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1. CO 2 Capture by 2-(Methylamino)pyridine Ligated Aluminum Alkyl Complexes:

   https://doi.org/10.1002/ejic.202000437  

   Yokley, Timothy W. ; Tupkar, Hrishikesh ; Schley, Nathan D. ; DeYonker, Nathan J. ; Brewster, Timothy P. ( May 2020 , European Journal of Inorganic Chemistry)

   A set of novel, easily synthesized aluminum complexes, Al(κ2-N,N-2-(methylamino)pyridine)2R (R = Et, iBu) are reported. When subjected to 1 atm of CO2 pressure, each hemilabile pyridine arm dissociates and facilitates cooperative activation of the CO2 substrate reminiscent of a Frustrated Lewis Pair. This reaction has limited precedent for Al/N based Lewis Pair systems, and this is the first system readily shown to sequester multiple equivalents of CO2 per aluminum center. The ethyl variant then reacts further, inserting a third equivalent of CO2 into the aluminum alkyl to generate an aluminum carboxylate. Examples of this type of reactivity are rare under thermal conditions. A joint experimental/computational study validates the proposed reaction mechanism. 

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2. Platinum( ii ) alkyl complexes of chelating dibridgehead diphosphines P((CH 2 ) n ) 3 P ( n = 14, 18, 22); facile cis / trans isomerizations interconverting gyroscope and parachute like adducts

   https://doi.org/10.1039/D1DT02321G  

   Zhu, Yun ; Ehnbom, Andreas ; Fiedler, Tobias ; Shu, Yi ; Bhuvanesh, Nattamai ; Hall, Michael B. ; Gladysz, John A. ( September 2021 , Dalton Transactions)

   The gyroscope like dichloride complexes trans -Pt(Cl) 2 (P((CH 2 ) n ) 3 P) ( trans -2; n = c, 14; e, 18; g, 22) and MeLi (2 equiv.) react to yield the parachute like dimethyl complexes cis -Pt(Me) 2 (P((CH 2 ) n ) 3 P) ( cis -4c,e,g, 70–91%). HCl (1 equiv.) and cis -4c react to give cis -Pt(Cl)(Me)(P((CH 2 ) 14 ) 3 P) ( cis -5c, 83%), which upon stirring with silica gel or crystallization affords trans -5c (89%). Similar reactions of HCl and cis -4e,g give cis / trans -5e,g mixtures that upon stirring with silica gel yield trans -5e,g. A parallel sequence with trans -2c/EtLi gives cis -Pt(Et) 2 (P((CH 2 ) 14 ) 3 P) ( cis -6c, 85%) but subsequent reaction with HCl affords trans -Pt(Cl)(Et)(P((CH 2 ) 14 ) 3 P) ( trans -7c, 45%) directly. When previously reported cis -Pt(Ph) 2 (P((CH 2 ) 14 ) 3 P) is treated with HCl (1 equiv.), cis - and trans -Pt(Cl)(Ph)(P((CH 2 ) 14 ) 3 P) are isolated (44%, 29%), with the former converting to the latter at 100 °C. Reactions of trans -5c and LiBr or NaI afford the halide complexes trans -Pt(X)(Me)(P((CH 2 ) 14 ) 3 P) ( trans -9c, 88%; trans -10c, 87%). Thermolyses and DFT calculations that include acyclic model compounds establish trans > cis stabilities for all except the dialkyl complexes, for which energies can be closely spaced. The σ donor strengths of the non-phosphine ligands are assigned key roles in the trends. The crystal structures of cis -4c, trans -5c, trans -7c, and trans -10c are determined and analyzed together with the computed structures. 

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3. Formation of Cyclopropanes via Activation of (γ-Methoxy)alkyl Gold(I) Complexes with Lewis Acids

   https://doi.org/10.1021/acs.organomet.0c00324  

   Kim, Nana ; Widenhoefer, Ross A. ( September 2020 , Organometallics)
4. Synthesis and Reactivity of Palladium(II) Alkyl Complexes that Contain Phosphine-cyclopentanesulfonate Ligands

   https://doi.org/10.1021/acs.organomet.7b00572  

   Black, Rebecca E. ; Jordan, Richard F. ( August 2017 , Organometallics)
5. Ring-Opening Polymerization of ε-Caprolactone Utilizing Aluminum Alkyl Complexes Bearing Dianionic Scorpionate Ligands

   https://doi.org/10.1021/acs.organomet.1c00400  

   Cooper, Elizabeth N. ; Averkiev, Boris ; Day, Victor W. ; Sues, Peter E. ( September 2021 , Organometallics)