Syntheses and Structures of Hypervalent Pentacoordinate
Carbon and Boron Compounds Bearing an Anthracene
Skeleton − Elucidation of Hypervalent Interaction Based on
X-ray Analysis and DFT Calculation
Makoto Yamashita
Yohsuke Yamamoto
Kin-ya Akiba
Daisuke Hashizume
Fujiko Iwasaki
Nozomi Takagi
Shigeru Nagase
10.1021/ja0438011.s003
https://acs.figshare.com/articles/dataset/Syntheses_and_Structures_of_Hypervalent_Pentacoordinate_Carbon_and_Boron_Compounds_Bearing_an_Anthracene_Skeleton_Elucidation_of_Hypervalent_Interaction_Based_on_X_ray_Analysis_and_DFT_Calculation/3294031
Pentacoordinate and tetracoordinate carbon and boron compounds (<b>27</b>, <b>38</b>, <b>50</b><b>−</b><b>52</b>, <b>56</b><b>−</b><b>61</b>)
bearing an anthracene skeleton with two oxygen or nitrogen atoms at the 1,8-positions were synthesized
by the use of four newly synthesized tridentate ligand precursors. Several carbon and boron compounds
were characterized by X-ray crystallographic analysis, showing that compounds <b>27</b>, <b>56</b><b>−</b><b>59</b> bearing an
oxygen-donating anthracene skeleton had a trigonal bipyramidal (TBP) pentacoordinate structure with
relatively long apical distances (ca. 2.38−2.46 Å). Despite the relatively long apical distances, DFT calculation
of carbon species <b>27</b> and boron species <b>56</b> and experimental accurate X-ray electron density distribution
analysis of <b>56</b> supported the existence of the apical hypervalent bond even though the nature of the
hypervalent interaction between the central carbon (or boron) and the donating oxygen atom was relatively
weak and ionic. On the other hand, X-ray analysis of compounds <b>50</b><b>−</b><b>52</b> bearing a nitrogen-donating
anthracene skeleton showed unsymmetrical tetracoordinate carbon or boron atom with coordination by
only one of the two nitrogen-donating groups. It is interesting to note that, with an oxygen-donating skeleton,
the compound <b>61</b> having two chlorine atoms on the central boron atom showed a tetracoordinate structure,
although the corresponding compound <b>60</b> with two fluorine atoms showed a pentacoordinate structure.
The B−O distances (av 2.29 Å) in <b>60</b> were relatively short in comparison with those (av 2.44 Å) in <b>59</b>
having two methoxy groups on the central boron atom, indicating that the B−O interaction became stronger
due to the electron-withdrawing nature of the fluorine atoms.
2005-03-30 00:00:00
skeleton
DFT Calculation Pentacoordinate
pentacoordinate structure
Boron Compounds Bearing
boron species 56
TBP
unsymmetrical tetracoordinate carbon
boron atom
anthracene
apical distances
Hypervalent Pentacoordinate Carbon
apical hypervalent bond
tridentate ligand precursors
carbon species 27
fluorine atoms
boron compounds
analysis