Structure, reactivity, and electronic properties of [4]ferrocenophanes and [4]ruthenocenophanes prepared via a novel heteroannular cyclization reaction

John K. Pudelski, Matthew R Callstrom

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54 Citations (Scopus)

Abstract

The reactions of 1,1′-bis((trimethylsilyl)ethynyl)ferrocene and 1,1′-bis((trimethylsilyl)ethynyl)ruthenocene with catalytic quantities of alkali-metal methoxides in methanol directly afforded the highly unsaturated [4]metallocenophanes 1,1′-d-methoxy-1,3-butadienylene)-ferrocene and 1,1′-(1-methoxy-1,3-butadienylene)ruthenocene, respectively, in high yields via a novel desilylation/heteroannular cyclization sequence. Analogously, 1,1′-bis((trimethylsilyl)ethynyl)octamethylferrocene reacted to give 1,1′-(1-methoxy-1,3-butadienylene)octamethylferrocene in high yield. The reactions of ((trimethylsilyl)ethynyl)ferrocene and ((trimethylsilyl)ethynyl)ruthenocene under identical conditions afforded ethynylferrocene and ethynylruthenocene, respectively. Synthetic elaboration of the heteroannular bridge of the cyclization products provided a route to additional [4]metallocenophanes. Treatment of 1,1′-(1-methoxy-1,3-butadienylene)ferrocene with acidic silica gel afforded 1,1′-(4-oxo-1-butenylene)ferrocene. Reaction of 1,1′-(4-oxo-1-butenylene)ferrocene with alane provided 1,1′-(1-butenylene)ferrocene, while reaction with sodium borohydride gave 1,1′-(4-hydroxy-1-butenylene)ferrocene. Dehydration of 1,1′-(4-hydroxy-1-butenylene)ferrocene on activated alumina provided 1,1′-(1,3-butadienylene)ferrocene. Similar synthetic transformations were carried out to yield the analogous series of ruthenocenophanes and octamethylferrocenophanes. Voltammetric half-wave oxidation potentials were measured for all of the metallocenophanes in order to evaluate the electronic effect of the heteroannular bridges. X-ray crystal structure analyses were carried out on 1-1′-(1-methoxy-1,3-butadienylene)ferrocene and 1,1′-(1-methoxy-1,3-butadienylene)ruthenocene. 1,1′-(1-Methoxy-1,3-butadienylene)ferrocene, C 15H 14FeO, crystallized in the orthorhombic space group Pcnb with a = 26.997(5) Å, b = 5.981(2) Å, c = 28.962(3) Å, Z = 16, and R = 0.072. 1,1′-(1-Methoxy-1,3-butadienylene)ruthenocene, C 15H 14RuO, crystallized in the monoclinic C2/c space group with a = 20.590(3) Å, b = 9.023(2) Å, c = 13.940(2) Å, β= 111.296(8)°, Z = 8, and R = 0.021.

Original languageEnglish (US)
Pages (from-to)3095-3109
Number of pages15
JournalOrganometallics
Volume13
Issue number8
StatePublished - 1994
Externally publishedYes

Fingerprint

Cyclization
Electronic properties
reactivity
electronics
borohydrides
silica gel
dehydration
alkali metals
methyl alcohol
aluminum oxides
routes
sodium
oxidation
crystal structure
ferrocene
products
Activated alumina
Alkali Metals
x rays
Silica Gel

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Organic Chemistry

Cite this

@article{60aa5030c3c2483fb78333e64f04674e,
title = "Structure, reactivity, and electronic properties of [4]ferrocenophanes and [4]ruthenocenophanes prepared via a novel heteroannular cyclization reaction",
abstract = "The reactions of 1,1′-bis((trimethylsilyl)ethynyl)ferrocene and 1,1′-bis((trimethylsilyl)ethynyl)ruthenocene with catalytic quantities of alkali-metal methoxides in methanol directly afforded the highly unsaturated [4]metallocenophanes 1,1′-d-methoxy-1,3-butadienylene)-ferrocene and 1,1′-(1-methoxy-1,3-butadienylene)ruthenocene, respectively, in high yields via a novel desilylation/heteroannular cyclization sequence. Analogously, 1,1′-bis((trimethylsilyl)ethynyl)octamethylferrocene reacted to give 1,1′-(1-methoxy-1,3-butadienylene)octamethylferrocene in high yield. The reactions of ((trimethylsilyl)ethynyl)ferrocene and ((trimethylsilyl)ethynyl)ruthenocene under identical conditions afforded ethynylferrocene and ethynylruthenocene, respectively. Synthetic elaboration of the heteroannular bridge of the cyclization products provided a route to additional [4]metallocenophanes. Treatment of 1,1′-(1-methoxy-1,3-butadienylene)ferrocene with acidic silica gel afforded 1,1′-(4-oxo-1-butenylene)ferrocene. Reaction of 1,1′-(4-oxo-1-butenylene)ferrocene with alane provided 1,1′-(1-butenylene)ferrocene, while reaction with sodium borohydride gave 1,1′-(4-hydroxy-1-butenylene)ferrocene. Dehydration of 1,1′-(4-hydroxy-1-butenylene)ferrocene on activated alumina provided 1,1′-(1,3-butadienylene)ferrocene. Similar synthetic transformations were carried out to yield the analogous series of ruthenocenophanes and octamethylferrocenophanes. Voltammetric half-wave oxidation potentials were measured for all of the metallocenophanes in order to evaluate the electronic effect of the heteroannular bridges. X-ray crystal structure analyses were carried out on 1-1′-(1-methoxy-1,3-butadienylene)ferrocene and 1,1′-(1-methoxy-1,3-butadienylene)ruthenocene. 1,1′-(1-Methoxy-1,3-butadienylene)ferrocene, C 15H 14FeO, crystallized in the orthorhombic space group Pcnb with a = 26.997(5) {\AA}, b = 5.981(2) {\AA}, c = 28.962(3) {\AA}, Z = 16, and R = 0.072. 1,1′-(1-Methoxy-1,3-butadienylene)ruthenocene, C 15H 14RuO, crystallized in the monoclinic C2/c space group with a = 20.590(3) {\AA}, b = 9.023(2) {\AA}, c = 13.940(2) {\AA}, β= 111.296(8)°, Z = 8, and R = 0.021.",
author = "Pudelski, {John K.} and Callstrom, {Matthew R}",
year = "1994",
language = "English (US)",
volume = "13",
pages = "3095--3109",
journal = "Organometallics",
issn = "0276-7333",
publisher = "American Chemical Society",
number = "8",

}

TY - JOUR

T1 - Structure, reactivity, and electronic properties of [4]ferrocenophanes and [4]ruthenocenophanes prepared via a novel heteroannular cyclization reaction

AU - Pudelski, John K.

AU - Callstrom, Matthew R

PY - 1994

Y1 - 1994

N2 - The reactions of 1,1′-bis((trimethylsilyl)ethynyl)ferrocene and 1,1′-bis((trimethylsilyl)ethynyl)ruthenocene with catalytic quantities of alkali-metal methoxides in methanol directly afforded the highly unsaturated [4]metallocenophanes 1,1′-d-methoxy-1,3-butadienylene)-ferrocene and 1,1′-(1-methoxy-1,3-butadienylene)ruthenocene, respectively, in high yields via a novel desilylation/heteroannular cyclization sequence. Analogously, 1,1′-bis((trimethylsilyl)ethynyl)octamethylferrocene reacted to give 1,1′-(1-methoxy-1,3-butadienylene)octamethylferrocene in high yield. The reactions of ((trimethylsilyl)ethynyl)ferrocene and ((trimethylsilyl)ethynyl)ruthenocene under identical conditions afforded ethynylferrocene and ethynylruthenocene, respectively. Synthetic elaboration of the heteroannular bridge of the cyclization products provided a route to additional [4]metallocenophanes. Treatment of 1,1′-(1-methoxy-1,3-butadienylene)ferrocene with acidic silica gel afforded 1,1′-(4-oxo-1-butenylene)ferrocene. Reaction of 1,1′-(4-oxo-1-butenylene)ferrocene with alane provided 1,1′-(1-butenylene)ferrocene, while reaction with sodium borohydride gave 1,1′-(4-hydroxy-1-butenylene)ferrocene. Dehydration of 1,1′-(4-hydroxy-1-butenylene)ferrocene on activated alumina provided 1,1′-(1,3-butadienylene)ferrocene. Similar synthetic transformations were carried out to yield the analogous series of ruthenocenophanes and octamethylferrocenophanes. Voltammetric half-wave oxidation potentials were measured for all of the metallocenophanes in order to evaluate the electronic effect of the heteroannular bridges. X-ray crystal structure analyses were carried out on 1-1′-(1-methoxy-1,3-butadienylene)ferrocene and 1,1′-(1-methoxy-1,3-butadienylene)ruthenocene. 1,1′-(1-Methoxy-1,3-butadienylene)ferrocene, C 15H 14FeO, crystallized in the orthorhombic space group Pcnb with a = 26.997(5) Å, b = 5.981(2) Å, c = 28.962(3) Å, Z = 16, and R = 0.072. 1,1′-(1-Methoxy-1,3-butadienylene)ruthenocene, C 15H 14RuO, crystallized in the monoclinic C2/c space group with a = 20.590(3) Å, b = 9.023(2) Å, c = 13.940(2) Å, β= 111.296(8)°, Z = 8, and R = 0.021.

AB - The reactions of 1,1′-bis((trimethylsilyl)ethynyl)ferrocene and 1,1′-bis((trimethylsilyl)ethynyl)ruthenocene with catalytic quantities of alkali-metal methoxides in methanol directly afforded the highly unsaturated [4]metallocenophanes 1,1′-d-methoxy-1,3-butadienylene)-ferrocene and 1,1′-(1-methoxy-1,3-butadienylene)ruthenocene, respectively, in high yields via a novel desilylation/heteroannular cyclization sequence. Analogously, 1,1′-bis((trimethylsilyl)ethynyl)octamethylferrocene reacted to give 1,1′-(1-methoxy-1,3-butadienylene)octamethylferrocene in high yield. The reactions of ((trimethylsilyl)ethynyl)ferrocene and ((trimethylsilyl)ethynyl)ruthenocene under identical conditions afforded ethynylferrocene and ethynylruthenocene, respectively. Synthetic elaboration of the heteroannular bridge of the cyclization products provided a route to additional [4]metallocenophanes. Treatment of 1,1′-(1-methoxy-1,3-butadienylene)ferrocene with acidic silica gel afforded 1,1′-(4-oxo-1-butenylene)ferrocene. Reaction of 1,1′-(4-oxo-1-butenylene)ferrocene with alane provided 1,1′-(1-butenylene)ferrocene, while reaction with sodium borohydride gave 1,1′-(4-hydroxy-1-butenylene)ferrocene. Dehydration of 1,1′-(4-hydroxy-1-butenylene)ferrocene on activated alumina provided 1,1′-(1,3-butadienylene)ferrocene. Similar synthetic transformations were carried out to yield the analogous series of ruthenocenophanes and octamethylferrocenophanes. Voltammetric half-wave oxidation potentials were measured for all of the metallocenophanes in order to evaluate the electronic effect of the heteroannular bridges. X-ray crystal structure analyses were carried out on 1-1′-(1-methoxy-1,3-butadienylene)ferrocene and 1,1′-(1-methoxy-1,3-butadienylene)ruthenocene. 1,1′-(1-Methoxy-1,3-butadienylene)ferrocene, C 15H 14FeO, crystallized in the orthorhombic space group Pcnb with a = 26.997(5) Å, b = 5.981(2) Å, c = 28.962(3) Å, Z = 16, and R = 0.072. 1,1′-(1-Methoxy-1,3-butadienylene)ruthenocene, C 15H 14RuO, crystallized in the monoclinic C2/c space group with a = 20.590(3) Å, b = 9.023(2) Å, c = 13.940(2) Å, β= 111.296(8)°, Z = 8, and R = 0.021.

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