X-ray crystallographic and variable-temperature high-field carbon-13 NMR studies of R-CCo3(CO)9 and R-CCo3 (CO)6 (tripod) clusters [R = Ch3, (4-CH3OC6H4)2CH, (2-CIC6H4) (4-CIC6H4)CH; tripod = 1,1,1-tris(diphenylphosphino)methane]enantiomerization of a chiral cluster via the inversion of a molecular propeller

1991 ◽  
Vol 10 (5) ◽  
pp. 1383-1390 ◽  
Author(s):  
Michael F. D'Agostino ◽  
Christopher S. Frampton ◽  
Michael J. McGlinchey
Keyword(s):  
High Field ◽  
Variable Temperature ◽  
Nmr Studies ◽  
X Ray

Article

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1057-1065
Author(s):  
John T Edward ◽  
Francis L Chubb ◽  
Denis FR Gilson ◽  
Rosemary C Hynes ◽  
Françoise Sauriol ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Acidic Solution ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Cage Compounds ◽  
Amine Nitrogen ◽  
X Ray ◽  
Bridgehead Nitrogen ◽  
C Nmr

Three new cage peroxides, 1,6-diaza-3,4,8,9-tetraoxabicyclo[4.4.2]dodecane (3a),1,6-diaza-3,4,8,9-tetraoxa-11-methylbicyclo[4.4.2]dodecane (3b), and 1,6-diaza-3,4,8,9-tetraoxatricyclo[4.4.2.411,12]hexadecane (4), have been prepared by reaction of 1,2-diaminoethane, 1,2-diaminopropane, and trans-1,2-diaminocyclohexane, respectively, with formaldehyde and hydrogen peroxide in aqueous acidic solution. Their structures have been established by X-ray diffraction, and show the bridgehead nitrogen atoms to be predominantly sp2 hybridized. The structures accord with 1H and 13C NMR spectra. Variable temperature NMR studies show that the diperoxide 3a begins to undergo rapid inversion (on the NMR time scale) at about 303 K; up to 370 K the diperoxides 3b and 4 show no conformational change.Key words: cage compounds, formaldehyde, peroxides, amine nitrogen, hybridization.

Exploring anagostic interactions in 5,15-porphodimethene metal complexes

2014 ◽  
Vol 43 (21) ◽  
pp. 7699-7703 ◽  
Author(s):  
M. G. Derry Holaday ◽  
Gourav Tarafdar ◽  
Arun Kumar ◽  
M. L. P. Reddy ◽  
A. Srinivasan
Keyword(s):  
Metal Complexes ◽  
Single Crystal ◽  
Variable Temperature ◽  
Nmr Studies ◽  
X Ray

By using 5,15-porphodimethene metal complexes, the weak noncovalent anagostic interaction is explored using variable temperature NMR studies and is further confirmed by single crystal X-ray analysis.

Iridium(I) complexes containing bidentate pyrazolylgallate ligands. X-ray crystal structures of [Me2Gapz2]Ir(COD), [Ir(μ-pz)(CO)2]2, and [Ir(μ-3,5-Me2pz)(CO)2]2

1985 ◽  
Vol 63 (3) ◽  
pp. 692-702 ◽  
Author(s):  
Sophia Nussbaum ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Crystal Structures ◽  
Variable Temperature ◽  
Hydrogenation Reaction ◽  
Synthesis And Characterization ◽  
Nmr Studies ◽  
X Ray ◽  
H Nmr ◽  
Measurable Activity

The synthesis and characterization of a number of Ir(I) complexes incorporating bidentate, chelating, pyrazolylgallate ligands are described. Non-rigidity for some of the complexes in solution has been demonstrated by variable temperature 1H nmr studies. Crystal structures of three complexes, [Me2Gapz2]Ir(COD), [Ir(μ-pz)(CO)2]2, and [Ir(μ-3,5-Me2pz)(CO)2]2 are reported and confirm the expected boat conformations for the six-membered M—(N—N)2—Ir rings (where M = Ir or Ga) in the compounds. One of the complexes studied has exhibited measurable activity as a catalyst in the hydrogenation reaction of cyclohexene.

The crystal structure of cis-chlorobis(triethylphosphine)-1,8-naphthyridineplatinum(II) tetrafluoroborate, [PtCl(PEt3)2(naph)]BF4, a complex containing a monodentate 1,8-naphthyridine ligand

1978 ◽  
Vol 56 (4) ◽  
pp. 450-455 ◽  
Author(s):  
Gordon W. Bushnell ◽  
Keith R. Dixon ◽  
Masood A. Khan
Keyword(s):  
Crystal Structure ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Interatomic Distances ◽  
X Ray ◽  
Heterocyclic Ligand ◽  
Square Planar ◽  
Cell Dimensions ◽  
R Value

The crystal structure of cis-chlorobis(triethylphosphine)-1,8-naphthyridineplatinum(II) tetrafluoroborate has been determined by single crystal X-ray diffraction and refined to an R-value of 0.063. The cell dimensions are a = 1.4246, b = 1.2676, c = 1.6530 nm, β = 115.66°. The space group is P21/c with 4 molecules per unit cell, and the measured density is 1.665 g cm−3. The structure is essentially a 4-coordinate square planar platinum(II) complex containing monodentate 1,8-naphthyridine. Interatomic distances to platinum are: Pt—Cl, 236.6(4); Pt—P(1), 225.4(4); Pt—P(2), 225.2(4); Pt—N(1), 208.3(11); and Pt—N(2), 304.5(14) pm. The structure is discussed in relation to variable temperature nmr studies of solutions, which indicate fluxional behaviour of the heterocyclic ligand.

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