Browsing by Author "Groeneman, Ryan H."
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Item Controlling thermal expansion within mixed cocrystals by tuning molecular motion capability(2020) Ding, Xiaodan (TTU); Unruh, Daniel K. (TTU); Groeneman, Ryan H.; Hutchins, Kristin M. (TTU)Controlling thermal expansion (TE) behaviors of organic materials is challenging because several mechanisms can govern TE, such as noncovalent interaction strength and structural motions. Here, we report the first demonstration of tuning TE within organic solids by using a mixed cocrystal approach. The mixed cocrystals contain three unique molecules, two of which are present in variable ratios. These two molecules either lack or exhibit the ability to undergo molecular motion in the solid state. Incorporation of higher ratios of motion-capable molecules results in larger, positive TE along the motion direction. Addition of a motion-incapable molecule affords solids that undergo less TE. Fine-tuned TE behavior was attained by systematically controlling the ratio of motion-capable and -incapable molecules in each solid.Item Controlling thermal expansion within mixed cocrystals by tuning molecular motion capability(2020) Ding, Xiaodan (TTU); Unruh, Daniel K. (TTU); Groeneman, Ryan H.; Hutchins, Kristin M. (TTU)Controlling thermal expansion (TE) behaviors of organic materials is challenging because several mechanisms can govern TE, such as noncovalent interaction strength and structural motions. Here, we report the first demonstration of tuning TE within organic solids by using a mixed cocrystal approach. The mixed cocrystals contain three unique molecules, two of which are present in variable ratios. These two molecules either lack or exhibit the ability to undergo molecular motion in the solid state. Incorporation of higher ratios of motion-capable molecules results in larger, positive TE along the motion direction. Addition of a motion-incapable molecule affords solids that undergo less TE. Fine-tuned TE behavior was attained by systematically controlling the ratio of motion-capable and-incapable molecules in each solid.Item Controlling topology within halogen-bonded networks by varying the regiochemistry of the cyclobutane-based nodes(2021) Dunning, Taylor J.; Unruh, Daniel K. (TTU); Bosch, Eric; Groeneman, Ryan H.The formation of a pair of extended networks sustained by halogen bonds based upon two regioisomers of a photoproduct, namely rctt-1,3-bis(4-pyridyl)-2,4-bis(phenyl)cyclobutane (ht-PP) and rctt-1,2-bis(4-pyridyl)-3,4-bis(phenyl)cyclobutane (hh-PP), that have varied topology is reported. These networks are held together via I· · · N halogen bonds between the photoproduct and the halogen-bond donor 1,4-diiodoperchlorobenzene (C6 I2 Cl4). The observed topology in each solid is controlled by the regiochemical position of the halogen-bond accepting 4-pyridyl group. This paper demonstrates the ability to vary the topology of molecular networks by altering the position of the halogen bond acceptor within the cyclobutane-based node.Item Halogen-bonded co-crystal containing 1,3-diiodo-perchlorobenzene and the photoproduct rtct-tetrakis(pyridin-4-yl)cyclobutane resulting in a zigzag topology(2023) Bosch, Eric; Unruh, Daniel K. (TTU); Santana, Carlos L.; Groeneman, Ryan H.The formation and crystal structure of a zigzag network held together by I• • •N halogen bonds is reported. In particular, the halogen-bond donor is 1,3-diiodoperchlorobenzene (C6I2Cl4) while the acceptor is the photoproduct rtct-tetrakis(pyridin-4-yl)cyclobutane (TPCB). Curiously, within the resulting co-crystal (C6I2Cl4)•(TPCB), the photoproduct accepts only two halogen bonds between neighbouring 4-pyridyl rings and as a result behaves as a bent two-connected node rather than the expected four-connected centre. In addition, the photoproduct, TPCB, is also found to engage in C—H• • •N hydrogen bonds, forming an extended zigzag chain.