Title: In Silico Prediction of Structural Properties of a Racemic Porous Organic Cage Crystal

Abstract

Porous organic cage (POC) solids are porous materials made up of individual porous molecules held together by noncovalent forces. While many examples of POCs have been made in homochiral forms (i.e., crystals in which every molecule has the same chirality), crystallization of POCs that contain mixtures of chiral molecules can also yield useful properties. For example, our previous work has demonstrated that a POC crystal [cage crystal 3 (CC3)-racemic] synthesized using a racemic mixture of diaminocyclohexane has improved sorption properties and stability than a similar POC crystal synthesized with homochiral diaminocyclohexane. The main purpose of this paper is to predict the structure of CC3-racemic with atomic detail because it is challenging to fully resolve the structure of this racemic crystal experimentally since only subtle differences exist between the racemic structure and the known crystal structure of homochiral CC3. Here, we introduce an in silico prediction method that combines electronic structure calculations and atomistic calculations to predict the structure of CC3-racemic. We first enumerate types of cage molecules that can be present in this material and establish their concentrations. A key observation from these calculations is that CC3-racemic is not made up of only CC3-R and CC3-S molecules and that anmore » additional class of heterochiral cages is also present. By studying the packing energy of cage pairs in CC3-racemic, a lattice model representation of the racemic crystal is developed and used in MC simulations to assess the structure of extended crystals. By expanding the lattice model into atomic detail, fully detailed CC3-racemic crystal models are obtained. These models provide the most thorough description available to date of the composition and cage packing of this interesting material.« less

Authors:

Liu, Yang ^[1]; Zhu, Guanghui ^[1]; You, Wenqin ^[1]; Tang, Hongjian ^[2]; Jones, Christopher W. ^[1]; Lively, Ryan P.  ^[1];

• Search DOE PAGES for author "Lively, Ryan P."
• Search DOE PAGES for ORCID "0000-0002-8039-4008"

Sholl, David S.  ^[1]

• Search DOE PAGES for author "Sholl, David S."
• Search DOE PAGES for ORCID "0000-0002-2771-9168"

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+ Show Author Affiliations

1. Georgia Inst. of Technology, Atlanta, GA (United States)
2. Georgia Inst. of Technology, Atlanta, GA (United States); Southeast Univ., Jiangsu (China)

Publication Date:

Thu Dec 20 00:00:00 EST 2018

Research Org.:

Univ. of Texas, Austin, TX (United States). Energy Frontier Research Center (EFRC); Georgia Institute of Technology, Atlanta, GA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); Dow Chemical Company

OSTI Identifier:

1566521

Grant/Contract Number:  

SC0012577

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Physical Chemistry. C

Additional Journal Information:

Journal Volume: 123; Journal Issue: 3; Journal ID: ISSN 1932-7447

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (heterogeneous); defects; membrane; carbon capture; materials and chemistry by design; synthesis (novel materials); synthesis (self-assembly); synthesis (scalable processing)