Chapter 2 Multiple Choice Questions

. Which of the following host molecules is likely to bind Cs+ most strongly in acetonitrile?

. Which of the following guest molecules is likely to be most strongly bound by this host complex in DMSO?

The structure of a compound has a nine-carbon chain, in which C 2 and C 8 are replaced by an N H group. C 5 is replaced by a nitrogen atom. C 1 and C 9 each is bonded to C 1 of a benzene ring. C 4 of the benzene ring is bonded to a C H 2 group, which is further bonded to a methoxy group. The carbon of each methoxy group is bonded to a common benzene ring at C 2 and C 4 forming a closed ring cavity system. C 2, C 4, and C 6 are bonded to an ethyl group. N 5 is bonded to a four-carbon chain, in which C 3 is replaced by an N H group. C 4 is bonded to C 1 of a benzene ring, in which C 4 is bonded to a C H 2 group. The C H 2 group is bonded to a methoxy group, which is bonded to C 3 of the benzene ring with three ethyl groups forming a bicyclo system.

. Cucurbit[7]uril is expected to have the highest affinity in water for which of the following compounds?

. In the early 2000s, the first example of an anion-templated self-assembly of a threaded complex between a bis-amide containing macrocycle and a bis-amide linear molecule was reported. The resulting complex, termed a pseudorotaxane, was stable enough to be characterized by solid-state crystallography, and has the structure as shown below:

The structure of a compound has a 13-carbon chain, in which C 1, C 4, C 7, C 10, and C 13 are replaced by an oxygen atom. O 1 and O 13 each is bonded to a benzene ring, which is bonded to an oxygen atom. The oxygen atom is bonded to C 1 of a two-carbon chain, in which C 2 is boded to an N H group. The N H group is bonded to a carbon atom, which is double-bonded to an oxygen atom and single bonded to a common benzene ring forming a closed ring cavity system. The cavity is occupied by an anion A superscript negative charge. The cavity also traps a compound, which has a benzene ring. C 1 of the benzene ring is replaced by a nitrogen atom carrying an appositive charge and bonded to a methyl group. C 3 and C 5 each is bonded to a carbon atom, which is double-bonded to an oxygen atom and single-bonded to an N H group. Each N H group is bonded to a six-carbon chain.

Which of the following anions (A-), when occupying the space in between the four amide linkages, is likely to form the most stable pseudorotaxane? Assume that all anions can fit into the binding site highlighted in grey.

. 1H NMR titrations were performed on the halogen bonding receptor shown below in d6-DMSO, where increasing quantities of tetrabutylammonium chloride were added to a solution of the receptor. In the presence of 1.0 equivalent of salt, large downfield shifts (+0.5 ppm) were observed for the resonance from proton A, while small downfield shifts were seen for those from protons B and C (< +0.1 ppm).

The structure of a compound has a benzene ring, in which C 1 and C 3 are bonded to C 5 of a cyclopentane ring. C 1, C 2, and C 3 are replaced by a nitrogen atom. N 1 carries a positive charge, single bonded to a methyl group, and double-bonded to N 2. The N 2 is bonded to N 3, which is further bonded to a six-carbon chain. C 4 is double-bonded to C 5 and single bonded to an iodine atom. The hydrogen atoms bonded to C 2 of the benzene ring are labeled A. The hydrogen atoms bonded to C 6 of the benzene ring are labeled B. The hydrogen atoms of the methyl group bonded to the nitrogen atom are labeled C.

Which of the following receptor-chloride binding scenarios is most consistent with the NMR titration data?

. The heteroditopic receptor shown below can bind an anion by its urea motif, whose anion binding affinity can be increased by the presence of an alkali metal salt (MBPh4).

The structure of a compound has a central carbon atom, which is double-bonded to an oxygen atom, single bonded to an N H group on the right, and another N H group on the left. The N H group on the left is bonded to a benzene ring. The N H group on the right is bonded to a 15-carbon ring system, in which C 1, C 4, C 7, C 10, and C 13 are replaced by an oxygen atom.

For which of the following combinations of anion and M+ is likely to give the largest binding constant for the anion in acetonitrile solution?

. Which of the following macrocycles is expected to increase the solubility of LiPF6 most in dichloromethane?

. Chloride was added to each of the following receptors 1-4 in acetonitrile.

(1) The structure of a compound has a benzene ring, in which C 4 and C 6 are bonded to a hydroxyl group. C 1 and C 3 each is bonded to a carbon atom, which is double-bonded to an oxygen atom and single-bonded to an N H group that is further bonded to a five-carbon chain.(2) The structure of a compound has a benzene ring, in which C 1 and C 3 is bonded to C 5 of a cyclopentane ring. C 1, C 2, and C 3 are replaced by a nitrogen atom. N 1 carries a positive charge, single bonded to a methyl group, and double-bonded to N 2. The N 2 is bonded to N 3. C 4 is double-bonded to C 5. N 3 bonded to the terminal carbon atoms of a 13-carbon chain forming a ring cavity system.(3) The structure of a compound has a benzene ring, in which C 1 and C 3 each is bonded to a carbon atom, which is double-bonded to an oxygen atom and single-bonded to an N H group that is further bonded to a five-carbon chain.(4) The structure of a compound has a benzene ring, in which C 4 and C 6 are bonded to a methoxy group. C 1 and C 3 each is bonded to a carbon atom, which is double-bonded to an oxygen atom and single-bonded to an N H group that is further bonded to a five-carbon chain.

Arrange the receptors in increasing order of chloride binding affinities (I.e. lowest to highest affinity).

. Consider the following reaction:

An illustration depicts a chemical reaction, in which two reactants react in the presence of an unknown reagent, T H F, and heat to yield the product. The structure of the first reactant has a benzene ring, in which C 1 and C 2 are bonded to a hydroxyl group. The structure of the second reactant has eight repeating units of an organic group, which has a two-carbon chain, in which C 1 is bonded to a terminal oxygen atom. The terminal C 2 of the repeating unit is bonded to an O T s group. The terminal oxygen atom is bonded to a tosyl group, T s. The structure of the product has a 27-carbon closed ring cavity, in which C 1, C 4, C 7, C 10, C 13, C 16, C 19, C 22, and C 25 are replaced by an oxygen atom. C 2 and C 3 are fused to a common benzene ring.

Which of the following reagents is likely to give the highest yield of the target benzo-crown ether macrocycle?

. The following receptor was designed to bind and sense cations by fluorescence spectroscopy. Which of the following cations is the receptor likely to be selective for?

The structure of a compound has a 15-carbon chain, in which C 1 is replaced by a nitrogen atom. C 4, C 7, C 10, and C 13 are replaced by a sulfur atom. N 1 is bonded to a benzene ring, which is further bonded to C 4 of a cyclohexane ring. C 1 of the cyclohexane ring is replaced by an oxygen atom and C 3 is double bonded to C 4. The cyclohexane ring is fused to a phenol ring on the right and a cyclohexadienone ring on the right.

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