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1. A Heterogeneous Palladium Catalyst for the Polymerization of Olefins Prepared by Halide Abstraction Using Surface R 3 Si + Species

   https://doi.org/10.1002/ange.202117279  

   Gao, Jiaxin ; Dorn, Rick W. ; Laurent, Guillaume P. ; Perras, Frédéric A. ; Rossini, Aaron J. ; Conley, Matthew P. ( March 2022 , Angewandte Chemie)

   The silylium‐like surface species [ⁱPr₃Si][(R^FO)₃Al−OSi≡)] activates (N^N)Pd(CH₃)Cl (N^N=Ar−N=CMeMeC=N−Ar, Ar=2,6‐bis(diphenylmethyl)‐4‐methylbenzene) by chloride ion abstraction to form [(N^N)Pd−CH₃][(R^FO)₃Al−OSi≡)] (1). A combination of FTIR, solid‐state NMR spectroscopy, and reactions with CO or vinyl chloride establish that1shows similar reactivity patterns as (N^N)Pd(CH₃)Cl activated with Na[B(Ar^F)₄]. Multinuclear¹³C{²⁷Al} RESPDOR and¹H{¹⁹F} S‐REDOR experiments are consistent with a weakly coordinated ion‐pair between (N^N)Pd−CH₃⁺and [(R^FO)₃Al−OSi≡)].1catalyzes the polymerization of ethylene with similar activities as [(N^N)Pd−CH₃]⁺in solution and incorporates up to 0.4 % methyl acrylate in copolymerization reactions.1produces polymers with significantly higher molecular weight than the solution catalyst, and generates the highest molecular weight polymers currently reported in copolymerization reactions of ethylene and methylacrylate.

    

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2. Organo‐Functionalized Lacunary Double Cubane‐Type Oxometallates: Synthesis, Structure, and Properties of [(M II Cl) 2 (V IV O) 2 {((HOCH 2 CH 2 )(H)N(CH 2 CH 2 O))(HN(CH 2 CH 2 O) 2 )} 2 ] (M=Co, Zn)

   https://doi.org/10.1002/chem.202301389  

   Shuaib, Damola T. ; Swenson, LaSalle ; Kaduk, James A. ; Chang, Tieyan ; Chen, Yu‐Sheng ; McNeely, James ; Khan, M. Ishaque ( October 2023 , Chemistry – A European Journal)

   Organofunctionalized tetranuclear clusters [(M^IICl)₂(V^IVO)₂{((HOCH₂CH₂)(H)N(CH₂CH₂O))(HN(CH₂CH₂O)₂)}₂] (1, M=Co,2: M=Zn) containing an unprecedented oxometallacyclic {M₂V₂Cl₂N₄O₈} (M=Co, Zn) framework have been prepared by solvothermal reactions. The new oxo‐alkoxide compounds were fully characterized by spectroscopic methods, magnetic susceptibility measurement, DFT and ab initio computational methods, and complete single‐crystal X‐ray diffraction structure analysis. The isostructural clusters are formed of edge‐sharing octahedral {VO₅N} and trigonal bipyramidal {MO₃NCl} units. Diethanolamine ligates the bimetallic lacunary double cubane core of1and2in an unusual two‐mode fashion, unobserved previously. In the crystalline state, the clusters of1and2are joined by hydrogen bonds to form a three‐dimensional network structure. Magnetic susceptibility data indicate weakly antiferromagnetic interactions between the vanadium centers [J_iso(V^IV−V^IV)=−5.4(1); −3.9(2) cm⁻¹], and inequivalent antiferromagnetic interactions between the cobalt and vanadium centers [J_iso(V^IV−Co^II)=−12.6 and −7.5 cm⁻¹] contained in1.

    

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3. A PCP Pincer Ligand for Coordination Polymers with Versatile Chemical Reactivity: Selective Activation of CO 2 Gas over CO Gas in the Solid State

   https://doi.org/10.1002/ange.201604730  

   He, Junpeng ; Waggoner, Nolan W. ; Dunning, Samuel G. ; Steiner, Alexander ; Lynch, Vincent M. ; Humphrey, Simon M. ( August 2016 , Angewandte Chemie)

   A tetra(carboxylated) PCP pincer ligand has been synthesized as a building block for porous coordination polymers (PCPs). The air‐ and moisture‐stable PCP metalloligands are rigid tetratopic linkers that are geometrically akin to ligands used in the synthesis of robust metal–organic frameworks (MOFs). Here, the design principle is demonstrated by cyclometalation with Pd^IICl and subsequent use of the metalloligand to prepare a crystalline 3D MOF by direct reaction with Co^IIions and structural resolution by single crystal X‐ray diffraction. The Pd−Cl groups inside the pores are accessible to post‐synthetic modifications that facilitate chemical reactions previously unobserved in MOFs: a Pd−CH₃activated material undergoes rapid insertion of CO₂gas to give Pd−OC(O)CH₃at 1 atm and 298 K. However, since the material is highly selective for the adsorption of CO₂over CO, a Pd−N₃modified version resists CO insertion under the same conditions.

    

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4. Role of curvature in acridone for 1O2 oxidation of a natural product homoallylic alcohol: A novel iso ‐hydroperoxide intermediate

   https://doi.org/10.1111/php.13843  

   Lapoot, Lloyd ; Jabeen, Shakeela ; Durantini, Andrés M. ; Greer, Alexander ( August 2023 , Photochemistry and Photobiology)

   A density functional theoretical (DFT) study is presented, implicating a¹O₂oxidation process to reach a dihydrobenzofuran from the reaction of the natural homoallylic alcohol, glycocitrine. Our results predict an interconversion between glycocitrine and aniso‐hydroperoxide intermediate [R(H)O⁺–O⁻] that provides a key path in the chemistry which then follows. Formations of allylic hydroperoxides are unlikely from a¹O₂‘ene’ reaction. Instead, the dihydrobenzofuran arises by¹O₂oxidation facilitated by a 16° curvature of the glycocitrine ring imposed by a pyramidalN‐methyl group. This curvature facilitates the formation of theiso‐hydroperoxide, which is analogous to theisospecies CH₂I⁺–I⁻and CHI₂⁺–I⁻formed by UV photolysis of CH₂I₂and CHI₃. Theiso‐hydroperoxide is also structurally reminiscent of carbonyl oxides (R₂C=O⁺–O⁻) formed in the reaction of carbenes and oxygen. Our DFT results point to intermolecular process, in which theiso‐hydroperoxide's fate relates to O‐transfer and H₂O dehydration reactions for new insight into the biosynthesis of dihydrobenzofuran natural products.

    

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5. A Nonheme Mononuclear {FeNO} 7 Complex that Produces N 2 O in the Absence of an Exogenous Reductant

   https://doi.org/10.1002/ange.202109062  

   Dey, Aniruddha ; Gordon, Jesse B. ; Albert, Therese ; Sabuncu, Sinan ; Siegler, Maxime A. ; MacMillan, Samantha N. ; Lancaster, Kyle M. ; Moënne‐Loccoz, Pierre ; Goldberg, David P. ( August 2021 , Angewandte Chemie)

   A new nonheme iron(II) complex, Fe^II(Me₃TACN)((OSi^Ph2)₂O) (1), is reported. Reaction of1with NO_(g)gives a stable mononitrosyl complex Fe(NO)(Me₃TACN)((OSi^Ph2)₂O) (2), which was characterized by Mössbauer (δ=0.52 mm s⁻¹, |ΔE_Q|=0.80 mm s⁻¹), EPR (S=3/2), resonance Raman (RR) and Fe K‐edge X‐ray absorption spectroscopies. The data show that2is an {FeNO}⁷complex with anS=3/2 spin ground state. The RR spectrum (λ_exc=458 nm) of2combined with isotopic labeling (¹⁵N,¹⁸O) reveals ν(N‐O)=1680 cm⁻¹, which is highly activated, and is a nearly identical match to that seen for the reactive mononitrosyl intermediate in the nonheme iron enzyme FDPnor (ν(NO)=1681 cm⁻¹). Complex2reacts rapidly with H₂O in THF to produce the N‐N coupled product N₂O, providing the first example of a mononuclear nonheme iron complex that is capable of converting NO to N₂O in the absence of an exogenous reductant.

    

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