10.1021/acs.inorgchem.5b00414.s004
Kuanysh Z. Kabytaev
Kuanysh Z.
Kabytaev
Alexander
V. Safronov
Alexander
V.
Safronov
Yulia V. Sevryugina
Yulia V.
Sevryugina
Charles L. Barnes
Charles L.
Barnes
Satish S. Jalisatgi
Satish S.
Jalisatgi
M. Frederick Hawthorne
M. Frederick
Hawthorne
Novel Synthetic Approach to Charge-Compensated Phosphonio-<i>nido</i>-Carboranes. Synthesis and Structural Characterization
of Neutral Mono and Bis(Phosphonio) <i>nido</i>-<i>ortho</i>-Carboranes
American Chemical Society
2015
PPh 3
multinuclear NMR spectroscopy
Cs 2CO NaH
Pd
presence
compounds 2 c
tetrabutylammonium
phosphine substitution product
diiodo
iodo
2015-04-20 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Novel_Synthetic_Approach_to_Charge_Compensated_Phosphonio_i_nido_i_Carboranes_Synthesis_and_Structural_Characterization_of_Neutral_Mono_and_Bis_Phosphonio_i_nido_i_i_ortho_i_Carboranes/2175250
A number
of monosubstituted <i>n</i>-(triphenylphosphonio)-7,8-dicarba-<i>nido</i>-undecaboranes (<b>2a</b>, <i>n</i> =
1; <b>2b</b>, <i>n</i> = 3; <b>2c</b>, <i>n</i> = 5; <b>2d</b>, <i>n</i> = 9) were prepared
via a cross-coupling reaction between the tetrabutylammonium iodo-7,8-dicarba-<i>nido</i>-undecaborates (<b>1a</b>–<b>d</b>) and PPh<sub>3</sub> in the presence of a Pd(PPh<sub>3</sub>)<sub>4</sub> catalyst. The substitution rate was found to depend on the
iodine position in the carborane cage. Under similar conditions, the
reaction of 5,6-diiodo- (<b>3</b>) and 9,11-diiodo-7,8-dicarba-<i>nido</i>-undecaborate (<b>5</b>) anions exclusively yielded
the monosubstitution products 5-iodo-6-(triphenylphosphonio)-7,8-dicarba-<i>nido</i>-undecaborane (<b>4</b>) and 9-iodo-11-(triphenylphosphonio)-7,8-dicarba-<i>nido</i>-undecaborane (<b>6</b>), respectively. The reaction
of tetrabutylammonium 6,9-diiodo-7,8-dicarba-<i>nido</i>-undecaborate (<b>7</b>) exclusively produced the phosphine
substitution product in the open face of the <i>nido</i>-carborane, 6-iodo-9-triphenylphosphonio-7,8-dicarba-<i>nido</i>-undecaborane (<b>8</b>). The addition of a base (Cs<sub>2</sub>CO<sub>3</sub>, NaH) to the reactions of <b>3</b> and <b>5</b> with PPh<sub>3</sub> afforded the corresponding bis(triphenylphosphonio)-7,8-dicarba-<i>nido</i>-undecaboranes, <b>9</b> and <b>10</b>.
Compound <b>10</b> was also prepared from <b>6</b> using
the general procedure. The reaction of the triiodocarborane tetrabutylammonium
5,6,9-triiodo-7,8-dicarba-<i>nido</i>-undecaborate (<b>11</b>) with excess PPh<sub>3</sub> in the presence of Cs<sub>2</sub>CO<sub>3</sub> and Pd(PPh<sub>3</sub>)<sub>4</sub> only produced neutral 5-iodo-6,9-bis(triphenylphosphonio)-7,8-dicarba-<i>nido</i>-undecaborane (<b>12</b>); no positively charged
tris(phosphonio) species formed. The compositions of all prepared
compounds were determined by multinuclear NMR spectroscopy and high-resolution
mass spectrometry. The structures of compounds <b>2c</b>, <b>6</b>, <b>8</b>, <b>9</b>, and <b>12</b> were
established by the X-ray diffraction analysis of single crystals.