Susnata Pramanik
@dartmouth.edu
Postdoctoral Fellow
LMU Munich, Dartmouth College
RESEARCH INTERESTS
Supramolecular chemistry. molecular switch, organic synthesis, molecular sensor
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Heyifei Fu, Susnata Pramanik, and Ivan Aprahamian
American Chemical Society (ACS)
Transition metals play an important role in many biological processes including cellular regulation and signal transduction. Emulating such processes on the molecular level, while challenging, can help us learn how to manipulate intermolecular communication, an important requirement for the development of solution-based molecular machines. In this work, we demonstrate a transition metal-based artificial multistep switching cascade that exhibits intrinsic hierarchical level control. The process starts with Zn(II), which initiates a transition metal relay by displacing a macrocycle-encapsulated Pd(II). The latter then binds to a hydrazone switch leading to coordination-coupled deprotonation (CCD). Finally, the proton generated through CCD activates the E/Z isomerization of a second noncoordinating pH-sensitive hydrazone switch. This whole multistep process can be reset to the original state by removing the Pd(II) from the system.
Naveen Kumar M, Deikrisha Lyngdoh Lyngkhoi, Sudhakar Gaikwad, Debabrata Samanta, Snehadrinarayan Khatua, and Susnata Pramanik
Royal Society of Chemistry (RSC)
One-step synthesis of six hydrazone derivatives exhibiting red-shifted absorption is reported. The compounds are red-emissive in their solid state with moderate to high quantum efficiency and show AIE properties, supported by DLS and SEM studies.
Rafiq Ahamed, Jayashree Venkatesh, Rakshantha Srithar, Sudhakar Gaikwad, and Susnata Pramanik
Royal Society of Chemistry (RSC)
This review summarises the recognition of carbohydrates using metal-ligand assemblies, including metallosupramolecules, macrocycles, and cages. It also highlights the challenges and future directions in the field.
Naveen Kumar M, Deikrisha Lyngdoh Lyngkhoi, Sudhakar Gaikwad, Jayanta Samanta, Rafiq Ahamed, Snehadrinarayan Khatua, and Susnata Pramanik
Royal Society of Chemistry (RSC)
Multi-coloured and white-light emissions from pyrene-based hydrazones are described.
Myeongsu Jeong, Jiyoon Park, Yejin Seo, Kwonjung Lee, Susnata Pramanik, Sangdoo Ahn, and Sunbum Kwon
Wiley
Molecules that undergo light-driven structural transformations constitute the core components in photoswitchable molecular systems and materials. Among various families of photoswitches, photochromic hydrazones have recently emerged as a novel class of photoswitches with superb properties, such as high photochemical conversion, spectral tunability, thermal stability, and fatigue resistance. Hydrazone photoswitches have been adopted in various adaptive materials at different length scales, however, their utilization for modulating biomolecules still has not been explored. Herein we present new hydrazone switches that can photomodulate the structures of short peptides. Systematic investigation on a set of hydrazone derivatives revealed that installation of the amide group does not significantly alter the photoswitching behaviors. Importantly, a hydrazone switch comprising an upper phenyl ring and a lower quinolinyl ring was effective for structural control of peptides. We anticipate that this work, as a new milestone in the research of hydrazone switches, will open a new avenue for structural and functional control of biomolecules.
Susnata Pramanik, Brice Kauffmann, Stefan Hecht, Yann Ferrand, and Ivan Huc
Royal Society of Chemistry (RSC)
A chiral guest induces opposite helix handedness in the two states of a photoswitchable host.
Nikita Mittal, Indrajit Paul, Susnata Pramanik, and Michael Schmittel
Informa UK Limited
ABSTRACT A multi-component system is presented in which the actuation of a copper-loaded nanoswitch by zinc(II) ions as an external trigger and the thereby prompted release of copper(I) ions allows self-assembly of 11 parts resulting in the formation of a three-component supramolecular prism. Using the same protocol, a three-component rectangle was made from eight parts. Disassembly of the aggregates was accomplished by selective removal of zinc(II) ions using hexacyclen. In sum, the reversible assembly and disassembly of supramolecular aggregates was controlled in a multi-component mixture through intermolecular communication using a second messenger. Graphical_abstract
Sudhakar Gaikwad, Merve Sinem Özer, Susnata Pramanik, and Michael Schmittel
Royal Society of Chemistry (RSC)
Entangled toggling leads to a rare case of a double-pole change-over switching. Since two connections are cleaved in a correlated manner, it represents an intriguing modus operandi of molecular nanoswitching.
Abir Goswami, Susnata Pramanik, and Michael Schmittel
Royal Society of Chemistry (RSC)
As an example of advanced molecular cybernetics eight components work together through chemical signaling reversibly setting up multifunctional nanomachinery.
Sudhakar Gaikwad, Susnata Pramanik, Soumen De, and Michael Schmittel
Royal Society of Chemistry (RSC)
Copper(i) ion translocation is the key for fast and reliable communication between networked devices in the catalytic machinery.
Hai Qian, Susnata Pramanik, and Ivan Aprahamian
American Chemical Society (ACS)
A family of easily accessible light-activated hydrazone switches has been developed having thermal half-lives of up to 2700 years! Structure-property analysis shows that replacing the rotor pyridyl group of our typical hydrazone switch with a phenyl one leads to the long-lived negative photochromic compounds. The switching properties of the hydrazones in both toluene and DMSO were assessed offering insights into the kinetics and thermodynamics of the switching process.
Nikita Mittal, Susnata Pramanik, Indrajit Paul, Soumen De, and Michael Schmittel
American Chemical Society (ACS)
The nanoswitches 1 and 2 are interdependently linked in so-called network states (NetStates). In NetState I, defined by presence of [Cu(1)]+ and 2, the organocatalyst N-methylpyrrolidine catalyzes a conjugate addition. Addition of iron(II) ions as an external chemical trigger to NetState I discharges Cu+ from [Cu(1)]+. The liberated copper(I) ion acts as a second messenger and changes the toggling state at nanoswitch 2. The resulting nanoswitch [Cu(2)]+ captures the catalytically active species from solution and the conjugate addition is turned OFF. Removal of the original trigger reverses the sequence and turns catalysis ON. The ON/OFF catalytic cycle was run three times in situ.
Susnata Pramanik and Ivan Aprahamian
American Chemical Society (ACS)
A negative feedback loop that relies on the coordination-coupled deprotonation (CCD) of a hydrazone switch has been developed. Above a particular threshold of zinc(II), CCD releases enough protons to the environment to trigger a cascade of reactions that yield an imine. This imine sequesters the excess of zinc(II) from the hydrazone switch, hence lowering the effective amount of protons, and switching the cascade reactions "OFF", thus establishing the negative feedback loop.
Michael Schmittel, Soumen De, and Susnata Pramanik
Royal Society of Chemistry (RSC)
The pyridine–pyrimidine (py–pym) arm as the moving part of the two-state nanomechanical rotary switch [Cu(1)]+ is toggled reversibly between two stations using one-electron oxidation/reduction.
Soumen De, Susnata Pramanik, and Michael Schmittel
Wiley
Reversible switching between two states of the triangular nanoswitch [Cu(1)](+) was accomplished by alternate addition of 2-ferrocenyl-1,10-phenanthroline (2) and copper(I) ions. The two switching states regulate the binding and release of two distinct catalysts, piperidine and [Cu(2)](+), in a fully interference-free manner and allow alternating on/off switching of two orthogonal catalytic processes. In switching state I, piperidine is released from the nanoswitch and catalyzes a Knoevenagel addition between 4-nitrobenzaldehyde and diethyl malonate (ON-1 and OFF-2), while in state II the released [Cu(2)](+) catalyzes a click reaction between 4-nitrophenylacetylene and benzylazide (OFF-1 and ON-2). Upon addition of one equivalent of 2 to the (OFF-1 and ON-2)-state, both catalytically active processes are shut down (OFF-1 and OFF-2).
Susnata Pramanik, Soumen De, and Michael Schmittel
Royal Society of Chemistry (RSC)
A potential-controlled two-step bidirectional communication protocol between the nanoswitches [Cu(1)](+), 2 and 3 is set up, in which ligand followed by metal-ion oxidation drives two subsequent metal ion translocations (self-sorting) changing the switching state at each switch. The communication is reset to its starting point by a two-electron reduction.
Soumen De, Susnata Pramanik, and Michael Schmittel
Royal Society of Chemistry (RSC)
A triangular framework with a terpyridine and shielded phenanthroline at its termini constitutes an open/close nanoswitch that is toggled by chemical inputs. In the presence of copper(I) ions, the open triangular framework (OPEN-I) firmly closes to a catalytically inactive heteroleptic [Cu(phen)(terpy)](+) complex (CLOSE). Reversible switching between CLOSE and OPEN-I states was demonstrated by successive addition and removal of Cu(+). In contrast, after addition of iron(II) ions to the CLOSE state a bishomoleptic dimeric [Fe(terpy)2](2+) complex is formed with the copper(I) ions placed in the phenanthroline cavities (OPEN-II). Due to its coordinatively unsaturated [Cu(Phen)](+) sites the dimeric iron complex is able to serve as a catalyst in the cyclopropanation of Z-cyclooctene using ethyl diazoacetate.
Susnata Pramanik, Soumen De, and Michael Schmittel
Wiley
The interplay of biological machines depends critically on the bidirectionality of chemical information exchange. The implementation of such a communication procedure for abiological systems is achieved using two nanoswitches that both operate as transmitters and receivers by transfering copper ions in oxidation states +I and +II. Even at micromolar concentrations, communication in both directions is remarkably fast, occurring at t1/2 =2-3 min. Metal ion translocation triggers a 20 Å relocation of the toggle at both nanoswitches, entailing major geometric and electronic changes.
Soumen De, Susnata Pramanik, and Michael Schmittel
Royal Society of Chemistry (RSC)
Dual coordination at two distinct nitrogen binding sites in various ditopic azabipyridines and azaterpyridines was evaluated by preparing 3- and 4-component complexes. The 4-aza-2,2'-bipyridine unit was implemented into a nanoswitch and used for reversible switching between open and closed forms.
Manik Lal Saha, Soumen De, Susnata Pramanik, and Michael Schmittel
Royal Society of Chemistry (RSC)
Over years, mathematicians, biologists and chemists have capitalised on the highly useful concept of orthogonality for developing sophisticated complex systems. The use of orthogonal pairs ensures that any modification made on one pair does not propagate any effect onto the other. While the concept equally pertains to dynamic supramolecular interactions, interference-free self-assembly built on multiple orthogonal interactions is still limited and the underlying notions are not yet firmly established. Herein, we identify, classify and evaluate dynamic interactions in various orthogonal settings in order to distill out general recommendations for reliable dynamic orthogonality. Our classification has to exclude templating, allosteric and/or cooperative effects as the latter are specific for individual cases only.
Michael Schmittel, Susnata Pramanik, and Soumen De
Royal Society of Chemistry (RSC)
The two states of a new nanomechanical switch were quantitatively and reversibly populated in several subsequent switching cycles using either Cu(+) or cyclam as chemical inputs. State II was demonstrated to cis-trans isomerise diazastilbene upon irradiation selectively in the presence of stilbene, and even to operate as a photocatalyst.
Manik Lal Saha, Susnata Pramanik, and Michael Schmittel
Royal Society of Chemistry (RSC)
Using principles of completive and integrative self-sorting, a clean supramolecule-to-supramolecule transformation is realised that involves fusion of a 3-component rectangle and a 2-component equilateral triangle into a 5-component scalene triangle. While the spontaneous process takes 15 h at 25 °C, the catalytic transformation is completed within 1 h.
Michael Schmittel, Soumen De, and Susnata Pramanik
Georg Thieme Verlag KG
We describe the synthesis of four bromo-substituted azabipyridines and two bromo-substituted azaterpyridines through a series of palladium-catalyzed cross-coupling reactions. Both the azabipyridine and azaterpyridine heterocycles contain two orthogonal binding motifs, the value of which has been demonstrated recently in a nanomechanical switch for triggering organocatalysis. The bromo functionality allows heterocyclic ligands to be attached to larger frameworks.
Michael Schmittel, Soumen De, and Susnata Pramanik
Wiley
Flip a switch: a nanoswitch uses chemical inputs to turn an organocatalytic Knoevenagel reaction on and off (see scheme: R=reactant, P=product). To stop catalysis the chemical input (pink and green) wraps around the inhibitory segment of the nanoswitch to effect release or unlocking of the switch. The process can run reversibly over three cycles without loss of activity.