Impact of Structural Subtleties on Chirality Induction and Amplification in Trizinc(II)Porphyrin Trimers.

Herein, we report the precise control of molecular to supramolecular chirality induction at the single-molecule level just upon subtle modification in an achiral 'nano-size' trizinc(II) porphyrin trimer. A slight variation in the projection of the substituent at the periphery of the central porphyrin unit in a porphyrin trimer (host) resulted in pronounced changes in the interchromophoric arrangement, leading to distinct 'open' and 'closed' conformations. While 'open' form generates 'monomeric' complex with low CD amplitude, 'closed' form produces exclusive 'polymer' with large, amplified CD signal with opposite sign due to stronger intermolecular excitonic coupling.

Conformational Switching of a Nano-Size Urea-Bridged Zn(II)Porphyrin Dimer by External Stimuli.

For the first time, explicit stabilization of all the three conformers, viz. (cis,cis), (cis,trans) and (trans,trans), of a 'nano-sized' highly-flexible urea-bridged Zn(II)porphyrin dimer have been achieved via careful manipulations of external stimuli such as solvent dielectrics, temperature, anionic interactions, axial ligation and surface-induced stabilization. The conformers differ widely in their structures, chemical and photophysical properties and thus have vast potential applicability.

Induction and rationalization of supramolecular chirality in a highly flexible Zn(II)porphyrin dimer: structural, spectroscopic and theoretical investigations.

A highly flexible pyrrole-bridged Zn(II)porphyrin dimer has been successfully utilized as an efficient host which enables an accurate determination of the absolute configuration directly for a large number of chiral amino alcohols and 1,2-diols. The addition of substrates resulted in the formation of 1 : 1 complexes which, after the addition of excess substrates, produced 1 : 2 host-guest complexes. In principle, the 1 : 2 host-guest complexes can be stabilized in three possible conformations, -, -, and - based on how a substrate binds to the metal.

Visible transparent white light emitting ink from a Ce sensitized monodispersed Tb,Sm co-doped LaF@C-dot nanocomposite.

Bright white light emission (CIE values 0.32 and 0.33) has been achieved by a single excitation source (254 nm) from a monodispersed nanocomposite composed of Ce3+, Tb3+ and Sm3+ doped LaF3 nanocrystals (NCs) and N-doped C-dots where Ce3+ acts as an excellent sensitizer.