Reversible Heterolytic Si–H Bond Activation by an Intramolecular Frustrated Lewis Pair

2012 ◽  
Vol 67 (10) ◽  
pp. 987-994 ◽  
Author(s):  
Wanli Nie ◽  
Hendrik F. T. Klare ◽  
Martin Oestreich ◽  
Roland Fröhlich ◽  
Gerald Kehr ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Ambient Temperature ◽  
Bond Activation ◽  
Variable Temperature ◽  
Crystal Structure Analysis ◽  
Nmr Studies ◽  
X Ray ◽  
Predominant Species ◽  
Frustrated Lewis Pair

The intramolecular frustrated P/B Lewis pair Mes2PCH2CH2B(C6F5)2 (7) reacts readily with phenylsilane by heterolytic cleavage of the Si-H bond to give the zwitterion [Mes2(PhH2Si)P+CH2CH2B-H(C6F5)2] (8a), which has been fully characterized and its structure confirmed by X-ray crystal structure analysis. Variable-temperature NMR studies revealed that the reaction is reversible. Adduct 8a is the predominant species (ca. 98%) in CD2Cl2 solution at low temperature (193 K), whereas at ambient temperature (299 K) it exists in a ca. 7 : 3 equilibrium with unreacted 7 and PhSiH3. Diphenylsilane reacted similarly with the frustrated Lewis pair 7, however, the equilibrium was found to favor the starting materials in the investigated temperature range.

Ferrocenyl-penta-(β-naphthyl)benzene — Synthesis, structure, and dynamic behaviour

2003 ◽  
Vol 81 (11) ◽  
pp. 1180-1186 ◽  
Author(s):  
Laura E Harrington ◽  
James F Britten ◽  
Michael J McGlinchey
Keyword(s):  
Crystal Structure ◽  
Carbon Monoxide ◽  
Low Temperature ◽  
Dynamic Behaviour ◽  
Variable Temperature ◽  
Alder Reaction ◽  
Diels Alder ◽  
Nmr Studies ◽  
X Ray ◽  
Diels Alder Reaction

3-Ferrocenyl-2,4,5-tri-(β-naphthyl)cyclopentadienone undergoes a Diels–Alder reaction with di-(β-naphthyl) acetylene to yield, after elimination of carbon monoxide, ferrocenyl-penta-(β-naphthyl)benzene (4). 1H and 13C variable-temperature NMR studies on 4 reveal the existence of multiple diastereoisomers at low temperature. These data are interpreted in terms of slowed rotation of the naphthyl groups, and are supported by the X-ray crystal structure of 4, which exhibits disorder at three of the naphthyl sites.Key words: sterically crowded molecules, hindered rotations, crystallography, NMR.

ChemInform Abstract: Synthesis of the First Decametal Nitrido Cluster; X-Ray Crystal Structure Analysis and 14N NMR Studies of ((Ph3P)2N)(Ru10N(CO)24)

ChemInform ◽  
2010 ◽  
Vol 23 (10) ◽  
pp. no-no
Author(s):  
P. J. BAILEY ◽  
G. C. CONOLE ◽  
B. F. G. JOHNSON ◽  
J. LEWIS ◽  
M. MCPARTLIN ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
Nmr Studies ◽  
X Ray ◽  
14N Nmr

X-ray and neutron diffraction investigation at 298 K of NH4I · NH3 and ND4I · ND3 containing the cation H3N – H … NH3+ and D3N – D … ND3+

1992 ◽  
Vol 200 (3-4) ◽  
Author(s):  
H. J. Berthold ◽  
E. Vonholdt ◽  
R. Wartchow ◽  
T. Vogt
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Neutron Diffraction ◽  
Single Crystal ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
Single Crystal Structure ◽  
X Ray ◽  
Single Crystal Structure Analysis

AbstractNHA single crystal structure analysis of NThe deuterated compound NThe structures of the ordered low temperature phases will be reported separately.

scholarly journals Synthesis of a Chiral Meso-Like Ansa-Zirconocene Complex and its Use for the Catalytic Formation of Low Molecular Weight Polypropylene

1995 ◽  
Vol 50 (6) ◽  
pp. 982-989 ◽  
Author(s):  
Sven Thiele ◽  
Gerhard Erker ◽  
Cornelia Fritze ◽  
Christian Psiorz ◽  
Roland Fröhlich
Keyword(s):  
Crystal Structure ◽  
Molecular Weight ◽  
Double Bond ◽  
Ambient Temperature ◽  
Organic Synthesis ◽  
Crystal Structure Analysis ◽  
Low Molecular Weight ◽  
X Ray ◽  
Catalyst Systems ◽  
Double Bond Shift

Reaction of lithium(neomenthylcyclopentadienid) 3 with dimethyldichlorosilane gives dimethylbis[3-(neomenthyl)cyclopentadienyl]silane 4 regioselectively as a mixture of double bond shift isomers (57% isolated). Deprotonation with 2 equiv. of butyllithium followed by treatment with zirconiumtetrachloride furnished a mixture of the three {dimethylsilylenbis[η5-3-(neomenthyl)cyclopentadienyl][zirconium dichloride diastereomers from which the pure meso-like isomer 6e [p -R (1′S ,3 ′R ,4 ′R),p -S (1′S ,3 ′R ,4 ′R)] was isolated by fractional crystallization. Complex 6 c was characterized by an X-ray crystal structure analysis. Its D 1 - Zr - D 2 angle of 126.8° is very similar as observed in bis(η-cyclopentadienyl) zirconium dichloride (D 1 and D 2 denote the centroids of the cyclopentadienyl rings). The homogeneous 6c/methylalumoxane Ziegler-type catalyst produces polypropylene of low molecular weight (Mη ≈ 670 at ambient temperature). Related catalyst systems may find interesting applications in organic synthesis.

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.

scholarly journals Raise the anchor! Synthesis, X-ray and NMR characterization of 1,3,5-triazinanes with an axial tert-butyl group

2020 ◽  
Vol 18 (41) ◽  
pp. 8386-8394 ◽  
Author(s):  
Alexey V. Kletskov ◽  
Anastasya D. Zatykina ◽  
Mariya V. Grudova ◽  
Anna A. Sinelshchikova ◽  
Mikhail S. Grigoriev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Single Crystal ◽  
Crystal Structure Analysis ◽  
X Ray ◽  
Butyl Group ◽  
Tert Butyl Group ◽  
Nmr Characterization ◽  
Single Crystal Structure Analysis

N-t-Bu-N′,N′′-Disulfonamide-1,3,5-triazinanes were synthesized and studied by X-ray single crystal structure analysis and dynamic low-temperature NMR.

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