More Like this

1. Resolving the contrasting leaf hydraulic adaptation of C₃ and C₄ grasses

   https://doi.org/10.1111/nph.20341  

   Baird, Alec_S; Taylor, Samuel_H; Pasquet‐Kok, Jessica; Vuong, Christine; Zhang, Yu; Watcharamongkol, Teera; Cochard, Hervé; Scoffoni, Christine; Edwards, Erika_J; Osborne, Colin_P; et al (January 2025, New Phytologist)

   Summary Grasses are exceptionally productive, yet their hydraulic adaptation is paradoxical. Among C₃grasses, a high photosynthetic rate (A_area) may depend on higher vein density (D_v) and hydraulic conductance (K_leaf). However, the higherD_vof C₄grasses suggests a hydraulic surplus, given their reduced need for highK_leafresulting from lower stomatal conductance (g_s).Combining hydraulic and photosynthetic physiological data for diverse common garden C₃and C₄species with data for 332 species from the published literature, and mechanistic modeling, we validated a framework for linkages of photosynthesis with hydraulic transport, anatomy, and adaptation to aridity.C₃and C₄grasses had similarK_leafin our common garden, but C₄grasses had higherK_leafthan C₃species in our meta‐analysis. Variation inK_leafdepended on outside‐xylem pathways. C₄grasses have highK_leaf : g_s, which modeling shows is essential to achieve their photosynthetic advantage.Across C₃grasses, higherA_areawas associated with higherK_leaf, and adaptation to aridity, whereas for C₄species, adaptation to aridity was associated with higherK_leaf : g_s. These associations are consistent with adaptation for stress avoidance.Hydraulic traits are a critical element of evolutionary and ecological success in C₃and C₄grasses and are crucial avenues for crop design and ecological forecasting. 

   more » « less
2. Influence of Aryl Substituents on the Alignment of Ligands in the Dirhodium Tetrakis(1,2,2‐Triarylcyclopropane‐ carboxylate) Catalysts

   https://doi.org/10.1002/cctc.202001206  

   Ren, Zhi; Musaev, Djamaladdin_G; Davies, Huw_M_L (September 2020, ChemCatChem)

   Abstract Computational studies revealed that dirhodium tetrakis(1,2,2‐triarylcyclopropanecarboxylate) (Rh₂(TPCP)₄) catalysts adopt distinctive high symmetry orientations, which are dependent on the nature of the aryl substitution pattern. The parent catalyst, Rh₂(TPCP)₄, and those with ap‐substituent at the C1 aryl, such as Rh₂(p‐BrTPCP)₄and Rh₂(p‐PhTPCP)₄, adopt aC₂‐symmetric structure. Rh₂(3,5‐di(p‐^tBuC₆H₄)TPCP)₄, 3,5‐disubstituted at the C1 aryl, adopts aD₂‐symmetric structure, whereas catalysts with ano‐substituent at the C1 aryl, such as Rh₂(o‐Cl‐5‐BrTPCP)_4,adopt aC₄‐symmetric structure. 

   more » « less
3. Immobilized phosphate‐binding protein can effectively discriminate against arsenate during phosphate adsorption and recovery

   https://doi.org/10.1002/wer.1498  

   Venkiteshwaran, Kaushik; Wells, Erin; Mayer, Brooke K. (December 2020, Water Environment Research)

   Abstract There is a strong impetus to establish a circular phosphorus economy by securing internally renewable phosphate (P_i) resources for use as agricultural fertilizers. Reversible P_iadsorption technologies such as ion exchange can remove and recover P_ifrom water/wastewater for reuse. However, existing reversible adsorbents cannot effectively discriminate against arsenate (As(V)) due to the similarity between As(V) and P_ichemical structure. If As(V) is co‐recovered with P_i, the value of the recovered products for agricultural reuse is low. The objective of this study was to construct an immobilized phosphate‐binding protein (PBP)‐based P_iremoval and recovery system and analyze its selectivity for P_iadsorption in the presence of As(V). A range of conditions was tested, including independent, sequential, and simultaneous exposure of the two oxyanions to immobilized PBP (PBP resin). The purity of the recovered P_iproduct was assessed after inducing controlled desorption of the adsorbed oxyanions at high pH (pH 12.5). P_iconstituted more than 97% of the adsorbed oxyanions in the recovered product, even when As(V) was initially present at twofold higher concentrations than P_i. Therefore, PBP resin has potential to selectively remove P_i, as well as release high‐purity P_ifree of As(V) contamination suitable for subsequent agricultural reuse. Practitioner pointsExisting reversible phosphate (P_i) adsorbents cannot effectively discriminate against arsenate (As(V)) due to the similarity in their chemical structure.Co‐recovery of As(V) with P_ican reduce the recovered product's reuse as a fertilizer.An immobilized phosphate‐binding protein (PBP)‐based system can be highly selective for P_ieven in the presence of As(V).P_iconstituted more than 97% of the recovered product, even when As(V) was present at 2‐fold higher concentrations than P_i.Immobilized PBP offers advantages over existing P_iadsorbents by providing high‐purity P_iproducts free of As(V) contamination for reuse. 

   more » « less
4. Identification of a prismatic P3N3 molecule formed from electron irradiated phosphine-nitrogen ices

   https://doi.org/10.1038/s41467-021-25775-1  

   Zhu, Cheng; Eckhardt, André K.; Chandra, Sankhabrata; Turner, Andrew M.; Schreiner, Peter R.; Kaiser, Ralf I. (September 2021, Nature Communications)

   Abstract Polyhedral nitrogen containing molecules such as prismatic P₃N₃- a hitherto elusive isovalent species of prismane (C₆H₆) - have attracted particular attention from the theoretical, physical, and synthetic chemistry communities. Here we report on the preparation of prismatic P₃N₃[1,2,3-triaza-4,5,6-triphosphatetracyclo[2.2.0.0^2,6.0^3,5]hexane] by exposing phosphine (PH₃) and nitrogen (N₂) ice mixtures to energetic electrons. Prismatic P₃N₃was detected in the gas phase and discriminated from its isomers utilizing isomer selective, tunable soft photoionization reflectron time-of-flight mass spectrometry during sublimation of the ices along with an isomer-selective photochemical processing converting prismatic P₃N₃to 1,2,4-triaza-3,5,6-triphosphabicyclo[2.2.0]hexa-2,5-diene (P₃N₃). In prismatic P₃N₃, the P–P, P–N, and N–N bonds are lengthened compared to those in, e.g., diphosphine (P₂H₄), di-anthracene stabilized phosphorus mononitride (PN), and hydrazine (N₂H₄), by typically 0.03–0.10 Å.  These findings advance our fundamental understanding of the chemical bonding of poly-nitrogen and poly-phosphorus systems and reveal a versatile pathway to produce exotic, ring-strained cage molecules. 

   more » « less
5. Synthesis and characterization of modular polyphosphonate homopolymers and copolymers

   https://doi.org/10.1002/pol.20200066  

   Totsch, Timothy R.; Stanford, Victoria L.; Klep, Oleksander; Burdette, Mary K.; Grant, Benjamin; Foulger, Stephen H.; Gray, Gary M. (June 2020, Journal of Polymer Science)

   Abstract Linear polyphosphonates with the generic formula –[P(Ph)(X)OR′O]_n– (X = S or Se) have been synthesized by polycondensations of P(Ph)(NEt₂)₂and a diol (HOR′OH = 1,4‐cyclohexanedimethanol, 1,4‐benzenedimethanol, tetraethylene glycol, or 1,12‐dodecanediol) followed by reaction with a chalcogen. Random copolymers have been synthesized by polycondensations of P(Ph)(NEt₂)₂and mixture of two of the diols in a 2:1:1 mol ratio followed by reaction with a chalcogen. Block copolymers with the generic formula –[P(Ph)(X)OR′O]_(x + 2)–[P(Ph)(X)OR′O]_(x + 3)– (X = S or Se) have been synthesized by the polycondensations of Et₂N[P(Ph)(X)OR′O]_(x + 2)P(Ph)NEt₂oligomers with HOR′O[P(Ph)(X)OR′O]_(x + 3)H oligomers followed by reaction with a chalcogen. The Et₂N[P(Ph)(X)OR′O]_(x + 2)P(Ph)NEt₂oligomers are prepared by the reaction of an excess of P(Ph)(NEt₂)₂with a diol while the HOR′O[P(Ph)(X)OR′O]_(x + 3)H oligomers are prepared by the reaction of P(Ph)(NEt₂)₂with an excess of the diol. In each case the excess, x is the same and determines the average block sizes. All of the polymers were characterized using¹H,¹³C{¹H}, and³¹P{¹H} NMR spectroscopy, TGA, DSC, and SEC.³¹P{¹H} NMR spectroscopy demonstrates that the random and block copolymers have the expected arrangements of monomers and, in the case of block copolymers, verifies the block sizes. All polymers are thermally stable up to ~300°C, and the arrangements of monomers in the copolymers (block vs. random) affect their degradation temperatures andT_gprofiles. The polymers have weight average MWs of up to 3.8 × 10⁴ Da. 

   more » « less