A Robust, Divalent, Phosphaza-bicyclo[2.2.2]octane Connector Provides Access to Cage-Dense Inorganic Polymers and Networks

Abstract

While polymers containing chain or ring motifs in their backbone are ubiquitous, those containing well-defined molecular cages are very rare and essentially unknown for the inorganic elements. We report that a rigid and dinucleophilic cage (PNSiMe3)2(NMe)6, which is chemically robust and accessible on a multi-gram scale from commercial precursors, serves as a linear and divalent connector that forms cage-dense inorganic materials. Reaction of the cage with various ditopic P(III) dihalide comonomers proceeded via Me3SiCl elimination to give high molecular weight (30 000–70 000 g mol–1), solution-processable polymers that form free-standing films. The end groups of the polymers could be tuned to engender orthogonal reactivity and form block copolymers. Networked cage-dense materials could be accessed by using PCl3 as a tritopic P(III) linker. Detailed mechanistic studies implicate a stepwise polycondensation that proceeds via phosphino–phosphonium ion intermediates, prior to Me3SiCl loss. Thus, metathesis between the dinucleophilic cage and polyhalides represents a general strategy to making cage-dense polymers, setting the stage for systematically understanding the consequences of the three-dimensional microstructure on macroscopic material properties.

Multicomponent Synthesis of Poly(α-aminophosphine chalcogenide)s and Subsequent Depolymerization

“…Similar incompatibility of inorganic polymers with GPC columns has been acknowledged. 21,22 The notable low solubility of 4−7 likely also biases the M W values toward the more soluble oligomeric molecules. This prompted the analysis of chain lengths by alternative experimental means.…”

“…The GPC analysis was inconsistent with M w data obtained by both end-group analysis and DOSY ( vide infra ), likely because of the interactions between the polar PCh (EN; P = 2.19, O = 3.44, S = 2.58) and N–H functional groups and the stationary phase of the GPC column. Similar incompatibility of inorganic polymers with GPC columns has been acknowledged. , The notable low solubility of 4 – 7 likely also biases the M W values toward the more soluble oligomeric molecules. This prompted the analysis of chain lengths by alternative experimental means.…”

An Improved Synthesis of PN‐adamantanoid Cages P4(NR)6 and a Mechanistic Study of their Fourfold Oxidation

“…Fluorinated grease, Krytox, was used for assembling all ground glass joints. Nuclear magnetic resonance spectra are referenced to tetramethylsilane ( 1 H, 13 C) and H 3 PO 4 ( 31 P) on a Bruker AV-300 spectrometer or a Bruker AV-400 spectrometer with residual solvent used for chemical shift calibration. Samples for NMR spectroscopy were prepared and sealed inside the glovebox with Parafilm or in a J-Young tube before removal into ambient atmosphere.…”

“…The crystals were dried under high vacuum for 24 h at ambient temperature to obtain 2Et as a colourless powder. Yield: 6.14 g (8.40 mmol, 84%); 1 H NMR (300 MHz, Benzene-d 6 ) δ 3.41 (dq, J = 7.0, 7.0 Hz, 12H), 1.19 (t, J = 7.0 Hz, 18H), 0.27 (s, 36H), 1 H{ 31 P} NMR (300 MHz, Benzene-d 6 ) δ 3.41 (q, J = 7.0 Hz, 12H), 1.19 (t, J = 7.0 Hz, 18H), 0.27 (s, 36H), 13 16) Å, β = 90.864(4)°, V = 4211.9(7) Å 3 , Z = 4, T = 211.00 K, μ(MoKα) = 0.322 mm À 1 , Dcalc = 1.153 g/cm 3 , 171136 reflections measured (3.706°� 2Θ � 52.744°), 8582 unique (R int = 0.0552, R sigma = 0.0283) which were used in all calculations. The final R 1 was 0.1293 (I > 2σ(I)) and wR 2 was 0.3453 (all data).…”

“…H NMR (400 MHz, CDCl 3 ) δ 3.03 (dq, J = 7.3, 7.3 Hz, 8H), 1.52 (pentet, J = 7.3 Hz, 8H), 1.33 (sextet, J = 7.3 Hz, 8H), 0.91 (t, J = 7.3 Hz, 12H),1 H { 31 P} NMR (300 MHz, CDCl 3 ) δ 3.03 (m, 8H), 1.52 (pentet, J = 7.3 Hz, 8H), 1.33 (sextet, J = 7.3 Hz, 8H), 0.91 (t, J = 7.3 Hz, 12H),13 C NMR (101 MHz, CDCl 3 ) δ 52.55 (m), 34.22, 19.85, 14.05, 31 P NMR (162 MHz, CDCl 3 ) δ 81.48 (m), 31 P{ 1 H} NMR (162 MHz, CDCl 3 ) δ 81.48 (s), HRMS (APCI, [M + 1] + ): calc. 455.1555, expt.…”