Molecular model, construction

He, F.-C., Liu, L.-B., and Li, X.-V. (1990). Molecular models constructed in an easy way. Part 1. Models of tetrahedron, trigonal bipyramid, octahedron, pentagonal bipyramid and capped octahedron, y. Chem. Educ. 67,556—558. 

A half-chair conformation of a crystalline monosaccharide has not been observed. A half-chair conformation for the fourth 2-acetamido-2-deoxy-/3-D-glucopyranosyl residue (residue D) in the lysozyme substrate has not been detected, although, on the basis of model fitting, its presence has been suggested (see p. 96). 2-Acetamido-2-deoxy-/3-D-glucosyl groups were added to a molecular model constructed by use of data obtained from the nature of the enzyme-trisaccharide complex it was implicit that the lifetime of the half-chair conformation would be quite short. 

Explain the qualities of the negative space in the molecular models constructed (in terms of size, shape, and relationship to positive space) and arrange the models as a microsculpture, making good use of the negative space. 

Fig. 4. Photograph of a molecular model, constructed from CPK correctly-proportioned spacefilling atomic models, depicting phenylalanine/phenylalanine group adherence from which it can be appreciated that this allows a restricted circular movement of the attached chains along the contract area, thereby inhibiting indiscriminate random movement of the deconformed segments.

Let us consider a system of N monoatomic particles interacting with Lennard-Jones interactions. The molecular model construction has been described in Chapter 14. 

Practice working with your Learning By Modeling software Construct molecular models of ethane ethylene and acetylene and compare them with respect to their geometry bond angles and C—H and C—C bond distances... 

Draw or construct a molecular model of the most stable confor... 

Construct a molecular model of the product formed by catalytic hydrogenation of 1 2 dimethylcyclohexene Assume syn addition occurs... 

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" ... 

Given the molecular formula CgHnBr construct a molecular model of the isomer that is a pnmary alkyl bromide yet relatively unreactive toward bimolecular nucleophilic substitution... 

Cyclohexyl bromide is less reactive than noncychc secondary alkyl halides toward 8 2 sub stitution Construct a molecular model of cyclohexyl bromide and suggest a reason for its low reactivity... 

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... 

Intramolecular hydrogen bonding is present in the chiral diastereomer of 225 5 tetra methylhexane 3 4 diol but absent in the meso diastereomer Construct molecular models of each and suggest a reason for the difference between the two... 

Construct a molecular model of trans 2 bromocyclohexanol in its most stable conformation This conformation is ill suited to undergo epoxide formation on treatment with base Why2 What must happen in order to produce 1 2 epoxycyclohexane from trans 2 bromocyclohexanoP... 

Construct a molecular model of threo 3 bromo 2 butanol What is the stereochemistry (cis or trans) of the 2 3 epoxybutane formed on treatment of threo 3 bromo 2 butanol with base" Repeat the exercise for erythro 3 bromo 2 butanol... 

Construct a molecular model of cyclohexanone Do either of the hydrogens of C 2 eclipse the carbonyl oxygen" ... 

Excluding enantiomers there are three isomeric cyclopropanedicarboxyhc acids Two of them A and B are constitutional isomers of each other and each forms a cyclic anhydnde on being heated The third diacid C does not form a cyclic anhydride C is a constitutional isomer of A and a stereoisomer of B Identify A B and C Construct molecular models of the cyclic anhy dndes formed on heating A and B Why doesn t C form a cyclic anhydride" ... 

The biological properties of dioxin include an ability to bind to a protein known as the AH (aromatic hydrocarbon) receptor Dioxin IS not a hydrocarbon but it shares a certain structural property with aromatic hydrocarbons Try constructing molecular models of dioxin and anthracene to see these similarities... 

The compound shown is diethylstilbestrol (DES) it has a number of therapeutic uses in estrogen replacement therapy DES is not a steroid but can adopt a shape that allows it to mimic estrogens such as estradiol (p 1100) and bind to the same receptor sites Construct molecular models of DES and estradiol that illustrate this similanty in molecular size shape and location of polar groups... 

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