نتایج جستجو برای: nitrogen inversion barrier

تعداد نتایج: 251299  

2015
William H Hersh

The reaction of the diamidite, (iPr2N)2PH, with acyl chlorides proceeds with the loss of HCl to give the corresponding acyl diamidites, RC(O)P(N(iPr)2)2 (R = Me (7), Ph (9)), without the intervention of sodium to give a phosphorus anion. The structure of 9 was confirmed by single-crystal X-ray diffraction. The coupling of the diamidites 7 and 9 with 5'-O-DMTr-thymidine was carried out with N-me...

Azadi, Baloo, Farrahi, Mirsalim,

In the present paper, a complete literatures review of thermal barrier coating applications in diesel engines is performed to select a proper type and to find coating effects. The coating system has effects on the fuel consumption, the power and the combustion efficiency, pollution contents and the fatigue lifetime of engine components. Usually there are several beneficial influences by appl...

2015
Angelika Alonso Philipp Eisele Anne D. Ebert Martin Griebe Britta Engelhardt Kristina Szabo Michael G. Hennerici Achim Gass

OBJECTIVE To investigate the blood-CSF barrier (BCSFB) dysfunction in aseptic meningitis. METHODS In our case series of 14 patients with acute aseptic meningitis, we compared MRI characteristics with CSF findings. RESULTS Contrast enhancement in the sulcal space in a leptomeningeal pattern was visualized in 7 patients with BCSFB dysfunction categorized as moderate to severe as evidenced by ...

Journal: :Chemical communications 2013
Alexander J Hough Ivan Prokes James H R Tucker Michael Shipman Tiffany R Walsh

Rates of pyramidal motion in an aziridine are controlled by reversible trans to cis photoisomerisation of an azobenzene unit attached to the ring nitrogen atom. The dynamics of the inversion process and activation parameters are derived by variable temperature NMR, and are supported by ab initio calculations.

2013
Steven S Y Wong Michael G Brant Christopher Barr Allen G Oliver Jeremy E Wulff

Dipolar addition of cyclic azomethine imines with cyclic vinyl sulfones gave rise to functionalized tricycles that exhibited fluxional behavior in solution at room temperature. The scope of the synthetic methodology was explored, and the origin of the fluxional behavior was probed by NMR methods together with DFT calculations. This behavior was ultimately attributed to stereochemical inversion ...

Journal: :IEEJ Transactions on Fundamentals and Materials 1998

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