Organometallic nickelamacrocycles of the type [(R2R′P) Ni(C2H4COO)]n: Synthesis and self-assembly to form different molecular architectures tuned by the phosphine

Article abstract of DOI:10.1021/om040111x

The reaction of succinic anhydride with a 1:2 mixture of (cod) ₂Ni and a monodentate phosphine generates reactive monomeric nickelalactones, which undergo rapid aggregation to form cyclic oligomers of the composition [(R2R′P)Ni(C₂H₄COO)]_n (R₂R′P = EtPh₂P (2), Me₃P (4), (i-Pr)₃P (5), Cy₃P (6), Et₃P (7)). The complexes were fully characterized by elemental analyses (except 4), NMR and IR spectroscopy, and X-ray crystallography of single crystals. Depending on the bulkiness of the phosphines, three types of nickelamacrocycles with different ring size and different connectivity pattern of the monomeric units are formed. The small Me₃P stabilizes a cyclic tetramer (n = 4) in which the units are linked by Ni-O-Ni bonds. This bridge is stable in thf solution. The bulkiest phosphines stabilize another type of cyclotetrameric architecture in 2, 5, and 6, in which the monomeric units are connected by Ni-O-C=O bridges. In contrast, 7, stabilized by the Et₃P ligand, forms a hexacyclic compound (n = 6) with Ni-O-C=0 bridges. The IR spectrum of 7 in thf shows two C=0 valence frequencies, indicating that at least two species are present in which the carboxylate group is differently coordinated (Ni-O and Ni-O-C=O-Ni coordination).

Full text of DOI:10.1021/om040111x

272
Organometallics 2005, 24, 272-279
Organometallic Nickelamacrocycles of the Type
[(R2R′P)Ni(C2H4COO)]n: Synthesis and Self-Assembly to
Form Different Molecular Architectures Tuned by the
Phosphine
Jens Langer, Helmar Go¨rls, Reinald Fischer, and Dirk Walther*
Institut fu¨r Anorganische und Analytische Chemie der Friedrich-Schiller-Universita¨t Jena,
August-Bebel-Strasse 2, 07743 Jena, Germany
Received August 17, 2004
The reaction of succinic anhydride with a 1:2 mixture of (cod)2Ni and a monodentate
phosphine generates reactive monomeric nickelalactones, which undergo rapid aggregation
to form cyclic oligomers of the composition [(R2R′P)Ni(C2H4COO)]n (R2R′P ) EtPh2P (2), Me3P
(4), (i-Pr)3P (5), Cy3P (6), Et3P (7)). The complexes were fully characterized by elemental
analyses (except 4), NMR and IR spectroscopy, and X-ray crystallography of single crystals.
Depending on the bulkiness of the phosphines, three types of nickelamacrocycles with
different ring size and different connectivity pattern of the monomeric units are formed.
The small Me3P stabilizes a cyclic tetramer (n ) 4) in which the units are linked by Ni-
O-Ni bonds. This bridge is stable in thf solution. The bulkiest phosphines stabilize another
type of cyclotetrameric architecture in 2, 5, and 6, in which the monomeric units are connected
by Ni-O-CdO bridges. In contrast, 7, stabilized by the Et3P ligand, forms a hexacyclic
compound (n ) 6) with Ni-O-CdO bridges. The IR spectrum of 7 in thf shows two CdO
valence frequencies, indicating that at least two species are present in which the carboxylate
group is differently coordinated (Ni-O and Ni-O-CdO-Ni coordination).
Introduction
resulting in dimeric or cyclic hexameric nickela-aza-
carboxylates, the structure of which was remarkably
influenced by the solvent and the azomethines used for
these reactions.13
The construction of well-defined supramolecular or-
ganometallics of transition metals by self-assembly of
reactive monomers is a great challenge in modern
organometallic chemistry. Although the formation of
supramolecules may dramatically influence the reactiv-
ity of organometallics, self-assembly processes of orga-
nometallics are not well understood.1-7
In previous works we have shown that the composi-
tion, structures, and reactivities of alkynol- and alkyne-
diol-nickel(0) complexes depend on the hydrogen-bonded
network formed.8-12 Furthermore, we recently reported
the reaction of CO2 and Schiff bases with (cod)2Ni,
In connection with these surprising results the ques-
tion arises if compounds of the composition [(L)nNi(C2H4-
COO)] containing the synthetically valuable nickelalac-
tone fragment can be used for the rational design of
supramolecular architectures. Generally, nickelalac-
tones of this type are rather stable monomeric com-
pounds if two ligands L are coordinated or if L is a
bidentate chelating ligand. Their preparation is easily
possible by different approaches,14-19 their chemistry is
well-investigated,20-22 and their use as stoichiometric
reagents for the synthesis of carboxylic acid derivatives
* To whom correspondence should be addressed. E-mail: cdw@
uni-jena.de.
(1) For a review see: (a) Haiduc, I.; Edelmann, F. T. Supramolecular
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Angew. Chem., Int. Ed. 2001, 40, 2022.
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Gu¨nther, W. Chem. Ber. 1996, 129, 1457.
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Imhof, W.; Go¨rls, H.; Klettke, T. Organometallics 1997, 16, 4910.
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10.1021/om040111x CCC: $30.25 © 2005 American Chemical Society
Publication on Web 12/17/2004

Organometallic Nickelamacrocycles
Organometallics, Vol. 24, No. 2, 2005 273
Scheme 1. Two Possible Monomeric Regioisomers “[(L)Ni(C2H4COO)]”
Scheme 2
offers interesting alternatives to conventional organic
molecular compounds by self-assembly. Tuning this
reaction is a synthetic challenge, as typical organo-
metallic decomposition pathways such as â-hydride
elimination or the reductive decoupling of the organic
moiety are expected to be competitive reactions. Fur-
thermore, monomeric species of the above composition
may, in principle, exist in two regioisomeric forms, A
and B, which are different in the arrangement of the
monodentate ligand (Scheme 1). Whereas B tends to
produce polymers rather than macrocyclic species by
aggregation processes, the isomer A is expected to give
highly ordered, regularly repeating molecular architec-
tures, e.g., cyclic oligomers.
To examine which monodentate ligands L stabilize
A rather than B, we investigated the reaction of
different ligands L with the monomeric complex [(py)2Ni-
(C2H4COO)]. We found that phosphines R2R′P are
suitable ligands for stabilizing A. For example, the
reaction with (o-MeOPh)Ph2P resulted in the formation
of mixed ligand complex [(o-MeOPh)Ph2P)(py)Ni(C2H4-
COO)] (1) according to Scheme 2.
The isolated yellow crystalline compound 1 was
characterized by elemental analysis and NMR measure-
ments. Furthermore, its solid-state structure was elu-
cidated by X-ray crystallography of single crystals.
Figure 1 displays the molecular structure, which shows
that the phosphine is indeed in trans position to the
oxygen atom of the carboxylate group. As expected, the
metal is in a square-planar environment and the bond
lengths and angles, listed in the caption, fall within
usual values. NMR measurements in thf-d8 gave no
evidence for the presence of isomer B in solution on the
NMR scale. To the best of our knowledge, 1 is the first
isolated example of a nickelactone bearing two different
monodentate ligands.
EtPh2P reacted with [(py)2Ni(C2H4COO)] under sub-
stitution of both pyridine ligands, resulting in the
formation of the compound [(EtPh2P)Ni(C2H4COO)]4 (2),
and Mes2PH reacts analogously to form [(Mes2PH)Ni-
(C2H4COO)]4 (3). The X-ray structures of both componds
will be discussed below.
synthesis.18,19,23-25 For example, they were found to be
useful reagents for introducing functionalized side
chains into steroids26,27 and for the formation of 3-(aryl-
mercapto)propionic acids.28
In contrast to this well-investigated field, the chem-
istry of nickelalactones containing only one monodentate
ligand (n ) 1) is still underdeveloped. Yamamoto et al.
reported so far the only isolated example of such a
compound, an oligomeric or polymeric complex of un-
known structure containing a Cy3P ligand per Ni.15
Furthermore, a related nickelacyclic amide stabilized
by Et3P with a tetrameric structure was also synthe-
sized.29 In this connection it is interesting to note that
a tetrameric palladacyclic carboxylate with Ph3P as
stabilizing ligand is also known.30
We describe here a number of new nickelalactones
“[(R2R′P)Ni(C2H4COO)]” and show that these easily
accessible compounds can undergo selective supra-
molecular aggregation resulting in nickelamacrocycles
with different ring size and different connectivity pat-
tern. The molecular architectures of these nickela-
macrocycles can be rationalized with respect to the
steric properties of the phosphine ligands.
Results and Discussion
Synthesis of the Nickelamacrocycles. Our strat-
egy was to generate reactive monomeric complexes of
the type “[(L)Ni(C2H4COO)]” in a first step which would
be able to undergo fast aggregation to form supra-
(22) Echavarren, A. M.; Castano, A. M. Adv. Met.-Org. Chem. 1998,
6, 1.
(23) Bra¨unlich, G.; Fischer, R.; Nestler, B.; Walther, D. Z. Chem.
1989, 29 (11), 417.
(24) Hoberg, H.; Ballesteros, A.; Sigan, A.; Je´gat, C.; Ba¨rhausen,
D.; Milchereit, A. J. Organomet. Chem. 1991, 407, C23.
(25) O’Brien, E. M.; Bercot, E. A.; Rovis, T. J. Am. Chem. Soc. 2003,
125 (35), 10498.
(26) Scho¨necker, B.; Walther, D.; Fischer, R.; Nestler, B.; Bra¨unlich,
G.; Eibisch, H.; Droescher, P. Tetrahedron Lett. 1990, 31 (9), 1257.
(27) Fischer, R.; Scho¨necker, B.; Walther, D. Synthesis 1993, 1267.
(28) Langer, J.; Fischer, R.; Go¨rls, H.; Walther, D. J. Organomet.
Chem. 2004, 689, 2952.
Having established this reaction for generating some
suitable complexes for investigation of aggregation
reactions, we turned our attention to a more general
synthesis. We found that the reaction of succinic anhy-
(29) Yamamoto, T.; Sano, K.; Osakada, K.; Komiya, S.; Yamamoto,
A.; Kushi, Y.; Tada, T. Organometallics 1990, 9, 2396.
(30) Ferna´ndes-Rivas, C.; Ca´rdenas, D. J.; Mart´ın-Matute, B.;
Monge, AÄ .; Gutie´rrez-Puebla, E.; Echavarren, A. M. Organometallics
2001, 20, 2998.

274 Organometallics, Vol. 24, No. 2, 2005
Langer et al.
Figure 2. ORTEP drawing of complex 4 (50% probability
level, H atoms are omitted for clarity). Selected bond
distances (Å) and bond angles (deg): Ni-O1 1.926(3), Ni-
C1 1.913(5), Ni-P1 2.1216(12), Ni-O1A 1.974(3), O1-C3
1.310(5), O2-C3 1.218(5), C1-C2 1.469(8), C2-C3
1.485(6), Ni‚‚‚NiC 3.781(2), P1‚‚‚P1A 6.157(2), P1-Ni-O1A
96.34(8), O1-Ni-O1A 89.29(11), P1-Ni-C1 88.45(16),
C1-Ni-O1 85.85(17). Symmetry transformations used to
generate equivalent atoms: #A z-1/2, -y+1/2, x+1/2.
Figure 1. ORTEP drawing of complex 1 (50% probability
level, H atoms are omitted for clarity). Selected bond
distances (Å) and bond angles (deg): Ni-O1 1.899(3), Ni-
C1 1.939(5), Ni-N 1.950(4), Ni-P 2.1323(13), O1-C3
1.295(6), O2-C3 1.236(6), C1-C2 1.518(7), C2-C3
1.522(6), N-Ni-P 99.77(13), N-Ni-O1 87.35(16), P-Ni-
C1 88.00(15), C1-Ni-O1 85.35(17).
Scheme 3. Tuning the Type of Nickelmacrocycles
by Monodentate Phosphines
Ni-CH2 group at δ ) 0.09 ppm. The H atoms of the
second CH2 group are magnetically unequal, so for each
H atom a separate multiplet at 1.92 and 2.47 ppm was
observed, suggesting the formation of an oligomeric
assembly. Only one 31P signal at -3.5 ppm in benzene-
d6 was observed, confirming the symmetrical structure
of the complex. The CdO stretching frequency at 1646
cm-1 in Nujol suspension is comparable with those of
complexes where the COO group is coordinated only via
the C-O group.14,16 This assumption is confirmed by
X-ray diffraction analysis of a single crystal, grown from
toluene. Figure 2 shows that 4 forms a tetrameric
nickelamacrocycle in the solid state, containing an inner
eight-membered Ni4O4 ring. The square-planar coordi-
nation sphere of each nickel center is formed by a
phosphorus atom, one oxygen atom of the COO group,
a carbon atom of the cyclic propionate, and the endo-
cyclic oxygen atom of the neighboring nickelacyclic unit.
The bond lengths and angles, listed in the caption, lie
in the range of typical values and therefore need no
further discussion.
If EtPh2P is used as supporting ligand, another type
of cyclic oligomers is generated. This is indicated by a
strongly shifted CdO stretching frequency at 1558 cm-1
of the isolated compound 2, suggesting the coordination
of the CdO group. The molecular structure of 2,
determined by X-ray diffraction analysis of single
crystals, shows a tetrameric complex with a pattern of
connection that is different from that of 4 (Figure 3,
Scheme 3).
In contrast to 4, in compound 2 the fourth donor atom
of the square-planar coordinated nickel is not the
endocyclic but the exocyclic oxygen atom of the neigh-
boring nickelalactone unit. This results in the formation
of a larger, 16-membered macrocycle containing the
inner unit [-Ni-O-C-O-]4 (type II in Scheme 3). A
noteworthy feature of the macrocycles of type II is seen
in a view of the lattice along the c axis in Figure 4, which
shows (for 2 as an example) that the packing results in
the formation of channels.
dride with (cod)2Ni in the presence of a monodentate
phosphine in thf using a modified method developed by
Uhlig et al.14 is a simple way for synthesizing a great
number of complexes of the type [(R2R′P)Ni(C2H4-
COO)]n. Scheme 3 shows that three different types of
nickelamacrocycles were found to be formed by self-
assembly of the monomeric compounds “[(R2R′P)Ni(C2H4-
COO)]”. Size and connectivity patterns of these cyclic
compounds are affected by the nature of the phosphines.
Structures of the Nickelamacrocycles. With L )
Me3P complex 4 is generated in good yield (78%). Its
1H NMR spectrum (in toluene-d8) exhibits a doublet for
the CH3 groups at δ ) 1.10 ppm and a multiplet for the

Organometallic Nickelamacrocycles
Organometallics, Vol. 24, No. 2, 2005 275
Figure 5. ORTEP drawing of complex 6 (50% probability
level, H atoms are omitted for clarity). Selected bond
distances (Å) and bond angles (deg): Ni-O1 1.902(3), Ni-
C1 1.933(4), Ni-P1 2.1454(11), Ni-O2A 1.987(3), O1-C3
1.270(5), O2-C3 1.248(5), C1-C2 1.533(6), C2-C3
1.509(5), Ni‚‚‚NiC 5.416(2), P1‚‚‚P1A 7.717(2), P1-Ni-O2A
95.59(9), O1-Ni-O2A 85.40(12), P1-Ni-C1 94.50(12),
C1-Ni-O1 84.57(15). Symmetry transformations used to
generate equivalent atoms: #A y, -x+1, -z.
Figure 3. ORTEP drawing of complex 2 (50% probability
level, H atoms are omitted for clarity). Selected bond
distances (Å) and bond angles (deg): Ni-O1 1.891(3), Ni-
C1 1.912(4), Ni-P1 2.1237(11), Ni-O2A 1.979(3), O1-C3
1.269(4), O2-C3 1.261(4), C1-C2 1.519(5), C2-C3
1.495(5), Ni‚‚‚NiC 5.488(2), P1‚‚‚P1A 7.728(2), P1-Ni-O2A
95.66(8), O1-Ni-O2A 85.39(11), P1-Ni-C1 93.59(12),
C1-Ni-O1 85.48(15). Symmetry transformations used to
generate equivalent atoms: #A y, -x+1, -z.
Figure 4. Part of the crystal structure of 2 (view along c
Figure 6. ORTEP drawing of complex 7‚DMF (50%
probability level, only one of two independent hexamers
shown, H atoms are omitted for clarity). Selected bond
distances (Å) and bond angles (deg): NiA-O1A 1.925(3),
NiA-C1A 1.914(5), NiA-P1A 2.1207(15), NiA-O2B
1.943(3), O1A-C3A 1.274(6), O2A-C3A 1.246(6), C1A-
C2A 1.522(7), C2A-C3A 1.512(7), NiA‚‚‚NiAA 10.559(2),
NiB‚‚‚NiBA 8.560(2), NiC‚‚‚NiCA 8.708(2), P1A‚‚‚P1B
7.517(2), P1A‚‚‚P1CA 7.380(2), P1B‚‚‚P1C 6.914(2), P1A-
NiA-O2B 98.57(11), O1A-NiA-O2B 88.48(14), P1A-
NiA-C1A 88.09(16), C1A-NiA-O1A 85.87(19).
axis; H atoms are omitted for clarity).
The same type of complex was generated when i-Pr3P
was used as ligand, resulting in complex 5. Due to the
highly disordered isopropyl groups in 5, only the struc-
ture motif (not depicted) was obtained by X-ray crystal-
lography (see Experimental Section). Complex 3 (L )
Mes2PH), which was accessible in pure form only by
ligand exchange starting from [(py)2Ni(C2H4COO)]
(Scheme 2), stabilizes a cyclic tetramer of the type II as
well, according to the X-ray analysis of single crystals
(not depicted).
6 has the same cyclic tetrameric structure as found for
2, 3, and 5.
A nickelalactone with Cy3P as supporting ligand was
already prepared by Yamamoto et al.15 through an
oxidative addition/insertion sequence of acrylic acid on
a Cy3P-stabilized Ni(0) center. Its structure in the solid
state was so far not determined. Starting from succinic
anhydride and (cod)2Ni, we could obtain single crystals
of [(Cy3P)Ni(C2H4COO)]4 (6) directly from the reaction
mixture. In the infrared spectrum of compound 6 the
The third type of nickelamacrocyle was formed when
Et3P was used as supporting ligand (Scheme 3). In the
resulting compound 7, the CdO stretching frequency
is also strongly shifted to 1563 cm-1, indicating that the
exocyclic oxygen of the carboxylate function should act
as donor ligand for an adjacent nickel center, similarly
to the tetrameric compounds 2, 3, 5, and 6. However,
the molecular structure determined by X-ray crystal-
lography of single crystals shows a very different
architecture (Figure 6). In 7 six monomeric units are
connected via a Ni-O-CdO-Ni coordination mode,
yielding a cyclic hexameric compound that contains a
24-membered macrocycle of the type [-Ni-O-C-
CdO stretching frequency was observed at 1567 cm-1
,
comparable with that reported in the literature for
[(Cy3P)Ni(C2H4COO)]n (1570 cm-1), so it seems that
those two compounds are actually the same. X-ray
crystallography of single crystals (Figure 5) shows that

276 Organometallics, Vol. 24, No. 2, 2005
Langer et al.
Table 1. Electronic and Steric Properties of the Phosphines and the Structures of the Metallacycles
ligand
Me3P
Et3P
Mes2PH
EtPh2P
i-Pr3P
160
Cy3P
cone angle θ31 [deg]
cone angle θ (determ) [deg]
∑øi31
118
132
140
170
123
162a
161b
13.7
tetramer 3
type II
173
178
7.8
5.4
10.4
3.0
tetramer 5
type II
0.3
metallamacrocycle
tetramer 4
type I
hexamer 7
type III
tetramer 2
type II
tetramer 6
type II
a Average cone angle (6 independent monomeric units). b Average cone angle (4 independent monomeric units).
Table 2. CdO Stretching Frequencies in Solid State and Solution
ν(CdO) [cm-1
(Nujol mull)
]
ν(CdO) [cm-1
]
ν(CdO) [cm-1
(thf)
]
compound
(toluene)
[(Me3P)Ni(C2H4COO)]4 (4)
[(Et3P)Ni(C2H4COO)]6‚ether (7a)
[(i-Pr3P)Ni(C2H4COO)]4 (5)
1646
1563
1570
1657
1677 + 1572
1572
1659
1679 + 1572
1573
O-]6. In the inner part of the nickelamacrocycle one
solvent molecule is embedded (dmf or ether depending
on the solvents used for the crystallization of single
crystals). It seems that those solvent molecules act as
templates for the formation of a cyclic hexameric
structure.
type I complex but shorter than in the type II complexes.
From these results it can be concluded that it is possible
to predict the structure of the cyclic oligomers from the
minimum cone angle (as defined by Tolman) of the used
phosphine, if there are internal degrees of freedom. The
cone angles, extracted from the molecular structure of
the complexes, are larger but show, in principle, the
same order of the ligands. It seems, for highly unsym-
metrical ligands such as Mes2PH, that the cone angle
is only a coarse tool for describing their steric properties.
Behavior of the Macrocyclic Nickelalactones in
Solution. Whether the isolated nickelamacrocycles are
stable in solution or undergo rearrangement reactions
to form other oligomers or solvent-stabilized monomers
is an open question. Most of the nickelamacrocycles are
soluble in solvents such as thf, dmf, and toluene (except
6), however only sparingly soluble in n-pentane. There-
fore, it was possible to crystallize some complexes from
different solvents. For example, crystals of compound
5 (L ) i-Pr3P) were obtained from toluene as well as
from thf; however independently from the nature of the
solvent the same cyclic tetramer was formed. Similarly,
as mentioned above, single crystals of [(Et3P)Ni(C2H4-
COO)]6‚solvent 7 of the same molecular architecture can
be prepared with both ether and dmf.
To examine the behavior of the complexes directly in
solution, we investigated the CdO stretching frequen-
cies of compounds of each type in two solvents of
different polarity (toluene und thf) and compared these
values with νCO of the compounds in the solid state
(Table 2).
Table 2 reveals that there is only a little shift of νCO
in 4 when the solid compound is dissolved in thf or
toluene, indicating that the connectivity pattern re-
mains stable in solution. As mentioned above, the NMR
spectra give evidence for the presence of only one isomer
in solution. Therefore, we can conclude that the struc-
ture found in the solid state is present in these solutions
as well. A representative of the type III compounds [(i-
Pr3P)Ni(C2H4COO)]4 (5) shows the same behavior (Table
1). The CdO valence frequency of solutions lies in the
same range as νCO of the solid state. This suggests that
only one isomer is present in both thf and toluene
solutions, having the same Ni-OCO-Ni bridges as
found in the crystalline compound.
Influence of the Phosphine on the Molecular
Architecture of the Nickelamacrocycles. To obtain
further information about the influence of the phos-
phines on the structures of the cyclic oligomers, we
determined whether electronic or steric properties of the
ligands decide which types of nickelamacrocycles are
built up by self-assembly of the monomeric units.
An easy way to describe these properties of the
phosphines is the comparison of their electronic and
steric parameters øi and θ, introduced by Tolman31
(Table 1). For the steric parameter θ, however, not only
the published values were used but also the cone angle
of the phosphines extracted from the X-ray crystal
structures of the nickelamacrocycles. Details of the
calculation are described in the Experimental Section.
The results are summarized in Table 1.
Table 1 clearly shows that the electronic properties
of the phosphines have no effect on the type of oligomers
formed. Cy3P, the ligand with the lowest value for ∑øi,
and Mes2PH, the phosphine with the highest value for
∑øi, stabilize the same type of macrocycle. On the other
hand, there is a remarkable influence of the steric effect
on the molecular architecture. Nickelalactones with
small ligands (Me3P) form the smallest metallacycle
containing [-Ni-O-Ni-] bridges in the Ni4O4 eight-
membered ring of the tetramer (Ni‚‚‚NiC 3.781(2) Å).
The distance between two neighboring phosphorus
atoms (P1‚‚‚P1A) in 3 is approximately 6.2 Å. In
contrast, phosphines with large cone angles can stabilize
macrocycles only with the larger 16-membered ring
containing [-Ni-O-CdO-] bridges (2: Ni‚‚‚NiC 5.488(2)
Å; 6: Ni‚‚‚NiC 5.416(2) Å). In these complexes of type
II the P1‚‚‚P1A distances are approximately 7.7 Å.
The effect of Et3P on the macrocyclic structure is of
particular interest for understanding the aggregation
reactions. Since Et3P is larger than Me3P, it is not
suitable for stabilizing the type I macrocycle. On the
other hand, the steric demand of Et3P is smaller than
that of the other phosphines used in this study. There-
fore, Et3P is able to generate a third type of nickela-
macrocycles, a hexameric derivative in which the aver-
age P‚‚‚P′ distance of about 7.2 Å is longer than in the
In contrast, the nickelamacrocycle 7 (the compound
of type III) behaves differently. When this cyclic hex-
amer was dissolved in thf or toluene, two CdO frequen-
cies of approximately the same intensity (1677, 1572
(31) Tolman, C. A. Chem. Rev. 1977, 77 (3), 313.

Organometallic Nickelamacrocycles
Organometallics, Vol. 24, No. 2, 2005 277
Experimental Section
General Considerations. 1H NMR and 13C NMR spectra
were recorded at ambient temperature on a Bruker AC 200
or AC 400 MHz spectrometer. All spectra were referenced to
TMS or deuterated solvent as an internal standard. IR
measurements were carried out on a Perkin-Elmer System
2000 FT-IR.
All manipulations were carried out by using Schlenk
techniques under an atmosphere of argon. Prior to use,
tetrahydrofuran, toluene, and diethyl ether were dried over
potassium hydroxide and distilled over Na/benzophenone. Dmf
and pyridine were distilled over CaH2. [(py)2Ni(C2H4COO)] and
(cod)2Ni were prepared according to literature procedures.28,32
Synthesis of [(o-MeOPhPh2P)(py)Ni(C2H4COO)]‚thf (1).
A mixture of [(py)2Ni(C2H4COO)] (0.75 g, 2.60 mmol) and
EtPh2P (0.76 g, 2.60 mmol) in dmf (15 mL) was stirred for 1 h
at rt. The solution was filtered to remove impurities, and the
solvent was slowly distilled of at rt under reduced pressure.
The resulting sticky oil was dissolved in thf (15 mL) and kept
at -20 °C for 2 days. The formed, yellow product was collected
by filtration and dried in a vacuum. Yield: 0.91 g (61%). C31H34-
PNNiO4 (574.28) calcd: C 64.84, H 5.97, N 2.44. Found: C
Figure 7. ORTEP drawing of complex 8 (50% probability
level, uncoordinated pyridine and H atoms, except the one
bond to O3, are omitted for clarity). Selected bond distances
(Å) and bond angles (deg): Ni-O1 1.9185(19), Ni-C1
1.927(3), Ni-P 2.1747(7), Ni-N1 1.994(2), O1-C3
1.314(3), O2-C3 1.219(3), C1-C2 1.521(4), C2-C3
1.506(4), O1‚‚‚O3 2.732(2), P-Ni-N1 100.47(6), O1-Ni-
N1 85.27(9), P-Ni-C1 92.05(8), C1-Ni-O1 83.75(10).
1
64.80, H 5.96, N 2.31. IR (Nujol, cm-1): ν(CdO) 1628 (s). H
NMR (200 MHz, dmso-d6, 25 °C): δ -0.07 (m, 2H, Ni-CH2),
1.70-1.80 (m, 2H + 4H, CH2COO + CH2 thf), 3.59 (t, 4H, CH2
thf), 3.87 (s, 3H, CH3), 6.85-7.75 (m, 15H, CH Phenyl + py),
8.46 (br, 2H, CH py) ppm. 13C{1H} NMR (100 MHz, dmso-d6,
cm-1 in thf; 1679, 1572 cm-1 in toluene) were observed
(Table 1). This shows that at least two species with
differently coordinated carboxylate groups do exist in
solution. This suggestion is underlined by two different
31P signals (26.5 (s) and 27.3 (br) ppm) for this nickela-
cycle in thf-d8 in the 31P NMR spectrum. From these
data, however, it cannot be concluded which oligomers
may be formed in solution. In contrast, only one 31P
signal at 28.7 (s) ppm was found, when dmf-d7 was used
as solvent for 7. It is also noteworthy that attempts to
crystallize other than the cyclic hexamer were unsuc-
cessful so far.
25 °C): δ 5.0 (Ni-CH2), 25.0 (2 × CH2 thf), 38.3 (CH2COO),
1
55.9 (CH3), 66.9 (2 × CH2 thf), 111.8 (CH), 118.0 (d, JC,P
)
2
44.9 Hz, i-C), 120.6 (d, JC,P ) 7.3 Hz, CH), 123.9 (2 × m-CH
3
py), 128.2 (d, JC,P ) 9.2 Hz, 4 × m-CH phenyl), 129.9 (2 ×
1
CH), 130.6 (d, JC,P ) 44.6 Hz, 2 × i-C phenyl), 132.6 (2 ×
CH), 133.6 (d, 2JC,P ) 11.1 Hz, 4 × o-CH phenyl), 136.8 (p-CH
py), 149.9 (2 × o-CH py), 160.0 (i-C), 185.1 (COO) ppm. 31P-
{1H} NMR (81 MHz, thf-d8, 25 °C): δ 32.2 (s) ppm. Crystals,
suitable for X-ray diffraction, were obtained from a solution
of thf.
Synthesis of [(EtPh2P)Ni(C2H4COO)]4 (2). Method 1.
EtPh2P (0.32 g, 1.49 mmol) was added to a stirred solution of
[(py)2Ni(C2H4COO)] (0.43 g, 1.49 mmol) in dmf (10 mL). After
stirring the resulting yellow brown solution for 30 min at rt,
the solvent was slowly distilled off at reduced pressure. The
sticky brown residue was treated with ether (10 mL) with
rapid stirring. The formed yellow solid was collected by
filtration and dried in a vacuum. Yield: 0.39 g (76%).
Method 2. To a stirred mixture of (cod)2Ni (1.30 g, 4.72
mmol) and EtPh2P (1.95 g, 9.10 mmol) in thf (20 mL) was
added succinic anhydride at 0 °C. The solution was allowed
to warm to rt and was stirred for 1 h. Then the solution was
heated to 40 °C for an additional 30 min. The solvent was
removed in a vacuum, ether (20 mL) was added, and formed
solids were removed by filtration. From the clear solution,
brown crystals were obtained at 5 °C after a few days together
with some yellow precipitate. The solution with the yellow solid
was decanted, and the separated crystals were dried in a
vacuum. Yield: 0.55 g (53%). C68H76P4Ni4O8 (1380.02) calcd:
C 59.18, H 5.55. Found: C 58.87, H 5.49. IR (Nujol, cm-1):
In addition, solvents with strong ligand properties
such as pyridine are able to split the Ni-O-CdO-Ni
bridges, resulting in the formation of monomeric com-
pounds. For example, complex [(Cy3P)Ni(C2H4COO)]4
(6), which is insoluble in most organic solvents, readily
dissolves in pyridine. From a saturated solution of 6 in
pyridine golden single crystals of the monomeric com-
plex [(Cy3P)(py)Ni(C2H4COO)‚‚‚EtOH]‚0.5 py (8) can be
isolated upon addition of a small amount of EtOH.
Figure 7 reveals the molecular structure, which was
elucidated by X-ray crystallography, and lists selected
bond lengths and angles. The arrangement around the
nickel atom is essentially the same as in complex 1, but
the larger cone angle of Cy3P results in stronger
distortion of the square-planar geometry (P-Ni-N )
100.47(6)°). The alcohol forms a hydrogen bond to the
endocyclic oxygen of the carboxylate function.
1
ν(CdO) 1558 (s). H NMR (400 MHz, thf-d8, 25 °C): δ -0.24
Concluding Remarks
(m, 2H, Ni-CH2), 1.27 (dt, 3JH,H ) 7.2 Hz, 3JP,H ) 16.4 Hz, 3H,
CH3), 1.46 (m, 1H, CHH′-COO), 1.88 (m, 1H, CHH′-COO), 2.18
(m, 2H, CH2), 7.38 (m, 6H, CH phenyl), 7.97 (m, 4H, CH
phenyl) ppm. 13C{1H} NMR (100 MHz, thf-d8, 25 °C): δ 0.2
(d, 2JC,P ) 33.8 Hz, Ni-CH2), 9.5 (s, CH3), 20.0 (d, 1JC,P ) 26.6
In conclusion, we have shown that a variety of
supramolecular nickelamacrocycles are easily accessible
either by reaction of succinic anhydride with a 2:1
mixture of a monodentate phosphine and (cod)2Ni or by
displacement of two pyridines in [(py)2Ni(C2H4COO)] by
one monodentate phosphine. The metallamacrocycles
form three different types of molecular architectures
controlled by steric effects of the phosphines. In thf or
toluene solution, the cyclic oligomers are stable, except
the cyclic hexamer 7.
3
Hz, CH2), 38.9 (s, CH2), 128.6 (d, JC,P ) 7.0 Hz, 2 × m-CH),
128.7 (d, 3JC,P ) 7.0 Hz, 2 × m-CH), 129.8 (s, p-CH), 130.0 (s,
1
1
p-CH), 133.5 (d, JC,P ) 42.3 Hz, i-C), 134.0 (d, JC,P ) 42.3
Hz, i-C), 134.0 (d, 2JC,P ) 10.1 Hz, 2 × o-CH), 134.4 (d, 2JC,P
)
(32) Wilke, G.; Bogdanovic, B.; Ko¨rner, M. Liebigs Ann. Chem. 1966,
699, 1.

278 Organometallics, Vol. 24, No. 2, 2005
Langer et al.
10.1 Hz, 2 × o-CH), 188.9 (s, COO) ppm. 31P{1H} NMR (81
MHz, thf-d8, 25 °C): δ 32.6 (s) ppm.
removed. Suitable crystals of 6 for X-ray diffraction were
obtained from this reaction mixture at rt besides side products.
IR measurements suggest 6 to be essentially the same product
as [(Cy3P)Ni(C2H4COO)]n described by Yamamoto previously.
IR (Nujol, cm-1): ν(CdO) 1567 (s) (1570 lit.15).
Synthesis of [(Mes2PH)Ni(C2H4COO)]4 (3). [(py)2Ni(C2H4-
COO)] (0.36 g, 1.25 mmol) was dissolved in dmf (10 mL). After
Mes2PH (0.34 g, 1.26 mmol) was added, the resulting solution
was stirred for 30 min at rt. After that, the solvent was slowly
removed in a vacuum, yielding a brown sticky residue. To this
oil was added ether (10 mL) with rapid stirring. The yellow
solid formed was separated by filtration and dried in a vacuum.
Yield: 0.45 g of crude product (contains dmf and [(py)2Ni(C2H4-
COO)]). For analytical characterization, the crude product was
recrystallized from thf, resulting in [(Mes2PH)Ni(C2H4COO)]4‚
THF‚DMF. C91H123P4NNi4O10 (1748.66) calcd: C 62.46, H 7.09,
N 0.80. Found: C 62.31, H 7.07, N 0.63. IR (Nujol, cm-1):
Synthesis of [(Et3P)Ni(C2H4COO)]6‚Solvent (7). A sus-
pension of (cod)2Ni (1.47 g, 5.34 mmol) in thf (10 mL) was
mixed with Et3P (1.56 mL, 10.68 mmol). After the yellow
(cod)2Ni was completely dissolved, succinic anhydride was
added. The reaction mixture was stirred 30 min at rt and
additionally for 30 min at 40 °C. After cooling to rt the solvent
was removed in a vacuum. The red, sticky residue was
dissolved in ether (10 mL) and filtered through Celite. From
this clear, reddish solution yellow-brown crystals of [(Et3P)-
Ni(C2H4COO)]6‚Et2O (7a) could be obtained at 5 °C overnight
besides some yellow amorphous precipitate. These crystals
were suitable for X-ray diffraction. Analogously, [(Et3P)Ni-
(C2H4COO)]6‚DMF (7b) was formed if dmf (5 mL) was used
1
ν(CdO) 1566 (s). H NMR (400 MHz, dmf-d7, 25 °C): δ 0.30
(m, 8H, Ni-CH2), 1.78 (m, 4H, CH2 thf), 1.89 (m, 8H, CH2-
COO), 2.26 (s, 24H, p-CH3), 2.74 (s, 48H, o-CH3, signal overlaps
with one signal of the solvent), 2.78 (s, 3H, CH3 dmf), 2.95 (s,
1
3H, CH3 dmf), 3.63 (m, 4H, O-CH2 thf), 5.86 (d, JP,H ) 371.0
instead of Et2O. C57H121P6NNi6O13 (7b) (1566.59) calcd:
C
Hz, 4H, PH), 6.98 (s, 16H, CH), 8.02 (s, HCO dmf) ppm. 13C-
43.70, H 7.79, N 0.89. Found: C 43.73, H 7.87, N 0.81. IR
{1H} NMR (100 MHz, dmf-d7, 25 °C): δ 0.8 (d,2JP,C ) 25.9 Hz,
1
(Nujol, cm-1): ν(CdO) 1563 (s). H NMR (200 MHz, dmf-d7,
3
Ni-CH2), 20.9 (s, p-CH3), 23.0 (d, JP,C ) 8.3 Hz, o-CH3), 26.0
25 °C): δ 0.13 (br, 2H, Ni-CH2), 1.00-1.80 (m, 15H, CH3
+
CH2), 1.83 (br, 2H, CH2-COO) ppm. 13C{1H} NMR (50 MHz,
dmf-d7, 25 °C): δ -3.8 (d, 2JC,P ) 30.6 Hz, Ni-CH2), 8.4 (s, 3 ×
(s, CH2 thf), 39.7 (s, CH2-COO), 67.9 (s, O-CH2 thf), 123.2 (d,
1JP,C ) 38.2 Hz, P-i-C), 130.4 (d, 3JP,C ) 6.9 Hz, CH), 140.7 (s,
2
i-C), 142.5 (d, JP,C ) 8.3 Hz, i-C), 184.7 (s, COO) ppm. 31P
1
CH3), 14.6 (d, JC,P ) 20.6 Hz, 3 × CH2), 39.1 (s, CH2), 185.1
1
(s, COO) ppm. 31P{1H} NMR (81 MHz, dmf-d7, 25 °C): δ 28.7
NMR (81 MHz, dmso-d6, 25 °C): δ -29.1 (d, JP,H ) 372 Hz)
ppm. Single crystals suitable for X-ray diffraction were ob-
tained from a thf/ether mixture.
ppm.
Synthesis of [(Cy3P)(py)Ni(C2H4COO)‚‚‚EtOH]‚0.5 py
(8). Yellow 6 was dissolved in pyridine, and a saturated,
greenish yellow solution was obtained. After addition of a small
amount of EtOH and standing at 5 °C for a few days golden
crystals were formed. These crystals were collected by filtration
and dried in a vacuum. C30.5H50.5PN1.5Ni4O8 (575.91) calcd: C
63.61, H 8.84, N 3.65. Found: C 63.78, H 9.06, N 3.42. IR
(Nujol, cm-1): ν(O-H) 3336 (s) ν(CdO) 1650 (s). 13C{1H} NMR
Synthesis of [(Me3P)Ni(C2H4COO)]4 (4). thf (10 mL) was
added to (Me3P)2Ni(cod) (1.5 g, 4.7 mmol). The resulting
solution was cooled to -10 °C, and succinic anhydride (0.31 g,
3.13 mmol) was added. Then the solution was slowly heated
to 35 °C and stirred for 45 min at this temperature. The
resulting, yellow solid was collected by filtration at rt and dried
under reduced pressure. Yield: 0.55 g (62%), C24H52P4Ni4O8
(827.34). The elemental data for C showed in each of three
measurements of different crystalline samples too high values
with the same deviation from calculated value. Possibly, a
pyrolysis product interfered with CO2 detection. IR (Nujol,
cm-1): ν(CdO) 1646 (s). 1H NMR (400 MHz, toluene-d8, 25
°C): δ 0.09 (m, 2H, Ni-CH2), 1.10 (d, 2JP,H ) 10.2 Hz, 9H, CH3),
1.92 (m, 1H, CHH′-COO), 2.47 (dddd, J ) 3.2 Hz, J ) 8.2 Hz,
2
(100 MHz, pyridine-d5, 25 °C): δ 1.2 (d, JC,P ) 29.8 Hz, Ni-
CH2), 19.1 (s, CH3 EtOH ), 27.9 (s, 6 × CH2), 30.0 (s, 3 × CH2),
2
1
31.4 (d, JC,P ) 12.4 Hz, 6 × CH2), 33.8 (d, JC,P ) 20.5 Hz, 3
× CH), 39.7 (d, 3JC,P ) 2.1 Hz, CH2-COO), 57.2 (s, CH2 EtOH),
187.4 (s, br) ppm. 31P{1H} NMR (81 MHz, pyridine-d5, 25 °C):
δ 37.6 ppm. Besides the signals of 8 also a set of signals for
free phosphine and for the bis(pyridine-d5) complex in equi-
librium with 8 was observed.
2
J ) 8.2 Hz, JH,H ) 17.3 Hz, 1H, CHH′-COO) ppm. 13C{1H}
2
NMR (100 MHz, benzene-d6, 25 °C): δ -3.0 (d, JP,C ) 36.3
Crystal Structure Determination. The intensity data for
the compounds were collected on a Nonius KappaCCD diffrac-
tometer, using graphite-monochromated Mo KR radiation.
Data were corrected for Lorentz and polarization effects, but
not for absorption effects.33,34
1
Hz, Ni-CH2), 12.7 (d, JP,C ) 28.7 Hz, CH3), 37.3 (CH2-COO),
185.4 (COO) ppm. 31P{1H} NMR (162 MHz, benzene-d6, 25
°C): δ -3.5 ppm. Single crystals suitable for the X-ray
diffraction were obtained from a solution of toluene.
Synthesis of [(i-Pr3P)Ni(C2H4COO)]4 (5). Isopropyl3P
(1.82 mL, 9.3 mmol) was added to a suspension of (cod)2Ni (1.28
g, 4.65 mmol) in thf (20 mL). To the resulting solution was
added succinic anhydride (0.31 g, 3.1 mmol), and the mixture
was stirred for 30 min at rt and for an additional 30 min at
40 °C. A yellow precipitate formed and was collected by
filtration, washed with ether, and dried in a vacuum. Yield:
0.76 g (84%). C48H100P4Ni4O8 (1163.99) calcd: C 49.53, H 8.66.
Found: C 49.41, H 8.38. IR (Nujol, cm-1): ν(CdO) 1570 (s).
1H NMR (400 MHz, thf-d8, 25 °C): δ -0.13 (br, 1H, Ni-CHH′),
0.26 (br, 1H, Ni-CHH′), 1.30-1.45 (m, 18H, CH3), 1.78 (br, 1H,
The structures were solved by direct methods (SHELXS35)
2
and refined by full-matrix least-squares techniques against Fo
(SHELXL-9736). The hydrogen atom of the hydroxyl group of
the ethanol molecules of 8 was located by difference Fourier
synthesis and refined isotropically. All other hydrogen atoms
were included at calculated positions with fixed thermal
parameters. All non-hydrogen atoms were refined anisotropi-
cally.36 Compound 3 contains disordered thf molecules result-
ing in the insufficient quality of the data (R1 ) 11.6%). In the
case of complex 5 the errors of the cell parameters are very
small; however, the isopropyl groups cause a disorder that
could not be solved. Therefore, we will publish the conforma-
tion of the molecules and the crystallographic data of only 3
and 5. We will not deposit the data in the Cambridge
3
CHH′-COO), 1.86 (m, JH,H ) 7.2 Hz, 3H, CH), 2.07 (br, 1H,
CHH′-COO) ppm. 13C{1H} NMR (50 MHz, thf-d8, 25 °C): δ
2
1
-5.2 (d, JC,P ) 32.7 Hz, Ni-CH2), 19.9 (s, CH3), 23.7 (d, JC,P
3
3
) 20.1 Hz, CH), 40.4 (d, JC,P ) 2.8 Hz, CH2), 190.7 (m, JC,P
) 1.7 Hz, COO) ppm. 31P{1H} NMR (162 MHz, thf-d8, 25 °C):
δ 47.3 (s) ppm. Single crystals suitable for X-ray diffraction
were obtained from a solution of toluene or thf.
(33) COLLECT, Data Collection Software; Nonius B.V.: Nether-
lands, 1998.
(34) Otwinowski, Z.; Minor, W. Processing of X-Ray Diffraction Data
Collected in Oscillation Mode. In Methods in Enzymology, Macro-
molecular Crystallography, Part A; Carter, C. W., Sweet, R. M., Eds.;
Academic Press: New York, 1997; Vol. 276, pp 307-326.
(35) Sheldrick, G. M. Acta Crystallogr. Sect. A 1990, 46, 467.
(36) Sheldrick, G. M. SHELXL-97 (Release 97-2); University of
Go¨ttingen: Germany, 1997.
Synthesis of [(Cy3P)Ni(C2H4COO)]4 (6). A clear solution
of (cod)2Ni (0.52 g, 1.89 mmol) and Cy3P (1.06 g, 3.78 mmol)
in thf (20 mL) was prepared. Succinic anhydride (0.13 g, 1.30
mmol) was added at 5 °C with rapid stirring. After the
anhydride was completely dissolved, the stirring bar was

Organometallic Nickelamacrocycles
Organometallics, Vol. 24, No. 2, 2005 279
Crystallographic Data Centre. XP (SIEMENS Analytical X-ray
Instruments, Inc.) was used for structure representations.
Determination of the cone angles from solid-state structure
was performed as follows. Each phosphine was treated as
unsymmetrical ligand, using θ ) (2/3)∑3i)1(θi/2) to minimize
the sum of half-angles. The angles θi/2 for each substituent
can be obtained from the angle P-Ni-H(X) by mathematical
addition of the van der Waals radii to the hydrogen atoms.
The hydrogen atom resulting in the highest corrected value
θi/2 is chosen.
Flack parameter 0.01(2), largest difference peak and hole
0.556/-0.411 e Å-3
.
Crystal Data for 5: C48H98Ni4O8P4, Mr ) 1161.98 g mol-1
,
yellow prism, size 0.03 × 0.03 × 0.02 mm3, tetragonalic, space
group P4h, a ) b ) 23.2593(5) Å, c ) 10.9689(2) Å, V )
5934.1(2) Å3, T ) -90 °C, Z ) 4, Fcalcd ) 1.301 g cm-3, µ(Mo
KR) ) 14.02 cm-1, F(000) ) 2488, 23 828 reflections in
h(-26/24), k(-30/28), l(-14/12), measured in the range 1.96°
e θ e 27.46°, completeness θmax ) 99.5%, 12 566 independent
reflections.
Crystal Data for 6:37 C84H148Ni4O8P4, Mr ) 1644.74 g mol-1
,
Crystal Data for 1:37 C31H34NNiO4P, Mr ) 574.27 g mol-1
,
yellow prism, size 0.03 × 0.03 × 0.02 mm3, tetragonalic, space
group I4h, a ) b ) 18.7303(4) Å, c ) 12.5854(2) Å, V )
4415.26(15) Å3, T ) -90 °C, Z ) 2, Fcalcd ) 1.237 g cm-3, µ(Mo
KR) ) 9.62 cm-1, F(000) ) 1776, 15 825 reflections in h(-23/
24), k(-23/24), l(-15/16), measured in the range 2.92° e θ e
27.48°, completeness θmax ) 99.8%, 5043 independent reflec-
tions, Rint ) 0.044, 4408 reflections with Fo > 4σ(Fo), 227
green-yellow prism, size 0.03 × 0.03 × 0.02 mm3, triclinic,
space group P1h, a ) 9.9387(3) Å, b ) 11.9818(3) Å, c ) 14.1601-
(5) Å, R ) 113.074(1)°, â ) 90.262(1)°, γ ) 112.983(1)°, V )
1403.25(7) Å3, T ) -90 °C, Z ) 2, Fcalcd ) 1.359 g cm-3, µ(Mo
KR) ) 7.85 cm-1, F(000) ) 604, 10 199 reflections in h(-12/
12), k(-15/15), l(-17/18), measured in the range 1.98° e θ e
27.42°, completeness θmax ) 99.2%, 6344 independent reflec-
tions, Rint ) 0.042, 4769 reflections with Fo > 4σ(Fo), 343
parameters, 0 restraints, R1obs ) 0.075, wR2obs ) 0.1714, R1all
) 0.104, wR2all ) 0.184, GOOF ) 1.094, largest difference peak
parameters, 0 restraints, R1obs ) 0.048, wR2obs ) 0.135, R1all
)
0.059, wR2all ) 0.144, GOOF ) 1.052, Flack parameter
0.486(19) (twin refined, meoedric twin), largest difference peak
and hole 1.772/-0.348 e Å-3
.
and hole 1.365/-0.714 e Å-3
Crystal Data for 2:37 C68H76Ni4O8P4, Mr ) 1380.01 g mol-1
.
Crystal Data for 7:37 C54H114Ni6O12P6‚C3H7NO, Mr
)
,
1566.63 g mol-1, green prism, size 0.03 × 0.03 × 0.03 mm3,
triclinic, space group P1h, a ) 15.0676(5) Å, b ) 16.0297(5) Å,
c ) 16.1476(6) Å, R ) 98.279(2)°, â ) 104.586(2)°, γ ) 93.720-
yellow-orange prism, size 0.03 × 0.03 × 0.02 mm3, tetragonalic,
space group I4h, a ) b ) 17.3790(12) Å, c ) 10.6941(6) Å, V )
3229.9(4) Å3, T ) -90 °C, Z ) 2, Fcalcd ) 1.419 g cm-3, µ(Mo
KR) ) 13.01 cm-1, F(000) ) 1440, 6056 reflections in h(-17/
22), k(-21/17), l(-13/13), measured in the range 2.24° e θ e
27.47°, completeness θmax ) 99.8%, 3507 independent reflec-
tions, Rint ) 0.046, 2782 reflections with Fo > 4σ(Fo), 190
(2)°, V ) 3714.2(2) Å3, T ) -90 °C, Z ) 2, Fcalcd ) 1.401 g cm-3
,
µ(Mo KR) ) 16.72 cm-1, F(000) ) 1664, 25 864 reflections in
h(-18/19), k(-20/19), l(-19/20), measured in the range 2.64°
e θ e 27.46°, completeness θmax ) 97.3%, 16 553 independent
reflections, Rint ) 0.052, 10 794 reflections with Fo > 4σ(Fo),
761 parameters, 0 restraints, R1obs ) 0.062, wR2obs ) 0.137,
R1all ) 0.112, wR2all ) 0.165, GOOF ) 1.037, largest difference
parameters, 0 restraints, R1obs ) 0.043, wR2obs ) 0.077, R1all
0.068, wR2all ) 0.085, GOOF ) 1.015, Flack parameter -0.025-
(17), largest difference peak and hole 0.277/-0.287 e Å-3
)
.
peak and hole 1.341/-0.677 e Å-3
.
Crystal Data for 3: C84H108Ni4O8P4‚C4H8O‚0.5“CH4O”, Mr
) 1692.55 g mol-1, yellow prism, size 0.02 × 0.02 × 0.01 mm3,
triclinic, space group P1h, a ) 13.7113(7) Å, b ) 17.3512(6) Å,
c ) 22.2884(11) Å, R ) 67.570(3)°, â ) 72.655(2)°, γ )
84.481(3)°, V ) 4677.6(4) Å3, T ) -90 °C, Z ) 2, Fcalcd ) 1.202
g cm-3, µ(Mo KR) ) 9.12 cm-1, F(000) ) 1794, 31 763
reflections in h(-17/16), k(-20/22), l(-28/27), measured in the
range 2.54° e θ e 27.49°, completeness θmax ) 96.9%, 20 812
independent reflections.
Crystal Data for 8:37 C28H48NNiO3P‚1/2 C5H5N, Mr
)
575.90 g mol-1, yellow prism, size 0.12 × 0.12 × 0.10 mm3,
triclinic, space group P1h, a ) 9.3259(4) Å, b ) 12.5108(7) Å, c
) 13.5807(8) Å, R ) 88.669(3)°, â ) 87.244(3)°, γ ) 70.259-
(3)°, V ) 1489.6(1) Å3, T ) -90 °C, Z ) 2, Fcalcd ) 1.284 g cm-3
,
µ(Mo KR) ) 7.37 cm-1, F(000) ) 622, 10 440 reflections in
h(-10/12), k(-15/16), l(-17/16), measured in the range 1.73°
e θ e 27.54°, completeness θmax ) 97.4%, 6694 independent
reflections, Rint ) 0.068, 5330 reflections with Fo > 4σ(Fo), 328
Crystal Data for 4:37 C24H52Ni4O8P4, Mr ) 827.38 g mol-1
,
yellow prism, size 0.04 × 0.04 × 0.03 mm3, cubic, space group
P4h3n, a ) 18.9491(5) Å, V ) 6804.0(3) Å3, T ) -90 °C, Z ) 6,
Fcalcd ) 1.212 g cm-3, µ(Mo KR) ) 18.07 cm-1, F(000) ) 2592,
4772 reflections in h(-24/24), k(-17/17), l(-16/16), measured
in the range 3.88° e θ e 27.47°, completeness θmax ) 99.2%,
2572 independent reflections, Rint ) 0.036, 2196 reflections
with Fo > 4σ(Fo), 104 parameters, 0 restraints, R1obs ) 0.041,
wR2obs ) 0.098, R1all ) 0.054, wR2all ) 0.104, GOOF ) 1.106,
parameters, 0 restraints, R1obs ) 0.053, wR2obs ) 0.147, R1all
0.065, wR2all ) 0.153, GOOF ) 1.079, largest difference peak
and hole 1.286/-0.797 e Å-3
)
.
Acknowledgment. We thank the Scholarship pro-
gram of the German Federal Environmental Foundation
(Deutsche Bundesstiftung Umwelt DBU) and the Deut-
sche Forschungsgemeinschaft for support of this re-
search.
(37) CCDC-246705 (1), CCDC-246706 (2), CCDC-246707 (4), CCDC-
246708 (6), CCDC-246709 (7), and CCDC-246710 (8) contain the
supplementary crystallographic data for this paper. These data can
be obtained free of charge via www.ccdc.cam.ac.uk/conts/
retrieving.html (or from the Cambridge Crystallographic Data Centre,
12 Union Road, Cambridge CB2 1EZ, UK.; fax: (+44) 1223-336-033;
or deposit@ccdc.cam.ac.uk).
Supporting Information Available: X-ray structural
information of complexes 1, 2, 4, 6, 7, and 8. This material is
available free for charge via the Internet at http://pubs.acs.org.
OM040111X