Gauche molecular modelling

Construct a molecular model corresponding to the Fischer projection of rneso 2 3 dibro mobutane Convert this molecular model to a staggered conformation in which the bromines are anti to one another Are the methyl groups anti or gauche to one another in this staggered con formation" ... 

Construct molecular models of the gauche and anti conformations of 1 2 ethanediol and explore the possibility of intramolecular hydrogen bond formation in each one... 

Find the molecular model of 18 crown 6 (see Figure 16 2) on Learning By Modeling and examine its electrostatic potential map View the map in vanous modes (dots contours and as a transparent surface) Does 18 crown 6 have a dipole moment Are vicinal oxygens anti or gauche to one another"d... 

A comparison of the data for compounds 61 and 62 showed that the double bond could be located by examining the chemical shift of C-7. From molecular models it was found that when the double bond was between C-8 and C-9 a y gauche interaction existed between the axial proton on C-l 1 and the a proton on C-7. This interaction was used to explain the higher field shift of C-7 in compounds with the 8,9-double bond such as 61. When the double bond was between C-l 1 and C-l2 these interactions were no longer present and C-7 appeared at lower field in 62. The chemical shift at C-7 was... 

Fig. 2. Projections along a PN bond for anti (a) and gauche (b) molecular models of Me2NPCl2...

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