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1. A Contiguous Tricyclic [P ₆ ] ^2– Framework Spanning Across Two Vanadium(III) Centers

   https://doi.org/10.1021/acs.organomet.2c00638  

   Senthil, Shuruthi; Gau, Michael R.; Mindiola, Daniel J. (February 2023, Organometallics)

   Paul Chirik (Ed.)

   The complex [(BDI)VCl(N{SiMe3}2)] (1) (BDI– = [ArNC(CH3)]2CH, Ar = 2,6-iPr2C6H3), a precursor readily prepared from metathesis of [(BDI)VCl2] and Na[N{SiMe3}2], can be reduced with Na/NaCl in the presence of white P4 to form a dinuclear species containing two VIII centers bridged by a tricyclic [P6]2– scaffold, namely, [(BDI)V(N{SiMe3}2)]2(μ-η1:η1-P6) (2). Coordination of [P6]2– involves a unique chairlike μ-η1:η1 binding mode with a contiguous tricyclic hexaphosphorus unit bridging across the two V centers. Complexes 1 and 2 have been structurally characterized, and a pathway toward the formation of the chairlike tricyclic [P6]2– scaffold in 2 is proposed. 

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2. Structure and magnetic characterization of some bicompartmental [N ₆ O ₂ ] divalent metal( ii ) complexes using bis(phenolato) ligands bearing two pendant bis(pyridyl) amine arms

   https://doi.org/10.1039/d3nj02380j  

   Mautner, Franz A.; Fischer, Roland C.; Torvisco, Ana; Nakashima, Kai; Handa, Makoto; Mikuriya, Masahiro; Salem, Nahed M.; Overby, Gabriel J.; Maier, Madison R.; Louka, Febee R.; et al (August 2023, New Journal of Chemistry)

   Reactions of the bicompartmental bis(phenolato) compound 6,6′-methylenebis(2-((bis(pyridin-2-ylmethyl)amino)methyl)-4-chlorophenol)hemihydrate (H 2 L ½H 2 O) with 3d metal( ii ) ions afforded novel fully structurally characterized bridged acetato dinuclear complexes [Mn 2 (HL)(μ 1,2 -OAc) 2 ]PF 6 (1) [Zn 2 (HL)(μ 1,2 -OAc)(H 2 O) 0.75 (MeOH) 0.25 ](PF 6 ) 2 ·0.45(H 2 O) (5) and [Cd 2 (HL)(μ 1,1,2 -OAc)(OAc)(H 2 O)]PF 6 ·H 2 O (6) as well as the polymeric bridged-azido tetranuclear catena -[Cu 4 (HL) 2 (μ 1,1 -N 3 ) 2 (μ 1,3 -N 3 ) 2 ](NO 3 ) 2 ·5H 2 O (4). The complex [Cu 4 (HL) 2 (ClO 4 ) 3 (H 2 O) 5 ](ClO 4 ) 3 ·5H 2 O (2) was partially characterized. In addition, three more dinuclear complexes [Cu 2 (H 2 L)(NO 3 ) 2 (H 2 O) 2 ](NO 3 ) 2 (3), [Cu 2 (HL)(OAc)(CH 3 OH)](PF 6 ) 2 (7) and [Cu 2 (HL)(NCS) 2 ]NO 3 ·2H 2 O (8) were also isolated. All complexes were characterized by CHN elemental analysis, IR and UV-Vis spectroscopy, ESI-MS, conductivity measurements and X-ray single crystal crystallography for compounds 1, 4, 5 and 6, where the bis(phenolato) ligand displayed different deprotonation (H 2 L, HL − and L 2− ). The magnetic susceptibility measurements over the temperature range 2–300 K revealed very weak antiferromagnetic coupling in dimanganese( ii ) 1 ( J = −1.64(1) cm −1 ) and almost negligible magnetic interaction in dicopper( ii ) 2 ( J = 0(3) cm −1 ). In the azido catena -[Cu 4 (HL) 2 (μ 1,1 -N 3 ) 2 (μ 1,3 -N 3 ) 2 ](NO 3 ) 2 ·5H 2 O (4) complex, the J value of −133(3) cm −1 was obtained upon moderate-to-strong antiferromagnetic coupling through the di-μ 1,3 -N 3 -bridged dicopper( ii ) unit with no magnetic interaction between the two copper( ii ) ions in the di-μ 1,1 -N 3 -bridged unit. 

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3. Sulfur Vacancy Related Optical Transitions in Graded Alloys of Mo _x W _1‐x S ₂ Monolayers

   https://doi.org/10.1002/adom.202302326  

   Ghafariasl, Mahdi; Zhang, Tianyi; Ward, Zachary_D; Zhou, Da; Sanchez, David; Swaminathan, Venkataraman; Terrones, Humberto; Terrones, Mauricio; Abate, Yohannes (February 2024, Advanced Optical Materials)

   Abstract Engineering electronic bandgaps is crucial for applications in information technology, sensing, and renewable energy. Transition metal dichalcogenides (TMDCs) offer a versatile platform for bandgap modulation through alloying, doping, and heterostructure formation. Here, the synthesis of a 2D Mo_xW_1‐xS₂graded alloy is reported, featuring a Mo‐rich center that transitions to W‐rich edges, achieving a tunable bandgap of 1.85 to 1.95 eV when moving from the center to the edge of the flake. Aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy showed the presence of sulfur monovacancy, V_S, whose concentration varied across the graded Mo_xW_1‐xS₂layer as a function of Mo content with the highest value in the Mo‐rich center region. Optical spectroscopy measurements supported by ab initio calculations reveal a doublet electronic state of V_S, which is split due to the spin‐orbit interaction, with energy levels close to the conduction band or deep in the bandgap depending on whether the vacancy is surrounded by W atoms or Mo atoms. This unique electronic configuration of V_Sin the alloy gave rise to four spin‐allowed optical transitions between the V_Slevels and the valence bands. The study demonstrates the potential of defect and optical engineering in 2D monolayers for advanced device applications. 

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4. Lefschetz Theory for Exterior Algebras and Fermionic Diagonal Coinvariants

   https://doi.org/10.1093/imrn/rnaa203  

   Kim, Jongwon; Rhoades, Brendon (August 2020, International Mathematics Research Notices)

   null (Ed.)

   Abstract Let $$W$$ be an irreducible complex reflection group acting on its reflection representation $$V$$. We consider the doubly graded action of $$W$$ on the exterior algebra $$\wedge (V \oplus V^*)$$ as well as its quotient $$DR_W:= \wedge (V \oplus V^*)/ \langle \wedge (V \oplus V^*)^{W}_+ \rangle $$ by the ideal generated by its homogeneous $$W$$-invariants with vanishing constant term. We describe the bigraded isomorphism type of $$DR_W$$; when $$W = {{\mathfrak{S}}}_n$$ is the symmetric group, the answer is a difference of Kronecker products of hook-shaped $${{\mathfrak{S}}}_n$$-modules. We relate the Hilbert series of $$DR_W$$ to the (type A) Catalan and Narayana numbers and describe a standard monomial basis of $$DR_W$$ using a variant of Motzkin paths. Our methods are type-uniform and involve a Lefschetz-like theory, which applies to the exterior algebra $$\wedge (V \oplus V^*)$$. 

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5. Comparative performance of Fe‐ MO_x / SiO₂ (M = V, Mn, Co, Ni, Cu, Mo) and FeO_x / SiO₂ catalysts in reductive liquefaction of switchgrass in ethanol

   https://doi.org/10.1002/bbb.2720  

   Amarasekara, Ananda S; Morales, Gabriel Murillo; Kommalapati, Raghava R (March 2025, Biofuels, Bioproducts and Biorefining)

   Abstract The catalytic hydrothermal liquefaction of biomass under a hydrogen atmosphere is a promising technology to produce stable biocrude oil as a sustainable alternative to petroleum crude. A series of iron‐based non‐noble mix metal‐oxide‐on‐silica catalysts were evaluated to mimic the natural transformation that may have led to the conversion of terrestrial biomass to fossilized fuels. Switchgrass powder was liquefied to a stable bio‐oil with a 71.2% yield by using FeO_x/SiO₂catalyst in ethanol under a 5.5 MPa hydrogen atmosphere at 210 °C. The use of Fe‐MO_x/SiO₂(M = V, Mn, Co, Ni, Cu and Mo) type bimetallic oxide catalysts instead of FeO_x/SiO₂can produce improvements in liquefaction yields by using Mn, Co, Ni, and Cu as the second metal. The highest liquefaction yield of 78.8% was observed with the Fe‐CuO_x/SiO₂catalyst. Liquefaction oils were formed that were composed of complex mixtures of C6‐C12 alcohols, esters, aldehydes, and phenols. The lignin products:holocellulose products ratio changed in the range 0.35 to 0.15 and the composition of oils changed significantly with the use of mixed metal oxides in place of single metal FeO_x/SiO₂The most effective catalyst, Fe‐CuO_x/SiO₂could be reused in five cycles with a small loss in liquefaction yield from 78.8% to 70.0% after four reuse cycles and after regeneration of the catalyst at 500 °C for 3 h in air. 

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