3 research outputs found
Toward Permetalated Alkyne/Azide 3 + 2 or “Click” Cycloadducts
No full textThe CuÂ(I)-catalyzed reaction of the platinum butadiynyl
complex <i>trans</i>-(C<sub>6</sub>F<sub>5</sub>)Â(<i>p</i>-tol<sub>3</sub>P)<sub>2</sub>PtÂ(Cî—ĽC)<sub>2</sub>H and rhenium cyclopentadienylazide complex (η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>N<sub>3</sub>)ÂReÂ(CO)<sub>3</sub> yields the 1,2,3-triazole <i>trans</i>-(C<sub>6</sub>F<sub>5</sub>)Â(<i>p</i>-tol<sub>3</sub>P)<sub>2</sub>PtCî—ĽCCî—»CHNÂ((η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>)ÂReÂ(CO)<sub>3</sub>)ÂNî—»N (54%), which upon treatment with ReÂ(CO)<sub>5</sub>OTf
or ReÂ(CO)<sub>5</sub>Br affords ReÂ(CO)<sub>5</sub><sup>+</sup>TfO<sup>–</sup> or <i>cis</i>-ReÂ(CO)<sub>4</sub>Br adducts
derived from attack at N(3) (84–98%). The crystal structures
of solvates of these three complexes are compared, but attempts to
metalate the î—»CH groups were unsuccessful. However, the reaction
of monometallic <i>trans</i>-(C<sub>6</sub>F<sub>5</sub>)Â(<i>p</i>-tol<sub>3</sub>P)<sub>2</sub>PtCî—ĽCCî—»CHNÂ(CH<sub>2</sub>C<sub>6</sub>H<sub>5</sub>)ÂNî—»N and
MeI gives an N(3)-methyl triazolium salt (81%), which upon addition
of Ag<sub>2</sub>O and [RhClÂ(cod)]<sub>2</sub> yields the N-heterocyclic
carbene complex <i>trans</i>-(C<sub>6</sub>F<sub>5</sub>)Â(<i>p</i>-tol<sub>3</sub>P)<sub>2</sub>PtCî—ĽCC<sup><u>...</u></sup>CÂ(RhClÂ(cod))<sup><u>...</u></sup>NÂ(CH<sub>2</sub>C<sub>6</sub>H<sub>5</sub>)<sup><u>...</u></sup>N<sup><u>...</u></sup>NÂ(Me). Further
experiments and analyses suggest that î—»CH derivatization is
possible only when the <sup>1</sup>H NMR chemical shift is downfield
of ca. δ 7.9 ppm. Electropositive metal fragments generally
effect upfield shifts, meaning that insulating spacers, electronegative
ligands, and/or new chemical methodologies will be required to construct
tetrametallic arrays via click chemistry
Gyroscope-Like Platinum and Palladium Complexes with Trans-Spanning Bis(pyridine) Ligands
No full textPyridines with one or two substituents terminating in
vinyl groups
are prepared. Intramolecular ring-closing metatheses of <i>trans</i>-MCl<sub>2</sub> adducts and hydrogenations supply the title compounds.
Williamson ether syntheses using the alcohols HOÂ(CH<sub>2</sub>)<sub><i>n</i></sub>CHî—»CH<sub>2</sub> (<i>n</i> = 1 (<b>a</b>), 2 (<b>b</b>), 3 (<b>c</b>), 4
(<b>d</b>), 5 (<b>e</b>), 6 (<b>f</b>), 8 (<b>h</b>), 9 (<b>i</b>)) and appropriate halides give the pyridines
2-NC<sub>5</sub>H<sub>4</sub>(CH<sub>2</sub>OÂ(CH<sub>2</sub>)<sub><i>n</i></sub>CHî—»CH<sub>2</sub>) (<b>1a</b>,<b>b</b>), 3-NC<sub>5</sub>H<sub>4</sub>(CH<sub>2</sub>OÂ(CH<sub>2</sub>)<sub><i>n</i></sub>CHî—»CH<sub>2</sub>) (<b>2a</b>–<b>e</b>,<b>h</b>,<b>i</b>), and
2,6-NC<sub>5</sub>H<sub>3</sub>(CH<sub>2</sub>OÂ(CH<sub>2</sub>)<sub><i>n</i></sub>CHî—»CH<sub>2</sub>)<sub>2</sub> (<b>4a</b>–<b>d</b>) in 92–45% yields. Reactions
of 3,5-NC<sub>5</sub>H<sub>3</sub>(COCl)<sub>2</sub> and HOÂ(CH<sub>2</sub>)<sub><i>n</i></sub>CHî—»CH<sub>2</sub> afford
the diesters 3,5-NC<sub>5</sub>H<sub>3</sub>(COOÂ(CH<sub>2</sub>)<sub><i>n</i></sub>CHî—»CH<sub>2</sub>)<sub>2</sub> (<b>5a</b>–<b>f</b>,<b>h</b>, 90–41%). The
reaction of 3,5-NC<sub>5</sub>H<sub>3</sub>(4-C<sub>6</sub>H<sub>4</sub>OH)<sub>2</sub>, BrÂ(CH<sub>2</sub>)<sub>5</sub>CHî—»CH<sub>2</sub>, and Cs<sub>2</sub>CO<sub>3</sub> yields 3,5-NC<sub>5</sub>H<sub>3</sub>(4-C<sub>6</sub>H<sub>4</sub>OÂ(CH<sub>2</sub>)<sub>5</sub>CHî—»CH<sub>2</sub>)<sub>2</sub> (<b>8</b>; 32%). Reactions
of PtCl<sub>2</sub> with <b>1a</b>,<b>b</b>, <b>2a</b>–<b>e</b>,<b>h</b>,<b>i</b>, <b>4a</b>,<b>b</b> (but not <b>4c</b>,<b>d</b>), <b>5a</b>,<b>c</b>–<b>f</b>,<b>h</b>, and <b>8</b> afford the corresponding bisÂ(pyridine) complexes <i>trans</i>-<b>10a</b>,<b>b</b> (40–12%), <i>trans</i>-<b>12a</b>–<b>e</b>,<b>h</b>,<b>i</b> (84–46%), <i>trans</i>-<b>17a</b>,<b>b</b> (88–22%), <i>trans</i>-<b>19a</b>,<b>c</b>–<b>f</b>,<b>h</b> (94–63%), and <i>trans</i>-<b>22</b> (96%). Selected adducts are treated
with Grubbs’ catalyst and then H<sub>2</sub> (Pd/C) to give <i>trans</i>-PtCl<sub>2</sub>[2,2′-(NC<sub>5</sub>H<sub>4</sub>(CH<sub>2</sub>OÂ(CH<sub>2</sub>)<sub>2<i>n</i>+2</sub>OCH<sub>2</sub>)ÂH<sub>4</sub>C<sub>5</sub>N)] (<i>trans</i>-<b>11a</b>,<b>b</b>; 79–63%), <i>trans</i>-PtCl<sub>2</sub>[3,3′-(NC<sub>5</sub>H<sub>4</sub>(CH<sub>2</sub>OÂ(CH<sub>2</sub>)<sub>2<i>n</i>+2</sub>OCH<sub>2</sub>)ÂH<sub>4</sub>C<sub>5</sub>N)] (<i>trans</i>-<b>13</b>,<b>d</b>,<b>h</b>,<b>i</b>; 93–80%), <i>trans</i>-PtCl<sub>2</sub>[2,6,2′,6′-(NC<sub>5</sub>H<sub>3</sub>(CH<sub>2</sub>OÂ(CH<sub>2</sub>)<sub>2<i>n</i>+2</sub>OCH<sub>2</sub>)<sub>2</sub>H<sub>3</sub>C<sub>5</sub>N)] (<i>trans</i>-<b>18a</b>,<b>b</b>; 22–10%), <i>trans</i>-PtCl<sub>2</sub>[3,5,3′,5′-(NC<sub>5</sub>H<sub>3</sub>(COOÂ(CH<sub>2</sub>)<sub>2<i>n</i>+2</sub>OCO)<sub>2</sub>H<sub>3</sub>C<sub>5</sub>N)] (<i>trans-</i><b>20d</b>–<b>f</b>,<b>h</b>; 45–14%),
and <i>trans</i>-PtCl<sub>2</sub>[3,5,3′,5′-(NC<sub>5</sub>H<sub>3</sub>(4-C<sub>6</sub>H<sub>4</sub>OÂ(CH<sub>2</sub>)<sub>12</sub>O-4-C<sub>6</sub>H<sub>4</sub>)<sub>2</sub>H<sub>3</sub>C<sub>5</sub>N)] (40%). A previously reported
ring-closing metathesis of <i>trans</i>-PdCl<sub>2</sub>[2,6-NC<sub>5</sub>H<sub>3</sub>(CH<sub>2</sub>CH<sub>2</sub>CHî—»CH<sub>2</sub>)<sub>2</sub>]<sub>2</sub> is confirmed, and the new hydrogenation
product <i>trans</i>-PdCl<sub>2</sub>[2,6,2′,6′-(NC<sub>5</sub>H<sub>3</sub>((CH<sub>2</sub>)<sub>6</sub>)<sub>2</sub>H<sub>3</sub>C<sub>5</sub>N)] (<i>trans-</i><b>16</b>; 62%) is isolated. Additions of CH<sub>3</sub>MgBr
to <b>12b</b>,<b>h</b> and <b>13d</b>,<b>h</b> afford the corresponding PtClCH<sub>3</sub> species (94–41%),
but analogous reactions fail with 2-substituted pyridine adducts.
The reaction of <i>trans</i>-<b>19c</b> with PhCî—ĽCH
and CuI/<i>i</i>-Pr<sub>2</sub>NH gives the corresponding
PtClÂ(Cî—ĽCPh) adduct (18%). The crystal structures of <i>trans</i>-<b>17a</b>, <i>trans</i>-<b>11b</b>, <i>trans</i>-<b>13d</b>, <i>trans</i>-<b>13h</b>·CH<sub>2</sub>Cl<sub>2</sub>, <i>trans</i>-<b>16</b>, <i>trans</i>-<b>18a</b>,<b>b</b>, and <i>trans</i>-<b>20e</b>·2CHCl<sub>3</sub><sub></sub> are determined. Steric effects in the preceding
data, especially involving 2-substituents and the MCl<sub>2</sub> or
MClÂ(X) rotators, are analyzed in detail
