Water-Soluble Squaramide Dihydrates: N-Methylation Modulates the Occurrence of One- and Two-Dimensional Water Clusters through Hydrogen Bonding and Dipolar Interactions

Water confined in molecular size domains is distinct to bulk water. The altered interactions between adjacent water molecules, and between water molecules and molecular wall components of the confinement system, determine aspects of important phenomena in material science, biology, and nanotechnology. The structural determination of confined water, however, has proven to be challenging. Here, we describe the crystal structures of three related squaramides 1–3 whose molecular structures are modulated by the gradual incorporation of N-methyl groups to the squaramide moiety. The three squaramides differ in their hydrogen bonding capabilities due to the different degree of N-methylation of each…

Grafted squaramide monoamine nanoparticles as simple systems for sulfate recognition in pure water.

New simple systems formed by a chain containing a squaramide function and a quaternised amine group attached to boehmite or silica-coated boehmite nanoparticles are able to discriminate anions in pure water.

Conformational Isomerism: Influence of the Z / E Isomerism on the Pathway Complexity of a Squaramide‐Based Macrocycle (Small 7/2021)

Influence of theZ/EIsomerism on the Pathway Complexity of a Squaramide‐Based Macrocycle

The rising interest on pathway complexity in supramolecular polymerization has prompted the finding of novel monomer designs able to stabilize kinetically trapped species and generate supramolecular polymorphs. In the present work, the exploitation of the Z/E (geometrical) isomerism of squaramide (SQ) units to produce various self-assembled isoforms and complex supramolecular polymerization pathways in methylcyclohexane/CHCl3 mixtures is reported for the first time. This is achieved by using a new bissquaramidic macrocycle (MSq) that self-assembles into two markedly different thermodynamic aggregates, AggA (discrete cyclic structures) and AggB (fibrillar structures), depending on the solven…

Dual role of silver in a fluorogenic N-squaraine probe based on Ag(i)–π interactions

In the presence of Ag(I), the monoanion of cyano-N-squaraine (I) generates an intense fluorescence turn-on response. Experimental evidence and DFT calculations reveal a sequence of deprotonation-coordination events in which the Ag(I) ions play a dual role as a Lewis acid and coordinating metal. The observed effect is highly selective for Ag(I) compared to other metals.

Binding Mode and Selectivity of a Scorpiand-Like Polyamine Ligand to Single- and Double-Stranded DNA and RNA: Metal- and pH-Driven Modulation

The interaction of a polyazacyclophane ligand having an ethylamine pendant arm functionalized with an anthryl group (L), with the single-stranded polynucleotides polyA, polyG, polyU, and polyC as well as with the double-stranded polynucleotides polyA-polyU, poly(dAT)(2), and poly(dGC)(2) has been followed by UV/Vis titration, steady state fluorescence spectroscopy, and thermal denaturation measurements. In the case of the single-stranded polynucleotides, the UV/Vis and fluorescence titrations permit to distinguish between sequences containing purine and pyrimidine bases. For the double-stranded polynucleotides the UV/Vis measurements show for all of them hypochromicity and bathochromic shif…

Squaramide-based reagent for selective chromogenic sensing of Cu(II) through a zwitterion radical.

A minimalist squaramide-based chemodosimeter for Cu(2+) is described. Upon selective chelation to 2, Cu(2+) induces the formation of a highly colored zwitterionic radical, which is kinetically stable for hours. The presence of a radical is confirmed by EPR and ESI-MS. It is then possible to use reagent 2 for visual and selective sensing of Cu(2+) at neutral pH.

CCDC 2071315: Experimental Crystal Structure Determination

Related Article: Manel Vega, Salvador Blasco, Enrique García-España, Bartolomé Soberats, Antonio Frontera, Carmen Rotger, Antonio Costa|2021|Dalton Trans.|50|9367|doi:10.1039/D1DT01408K

CCDC 1814073: Experimental Crystal Structure Determination

Related Article: Marta Ximenis, Javier Pitarch-Jarque, Salvador Blasco, Carmen Rotger, Enrique García-España, Antonio Costa|2018|Cryst.Growth Des.|18|4420|doi:10.1021/acs.cgd.8b00401

CCDC 1814074: Experimental Crystal Structure Determination

Related Article: Marta Ximenis, Javier Pitarch-Jarque, Salvador Blasco, Carmen Rotger, Enrique García-España, Antonio Costa|2018|Cryst.Growth Des.|18|4420|doi:10.1021/acs.cgd.8b00401

CCDC 1814075: Experimental Crystal Structure Determination

Related Article: Marta Ximenis, Javier Pitarch-Jarque, Salvador Blasco, Carmen Rotger, Enrique García-España, Antonio Costa|2018|Cryst.Growth Des.|18|4420|doi:10.1021/acs.cgd.8b00401