Mono‑,
Di‑, and Triborylphosphine Analogues
of Triarylphosphines
Jonathan
A. Bailey
Marten Ploeger
Paul G. Pringle
10.1021/ic501133n.s001
https://acs.figshare.com/articles/journal_contribution/Mono_Di_and_Triborylphosphine_Analogues_of_Triarylphosphines/2272804
Diazaborinylphosphines
based on the 1,8-diaminonaphthylboronamide
heterocycle are prepared by a chlorosilane-elimination reaction, and
their structural and bonding properties are compared to those of PPh<sub>3</sub>. The precursor chloroborane ClB{1,8-(NH)<sub>2</sub>C<sub>10</sub>H<sub>6</sub>} (<b>I</b>) is fully characterized including
its crystal structure, which features intermolecular π–π
stacking, B···N interactions, and N–H···Cl
hydrogen bonding. Treatment of <b>I</b> with Ph<sub>3–<i>n</i></sub>P(SiMe<sub>3</sub>)<sub><i>n</i></sub> gave
the corresponding Ph<sub>3–<i>n</i></sub>P(B{1,8-(NH)<sub>2</sub>C<sub>10</sub>H<sub>6</sub>})<sub><i>n</i></sub>, {<b>L</b><sub><b>1</b></sub> (<i>n</i> =
1), <b>L</b><sub><b>2</b></sub> (<i>n</i> =
2), and <b>L</b><sub><b>3</b></sub> (<i>n</i> = 3)}. The crystal structures of <b>L</b><sub><b>1</b>–<b>3</b></sub> reveal an increase in the planarity
at P as a function of <i>n</i>, and the steric bulk of the
diazaborinyl substituent B{1,8-(NH)<sub>2</sub>C<sub>10</sub>H<sub>6</sub>} is similar to that of a phenyl. Nucleus-independent chemical
shift calculations were carried out that suggest that the 14 π-electron
diazaborinyl substituent can be described as aromatic overall, though
the BN<sub>2</sub>-containing ring is slightly antiaromatic. The complexes <i>cis-</i>[Mo(<b>L</b><sub><b>1</b>–<b>3</b></sub>)<sub>2</sub>(CO)<sub>4</sub>] (<b>1</b>–<b>3</b>) are prepared from [Mo(nbd)(CO)<sub>4</sub>] (nbd = norbornadiene)
and <b>L</b><sub><b>1</b>–<b>3</b></sub>.
From the position of the ν(CO) (<i>A</i><sub>1</sub>) band in the IR spectra of <b>1</b>–<b>3</b>,
it is deduced that the diazaborinyl substituent has a donating capacity
similar to an alkyl group.
2014-07-21 00:00:00
BN
L 3
L 1
IR spectra
PPh 3.
CO
diazaborinyl substituent
crystal structure
crystal structures
alkyl group
Triborylphosphine Analogues
steric bulk