A phosphorus-rich polymer as a homogeneous catalyst scavenger

© The Royal Society of Chemistry 2017. A soft polymer network prepared through a phosphane-ene reaction successfully sequestered Rh and Ru from hydrogenation and ring closing metathesis reactions, respectively. Scavenging effectively quenches catalytic activity and ultimately removes \u3e98% of the metal

Geometrically enforced donor-facilitated dehydrocoupling leading to an isolable arsanylidine-phosphorane

This work was made open access through funds from the RCUK open access block grant.A proximate Lewis basic group facilitates the mild dehydrogenative P–As intramolecular coupling in the phosphine-arsine peri-substituted acenaphthene 3 , affording thermally and hydrolytically stable arsanylidine-phosphorane 4 with a sterically accessible two-coordinate arsenic atom. The formation of 4 is thermoneutral due to the dehydrogenation being concerted with the donor coordination. Reaction of 4 with a limited amount of oxygen reveals arsinidene-like reactivity via formation of cyclooligoarsines, supporting the formulation of the bonding in 4 as base-stabilized arsinidene R3P→AsR.Publisher PDFPeer reviewe

Synthesis and Characterization of Primary Aluminum Parent Amides and Phosphides

The synthesis and characterization of the sterically crowded primary alanes (Ar^{<i>i</i>Pr₄}AlH₂)₂ (Ar^{<i>i</i>Pr₄} = C₆H₃-2,6­(C₆H₃-2,6-^<i>i</i>Pr₂)₂) and (Ar^{<i>i</i>Pr₈}AlH₂)₂ (Ar^{<i>i</i>Pr₈} = C₆H-2,6­(C₆H₂-2,4,6-^<i>i</i>Pr₆)₂-3,5-^<i>i</i>Pr₂) are described. They, along with their previously reported less-hindered analogue (Ar^Me₆AlH₂)₂ (Ar^Me₆ = C₆H₃-2,6­(C₆H₂-2,4,6-Me₃)₂), were reacted with ammonia to give the parent amido alanes {Ar^<i>x</i>Al­(H)­NH₂}₂ (Ar^<i>x</i> = Ar^Me₆, <b>1</b>; Ar^{<i>i</i>Pr₄}, <b>2</b>; Ar^{<i>i</i>Pr₈}, <b>3</b>), which are the first well-characterized hydride amido derivatives of aluminum and are relatively rare examples of parent aluminum amides. In contrast, the reaction of (Ar^Me₆AlH₂)₂ with phosphine yielded the structurally unique Al/P cage species {(Ar^Me₆Al)₃(μ-PH₂)₃(μ-PH)­PH₂} (<b>4</b>) as the major product and a smaller amount of {(Ar^Me₆Al)₄(μ-PH₂)₄(μ-PH)} (<b>5</b>) as a minor product. All compounds were characterized by NMR and IR spectroscopy, while compounds <b>2</b>–<b>5</b> were also characterized by X-ray crystallography

Synthesis and Characterization of Primary Aluminum Parent Amides and Phosphides

The synthesis and characterization of the sterically crowded primary alanes (Ar^{<i>i</i>Pr₄}AlH₂)₂ (Ar^{<i>i</i>Pr₄} = C₆H₃-2,6­(C₆H₃-2,6-^<i>i</i>Pr₂)₂) and (Ar^{<i>i</i>Pr₈}AlH₂)₂ (Ar^{<i>i</i>Pr₈} = C₆H-2,6­(C₆H₂-2,4,6-^<i>i</i>Pr₆)₂-3,5-^<i>i</i>Pr₂) are described. They, along with their previously reported less-hindered analogue (Ar^Me₆AlH₂)₂ (Ar^Me₆ = C₆H₃-2,6­(C₆H₂-2,4,6-Me₃)₂), were reacted with ammonia to give the parent amido alanes {Ar^<i>x</i>Al­(H)­NH₂}₂ (Ar^<i>x</i> = Ar^Me₆, <b>1</b>; Ar^{<i>i</i>Pr₄}, <b>2</b>; Ar^{<i>i</i>Pr₈}, <b>3</b>), which are the first well-characterized hydride amido derivatives of aluminum and are relatively rare examples of parent aluminum amides. In contrast, the reaction of (Ar^Me₆AlH₂)₂ with phosphine yielded the structurally unique Al/P cage species {(Ar^Me₆Al)₃(μ-PH₂)₃(μ-PH)­PH₂} (<b>4</b>) as the major product and a smaller amount of {(Ar^Me₆Al)₄(μ-PH₂)₄(μ-PH)} (<b>5</b>) as a minor product. All compounds were characterized by NMR and IR spectroscopy, while compounds <b>2</b>–<b>5</b> were also characterized by X-ray crystallography

Transition Metal Functionalization of P₄ Using a Diarylgermylene Anchor

The manipulation of white phosphorus (P₄) has been a long-standing challenge for chemists. While the holy grail remains at finding a method to catalytically activate and functionalize P₄ to yield new organophosphorus compounds, fundamental research lies in developing procedures to control the reactivity of elemental phosphorus. In this work, Lewis acidic transition metal moieties M­(CO)₅ (M = Cr, Mo, W) and AuCl react with P₄ derivatized with a low valent germanium compound. For both M­(CO)₅ and AuCl, bis-functionalized products can be formed; however the monosubstituted derivatives are found to be more stable, and the decomposition can be monitored by ³¹P­{¹H} NMR spectroscopy. The selective reactivity of white phosphorus, once a P–P bond has been activated, is a key step in yielding new organophosphorus compounds

Reduced PD-1 expression on circulating CXCR5+ and CXCR5- FOXP3+ Treg cells marks type 1 diabetes initiation in children

Autoantibodies (AAbs) are a hallmark of Type 1 diabetes (T1D). Alterations in the frequency and phenotype of follicular helper (Tfh) T cells have been previously documented in patients with type 1 diabetes (T1D), but the contribution of follicular Treg cells, which are responsible for suppressing AAb development, is less clear. Here, we investigated the frequency and activation status of follicular (CXCR5+) and CXCR5- Treg cells in the blood of children with new onset T1D and children with risk for developing T1D (AAb-positive) and compared them to AAb-negative controls. Blood CXCR5+ and CXCR5- Treg cells were higher in frequency children with new onset T1D and expressed reduced amounts of PD-1 as compared to controls. Interestingly, the proportion of circulating FOXP3+ Tregs expressing PD-1 was also reduced in AAb-positive at-risk children as compared to controls, suggesting its potential use as a biomarker of disease initiation