An in solution adsorption characterization technique based on the response to an external magnetic field of porous paramagnetic materials: application on supramolecular metal–adenine frameworks containing heterometallic heptameric clusters

Abstract

Herein we explore the opportunities arising from combining magnetic properties and porosity in metal-organic materials. In this sense, we have prepared an adenine based homometallic wheel-shaped heptameric [Cu7(µ-adeninato)6(µ3-OH)6(µ-OH2)4]2+ entity containing...

Isoreticular Chemistry and Applications of Supramolecularly Assembled Copper–Adenine Porous Materials

“…At this point, encouraged by the achieved control on the porosity of this family of SMOFs and also by their great chemical stability and insolubility in aqueous media, we decided to check their viability as drug carriers incorporating different pharmaceutically active molecules such as the antitumoral 5-fluorouracil (5-FU), the antibiotic 4-aminosalicylic acid (4-ASA), 5-aminosalicylic acid (5-ASA), which is used to treat inflammatory bowel diseases, and the antiarthritic allopurinol (ALLO). The loading of these drugs in aqueous solution was monitored by means of a novel magnetic sustentation procedure recently developed by us. ,, The method allows to obtain the amount of guest molecules incorporated by a paramagnetic porous material in aqueous solution, and it is based on the determination of the critical magnetic field (H) that is necessary to retain the particles of this material attached to the poles of a magnet (Figure S24). There is a linear correlation (eq ) between the mass percentage of the loading molecule by the porous material and the critical H, in such a way that the greater the deviation with respect to the critical magnetic value of the pristine material (without loading), the greater the mass of the captured guest molecules. M M ( F ) = A ′ · H − B ′ where M M( F ) corresponds to the captured mass of the adsorbate in the material, H is the critical magnetic field determined from magnetic sustentation experiments, and A′ and B′ are constant values which must be previously determined by means of a calibration procedure that requires 1 H-NMR measurements using an internal standard ( t -BuOH) and repeating the adsorption procedure but using D 2 O.…”

“…The loading of these drugs in aqueous solution was monitored by means of a novel magnetic sustentation procedure recently developed by us. 32,51,52 The method allows to obtain the amount of guest molecules incorporated by a paramagnetic porous material in aqueous solution, and it is based on the determination of the critical magnetic field (H) that is necessary to retain the particles of this material attached to the poles of a magnet (Figure S24). There is a linear correlation (eq 1) between the mass percentage of the loading molecule by the porous material and the critical H, in such a way that the greater the deviation with respect to the critical magnetic value of the pristine material (without loading), the greater the mass of the captured guest molecules.…”