Charge-separated and molecular heterobimetallic rare earth-rare earth and alkaline earth-rare earth aryloxo complexes featuring intramolecular metal-π-arene interactions

Article abstract of DOI:10.1002/chem.200900229

Treatment of a rare earth metal (Ln) and a potential divalent rare earth metal (Ln′) or an alkaline earth metal (Ae) with 2,6-diphenylphenol (HOdpp) at elevated temperatures (200-250 °C) afforded heterobimetallic aryloxo complexes, which were structurally

Full text of DOI:10.1002/chem.200900229

FULL PAPER
DOI: 10.1002/chem.200900229
Charge-Separated and Molecular Heterobimetallic Rare Earth–Rare Earth
and Alkaline Earth–Rare Earth Aryloxo Complexes Featuring
Intramolecular Metal–p-arene Interactions
Glen B. Deacon,*[a] Peter C. Junk,*[a] Graeme J. Moxey,[a] Karin Ruhlandt-Senge,*[b]
Courtney St. Prix,[b] and Maria F. Zuniga[b]
Abstract: Treatment of a rare earth
metal (Ln) and a potential divalent
rare earth metal (Ln’) or an alkaline
earth metal (Ae) with 2,6-diphenylphe-
nol (HOdpp) at elevated temperatures
(200–2508C) afforded heterobimetallic
aryloxo complexes, which were struc-
turally characterised. A charge-separat-
tained by treating an alkaline earth
metal and Eu metal with HOdpp at
elevated temperatures. Similarly, [BaSr-
donor ligands, the crystal structures of
the heterobimetallic complexes feature
extensive p-Ph–metal interactions in-
volving the pendant phenyl groups of
the Odpp ligands, thus enabling the
large electropositive metal atoms to
attain coordination saturation. The
charge-separated heterobimetallic spe-
cies were purified by extraction with
toluene/thf mixtures at ambient tem-
perature (Ba-containing compounds)
or by extraction with toluene under
pressure above the boiling point of the
solvent (other products). In donor sol-
AHCTUNGTRENNUNG
CTHUNGTRENNUNG
A
CHTUNGTRENNUNG
C
R
CHTUNGTRENNUNG
ed species [(Ln’/Ae)
2ACHTUNGTRENN(UNG Odpp)3][Ln-
G
CHTUNGTRENNUNG
metals, demonstrating the similarities
between the chemistry of the divalent
rare earth metals and the alkaline
ACHTUNGTRENNUNG
free-metal route was essential. As a
result of the absence of additional
earth metals. The [(Ln’/Ae)2ACTHNUTRGNEUNG
(Odpp)3]+
cation in the heterobimetallic struc-
tures is unusual in that it consists solely
of bridging aryloxide ligands. A molec-
ular heterobimetallic species [AeEu-
vents,
heterobimetallic
complexes
Keywords: alkaline earth metals ·
other than those containing barium
were found to fragment into homo-
AHCTUNGTREGmNNNU etallic species.
heterobimetallic
complexes
·
O ligands · pi interactions · rare
earths
ACHTUNGTRENNUNG(Odpp)4] (Ae=Ca, Sr, Ba) was ob-
Introduction
Mixed-oxidation-state (II/III) rare earth metal–organic com-
pounds are quite rare, though they continue to increase in
[a] Prof. Dr. G. B. Deacon, Prof. Dr. P. C. Junk, G. J. Moxey
School of Chemistry
number.[1–11]
Amongst
this
class,
[Yb2 ACTHGNUTERNNUG
II(Odpp)3]+
Monash University
Clayton, VIC 3800 (Australia)
Fax : (+61)399054597
E-mail: glen.deacon@sci.monash.edu.au
peter.junk@sci.monash.edu.au
N
ACTUHNGTRENNCNUGHUTNTRENUNG
prepared by direct reaction of Yb metal with the phenol, is
unusual because of its charge-separated nature and because
the cation contains solely bridging aryloxide ligands.[11] This
structural feature has otherwise been seen only in the mo-
[b] Prof. Dr. K. Ruhlandt-Senge, Dr. C. St. Prix, Dr. M. F. Zuniga
Department of Chemistry
lecular bimetallic complexes [LiSn
(Odpp)3] (M=Li!Rb)[13] and the recently prepared [MAe-
AHCTUNGTRENNUNG
(Odpp)3] (M=Na, K, Cs; Ae=Ca, Sr, Ba).[14,15] An intrigu-
(Odpp)3],[12] [MGe-
ACHTUNGTRENNUNG
1-014 Center for Science and Technology
Syracuse University
Syracuse, NY 13244-4100 (USA)
Fax : (+1)315-443-4070
AHCTUNGTRENNUNG
ing possibility is that 1 could be the forerunner of a new
class of mixed-oxidation-state heterobimetallic complexes,
E-mail: kruhland@syr.edu
II(Odpp)3][LnIII
namely, [Ln’2 ACHTUNTGREUNNNG AHCTUNRGTNENUG ACHTNUGTNER(NGUN Odpp)4] (Ln’=Eu, Sm, Yb;
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.200900229.
Ln=any rare earth element). Furthermore, from the similar-
Chem. Eur. J. 2009, 15, 5503 – 5519
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
5503

ity of the Ca2+/Yb2+ and Sr2+/Eu2+ ionic radii,[16] the mixed
oxidation class might be extended to [Ae2A(Odpp)3][Ln-
(Odpp)4] (Ae=Ca, Sr, Ba) complexes. Moreover, the simi-
larities between the structures of [Yb2A
(Odpp)4][11] and [Ca2-
2A
(Odpp)4][17] and between the structures of [Eu (Odpp)4][11]
and [Ae2A
(Odpp)4] (Ae=Sr, Ba)[17] suggest that a new class
of neutral divalent heterobimetallic species [AeLn(Odpp)4]
charge-separated heterobimetallic 2,6-diphenylphenolate
complexes [(Ln’/Ae)2ACTHUNGRTEN(NUG Odpp)3][LnACTHUNGTREN(NUNG Odpp)4] (Equation (1);
Table 1).
G
E
CTHUNGTRENNUNG
R
CHTUNGTRENNUNG
Table 1. List of heterobimetallic compounds and reaction/work-up condi-
tions employed.
CHTUNGTRENNUNG
AHCTUNGTRENNUNG
Compound
[Yb2A(Odpp)3][Yb
[Yb2A(Odpp)3][Y(Odpp)4]·2PhMe
[Yb2A(Odpp)3][Y
[Yb2A(Odpp)3][Y
[Eu2A(Odpp)3][Y(Odpp)4]
[Eu2A(Odpp)3][Y
[Eu2A(Odpp)3][Nd
[Eu2A(Odpp)3][Ho
[Ca2A(Odpp)3][Nd(Odpp)4]·PhMe
[Ca2A(Odpp)3][Ho(Odpp)4]
[Ca2A(Odpp)3][Tm(Odpp)4]
[Ca2A(Odpp)3][Yb(Odpp)4]
[Sr2A(Odpp)3][Nd
[Sr2A(Odpp)3][Ho
[Ba2A(Odpp)3][Sm
[Ba2A(Odpp)3][Sm
[Ba2A(Odpp)3][Sm
[Ba2A(Odpp)3][Yb(Odpp)4]
[Ba2A(Odpp)3][Mg(Odpp)3A(thf)]
[CaEu(Odpp)4]·PhMe
[SrEu(Odpp)4]
[SrEu(Odpp)4]·PhMe
[BaSr(Odpp)4]
[BaEu(Odpp)4]
[BaEu(Odpp)4]·PhMe
Number
Conditions[a] Flux[b]
might also be accessible. We now report the preparation and
structural characterisation of a new class of mixed-oxida-
G
G
G
1a, 1b
2·2PhMe
A
E
R
G
C
E
tion-state heterobimetallic compounds [(Ln’/Ae)
[Ln(Odpp)4], and the molecular heterobimetallic species
[AeEu(Odpp)4] (Ae=Ca, Sr, Ba) by the simple reaction of
2ACHTUNGTNER(NUNG Odpp)3]
E
R
B
E
N
A
B
E
ACHTUNGTRENNUNG
N
G
U
3
A
F
ACHTUNGTRENNUNG
R
E
(Odpp)4]·0.5PhMe 3·0.5PhMe
B
F
an appropriate mixture of metallic elements with 2,6-diphe-
nylphenol (HOdpp) at elevated temperatures. The wide
range of products obtained establishes the general signifi-
cance and value of the synthetic method, which is potential-
ly applicable to further combinations of Ln and Ae elements
with the present ligand, to analogous bimetallics with other
phenolate and plausibly organoamide ligands, and indeed to
different combinations of elements, such as Ae/Ae’, as
N
E
R
4
5
A
F
T
N
G
A
F
E
E
N
6·PhMe
C, B
A, B
A
A
B
E, F[c]
N
E
E
7
8
9
E, F[d]
E
G
F
N
N
R
R
E
E
G
N
E
U
B
F
R
N
E
12
B
F
E
E
R
12·PhMe
12·4PhMe
13
14
15·PhMe
16
16·PhMe
17
18
D
F
shown by the preparation of [BaSrACTHNUTRGENUG(N Odpp)4].
G
G
A
D
F
A major problem posed by 1 that is also applicable to
many of the present charge-separated complexes is insolu-
bility in non-polar solvents and dissociation into homometal-
lic species in polar solvents, evidently requiring hand-picking
to separate the target bimetallics from residual metal. How-
ever, a major advance has been the purification of represen-
tative compounds by crystallisation from toluene under
pressure well above the boiling point of the solvent to avoid
E
N
A, D
C
C
F
E
F
E
C
E
G
T
R
A
F
E
E
C
F
R
R
A, D
D
F
F
G
R
A
A
18·PhMe
D
F
[a] A=crystals obtained directly from tube; B=crystals obtained by
high-pressure toluene recrystallisation; C=crystals obtained from tolu-
ene at ambient temperature or at ꢀ208C after prolonged storage; D=
crystals obtained from toluene/thf. [b] E=no flux; F=1,3,5-tri-tert-butyl-
benzene; G=1,2,4,5-tetramethylbenzene. [c] Fluxes E and F were used
with conditions C and B, respectively. [d] Fluxes E and F were used with
conditions A and B, respectively.
fragmentation by polar solvents. In addition, [Ba2ACTHNUTRGNEUNG
(Odpp)3]+-
containing complexes can uniquely be crystallised from tolu-
ene/thf without decomposition into the homometallic spe-
cies.
Rare earth and heavier alkaline earth aryloxides and alk-
oxides are of considerable contemporary interest and have
led to a number of reviews and perspective articles,[18,19]
with particular interest in their structural chemistry[19] and
uses in metal–organic chemical vapour deposition, atomic
layer deposition and sol-gel applications,[20] and they make a
significant contribution to a key monograph.[21] The present
complexes add two new exciting structural classes that can
be potentially generalised to other aryloxide and organoa-
mide systems. A feature of the structures of the present
complexes is extensive intramolecular p-Ph–Ln’/Ae bond-
ing. The p bonding of neutral ligands to lanthanoids is well
known in zero-, di- and trivalent arene–lanthanoid complex-
es[22a,b] and inter- and intramolecular p bonding of aryl
groups to Ln (and Ae) elements is an increasing phenomen-
on.[22a,c,d]
Hg, flux
2 ðLn0=AeÞþLnþ7 HOdpp
ƒƒƒƒƒƒƒ!
10ꢀ3 mmHg, D
½ðLn0=AeÞ2ðOdppÞ3ꢁ½LnðOdppÞ4ꢁþ3:5 H2
ð1Þ
Ln0 ¼ Yb, Eu; Ae ¼ Ca, Sr, Ba
Ln ¼ Nd, Sm, Ho, Tm, Yb, Y
Contrastingly, heterobimetallic alkaline earth complex
[Ba
(Odpp)3][Mg
U
(thf)] 14 was prepared by treating
2A(thf)2] in toluene [Eq. (2)], a
2A(Odpp)3][Ln-
(Odpp)4] complexes. Treatment of Eu metal and an alkaline
earth metal with HOdpp afforded a dinuclear molecular
heterobimetallic species [AeEu(Odpp)4] [Eq. (3)] (Ae=Ca
15; Sr 16; Ba 18). Similarly, treatment of Sr metal and Ba
metal with HOdpp afforded [BaSr(Odpp)4] 17 [Eq. (3)].
[Ba
N
N
CHTUNGTRENNUNG
synthesis that did not succeed for [(Ln’/Ae) HCTUNGTRENNUNG
AHCTUNGTRENNUNG
AHCTUNGTRENNUNG
AHCTUNGTRENNUNG
Table 1 contains a summary of the complexes synthesised
and the reaction conditions and work-up methods
Results and Discussion
AHCTUNGTRENNUNG
Syntheses: Treatment of two rare earth metals, of which one
is Yb or Eu, or a combination of a rare earth metal and a
heavy alkaline earth metal (Ca, Sr, Ba) with HOdpp at 200–
2508C in an evacuated and sealed Carius tube afforded
PhMe
ƒƒ!
2
4
2
2
80 ꢂ
C
ð2Þ
½Ba2ðOdppÞ3ꢁ½MgðOdppÞ3ðthfÞꢁ
5504
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Chem. Eur. J. 2009, 15, 5503 – 5519

Rare Earth–Rare Earth and Alkaline Earth–Rare Earth Complexes
FULL PAPER
Hg, flux
MþAeþ4 HOdpp
½AeMðOdppÞ ꢁþ2 H
ð3Þ
ƒƒƒƒƒƒƒ!
4
2
10ꢀ3 mmHg, D
of 2, most syntheses of [(Ln’/Ae)2ACHTNUTRGENN(UG Odpp)3][LnAHCUTGNTREN(NGUN Odpp)4] com-
plexes utilised a considerable excess of Ln. A smaller excess
was employed in reactions involving Ba, which were also
carried out under somewhat more aggressive conditions
(temperature/time). Nevertheless, Ca/Nd and Ca/Ho com-
plexes 6 and 7, having initially been prepared with Ca/Ln
ratios of 1:4 and no flux, were subsequently prepared from
near stoichiometric amounts of the two metals in a 1,3,5-tri-
M=Eu, Ac=Ca/Sr/Ba; M=Sr, Ac=Ba.
Direct metalation is a conceptually simple synthetic route
to homoleptic heterobimetallic species. An added benefit is
that no air-sensitive reagents need to be prepared. The
simple structural frameworks and homoleptic nature of het-
erobimetallic complexes 1–18 contrast with previously re-
ported solvated aryloxo rare earth–alkaline earth heterobi-
tert-butylbenzene flux. Although [Ca2ACHTNUGTRENN(UG Odpp)3][TmACHTUNGTRENNUNG(Odpp)4]
metallic complexes, such as [H2Ba2Sr
(OPh)14]
(hmpa=hexamethylphosphoramide),[23a]
[H2Eu2Ba (OiPr)16A 6A(dig)2-
(thf)4][23b] and [EuBa2Sr
(dme)
G
E
8 was characterised as a hand-picked single crystal, the syn-
thesis could not be repeated. Use of a large excess of Ln led
G
N
G
E
in some cases to formation of [Ln
Sm 21; Ho, Tm 20) accompanying the [(Ln’/Ae)
[Ln(Odpp)4] bimetallic complex, but was easily removed
owing to its high solubility in cold toluene. By contrast, the
molecular bimetallics [AeEu(Odpp)4] (Ae=Ca, Sr, Ba) and
[BaSr(Odpp)4] 15–18 were prepared with stoichiometric
amounts of the two metals, but [AeEu(Odpp)4] (Ae=Ca,
ACHTUNGTRENNUNG
E
G
CHTUNGTRENNUNG
ACHTUNGTRENNUNG
metal–alkaline earth and alkali metal–rare earth mixed
metal cages [MM’
G
G
ACHTUNGTRENNUNG
M’=Li, Na).[24]
AHCTUNGTRENNUNG
Although molten HOdpp (m.p. 101–1038C) may act as a
solvent during the initial sequence of the metal-based reac-
tions for the syntheses of 1–13 and 15–18, fluxes (1,2,4,5-
tetramethylbenzene or 1,3,5-tri-tert-butylbenzene) were
added to most reaction mixtures to promote metal–phenol
contact and crystallisation of the products (see below). Mer-
cury was added to the reaction mixtures to assist the reac-
tion by cleaning the metal surface and to activate the metals
by forming an amalgam. Mercury was previously employed
ACHTUNGTRENNUNG
Sr) showed a degree of metal-atom disorder in the struc-
tures with an overall excess of Ae in the single crystals ex-
amined. An attempt to prepare the neutral bimetallic
[CaYb
[Ca2A(Odpp)3][Yb
in the cation positions that indicated a Yb-rich product,
whereas an attempt to prepare [CaSr(Odpp)4] failed with
ACHTUNGTRENNUNG
C
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
only a homometallic complex isolated. It is also interesting
that a 1:1 ratio of Ba metal and a rare earth metal (Ln=Sm,
Eu, Yb) to four equivalents of HOdpp consistently afforded
in the synthesis of [M2ACTHNUTRGNE(NUG Odpp)4] (M=Ca, Sr, Ba, Eu, Yb)
and the synthesis of 1, and the reaction with Yb metal was
incomplete without mercury even at higher temperatures.[11]
The preparation of charge-separated complexes 12 and 13
without mercury was attempted, but only the homometallic
the heterobimetallic molecular species [BaEu
for Ln=Eu, but for Sm and Yb the charge-separated heter-
obimetallic species [Ba2A(Odpp)3][Ln(Odpp)4] (Ln=Sm (12),
ACHTUNGTERNN(UNG Odpp)4] 18
C
ACHTUNGTRENNUNG
species [Ba
N
Yb (13)) was formed, commensurate with the decreased sta-
bility of the divalent oxidation state for Sm and Yb com-
pared with Eu.
of unreacted (presumably rare earth) metal, even after pro-
longed reaction times. This is not surprising given that Ba
metal is more electropositive than Sm and Yb. However,
the preparation of molecular bimetallics 17 and 18 proceed-
ed smoothly without mercury. Possibly, these soluble species
are more readily formed than the ionic complexes, and/or
the reactivities of the pairs of metals (Ba/Sr and Ba/Eu) are
better matched. In a similar vein, mercury activation was
not required in the synthesis of heterobimetallic alkali
metal–alkaline earth metal Odpp complexes, though these
syntheses generally did not involve two free metals.[14,15]
Differential reactivity of the two metals, either intrinsic or
arising from the nature of the metal filings, created prob-
lems generally and not just in reactions without mercury. In-
After direct reaction of the metals with HOdpp, X-ray
quality crystals of the target complexes could often be hand-
picked directly from the Carius tube (Table 1). However,
unreacted metal and small amounts of homometallic co-
products were present in reaction mixtures, necessitating
solvent extraction to obtain pure bulk samples of the target
complexes. The charge-separated heterobimetallic com-
plexes have an extremely low solubility in non-coordinating
solvents, even hot toluene, precluding their use as an extrac-
tant for these complexes. They are also extremely insoluble
in diethyl ether. Except in the case of [Ba
(Odpp)4] complexes (see below), use of thf as an extractant
led to dissociation of [(Ln’/Ae)2A(Odpp)3][Ln(Odpp)4] into
2ACHTUNGTRENN(UNG Odpp)3][Ln-
AHCTUNGTRENNUNG
itial attempts to prepare [Yb
C
ACHTUNGTRENNUNG
crystals of homometallic 1, even when using a considerable
excess of Y metal, as did an attempt to produce a Yb/Eu bi-
metallic complex. Repeating the Yb/Y synthesis by using
similar conditions, but with some variations in the work-up,
gave the bimetallic as various toluene solvates, 2·2PhMe,
2·0.5PhMe (with 25:75 Yb/Y disorder in the anion) and
2·1.5PhMe from two preparations. Greater consistency was
achieved in the other syntheses, which were generally car-
ried out in the presence of 1,3,5-tri-tert-butylbenzene as a
flux. Because of the difficulties encountered in the synthesis
homometallic complexes, as exemplified by 1 and 6 (see
below). Accordingly, to obtain pure bulk samples of the
AHCTUNGTRENNUNG
AHCTUNGTRENNUNG
1) Following extraction of the homometallic species from
the reaction product with toluene, the representative
charge-separated complexes 2, 3, 6, 7, 10–12 were ex-
tracted from the metal-containing residue by toluene
under pressure at 1908C, well above the boiling point of
Chem. Eur. J. 2009, 15, 5503 – 5519
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
5505

G. B. Deacon, P. C. Junk, K. Ruhlandt-Senge et al.
this solvent (see the Experimental Section for details).
Very slow cooling gave crystalline material, often with
single crystals of toluene solvates. The method takes ad-
vantage of the high thermal stability of these compounds
(m.p. >2508C) and enabled the yields of the compounds
to be determined.
analyses and/or metal analysis in representative cases. Satis-
factory elemental analyses were generally obtained both for
these compounds and for the soluble uncharged bimetallics,
occasionally corresponding to loss of toluene of solvation. In
the case of 2·0.5PhMe, in which Yb/Y disorder was ob-
served in the [YACTHNUTRGNEUNG
(Odpp)4]ꢀ anions of the single crystals, the
2) The [Ba
G
E
analytical data on the bulk sample were closer to the values
calculated for the undisordered composition. For complexes
15 and 16, in which single crystals were Ca- or Sr-rich owing
to Ae/Eu disorder, analyses of the bulk product were closer
to an undisordered composition for 15 but provided no clear
distinction for 16. All infrared spectra showed the features
expected for the Odpp ligand and the absence of a n(OH)
absorption was indicative of deprotonation of the phenol.
The spectra of the charge-separated species were similar but
minor differences at n˜ =1600–1500 cmꢀ1 (n(CC)) may reflect
differences in p-Ph–Ln’/Ae coordination (below).
cessfully extracted by and crystallised from toluene/thf
(see the Experimental Section) without irreversible dis-
sociation into homometallic species. On the other hand,
the more soluble neutral heterobimetallic species [AeEu-
ACHTUNGTRENNUNG
were much less soluble in toluene and were extracted
with a toluene/thf mixture. However, use of this solvent
mixture after an attempted preparation of [CaSr
led to isolation of [Sr(Odpp)2A(thf)3] 22. Thus, amongst
the present complexes, most barium-containing bimetal-
lic complexes are uniquely stable to toluene/thf with the
1
Meaningful H NMR spectra were precluded by insolubil-
ity in non-polar solvents and dissociation into homometallic
species in polar solvents. Thus, the 1H NMR spectrum of
6·PhMe (washed with toluene to remove any homometallic
impurities) in [D8]thf was a composite of those of [Ca2-
exception of [Ba
below).
Despite the insolubility of isolated [(Ln’/Ae)
G
ACHUTGTNERN(NUG Odpp)4]·PhMe and [NdACHTUNGTREN(NUGN Odpp)3] (1:1) in the same medium,
A
but confirmed the composition of the heterobimetallic com-
plex. On a preparative scale, extraction into thf and crystal-
amounts of single crystals of 2·2PhMe and 6·PhMe were de-
posited on prolonged standing from toluene that had been
used to extract homometallic species from the bulk charge-
separated products. Thus, the blue washings from a synthesis
lisation of 6·PhMe gave the known [Nd
and also colourless crystals that were unsuitable for X-ray
studies but likely to be [Ca(Odpp)2A(thf)3]. Extraction of
6·PhMe with toluene/thf 6:1 gave crystals of [Ca2A(Odpp)4-
(thf)2] 19. This ready break-up of the charge-separated spe-
cies in polar media was also exemplified by the quantitative
recovery of [Mg(Odpp)2A(thf)2] from an attempted synthesis
of 14 in toluene/thf 1:1 and isolation of [Sr(Odpp)2A(thf)3] 22
from toluene/thf following an attempted synthesis of [CaSr-
(Odpp)4]. Similarly, past attempts to prepare Li/Mg/Odpp
bimetallics in thf or diethyl ether resulted in precipitation of
ACHUTNGTNERNUG(Odpp)3HCATUNGTRENN(GUN thf)2]·2thf
A
CHTUNGTRENNUNG
of 6 initially deposited crystals of [Nd
(Odpp)3], and on fur-
CHTUNGTRENNUNG
ther standing at ꢀ208C the solution turned green and a few
crystals of 6·PhMe were also obtained. Previously, bulk 1
has been shown to give single crystals of 1·PhMe under tolu-
ene for several weeks. Possibly the [(Ln’/Ae)
ACHTUNGTRENNUNG(Odpp)4] complexes have very slight solubility in toluene, or
they can equilibrate with the corresponding homometallic
derivatives. However, attempts to prepare 2 and 6 by heat-
ing the homometallic counterparts in toluene have failed so
far, even at 1908C followed by slow cooling and prolonged
standing [Eq. (4)]. Earlier, an attempt to prepare 1·PhMe
ACHTUNGTRENNUNG
A
CHTUNGTRENNUNG
2A
A
CHTUNGTRENNUNG
ACHTUNGTRENNUNG
[MgACHTNUTRGENN(UG Odpp)2ACHTUNGTREN(NGUN solvent)2], whereas heterobimetallic species
could be prepared in toluene.[25] Furthermore, treatment of
[15]
[CsCa
similar treatment of
(Odpp)3].[11]
Two unexpected colour variations were observed in the
products. For example, [Ba2A(Odpp)3][Sm(Odpp)4] 12 hand-
A
ACHTUNGTERNN(UNG Odpp)]n and
from [Yb
unsuccessful.[11] In contrast, the Ae’/Ae complex [Ba2-
(Odpp)3][Mg(Odpp)3A(thf)] was obtained by treatment of
[Ba2A(Odpp)4] with [Mg(Odpp)2A(thf)2] in toluene [Eq. (2)],
(Odpp)4] and [Yb
(Odpp)3] in boiling toluene was
1
CHTUNGTERN(NGNU Odpp)4] and [Yb-
AHCTUNGTRENNUNG
G
A
CHTUNGTRENNUNG
G
A
G
C
ACHTUNGTRENNUNG
but the synthesis failed in toluene/thf 1:1. This is the sole
system with an anion of a divalent metal.
picked from the reaction mixture was colourless, but sol-
vates 12·PhMe and 12·4PhMe were dark green. Likewise,
single crystals of 6·PhMe deposited from toluene over a pro-
longed period were dark green, but the bulk microcrystal-
line compound was the expected blue.
½ðLn0=AeÞ2ðOdppÞ4ꢁþ
PhMe
½LnðOdppÞ3ꢁ ! ½ðLn0=AeÞ2ðOdppÞ3ꢁ½LnðOdppÞ4ꢁ
ð4Þ
190 ꢂ
C
X-ray crystallography studies: Crystalline samples of hetero-
bimetallic compounds 1–18, often as toluene solvates, of
suitable quality for X-ray structure determination were
either obtained directly from the Carius tube or were grown
from toluene (mainly after dissolution at 1908C) or toluene/
thf mixtures (see Table 1 and the Experimental Section).
Crystalline samples of homometallic compounds 19–22 were
either obtained directly from the Carius tube or grown from
Ae ¼ Ca; Ln0 ¼ Yb; Ln ¼ Nd, Y
Characterisation: Whilst X-ray crystallography provided the
primary characterisation, especially in the case of hand-
picked single crystals, the two extraction methods (above)
provided bulk samples of the charge-separated complexes
for yield determination, infrared spectroscopy and micro-
5506
www.chemeurj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 5503 – 5519

Rare Earth–Rare Earth and Alkaline Earth–Rare Earth Complexes
FULL PAPER
Table 3. Selected bond lengths [ꢁ] in neutral heterobimetallic com-
pounds.
toluene/thf mixtures (see above). Table S1 in the Supporting
Information contains a summary of relevant data collection
and refinement parameters for all compounds fully charac-
terised by X-ray crystallography. The crystal data of 1a, 1b,
2·0.5PhMe, 2·1.5PhMe and 8 were not of sufficient quality
to discuss bond lengths, but the connectivity of the mole-
cules and identity of the metal atoms was unequivocally de-
termined. Their unit cell data are included with their prepa-
rations in the Supporting Information. Complex 11·0.5PhMe
(unit cell data with the synthesis) was found to be isomor-
phous with 10·0.5PhMe, so a data collection was not under-
taken. The solid-state structures of the heterobimetallic
compounds can be classified into two structural types: 1) a
15·PhMe
M’=Eu M’=Eu M’=Eu, M’=Sr
M=Ca M=Sr M=Sr M=Ba
16
16·PhMe 17
18
M’=Eu M’=Eu
M=Ba M=Ba
18·PhMe
ꢀ
M’1 O1 2.303(3)
ꢀ
M’1 O2 2.491(3) 2.420(8) 2.417(1) 2.391(4) 2.468(2) 2.393(1)
ꢀ
M’1 O3 2.368(3) 2.417(7) 2.432(2) 2.497(4) 2.384(2) 2.425(2)
ꢀ
M’1 O4
2.444(9) 2.449(2) 2.505(4) 2.488(2) 2.478(2)
ꢀ
M1 O1
2.313(8) 2.36(1)
2.404(7) 2.43(1)
2.622(8) 2.50(1)
2.459(4) 2.480(2) 2.495(2)
2.917(4) 2.778(2) 2.931(2)
2.552(4) 2.940(2) 2.623(2)
2.762(4) 2.562(2) 2.840(2)
ꢀ
M1 O2 2.28(1)
ꢀ
M1 O3 2.30(1)
ꢀ
M1 O4 2.118(9) 2.514(8) 2.50(1)
M’1····M1 3.795(2) 3.586(2) 3.531(2) 3.8075(7) 3.8116(5) 3.8206(5)
charge-separated species containing a [(Ln’/Ae)
cation and either a [Ln
(Odpp)4]ꢀ (1–13) or [Mg
(thf)]ꢀ anion (14) or 2) a neutral dinuclear species [AeEu-
(Odpp)4] 15, 16, 18 and [BaSr(Odpp)4] 17. Selected metal–
(Odpp)3]+
(Odpp)3-
A
ACHTUNGTRENNUNG
N
Ar2)-OAr2}]2 (OAr2 =2,6-di-isopropylphenolate),[30a,b] dinu-
A
U
clear [Ln
(NHAr2)2{m-(N:h6-Ar2)-NHAr2}]2 (Ar2 =2,6-di-iso-
ACHUTGTNRENNUG CAHTUNGTRENNUGN
oxygen bond lengths for all heterobimetallic compounds are
listed in Tables 2 and 3. Bond angles are given in Tables S2
and S3 in the Supporting Information. Because the [(Ln’/
propylphenyl)[22d] and polynuclear [Ae
ACHTUNGRTNEUNG(tBu2pz)2]n (Ae=Ca,
n=3; Ae=Sr, n=4; Ae=Ba, n=6; tBu2pz=3,5-di-tert-bu-
tylpyrazolate) complexes,[30c] in which intermolecular p-Ph–
Ln/Ae interactions give rise to the dimeric/oligomeric com-
Ae)2ACHTUNGTRENNUNG
(Odpp)3]+ cations of 1–14 have solely bridging arylox-
ide ligands, the potentially naked faces of the large metal
ions are shrouded by pendant phenyl groups locked in place
by p-Ph–Ln’/Ae interactions. Likewise, the low (3,4) coordi-
plexes. In addition, there are a number of [Ln/Ae
complexes for which p-Ph–Ln/Ae interactions have been re-
ported,[11,17,29,35–37] as well as a limited number of [LnII/III
(arene)]n+ (n=2,3) complexes[22] to assist in deciding bond-
ACHTUNGTRENNUNG(Odpp)]
-
nate metals in [AeEu
G
(Odpp)4] com-
ACHTUNGTRENNUNG
plexes have similar interactions. Details of the p-Ph–Ln’/Ae
interactions are given in Tables 4 and 5. In choosing upper
limits for significant Ln/Ae···C interactions, we have used
ing limits. Conservative upper limits for Ln/Ae···C bonding
have been consistently chosen. A representative detailed
justification of limits is given for [Yb2ACTHNUTRGNEUNG
(Odpp)3]+ below.
Ln/Ae···C bond lengths in dinuclear [LnACHTNUTRGENNUG HCATUNGTRENNGUN
(OAr2)2{m-(O:h6-
Table 2. Selected bond lengths [ꢁ] in charge-separated heterobimetallic compounds.
2·2PhMe
Ae=Yb
Ln=Y
3
3·0.5PhMe
4
5
6·PhMe
Ae=Ca
Ln=Nd
7
Ae=Eu
Ln=Y
Ae=Eu1, Eu2
Ae=Eu3, Eu4
Ln=Y2
Ae=Eu1, Eu2
Ln=Nd2
Ae=Eu3, Eu4
Ln=Nd1
Ae=Eu
Ln=Ho
Ae=Ca,
Ln=Ho
Ln=Y1
ꢀ
Ln1 O1
2.120(3)
2.121(3)
2.114(3)
2.083(3)
2.356(3)
2.314(3)
2.332(3)
2.285(3)
2.324(3)
2.327(3)
3.3374(4)
2.091(3)
2.102(3)
2.089(3)
2.097(3)
2.446(3)
2.403(3)
2.452(3)
2.463(3)
2.441(3)
2.424(3)
3.5572(3)
2.147(6)
2.126(6)
2.112(6)
2.112(6)
2.444(6)
2.433(6)
2.434(6)
2.424(6)
2.474(6)
2.425(6)
3.5762(6)
2.086(7)
2.094(7)
2.086(7)
2.122(6)
2.447(6)
2.415(7)
2.474(6)
2.400(6)
2.416(7)
2.475(7)
3.5877(7)
2.198(4)
2.205(4)
2.201(4)
2.200(4)
2.420(3)
2.409(3)
2.427(3)
2.441(3)
2.426(4)
2.452(3)
3.5810(4)
2.237(4)
2.191(4)
2.209(4)
2.228(4)
2.474(4)
2.445(4)
2.369(4)
2.403(4)
2.403(4)
2.500(3)
3.5561(4)
2.105(1)
2.090(1)
2.092(1)
2.098(1)
2.449(1)
2.404(1)
2.453(1)
2.464(1)
2.440(1)
2.429(1)
3.5562(2)
2.215(3)
2.189(3)
2.193(3)
2.233(3)
2.293(3)
2.269(3)
2.289(3)
2.267(3)
2.258(3)
2.265(3)
3.231(2)
2.107(3)
2.096(3)
2.101(3)
2.118(3)
2.256(4)
2.275(3)
2.304(3)
2.316(3)
2.263(4)
2.278(3)
3.224(2)
ꢀ
Ln1 O2
ꢀ
Ln1 O3
ꢀ
Ln1 O4
ꢀ
Ae1 O5
ꢀ
Ae1 O6
ꢀ
Ae1 O7
ꢀ
Ae2 O5
ꢀ
Ae2 O6
ꢀ
Ae2 O7
Ae1····Ae2
9
10·0.5Ph
Ae=Sr1, Sr2 Ae=Sr3, Sr4
12
Ae=Ba
Ln=Sm
12·PhMe
Ae=Ba
Ln=Sm
12·4PhMe
Ae=Ba
Ln=Sm
13
Ae=Ba
Ln=Yb
14
Ae=Ba
Ln=Mg
Ae=Ca
Ln=Yb
Ln=Nd1
Ln=Nd2
ꢀ
Ln1 O1
2.064(3)
2.062(3)
2.084(3)
2.068(3)
2.28(2)
2.30(2)
2.33(2)
2.33(2)
2.28(2)
2.29(2)
3.29(3)
2.188(9)
2.194(8)
2.235(8)
2.230(8)
2.440(9)
2.38(1)
2.54(1)
2.422(9)
2.45(1)
2.189(9)
2.215(9)
2.20(1)
2.171(3)
2.179(3)
2.196(3)
2.185(3)
2.520(3)
2.649(3)
2.683(3)
2.630(3)
2.595(3)
2.544(3)
3.8808(4)
2.166(3)
2.149(3)
2.151(3)
2.196(3)
2.608(3)
2.644(3)
2.565(3)
2.608(3)
2.547(2)
2.682(3)
3.9019(7)
2.144(3)
2.173(3)
2.163(3)
2.159(3)
2.640(3)
2.575(3)
2.587(3)
2.575(3)
2.621(3)
2.643(3)
3.8857(5)
2.060(2)
2.071(2)
2.058(2)
2.053(2)
2.556(2)
2.631(2)
2.610(2)
2.642(2)
2.623(2)
2.595(2)
3.8647(4)
1.892(4)
1.870(4)
1.869(4)
2.042(5)
2.627(4)
2.590(4)
2.602(4)
2.607(4)
2.571(4)
2.597(4)
3.8980(6)
ꢀ
Ln1 O2
ꢀ
Ln1 O3
ꢀ
Ln1 O4
2.14(1)
ꢀ
Ae1 O5
2.430(8)
2.477(8)
2.394(9)
2.42(1)
2.397(8)
2.410(9)
3.546(2)
ꢀ
Ae1 O6
ꢀ
Ae1 O7
ꢀ
Ae2 O5
ꢀ
Ae2 O6
ꢀ
Ae2 O7
2.47(1)
3.559(2)
Ae1····Ae2
Chem. Eur. J. 2009, 15, 5503 – 5519
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
5507

G. B. Deacon, P. C. Junk, K. Ruhlandt-Senge et al.
Table 4. Metal–carbon lengths [ꢁ] for p-Ph–metal interactions in charge-separated heterobimetallic compounds.
2·2PhMe
3
3·0.5PhMe
4
5
6·PhMe
7
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Yb1 Cn
Eu1 Cn
Eu1 Cn
Eu3 Cn
Eu1 Cn
Eu3 Cn
Eu1 Cn
Ca1 Cn
Ca1 Cn
h4:h1:h3
h1:h6:h3
h3:h6:h1
h2:h3:h3
h2:h5:h2
h4:h3:h1
h1:h6:h3
h1:h2:h6
h1:h6:h3
C85 2.887(5) C80 3.047(5) C73 3.21(1) C205 3.11(1) C79 3.211(5) C199 3.052(6) C84 3.058(2) C80 3.026(5) C80 3.082(5)
C86 3.190(5) C103 3.032(5) C79 3.03(1) C206 3.13(1) C80 2.977(5) C204 3.233(6) C103 3.037(2) C103 3.176(6) C103 2.961(5)
C89 3.071(5) C104 3.074(5) C80 3.20(1) C229 3.23(1) C103 3.077(5) C211 2.931(6) C104 3.093(2) C108 2.943(5) C104 3.019(5)
C90 2.826(5) C105 3.168(5) C103 2.97(1) C233 3.26(1) C104 3.233(7) C212 3.089(6) C105 3.179(2) C115 2.896(5) C105 3.077(6)
C102 2.964(5) C106 3.217(5) C104 3.05(1) C234 3.19(1) C106 3.266(6) C229 2.990(5) C106 3.204(2) C116 2.903(5) C106 3.054(5)
C109 3.132(5) C107 3.175(5) C105 3.20(1) C241 3.12(1) C107 3.100(5) C230 3.068(5) C107 3.162(2) C117 2.997(5) C107 3.005(5)
C121 3.038(4) C108 3.082(5) C106 3.26(1) C245 3.24(1) C108 2.996(5) C234 3.242(5) C108 3.071(2) C118 3.080(5) C108 2.955(5)
C126 3.106(5) C115 3.237(5) C107 3.21(1) C246 2.97(1) C125 3.270(5) C242 2.953(5) C115 3.227(3) C119 3.091(5) C109 3.073(5)
C116 2.910(4) C108 3.04(1)
C117 3.206(5) C122 3.08(1)
C126 2.967(5)
C119 3.204(2) C120 2.988(5) C115 3.032(5)
C120 2.913(2)
C116 3.089(5)
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Yb2 Cn
Eu2 Cn
Eu2 Cn
Eu4 Cn
Eu2 Cn
Eu4 Cn
Eu2 Cn
Ca2 Cn
Ca2 Cn
h1:h6:h1
h4:h2:h1
h3:h1:h4
h3:h2:h1
h3:h2:h2
h2:h2:h2
h5:h2:h1
h1:h6:h1
h6:h1:h1
C80 2.986(4) C85 2.990(4) C85 3.16(1) C211 3.19(1) C85 3.126(5) C205 3.184(5) C85 2.993(2) C86 2.871(5) C85 2.859(5)
C103 2.877(4) C86 3.034(4) C89 3.25(1) C212 3.12(1) C86 3.183(5) C210 3.057(6) C86 3.114(2) C97 2.961(5) C86 2.922(5)
C104 2.960(5) C87 3.203(5) C90 3.12(1) C213 3.21(1) C90 3.192(5) C223 3.250(7) C87 3.277(3) C98 3.038(6) C87 3.102(6)
C105 3.062(5) C90 3.106(5) C98 3.01(1) C223 3.08(1) C97 3.228(6) C224 3.122(5) C89 3.201(2) C99 3.132(5) C88 3.176(6)
C106 3.063(5) C97 3.217(4) C115 3.02(1) C228 3.04(1) C98 3.137(5) C247 3.006(7) C90 3.036(2) C100 3.127(5) C89 3.106(5)
C107 2.979(5) C98 3.109(4) C116 3.06(1) C248 2.98(1) C115 3.139(5) C248 3.011(7) C97 3.210(2) C101 3.034(5) C90 2.937(5)
C108 2.901(5) C122 3.023(5) C117 3.27(1)
C116 3.139(5)
C98 3.106(2) C102 2.946(5) C98 2.924(5)
C126 3.031(2) C122 3.079(4) C122 2.860(5)
C116 2.864(5)
C120 3.17(1)
9
10·0.5PhMe
12
12·PhMe
12·4PhMe
13
14
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Ca1 Cn
Sr1 Cn
Sr3 Cn
Ba1 Cn
Ba1 Cn
Ba1 Cn
Ba1 Cn
Ba1 Cn
h1:h6:h3
h2:h2:h3
h5:h1:h2
h3:h6:h4
h3:h4:h4
h3:h4:h4
h6:h3:h3
h6:h3:h4
C80
3.06(2) C79
3.17(1) C211 3.19(1) C85
3.11(1) C212 3.26(1) C86
3.331(4) C79
3.357(4) C80
3.441(4) C81
3.303(4) C79
3.288(5) C85
3.209(5) C86
3.312(5) C87
3.272(4) C88
3.281(4) C89
3.460(4) C90
3.215(3) C65
3.249(6)
C103 2.94(2) C80
C104 2.99(2) C103 3.25(2) C214 3.29(2) C90
C105 3.04(2) C104 3.27(2) C215 3.23(2) C103 3.229(4) C97
C106 3.02(2) C115 3.13(2) C216 3.18(2) C104 3.344(5) C98
C107 2.99(2) C116 3.02(2) C224 3.02(1) C105 3.399(4) C99
3.226(4) C80
3.354(4) C81
3.183(4) C97
3.177(4) C98
3.415(5) C99
3.253(3) C66
3.337(3) C67
3.357(3) C68
3.335(3) C69
3.259(3) C70
3.342(6)
3.438(6)
3.449(6)
3.363(5)
3.258(5)
3.247(6)
3.368(6)
3.163(5)
C108 2.95(2) C117 3.28(2) C247 3.09(1) C106 3.365(4) C102 3.449(4) C102 3.429(4) C103 3.409(3) C83
C109 3.09(2)
C115 3.02(2)
C120 3.07(2)
C248 3.09(1) C107 3.292(4) C115 3.320(4) C115 3.265(4) C107 3.462(3) C87
C108 3.208(4) C116 3.456(4) C116 3.208(4) C108 3.159(3) C88
C121 3.158(4) C119 3.457(4) C117 3.344(4) C121 3.285(3) C107 3.234(7)
C122 3.425(4) C120 3.318(4) C120 3.425(5) C125 3.260(3) C108 3.408(6)
C125 3.434(4)
C126 3.179(4)
C126 3.077(3) C111 3.412(6)
C112 3.220(7)
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Ca2 Cn
Sr2 Cn
Sr4 Cn
Ba2 Cn
Ba2 Cn
Ba2 Cn
Ba2 Cn
Ba2 Cn
h6:h1:h1
h4:h2:h1
h3:h6:h1
h4:h3:h2
h4:h6:h4
h4:h6:h3
h4:h4:h3
h3:h4:h3
C85
C86
C87
C88
C89
C90
2.84(2) C85
3.16(1) C199 3.23(1) C73
3.27(2) C205 3.08(2) C79
3.22(2) C206 3.12(2) C80
3.11(2) C229 2.99(2) C84
3.07(1) C230 3.07(2) C97
3.446(4) C85
3.137(4) C86
3.195(4) C89
3.426(4) C90
3.229(4) C85
3.259(4) C79
3.245(3) C71
3.251(8)
2.90(2) C86
3.06(2) C89
3.14(2) C90
3.08(2) C97
2.92(2) C98
3.338(4) C86
3.449(4) C87
3.268(5) C90
3.236(4) C80
3.386(4) C81
3.429(4) C84
3.242(3) C72
3.441(3) C76
3.472(3) C89
3.205(3) C90
3.314(3) C91
3.274(9)
3.414(4)
3.270(6)
3.298(4)
3.444(4)
3.363(4)
3.282(4) C103 3.287(4) C103 3.218(4) C97
3.05(1) C231 3.20(2) C101 3.390(4) C104 3.285(4) C104 3.299(4) C98
C102 2.91(2) C122 2.94(1) C232 3.26(2) C102 3.233(4) C105 3.385(4) C105 3.409(4) C101 3.419(3) C94
C122 2.85(2)
C233 3.19(2) C115 3.394(4) C106 3.473(4) C106 3.437(5) C102 3.253(3) C101 3.291(7)
C234 3.06(2) C120 3.386(4) C107 3.476(4) C107 3.362(5) C115 3.314(3) C105 3.436(4)
C242 3.10(1)
C108 3.370(4) C108 3.251(4) C116 3.222(3) C106 3.160(5)
C109 3.401(4) C121 3.261(4) C117 3.351(3)
C121 3.160(4) C125 3.391(4)
C122 3.439(4) C126 3.164(4)
C126 3.180(4)
Charge-separated
complexes
[(Ln’/Ae)
G
each metal atom. Except for the [Yb
1·PhMe,[11] all of the few previous examples of the [MM’
ACHTUNGTRENNUNG
(Odpp)3]+ cation in
(m-
(Odpp)4] (1–13) and [Ba
2A(Odpp)3][Mg
A
The heterobimetallic complexes 1–14 all feature a charge-
separated ion pair, as displayed in the structure of 2·2PhMe
Odpp)3] structural motif have involved two different metals
(M¼M’) in molecular bimetallics (see the Introduction Sec-
(Figure 1). The [M
2A
tion). The [LnACTHNGUTERNNUG
(Odpp)4]ꢀ anion consists of four terminal aryl-
aryloxide ligands with trigonal-pyramidal geometry around
oxide ligands arranged around the metal centre in a slightly
5508
www.chemeurj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 5503 – 5519

Rare Earth–Rare Earth and Alkaline Earth–Rare Earth Complexes
FULL PAPER
Table 5. Metal–carbon lengths [ꢁ] for p-Ph–metal interactions in neutral heterobimetallic compounds.
tal Section in the Supporting
Information). For brevity the
complexes are discussed in
groups containing the same
cation.
15·PhMe
16
16·PhMe
17
18
18·PhMe
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Ca1 Cn
Sr1 Cn
Sr1 Cn
Ba1 Cn
Ba1 Cn
Ba1 Cn
h6:h1
h1:h1
h1:h1:h1
h2:h1:h1
h1:h2:h1
h2:h1:h2
C221 2.85(1)
C222 2.89(1)
C223 3.00(1)
C224 3.10(1)
C225 3.10(1)
C226 2.98(1)
C422 3.17(1)
C222 3.156(6) C226 3.22(1)
C422 3.293(8) C322 3.09(1)
C426 3.23(1)
C221 3.388(6) C226 3.199(3) C221 3.351(3)
C226 3.338(6) C321 3.379(3) C222 3.329(3)
C326 3.285(6) C326 3.355(3) C322 3.349(3)
C426 3.203(6) C426 3.273(3) C422 3.246(3)
C423 3.317(3)
Structures containing
a [Yb2-
AHCTUNGTRENNUNG
1a and 1b both contain two
crystallographically independ-
ent [Yb
(Odpp)3]+ cations and
2ACHTUNGTRENNUNG
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Eu1 Cn
Eu1 Cn
Eu1 Cn
Sr1 Cn
Eu1 Cn
Eu1 Cn
h2:h3
h3:h2:h3
h2:h2:h3
h3:h5
h5:h3
h1:h1:h4
[Yb
AHCTUNGTRENNUNG
C161 3.168(4) C21
3.141(9) C261 3.021(2) C361 3.003(6) C261 3.052(3) C262 3.112(3) asymmetric unit, but the unit
C162 3.022(4) C261 3.045(9) C262 3.107(2) C362 3.285(6) C262 3.146(3) C361 3.015(3)
C261 2.998(3) C262 3.236(9) C361 3.027(2) C366 3.223(6) C263 3.277(3) C461 3.020(3)
C265 3.050(4) C361 3.091(9) C362 3.006(2) C461 3.084(6) C265 3.241(4) C462 3.187(3)
cell dimensions are different
(see the Supporting Informa-
tion Experimental Section).
Otherwise, 1a and 1b are com-
C266 2.839(4) C366 3.155(9) C41
3.261(2) C462 3.122(6) C266 3.097(3) C465 3.181(3)
C461 3.035(9) C461 2.991(2) C463 3.257(6) C461 3.010(3) C466 3.007(3)
C462 3.125(8) C466 3.171(2) C465 3.270(7) C462 3.209(3)
parable to [Yb
(Odpp)4]·PhMe
The crystal
(Odpp)3][Yb-
(1·PhMe).[16]
structure of
C466 3.184(9)
C466 3.164(6) C466 3.292(3)
AHCTUNGTRENNUNG
2·0.5PhMe revealed two similar
but crystallographically inde-
pendent [Yb2ACTHNUTRGENNUG ACHTUGNTRENNUGN
(Odpp)3]+ cations and [Y(Odpp)4]ꢀ anions and
also toluene of solvation. Both anion-metal positions in
2·0.5PhMe were found to be disordered Y/Yb approximate-
ly 70:30. Disorder in the metal positions of heterobimetallic
complexes containing the Odpp ligand has previously been
observed in the structures of [KBa
[KSr
(Odpp)3]·PhMe,[15] in which the metal positions were
disordered K/Ba and K/Sr 50:50. The crystal structures of
2·1.5PhMe and 2·2PhMe contain a [Yb2A(Odpp)3][Y(Odpp)4]
(Odpp)3]·PhMe[14] and
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
C
ACHTUNGTRENNUNG
molecule and one-and-a-half or two toluene molecules of
solvation and have no metal position disorder. In the cation
Figure 1. Structure of [Yb2ACHTNUTRGENNUG(Odpp)3][YACHTUTGNREN(NGUN Odpp)4]·2PhMe, 2·2PhMe. Hydro-
gen atoms and toluene molecules of solvation are omitted for clarity.
ꢀ
of 2·2PhMe, Yb O bond lengths (2.285(3)–2.356(3) ꢁ)
result in a Yb···Yb separation of 3.337(1) ꢁ. These bond
lengths and the Yb···Yb separation are comparable with the
analogous lengths in the structure of 1·PhMe,[11] (2.289(7)–
distorted tetrahedral geometry. No p-Ph–metal interactions
are evident in the anion because the substantial steric bulk
of four aryloxide ligands sufficiently shields the metal centre
ꢀ
2.327(7) ꢁ for Yb O and 3.348(1) ꢁ for Yb···Yb). In the
4
1
3
(Odpp)3]+ cation of 2·2PhMe, Yb1 has h :h :h -Ph Yb
ꢀ
[Yb
ꢀ
despite the low coordination number. The [Ln
anion has been previously observed in the structures of
1·PhMe,[11] [Na{Nd(Odpp)4}],[26,27] [K{Ln
(Odpp)4}] (Ln=La,
Nd),[28] [Na (Odpp)4][27] and [Na
(dme)3][Nd (dig)2][Ln-
(Odpp)4] (Ln=Nd, Er),[27] a quite limited collection.
Although the structure of the [(Ln’/Ae)2A
(Odpp)3]+ cations
A
interactions (Yb C 2.83(1)–3.19(1) ꢁ) whereas Yb2 displays
1
1
ꢀ
h :h :h interactions (Yb C 2.86(1)–3.06(1) ꢁ). In the [Yb2-
A
U
(Odpp)3]+ cation of 1·PhMe, the two metals exhibit h6:h1:h1
ACHTUNGTRENNUNG
ꢀ
G
T
ACHTUNGTRENNUNG
and h6:h2:h1 interactions[11] with Yb C interactions (2.85(1)–
3.15(1) ꢁ) comparable to those of 2·2PhMe. The longest
ACHTUNGTRENNUNG
ꢀ
G
Yb C length in 2·2PhMe that is classified as bonding
in 1–14 appear to be similar, there are some notable differ-
ences. The structures display variations in the magnitude of
the p-Ph–metal interactions. These are not entirely due to
differences in the ionic radii of the metal because slight var-
iations are also evident between different structures that
contain the same cation, and are associated with differences
in the orientation of the aryloxides and pendant phenyl
groups relative to the metal atoms. The slight differences in
the cations, which in turn affect the packing of the mole-
cules in the crystal structure, may account for the wide
range of unit cell dimensions observed for 1–14 (see the Ex-
perimental Section herein and Table S1 and the Experimen-
(3.19(1) ꢁ) is close to the maximum bonding length in
1·PhMe (3.15(1) ꢁ) and is also similar to the maximum p-
Ph–Yb interaction distance in the structure of [YbIII-
AHCTUNGTRENNUNG
(Odpp)3] (3.15(1) ꢁ),[29] despite the approximately 0.15 ꢁ
larger ionic radius of Yb2+ compared with Yb3+ (for the
same coordination number).[21] Considering the approxi-
mately 0.04 ꢁ larger ionic radius of Yb2+ than Nd3+, the
maximum p-Ph–Yb interaction distance of 3.19(1) ꢁ in
2·2PhMe is comparable with the maximum p-Ph–Nd inter-
action distance of 3.18(1) in the structure of [{Nd-
A
{O:h6-Ar2}-OAr2)}2].[30] In the cation of 2·2PhMe
ACHTUNGTRENNUNG
Chem. Eur. J. 2009, 15, 5503 – 5519
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
5509

G. B. Deacon, P. C. Junk, K. Ruhlandt-Senge et al.
Supporting Information), but there often appears to be a
correlation between the hapticity of the p-Ph–Yb interac-
tions and the angle; for example, aryloxide ligand O6 is
bound h1 to Yb1 and h6 to Yb2, and the Yb1-O6-C91 angle
is 138.0(3)8 whereas the Yb2-O6-C91 angle is 129.9(3)8. The
greater tilt towards Yb2 presumably relates to the more sub-
stantial p-Ph–Yb interaction with Yb2.
ligand between the two europium metal atoms. This con-
ꢀ
trasts with the wider range of Eu O
G
in [Eu
2A
there is a terminal aryloxide ligand on Eu1 and a difference
in coordination number between the two Eu atoms. The Eu-
O-Eu and O-Eu1,2-O angles (see the Supporting Informa-
tion) resemble the corresponding angles in the [Yb2-
The X-ray data unequivocally show that the metal posi-
(Odpp)3]+ cations, which indicates a similar ligand arrange-
ACHTUNGTRENNUNG
tion in the anion in 2·2PhMe contains Y3+ rather than Yb3+.
ment around the lanthanoid metals in the two cations.
The average Yb O bond length in the [Yb
(Odpp)4]ꢀ anion
In the structure of 3, the p-Ph–Ln interactions are similar
ꢀ
of 1·PhMe is 2.07 ꢁ, whereas for 2·2PhMe the average Y O
bond length is 2.11 ꢁ. Subtraction of the four-coordinate
ionic radius of the Ln3+ ion (extrapolated from Shannonꢂs
to those observed in [Yb2ACTHNGUTERNNUG
(Odpp)3]+ cations (see Table 4).
ꢀ
Eu1 is bound in a h1:h6:h3 fashion, whereas Eu2 has h4:h2:h1
interactions. The p-Ph–Eu contacts range from 2.910(4) to
3.237(5) ꢁ and agree well with the range of p-Ph–Eu inter-
data)[16] from the average Ln O bond length of [Ln-
ꢀ
(Odpp)4]ꢀ gives 1.31 ꢁ for Yb3+ in 1·PhMe and 1.33 ꢁ for
actions in [Eu2ACTHNGUTERNNUG
(Odpp)4]·PhMe (2.987(4)–3.240(4) ꢁ).[11] De-
Y3+ in 2·2PhMe.
spite the larger size of Eu2+ compared with Yb2+, shielding
of the naked faces does not involve significantly enhanced
Structures containing a [Eu
G
N
p-bonding. This contrasts with [Ba
(Odpp)4]·PhMe[11] in which similar structural frameworks
have more extensive p-Ph–metal interactions for the larger
Ba atoms. Similarly, in the three [M{Nd
(Odpp)4}],[26–28]
[MAe(Odpp)3] and [Li2Ae
(Odpp)4][14,15] (M=Na, K; Ae=
(Odpp)4][17] and [Eu2-
2ACHTUNGTRENNUNG
(Odpp)3]+ cations in the structures of
3
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
A
ACHTUNGTRENNUNG
Ca, Sr, Ba) series, different p-Ph–metal interactions were
observed for different metals with the same structural
framework. In cation 2 (Eu3 and Eu4) of 4, there is a signifi-
ꢀ
ꢀ
cant difference in the Eu O14 bond lengths (Eu3 O14
ꢀ
2.369(4) ꢁ, Eu4 O14 2.500(3) ꢁ), with both being outside
ꢀ
the Eu O range of 3. This asymmetric binding mode is un-
expected given that pendant phenyl groups on the O14
ligand bind only h1 to Eu3 and h2 to Eu4. Nevertheless, the
O14 ligand is markedly tilted towards Eu4 (Eu3-O14-C235
143.8(3)8; Eu4-O14-C235 119.6(3)8). Thus the variation in
Figure 2. Structure of the [Eu
[Y(Odpp)4], 3. Hydrogen atoms are omitted for clarity.
(Odpp)3]+ cation in [Eu
2ACHTUNTGRENNUG 2CAHTUNGTRNEN(UGN Odpp)3]
ACHTUNGTRENNUNG
ꢀ
Eu O14 bond length is likely to be a result of enhanced
steric crowding around Eu4.
The [YACHTNUGRTNEUNG
(Odpp)4]ꢀ anions in 3 and 3·0.5PhMe are very sim-
comparable bond lengths (Table 2). The fundamental struc-
tural framework of the cations in these structures is similar
ilar and the bond lengths and angles around the Y metal
atom are in agreement with the same anion of 2·2PhMe.
to that of [Yb
2A
The [NdACHTUGNTRENNUG ACHTUNGTRENNUNG
(Odpp)4]ꢀ and [Ho(Odpp)4]ꢀ anions in the struc-
[Eu2A
N
U
tures of 4 and 5, respectively, also display slightly distorted
In 3·0.5PhMe, two similar but crystallographically independ-
ent cations and anions and a molecule of toluene are pres-
tetrahedral geometry around the metal atom with, as ex-
ꢀ
pected, different Ln O bond lengths (averages 2.096 ꢁ for
ent in the asymmetric unit. In addition to the [Eu
cation, the structures of 4 and 5 contain [Nd
(Odpp)4]ꢀ and
[Ho
(Odpp)4]ꢀ anions, respectively, with the structure of 4
having two crystallographically independent [Eu2A
(Odpp)3]+
cations and [Nd
(Odpp)4]ꢀ anions in the asymmetric unit.
Only the representative [Eu2A
(Odpp)3]+ cation in 3 is dis-
cussed in detail, but the cation in 4, which displays the great-
C
[Ho
[Nd
radius of the Ln3+ ion (extrapolated)[16] from the Ln O
bond lengths in [Ln
(Odpp)4]ꢀ gives 1.31 ꢁ for 5 and 1.34
and 1.36 ꢁ for anion 1 and anion 2, respectively, of 4.
A
N
(Odpp)4]ꢀ). Subtraction of the four-coordinate ionic
ACHTUNGTRENNUNG
ꢀ
ACHTUNGTRENNUNG
R
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
CTHUNGTRENNUNG
Structures containing a [Ca2ACHTUNGTRENNUNG
(Odpp)3]+ cation: The [Ca2-
ACHTUNGTRENNUNG
(Odpp)3]+ cations in the crystal structures of 6·PhMe, 7 and
ꢀ
est variation in Eu O bond lengths, is also briefly consid-
ered.
9 are very similar, as seen from the pertinent bond lengths
listed in Table 2. Consequently, only the structure of the
cation of 6·PhMe is discussed in detail. In the structure of 9,
both metal positions in the cation are disordered Ca/Yb
70:30, which perhaps arises from the similarities in ion size,
but the anion is not disordered. The bond lengths in the
cation of 6·PhMe correlate quite well with the analogous
ꢀ
In the structure of 3, Eu O bond lengths in the cation
range from 2.403(1) to 2.463(1) ꢁ (average 2.44 ꢁ), which is
ꢀ
in good agreement with the Yb O bond lengths in the [Yb2-
A
ionic radii between Eu2+ and Yb2+
(Odpp)3]+ cations, the narrow range of Eu O bond lengths
in 3 indicates near-symmetrical bridging of the aryloxide
.
As with the [Yb2-
[16]
ꢀ
ACHTUNGTRENNUNG
values in [Yb2ACTHNUTRGNEUNG
(Odpp)3]+ cations (Table 3), further reflecting
5510
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ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 5503 – 5519

Rare Earth–Rare Earth and Alkaline Earth–Rare Earth Complexes
FULL PAPER
[16]
the similar ionic radii of Ca2+ and Yb2+
.
The Ca1 O and
ꢀ
ꢀ
Ca2 O bond lengths (2.269(3)–2.293(3) ꢁ; 2.258(3)–
2.267(3) ꢁ) indicate near symmetric binding of the aryloxide
ꢀ
ligands and are similar to bridging Ca O bond lengths
(2.249(2)–2.275(2) ꢁ)
in
the
structure
of
[Ca2-
ACHTUNGTRENNUNG
CTHUNGTRENNUNG
(3.582(1) ꢁ) is most likely due to the additional bridging ar-
yloxide ligand in 6·PhMe. The Yb···Yb lengths in [Yb2-
Figure 3. Structure of the [Sr
[Nd(Odpp)4]·0.5PhMe (10·0.5PhMe). Hydrogen atoms and toluene mole-
cule of solvation are omitted for clarity.
(Odpp)3]+ cation (cation 1) in [Sr
2ACHTUNTGRENNUG 2ACHTUNGTRENNUNG(Odpp)3]
ACHTUNGTRENNUNG
(Odpp)4]·1.5PhMe and 1·PhMe show a similar trend.[11]
AHCTUNGTRENNUNG
The shrouding pendant phenyl groups bind h1:h2:h6 to Ca1
1
1
6
ꢀ
and h :h :h to Ca2. Ca C interaction distances range from
2.871(5) to 3.176(6) ꢁ, with the upper value agreeing well
with that for p-Ph–Yb bonding in 2·2PhMe (3.190(5) ꢁ).
The donor hapticities of 6·PhMe and 1·PhMe are the same
and their unit cell dimensions are similar, which is consistent
with the above suggestion that the large number of different
ꢀ
tive cations. These differences may explain the smaller Sr O
bond length range and shorter Sr···Sr length for cation 2
compared with cation 1. Cation 2 has very similar p-Ph–
metal interactions to 3 whereas cation 1 has lower hapticity;
this is another example showing the flexibility of p-Ph–
metal interactions. Due to the absence of terminal ligands,
unit cell dimensions observed for the [(Ln’/Ae)
2ACHTUNGTNER(NUNG Odpp)3]
[Ln(Odpp)4] complexes may be linked to differences in p-
ACHTUNGTRENNUNG
Ph–metal interactions. The similarities between the p-Ph–
metal interactions of 6·PhMe and 1·PhMe contrast with the
differences in p-Ph–metal interactions between structurally
the [Sr
tensive p-Ph–Sr interactions than the structure of [Sr2-
(Odpp)4]·PhMe (h1:h1:h1) at Sr1 and (h2:h2:h2) at Sr2.[17] The
(Odpp)3]+ cations in 10·0.5PhMe display more ex-
2ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
ꢀ
similar [Ca
(Odpp)4]·1.5PhMe (h4:h3 and h1:h6).[11] Enhanced p-bonding
in [Ca2A 2A(Odpp)4]·PhMe can be
(Odpp)3]+ compared with [Ca
C
Sr C bond lengths in 10·0.5PhMe are slightly longer than
E
those in [Sr2A(Odpp)4]·PhMe, but are in good agreement with
CHTUNGTRENNUNG
ꢀ
C
U
the Sr C lengths in the structure of [NaSrACTHNGUETRNNU(G Odpp)3]·PhMe
attributed to the absence of terminal ligands in the former
(3.051(2)–3.310(3)).[15] In 10·0.5PhMe the angle Sr4-O12-
C199 (115.7(8)8) is much smaller than Sr3-O12-C199
(139.3(9)8), which indicates that the ligand is tilted towards
as well as the cationic nature.
ꢀ
The average Ln O bond lengths in the [Nd
G
ꢀ
ꢀ
(2.208 ꢁ), [Ho
A
U
Sr4. However, the Sr3 O12 and Sr4 O12 bond lengths are
comparable and, surprisingly, ligand O12 displays more ex-
tensive p-Ph–Sr interactions with Sr3 than with Sr4 (h5 vs.
h3). The tilting of ligand O12 towards Sr4 may permit the
two pendant phenyl groups of ligand O12 to adopt the most
favourable positions for optimising p-Ph–Sr interactions
(2.070 ꢁ) anions of 6·PhMe, 7 and 9, respectively, compare
well with the previously discussed [Ln
AHCTUNGTRENNUNG
traction of the ionic radius of the relevant four-coordinate
Ln3+ ion (extrapolated)[16] from the average Ln O bond
ꢀ
lengths in the [Ln
N
ꢀ
and 1.32 ꢁ for the anions in 6·PhMe, 7 and 8, respectively.
with both metals. The average Nd O bond lengths of the
[Nd
A
Structures containing a [Sr2A
(Odpp)3]+ cation: The crystal
those of [NdACTHUNGTRENNUNG
structure of 10·0.5PhMe revealed two similar but crystallo-
graphically independent [Sr2A
(Odpp)3]+ cations and [Nd-
(Odpp)4]ꢀ anions and one toluene molecule in the lattice.
G
Structures containing a [Ba
ACHTUNGTRENNUNG
2ACHTUNGTRENNUNG
E
The Ho3+ analogue, 11·0.5PhMe, is isomorphous. The Sr O
12·4PhMe, 13 and 14 (Figure 4) are very similar, as seen
from the pertinent bond lengths listed in Table 2. The anion
in the crystal structures of 12, 12·PhMe and 12·4PhMe is
ꢀ
bond lengths in the [Sr2A
CTHUNGTRENNUNG
range from 2.38(1) to 2.54(1) ꢁ (average 2.45 ꢁ) for
cation 1 (Sr1 and Sr2) and 2.394(9) to 2.477(8) ꢁ (average
2.42 ꢁ) for cation 2 (Sr3 and Sr4). Due to the comparable
[16]
ionic radii of Sr2+ and Eu2+
,
the average Sr O bond
ꢀ
ꢀ
lengths correlate well with the average Eu O bond length
(2.44 ꢁ) in 3, although the bond length range for
10·0.5PhMe is wider than for 3. In the structure of [Sr2-
ACHTUNGTRENNUNG
(Odpp)4]·PhMe,[17] which contains three bridging ligands and
ꢀ
one terminal ligand, the Sr O bond lengths (2.430(2)–
2.499(2) ꢁ) for the bridging aryloxides are close to the anal-
ogous values for 10·0.5PhMe.
In 10·0.5PhMe, p-Ph–Sr interactions are h2:h2:h3 for Sr1,
h4:h2:h1 for Sr2 (cation 1, Figure 3), h5:h2:h1-Ph–Sr for Sr3
3
6
1
ꢀ
and h :h :h for Sr4 (cation 2). The Sr C lengths range from
Figure 4. Structure of [Ba
atoms are omitted for clarity.
2ACHTUGNTRENU(NGN Odpp)3][MgACHTUNRTGEGNUN(N Odpp)3CAHTNUGTRNEN(UGN thf)] (14). Hydrogen
2.94(1) to 3.28(2) ꢁ and 2.99(1) to 3.29(2) ꢁ for the respec-
Chem. Eur. J. 2009, 15, 5503 – 5519
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
5511

G. B. Deacon, P. C. Junk, K. Ruhlandt-Senge et al.
[Sm
G
ACHTUNGTRENNUNG
phenolate),[31] or a bidentate donor, as in [Mg(OAr3)2-
the charge-separated complexes, whereas the anions in 13
N
(tmeda=N,N,N’,N’-tetramethylethylenedia-
and 14 are [Yb
G
E
U
ꢀ
tively. Ba O bond lengths in 12·PhMe, 13 and 14 fall within
a narrow range (2.556(2)–2.682(3) ꢁ, Table 2) and are com-
(OAr4 =2,6-di-tert-butyl-4-methylphenolate).[25]
parable with those in [M{Ba
N
[Ba2ACHTUNGTRENNUNG
(Odpp)4],[17] the Ba O bond lengths (2.506(2)–
ꢀ
2.887(2) ꢁ) for the bridging ligands have a larger range, per-
haps owing to the presence of a terminal Odpp ligand on
Ba1. The trigonal-pyramidal arrangement and more sym-
A
metrical bridging of the metal atoms in the [Ba
ꢀ
ꢀ
cation is characterised by a narrower range of O-Ba-O
(68.18(8)–71.68(9)8) and Ba-O-Ba (94.72(6)–98.1(1)8) angles
difference. The Mg Odpp and Mg O
14 (average 1.88 and 2.04 ꢁ, respectively) are comparable
with those in [Mg(Odpp)2A(thf)2] (average 1.88 and 2.03 ꢁ)
and [Mg(Odpp)2A
(Et2O)2] (average 1.88 and 2.04 ꢁ).[25]
ACHTUNGTREN(NUNG thf) bond lengths in
in 12·PhMe, 13 and 14 than in [Ba
N
N
CHTUNGTRENNUNG
G
CHTUNGTRENNUNG
Neutral dinuclear complexes [AeEu
(Odpp)4]
ACHTUNGTERN(NGNU Odpp)4] and [BaSr-
than in [Ba
N
ACHTUNGTRENNUNG
differences in p-Ph–Ba interactions between the two struc-
tures. An opposite trend was observed when comparing the
The structure of [CaEuACTHNGUTER(NNUG Odpp)4] (15): The structure of
Eu···Eu and Sr···Sr lengths in the [Eu
and the [Sr2A
(Odpp)3]+ cation of 10·0.5PhMe with those of
[Eu2A 2A
(Odpp)4]·PhMe[11] and [Sr (Odpp)4]·PhMe,[17] respective-
ly. This suggests that although the gross features of the [Eu2-
2A 2A
N
15·PhMe (Figure 5) revealed a heterodinuclear complex
N
with two aryloxide ligands bridging the Ca2+ and Eu2+
C
CHTUNGTRENNUNG
ACHTUNGTRENNUNG CHTUNGTRENNUNG CHTNUTRGENNUG
(Odpp)3]+, [Sr (Odpp)3]+ and [Ba (Odpp)3]+ cations appear
to be similar, the larger ionic radius of Ba2+ compared with
Eu2+ and Sr2+ gives rise to structural differences.
In the [Ba2ACHTUNGTRENNUNG
(Odpp)3]+ cations of 12, there are h3-Ph–Ba,
h4-Ph–Ba and h6-Ph–Ba interactions at Ba1, whereas at Ba2
there are h4-Ph–Ba, h2-Ph–Ba and h3-Ph–Ba interactions.
ꢀ
The Ba C lengths (3.137(4)–3.446(4) ꢁ) are in agreement
ꢀ
with the Ba C bond lengths in [Ba
2A
3.449(4) ꢁ).[17] The slightly different p-Ph–Ba interactions
evident in the [Ba2ACTHNUTRGNEUNG
(Odpp)3]+ cations of 12·PhMe,
Figure 5. Structure of [CaEuACHTUNTRGNEUNG(Odpp)4]·PhMe (15·PhMe). Hydrogen atoms
and toluene molecule of solvation are omitted for clarity.
12·4PhMe, 13 and 14 (Table 4) may be rationalised by dif-
ferences in orientation of the phenyl substituents, which are
possibly induced by solvation or the differences in the coun-
terions. Due to the absence of terminal ligands, the [Ba2-
metal atoms and a terminal aryloxide ligand on each. Both
metals are three (oxygen) coordinate. The basic metal–
oxygen framework of 15·PhMe resembles the structure of
ACHTUNGTRENNUNG
(Odpp)3]+ cations display more extensive p-Ph–Ba interac-
tions than [Ba
Ba2).[17] Furthermore, the p-Ph–Ba interactions in the [Ba2-
(Odpp)3]+ cations are more extensive than in the analogous
2ACHTUNGTRENNUNG
(Odpp)4] (h1:h1:h2 at Ba1 and h3:h6:h2 at
[Ca
comparable unit cell dimensions of the two structures. Note
that the [Ca2A(Odpp)4]·PhMe structural motif of the smaller
metal is adopted, rather than that of [Eu2AHCTUNGTERGNUN(N Odpp)4]·PhMe,
(Odpp)4]·PhMe,[17] an observation supported by the
2ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
[M
G
CHTUNGTRENNUNG
the larger size of Ba2+
The Sm O lengths in the [Sm
which has three bridging aryloxide ligands.[11] The metal po-
sitions in 15·PhMe are disordered (Eu1: Eu/Ca 55:45; Ca2:
Ca/Eu 70:30), giving a slight excess of Ca (Ca/Eu 1.14:0.86),
range from 2.149(3) to 2.196(3) ꢁ with an average of 2.17 ꢁ.
After adjusting for the differences in the ionic radii of the
four-coordinate Ln3+ ion,[16] the Sm O bond lengths in the
and this may dictate adoption of the [Ca2ACHTNGUTERNU(NG Odpp)4] frame-
work. X-ray data were collected on several crystals and all
were similarly disordered.
ꢀ
ꢀ
anion of 12·PhMe are in good agreement with the Yb O
bond lengths in the anion of 1·PhMe (2.053(6)–
2.094(7) ꢁ),[11] as are the Yb O bond lengths in 13
The Eu O
G
ꢀ
ꢀ
(2.052(2)–2.071(2) ꢁ). There are very few tetra-coordinated
magnesium alkoxides or aryloxides that can be compared to
and 2.491(3) ꢁ (average 2.43 ꢁ), whereas the Eu O bond
length for the terminal ligand is 2.303(3) ꢁ (Table 3). In the
structure of [Eu
AHCTUNGTREG(NNNU bridging) bond length is longer (2.48 ꢁ), as is the terminal
the [Mg
tral with two aryloxide moieties and either two neutral
donor ligands, as in [Mg(Odpp)2A (Et2O)2-
(thf)2],[25] [Mg
(Odpp)2],[25] and [Mg(OAr3) (thf)2] (OAr3 =2,6-di-tert-butyl-
2A
A
N
ꢀ
A
E
U
Eu O bond (2.361(3) ꢁ), due to the presence of three
ꢀ
A
E
N
bridging ligands rather than two in 15·PhMe. The Ca O-
5512
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Chem. Eur. J. 2009, 15, 5503 – 5519

Rare Earth–Rare Earth and Alkaline Earth–Rare Earth Complexes
FULL PAPER
ꢀ
G
the Sr O (terminal aryloxide) bond length in [Sr2-
(Odpp)4]·PhMe (2.355(2) ꢁ).[17]
The coordination spheres of atoms Sr1 and Eu1 in 16 are
2.30(1) ꢁ) are comparable with those of [Ca
E
ACHTUNGTRENNUNG
(2.275(2), 2.249(2) ꢁ).[17] Likewise, the Ca O bond lengths
for the terminal ligands (2.118(9) vs. 2.122(2) ꢁ) are similar,
as are the O-Ca-O angles for the bridging aryloxide ligands
(75.5(3) vs. 75.3(1)8).
ꢀ
supplemented by p-Ph–metal interactions from pendant
phenyl groups (Table 5). There is an h2-Ph interaction and
3
ꢀ
two h -Ph interactions for Eu1 (Eu C 3.035(9)–3.236(9) ꢁ).
For Sr1, there are two h -Ph interactions (Sr C 3.156(6),
3.293(8) ꢁ). The p-Ph–metal interactions in 16 resemble
those of the relevant atoms of [Sr
1
ꢀ
The voids in the metal coordination spheres owing to the
distorted trigonal-pyramidal geometry around the Ca2+ and
Eu2+ ions in 15·PhMe are occupied by pendant phenyl
groups, resulting in p-Ph–metal interactions that provide co-
ordinative saturation. Eu1 has h2-Ph and h3-Ph interactions
(Odpp)4]·PhMe[17] and
2ACHTUNGTRENNUNG
[Eu2A
CTHUNGTRENNUNG
ꢀ
(Eu C 2.839(4)–3.168(4) ꢁ), whereas Ca1 has h -Ph and h -
Ph interactions (Ca C 2.85(1)–3.17(1) ꢁ; Table 5). As in the
The structures of [BaSr
ACHUTGTNERN(NGU Odpp)4] (17) and [BaEuACHTUNGTRENNUNG(Odpp)4]
ꢀ
(18): As a consequence of the comparable ionic radii of
[16]
structure of [Ca
(Odpp)4]·PhMe,[17] only one bridging arylox-
Sr2+ and Eu2+
and [BaEu(Odpp)4] 18 are very similar, as exemplified by
their comparable unit cell parameters (Table S1 in the Sup-
porting Information). The structure of [BaEu(Odpp)4]
,
the crystal structures of [BaSrACTHNGURETNNU(G Odpp)4] 17
ide ligand contributes to the p-Ph–metal interactions. The h1
contact involves the terminal Odpp ligand. For Eu1, the p-
Ph–Eu interactions differ from those of the Eu atoms of
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
3
3
3
1
1
1
[Eu
(Odpp)4]·PhMe[11] (h :h :h or h :h :h ; Eu C 2.987(4)–
18·PhMe is comparable to that of 18, but with the addition
of a toluene molecule in the crystal lattice and slight differ-
ences in the p-Ph–metal interactions (Table 5). The structur-
al frameworks of 17 and 18, which has a terminal Odpp
bound to barium (Figure 6), are comparable to those of 16
3.240(4) ꢁ), reflecting the differences in the coordination
environments. However, for Ca1 in 15·PhMe the h6-Ph and
h1-Ph interactions resemble the p-Ph–Ca interactions of Ca2
in [Ca
actions and in the Ca C lengths (2.862(2)–3.158(3) ꢁ).
2ACHTUNGTRENNUNG
(Odpp)4]·PhMe,[17] both in the hapticity of the inter-
ꢀ
and the parent homometallic dimeric compounds [M
2ACHTUNGTRENNUNG(m-
Odpp)3A
CTHUNGTRENNUNG
The structure of [SrEu
G
ing aryloxide ligands.
16·PhMe display an unsymmetrical dinuclear structure with
three aryloxide ligands bridging Sr2+ and Eu2+ and a termi-
nal aryloxide ligand bound to Sr1. Because of common
structural features, only the structure of 16 (similar to that
of 18 in Figure 6) is discussed in detail. The difference be-
tween the structural frameworks of 16 and 15·PhMe is a
consequence of the similarity between the ionic radii of Sr2+
and Eu2+ because the structures of both [Sr2-
A
(Odpp)4]·PhMe[11] have the con-
(m-OR)3M’(OR)]
2A(dme)3A
(OAr5)4]
(Odpp)4}]
AHCTUNGTRENNUNG
C
CHTUNGTRENNUNG
AHCTUNGTRENNUNG
(M=Na, K).[26–28] As with 15·PhMe, the metal positions in
16 are disordered (Sr1: Sr/Eu 82:18; Eu1: Eu/Sr 64:36).
Therefore, the overall structure of 16 has an excess of Sr
over Eu (1.18:0.82). A similar, but less marked Sr/Eu disor-
der exists in the structure of 16·PhMe.
Figure 6. Structure of [BaEu
for clarity.
ACHTUNGTERNN(UNG Odpp)4] (18). Hydrogen atoms are omitted
ꢀ
The Ba O
G
ꢀ
The Eu O bond lengths in 16 range from 2.417(7) to
(2.552(4)–2.917(4) ꢁ in 17; 2.562(2)–2.940(2) ꢁ in 18), simi-
ꢀ
2.444(9) ꢁ (average 2.43 ꢁ) and are within the range of the
larly to the Ba O
G
2A
Eu O
G
0.381 ꢁ).[17] This considerable asymmetry in the Ba O-
ꢀ
ꢀ
also agree well with the average Eu O length (2.44 ꢁ) in
ACHTUNGTREN(NUGN bridging) bond lengths correlates with a wide range of Sr/
Eu-O-Ba angles (Table S2 in the Supporting Information).
The largest Sr/Eu-O-Ba angle (98.0(1)8 in 17; 96.95(6)8 in
18) involves the shortest Ba O
the [Eu
(bridging) length (2.44 ꢁ) of Eu2 in [Eu
which also contains three bridging Odpp ligands. The Sr O-
(bridging) bond lengths (2.404(7)–2.622(8) ꢁ) of 16 (average
G
ꢀ
N
A
whereas the smallest angle (91.2(1)8 in 17; 91.19(6)8 in 18)
ꢀ
2.51 ꢁ) are longer than in [Sr
G
involves the longest Ba O
G
2.46 ꢁ),[17] possibly due to the higher coordination number
prisingly, the terminal Ba O bond length (2.458(4) ꢁ in 17;
2.480(2) ꢁ in 18) is in good agreement with that in [Ba2-
ꢀ
(average 4 vs. 3.5). Although the average Sr O
bond length is longer than in 10·0.5PhMe (2.45 ꢁ for
cation 1), the O-Sr-O angles are similar. The Sr O (terminal
aryloxide) bond length in 16 (2.313(8) ꢁ) is comparable to
(Odpp)4] (2.488(2) ꢁ).[17] These are longer than the terminal
ACHTUNGTRENNUNG
lengths in the five-coordinate compounds, [Ba
(thf)3][33] (2.38(1) ꢁ and 2.42(1) ꢁ) and [Ba
2A(m-OCPh3)3-
(OCPh3)
(thf)3][34] (2.409(4) ꢁ), therefore, the p bonding (see
E
A
ACHTUNGTRENNUNG
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www.chemeurj.org
5513

G. B. Deacon, P. C. Junk, K. Ruhlandt-Senge et al.
below) increases the coordination number effectively as well
as formally. Contrasting with the significant range of the
atom is best described as distorted tetrahedral. In addition
to the s coordination of the aryloxide and thf ligands, the
coordination spheres of the Ca2+ atoms are supplemented
by p-Ph–Ca interactions, that is, there are h1-Ph and h2-Ph
interactions at each Ca2+ metal atom. Aside from the pres-
ence of ligated thf in 19, the aryloxo structural frameworks
ꢀ
ꢀ
ꢀ
Ba O
ACHTUNGTRENNUNG
ꢀ
(2.391(4)–2.505(4) ꢁ) and Eu O bond lengths in 18
(2.384(2)–2.489(2) ꢁ) span a narrower range and agree with
the bridging lengths of the three-oxygen-coordinate Sr atom
in [Sr
(Odpp)4]·PhMe[17] (average 2.44 ꢁ) and the three-
of 19 and [Ca2ACTHNGUTERNNUG
(Odpp)4]·PhMe[17] are similar, but the Ca O
aryloxide bond lengths and the p-Ph–Ca interactions differ.
oxygen-coordinate Eu atom in [Eu
(Odpp)4]·PhMe[11] (aver-
ꢀ
ꢀ
age 2.44 ꢁ). The bridging Eu O bond lengths in 18 are
The Ca Odpp bond lengths in 19 range from 2.236(1) to
2.366(1) ꢁ (average 2.30 ꢁ) for the bridging aryloxide li-
slightly shorter than in the heteroleptic complex [Eu
N
(OAr5)4][32] (2.477(6)–2.597(5) ꢁ), in which Eu has a coordi-
gands, whereas the Ca Odpp bond lengths for the terminal
aryloxide ligands are shorter (2.153(1) ꢁ). These bond
ꢀ
nation number of six.
Commensurate with the comparable ionic radii of Sr2+
and Eu2+[16] and the similar unit cell parameters of 17 and
18, the p-Ph–metal interactions in 17 and 18 are similar
(Table 5). Thus, there are h3-Ph–Sr/Eu and h5-Ph–Sr/Eu in-
lengths are longer than the Ca O bond lengths of [Ca2-
ꢀ
(Odpp)4]·PhMe;[17] (Ca O bridging 2.249(2)–2.275(2) ꢁ,
ꢀ
ꢀ
average 2.26 ꢁ; average Ca O terminal 2.12 ꢁ) owing to
the higher (oxygen ligand) coordination number. In contrast
to [Ca2ACTHNGUTERNNUG
(Odpp)4]·PhMe,[17] 19 has more unsymmetrical Odpp
ꢀ
teractions involving Sr1 in 17 and Eu1 in 18. The Sr C
ꢀ
lengths in 17 (3.003(6)–3.285(6) ꢁ) are close to the Eu C
bridging. The Ca···C lengths for the p-Ph–Ca interactions in
19 range from 3.004(1) to 3.119(1) ꢁ and are within the
bond lengths in 18 (3.010(3)–3.292(3) ꢁ). There is an h2-Ph–
1
ꢀ
Ba and two h -Ph–Ba interactions at Ba1 in 17 and 18 (Ba
C 3.199(3)–3.388(6) ꢁ) of enough significance to lengthen
the terminal Ba O bond length beyond that in the five-co-
limits for p-Ph–Ca interactions in [Ca2ACHTNGUTERNU(NG Odpp)4]·PhMe
(3.115(3) ꢁ).[17] The additional steric crowding around the
Ca2+ metal atoms in 19 compared with [Ca2-
ꢀ
ordinate Ba aryloxide (see above). As in the structures of
(Odpp)4]·PhMe[17] is exemplified by the absence of p-Ph–Ca
ACHTUNGTRENNUNG
[Sr
(Odpp)4]·PhMe,[11] the Ph groups of the terminal Odpp
ligand do not participate in p bonding.
2A
[Ba
(Odpp)4][17]
and
[Eu2-
interactions from the terminal Odpp ligands, whereas the
less crowded, lower (oxygen) coordinate metal environment
of [Ca2ACTHNUGTRNE(UNG Odpp)4]·PhMe induces such p-Ph–Ca interactions.
ACHTUNGTRENNUNG
Homometallic structures: Four homometallic complexes,
products of either donor-solvent-induced dissociation or
competing reactions in the synthesis of bimetallic complexes,
were characterised by X-ray crystallography.
The structures of [Tm
The structures of [Tm(Odpp)3] 20 (Figure S1 in the Support-
ing Information) and [Sm(Odpp)3] 21 both crystallise in the
triclinic space group P1 and share similar structural features
with [Ln(Odpp)3] (Ln=Sc, La, Ce, Pr, Nd, Gd, Ho, Er, Yb,
ACHUTGTNERN(NGU Odpp)3] (20) and [SmACHTUNGTRNEN(UGN Odpp)3] (21):
AHCTUNGTRENNUNG
AHCTUNGTRENNUNG
¯
AHCTUNGTRENNUNG
The structure of [Ca
(Odpp)
N
Lu, Y).[29,35–37] The Ln3+ metal atom (Tm3+ in 20 and Sm3+
in 21) is bound to three aryloxide ligands and displays trigo-
nal-planar coordination geometry. In addition to the s coor-
dination of the aryloxide ligands, the coordination sphere of
the Ln3+ metal atom is completed by p-Ph–Ln interactions
with the pendant phenyl arms of the aryloxide ligands,
which cap the Ln3+ metal atom above and below the LnO3
trigonal plane.
[Ca2A(Odpp)4A(thf)2] 19 (Figure 7) crystallised in the mono-
C
CHTUNGTRENNUNG
clinic space group C2/c; half of the molecule resides in the
asymmetric unit. Each Ca2+ metal atom is bound by two
bridging aryloxide ligands, a terminal aryloxide ligand and a
thf ligand. The coordination geometry around each Ca2+
ꢀ
The Tm O bond lengths in 20 range from 2.045(1) to
ꢀ
2.115(1) ꢁ (average 2.08 ꢁ) and the Sm O bond lengths in
21 range from 2.129(2) to 2.186(2) ꢁ (average 2.16 ꢁ).
After subtracting the relevant ionic radii,[16] the average
values (1.20 ꢁ in 20 and 1.20 ꢁ in 21) are comparable to the
ꢀ
average Ln O subtraction bond lengths in [LnACHTUNGTRENNUNG(Odpp)3]
(Ln=Nd (1.19 ꢁ),[37] Yb (1.20 ꢁ)[29] and Lu (1.19 ꢁ)).[36] In
20 and 21 there are h1-Ph and h6-Ph interactions with Ln1,
which is comparable to the p-Ph–Ln interactions observed
in [LnACTHNUTRGENUG(N Odpp)3] (Ln=Ce, Pr, Nd, Gd, Ho, Er, Yb, Lu,
Y).[29,35–37] The Ln C lengths for the p-Ph–Ln interactions in
20 and 21 (2.786(2)–3.051(2) ꢁ and 2.901(2)–3.102(2) ꢁ, re-
ꢀ
Figure 7. Structure of [Ca
ted for clarity. Selected bond lengths [ꢁ] and angles [8]: Ca1 O1
2ACHTUTNGRENNUG(Odpp)4ACHTUGNTRNEN(UGN thf)2] (19). Hydrogen atoms are omit-
ꢀ
ꢀ
spectively) are comparable with analogous Ln C lengths in
ꢀ
ꢀ
ꢀ
2.153(1), Ca1 O2 2.236(1), Ca1 O3 2.332(1), Ca1 O2’ 2.367(1),
Ca1···C262 3.119(1), Ca1···C21’ 3.104(1), Ca1···C212’ 3.004(1), O1-Ca1-O2
117.90(3), O1-Ca1-O3 103.07(3), O2-Ca1-O3 116.40(3), O1-Ca1-O2’
156.82(3), O2-Ca1-O2’ 75.25(3), O3-Ca1-O2’ 85.58(3). Symmetry trans-
[Ln
U
adjustment for ionic radii differences. As seen with the
other members of the [Ln(Odpp)3] series, the presence of p-
Ph–metal interactions results in elongation of the Ln O
AHCTUNGTRENNUNG
formation used to generate equivalent atoms: ’=x+1, y, ꢀz+1= .
ꢀ
2
5514
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Chem. Eur. J. 2009, 15, 5503 – 5519

Rare Earth–Rare Earth and Alkaline Earth–Rare Earth Complexes
FULL PAPER
bonds of the aryloxide ligands involved in p-Ph–metal inter-
ed charge-separated species [Ba
A dinuclear neutral species [AeEu
when Eu metal and Ca, Sr or Ba metal were reacted with
HOdpp, and [BaSr(Odpp)4] was prepared similarly. As a
result of the absence of donor-solvent co-ligands, the struc-
tures of the complex cations [(Ln’/Ae)2A
(Odpp)3]+ and neu-
G
ACHUTGTNRNE(NUG Odpp)3ACHTUNGTRENNUNG(thf)].
ꢀ
actions to give the relatively large range of Ln O bond
lengths.
AHCTUNGTRENNUNG
The structure of [Sr
[Sr(Odpp)2A(thf)3] 22 (Figure S2 in the Supporting Informa-
(thf)3] (22): The Sr2+ atom of
ACHUTGTNRNENUG(Odpp)2ACHTUNGTRENNUGN
A
U
tion) is bound by two Odpp ligands and three thf ligands,
and adopts a distorted trigonal-bipyramidal coordination ge-
ometry. Two Odpp ligands reside in the axial positions (O-
tral heterobimetallics feature extensive p-Ph–metal interac-
tions with the pendant phenyl groups of the Odpp ligands,
which enables the large electropositive metal atoms to
attain coordination saturation and steric protection. These
results reveal the utility and generality of this metal-based
A
ACHTUNGTRENNUNG
A
ACHTUNGTRENNUNG
synthetic route for the synthesis of heterobiACHTNUTRGNEmNUG etallic com-
A
R
plexes and establish a new class of charge-separated com-
plexes.
A
CHTUNGTRENNUNG
ACHTUNGTRENNUNG
Experimental Section
a thf ligand in the equatorial positions. This is an unexpect-
ed stereochemical consequence of the lower crowding in 22
(ꢀ steric coordination numbers 7.2 and 8.4, respective-
ꢀ
The compounds described herein are extremely air and moisture sensi-
tive and consequently all manipulations were carried out by using stan-
dard Schlenk line and drybox techniques under an atmosphere of puri-
fied nitrogen. Solvents were dried, purified and de-oxygenated by using
standard procedures. 2,6-diphenylphenol (HOdpp) and 1,2,4,5-tetrame-
thylbenzene (Aldrich) were used as received. 1,3,5-tri-tert-butylbenzene
was obtained from Aldrich (Compounds 3–7, 10, 11, 15, 16), or prepared
ly).[38b,c] The Sr O
ACTHNUTRGNE(NUG Odpp) lengths in 22 (2.305(3),
2.307(3) ꢁ) are comparable to those in [SrACHTNUTRGENNUG 2ACHTUNGTRENNUGN
(OAr6) (thf)3][38a]
(2.32(1), 2.31(1) ꢁ), despite the differences in ligand ar-
rangement. The Sr O
(2.471(3)–2.602(3) ꢁ) compared with the corresponding
lengths in [Sr
ꢀ
(thf) lengths fall over a wide range
according to
(Odpp)4]·PhMe,[17] [Ba
(thf)2][25] were prepared according to literature procedures, but without
activation by mercury for [Ba2A(Odpp)4]. Rare earth metals were obtained
a
literature procedure[40] (12, 13, 17, 18, 22). [Ca2-
2A (Odpp)2-
(Odpp)4],[17] [Nd(Odpp)3][36] and [Mg
N
C
R
ACHTUNGTRENNUNG
(OAr6)
R
AHCTUNGTRENNUNG
the aggregate [Sr
C
E
CHTUNGTRENNUNG
CTHUNGTRENNUNG
2.584(8) ꢁ). The Sr-O-C1,19 angles in 22 are slightly bent
(157.6(3), 168.7(3)8), possibly to minimise steric repulsion
and to allow close approach of one phenyl ring to Sr1. This
as powders from Rhone Poulenc or were freshly filed from chunks (San-
toku), and alkaline earth metal turnings or chunks (Aldrich) were simi-
larly treated. Melting points were measured in pipettes sealed under ni-
trogen, and are uncalibrated. 1H NMR spectra were recorded by using a
Bruker DPX 300 spectrometer and the chemical shifts are referenced to
the residual resonances of the solvent. IR spectra (4000–650 cmꢀ1) were
recorded as Nujol mulls sandwiched between NaCl plates by using a
Perkin–Elmer 1600 FTIR spectrometer (2–11, 15, 16, 19), or as Nujol
mulls sandwiched between KBr plates using a Nicolet IR200 spectrome-
ter (12–14, 17, 18, 22). Microanalyses were performed in duplicate by the
Campbell Microanalytical Laboratory, University of Otago, Dunedin,
New Zealand (2–11, 15, 16, 19) or by Complete Analysis Laboratory,
Inc., Pasippany, NJ, USA (12–14, 17, 18; including barium). The neody-
mium analysis (6) was performed by using EDTA titration with a Xyle-
nol Orange indicator[41] following the digestion of an accurately weighed
sample in concentrated nitric and sulfuric acids and buffering with hexa-
phenyl ring sits across the wide O3-Sr-O5 angle (139.4(1)8)
1
ꢀ
and provides an h -p-Ph–Sr interaction. The Sr C length
ꢀ
ꢀ
(Sr C(12) 3.275(4) ꢁ) is in agreement with Sr C lengths for
p-Ph–Sr interactions in [Sr2ACTHNUTRGNEUNG
(Odpp)3]+ cations discussed pre-
viously.
Conclusion
The direct reaction of a rare earth metal (Ln) and either a
potential divalent rare earth metal (Ln’) or an alkaline earth
metal (Ae) with HOdpp at elevated temperature gave ho-
moleptic heterobimetallic complexes. The charge-separated
AHCTUNGTRENNUNG
2ACHTUNGTRENN(UNG Odpp)3][Ln-
AHCTUNGTRENNUNG
um or barium metal and 2,6-diphenylphenol, usually with a flux (1,3,5-
tri-tert-butylbenzene or 1,2,4,5-tetramethylbenzene) and Hg (2 drops)
were sealed under vacuum in a thick-walled Carius tube and then heated
under the conditions indicated below. After reaction, the tubes were
cooled and opened in the dry-box. In general, the products were either
extracted with and recrystallised from toluene at 1908C (for procedure,
see below) or, in the case of reactions with barium metal, the products
were extracted and recrystallised from toluene/thf. In cases where the
sole characterisation was X-ray crystallography of hand-picked single
crystals, preparative details are in the Supporting Information (com-
pounds 1, 4, 5, 8, 9).
[(Ln’/Ae)2ACHTUNGTRENNUNG(Odpp)3][LnCAHTUNGTRNEN(UGN Odpp)4] structural class was ob-
tained for a range of metal atoms (Ln’=Yb, Eu; Ae=Ca,
Sr, Ba; Ln=Nd, Sm, Ho, Y, Tm, Yb) and the structures
demonstrate the similarities between the chemistry of the al-
kaline earth metals and divalent rare earth metals, with
triply Odpp-bridged [(Ln’/Ae)
structures and low-coordinate [LnAHCUTNGTRENNUNG
(Odpp)3]+ cations in all
(Odpp)4]ꢀ anions. The het-
erobimetallic complexes with Ln’ or Ae=Ca, Sr are frag-
mented into homometallic species in thf and are insoluble in
non-polar solvents. To overcome this issue, the heterobime-
tallic complexes were extracted with toluene under pressure
at 1908C. In contrast, the complexes with Ae=Ba were suc-
cessfully recrystallised from toluene/thf. Treatment of [Ba2-
General procedure for the crystallisation of charge-separated heterobi-
metallic complexes from toluene at 1908C: The reaction mixture (consist-
ing of the heterobimetallic complex, unreacted metal and homometallic
co-products) was first washed with hexane (50 mL) to remove 1,3,5-tri-
tert-butylbenzene, then with toluene (50 mL) to remove homometallic
co-products. The resulting solid was dried under vacuum, placed in a
ACHTUNGTRENNUNG(Odpp)4] with [MgACHTUNGTRENNUNG(Odpp)2ACHTGUNTREN(NUGN thf)2] in toluene afforded a relat-
Chem. Eur. J. 2009, 15, 5503 – 5519
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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5515

G. B. Deacon, P. C. Junk, K. Ruhlandt-Senge et al.
Carius tube and covered with a plug of glass wool. Toluene (15 mL) was
added to the tube, which was subsequently cooled in liquid N2, evacuated
and sealed. The tube was then heated at 1908C for 24 h; the vapour pres-
sure exerted by toluene is approximately 7 atm at this temperature.
Under these forcing conditions, the heterobimetallic complex was solu-
ble; the tube was carefully inverted while hot so that filtration occurred
through the glass wool plug. The tube was then returned to the oven and
progressively cooled to ambient temperatures (108C per day) to afford
crystalline materials of the heterobimetallic complexes, often as single
crystals of toluene solvates. The Carius tube was opened in the drybox
and the crystalline material transferred to a Schlenk flask and dried
under vacuum.
was noted. Dark-green crystals of 6·PhMe, suitable for single-crystal X-
ray analysis, were deposited amongst the light blue crystals.
Method 2: Similarly to the synthesis of 3, Ca metal (0.05 g, 1.2 mmol), Nd
metal (0.10 g, 0.7 mmol), HOdpp (1.15 g, 4.7 mmol), 1,3,5-tri-tert-butyl-
benzene (0.5 g, 2.0 mmol) and Hg (2 drops) were heated at 2108C under
vacuum for 5 d to give a light blue crystalline material from which the
1,3,5-tri-tert-butylbenzene was sublimed to the end of the tube. After ex-
traction with toluene (50 mL) at RT, the reaction mixture was recrystal-
lised from toluene at 1908C to give blue microcrystals of 6·PhMe (not of
X-ray quality), which were dried under vacuum (yield 0.62 g, 48%). M.p.
245–2488C; 1H NMR (200 MHz, [D8]thf, 258C): d=12.27* (brs, 6H; m-
HArO), 10.23* (brs, 15H; o-H(Ph)+p-HArO), 7.56 (d, 16H; o-H(Ph)),
ꢀ
7.24 (brs, 21H; m-H(Ph)+HAr PhMe), 7.06 (brd, 16H; p-H(Ph)+m-
HArO), 6.42 (brs, 4H; p-HArO), 4.03* (brs, 12H; m-H(Ph)), 3.80*, (brs,
Caution! H2 gas is generated during the direct metalation reactions em-
ployed in this work. Accordingly, reaction scales must be adjusted to
avoid exceeding a pressure of 15 atm when using heavy-walled Carius
tubes. Furthermore, when recrystallising the bimetallic complexes from
toluene in heavy-walled Carius tubes, the vapour pressure of toluene
must not exceed 15 atm and the temperature of the oven should be moni-
tored. Safety precautions, such as using a metal sleeve, must be applied
when heating and handling Carius tubes.
6H; p-H(Ph)), 2.36 ppm (brs, 3H; CH3 PhMe) (* denotes NdIII); IR
ꢀ
(Nujol): n˜ =1596 m, 1578 m, 1495 m, 1406 s, 1309 m, 1286 s, 1269 s, 1250
m, 1176 w, 1156 w, 1110 w, 1084 m, 1070 m, 1026 w, 1010 w, 994 w, 914 w,
859 s, 800 w, 767 m, 753 s, 729 m, 702 s, 601 cmꢀ1 s; elemental analysis
calcd (%) for C126H91Ca2Nd1O7 (1941.49; toluene of solvation lost): C
77.95, H 4.72, Nd 7.43; found: C 78.18, H 4.99, Nd 7.58.
The 1H NMR spectrum of 6·PhMe is a composite (1:1) of the spectra of
[Ca2ACHTUNTRGENNUG(Odpp)4]·PhMe and [NdACHTUTGNREN(NUNG Odpp)3], as observed for freshly prepared
Synthesis of charge-separated complexes [(Ln’/Ae)
[Yb2A(Odpp)3][Y(Odpp)4] (2)
Method 1: Yb metal (0.17 g, 1.0 mmol),
2ACHTUNGTRNENUG(Odpp)3][LnACHTUNTGNER(NUGN Odpp)4]
A
N
ACHTUNGTRENNUNG
solutions of these compounds in [D8]thf, as follows: [Ca2ACHTNUGRTENUNG(Odpp)4]·PhMe
1H NMR (200 MHz, [D8]thf, 258C): d=7.40 (d, J=7.3 Hz, 16H; o-
Y
metal (0.35 g, 4.0 mmol),
HOdpp (0.98 g, 4.0 mmol) and Hg (2 drops) were heated at 2208C under
vacuum for 5 d. Treatment of the near-insoluble tube contents with tolu-
ene (120 mL) at RT gave an orange solution. Filtration, slight evapora-
tion and standing for several days gave a few orange crystals of 2·2PhMe
suitable for X-ray crystallography. The dried insoluble material was re-
crystallised from toluene at 1908C to afford X-ray-quality orange crystals
ꢀ
H(Ph)), 7.06 (overlap, t, J=7.3 Hz, 21H; m-H(Ph)+HAr PhMe), 6.90
(overlap, d, J=7.3 Hz, 16H; p-H(Ph)+m-HArO), 6.30 (t, J=7.3 Hz,
ꢀ
4H; p-HArO), 2.18 ppm (s, 3H; CH3 PhMe); [Nd
(Odpp)3] 1H NMR
(200 MHz, [D8]thf, 258C): d=12.26 (d, J=7.3 Hz, 6H; m-HArO), 10.23
(brm, 15H; o-H(Ph)+p-HArO), 4.06 (brs, 12H; m-H(Ph)), 3.82 ppm
(brs, 6H; p-H(Ph)).
¯
of 2·0.5PhMe (yield 0.65 g, 59%). (Unit cell: P1; a=16.7025(5), b=
Preparative-scale treatment of 6·PhMe with thf: A bulk sample of 6·PhMe
from method 2 was extracted with thf (50 mL) to give a bright blue solu-
tion. Concentration of the solution to about 20 mL and storage at ꢀ108C
for several days gave a mixture of blue and colourless crystals. The
23.4531(7), c=25.0191(8) ꢁ; a=98.056(2), b=92.065(2), g=90.447(2)8;
ACTHNUTRGNEUNG
V=9696.8(5) ꢁ3). The metal positions of the [Y(Odpp)4]ꢀ anions were
disordered Y3+/Yb3+ approximately 70:30. IR (Nujol): n˜ =1596 m, 1580
m, 1564 m, 1495 m, 1410 s, 1307 m, 1288 s, 1269 s, 1176 w, 1158 w, 1109 w,
1070 m, 1026 m, 1011 m, 995 w, 929 w, 915 w, 867 m, 852 m, 800 w, 749 s,
730 w, 704 s, 626 cmꢀ1 m; elemental analysis calcd (%) for
¯
former were identified as [NdACTHGNURTNE(UNNG Odpp)3AHCUTNERGN(NUG thf)2]·2thf (Unit cell: P1; a=
10.1112, b=21.624, c=13.2075 ꢁ; a=90, b=100.046, g=908, in agree-
ment with reported data),[37] but the colourless crystals were unsuitable
for single crystal X-ray analysis.
C
129.5H95O7Y1Yb2 (2198.15): C 70.76, H 4.36; for C129.5H95O7Y0.7Yb2.3
(2223.39; assuming disorder in single crystals applies to the bulk sample):
C 69.96, H 4.31; found: C 70.88, H 4.56.
Preparative-scale treatment of 6·PhMe with toluene/thf: A sample of
6·PhMe was suspended in toluene (50 mL) and thf (8 mL) was added
dropwise to the reaction mixture with constant stirring to give a blue so-
lution. The solution was filtered and the volume reduced to about 40 mL,
Method 2: After a similar synthesis, a small quantity of the reaction mix-
ture was recrystallised from toluene (3 mL) at 1908C by using a small
thick-walled glass tube to afford a few orange crystals of 2·1.5PhMe.
which gave colourless crystals of [Ca2ACHTNUTRGENNUG(Odpp)4ACHTUNGTERNN(UGN thf)2] 19 suitable for X-ray
¯
crystallography after several days (yield 0.46 g, 38%). 1H NMR
(300 MHz, [D6]benzene, 258C): d=7.78 (d, J=7.2 Hz, 16H; o-H(Ph)),
7.59–7.55 (m, 8H; m-HArO), 7.32 (t, 16H; m-H(Ph)), 7.24–7.19 (m,
12H; p-H(Ph)+p-HArO), 2.55 (brs, 8H; OCH2-thf), 1.15 ppm (brs, 8H;
(Unit cell: P1; a=16.339(3), b=16.717(3), c=19.081(4) ꢁ; a=88.88(3),
b=83.68(3), g=89.18(3)8; V=5179(2) ꢁ3.)
ACHTUNGTRENNUNG[Eu2ACHTUNGTRENNUNG(Odpp)3][YACHTUNGTRENNUNG(Odpp)4] (3): Eu metal (0.15 g, 1.0 mmol), Y metal
(0.36 g, 4.0 mmol), HOdpp (1.0 g, 4.0 mmol), 1,3,5-tri-tert-butylbenzene
(0.5 g, 2.0 mmol) and Hg (2 drops) were heated at 2108C for 5 d to give a
yellow crystalline product interspersed with unreacted metal. A crystal of
3 was hand-picked from the reaction mixture. The reaction mixture was
recrystallised from toluene at 1908C to afford bright yellow crystals of
3·0.5PhMe that were suitable for single-crystal X-ray analysis after
drying in vacuo (yield 0.45 g, 43%). IR (Nujol): n˜ =1597 m, 1581 m, 1495
m, 1410 s, 1309 m, 1288 s, 1267 s, 1176 w, 1158 w, 1111 w, 1087 m, 1070 m,
1026 m, 1011 m, 994 w, 916 w, 866 s, 850 s, 800 w, 762 s, 749 s, 729 m, 704
s, 607 cmꢀ1 s; elemental analysis calcd (%) for C129.5H95Eu2O7Y1
(2155.99): C 72.14, H 4.44; found: C 72.08, H 4.58.
ꢀ
CH2 thf); IR (Nujol): n˜ =1596 s, 1578 s, 1567 m, 1556 m, 1495 s, 1410 s,
1311 s, 1298 s, 1279 s, 1256 s, 1184 w, 1172 w, 1154 m, 1104 w, 1086 m,
1071 s, 1036 s, 1010 m, 994 m, 982 w, 958 w, 942 w, 910 m, 892 m, 861 s,
848 m, 802 m, 754 s, 716 s, 701 s, 884 m, 668 w, 620 m, 612 m, 596 cmꢀ1 m;
elemental analysis calcd (%) for C80H68Ca2O6 (1205.50): C 79.70, H 5.69;
found: C 78.63, H 5.51.
AHCTNUGTREN[GUNN Ca2ACHTUNRTGEGN(NNU Odpp)3][HoACHTGUNTREN(UNGN Odpp)4] (7)
Method 1: Similarly to the synthesis of 3, Ca metal (0.04 g, 1.0 mmol), Ho
metal (0.66 g, 4.0 mmol), HOdpp (1.15 g, 4.7 mmol) and Hg (2 drops)
were heated at 2208C for 5 d to afford a yellow crystalline material along
with unreacted metal. After cooling to RT, a yellow crystal of 7 suitable
for X-ray crystallography was hand-picked from the reaction mixture.
The presence of [HoACTHNUTRGNEUNG(Odpp)3] in the reaction mixture was confirmed by
unit cell measurements. (Unit cell: P1; a=10.8713, b=13.0768, c=
15.7451 ꢁ; a=73.9754, b=87.6061, g=67.79178; V=1983.7 ꢁ3, in agree-
ACHTUNGTRENNUNG[Ca2ACHTUNGTRENNUNG(Odpp)3][NdACHTUNGTRENNUNG(Odpp)4] (6)
Method 1: Ca metal (0.13 g, 3.3 mmol), Nd metal (0.94 g, 6.5 mmol),
HOdpp (1.0 g, 4.0 mmol) and Hg (2 drops) were heated at 2108C for 5 d
to give a light blue crystalline material and unreacted metal. The reaction
mixture was extracted with toluene (100 mL) at RT to give a light blue
solution and a blue precipitate. The solution was filtered and concentrat-
ed to about 60 mL, then cooled to ꢀ208C to give light blue crystals of
¯
ment with data for [LuACTHNUTRGNEUNG
(Odpp)3]).[36]
Method 2: The reaction was repeated with Ca metal (0.04 g, 1.1 mmol),
Ho metal (0.10 g, 0.6 mmol), HOdpp (0.98 g, 4.0 mmol), 1,3,5-tri-tert-bu-
tylbenzene (0.50 g, 2.0 mmol) and Hg (2 drops) at 2108C for 5 d. The
yellow crystalline material was recrystallised from toluene at 1908C to
afford yellow crystals of 7, which were dried under vacuum (yield 0.31 g,
¯
[NdACHTUNGTRENNUNG(Odpp)3] (Unit cell: P1; a=10.908, b=13.0256, c=15.5716 ꢁ; a=
76.425, b=87.682, g=67.3758, in agreement with reported values).[37]
When the light blue toluene solution containing crystals of [Nd(Odpp)3]
was stored at ꢀ208C for several weeks, a colour change to dark green
AHCTUNGTRENNUNG
5516
www.chemeurj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 5503 – 5519

Rare Earth–Rare Earth and Alkaline Earth–Rare Earth Complexes
FULL PAPER
28%). M.p. 342–3488C; IR (Nujol): n˜ =1596 m, 1583 m, 1564 m, 1496 s,
1439 s, 1410 s, 1357 m, 1309 m, 1288 s, 1270 s, 1176 w, 1158 w, 1088 m,
1071 m, 1027 m, 1011 m, 995 w, 927 w, 915 w, 865 s, 854 s, 801 m, 773 m,
750 s, 704 s, 672 w, 626 w, 605 cmꢀ1 s; elemental analysis calcd (%) for
gave orange crystals of 14 after 2 d (yield 0.12 g, 23%). IR (Nujol): n˜ =
1584 m, 1496 m, 1403 s, 1321 w, 1286 m, 1222 w, 1164 w, 1070 m, 1030 w,
1000 w, 913 w, 837 s, 808 m, 755 s, 703 s, 604 cmꢀ1 m; barium analysis
calcd (%) for C112H86Ba2MgO7 (toluene of solvation lost, 1842.80): Ba
14.90; found: Ba 14.66.
C
126H91Ca2Ho1O7 (1962.08): C 77.13, H 4.67; found: C 76.99, H 4.61.
A
N
ACHTUNGTRENNUNG
Synthesis of neutral complexes [AeEu
unsuccessful attempt to prepare [CaSr
(thf)3] is discussed in the Supporting Information.
[CaEu(Odpp)4] (15): Ca metal (0.04 g, 1.0 mmol), Eu metal (0.15 g,
N
ACHTUNGTRENNUNG
(0.10 g, 1.1 mmol), Nd metal (0.09 g, 0.6 mmol), HOdpp (0.98 g,
4.0 mmol), 1,3,5-tri-tert-butylbenzene (0.5 g, 2.0 mmol), and Hg (2 drops)
were heated at 2208C under vacuum for 5 d. The resulting blue-coloured
reaction mixture was recrystallised from toluene at 1908C to give blue
crystals of 10·0.5PhMe, which were dried under vacuum (yield 0.41 g,
36%). M.p. >3608C; IR (Nujol): n˜ =1596 m, 1580 m, 1560 m, 1495 m,
1406 s, 1357 w, 1311 m, 1284 s, 1268 s, 1176 w, 1158 w, 1110 w, 1085 m,
1070 m, 1026 m, 1012 m, 994 w, 950 w, 928 w, 916 w, 859 s, 849 s, 800 w,
763 s, 749 s, 730 m, 703 s, 668 w, 626 m, 602 cmꢀ1 s; elemental analysis
calcd (%) for C129.5H95Nd1O7Sr2 (2082.65): C 74.68, H 4.60; found: C
74.77, H 4.69.
G
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
A
ACHTUNGTRENNUNG
1.0 mmol), HOdpp (1.0 g, 4.0 mmol), 1,3,5-tri-tert-butylbenzene (0.5 g,
2.0 mmol) and Hg (2 drops) were heated at 2108C for 5 d to give a
yellow crystalline material, which was washed with hexane (50 mL) and
then extracted with toluene (70 mL) to give a yellow solution. Concentra-
tion to 50 mL and standing for several days afforded yellow crystals of
15·PhMe. The metal positions are disordered approximately 45:55 and
70:30 (Ca/Eu), as observed for several crystals (yield 0.34 g, 27%). M.p.
>3608C; IR (Nujol): n˜ =1596 m, 1581 m, 1564 m, 1496 m, 1408 s, 1309
m, 1289 s, 1268 s, 1177 w, 1157 w, 1085 w, 1070 m, 1027 w, 1012 w, 994 w,
928 w, 916 w, 861 m, 851 m, 801 w, 763 s, 753 s, 727 m, 703 s, 601 cmꢀ1 s;
elemental analysis calcd (%) for C72H52Ca1Eu1O4 (1173.24; toluene of
solvation lost): C 73.71, H 4.47; for C72H52Ca1.14Eu0.86O4 (1249.09; accord-
ing to disordered composition, toluene of solvation lost): C 75.14, H 4.55;
found: C 71.01, H 4.47.
ACHTUNGTRENNUNG[Sr2ACHTUNGTRENNUNG(Odpp)3][HoACHTUNGTRENNUNG(Odpp)4] (11): Sr metal (0.10 g, 1.1 mmol), Ho metal
(0.10 g, 0.61 mmol), HOdpp (0.98 g, 4.0 mmol), 1,3,5-tri-tert-butylbenzene
(0.5 g, 2.0 mmol), and Hg (2 drops) were heated at 2208C under vacuum
for 5 d. Recrystallisation from toluene at 1908C afforded yellow crystals
¯
of 11·0.5PhMe (yield 0.37 g, 32%). A unit cell (P1; a=16.5268, b=
23.5196, c=25.0967 ꢁ; a=82.806, b=89.928, g=89.8338; V=9678.30 ꢁ3)
of a representative crystal established that 11·0.5PhMe is isomorphous
with 10·0.5PhMe. M.p. >3608C; IR (Nujol): n˜ =1597 m, 1582 m, 1561 m,
1495 s, 1410 s, 1357 m, 1308 m, 1286 s, 1270 s, 1176 w, 1158 w, 1111 w,
1080 w, 1070 m, 1026 m, 1012 m, 994 w, 949 w, 926 w, 916 w, 865 s, 850 s,
800 w, 764 s, 749 s, 730 m, 704 s, 627 m, 606 cmꢀ1 s; elemental analysis
calcd (%) for C129.5H95Ho1O7Sr2 (2103.34): C 73.95, H 4.55; found: C
73.74, H 4.65.
ACHUTNERGN[NUG SrEuCAHTUNGTNER(NUGN Odpp)4] (16): Sr metal (0.09 g, 1.0 mmol), Eu metal (0.15 g,
1.0 mmol), HOdpp (1.0 g, 4.0 mmol), 1,3,5-tri-tert-butylbenzene (0.5 g,
2.0 mmol) and Hg (2 drops) were heated at 2108C under vacuum for 5 d
to give a yellow crystalline material and unreacted metal. The 1,3,5-tri-
tert-butylbenzene was sublimed to the end of the tube. A yellow crystal
of 16 was hand-picked from the reaction mixture. The two metal posi-
tions were disordered approximately 80:20 and 35:65 (Sr/Eu). The tube
contents were washed with hexane (50 mL), then extracted in hot toluene
(80 mL) to give a yellow solution. Slow-cooling the toluene to RT gave
yellow crystals of 16·PhMe. The two metal positions (Sr/Eu) were disor-
dered approximately 90:10 and 25:75 (yield 0.30 g, 23%). M.p. 170–
1748C; IR (Nujol): n˜ =1589 m, 1557 m, 1493 m, 1408 s, 1299 m, 1282 s,
1264 m, 1252 m, 1170 w, 1157 w, 1083 w, 1068 m, 1026 w, 1010 w, 992 w,
929 w, 912 w, 849 s, 803 w, 771 w, 759 s, 746 m, 734 m, 709 s, 598 m,
586 cmꢀ1 s; elemental analysis calcd (%) for C79H60Eu1O4Sr1 (1312.92): C
72.27, H 4.61; for C79H60Eu0.87O4Sr1.13 (1304.32; according to the single
crystal composition): C 72.63, H 4.63; found: C 72.53, H 4.85.
ACHTUNGTRENNUNG[Ba2ACHTUNGTRENNUNG(Odpp)3][SmACHTUNGTRENNUNG(Odpp)4] (12)
Method 1: Ba metal (0.14 g, 1.0 mmol), Sm metal (0.15 g, 1.0 mmol),
HOdpp (1.00 g, 4.0 mmol), 1,3,5-tri-tert-butylbenzene (0.5 g, 2.0 mmol)
and Hg (1 drop) were heated at 2358C under vacuum for 7 d to give col-
ourless crystals and a small amount of yellow crystalline material. A col-
ourless crystal of 12 was hand-picked from the reaction mixture, as was a
yellow crystal of [SmACHTUNGTRENNUNG(Odpp)3] 21. Extraction of the reaction mixture with
toluene/thf (10:3; total volume 33 mL) then reduction of the volume in
vacuo to 5 mL gave a green oily solution, which afforded a small number
of green crystals of 12·PhMe suitable for X-ray crystallography on stand-
ing overnight.
ACHUTNERGN[NUG BaSrCAHTUNGTNER(NUGN Odpp)4] (17): Ba metal (0.28 g, 2.0 mmol), Sr metal (0.18 g,
Method 2: Similarly to the synthesis of 12·PhMe, Ba metal (0.20 g,
1.5 mmol), Sm metal (0.22 g, 1.5 mmol), HOdpp (1.75 g, 7.0 mmol), 1,3,5-
tri-tert-butylbenzene (0.5 g, 2.0 mmol) and Hg (1 drop) were heated at
2258C for 7 d. Extraction of the reaction mixture with toluene/thf (6:1;
total volume 35 mL) followed by reduction of the volume in vacuo to
15 mL afforded green crystals of 12·4PhMe after 6 days at ꢀ208C (yield
1.0 g, 46%). M.p. 255–2608C; IR (Nujol): n˜ =1590 m, 1403 m, 1304 w,
1269 m, 1152 w, 1070 w, 1024 w, 1006 w, 983 w, 860 m, 843 m, 744 s, 691 s,
627 cmꢀ1 w; elemental analysis calcd (%) for C126H91Ba2SmO7 (2142.12;
toluene of solvation lost): C 71.08, H 4.38, Ba 12.55; found: C 68.54, H
4.65, Ba 12.02.
2.0 mmol), HOdpp (1.0 g, 4.0 mmol), 1,3,5-tri-tert-butylbenzene (0.5 g,
2.0 mmol) were heated at 2358C under vacuum for 7 d. A crystal of 17
was hand-picked from the reaction mixture. Extraction of the reaction
mixture with toluene/thf (5:1; 25 mL) gave colourless crystals of 17 after
7 d at ꢀ208C (yield 0.26 g, 22%). M.p. 283–2868C; 1H NMR (300 MHz,
[D8]thf, 258C): d=7.65 (s, 16H; o-H(Ph)), 7.24 (t, 16H; m-H(Ph)), 7.07
(t, 8H; m-HArO), 7.00 (d, 8H; p-H(Ph)), 6.36 ppm (brs, 4H; p-HArO);
IR (Nujol): n˜ =1584 w, 1543 w, 1450 s, 1415 m, 1298 w, 1269 w, 1257 w,
1170 w, 1059 w, 1018 w, 1006 w, 837 s, 802 w, 750 m, 575 cmꢀ1 m; barium
analysis calcd (%) for C72H52Ba1Sr1O4 (1206.10): Ba 11.39; found: Ba
11.52.
ACHTUNGTRENNUNG[Ba2ACHTUNGTRENNUNG(Odpp)3][YbACHTUNGTRENNUNG(Odpp)4] (13): Ba metal (0.14 g, 1.0 mmol), Yb metal
ACHUTNRGEN[NUG BaEuACHUTNGTREN(NUGN Odpp)4] (18)
(0.17 g, 1.0 mmol), HOdpp (1.0 g, 4.0 mmol), 1,3,5-tri-tert-butylbenzene
(0.5 g, 2.0 mmol) and Hg (1 drop) were heated at 2358C under vacuum
for 7 d to afford a yellow crystalline material, from which a crystal of 13
was hand-picked. Extraction of the reaction mixture with toluene/thf
(4:5; 45 mL) gave an orange solution from which a yellow crystalline
solid of 13 precipitated (yield 0.73 g, 59%). IR (Nujol): n˜ =1590 m, 1403
s, 1292 m, 1246 m, 1170 w, 1158 w, 1106 w, 1070 w, 1024 w, 1006 w, 873 m,
820 m, 790 m, 744 s, 691 s, 580 cmꢀ1 m; elemental analysis calcd (%) for
C126H91Ba2YbO7 (2164.71): C 69.91, H 4.24, Ba 12.69; found: C 69.71, H
4.13, Ba 12.56.
Method 1: Ba metal (0.14 g, 1.0 mmol), Eu metal (0.15 g, 1.0 mmol),
HOdpp (1.0 g, 4.0 mmol), 1,3,5-tri-tert-butylbenzene (0.5 g, 2.0 mmol) and
Hg (1 drop) were heated at 2358C under vacuum for 7 d. Extraction of
the reaction mixture with toluene/thf (6:1; 35 mL) followed by reduction
of the volume in vacuo to 20 mL afforded orange crystals of 18 after 2 d
at RT (yield 0.74 g, 61%). Barium analysis calcd (%) for C72H52Ba1Eu1O4
(1270.44): Ba 10.81; found: Ba 10.63.
Method 2: Similarly, Ba metal (0.28 g, 2.0 mmol), Eu metal (0.30 g,
2.0 mmol), HOdpp (1.0 g, 4.0 mmol) and 1,3,5-tri-tert-butylbenzene (0.5 g,
2.0 mmol) were heated at 2508C under vacuum for 7 d. Extraction with
toluene/thf (2:1; 30 mL) and cooling to 08C overnight afforded orange
crystals of 18·PhMe (yield 0.55 g, 43%). M.p. 265–2708C; IR (Nujol): n˜ =
1596 m, 1543 w, 1491 m, 1403 s, 1316 m, 1275 s, 1164 w, 1147 w, 1053 m,
1030 w, 1024 w, 983 w, 925 w, 855 s, 796 m, 767 s, 697 s, 575 cmꢀ1 s;
A
2ACHTUNGTRENNUNG(Odpp)3][MgACHTUNGTRENNUNG(Odpp)3ACHTUNTREGGN(NUN thf)] (14): A suspension of [MgAHTCNUGTREN(NUNG Odpp)2ACHTUNTGNUER(GN thf)2]
CHTUNGTRENNUNG
ous mixture was stirred overnight and warmed at 808C to give an
orange-coloured solution, which was then filtered and stored at 08C and
Chem. Eur. J. 2009, 15, 5503 – 5519
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
5517

G. B. Deacon, P. C. Junk, K. Ruhlandt-Senge et al.
barium analysis calcd (%) for C72H52BaEuO4: (1270.49, toluene of solva-
tion lost) Ba 10.81; found: Ba 10.67.
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X-Ray crystallography: Intensity data were collected by using a Bruker
Apex II CCD or an Enraf–Nonius KAPPA CCD with MoKa radiation
(l=0.7170 ꢁ). Suitable crystals were immersed in viscous hydrocarbon
oil and mounted on a glass fibre, which was then mounted on the diffrac-
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Supporting Information. CCDC 713749 (2·2PhMe), 713750 (3), 713751
(3·0.5PhMe), 713752 (4), 713753 (5), 713754 (6·PhMe), 713755 (7),
713756 (9), 713757 (10·0.5PhMe), 713758 (12), 713759 (12·PhMe), 713760
(12·4PhMe), 713761 (13), 713762 (14), 713763 (15·PhMe), 713764 (16),
713765 (16·PhMe), 713766 (17), 713767 (18), and 713768 (18·PhMe) con-
tains the supplementary crystallographic data for this paper. These data
can be obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif. Variata are given
in the Supporting Information.
Acknowledgements
We are grateful to the Australian Research Council for support and to
the Faculty of Science, Monash University, for a Postgraduate Publication
Award (to G.J.M.). We gratefully acknowledge support from the National
Science Foundation (CHE-0505863, 055273 and 0753807). C.St.P. was
supported by a Summer Research Fellowship from Project Advance,
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Received: January 27, 2009
Published online: April 9, 2009
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