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1. Electronic Structure of trans‐ [V II Cl 2 (E(CH 3 ) 2 CH 2 CH 2 E(CH 3 ) 2 ) 2 ], E=N, P

   https://doi.org/10.1002/ejic.202400395  

   Jafari, Mehrafshan G ; Zolnhofer, Eva M ; Fehn, Dominik ; Heinemann, Frank W ; Opalade, Adedamola A ; Carroll, Patrick J ; Meyer, Karsten ; Krzystek, J ; Ozarowski, Andrew ; Mindiola, Daniel J ; et al ( November 2024 , European Journal of Inorganic Chemistry)

   Coordination complexes of general formulatrans‐[MX₂(R₂ECH₂CH₂ER₂)₂] (M^II=Ti, V, Cr, Mn; E=N or P; R=alkyl or aryl) are a cornerstone of coordination and organometallic chemistry. We investigate the electronic properties of two such complexes,trans‐[VCl₂(tmeda)₂] andtrans‐[VCl₂(dmpe)₂], which thus representtrans‐[MX₂(R₂ECH₂CH₂ER₂)₂] where M=V, X=Cl, R=Me and E=N (tmeda) and P (dmpe). These V^IIcomplexes haveS=3/2 ground states, as expected for octahedral d³. Their tetragonal distortion leads to zero‐field splitting (zfs) that is modest in magnitude (D≈0.3 cm⁻¹) relative to analogousS=1 Ti^IIand Cr^IIcomplexes. This parameter was determined from conventional EPR spectroscopy, but more effectively from high‐frequency and ‐field EPR (HFEPR) that determined the sign ofDas negative for the diamine complex, but positive for the diphosphine, which information had not been known for anytrans‐[VX₂(R₂ECH₂CH₂ER₂)₂] systems. The ligand‐field parameters oftrans‐[VCl₂(tmeda)₂] andtrans‐[VCl₂(dmpe)₂] are obtained using both classical theory andab initioquantum chemical theory. The results shed light not only on the electronic structure of V^IIin this environment, but also on differences between N and P donor ligands, a key comparison in coordination chemistry.

    

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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 Mechanistic Study on the Formation of Acetone (CH 3 COCH 3 ), Propanal (CH 3 CH 2 CHO), Propylene Oxide (c-CH 3 CHOCH 2 ) along with Their Propenol Enols (CH 3 CHCHOH/CH 3 C(OH)CH 2 ) in Interstellar Analog Ices

   https://doi.org/10.3847/1538-4357/ac8c92  

   Singh, Santosh K. ; Fabian Kleimeier, N. ; Eckhardt, André K. ; Kaiser, Ralf I. ( December 2022 , The Astrophysical Journal)

   Carbonyl-bearing complex organic molecules (COMs) in the interstellar medium (ISM) are of significant importance due to their role as potential precursors to biomolecules. Simple aldehydes and ketones like acetaldehyde, acetone, and propanal have been recognized as fundamental molecular building blocks and tracers of chemical processes involved in the formation of distinct COMs in molecular clouds and star-forming regions. Although previous laboratory simulation experiments and modeling established the potential formation pathways of interstellar acetaldehyde and propanal, the underlying formation routes to the simplest ketone—acetone—in the ISM are still elusive. Herein, we performed a systematic study to unravel the synthesis of acetone, its propanal and propylene oxide isomers, as well as the propenol tautomers in interstellar analog ices composed of methane and acetaldehyde along with isotopic-substitution studies to trace the reaction pathways of the reactive intermediates. Chemical processes in the ices were triggered at 5.0 K upon exposure to proxies of Galactic cosmic rays in the form of energetic electrons. The products were detected isomer-selectively via vacuum ultraviolet (VUV) photoionization reflectron time-of-flight mass spectrometry. In our experiments, the branching ratio of acetone (CH₃COCH₃):propylene oxide (c-CH₃CHOCH₂):propanal (CH₃CH₂CHO) was determined to be (4.82 ± 0.05):(2.86 ± 0.13):1. The radical–radical recombination reaction leading to acetone emerged as the dominant channel. The propenols appeared only at a higher radiation dose via keto–enol tautomerization. The current study provides mechanistic information on the fundamental nonequilibrium pathways that may be responsible for the formation of acetone and its (enol) isomers inside the interstellar icy grains.

    

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4. Raman spectral behavior of N 2 , CO 2 , and CH 4 in N 2 –CO 2 –CH 4 gas mixtures from 22°C to 200°C and 10 to 500 bars, with application to other gas mixtures

   https://doi.org/10.1002/jrs.6033  

   Sublett, Jr, D. Matthew ; Sendula, Eszter ; Lamadrid, Hector M. ; Steele‐MacInnis, Matthew ; Spiekermann, Georg ; Bodnar, Robert J. ( November 2020 , Journal of Raman Spectroscopy)

   The Raman spectral behavior of N₂, CO₂, and CH₄in ternary N₂–CO₂–CH₄mixtures was studied from 22°C to 200°C and 10 to 500 bars. The peak position of N₂in all mixtures is located at lower wavenumbers compared with pure N₂at the same pressure (P)–temperature (T) (PT) conditions. The Fermi diad splitting in CO₂is greater in the pure system than in the mixtures, and the Fermi diad splitting increases in the mixtures as CO₂concentration increases at constantPandT. The peak position of CH₄in the mixtures is shifted to higher wavenumbers compared with pure CH₄at the samePTconditions. However, the relationship between peak position and CH₄mole fraction is more complicated compared with the trends observed with N₂and CO₂. The relative order of the peak position isotherms of CH₄and N₂in the mixtures in pressure–peak position space mimics trends in the molar volume of the mixtures in pressure–molar volume space. Relationships between the direction of peak shift of individual components in the mixtures, the relative molar volumes of the mixtures, and the attraction and repulsion forces between molecules are developed. Additionally, the relationship between the peak position of N₂in ternary N₂–CO₂–CH₄mixtures with pressure is extended to other N₂‐bearing systems to assess similarities in the Raman spectral behavior of N₂in various systems.

    

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5. Hydrogenation reactions catalyzed by HN(CH 2 CH 2 PR 2 ) 2 -ligated copper complexes

   https://doi.org/10.1039/d1qi00776a  

   Ekanayake, Dewmi A. ; Chakraborty, Arundhoti ; Krause, Jeanette A. ; Guan, Hairong ( October 2021 , Inorganic Chemistry Frontiers)

   null (Ed.)

   HN(CH 2 CH 2 PR 2 ) 2 -ligated copper borohydride complexes, ( R PN H P)Cu(BH 4 ) (R = i Pr, Cy, t Bu), which can be prepared from ( R PN H P)CuBr and NaBH 4 , are capable of catalyzing the hydrogenation of aldehydes in an alcoholic solvent. More active hydrogenation catalysts are ( R PN H P)CuBr mixed with KO t Bu, allowing various aldehydes and ketones to be efficiently reduced to alcohols except those bearing a nitro, N -unprotected pyrrole, pyridine, or an ester group, or those prone to aldol condensation ( e.g. , 1-heptanal). Modifying the catalyst structure by replacing the NH group in ( i Pr PN H P)CuBr with an NMe group results in an inferior catalyst but preserves some catalytic activity. The hexanuclear copper hydride cluster, ( i Pr PN H P) 3 Cu 6 H 6 , is also competent in catalyzing the hydrogenation of aldehydes such as benzaldehyde and N -methyl-2-pyrrolecarboxaldehyde, albeit accompanied by decomposition pathways. The catalytic performance can be enhanced through the addition of a strong base or i Pr PN H P. The three catalytic systems likely share the same catalytically active species, which is proposed to be a mononuclear copper hydride ( R PN H P)CuH with the NH group bound to copper. 

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