F. Bigoli et al., Synthesis, structure and properties of new unsymmetrical nickel dithiolenecomplexes useful as near-infrared dyes, J CHEM S DA, (24), 2000, pp. 4639-4644
Citations number
20
Categorie Soggetti
Inorganic & Nuclear Chemistry
Journal title
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
The new unsymmetrical [Bu4N][Ni(Pr(2)(i)timdt)(dmit)] 4 and [Bu4N][Ni(Pr(2)
(i)timdt)(mnt)] 5 dithiolene complexes (Pr(2)(i)timdt is the mono-anion of
1,3-diisopropylimidazolidine-2,4,5-trithione; dmit=2-thioxo-1,3-dithiole-4,
5-dithiolate; mnt=maleonitriledithiolate) have been prepared from the react
ion of the neutral complex [Ni(Pr(2)(i)timdt)(2)] 1 with the bi-anionic nic
kel dithiolene complexes [Bu4N](2)[Ni(dmit)(2)] 2 or [Bu4N](2)[Ni(mnt)(2)]
3, respectively. A strong near-IR electronic absorption is observed in the
spectra of 4 and 5 in CH3CN at lambda (max)=1194 and 1070 nm, respectively.
Diiodine oxidation of 4 and 5 affords the [Ni(Pr(2)(i)timdt)(dmit)] 6 and
[Ni(Pr(2)(i)timdt)(mnt)] 7 neutral compounds (lambda (max) at 883 nm in CH3
CN). Features in the electronic spectra suggest that the properties of unsy
mmetrical nickel dithiolene complexes as near-infrared dyes can be tuned by
a combination of the ligands and by the charge on the complexes. A crystal
of 6 has been analysed by X-ray diffraction methods. Structural data show
that the nickel ion exhibits square-planar co-ordination. Chains along b ar
e formed through contacts between the terminal sulfur atoms of the Pr(2)(i)
timdt and dmit ligands [S . . .S 3.243(2) Angstrom]. The formal charge of t
he ligands in 4 and 6 is estimated from the frequency of the Raman C=C stre
tching vibration.