Abstract:The reactions of trans-[PtH(PEt3)2(acetone)]+ and trans-[PtH(PEt3)2(CO)]+ with a variety of acetylenes are described. The geometries of the products with respect to the platinum centre and to the stereochemistry of the alkenyl group have been determined on the basis of their 1H nmr parameters. For reactions with the cation containing acetone, and particularly from a variable temperature 1H nmr study of its reaction with 2-butyne in the presence of water, the insertion pathway is shown to be entirely analogous … Show more
“…However, theoretical calculations indicate that the low energy pathway for alkyne insertions in platinum(II) systems proceeds from four-coordinate square-planar complexes . There is much experimental evidence to substantiate this prediction. ,,, In addition, as mentioned above, we have not obtained any evidence for the associative attack of diphenylacetylene on 1 or any 4-coordinate intermediate in this system. Thus, we disfavor an associative mechanism for the conversion of 12 to 8 .…”
Section: Discussionmentioning
confidence: 57%
“…Each Pt is essentially square-planar coordinate in which the two σ-bound carbons are oriented cis to one another and each is trans to a coordinated π-bond. The stereochemistry about the terminal double bond of the tetraphenylbutadienyl ligand is trans. − 4 ORTEP drawing of one of the two independent molecules in the asymmetric unit of 8 .…”
The synthesis, characterization, chemical vapor deposition, and
mechanistic investigation of the thermal
decomposition in aromatic solvents of
cis-bis(η2,η1-pent-4-en-1-yl)platinum
(1) are described. Complex 1 has
a
unique chelated structure, giving rise to enhanced volatility, and has
proved useful for the chemical vapor deposition
of thin platinum films under mild conditions. Films deposited on a
glass slide in a hot walled glass tube at 175 °C
have an elemental composition of 82% Pt and 18% C. Kinetic,
deuterium labeling, and chemical trapping experiments
indicate that the decomposition of 1 in aromatic solvents
proceeds by reversible β-hydride elimination followed by
reversible dissociation of 1,4-pentadiene to give a 3-coordinate
platinum hydride intermediate (9).
Reductive
elimination of 1-pentene from 9 deposits metallic platinum.
The rate of decomposition exhibits a significant
β-deuterium isotope effect of
k
H/k
D = 3.8 ± 0.3.
Added olefins are rapidly isomerized during the decomposition
of
1; trapping experiments with diphenylacetylene indicate that
intermediate 9 is the highly active catalyst that
is
responsible for the alkene isomerization.
“…However, theoretical calculations indicate that the low energy pathway for alkyne insertions in platinum(II) systems proceeds from four-coordinate square-planar complexes . There is much experimental evidence to substantiate this prediction. ,,, In addition, as mentioned above, we have not obtained any evidence for the associative attack of diphenylacetylene on 1 or any 4-coordinate intermediate in this system. Thus, we disfavor an associative mechanism for the conversion of 12 to 8 .…”
Section: Discussionmentioning
confidence: 57%
“…Each Pt is essentially square-planar coordinate in which the two σ-bound carbons are oriented cis to one another and each is trans to a coordinated π-bond. The stereochemistry about the terminal double bond of the tetraphenylbutadienyl ligand is trans. − 4 ORTEP drawing of one of the two independent molecules in the asymmetric unit of 8 .…”
The synthesis, characterization, chemical vapor deposition, and
mechanistic investigation of the thermal
decomposition in aromatic solvents of
cis-bis(η2,η1-pent-4-en-1-yl)platinum
(1) are described. Complex 1 has
a
unique chelated structure, giving rise to enhanced volatility, and has
proved useful for the chemical vapor deposition
of thin platinum films under mild conditions. Films deposited on a
glass slide in a hot walled glass tube at 175 °C
have an elemental composition of 82% Pt and 18% C. Kinetic,
deuterium labeling, and chemical trapping experiments
indicate that the decomposition of 1 in aromatic solvents
proceeds by reversible β-hydride elimination followed by
reversible dissociation of 1,4-pentadiene to give a 3-coordinate
platinum hydride intermediate (9).
Reductive
elimination of 1-pentene from 9 deposits metallic platinum.
The rate of decomposition exhibits a significant
β-deuterium isotope effect of
k
H/k
D = 3.8 ± 0.3.
Added olefins are rapidly isomerized during the decomposition
of
1; trapping experiments with diphenylacetylene indicate that
intermediate 9 is the highly active catalyst that
is
responsible for the alkene isomerization.
“…The starting material frares-L2PtHCl was prepared by Parshall's method;18 and the following metal acetylides [14][15][16][17][18][19][20][21][22] were prepared by literature methods: trons-L2Pt(C=CR)2 (14 and 15 (R = H or Me));19 (j7-C6H5)(OC)2Fe(C=CPh) (16);20 LAu(C=CPh) (17 and 18 (L = PEt, or PPhg));21•22 (s-C6H5)(OC)3W(C^CPh) (19);23 tr<ms-L2Ni(C=CPh)2 (20);24 and trons-L2Pd(C=CPh)2 (21). 26 Preparation of [ 2(µ-0=€ ß)(0^3 ß)( 3)4] 6 (5).…”
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