Chapter 8
Relationship Between Atomic Contact
and Intermolecular Interactions:
Significant Importance of Dispersion
Interactions Between Molecules Without
Short Atom–Atom Contact in Crystals
Seiji Tsuzuki
Abstract Intermolecular interactions in crystals of polycyclic aromatic molecules,
n-hexane, and hexamine were analyzed by dispersion-corrected DFT calculations.
The origin of the attraction and the relationship between short atom–atom contact and
magnitude of attraction were discussed. The calculations show that the dispersion
interactions are the primary source of the attraction between adjacent molecules
in the crystals. The strong attraction by the dispersion interactions often exists
between adjacent molecules in the crystals, even if the adjacent molecules do not
have short atom–atom contact. Although intermolecular interactions in crystals have
been discussed based on the presence or absence of atom–atom contact at short
distances, our analysis shows that it is often dangerous to discuss the intermolecular
interactions in crystals solely based on crystal structures.
Keywords Intermolecular interaction · DFT calculations · Dispersion interaction ·
Short atom–atom contact · Crystal structure
8.1 Introduction
The intermolecular interactions control the arrangement of molecules in organic
crystals and greatly affect the physicochemical properties of the organic crystals.
For this reason, detailed information on intermolecular interactions is increasingly
required in the development of organic materials. With regard to the structures of
organic crystals, a huge amount of data obtained by crystal structure analysis has
been accumulated. On the other hand, it is not easy to directly elucidate the nature
(magnitude, directionality and origin of attraction) of the intermolecular interactions between molecules in crystals solely by experimental methods. For this reason,
until now, intermolecular interactions in organic crystals have often been discussed
S. Tsuzuki (B)
National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568, Ibaraki,
Japan
e-mail: s.tsuzuki@aist.go.jp
© Springer Nature Singapore Pte Ltd. 2020
M. Sakamoto and H. Uekusa (eds.), Advances in Organic Crystal Chemistry,
https://doi.org/10.1007/978-981-15-5085-0_8
137
Relationship Between Atomic Contact
and Intermolecular Interactions:
Significant Importance of Dispersion
Interactions Between Molecules Without
Short Atom–Atom Contact in Crystals
Seiji Tsuzuki
Abstract Intermolecular interactions in crystals of polycyclic aromatic molecules,
n-hexane, and hexamine were analyzed by dispersion-corrected DFT calculations.
The origin of the attraction and the relationship between short atom–atom contact and
magnitude of attraction were discussed. The calculations show that the dispersion
interactions are the primary source of the attraction between adjacent molecules
in the crystals. The strong attraction by the dispersion interactions often exists
between adjacent molecules in the crystals, even if the adjacent molecules do not
have short atom–atom contact. Although intermolecular interactions in crystals have
been discussed based on the presence or absence of atom–atom contact at short
distances, our analysis shows that it is often dangerous to discuss the intermolecular
interactions in crystals solely based on crystal structures.
Keywords Intermolecular interaction · DFT calculations · Dispersion interaction ·
Short atom–atom contact · Crystal structure
8.1 Introduction
The intermolecular interactions control the arrangement of molecules in organic
crystals and greatly affect the physicochemical properties of the organic crystals.
For this reason, detailed information on intermolecular interactions is increasingly
required in the development of organic materials. With regard to the structures of
organic crystals, a huge amount of data obtained by crystal structure analysis has
been accumulated. On the other hand, it is not easy to directly elucidate the nature
(magnitude, directionality and origin of attraction) of the intermolecular interactions between molecules in crystals solely by experimental methods. For this reason,
until now, intermolecular interactions in organic crystals have often been discussed
S. Tsuzuki (B)
National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568, Ibaraki,
Japan
e-mail: s.tsuzuki@aist.go.jp
© Springer Nature Singapore Pte Ltd. 2020
M. Sakamoto and H. Uekusa (eds.), Advances in Organic Crystal Chemistry,
https://doi.org/10.1007/978-981-15-5085-0_8
137