Problem

# Numerous compounds containing central cubane structures, formally derived from the cubi...

Numerous compounds containing central cubane structures, formally derived from the cubic organic molecule cubane, C8H8 , have been prepared. The core structure typically have four metals at opposite corners of a distorted cube, with nonmetals such as O and S at the other corners, as shown (E = nonmetal).

In addition to cubanes in which all metals and nonmetals are identical, they have been prepared with more than one metal and/or more nonmetal in the central 8-atom core; attached groups on the outside may also vary.

a. How many isomers are possible if the core has the following formulas:

1. Mo3WO3S?

2. Mo3WO2S2?

3. CrMo2WO2SSe?

b. Assign the point groups for each isomer identified in part a.

c. Is it possible for the central 8-atom core of a cubane structure to be chiral? Explain.

#### Step-by-Step Solution

Solution 1

a.

Isomers for the are as shown below. There are two isomers are possible for this structure.

Isomers for the are as shown below. There are two isomers are possible for this structure.

Isomers for the are as shown below. There are four isomers are possible for this structure.

b.

Yes, provided the structure have no symmetry or only Cn axes. Examples are the structures with C1 symmetry in part a.

c.

No, the structure will not be chiral. This is because, the each central atom (E, M) are attached to the similar groups like E and M.

Solutions For Problems in Chapter 9
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