N‐Bridged Acyclic Trimeric Poly‐Cyclodiphosphazanes: Highly Tuneable Cyclodiphosphazane Building Blocks

Abstract

We have synthesized ac ompletely new family of acyclic trimeric cyclodiphosphazane compounds comprising NH, N i Pr,N t Bu and NPh bridging groups.Inaddition, the first NH-bridged acyclic dimeric cyclophosphazane has been produced. The trimeric species displayh ighly tuneable characteristics so that the distance between the terminal N(H)R moieties can be readily modulated by the steric bulk present in the bridging groups (ranging from % 6to% 10). Moreover,these species exhibit pronounced topological changes when aw eak non-bonding NH•••p aryl interaction is introduced. Finally,the NH-bridged chloride binding affinities have been calculated and benchmarked along with the existing experimental data available for monomeric cyclodiphosphazanes.O ur results underscore these species as promising hydrogen bond donors for supramolecular host-guest applications.

NH-bridged Dimeric Phosphazanes: Inorganic Molecular Switches based on Anion Responsive Bifurcated to Trifurcated Hydrogen Bond Transitions

“…[56][57][58] However, novel topologically tuneable N-bridged acyclic oligo-P III 2N2 dimeric and trimeric species have been recently reported. 59 The latter comprise different substituents (e.g., H, i Pr, Ph, and t Bu) at the two backbone bridging positions, which determine their final topological conformation. This report represents the first rational selection of different topological conformations using noncovalent interactions in the phosphazane P III 2N2 family.…”

“…In addition, theoretical studies predict acyclic dimeric and trimeric P V 2N2species as topologically tuneable frameworks with superior halide receptors with increased binding ability towards chlorides compared to their monomeric counterparts (i.e., squaramide and thiourea R 2 1(8) type building blocks). 59 Noteworthy, is that anion binding has been successfully used as a chemical stimulus in a wide range of molecular switches. [60][61][62][63][64][65] The previously demonstrated rational selection of different topological conformations in dimeric and trimeric acyclic P III 2N2 phosphazane species, combined with the predicted superior halide binding ability of P V 2N2, suggests their suitability as potential main group building blocks towards chemically responsive frameworks based on a fully inorganic backbone.…”

“…The basic building block in our studies, compound 1, can be obtained via the single step reaction of Cl[P(µ-N t Bu)]2NH t Bu with LiNH2 in THF at room temperature (Scheme S1). 59,66 This recently reported synthetic methodology allows for a simple and straightforward route to NHbridged acyclic dimeric P III 2N2. 59 Compound 1 was then oxidised to form the NH-bridged acyclic dimeric-P V 2N2 counterpart to enable its HB ability (Figure 2A).…”

“…59,66 This recently reported synthetic methodology allows for a simple and straightforward route to NHbridged acyclic dimeric P III 2N2. 59 Compound 1 was then oxidised to form the NH-bridged acyclic dimeric-P V 2N2 counterpart to enable its HB ability (Figure 2A). Treatment of 1 with six equivalents of H2O2, added dropwise at 0 °C, afforded its oxygen oxidised counterpart 2 (Scheme S2).…”

Direct and Telescopic Mechanochemical Synthesis of Higher-order Organic-Inorganic Hybrid Cocrystals: Tuning Order, Functionality and Size in Cocrystal Design

“…Recently, our group has demonstrated the robustness and versatility of cyclodiphosphazanes [32] as a supramolecular building block, [33][34] by synthesizing a series of binary cocrystals, sustained by hydrogen-and halogen-bonding interactions. [34] However their use as inorganic building blocks for the synthesis of "neutral" (i.e., non-ionic) and or ionic multicomponent cocrystaline systems (ICCs) -beyond binary systems -remains unexplored.…”