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1. Crystal structures of phosphine-supported (η 5 -cyclopentadienyl)molybdenum(II) propionyl complexes

   https://doi.org/10.1107/S2056989021008008  

   Whited, Matthew T. ; Ball, Margaret A. ; Block, Alison ; Brewster, Benjamin A. ; Ferrer, LouLou ; Jin-Lee, Helen J. ; King, Colby J. ; North, Jamie D. ; Shelton, Inger L. ; Wilson, David G. ( September 2021 , Acta Crystallographica Section E Crystallographic Communications)

   Three cyclopentadienylmolybdenum(II) propionyl complexes featuring triarylphosphine ligands with different para substituents, namely, dicarbonyl(η 5 -cyclopentadienyl)propionyl(triphenylphosphane-κ P )molybdenum(II), [Mo(C 5 H 5 )(C 3 H 5 O)(C 18 H 15 P)(CO) 2 ], ( 1 ), dicarbonyl(η 5 -cyclopentadienyl)propionyl[tris(4-fluorophenyl)phosphane-κ P ]molybdenum(II), [Mo(C 5 H 5 )(C 3 H 5 O)(C 18 H 12 F 3 P)(CO) 2 ], ( 2 ), and dicarbonyl(η 5 -cyclopentadienyl)propionyl[tris(4-methoxyphenyl)phosphane-κ P ]molybdenum(II) dichloromethane solvate, [Mo(C 5 H 5 )(C 3 H 5 O)(C 21 H 21 O 3 P)(CO) 2 ]·CH 2 Cl 2 , ( 3 ), have been prepared from the corresponding ethyl complexes via phosphine-induced migratory insertion. These complexes exhibit four-legged piano-stool geometries with molecular structures quite similar to each other and to related acetyl complexes. The extended structures of the three complexes differ somewhat, with the para substituent of the triarylphosphine of ( 2 ) (fluoro) or ( 3 ) (methoxy) engaging in non-classical C—H...F or C—H...O hydrogen-bonding interactions. The structure of ( 3 ) exhibits modest disorder in the position of one Cl atom of the dichloromethane solvent, which was modeled with two sites showing approximately equivalent occupancies [0.532 (15) and 0.478 (15)]. 

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2. Crystal structures of trans -acetyldicarbonyl(η 5 -cyclopentadienyl)(1,3,5-triaza-7-phosphaadamantane)molybdenum(II) and trans -acetyldicarbonyl(η 5 -cyclopentadienyl)(3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane)molybdenum(II)

   https://doi.org/10.1107/S2056989020003679  

   Anstey, Mitchell R. ; Bost, John L. ; Grumman, Anna S. ; Kennedy, Nicholas D. ; Whited, Matthew T. ( April 2020 , Acta Crystallographica Section E Crystallographic Communications)

   null (Ed.)

   The title compounds, [Mo(C 5 H 5 )(COCH 3 )(C 6 H 12 N 3 P)(CO) 2 ], (1), and [Mo(C 5 H 5 )(COCH 3 )(C 9 H 16 N 3 O 2 P)(C 6 H 5 ) 2 ))(CO) 2 ], (2), have been prepared by phosphine-induced migratory insertion from [Mo(C 5 H 5 )(CO) 3 (CH 3 )]. The molecular structures of these complexes are quite similar, exhibiting a four-legged piano-stool geometry with trans -disposed carbonyl ligands. The extended structures of complexes (1) and (2) differ substantially. For complex (1), the molybdenum acetyl unit plays a dominant role in the organization of the extended structure, joining the molecules into centrosymmetrical dimers through C—H...O interactions with a cyclopentadienyl ligand of a neighboring molecule, and these dimers are linked into layers parallel to (100) by C—H...O interactions between the molybdenum acetyl and the cyclopentadienyl ligand of another neighbor. The extended structure of (2) is dominated by C—H...O interactions involving the carbonyl groups of the acetamide groups of the DAPTA ligand, which join the molecules into centrosymmetrical dimers and link them into chains along [010]. Additional C—H...O interactions between the molybdenum acetyl oxygen atom and an acetamide methyl group join the chains into layers parallel to (101). 

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3. Crystal structure of bromidopentakis(tetrahydrofuran-κ O )magnesium bis[1,2-bis(diphenylphosphanyl)benzene-κ 2 P , P ′]cobaltate(−1) tetrahydrofuran disolvate

   https://doi.org/10.1107/S2056989019001671  

   Girigiri, Patience B. ; Carpenter, Stephanie H. ; Brennessel, William W. ; Neidig, Michael L. ( February 2019 , Acta Crystallographica Section E Crystallographic Communications)

   Structural characterization of the ionic title complex, [MgBr(THF) 5 ][Co(dpbz) 2 ]·2THF [THF is tetrahydrofuran, C 4 H 8 O; dpbz is 1,2-bis(diphenylphosphanyl)benzene, C 30 H 24 P 2 ], revealed a well-separated cation and anion co-crystallized with two THF solvent molecules that interact with the cation via weak C—H...O contacts. The geometry about the cobalt center is pseudotetrahedral, as is expected for a d 10 metal center, only deviating from an ideal tetrahedral geometry because of the restrictive bite angles of the bidentate phosphane ligands. Three THF ligands of the cation and one co-crystallized THF solvent molecule are each disordered over two orientations. In the extended structure, the cations and THF solvent molecules are arranged in (100) sheets that alternate with layers of anions, the latter of which show various π-interactions, which may explain the particular packing arrangement. 

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4. Temperature dependence of collisional broadening and shift for the Kr 4 p 6 S 01→5 p [3/2] 2 electronic transition

   https://doi.org/10.1364/AO.380102  

   Sahoo, Abinash ; Zelenak, Dominic ; Narayanaswamy, Venkateswaran ( February 2020 , Applied Optics)

   Temperature scaling of collisional broadening parameters for krypton (absorber)$4p^6{S}_0^1\to <\#comment/>5p[3/2{]}_2$electronic transition centered at 107.3 nm in the presence of major combustion species (perturber) is investigated. The absorption spectrum in the vicinity of the transition is obtained from the fluorescence due to the two-photon excitation scan of krypton. Krypton was added in small amounts to major combustion species such as${\mathrm{C}\mathrm{H}}_4$,${\mathrm{C}\mathrm{O}}_2$,${\mathrm{N}}_2$, and air, which then heated to elevated temperatures when flowed through a set of heated coils. In a separate experimental campaign, laminar premixed flat flame product mixtures of methane combustion were employed to extend the investigations to higher temperature ranges relevant to combustion. Collisional full width half maximum (FWHM) ($w_C$) and shift (${\mathrm{\delta <\#comment/>}}_C$) were computed from the absorption spectrum by synthetically fitting Voigt profiles to the excitation scans, and their corresponding temperature scaling was determined by fitting power-law temperature dependencies to the$w_C$and${\mathrm{\delta <\#comment/>}}_C$data for each perturber species. The temperature exponents of$w_C$and${\mathrm{\delta <\#comment/>}}_C$for all considered combustion species (perturbers) were$-<\#comment/>0.73$and$-<\#comment/>0.6$, respectively. Whereas the temperature exponents of$w_C$are closer to the value ($-<\#comment/>0.7$) predicted by the dispersive interaction collision theory, the corresponding exponents of${\mathrm{\delta <\#comment/>}}_C$are in between the dispersive interaction theory and the kinetic theory of hard-sphere collisions. Comparison with existing literature on broadening parameters of NO, OH, and CO laser-induced fluorescence spectra reveal interesting contributions from non-dispersive interactions on the temperature exponent.

    

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5. Crystal structure of bromido­penta­kis­(tetra­hydro­furan-κO)magnesium bis­[1,2-bis­(di­phenyl­phosphan­yl)benzene-κ2P,P′]cobaltate(−1) tetra­hydro­furan disolvate

   https://doi.org/S2056989019001671  

   Girigiri, P. B. ( January 2019 , Acta crystallographica)

   Structural characterization of the ionic title complex, [MgBr(THF)5][Co(dpbz)2]·2THF [THF is tetra­hydro­furan, C4H8O; dpbz is 1,2-bis­(di­phenyl­phosphan­yl)benzene, C30H24P2], revealed a well-separated cation and anion co-crystallized with two THF solvent mol­ecules that inter­act with the cation via weak C—H...O contacts. The geometry about the cobalt center is pseudo­tetra­hedral, as is expected for a d10 metal center, only deviating from an ideal tetra­hedral geometry because of the restrictive bite angles of the bidentate phosphane ligands. Three THF ligands of the cation and one co-crystallized THF solvent mol­ecule are each disordered over two orientations. In the extended structure, the cations and THF solvent mol­ecules are arranged in (100) sheets that alternate with layers of anions, the latter of which show various π-inter­actions, which may explain the particular packing arrangement. 

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