17.12.2020 Halogen Bond in Crystal Engineering: Structural Studies on Crystals with Ruthenium Centered Complexes and 1-(4-Pyridyl)-4-thiopyridine Zwitterion as Halogen Bond Acceptors (Xin)

Halogen bond, one of the noncovalent interactions, has been recognized as a prominent tool in crystal engineering due to its strong directionality and strength. This work focuses on using both [Ru(bpy)(CO)2X2] (X=Cl, Br, I) and a newly synthesized organic zwitterion, 1-(4-pyridyl)-thiopyridine (PTP), as halogen bond acceptors to construct a series of crystal structures and to investigate the selectivity of halogen bond.
Published
17.12.2020

Three crystals were obtained from co-crystallization of [Ru(bpy)(CO)2X2] (X=Cl, Br, I) and p-diiodotetrafluorobenzene (p-DITFB). Of these three crystals, [Ru(bpy)(CO)2Cl2]·p-DITFB and [Ru(bpy)(CO)2Br2]·p-DITFB are isomorphic, with both halido ligands involved in halogen bond, forming zig-zag chains, expanding into 3D network with solvent accommodating voids. [Ru(bpy)(CO)2I2]·p-DITFB forms linear chains with only one of the two iodo ligands participating in halogen bond formation. The neighboring linear chains are linked together via FO interactions to form 3D networks without voids large enough for solvent molecules.

The selectivity of halogen bond between S and N in sulfur coordinate thiocyanate ligand of [Ru(bpy)(CO)2(S-NCS)2] was studied with I2 as the halogen bond donor. The computational analyses have revealed that both NCSI and SCNI system are energetically feasible, despite the fact that the more sterically hindered NCSI is the only experimentally obtained one, suggesting the dominant role of packing effect.

The new halogen bond acceptor, PTP, has both bidentate sp3-S and monodentate sp2-N, enabling constructing crystals with higher dimensions without losing controllability. Interacting with p-DITFB, PTP yielded a wavy 2D network via halogen bond. Moreover, both the DSC measurements and Hirschfeld surface analyses indicate the pivotal role of other non-covalent interactions in the arrangement of molecules.

Clearly, halogen bond is an effective tool in crystal engineering, however, other non-covalent interactions have to be accounted as well. The challenge lays in the predication of the dominant non-covalent interaction, which obstruct the controllability of supramolecular construction.

The reseach is published in JYU Dissertation series, number 323, Ģֱ, Jyväskylä , 2020.
ISBN 978-951-39-8420-5 (PDF) URN:ISBN:978-951-39-8420-5 ISSN 2489-90
Link to publication:

For further information:
M.Sc. Xin Ding, xin.x.ding@jyu.fi

M.Sc. Xin Ding defends his doctoral dissertation in Chemistry "Halogen Bond in Crystal Engineering: Structural Studies on Crystals with Ruthenium Centered Complexes and 1-(4-Pyridyl)-4-thiopyridine Zwitterion as Halogen Bond Acceptors" in 17 th of December 2020 at the Ģֱ starting at 12 noon. Opponent is Associate Professor Dominik Cinčić  from the University of Zagreb (Croatia) and Custos is Professor Matti Haukka  from the Ģֱ. The doctoral dissertation is held in English.

The audience can follow the dissertation online.
Link to the Zoom Webinar (Zoom application or Google Chrome web browser recommended):

Phone number to which the audience can present possible additional questions at the end of the event (to the custos): +358408054666