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 display highly 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 % 6t o% 10). Moreover, these species exhibit pronounced topological changes when aw eak non-bonding NH•••p aryl interaction is introduced. Finally,t he NH-bridged chloride binding affinities have been calculated and benchmarked along with the existing experimental data available for monomeric cyclodiphosphazanes. Our results underscore these species as promising hydrogen bond donors for supramolecular host-guest applications.

Mechanosynthesis of Higher‐Order Cocrystals: Tuning Order, Functionality and Size in Cocrystal Design**

“…In line with previous reports, [33] this variation in the HB donor capacity of Se 2 P 2 N 2 explains the observed Se 2 P 2 N 2 exo,exo conformation in all cocrystals containing DMU (B2-Form I, B2-Form II and T1)s ince it enables the formation of bifurcated HB interactions with the oxygen acceptor of DMU.T he calculated MEPs also support the observed orthogonality of hydrogen-and halogen-bonding interactions in ternary cocrystal T1.T his is evident from the MEPs as the NH donors on Se 2 P 2 N 2 are more likely to be engaged in bifurcated HB interactions with the carbonyl acceptor of DMU (i.e.t he strongest pairing according to the calculated potentials), allowing the Se atoms to freely engage in Se•••Br interactions with DBTFB.…”

“…[39] This approach has recently been used in the synthesis of arange of versatile monomeric, dimeric and trimeric halide hosts. [33] In solution, the symmetrically substituted cis-Se oxidized cyclodiphosph(V/V)azane comprising four tert-butyl groups-[ t BuNH(P(Se)m-N t Bu)] 2 ,( Se 2 P 2 N 2 )-has been reported to cocrystallize with N, N'-dimethylurea (DMU)a nd 1,4-dibromotetrafluorobenzene( DBTFB)i na1:1r atio to form binary (Se 2 P 2 N 2 )•(DBTFB)a nd (Se 2 P 2 N 2 )•(DMU)c ocrystals (B1 and B2,respectively). [36] Building block Se 2 P 2 N 2 (1), which adopts an exo, endo (Z, E)c onformation (CSD code XOTGAO) [56] rearranges to an exo, exo (Z, Z)c onformation, Se 2 P 2 N 2 exo,exo , [57] upon the formation of R 2 1 (8) bifurcated HBs with DMU in B2.Binary cocrystal B2 can be isolated in two different polymorphic forms (i.e., B2-Form I and B2-Form II, Pna2 1 and P2 1 /c, respectively).…”

“…Recently,c yclodiphosphazane species [30,31] have been demonstrated as robust [32] and versatile [33][34][35] supramolecular building blocks in binary cocrystal formation. [33,[36][37][38][39] However their use for the synthesis of multicomponent crystals beyond binary systems,remains unexplored.…”

Mechanosynthesis of Higher‐Order Cocrystals: Tuning Order, Functionality and Size in Cocrystal Design**

“…Recently, cyclodiphosphazane species[ 30 , 31 ] have been demonstrated as robust [32] and versatile[ 33 , 34 , 35 ] supramolecular building blocks in binary cocrystal formation. [ 33 , 36 , 37 , 38 , 39 ] However their use for the synthesis of multicomponent crystals beyond binary systems, remains unexplored.…”

Synergic Topological- and Size-Control on Phosphazane Chemistry: First Unfolded Hybrid Tetrameric Macrocycle

“…[1][2][3][4] In this context, cyclodiphosphazane-based inorganic macrocycles have drawn attention due to both their promise in host guest chemistry and anion sensing. [5][6][7][8][9][10][11][12][13][14] Cyclophosphazane species have been widely explored over the past decades due to their chemical versatility, [15] action as excellent neutral and/or anionic ligands for metal coordination [16][17][18][19][20][21][22][23] and building blocks for the construction of larger molecules, as well as utility in biological applications and supramolecular chemistry. [12,13,[24][25][26][27][28][29][30][31][32] Depending on the nature of the bifunctional linkers employed, their reaction with dichlorocyclodiphosphazane, [ClP(μ-N t Bu)] 2 (1), yields differently-sized fully inorganic or hybrid macrocycles.…”