Enhanced and Heteromolecular Guest Encapsulation in Nonporous Crystals of a Perfluorinated Triketonato Dinuclear Copper Complex

Abstract

The flexible hostf ramework of ap erfluorinated mononuclear copper complex,[ Cu(L 1 ) 2 ]( 1,H L 1 = 3-hydroxy-1,3-bis(pentafluorophenyl)-2-propen-1-one), with aC uO 4 core reversibly encapsulateds everal organic guest molecules throughe lectrostatic interactions in its crystals. Hence, the correspondingd inuclearc omplex, [Cu 2 (L 2 ) 2 ]( 2,H 2 L 2 = 1,5-dihydroxy-1,5-bis(pentafluorophenyl)-1,4-pentadien-3-one), was prepared to enhanceg uest recognition and the ability to separate molecular mixtures. Complex 2 comprises a Cu 2 O 6 core and four pentafluorophenylg roups. In crystal 2, cavitiesa re formed on the axial sites of the metal core that are surroundedb yp entafluorophenylg roups.T he crystal of 2 encapsulates various guest molecules, that is, benzene (3), toluene (4), xylene (5), mesitylene (6), durene (7), and anisole (8). X-ray crystallographic and thermogravimetric (TG) studies show that three guest molecules are present in the crystal cavities. The number of guest molecules found in complex 2 was higher than that in complex 1,f or example, (2) 3 ·(6) 10 > 1·(6) 2 ,( 2) 2 ·(7) 7 > 1·7,o r2·(8) 3 > 1·(8) 2 .N aphthalene (9), was encapsulatedi n2 to give 2·(9) 3 ,b ut not in 1.I nt he crystal of complex 2,h eteromolecular guest encapsulation was confirmed, designated as 2·(3) 2 ·9.T Ga nalysis indicates that the thermals tabilityo ft he guest-included crystalso f2 is higher than that of 1. Figure 11. TG curves of guestrelease from 2·(3) 3 , 2·(9) 3 ,a nd 2·(3) 2 ·9.The scan rate was 5.0 8Cmin À1 .

Synthesis and Crystal Structures of Rhomb-Shaped Dimeric Pd(II) Complexes with Arylethynyl-Substituted 2,2′-Bipyridine through CH⋯π Interactions in the Crystalline States

“…The Pt 2+ [10] and Pd 2+ [11] centers of square-planar metal complexes can act as halogen-bond acceptors upon their interaction with σh-donating organohalides, and the complexes are co-crystallized with πh-donating perfluoroaromatic species giving the sandwich structures based on π-hole• • • π interactions [12,13] when the nucleophile metal center and electron-poor molecule are opposite charge distributions [14]. We reported that the supramolecular association of square-planar Pt 2+ , Pd 2+ , and Cu 2+ β-diketonate complexes [15,16], which nucleophile characteristics of Pt 2+ and Pd 2+ are clearly shown in the results of their crystal packings in the solid state and DFT calculations. The axial surface on the Pt 2+ center in complexes shows high negative ESP and nucleophile that on Pd 2+ center remarkably changed the surrounding substitutions, e.g., the negative value for [Pd(dbm) 2 ] and neutral~positive for the corresponding perfluorinated complex, [Pd(L) 2 ] (L = bis(pentafluorobenzoyl)methanido − ), indicating the possibility of strict adjustment of the metal characteristics [15].…”

Synthesis and π-Hole vs. π Effects of Pt(II) Complexes with Pentafluorophenyl and Phenyl-Substituted Bipyridines

“…The intricate behavior of charges induced by fluorine not only determines the intrinsic properties of molecules but also their behavior in a plethora of chemical reactions and applications, from organic electronics to pharmaceuticals [7][8][9]. In the realm of our research, we have delved into the study of aromatic fluorine compounds [10][11][12][13][14], a category known for its significant impact on chemical compounds due to the electron-withdrawing nature imparted by the fluorine substitutions. Aromatic fluorine molecules, exemplified by entities such as pentafluorophenyl groups [1,[15][16][17], and heterocyclic molecules like those containing triazine rings [18] are distinguished as π-hole molecules [19][20][21][22][23][24][25][26].…”

Cyanamides as π-Hole Donor Components of Structure-Directing (Cyanamide)···Arene Noncovalent Interactions

“…Intermolecular interactions involving hydrogen or p-block elements have been divided into two groups, based on the position of the region of electropositivity in the donating group . In a σ-hole (σh) donor, the electropositive site lies within the plane of the molecular framework, typically at the extension of a covalent bond; the electropositive region in π-hole (πh) donor lies perpendicular to the molecular plane. , A constantly growing part of recent reports is devoted to πh donors, which are involved in anion−π, , lone pair−π, − and π–π interactions. − These types of contacts are now widely utilized in crystal engineering, − catalysis, − materials science, − and chemical and biological recognition. − …”