, high fluorescence quantum yield, and high light stability. Compound 2 has much improved water solubility which is highly desirable for biological applications. Theoretical calculation supports our observations in X-ray analysis, absorption, and cyclic voltammetry.

Efficient synthesis of tetradecafluoro-4-phenylheptan-4-ol by a Cannizzaro-type reaction and application of the alcohol as a bulky Martin ligand variant for a new anti-apicophilic phosphorane.

Alcohols 8 bearing two identical perfluoroalkyl groups were prepared by the reaction of the corresponding perfluoroalkyl phenyl ketones 7 with 0.5 equivalents of t-BuOK via Cannizzaro-type disproportionation. Utilizing the new bulky bidentate ligand with two n-C(3)F(7) groups generated from 8c, anti-apicophilic phosphorane 5a and its stable isomer 6a were synthesized. The crystal structures of 5a and 6a were slightly affected by the steric repulsion of heptafluoropropyl groups. Kinetic studies on the isomerization of 5a to 6a showed that the new ligand was effective for decreasing the isomerization rate compared with its C(2)F(5) analog 3a to about half.

Synthesis, structure and isomerization of arylphosphoranes with anti-apicophilic bonding modes using a novel bidentate ligand with two C(2)F(5) groups.

A series of anti-apicophilic pentacoordinate phosphoranes (with one chelating substituent in an O-equatorial, C-apical bonding mode at pentacoordinated phosphorus atom) bearing a para-substituted aryl group (-C(6)H(4)(p-X); X = H, CF(3), F, OMe) or a mesityl (2,4,6-trimethylphenyl) group were isolated using a novel bulky bidentate ligand with two C(2)F(5) groups. These phosphoranes were stable to isomerization at room temperature, and quantitatively converted into the corresponding more stable isomers (O-apical) at elevated temperatures in solution. On the basis of a kinetic study, the free energy of activation (DeltaG(double dagger)) of the stereomutation of the O-equatorial mesitylphosphorane to its O-apical isomer was higher than that of the CF(3) derivative by 2.6 kcal mol(-1), giving rise to a further example of the steric effect of the C(2)F(5) group to freeze the isomerization of the pentacoordinate phosphorus compounds. Kinetic measurements of the isomerization of the O-equatorial ortho-unsubstituted derivatives (-C(6)H(4)(p-X)) to the corresponding O-apical isomers suggested that the O-equatorial isomers were stabilized by the pi --> sigma*(P-O) interaction in the ground state.

Diaqua-bis[3-(2-hydroxy-ethyl)-2-methyl-4-oxopyrido[1,2-a]pyrimidin-9-olato-κN,O]manganese(II).

The title compound, [Mn(C(11)H(11)N(2)O(3))(2)(H(2)O)(2)], consists of discrete mononuclear complex mol-ecules. The Mn(II) atom is located on an inversion center and coordinated by two N atoms and two O atoms, each pair in a trans mode, from two 3-(2-hydroxy-ethyl)-2-methyl-4-oxopyrido[1,2-a]pyrimidin-9-olate ligands and by two water mol-ecules. The coordination geometry around the Mn(II) atom is slightly distorted octa-hedral. Mol-ecules are linked by O-H⋯O hydrogen bonds into a three-dimensional network.

Poly[(µ(6)-benzene-1,2,4,5-tetra-carboxyl-ato)bis-(1,10-phenanthroline-κN,N')dimanganese(II)].

The title polymeric compound, [Mn(2)(C(10)H(2)O(8))(C(12)H(8)N(2))(2)](n), was obtained by the reaction of manganese(II) chloride tetra-hydrate with benzene-1,2,4,5-tetra-carboxylic acid (H(4)bta) in aqueous solution. Each Mn(2+) ion is coordinated in a distorted octa-hedral geometry by two N atoms from one 1,10-phenanthroline ligand and four O atoms [Mn-O = 2.116 (2)-2.237 (2) Å] from three bta(4-) ligands, which also act as bridging groups between the Mn(2+) ions.

First isolation and kinetic study of hypervalent 10-As-5 organoarsenic compounds with a C-apical, O-equatorial configuration.

Hypervalent organoarsenic compounds violating the apicophilicity concept were isolated for the first time, and the energy of isomerization of these arsoranes to the more stable stereoisomers appeared to be lower than that of the phosphorus analogues based on the kinetic studies.