The syntheses of cationic ruthenium(II)
allenylidene complexes
[(1a−e)PF6] of the
type
[CpRu(CCCR2)(PPh3)2]PF6
(1a, R2C: = cycloheptatrienylidene;
1b, R2C: = 2,7-dimethyl-4,5-benzocycloheptatrienylidene; 1c, R2C: =
2,7-diphenyl-4,5-benzocycloheptatrienylidene;
1d, R2C: =
dibenzo[a,e]cycloheptatrienylidene;
1e, R2C: =
4,5-dihydrodibenzo[a,e]cycloheptatrienylidene) are reported. In the series
1a−e, the decreasing ability of
R2C: to stabilize
a positive charge results in a tuning of the electronic and optical
properties by changing the
relative contributions of the two canonical forms
[Ru+]CCCR2 (A) and
[Ru]C⋮CCR2
+
(B), which is studied particularly by NMR and UV/visible
spectroscopy. The first molecular
hyperpolarizabilitiy β of (1b)PF6 has
been determined by hyper Raleigh scattering. The
X-ray crystal structures of (1b)PF6,
(1d)PF6·CH2Cl2,
and the acetylide complex CpRu(C⋮C−C7H7-2,4,6)(PPh3)2
are presented.
Template syntheses of sesquifulvalenes
(2,4,6-cycloheptatrien-1-ylidene)cyclopentadiene
(1) and
[(2,4,6-cycloheptatrien-1-ylidene)ethenylidene]cyclopentadiene
(2) lead to air-stable
complexes
[(1)Mn(CO)2L]BF4
(4) and
[(2)Mn(CO)2L]BF4
(8) (a, L = CO; b, L =
P(OMe)3; c,
L = PPh3). The different σ-donor/π-acceptor
abilities of the ligands L allow a tuning of the
electronic and optical properties of complexes 4 and
8, which are particularly studied by
UV/vis spectroscopy. The first molecular hyperpolarizabilities β
of complexes 4 and 8 have
been determined in dichloromethane and acetonitrile solutions by hyper
Raleigh scattering.
The X-ray crystal structures of 4b, 8b, and
of the alkenylcyclopentadienyl complex [4,5η-(2,4,6-cycloheptatrien-1-yl)-η5-cyclopentadienyl]dicarbonylmanganese(I)
(5) are reported.
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