A Convenient Route to Diversely Substituted Icosahedral Closomer Nanoscaffolds

Abstract

The design and synthesis of icosahedral polyhedral borane closomer motifs based upon carbonate and carbamate anchoring groups for biomedical applications are described. Dodecacarbamate closomers containing easily accessible groups of interest at their linker termini were synthesized via activation of the B-OH vertices as aryl carbonates and their subsequent reaction with primary amines. Novel dodecacarbonate closomers were successfully synthesized for the first time by reacting [closo-B12(OH)12]2− with an excess of respective aryl chloroformates, utilizing relatively short reaction times, mild conditions and simple purification strategies, all of which had previously presented difficulties in closomer chemistry. This methodology for the 12-fold degenerate synthesis of carbonate and carbamate closomers will greatly facilitate further exploration of closomers as monodisperse nanomolecular delivery platforms.

Atomically precise organomimetic cluster nanomolecules assembled via perfluoroaryl-thiol SNAr chemistry

“…Overall, these experiments suggest that using the developed method, it is possible to rapidly assemble OCNs via S N Ar chemistry under very mild and operationally simple conditions mimicking the simplicity of the thiol-capped AuNPs assembly. Furthermore, unlike the previously developed Huisgen “click” cycloaddition and carbamate functionalization strategies of inherently non-rigid B 12 -based clusters, which require elevated temperatures, long reaction times (days) and a large excess of reagents (4–5 fold per vertex), the perfluoroaryl-thiol S N Ar chemistry described here proceeds using significantly milder conditions 33,34 .…”

Synthesis and Applications of Perfunctionalized Boron Clusters

“…83 As with the formation of closo -[H 3 NB 12 Cl 11 ] 1− , Duttwyler and co-workers described a simplified synthesis of closo -[B 12 Cl 11 OH] 2− using SO 2 Cl 2 instead of chlorine gas and showed additional reactivity at the hydroxyl group to produce closo -[B 12 Cl 11 O(SO 2 CF 3 )] 2− and closo -[B 12 Cl 11 OTs] 2− respectively. 82 A summary of these functionalization methods is shown in Figure 5.…”

“…80 This remains the only reported peralkylation of dodecaborate, and the only homopersubstituted dodecaborate that contains B–C linkages. b) Halogenation 52,65–68 c) Hydroxylation 69–71,81 d) Carbamation 82 e) Carbonation 82 f) Esterification 72 g) Etherification 71 .…”

Rapid synthesis of redox-active dodecaborane B12(OR)12clusters under ambient conditions

“…16,23 In the past two decades, persubstitution of [B 12 H 12 ] 2− was improved with new synthetic methods and extended towards other functional groups including [B 12 Me 12 ] 2− and [B 12 (OH) 12 ] 2−.24–28 Among the perfunctionalized derivatives synthesized, closo -[B 12 (OH) 12 ] 2− is particularly appealing, as it is capable of undergoing further functionalization by forming ether, ester, carbonate, and carbamate linkages. 27,29–31 …”