Esterase-induced release of a theranostic prodrug in lysosomes for improved therapeutic efficacy and lower systemic toxicity.

5-Fluorouracil (5-FU) is the third most used chemotherapeutic agent. Despite being a frontline drug, it inhibits thymidylate synthase in malignant and non-malignant cells, which adds to its severe systemic toxicity. To address this, a new physiologically benign theranostic prodrug of 5-FU, named PD, has been developed by covalently linking 5-FU with a fluorophore and a lysosome-targeting morpholine moiety through an ester functionality.

From construction to application of a new generation of interlocked molecules composed of heteroditopic wheels.

Over the last few decades, research on mechanically interlocked molecules has significantly evolved owing to their unique structural features and interesting properties. A substantial percentage of the reported works have focused on the synthetic strategies, leading to the preparation of functional MIMs for their applications in the chemical, materials, and biomedical sciences. Importantly, various macrocyclic wheels with specific heteroditopicity (including phenanthroline, amide, amine, oxy-ether, isophthalamide, calixarene and triazole) and threading axles (bipyridine, phenanthroline, pyridinium, triazolium, ) have been designed to synthesize targeted multifunctional mononuclear/multinuclear pseudorotaxanes, rotaxanes and catenanes.

Development of fluorophoric [2]pseudorotaxanes and [2]rotaxane: selective sensing of Zn(II).

Fluorophoric [2]pseudorotaxanes {NiPR1(ClO4)2-NiPR3(ClO4)2} are synthesized by utilizing newly designed fluorophoric bidentate ligands (L1-L3) and a heteroditopic naphthalene containing macrocycle (NaphMC) with high yields Ni(II) templation and π-π stacking interactions. Subsequently, a fluorophoric [2]rotaxane (NAPRTX) is established through a Cu(I) catalysed click reaction between an azide terminated pseudorotaxane, {NiPR4(ClO4)2}, which contains the newly designed fluorophoric ligand L4, and alkyne terminated bulky stopper units. All these fluorophoric [2]pseudorotaxanes and the [2]rotaxane were characterized using numerous techniques such as mass spectrometry, NMR, UV/Vis, PL, and elemental analysis, wherever applicable.

NDI-integrated rotaxane/catenane and their interactions with anions.

Complexation of alkali and alkaline earth metal ions with the heteroditopic Phen-ester oxy-ether macrocyclic wheel () is established for the synthesis of interlocked molecular systems. The single crystal X-ray structure of Na-bound confirms the hexacoordinated geometry around the Na ion in the macrocycle. Further, Ca-ion-bound (Ca-) is explored with a fluorophoric azide-terminated NDI (naphthalene diimide) axle (NDIAz) for the synthesis of fluorophoric [2]rotaxane (NDIROT) and [2]catenane (NDICAT) Cu(I)-catalyzed cycloaddition reaction.

A Cd(ii) and Zn(ii) selective naphthyl based [2]rotaxane acts as an exclusive Zn(ii) sensor upon further functionalization with pyrene.

A new multi-functional [2]rotaxane, ROTX, has been synthesized via a Cu(i) catalysed azide-alkyne cycloaddition reaction between Ni(ii) templated azide terminated pseudorotaxane composed of a naphthalene based heteroditopic wheel, NaphMC, and an alkyne terminated stopper. Subsequently, ROTX has been functionalized with pyrene moieties to develop a bifluorophoric [2]rotaxane, PYROTX, having naphthalene and pyrene moieties. Detailed characterization of these two rotaxanes is performed by utilizing several techniques such as ESI-MS, (1D and 2D) NMR, UV/Vis and PL studies.

Cu(ii) templated formation of [n]pseudorotaxanes (n = 2, 3, 4) using a tris-amino ether macrocyclic wheel and multidentate axles.

A tris-amine and oxy-ether functionalised macrocyclic wheel (NaphMC) and various phenanthroline based multidentate axles (L1, L2 and L3) are utilised for the formation of [n]pseudorotaxanes (n = 2, 3, 4) in high yields via Cu(ii) temptation and π-π stacking interactions. The systematic development of threaded supramolecular architectures i.e.

An integrated urea and halogen bond donor based receptor for superior and selective sensing of phosphates.

A new RuII based bis-heteroleptic ditopic receptor, 1[PF6]2 (C44H33F12IN10OP2Ru), having integrated anion binding iodotriazole (halogen bond donor) and urea units (-NH bond donor) is employed for selective sensing of phosphates (e.g., H2PO4- and HP2O73-).

A multifunctional catenated host for the efficient binding of Eu and Gd.

A new multifunctional [2]catenane is synthesized by using a phenanthroline-based heteroditopic wheel and Axle, which acts as a receptor for the efficient binding of lanthanide ions such as Eu3+ and Gd3+.

Naphthalene containing amino-ether macrocycle based Cu(ii) templated [2]pseudorotaxanes and OFF/ON fluorescence switching via axle substitution.

A new naphthalene containing macrocycle, NaphMC, and a new fluorophoric bidentate linear axle derivative of 5,5'-dimethyl-2,2'-bipyridine (L3) along with two other ligands 1,10-phenanthroline (L1) and 5,5'-dimethyl-2,2'-bipyridine (L2) are explored towards the synthesis of Cu(ii) templated [2]pseudorotaxanes. All ternary complexes are well characterized by ESI-MS, UV/Vis, EPR spectroscopy, elemental analysis and emission spectroscopic studies. Single crystal X-ray diffraction studies confirm the geometry around the Cu(ii) center as a distorted trigonal bipyramid via the contribution of [3 + 2] orthogonal motifs of the wheel (NaphMC) and the bidentate chelating ligands L1 and L2 in the cases of pseudorotaxanes, CuPR1 and CuPR2, respectively.

Polyamide-Polyamine Cryptand as Dicarboxylate Receptor: Dianion Binding Studies in the Solid State, in Solution, and in the Gas Phase.

Polyamide-polyamine hybrid macrobicycle L is explored with respect to its ability to bind α,ω-dicarboxylate anions. Potentiometric studies of protonated L with the series of dianions from succinate (suc) through glutarate (glu), α-ketoglutarate (kglu), adipate (adi), pimelate (pim), suberate (sub), to azelate (aze) have shown adipate preference with association constant value of K = 4900 M in a HO/DMSO (50:50 v/v) binary solvent mixture. The binding constant increases from glu to adi and then continuously decreases with the length of the anion chain.

Syntheses of metallo-pseudorotaxanes, rotaxane and post-synthetically functionalized rotaxane: a comprehensive spectroscopic study and dynamic properties.

Herein, a bis-amido tris-amine macrocycle and five bipyridine-based bidentate chelating ligands were investigated towards various divalent transition metal ion (Ni, Co, Cu, and Zn)-templated syntheses of metallo [2]pseudorotaxanes. The formation of these ternary complexes was elucidated via different spectroscopic techniques such as ESI-MS, absorption spectroscopy, EPR spectroscopy, and single-crystal X-ray diffraction studies wherever possible. Azide-terminated Ni, Co, Cu, Zn-templated [2]pseudorotaxanes were explored to generate [2]rotaxane, ROT, via reaction with an alkyne-terminated triphenylene unit as a stopper under the mild reaction condition of the Cu-catalyzed azide-alkyne cycloaddition reaction.

Amino-ether macrocycle that forms CuII templated threaded heteroleptic complexes: a detailed selectivity, structural and theoretical investigations.

A new oxy(ether)tris(amine) macrocycle, MC has been synthesized for CuII complex formation within the cavity of the macrocyclic wheel in endotopic fashion. This complex is further reacted with the bidentate chelating ligands, 1,10-phenanthroline (L1), 2,2′-bipyridyl (L2), 4,4′-dimethyl-2,2′-bipyridyl (L3) and 5,5′-dimethyl-2,2′-bipyridyl (L4) to achieve the pseudorotaxanes PRT1–PRT4, respectively. These bis-heteroleptic complexes were characterized by the electrospray ionization mass spectrometry (ESI-MS), UV/Vis, EPR spectroscopy and Single-crystal X-ray structural analysis.