Facile Access to Mono- and Dinuclear Heteroleptic N‑Heterocyclic Silylene Copper Complexes
dataset
posted on 2014-01-13, 00:00 authored by Gengwen Tan, Burgert Blom, Daniel Gallego, Matthias DriessReaction of the heteroleptic N-heterocyclic
chlorosilylene L(Cl)Si:
(1; L = PhC(NtBu)2) with
[Cu(tmeda)(CH3CN)][OTf] (2; tmeda = N,N,N′,N′-tetramethylethylenediamine,
OTf = OSO2CF3 (triflate)) affords the Cu(I)
complex [L(Cl)Si:→Cu(tmeda)][OTf] (3) in high
yield as the first example of a heteroleptic N-heterocyclic silylene
copper complex. Similarly, the reaction of L(OtBu)Si:
(4; L = PhC(NtBu)2) with 2 affords [L(OtBu)Si: → Cu(tmeda)][OTf]
(5) and that of L(NMe2)Si: (6) with 2 leads to [L(NMe2)Si:→Cu(tmeda)][OTf]
(7). Complex 3 shows a rather strong interaction
in the solid state between the O atom of the triflate anion and the
three-coordinate Cu(I) center with a Cu···O distance
of 2.312 Å. In contrast, complex 7 features only
a weak interaction (ca. 3.28 Å), while in complex 5 the cation and anion are fully separated. Strikingly, the reaction
of the chelating oxo-bridged silylene :Si(L)(μ2-O)(L)Si:
(8) with the copper source [Cu(CH3CN)4][OTf] (9) affords the dinuclear complex salt
[Cu2{η1:η1-LSi(μ2-O)SiL}2][OTf]2 (10), featuring
a novel metallacyclooctane dication, selectively in a good yield.
Complex 10 also exhibits a very strong interaction between
the copper centers in the dication and the oxygen atoms of triflate
anions in the solid state, evidenced by a Cu···O separation
of only 2.141 Å. All complexes were fully characterized.
