Related Experiment Video
Updated: Aug 24, 2026

Production, Crystallization and Structure Determination of C. difficile PPEP-1 via Microseeding and Zinc-SAD
Published on: December 30, 2016
Packing conflicts in the Z' = 5 structure of CF(3)(CF(2))(3)(CH(2))(10)COOH
Hans Joachim Lehmler1, Sean Parkin, Carolyn Pratt Brock
1Department of Occupational and Environmental Health,100 Oakdale Campus, 124 IREH, The University of Iowa, Iowa City, IA 52242-5000, USA.
Abstract:
Dimers of the partially fluorinated amphiphile 1-(perfluorobutyl)undecanoic acid, CF(3)(CF(2))(3)(CH(2))(10)COOH, crystallize in the same basic packing arrangement found for many n-alkyl carboxylic acids. The unit cell of the fluorinated compound, however, contains five independent molecules rather than the one found for most n-alkyl carboxylic acids including CH(3)(CH(2))(13)COOH. The structures of the two C(15) acids are compared. The structural modulations that lead to the large value of Z' can be understood as resulting from the conflict between the necessity of filling space densely and uniformly and the tendency of unlike groups to be segregated spatially. The few other known structures of compounds with both (CF(2))(n) and (CH(2))(m) regions show evidence of the same conflict.
Related Concept Videos
Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Conformations of Cyclohexane
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
Chair Conformation of Cyclohexane
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
Preparation of Amides
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
Fischer Projections
Carboxylic Acids to Acid Chlorides

