Recent Advances in Single-Crystal-to-Single-Crystal Transformation at the Discrete Molecular Level

Abstract

The present review focuses on the solid state structural transformations in discrete molecules. Since the molecules in the crystal lattice are closely packed, any transformation in the solid state is difficult due to restricted movement of the molecules. These transformations can be triggered by external stimuli, such as light, heat, uptake or exchange of solvent, mechanochemical force, etc. which may be observed by a change in their physical properties like color, magnetism, porosity, and optical. Single-crystal-to-single-crystal (SCSC) transformations in metal−organic frameworks and coordination polymers are well documented; however, reports on SCSC transformations at the discrete molecular level still remain scarce. In this review, we have compiled some interesting examples from the literature on SCSC transformation at the discrete molecular level using various external stimuli.

Overcoming the Inertness of Iridium(III) in a Facile Single‐Crystal to Single‐Crystal Reaction of Iodine Vapor with a Cyclometalated Chloride Monomer

“…Direct observations of chemical reaction intermediates are very desirable as they provide crucial information about the reaction mechanisms that is especially important for catalytic processes . Single‐crystal to single‐crystal (SCSC) reactions, in combination with X‐ray diffraction analysis, are a very powerful tool to obtain comprehensive structural data on chemical species involved in the reactions, and to give insights into the dynamics of their mutual transformations . Still, for discrete molecular organometallic complexes, SCSC reactions involving ligand exchange are rare, because the formation or cleavage of metal‐ligand bonds is usually accompanied by the loss of crystallinity …”

“…[1][2][3] Single-crystal to single-crystal (SCSC) reactions, in combination with X-ray diffraction analysis, are av ery powerful tool to obtain comprehensive structurald ata on chemical species involved in the reactions, and to give insights into the dynamics of their mutual transformations. [4][5][6][7][8] Still, for discrete molecular organometallic complexes, SCSC reactions involving ligand exchange are rare, [9][10][11][12][13][14][15][16] because the formationo rc leavage of metal-ligand bonds is usually accompanied by the loss of crystallinity. [17] Cyclometalated iridium(III) complexes have found numerous applicationsi nd iverse fields of chemistry and optoelectronics due to their unique photophysical and electrochemical properties, as well as their exceptional thermodynamic and kinetic stability.…”

“…Among other small molecular chemicals, [27] iodine provedt o be most suitable to check our hypothesis because it has ar elatively high vapor pressure at room temperature, [28] forms strong halogen bonds [29] and, as it later turnedo ut, does not destroyt he crystal packing of 1.S ingle crystalso fc omplex 1 were exposed to iodine vapor for 30 min (2), two hours (3), six hours (4), and24h ours (5)(Scheme 1). The color of the crystals gradually changed from red (1)t hrough light-(2)a nd darkbrown (3)tocompletely black (4,5). Structural study of crystals 2-5 visualized the dynamics of an unprecedentedg as-solid reaction of iodine vapor with complex 1.…”

Temperature-induced solid-to-solid transformation in helical homochiral coordination polymers

“…Therefore, the helical structure has always been a focus in chemistry and biology. Homochiral CPs are usually synthesized by the self-assembly of bridging chiral ligands and metal ions or clusters in the solution phase (Yoon et al, 2012;Mo et al, 2014;Jiao et al, 2016;Yue et al, 2016;Chaudhary et al, 2017;Hu et al, 2017;Liu et al, 2015). Homochiral CPs are usually synthesized by the self-assembly of bridging chiral ligands and metal ions or clusters in the solution phase (Yoon et al, 2012;Mo et al, 2014;Jiao et al, 2016;Yue et al, 2016;Chaudhary et al, 2017;Hu et al, 2017;Liu et al, 2015).…”

In situlaser irradiation setup for a Bruker three-circle goniometer

“…Such studies provide ample information about photochemical processes in the solid state, be it about light-induced chemical transformations (Chaudhary et al, 2017), structures of exited states (Raithby, 2015;Hatcher & Raithby, 2013) or spin-crossover phase transitions (Lé tard et al, 2012). To the best of our knowledge in the vast majority of such studies, especially those related to timeresolved crystallography, synchrotron sources were used (Fullagar et al, 2000).…”