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Synthesis, Structure, and Reactivity of sp Carbon Chains with Bis(phosphine) Pentafluorophenylplatinum Endgroups: Butadiynediyl (C 4 ) through Hexadecaoctaynediyl (C 16 ) Bridges, and Beyond
Author(s) -
Mohr Wolfgang,
Stahl Jürgen,
Hampel Frank,
Gladysz J. A.
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200204741
Subject(s) - chemistry , yield (engineering) , triple bond , phosphine , acetone , medicinal chemistry , single bond , stereochemistry , double bond , polymer chemistry , materials science , organic chemistry , catalysis , metallurgy , alkyl
The reaction of trans ‐[(C 6 F 5 )( p ‐tol 3 P) 2 PtCl] ( PtCl ) and butadiyne (cat. CuI, HNEt 2 ) gives trans ‐[(C 6 F 5 )( p ‐tol 3 P) 2 Pt(CC) 2 H] ( PtC 4 H , 81 %), which reacts with excess HCCSiEt 3 under Hay coupling conditions (O 2 , cat. CuCl/TMEDA, acetone) to yield PtC 6 Si (53 %). A solution of PtC 6 Si in acetone is treated with wet n Bu 4 NF to generate PtC 6 H . The addition of ClSiMe 3 (F − scavenger) and then excess HCCSiEt 3 under Hay conditions gives PtC 8 Si (39 %). Hay homocouplings of PtC 4 H, PtC 6 H , and PtC 8 H (generated in situ analogously to PtC 6 H ) yield PtC 8 Pt, PtC 12 Pt , and PtC 16 Pt (97–92 %). Reactions of PtC 4 H and PtC 6 H with PtCl (cat. CuCl, HNEt 2 ) give PtC 4 Pt and PtC 6 Pt (69 %, 34 %). The attempted conversion of PtC 8 H to PtC 10 Si affords mainly PtC 16 Pt , with traces of PtC 20 Pt and PtC 24 Pt . The complexes PtC x Pt are exceedingly stable (dec pts 234 to 288 °C), and Et 3 P displaces p ‐tol 3 P to give the corresponding compounds Pt′C 8 Pt′ and Pt′C 12 Pt′ (94–90 %). The effect of carbon chain lengths upon IR ν CC patterns (progressively more bands), UV/Vis spectra (progressively red‐shifted and more intense bands with ε >600 000 M −1 cm −1 ), redox properties (progressively more difficult and less reversible oxidations), and NMR values are studied, and analyzed with respect to the polymeric sp carbon allotrope “carbyne”. The crystal structure of PtC 12 Pt shows a dramatic, unprecedented degree of chain bending, whereas the chains in PtC 8 Pt, Pt′C 12 Pt′ , and PtC 16 Pt are nearly linear.