Figure 2.10 Correlation between levels under Russell-Saunders coupling (left) and yy coupling (right). |

Finally, we show that the second-order coupling between direct tunneling transitions is subdominant to the already computed quantities. Consider an interaction of the form yy l,-2 )(2,l + H.C. If one repeats simple-mindedly the steps leading to Eq. (75), one obtains the following simple expression for the free energy correction due to interaction between the underlying structural transitions ... [Pg.188]

In Section V.B, we discussed to some extent the 3 x 3 adiabatic-to-diabatic transformation matrix A(= A(31) for a tri-state system. This matrix was expressed in terms of three (Euler-type) angles yy,i = 1,2,3 [see Eq. (81)], which fulfill a set of three coupled, first-order, differential equations [see Eq. (82)]. [Pg.860]

In addition to /3-H elimination, olefin insertion, and protonolysis, the cr-metal intermediate has also proved to be capable of undergoing a reductive elimination to bring about an alkylative alkoxylation. Under Pd catalysis, the reaction of 4-alkenols with aryl halides affords aryl-substituted THF rings instead of the aryl ethers that would be produced by a simple cross-coupling mechanism (Equation (126)).452 It has been suggested that G-O bond formation occurs in this case by yy/z-insertion of a coordinated alcohol rather than anti-attack onto a 7r-alkene complex.453... [Pg.684]

The components Xx, Yy, Zz are perpendicular to the faces of the cube, and are either compressive or tensile stresses depending on the sign. The residual six components are tangential stresses because they run parallel to the cube faces. They comprise couples, whose moments in a state of equilibrium are equal... [Pg.11]

HMQC and HSQC are about equally sensitive, the sensitivity being proportional to (Yx)5 2, but as the HSQC pulse sequence uses more than twice as many pulses as HMQC, the latter is preferred (especially on older spectrometers). Both use two polarization transfer steps while HETCOR uses only one transfer. If the coupling constants vary within the sample, HETCOR might be a better choice for lower losses in polarization transfers. Since the sensitivity of HETCOR is proportional to (yx)3 2(YY), the choice of nucleus for detection is not trivial. [Pg.299]

Potential difference in reactivity between two G-B bonds allowed the transformation of l,2-bis(boryl)-l-alkenes to 1-alkenylboranes via a cross-coupling with the aryl, 1-alkenyl, benzyl, and cinnamyl halides (Equation (23)).211-213 This tandem procedure synthetically equivalent to a yy/z-carboboration of alkynes was used for synthesizing Tamoxifen derivatives via stepwise double coupling with two of the G-B bonds.212,213 Hydrogenation of the resulting bisborylalk-enes with a chiral rhodium catalyst is synthetically equivalent to an asymmetric diboration of alkenes (Equation (24)).214... [Pg.160]

Radical coupling of organic halides with alkenes or alkynes takes place intermolecularly (Equation (12)).54 Tin hydride-mediated radical additions to a series of a-methyleneglutarates furnish 2,4-dialkyl-substituted glutarates.55 Using MgBr2-OEt2 as an additive, exclusive yy/t-selectivities are achieved upon tert-butyl radical addition at —78 °C. [Pg.344]

Anomalous yy/z-diastereoselectivity of indium-mediated coupling of aldehydes with bromides (Z)- and (E)A2 has been reported (Scheme 45). The reaction affords high syn-selectivity (43/44) regardless of the allylic bromide geometry. Preliminary studies on the enantioselective indium-mediated allylation have been attempted and it has been found that the desired products can be obtained in moderate yield with high. //-selectivity and enantioselectivity (Equation (23)).99... [Pg.673]

Neuropeptide Y (NPY) receptors are a class of G-protein-coupled receptors that are activated by the closely related peptide hormones NPY, peptide YY and pancreatic polypeptide. These receptors are involved in control of a diverse set of behavioural processes, including appetite, circadian rhythm and anxiety. AgRP is a receptor antagonist of CNS melanocortin receptors and appears to have an important role in the control of food intake. Hypothalamic POMC neurons are important mediators in the regulation of feeding behaviour, insulin levels and ultimately body weight. [Pg.44]

The power-law exponent /x is around 4.0-5.0. A similar result is obtained for the yield stress in shear cr, except the exponent is smaller,

physiological relevance in murine cardiac myocytes. Circ Res 1999 84 43-52. [Pg.103]

AJ — Jz z l/ ( fx A/ "b yy and Jx x " yy were compared with the experimentally determined values. Here, the z axis is parallel with the molecular symmetry axis. A very good agreement was obtained between the calculated and experimental isotropic couplings, and a reasonable agreement was found for the anisotropic values. For example, in the case of CHF3, the calculated and experimental values for A /(F, F) are —232 Hz and —200 Hz, respectively. [Pg.136]

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