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Fluorene Derivatives Bearing Halogenomethyl Groups: Synthesis, Molecular Structures, and Halogen/Hydrogen Bonding Patterns in the Crystalline State
Author(s) -
Seidel Pierre,
Schwarzer Anke,
Mazik Monika
Publication year - 2019
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201801621
Subject(s) - chemistry , synthon , fluorene , halogen bond , molecule , crystallography , crystal structure , halogen , supramolecular chemistry , hydrogen bond , intermolecular force , crystal engineering , non covalent interactions , stereochemistry , organic chemistry , polymer , alkyl
9,9‐Diethylfluorenes bearing chloromethyl, bromomethyl, and iodomethyl groups in the 2, 4, and 7 positions of the aromatic skeleton were prepared and their solid‐state structures determined by single‐crystal X‐ray diffraction analysis. The prepared fluorenes represent not only valuable starting materials for a wide range of fluorene‐based compounds but are also interesting objects for the analysis of the supramolecular motifs in the crystalline state. The X‐ray diffraction experiments revealed that the asymmetric unit of each structure contains one molecule, featuring similar conformations, but differ in their modes of non‐covalent intermolecular bonding. The crystal structures of the chloromethyl and bromomethyl substituted compounds 1 and 2 are primarily stabilized by Hal ··· Hal and C–H ··· Hal contacts, whereas the packing of the iodine substituted analogous compound 3 is influenced by triangular I 3 synthons, C–H ··· π interactions and to a less degree by C–H ··· I contacts. The manuscript provides information about new synthetic routes, new molecules as well as about halogen/hydrogen bonding patterns and other noncovalent interactions in the crystalline state. Concerning the syntheses, the efficient one‐step synthesis of 9,9‐diethylfluorene‐2,4,7‐tricarbaldehyde ( 8 ) is also worthy of particular mention.