Versatility in Complexation of Six-Membered Heterocyclic Guests by Singly Bridged Triarylmethanol Hosts. X-Ray Crystal Structures and Thermal Stabilities of Inclusion Compounds with Piperidine, Thioxane/Dioxane, and Morpholine

Abstract

9-Phenylfluoren-9-ol (1), 2,7-dibromo-9-phenylfluoren-9-ol (2), and 9-phenylethynylfluoren-9-ol (3) enclathrate different six-membered heterocyclic guests involving piperidine, thioxane, dioxane, and morpholine. X-Ray crystal structure determinations of corresponding inclusion compounds [1·piperidine (1 : 1), 1·thioxane·dioxane (2 : 2 : 1), 2·morpholine (1 : 2), and 3·morpholine (1 : 1)] are reported, showing remarkable variety in the packing relations. Host compound 1 forms H-bonded 1 : 1 host : guest units with both piperidine and thioxane, but in the latter case additional dioxane guests are incorporated in the crystal, thus yielding a ternary complex. Host compound 3 is capable of forming closed loops of hydrogen bonds with full hydrogen bond saturation in its inclusion compound with morpholine, whereas in the related morpholine complex of 2 H-bonded 1 : 2 associates are created without maximal saturation of the hydrogen bonds, and with different binding modes for the two guests of the stoichiometric unit. In the crystals, the various H-bonded host-guest units are linked together by Van der Waals’ forces, occasionally supported by weak electrostatic interactions. The stabilities of the four different inclusion compounds were studied by thermal analysis indicating complex decomposition modes.

Temperature-dependent phase transition in a phenylfluorenol inclusion compound

“…5 It also enclathrates piperidine (H : G 1 : 1) and forms a mixed guest inclusion compound with thioxane and dioxane (H : G 1 : G 2 2 : 2 : 1). 6 The structure of the apohost, grown from light petroleum, is built of hydrogen-bonded dimers, while its methyl-analogue, 9-methylfluoren-9-ol, remarkably packs as hydrogen-bonded tetramers. 7 As part of a systematic study of the structures of fluorenol hosts with amines, we have elucidated the structure of this host with 4-methylcyclohexylamine (TMC), and have noted a temperature-dependent phase transition.…”

Wechselwirkungen in Molekülkristallen, 149 [1 -3]. Wirt/Gast-Einschlußverbindungen von NjN'-Ditosyl-p-phenylendiamin: Die Wasserstoffbrücken-Addukte mit Morpholin; Pyridin, N,N-Dimethylformamid und Dimethylsulfoxid / Interactions in Molecular Crystals, 149 [1 - 3]. Host/Guest-Inclusion Compounds of N,N'-Ditosyl-/?-phenylenediamine: The Hydrogen Bonded Adducts with Morpholine, Pyridine, N ,N -Dimethylform amide, and Dimethylsulfoxide

“…D er A m ino-W as serstoff steht axial, jedoch sollte das M orpholinKonform er m it äquatorialer H -Position energetisch etw a vergleichbar sein. Die Cam bridge Structural D atabase (Version 5.10) enthält lediglich vier K ri stallstrukturen mit M orpholin-M olekülen [16][17][18] und nur für die Einschlußverbindung mit 2,7-Dibrom -9-phenylfluoren-9-ol (Refcode: ZORVUX) sind die Koordinaten des A m ino-W asserstoffs an gegeben, nach denen ausschließlich das M orpholinKonform er m it äquatorialem A m ino-W asserstoff vorliegt [18]. D ichtefunktional-B erechnungen m it Basissätzen 6-31G* bis 6-31 IG ** für M orpholin in Sessel-K onform ation mit idealisierten W asser stoff-Positionen belegen, wie gering die E nergie unterschiede zw ischen beiden Konform eren sind (Gl.…”

“…In die hier analysierten K ristalle (Abb. 1) w er den selektiv zwei Äquivalente des Konform ers m it axialem A m ino-W asserstoff eingebaut, in die K ri stalle von 2,7-D ibrom -9-phenylfluoren-9-ols [18] dagegen zwei Ä quivalente des M orpholin-K onform ers mit äquatorialer A m ino-W asserstoff-Position. …”