An untetheredC_3v-symmetric triarylphosphine oxide locked by intermolecular hydrogen bonding

Abstract

A C3v-symmetric triarylphosphine oxide locked into conformation by H-bonding and displaying an extended MOF-like solid-state structure is reported.

Redox-Controlled Reactivity at Boron: Parallels to Frustrated Lewis/Radical Pair Chemistry

“…Our group has been exploring new reactivity at main-group centers by tethering these to redox-active metal centers, such as V or Fe. − In a recent contribution, we uncovered how a typically unreactive P V O bond tethered to a neighboring V V center in the complexes (Ph 2 N) 3 VN–P­(O)­Ar 2 (Ar = Ph, C 6 F 5 ) can engage in H atom (H·) or silyl group (Me 3 Si·) transfer chemistry, resulting in the proposed protonation or isolated silylation of the P V O bond, respectively, with the concurrent reduction of V V to V IV . Similar reactivity was not observed in related all-main-group model compounds (ex.…”

Two-dimensional metal–organic layers constructed from Hf6/Hf12-oxo clusters and a trigonal pyramidal phosphine oxide ligand

“…To expand the structural diversity of Zr/Hf MOLs, herein, we investigated a trigonal pyramidal shape ligand tris(4-carboxylphenyl)phosphine oxide (TPO), 22 which is quite different from those used in the previous MOLs. Based on related reports of the MOF crystal structures of this ligand, we envisioned that it is highly feasible to obtain MOL materials.…”

“…Currently, reported Zr/Hf-based MOL structures include the kgd lattice constructed from 6-connected SBUs and planar trigonal ligands, 2,17 the sql lattice constructed from 4-connected SBUs and planar 4-connected ligands, 18,19 and the hxl lattice constructed from 6-connected SBUs and ditopic ligands. 20,21 To expand the structural diversity of Zr/Hf MOLs, herein, we investigated a trigonal pyramidal shape ligand tris(4-carboxylphenyl)phosphine oxide (TPO), 22 which is quite different from those used in the previous MOLs. Based on related reports of the MOF crystal structures of this ligand, we envisioned that it is highly feasible to obtain MOL materials.…”

“…S1-4 †) by facile oxidation of commercially available tris(4-methylphenyl)phosphine. 22,26 It is worth noting that we can replace TPO in the MOL with the reduced tris(4-carboxylphenyl)phosphine (TPP) ligands 27,28 without the oxygen on the PvO to release free-phosphine sites. This adds to the chemical diversity of the coordinating sites on the MOL for supporting low-coordination metals.…”

Unusual C–H Bond Activation and C(sp3)–C(sp3) Bond Formation at an Fe(II) Bis(amide) Carbene Complex

“…C–H bond activation is an attractive avenue for the transformation of inexpensive and abundant feedstocks into value-added commodity chemicals. At the industrial level, for example, the DuPont “butox” process catalyzes the partial oxidation of n -butane to maleic anhydride via a heterogeneous vanadium phosphorus oxide (VPO) catalyst. − While most research assigned the vanadyl (VO) centers as the reactive sites for butane C–H bond activation, recent DFT studies suggest that the catalyst support PO bonds, tethered to neighboring vanadyls, may instead be responsible, reacting by a cooperative proton-coupled electron transfer (PCET) mechanism with neighboring high-valent V centers (Scheme a). − In order to probe this possible new main-group mediated C–H bond functionalization chemistry, we have recently reported a suite of molecular mono- or multimetallic VPO model complexes of the general formula, (R x V n –L) y P­(O)­Ar (3– y ) (R x = Cp 2 , n = +3, L = O, y = 1, 2, and 3, Ar = Ph; R x = Cp 2 , n = +3, L = O­(O)­C­(C 6 H 4 ), y = 1 and 3, Ar = Ph; R x = (Ph 2 N) 3 , n = +5, L = N, y = 1, Ar = Ph, C 6 F 5 ) (Cp = η 5 -C 5 H 5 ). − All of these molecules bear a central M–L–EO framework where M is the metal redox reservoir (e.g., V), L is a resonance linker atom (e.g., O and N) or fragment (e.g., aryl), and E is the main group center (e.g., P). Using the high-valent (Ph 2 N) 3 VN–P­(O)­Ar 2 (Ar = Ph or C 6 F 5 ) complexes, we found convincing evidence supporting this proposed PCET pathway using an H atom donor, as well as an H atom surrogate in the form of a TMS • donor (TMS = Me 3 Si) (Scheme a) .…”