More Like this

1. The Dialuminene Ar ^iPr8 AlAlAr ^iPr8 (Ar ^iPr8 =C ₆ H‐2,6‐(C ₆ H ₂ ‐2,4,6‐ ⁱ Pr ₃ ) ₂ ‐3,5‐ ⁱ Pr ₂ )

   https://doi.org/10.1002/ange.202412599  

   Lehmann, Annika; Queen, Joshua D; Roberts, Christopher J; Rissanen, Kari; Tuononen, Heikki M; Power, Philip P (December 2024, Angewandte Chemie)

   Abstract Careful analysis of the crystals formed in the reduction of Ar^iPr8AlI₂(Ar^iPr8=C₆H‐2,6‐(C₆H₂‐2,4,6‐ⁱPr₃)₂‐3,5‐ⁱPr₂) with sodium on sodium chloride showed them to contain the long sought‐after dialuminene Ar^iPr8AlAlAr^iPr8(1) that forms alongside the previously characterized alanediyl :AlAr^iPr8. The single crystal X‐ray structure of1revealed a nearly planar,trans‐bent C(ipso)AlAlC(ipso) core with an Al−Al distance of 2.648(2) Å. The molecular and electronic structure of1are consistent with an Al−Al double dative interaction augmented with diradical character and stabilized by dispersion interactions. Density functional theory calculations showed that the reactivity of :AlAr^iPr8with dihydrogen involves1, not :AlAr^iPr8, as the reactive species. In contrast, the reaction of :AlAr^iPr8with ethylene gave two products, the 1,4‐dialuminacyclohexane Ar^iPr8Al(C₂H₄)₂AlAr^iPr8(2) and the aluminacyclopentane Ar^iPr8Al(C₄H₈) (3), that can both form from the aluminacyclopropane intermediate Ar^iPr8Al(C₂H₄). Although the [2+2+2] cycloaddition of1with two equivalents of ethylene was also calculated to be exergonic, it is likely to be kinetically blocked by the numerous isopropyl substituents surrounding the Al−Al bond. Attempts to fine‐tune the steric bulk of the terphenyl ligand to allow stronger Al−Al bonding were unsuccessful, leading to the isolation of the sodium salt of a cyclotrialuminene, Na₂[AlAr^iPr6]₃(4), instead of Ar^iPr6AlAlAr^iPr6. 

   more » « less
2. Redox Studies of the Scandium Metallocene (C ₅ H ₂ ^t Bu ₃ ) ₂ Sc ^II Lead to a Terminal Side-On (N═N) ^2– Complex: [(C ₅ H ₂ ^t Bu ₃ ) ₂ Sc ^III (η ² -N ₂ )] ⁻

   https://doi.org/10.1021/jacs.5c00607  

   Queen, Joshua D; Rajabi, Ahmadreza; Ziller, Joseph W; Furche, Filipp; Evans, William J (April 2025, Journal of the American Chemical Society)
3. Branching Ratio for O + H ₃ ⁺ Forming OH ⁺ + H ₂ and H ₂ O ⁺ + H

   https://doi.org/10.3847/1538-4357/ac41ce  

   Hillenbrand, Pierre-Michel; Ruette, Nathalie de; Urbain, Xavier; Savin, Daniel W. (March 2022, The Astrophysical Journal)

   Abstract The gas-phase reaction of O + H 3 + has two exothermic product channels: OH + + H 2 and H 2 O + + H. In the present study, we analyze experimental data from a merged-beams measurement to derive thermal rate coefficients resolved by product channel for the temperature range from 10 to 1000 K. Published astrochemical models either ignore the second product channel or apply a temperature-independent branching ratio of 70% versus 30% for the formation of OH + + H 2 versus H 2 O + + H, respectively, which originates from a single experimental data point measured at 295 K. Our results are consistent with this data point, but show a branching ratio that varies with temperature reaching 58% versus 42% at 10 K. We provide recommended rate coefficients for the two product channels for two cases, one where the initial fine-structure population of the O( 3 P J ) reactant is in its J = 2 ground state and the other one where it is in thermal equilibrium. 

   more » « less
4. Helium Nanodroplet Infrared Spectroscopic Studies of CH ₄ ⁺ and ¹³ CH ₃ ⁺

   https://doi.org/10.1021/acs.jpca.4c06858  

   Singh, Amandeep; Allison, Sofia H; Azhagesan, Andrew_Abhisek A; Vilesov, Andrey F (December 2024, The Journal of Physical Chemistry A)
5. Comparison of two Mn ^IV Mn ^IV -bis-μ-oxo complexes {[Mn ^IV (N ₄ (6-Me-DPEN))] ₂ (μ-O) ₂ } ²⁺ and {[Mn ^IV (N ₄ (6-Me-DPPN))] ₂ (μ-O) ₂ } ²⁺

   https://doi.org/10.1107/S2056989020004557  

   Coggins, Michael K.; Downing, Alexandra N.; Kaminsky, Werner; Kovacs, Julie A. (July 2020, Acta Crystallographica Section E Crystallographic Communications)

   null (Ed.)

   The addition of tert -butyl hydroperoxide ( t BuOOH) to two structurally related Mn II complexes containing N,N -bis(6-methyl-2-pyridylmethyl)ethane-1,2-diamine (6-Me-DPEN) and N,N -bis(6-methyl-2-pyridylmethyl)propane-1,2-diamine (6-Me-DPPN) results in the formation of high-valent bis-oxo complexes, namely di-μ-oxido-bis{[ N , N -bis(6-methyl-2-pyridylmethyl)ethane-1,2-diamine]manganese(II)}( Mn — Mn ) bis(tetraphenylborate) dihydrate, [Mn(C 16 H 22 N 4 ) 2 O 2 ](C 24 H 20 B) 2 ·2H 2 O or {[Mn IV (N 4 (6-Me-DPEN))] 2 ( μ -O) 2 }(2BPh 4 )(2H 2 O) ( 1 ) and di-μ-oxido-bis{[ N , N -bis(6-methyl-2-pyridylmethyl)propane-1,3-diamine]manganese(II)}( Mn — Mn ) bis(tetraphenylborate) diethyl ether disolvate, [Mn(C 17 H 24 N 4 ) 2 O 2 ](C 24 H 20 B) 2 ·2C 4 H 10 O or {[Mn IV (N 4 (6-MeDPPN))] 2 ( μ -O) 2 }(2BPh 4 )(2Et 2 O) ( 2 ). Complexes 1 and 2 both contain the `diamond core' motif found previously in a number of iron, copper, and manganese high-valent bis-oxo compounds. The flexibility in the propyl linker in the ligand scaffold of 2 , as compared to that of the ethyl linker in 1 , results in more elongated Mn—N bonds, as one would expect. The Mn—Mn distances and Mn—O bond lengths support an Mn IV oxidation state assignment for the Mn ions in both 1 and 2 . The angles around the Mn centers are consistent with the local pseudo-octahedral geometry. 

   more » « less