25 research outputs found
Recommended from our members
Synthesis of (E)-nitroolefins via decarboxylative nitration using t-butylnitrite (t-BuONO) and TEMPO.
Nitroolefins are usually synthesized using the Henry reaction. Here we report an alternative metal-free decarboxylative nitration protocol for the preparation of the nitroolefins from Ī±,Ī²-unsaturated carboxylic acids using t-butylnitrite (t-BuONO) and TEMPO. Ī±,Ī²-Unsaturated carboxylic acids bearing Ī²-aromatic and Ī²-heteroaromatic substituents gave (E)-nitroolefins exclusively under mild conditions. A radical based pathway has been proposed for this decarboxylative nitration reaction
Pure white light emission and charge transfer in organogels of symmetrical and unsymmetrical π-chromophoric oligo-p-(phenyleneethynylene) bola-amphiphiles
Two novel bola-amphiphilic oligo-p-(phenyleneethynylene) (OPE) dicarboxylates have been synthesized having non-polar and mixed-polar side chains. This led to gelation in both with vesicular morphology. Upon in situ loading of a suitable dye and redox-active molecule, pure white light emitting and charge transfer (CT)-gels, respectively, were realized
Three photon absorbing photocatalyst enabled defluorinative amination of fluoroarenes
We have developed a photocatalytic system that explores the latent potential of a new photocatalyst HATCN. The architecture of this flat molecule is well poised to pose it as a great photooxidant, that can also afford multiple redox states. The excited reduction potential of HATCN is calculated as 2.83 V which corroborates well with its strong oxidizing behavior. A large number of SNAr reactions have been conducted over a wide variety of fluororenes with varying electronic nature. The catalytic efficiency of the photocatalyst has been demonstrated by successful reaction to both electron-neutral and -poor fluoroarenes. Furthermore, the great utility of this developed protocol has been established by applying this method over a large number of building blocks of drugs and pharmaceutically important moieties. An extensive studies delineate the involvement of three photons for one catalytic cycle, that is unprecedented in photocatalysis. Furthermore, the redox modularity of the photocatalyst gives access to the oxidant and reductant behavior of the same molecule at different stages of the catalytic cycle. This discovery of novel mechanistic paradigm will translate in solving challenging photochemical processes
GuestāResponsive Reversible Electron Transfer in a Crystalline Porous Framework Supported by a Dynamic Building Node
Nanovesicular MOF with Omniphilic Porosity: Bimodal Functionality for White-Light Emission and Photocatalysis by Dye Encapsulation
A new
Ļ-chromophoric and asymmetric bola-amphiphilic oligo-(<i>p</i>-phenylene ethynylene)-based tetracarboxylate (<b>OPE-TC1</b>) linker was designed, synthesized, and self-assembled with ZnĀ(OAc)<sub>2</sub>. The resulting nanoscale metalāorganic framework (MOF)
{Zn<sub>2</sub>(<b>OPE-TC1</b>)}<i><sub>n</sub></i> (<b>NMOF-1</b>) showed a vesicular morphology and permanent
porosity with omniphilic pore surface. <b>NMOF-1</b> showed
cyan emission with high quantum efficiency (49%). The omniphilicity
of the pore was utilized to incorporate ambipolar dye sulforhodamine
G (<b>SRG</b>) to tune the band gap as well as to get pure white-light
emission. Furthermore, the polar pore surface of <b>NMOF-1</b> allowed facile diffusion of the substrate for efficient photocatalytic
activity. The dye-encapsulated framework further showed enhanced dihydrogen
production by 1.75-fold compared to that from the as-synthesized <b>NMOF-1</b> because of the modulated band gap and high excited
state lifetime. As a control experiment, we have synthesized a MOF
(<b>MOF-OMe</b>) with an <b>OPE-TC2</b> linker having
āOMe functional groups that did not show nanoscale architecture.
This suggested the important role of unsymmetrical bola-amphiphilicity
in nanostructuring. This rational design of a chromophoric linker
resulted in a nanoscale MOF with omniphilic porosity to achieve bimodal
functionality in clean energy applications
Excitation Energy Transfer Supported Amplified Charge-Transfer Emission in an Anthracenedicarboxylate- and Bipyridophenazine-Based Coordination Complex
A highly luminescent
tetrameric zincĀ(II) complex, {[Zn<sub>4</sub>(adc)<sub>3</sub>(bpz)<sub>6</sub>(HCOO)<sub>2</sub>]Ā·2H<sub>2</sub>O} (<b>1</b>;
adc = 9,10-anthracenedicarboxylate and bpz = bipyridophenazine), was
synthesized by a solvothermal technique and characterized by single-crystal
X-ray diffraction. The linear tetrameric units extend into three dimensions
via Ļ stacking of adc/bpz and bpz/bpz and multiple CHāĻ
interactions. The compound shows strong red emission at 597 nm (Ī»<sub>ex</sub> = 480 nm), which is attributed to charge-transfer (CT) emission
within an adc/bpz donorāacceptor pair. This is also supported
by density functional theory computations. Interestingly, the CT emission
is amplified by energy transfer from another adc linker that is not
involved in the CT interaction