Towards polynuclear metal complexes with enhanced bioactivities: Synthesis, crystal structures and DNA cleaving activities of CuII, NiII, ZnII, CoII and MnII complexes derived from 4-carboxy-1-(4-carboxybenzyl) pyridinium bromide

Sensitive and Specific Guest Recognition through Pyridinium-Modification in Spindle-Like Coordination Containers

An elaborately designed pyridinium-functionalized octanuclear zinc(II) coordination container 1-Zn was prepared through the self-assembly of Zn²⁺ , p-tert-butylsulfonylcalix[4]arene, and pyridinium-functionalized angular flexible dicarboxylate linker (H₂ BrL1). The structure was determined by a single-crystal X-ray diffractometer. 1-Zn displays highly sensitive and specific recognition to 2-picolylamine as revealed by drastic blueshifts of the absorption and emission spectra, ascribed to the decrease of intramolecular charge transfer (ICT) character of the container and the occurrence of intermolecular charge transfer between the host and guest molecules. The intramolecular charge transfer plays a key role in the modulation of the electronic properties and is tunable through endo-encapsulation of specific guest molecules.

Lanthanum-Based Metal-Organic Frameworks for Specific Detection of Sudan Virus RNA Conservative Sequences down to Single-Base Mismatch

Reactions of La(NO₃)₃·6H₂O with the polar, tritopic quaternized carboxylate ligands N-carboxymethyl-3,5-dicarboxylpyridinium bromide (H₃CmdcpBr) and N-(4-carboxybenzyl)-3,5-dicarboxylpyridinium bromide (H₃CbdcpBr) afford two water-stable metal-organic frameworks (MOFs) of {[La₄(Cmdcp)₆(H₂O)₉]}_n (1, 3D) and {[La₂(Cbdcp)₃(H₂O)₁₀]}_n (2, 2D). MOFs 1 and 2 absorb the carboxyfluorescein (FAM)-tagged probe DNA (P-DNA) and quench the fluorescence of FAM via a photoinduced electron transfer (PET) process. The nonemissive P-DNA@MOF hybrids thus formed in turn function as sensing platforms to distinguish conservative linear, single-stranded RNA sequences of Sudan virus with high selectivity and low detection limits of 112 and 67 pM, respectively (at a signal-to-noise ratio of 3). These hybrids also exhibit high specificity and discriminate down to single-base mismatch RNA sequences.

Formation of supramolecular hetero-triads by controlling the hydrogen bonding of conjugate bases with a diprotonated porphyrin based on electrostatic interaction

The thermodynamic stability of diprotonated saddle-distorted dodecaphenylporphyrin was controlled by the hydrogen-bonding strength of conjugate bases of strong acids or acids having positively charged moieties.

A zwitterionic 1D/2D polymer co-crystal and its polymorphic sub-components: a highly selective sensing platform for HIV ds-DNA sequences

Polymorphic compounds {[Cu(dcbb)₂(H₂O)₂]·10H₂O}_n (2, 1D chain), [Cu(dcbb)₂]_n (3, 2D layer) and their co-crystal {[Cu(dcbb)₂(H₂O)][Cu(dcbb)₂]₂}_n (4) have been prepared from the reaction of [Na(dcbb)(H₂O)]_n (1) with Cu(NO₃)₂·3H₂O at different temperatures.

Five water-soluble zwitterionic copper(ii)-carboxylate polymers: role of dipyridyl coligands in enhancing the DNA-binding, cleaving and anticancer activities

Five water-soluble zwitterionic copper-carboxylate polymers were prepared and their DNA-binding, cleaving and anticancer activities were studied.

Lanthanide-Based Polymers with Charged Ligand Backbones: Triple-Stranded Chain Structures and their DNA Cleavage Studies

Four rare-earth metal complexes, [Ln(Ccbp)3(H2O)3]n (Ln = La (1), Ce (2), Pr (3) and Nd (4)) are synthesised from the ligand H2CcbpBr (H2CcbpBr = 4-carboxy-1-(4-carboxybenzyl)pyridinium bromide) and the respective lanthanide metal ions. Complexes 1–4 are isostructural in that every three Ccbp– ligands juxtapose two Ln3+ ions in a monodentate coordination mode to form triple-stranded one-dimensional chain structures. Each central Ln3+ atom further associates with three H2O molecules, furnishing a monocapped square-antiprism geometry. Agarose gel electrophoresis studies indicate that 1–4 are capable of cleaving DNA in the presence of H2O2, most probably via an oxidative cleavage mechanism. Complexes 1 and 2 exhibited catalytic efficiencies (kmax/KM) of 37.69 and 34.11 h–1 mM–1, and are approx. 15- and 20-fold more effective than those of complexes 3 (kmax/KM = 1.75 h–1 mM–1) and 4 (kmax/KM = 2.21 h–1 mM–1).

Bent tritopic carboxylates for coordination networks: clues to the origin of self-penetration

We suggest in this paper that the combinative use of bent tritopic carboxylate, linear dipyridyl and adaptable Cu²⁺ ion leads to a higher probability of self-penetrated polymeric networks.

A Three-Component 1D/2D → 2D Interpenetrated Coordination Network: Structure and Gas Adsorption Studies

We herein report a Cd-based coordination polymer containing three integrated polymeric components: two neutral and entangled two-dimensional (6,3) nets and one zwitterionic one-dimensional polymer with corner-sharing double-stranded chains propagating along the c-direction to lock the consecutive ligand struts of the (6,3) nets. Despite a sophisticated entanglement, this coordination polymer is porous to selectively adsorb CO2.