The selective intercalation of organic carboxylates and sulfonates into hydroxy double salts

Abstract

This paper reports the first systematic investigation of the selectivity of organic guest intercalation into hydroxy double salts. The organic guests 1,2-and 1,4-benzenedicarboxylate (1,2-and 1,4-BDC) have been incorporated into a range of hydroxy double salts by anion exchange. O were prepared, and the resultant materials fully characterized. 1,5-and 2,6-Napthalanedisulfonate (1,5-and 2,6-NDS) were also successfully intercalated into the [Zn 5 (OH) 8 ](NO 3 ) 2 $yH 2 O material. It was found that the initial anions are almost completely replaced by the new organic guests in the majority of cases. Selected reactions were investigated by in situ X-ray diffraction, and the reactions observed to proceed directly from the host to the product largely under nucleation control. No intermediate phases were detected. The competitive intercalation of isomeric pairs of guest anions was explored, and very high degrees of preferential intercalation found for 1,4-over 1,2-BDC into all hydroxy double salts (HDSs) studied, and for 2,6-over 1,5-NDS into [Zn 5 (OH) 8 ](NO 3 ) 2 $yH 2 O. The selectivity was found to be largely invariant with reaction time, reaction temperature, solvent system, and guest concentration. It was also observed to be very similar across all the HDSs explored. In situ diffraction and NMR demonstrate that the selective intercalation is a thermodynamically controlled phenomenon. It is therefore suggested that preferential intercalation is governed in the main by the strength of the interactions between the HDS layers and the guest ions.

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“…The second method comprised a Principal Component Analysis (PCA) using protocols developed in previous reports. 39,40 Statistical analyses were undertaken using the ''R'' package (http://r-project.org) and the pcaMethods module. 41 PCA involves taking a number of correlated variables in a large dataset (diffracted intensity, peak position, time, etc.…”

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New biocompatible hydroxy double salts and their drug delivery properties

“…x )(OH) 4-y ]X ny/n •zH 2 O, in which M 2+ and Me 2+ correspond to divalent metals ions such as Cu 2+ , Co 2+ , Ni 2+ , or Zn 2+ and X nis an exchangeable interlayer anion. 4,5 An example of an HDS is the zinc basic salt (ZBS) [Zn 5 (OH) 8 ](NO 3 ) 2 •2H 2 O. [6][7][8] This comprise layers of edge-sharing M(OH) 6 octahedra with one third of the octahedral sites vacant and additional Zn 2+ cations situated above and below the layer in tetrahedral sites.…”