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1. Crystal structures of [Cu(phen)(H 2 O) 3 ( M F 6 )]·H 2 O ( M = Ti, Zr, Hf) and [Cu(phen)(H 2 O) 2 F] 2 [HfF 6 ]·H 2 O

   https://doi.org/10.1107/S2056989021000645  

   Nisbet, Matthew L. ; Poeppelmeier, Kenneth R. ( February 2021 , Acta Crystallographica Section E Crystallographic Communications)

   null (Ed.)

   The crystal structures of three bridged bimetallic molecular compounds, namely, triaqua-2κ 3 O -μ-fluorido-pentafluorido-1κ 5 F -(1,10-phenanthroline-2κ 2 N , N ′)copper(II)titanium(IV) monohydrate, [Cu(TiF 6 )(phen)(H 2 O) 3 ]·H 2 O (phen is 1,10-phenanthroline, C 12 H 8 N 2 ), (I), triaqua-2κ 3 O -μ-fluorido-pentafluorido-1κ 5 F -(1,10-phenanthroline-2κ 2 N , N ′)copper(II)zirconium(IV) monohydrate, [Cu(ZrF 6 )(phen)(H 2 O) 3 ]·H 2 O, (II), and triaqua-2κ 3 O -μ-fluorido-pentafluorido-1κ 5 F -(1,10-phenanthroline-2κ 2 N , N ′)copper(II)hafnium(IV) monohydrate, [Cu(HfF 6 )(phen)(H 2 O) 3 ]·H 2 O, (III), and one molecular salt, bis[diaquafluorido(1,10-phenanthroline-κ 2 N , N ′)copper(II)] hexafluoridohafnate(IV) dihydrate, [CuF(phen)(H 2 O) 2 ] 2 [HfF 6 ]·2H 2 O, (IV), are reported. The bridged bimetallic compounds adopt Λ-shaped configurations, with the octahedrally coordinated copper(II) center linked to the fluorinated early transition metal via a fluoride linkage. The extended structures of these Λ-shaped compounds are organized through both intra- and intermolecular hydrogen bonds and intermolecular π–π stacking. The salt compound [Cu(phen)(H 2 O) 2 F] 2 [HfF 6 ]·H 2 O displays an isolated square-pyramidal Cu(phen)(H 2 O) 2 F + complex linked to other cationic complexes and isolated HfF 6 2− anions through intermolecular hydrogen-bonding interactions. 

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2. Dispersion‐Force‐Assisted Disproportionation: A Stable Two‐Coordinate Copper(II) Complex

   https://doi.org/10.1002/ange.201605061  

   Wagner, Clifton L. ; Tao, Lizhi ; Thompson, Emily J. ; Stich, Troy A. ; Guo, Jingdong ; Fettinger, James C. ; Berben, Louise A. ; Britt, R. David ; Nagase, Shigeru ; Power, Philip P. ( July 2016 , Angewandte Chemie)

   The synthesis of the first linear coordinated Cu^IIcomplex Cu{N(SiMe₃)Dipp}₂(1Dipp=C₆H₅‐2,6Prⁱ₂) and its Cu^Icounterpart [Cu{N(SiMe₃)Dipp}₂]⁻(2) is described. The formation of1proceeds through a dispersion force‐driven disproportionation, and is the reaction product of a Cu^Ihalide and LiN(SiMe₃)Dipp in a non‐donor solvent. The synthesis of2is accomplished by preventing the disproportionation into1by using the complexing agent 15‐crown‐5. EPR spectroscopy of1provides the first detailed study of a two‐coordinate transition‐metal complex indicating strong covalency in the Cu−N bonds.

    

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3. Copper‐Catalyzed C(sp 3 )−H Amidation: Sterically Driven Primary and Secondary C−H Site‐Selectivity

   https://doi.org/10.1002/anie.201810556  

   Bakhoda, Abolghasem ; Jiang, Quan ; Badiei, Yosra M. ; Bertke, Jeffery A. ; Cundari, Thomas R. ; Warren, Timothy H. ( February 2019 , Angewandte Chemie International Edition)

   Undirected C(sp³)−H functionalization reactions often follow site‐selectivity patterns that mirror the corresponding C−H bond dissociation energies (BDEs). This often results in the functionalization of weaker tertiary C−H bonds in the presence of stronger secondary and primary bonds. An important, contemporary challenge is the development of catalyst systems capable of selectively functionalizing stronger primary and secondary C−H bonds over tertiary and benzylic C−H sites. Herein, we report a Cu catalyst that exhibits a high degree of primary and secondary over tertiary C−H bond selectivity in the amidation of linear and cyclic hydrocarbons with aroyl azides ArC(O)N₃. Mechanistic and DFT studies indicate that C−H amidation involves H‐atom abstraction from R‐H substrates by nitrene intermediates [Cu](κ²‐N,O‐NC(O)Ar) to provide carbon‐based radicals R^.and copper(II)amide intermediates [Cu^II]‐NHC(O)Ar that subsequently capture radicals R^.to form products R‐NHC(O)Ar. These studies reveal important catalyst features required to achieve primary and secondary C−H amidation selectivity in the absence of directing groups.

    

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4. Copper‐Catalyzed C(sp 3 )−H Amidation: Sterically Driven Primary and Secondary C−H Site‐Selectivity

   https://doi.org/10.1002/ange.201810556  

   Bakhoda, Abolghasem ; Jiang, Quan ; Badiei, Yosra M. ; Bertke, Jeffery A. ; Cundari, Thomas R. ; Warren, Timothy H. ( February 2019 , Angewandte Chemie)

   Undirected C(sp³)−H functionalization reactions often follow site‐selectivity patterns that mirror the corresponding C−H bond dissociation energies (BDEs). This often results in the functionalization of weaker tertiary C−H bonds in the presence of stronger secondary and primary bonds. An important, contemporary challenge is the development of catalyst systems capable of selectively functionalizing stronger primary and secondary C−H bonds over tertiary and benzylic C−H sites. Herein, we report a Cu catalyst that exhibits a high degree of primary and secondary over tertiary C−H bond selectivity in the amidation of linear and cyclic hydrocarbons with aroyl azides ArC(O)N₃. Mechanistic and DFT studies indicate that C−H amidation involves H‐atom abstraction from R‐H substrates by nitrene intermediates [Cu](κ²‐N,O‐NC(O)Ar) to provide carbon‐based radicals R^.and copper(II)amide intermediates [Cu^II]‐NHC(O)Ar that subsequently capture radicals R^.to form products R‐NHC(O)Ar. These studies reveal important catalyst features required to achieve primary and secondary C−H amidation selectivity in the absence of directing groups.

    

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5. Calcium‐Ion Binding Mediates the Reversible Interconversion of Cis and Trans Peroxido Dicopper Cores

   https://doi.org/10.1002/ange.202105421  

   Vargo, Natasha P. ; Harland, Jill B. ; Musselman, Bradley W. ; Lehnert, Nicolai ; Ertem, Mehmed Z. ; Robinson, Jerome R. ( July 2021 , Angewandte Chemie)

   Coupled dinuclear copper oxygen cores (Cu₂O₂) featured in type III copper proteins (hemocyanin, tyrosinase, catechol oxidase) are vital for O₂transport and substrate oxidation in many organisms.μ‐1,2‐cisperoxido dicopper cores (^CP) have been proposed as key structures in the early stages of O₂binding in these proteins; their reversible isomerization to other Cu₂O₂cores are directly relevant to enzyme function. Despite the relevance of such species to type III copper proteins and the broader interest in the properties and reactivity of bimetallic^CPcores in biological and synthetic systems, the properties and reactivity of^CPCu₂O₂species remain largely unexplored. Herein, we report the reversible interconversion ofμ‐1,2‐transperoxido (^TP) and^CPdicopper cores. Ca^IImediates this process by reversible binding at the Cu₂O₂core, highlighting the unique capability for metal‐ion binding events to stabilize novel reactive fragments and control O₂activation in biomimetic systems.

    

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