Synthesis and structural characterization of β-diketoiminate complexes containing three-coordinate zinc and copper atoms

Article abstract of DOI:10.1002/1099-0682(200208)2002:8<2156::AID-EJIC2156>3.0.CO;2-P

The reaction of the lithium β-diketoiminate complex (dipp)NacNacLi·OEt₂ {(dipp)NacNac = 2-[(2,6-diisopropyl- phenyl)amino]-4-[(2,6-diisopropylphenyl)imino]pent-2-enyl} with ZnCl₂ yielded the corresponding (dipp)NacNacZnCl (1) and (di

Full text of DOI:10.1002/1099-0682(200208)2002:8<2156::AID-EJIC2156>3.0.CO;2-P

FULL PAPER
Synthesis and Structural Characterization of β-Diketoiminate Complexes
Containing Three-Coordinate Zinc and Copper Atoms
Jörg Prust,[a] Holger Hohmeister,[a] Andreas Stasch,[a] Herbert W. Roesky,*[a] Jörg Magull,[a]
[a]
[a]
[a]
[a]
´
Eftichia Alexopoulos, Isabel Uson, Hans-G. Schmidt, and Mathias Noltemeyer
Dedicated to Professor Dieter Naumann on the occasion of his 60th birthday
Keywords: Acetylides / Copper / N ligands / Zinc
The reaction of the lithium β-diketoiminate complex
(dipp)NacNacLi·OEt2 {(dipp)NacNac = 2-[(2,6-diisopropyl-
phenyl)amino]-4-[(2,6-diisopropylphenyl)imino]pent-2-enyl}
with ZnCl2 yielded the corresponding (dipp)NacNacZnCl (1)
arrangement to the β-diketoiminate plane. The zinc atom in
2 is three-coordinated and that in 3 four-coordinated. Treat-
ment of (dipp)NacNacLi·OEt2 with CuI in diethyl ether
yielded {[Li(OEt2)][(dipp)NacNacCuI]}2 (4). In contrast to
and (dipp)NacNacZn(µ-Cl)2Li(OEt2)2 (1a). Treatment of 1 1a−3, compound 4 contains a dimetallic system. The core of
with LiCϵCPh and NaBH4 in diethyl ether gave (dipp)Nac-
NacZnCϵCPh (2) and (dipp)NacNacZn(µ-H)2BH2 (3). The
core element of compounds 1a−3 is a six-membered ZnN2C3
ring. The structure of 1a shows the β-diketoiminate back-
bone in a boat conformation with the tetrahedrally coordin-
ated metal centre in 1a at the prow and the opposing carbon
atom at the stern. The zinc atoms in 2 and 3 show a planar
compound 4 consists of two six-membered LiN2C3 rings and
one four-membered Cu2I2 ring. In addition to bonds to the
two iodine atoms, the three-coordinated copper atom has a
further bond to the γ-carbon atom of the six-membered
LiN2C3 ring.
( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany,
2002)
plexes exist as monomeric molecules with two-coordinate
zinc atoms.[9] However, the corresponding dialkylcopper
complexes, such as [LiCuMe2]2, exist as dimers.[10,11] Only
discrete R2CuϪ anions have been observed in crystals in
which the lithium cation is complexed by crown ethers.[12]
Recent reports have indicated increasing interest in zinc hy-
drides as reducing agents.[13Ϫ15] We have reported the syn-
thesis of [(dipp)NacNacZnH]2 by means of the reaction be-
tween [(dipp)NacNacZnF]2 and Et3SiH.[16]
Although the chemistry of organozinc complexes with
four-coordinate zinc atoms has been developed, the syn-
thesis of the corresponding acetylides is not well known.
Wright et al. synthesized the first zinc acetylide derivatives
in 1996,[17] and Dehnicke et al. have prepared a number of
zinc acetylide derivatives.[18,19] Monomeric compounds with
three-coordinate zinc are still quite rare; only a few ex-
amples have been reported in the literature.[20Ϫ27]
Introduction
Recent reports have indicated increasing interest in the β-
diketoiminate ligand, due to its sterically demanding and
chelating properties.[1,2] Vinamidines are useful for the sta-
bilization of low oxidation states of group-13 elements. Re-
cently, we reported the preparation of (dipp)NacNacAlI,
the first example of a monomeric AlI compound[3] stable at
room temperature. Power et al. described the synthesis of
the first compound containing a GaϪN double bond, by
using a β-diketoiminate ligand.[4] We have also reported on
the synthesis of a β-diketoiminate boranate complex of
magnesium, in which the magnesium centre is six-coordin-
ated and octahedral.[5]
While the first metals to have a prominent role in organic
synthesis were magnesium and lithium, several of the trans-
ition metals have also become very important.[6] Organo-
zinc[7] and organocopper[8] complexes are extensively used
in both organic and organometallic synthesis. In particular,
these complexes offer valuable alternatives to the corres-
ponding magnesium and lithium reagents. Dialkylzinc com-
Here we report on the formation of a monomeric zinc
acetylide complex with a three-coordinate zinc atom. We
used the bulky β-diketoiminate 2-[(2,6-diisopropylphenyl)-
amino]-4-[(2,6-diisopropylphenyl)imino]pent-2-enyl ligand
[(dipp)NacNac]. In summary, we prepared four new β-di-
ketoiminate zinc derivatives Ϫ (dipp)NacNacZnCl (1),
[a]
(dipp)NacNacZn(µ-Cl)2Li(OEt2)2
(1a),
(dipp)Nac-
Institut für Anorganische Chemie der Georg-August-
Universität, Göttingen
NacZnCϵCPh (2), and (dipp)NacNacZn(µ-H)2BH2 (3) Ϫ
and also one β-diketoiminate copper derivative,
{[Li(OEt2)][(dipp)NacNacCuI]}2 (4).
Tammannstrasse 4, 37077 Göttingen, Germany
Fax: (internat.) ϩ 49-(0)551/39-3373
E-mail: hroesky@gwdg.de
2156
 WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 1434Ϫ1948/02/0808Ϫ2156 $ 20.00ϩ.50/0 Eur. J. Inorg. Chem. 2002, 2156Ϫ2162

β-Diketoiminate Complexes Containing Three-Coordinate Zinc and Copper Atoms
FULL PAPER
Results and Discussion
Reactions with transition metal compounds are widely
used in organic chemistry, organocopper compounds being
important starting materials for new reactions in synthetic
chemistry.[5] Compound 4 was therefore prepared in high
yields (76%) by the addition of (dipp)NacNacLi·OEt2 to a
suspension of CuI in diethyl ether at Ϫ78 °C (Scheme 3).
Compounds 1 and 1a were prepared in high yield (92%)
by the addition of (dipp)NacNacLi·OEt2 to a ZnCl2 sus-
Scheme 1
pension in diethyl ether (Scheme 1). Compounds 2 and 3
were obtained by addition of LiCϵCPh and NaBH4, re-
spectively, to a solution of 1. LiCl and NaCl, respectively,
were eliminated, and the monomeric zinc complexes 2 and
3 were isolated in high yields (83% 2, 79% 3) (Scheme 2).
Scheme 3
Compound 4 was characterized by EI-MS spectrometry,
1H, 13C, and Li NMR and elemental analysis. Like com-
7
pounds 1Ϫ3, compound 4 is air- and moisture-sensitive.
The 1H NMR spectrum of 4 showed the typical resonances
of the β-diketoiminate unit, the resonances at δ ϭ 0.75 and
2.98 ppm corresponding with the protons of the coordin-
7
ated ether molecules. The 13C and Li NMR spectroscopic
data were consistent with the solid-state structure of 4. The
EI-MS showed a fragment of 4 minus one iodine atom
(m/z ϭ 1251 [M Ϫ I]ϩ).
Because of the similarity of compounds 1Ϫ7 to β-acetyl-
acetonate complexes, a few examples and their physical
properties are listed in Table 1 for comparison.
Scheme 2
Table 1. Physical data of compounds 1Ϫ9; acac ϭ acetylacetonate,
tmtch ϭ 3,3,6,6-tetramethyl-1-thia-4-cycloheptyne, Tp* ϭ hy-
drotris(3-cumyl-5-methylpyrazolyl)borate
Compounds 1, 2, and 3 were characterized by EI-MS
spectrometry, 1H and 13C NMR and elemental analysis. All
M.p. [°C]
1H NMR of
γ-CH (δ [ppm])
1
compounds are moisture- and air-sensitive. The H NMR
spectra of 1, 2, and 3 showed the typical resonances of the
β-diketoiminate unit, with two non-equivalent resonances
for the methyl groups of the isopropyl substituents due to
the hindered rotation about the ArϪN bonds, as observed
for related metal systems.[1Ϫ3,28] The 1H NMR spectro-
scopic data were consistent with the solid-state structures
of 2 and 3. Single crystals suitable for X-ray structural ana-
(dipp)NacNacZnCl (1)
205
154
4.88
5.00
(dipp)NacNacZnCϵCPh (2)
(dipp)NacNacZn(µ-H)2BH2 (3)
[{Et2O)Li}{(dipp)NacNacCuI}]2 (4)
(dipp)NacNacZnPh (5)[2]
182Ϫ186 4.71
165
155
165
4.24
5.04
4.85
(dipp)NacNacMgiPr·Et2O (6)[5]
(dipp)NacNacAl (7)[3]
Ͼ 150 (dec.) 5.18
183
116
(Tp*)Zn(cumoylacetonate) (8)[29]
(acac)Cu(tmtch) (9)[30]
5.43
5.37
1
lysis were only obtained for 1a, but the H NMR spectrum
was not consistent with the solid-state structure, with no
resonances assignable to protons of the diethyl ether mole-
cules being observed. From the predominance of 1 in the
The compounds 8 and 9 used for the comparison have
NMR and EI-MS spectra (m/z ϭ 516 [Mϩ]) 1a is obviously coordination numbers at their metal centres of three for 8
a by-product that crystallises more rapidly than the main and of five for 9. It can be seen that the melting points of
product. The EI-MS spectra of 2 and 3, however, showed the β-acetylacetonate complexes (8, 9) range from 116 to
the molecular fragments for 2 (m/z ϭ 582 [Mϩ]) and for 3 183 °C, while those of compounds 1Ϫ4 ranged from 154 to
(m/z ϭ 482 [M Ϫ BH3]ϩ), respectively.
205 °C. The resonances for γ-CH in 8 and 9 were shifted
Eur. J. Inorg. Chem. 2002, 2156Ϫ2162
2157

H. W. Roesky et al.
FULL PAPER
downfield [δ ϭ 5.43 (8), 5.37 (9) ppm] relative to the β-
diketoiminate compounds 1Ϫ7.
Molecular Structures
The central core of compounds 1aϪ3 is a (dipp)Nac-
NacZn unit. The β-diketoiminate ligand acts as a chelating
ligand through its two nitrogen atoms, forming a six-mem-
bered ring with the zinc atom. The six-membered ZnN2C3
ring in 1a is not planar, but displays a boat conformation
with the metal atom at the prow and the opposite carbon
atom at the stern, whereas the ZnN2C3 rings in 2 and 3 are
planar. This deviation from planarity is imposed by the
metal centre, as the planar arrangement implies more dis-
tortion of its coordination sphere. Nevertheless, the π-elec-
trons of the β-diketoiminate ligand are delocalised, since
the C(1)ϪC(2), C(2)ϪC(3), C(1)ϪN(1), and C(3)ϪN(2)
bond lengths in each compound are equal within experi-
mental errors and correspond to those in conjugated sys-
tems.[26] Moreover, the two NϪZn bond lengths are equal
˚
as well. The ZnϪN distances {1a: 1.979(2) and 1.982(2) A;
Figure 1. Crystal structure of 1a (hydrogen atoms are omitted for
clarity)
˚
2 [(C7H8)0.5]: 1.941(2) and 1.929(2) A; 3: 1.917(6) and
˚
1.911(6) A} are shorter than those in comparable ZnϪN
derivatives.[28,32Ϫ34] The NϪZnϪN angles are 97.8° in com-
pound 1a, 98.8° in 2 and 101.9° in 3.
˚
Table 2. Selected bond lengths [A] and angles [°] of 1a
The tetrahedral coordination sphere of the zinc atom is
completed in compound 1a by two chlorine atoms and in
compound 3 by two hydrogen atoms, whereas the zinc atom
in compound 2 adopts a trigonal-planar environment
through an additional bond to one CϵCPh moiety.
Zn(1)ϪCl(1)
Zn(1)ϪCl(2)
Zn(1)ϪN(1)
Zn(1)ϪN(2)
N(1)ϪC(1)
N(2)ϪC(3)
C(1)ϪC(2)
C(2)ϪC(3)
Cl(1)ϪLi(1)
Cl(2)ϪLi(1)
2.2858(8)
2.3144(8)
1.979(2)
1.982(2)
1.324(3)
1.326(3)
1.398(4)
1.409(4)
2.371(5)
2.384(5)
N(1)ϪZn(1)ϪN(2)
C(1)ϪN(1)ϪZn(1)
C(3)ϪN(2)ϪZn(1)
N(1)ϪC(1)ϪC(2)
C(3)ϪC(2)ϪC(1)
N(2)ϪC(3)ϪC(2)
N(1)ϪZn(1)ϪCl(1)
N(2)ϪZn(1)ϪCl(1)
N(1)ϪZn(1)ϪCl(2)
N(2)ϪZn(1)ϪCl(2)
Zn(1)ϪCl(1)ϪLi(1)
Zn(1)ϪCl(2)ϪLi(1)
97.88(8)
120.42(16)
19.75(17)
124.0(2)
130.1(2)
124.3(2)
115.20(6)
117.82(6)
116.71(6)
113.02(6)
84.52(11)
83.63(12)
The central core of 4 is made up of two (dipp)NacNacLi
units. As in 1aϪ3, the β-diketoiminate ligand acts as a che-
lating ligand through its two nitrogen atoms, forming a six-
membered ring with the lithium atom. The LiN2C3 rings in
4 are not planar, but display boat conformations with the
metal atom at the prow and the opposite γ-carbon atom at
the stern. Surprisingly, the copper atom forms a bond to the
γ-carbon atom of the β-diketoiminate ligand. In contrast,
Tolman et al. recently reported the preparation of a cop-
per(I) compound with the β-diketoiminate ligand in which
the copper formed a six-membered CuN2C3 ring.[35] A pos-
sible explanation for this different behaviour might be that
the soft CuI prefers coordination with the soft carbon atom
while the harder CuII prefers coordination with the harder
Molecular Structure of 2
Compound 2 crystallises in the monoclinic space group
P21/n with one molecule in the asymmetric unit. Besides the
two nitrogen atoms of the (dipp)NacNac ligand, the zinc
atom coordinates to one phenylacetylide group, a trigonal
coordination sphere of the zinc atom thus being formed
(Figure 2). Furthermore, the ZnϪCϵC backbone deviates
from linearity [ZnϪC(30)ϪC(31): 168.18(19)°]. This devi-
ation from linearity has been reported for corresponding
transition metal complexes[32Ϫ34] and also found in alumi-
nium compounds.[38] Selected bond lengths and angles for
2 are given in Table 3.
˚
nitrogen atoms. The CuϪC bond length of 2.089(6) A is
similar to those found in the literature.[36,37] The trigonal
environment of the copper atom is completed by two iodine
atoms. The copper atoms form a four-membered Cu2I2 ring
with the two iodine atoms. The C(1)ϪC(2) and C(2)ϪC(3)
˚
bond lengths [1.443(8) and 1.455(8) A] correspond to CϪC
single bonds, whereas the CϪN bond lengths [1.295(8) and
˚
1.299(8) A] are in the range of CϪN double bonds.
The crystallographic data for 1a, 2, 3, and 4 are summar-
ized in Table 6.
Molecular Structure of 3
Molecular Structure of 1a
Compound 1a crystallises in the monoclinic space group
Compound 3 crystallises in the monoclinic space group
P21/n with one molecule in the asymmetric unit (Figure 1). P21/n (Figure 3). The BϪH(b1 and b2) bond lengths are
˚
Selected bond lengths and angles for 1 are given in Table 2. nearly equal [1.211(8) and 1.214(8) A]. Compound 3 is thus
2158
Eur. J. Inorg. Chem. 2002, 2156Ϫ2162

β-Diketoiminate Complexes Containing Three-Coordinate Zinc and Copper Atoms
FULL PAPER
a boranate complex but not an adduct of BH3. The ter-
minal BϪH bond lengths correspond to those found in the
literature.[13Ϫ15] Selected bond lengths and angles for 3 are
given in Table 4.
Molecular Structure of 4
Compound 4 crystallises in the monoclinic space group
P21/n with half a molecule in the unit cell (Figure 4). Se-
lected bond lengths and angles for 4 are given in Table 5.
˚
Table 4. Selected bond lengths [A] and angles[°] of 3
Zn(1)ϪN(1)
Zn(1)ϪN(2)
Zn(1)ϪH(b1)
Zn(1)ϪH(b2)
B(1)ϪH(b1)
B(1)ϪH(b2)
B(1)ϪH(b3)
B(1)ϪH(b4)
N(1)ϪC(1)
N(2)ϪC(3)
C(1)ϪC(2)
1.917(6)
1.911(6)
1.754(9)
1.744(9)
1.211(8)
1.214(8)
1.059(8)
1.052(8)
1.333(4)
1.334(4)
1.394(3)
1.404(3)
N(1)ϪZn(1)ϪN(2)
B(1)ϪH(b1)ϪZn(1)
B(1)ϪH(b2)ϪZn(1)
H(b1)ϪZn(1)ϪN(1)
H(b1)ϪZn(1)ϪN(2)
H(b2)ϪZn(1)ϪN(1)
H(b2)ϪZn(1)ϪN(2)
Zn(1)ϪN(1)ϪC(1)
Zn(1)ϪN(1)ϪC(3)
N(1)ϪC(1)ϪC(2)
C(1)ϪC(2)ϪC(3)
101.96(3)
91.08(7)
91.47(7)
120.91(12)
123.50(12)
119.80(12)
121.03(12)
119.48(6)
119.78(6)
124.21(4)
130.66(4)
Figure 2. Crystal structure of 2 (hydrogen atoms are omitted for
clarity)
C(2)ϪC(3)
˚
Table 3. Selected bond lengths [A] and angles [°] of 2
Zn(1)ϪC(30)
Zn(1)ϪN(1)
Zn(1)ϪN(2)
N(1)ϪC(1)
N(2)ϪC(3)
C(1)ϪC(2)
C(2)ϪC(3)
C(30)ϪC(31)
C(31)ϪC(32)
1.906(2)
1.941(2)
1.929(2)
1.333(3)
1.335(3)
1.403(3)
1.406(3)
1.207(3)
1.439(3)
Zn(1)ϪC(30)ϪC(31)
C(30)ϪC(31)ϪC(32)
N(1)ϪZn(1)ϪN(2)
N(1)ϪZn(1)ϪC(30)
N(2)ϪZn(1)ϪC(30)
N(1)ϪC(1)ϪC(2)
N(2)ϪC(3)ϪC(2)
C(3)ϪC(2)ϪC(1)
168.18(19)
177.1(2)
98.85(7)
124.14(8)
137.01(8)
123.55(18)
123.87(19)
129.56(19)
Figure 4. Crystal structure of 4 (hydrogen atoms are omitted for
clarity)
˚
Table 5. Selected bond lengths [A] and angles [°] of 4
Cu(1)ϪC(2)
Cu(1)ϪI(1)
N(1)ϪLi(1)
N(2)ϪLi[(1)
N(1)ϪC(1)
N(2)ϪC(3)
C(1)ϪC(2)
C(2)ϪC(3)
2.089(6)
2.5711(2)
1.969(10)
1.973(11)
1.295(8)
1.299(8)
1.443(8)
1.455(8)
C(2)ϪCu(1)ϪI(1)
C(1)ϪC(2)ϪCu(1)
C(3)ϪC(2)ϪCu(1)
C(1)ϪN(1)ϪLi(1)
C(3)ϪN(2)ϪLi(1)
C(3)ϪN(2)ϪLi(1)
N(1)ϪC(3)ϪC(2)
N(2)ϪC(3)ϪC(2)
117.4(2)
91.8(3)
110.8(4)
117.5(5)
117.5(5)
114.9(5)
123.3(5)
124.4(5)
Figure 3. Crystal structure of 3 (hydrogen atoms are omitted for
clarity)
Eur. J. Inorg. Chem. 2002, 2156Ϫ2162
2159

H. W. Roesky et al.
FULL PAPER
[d, J ϭ 6.8 Hz, 12 H, CH(CH3)2], 1.18 [d, J ϭ 6.8 Hz, 12 H,
CH(CH3)2], 1.20 [d, J ϭ 6.8 Hz, 12 H, CH(CH3)2], 1.70 (s, 6 H,
CH3), 1.75 (s, 6 H, CH3), 3.02 (sept, J ϭ 6.8 Hz, 3.07 [sept, J ϭ
6.8 Hz, 4 H, CH(CH3)2], 4.87 (s, 1 H, CH), 4.89 (s, 1 H, CH),
7.12 (m, 6 H, ArH) ppm. 13C NMR (125 MHz, C6D6): δ ϭ 23.3
[NC(CH3)], 25.4 [CH(CH3)2], 28.8 [CH(CH3)2], 94.2 (γ-C), 123.8
(ArC), 125.2 (ArC), 141.2 (ArC), 142.3 (ArC), 165.4 (NC) ppm.
MS (EI): m/z (%) ϭ 481 (21) [M Ϫ Cl]ϩ, 516 (100) [Mϩ].
C29H41ClN2Zn (518.49): calcd. C 67.18, H 7.97, N 5.40; found C
Conclusions
The sterically demanding β-diketoiminate ligand
(dipp)NacNac facilitates the stabilization of compounds
with low-coordination sites at the metal centre. We have
synthesized three zinc β-diketoiminate complexes and one
copper β-diketoiminate complex with novel structural mo-
tifs generated through substitution of the chlorine and iod-
ine atom, respectively. We are at present investigating these 67.0, H 7.6, N 5.3. Molecular mass (cryoscopic in THF in g/mol):
calcd. 518.49; found 505. Only single crystals of 1a were suitable
for X-ray structural analysis.
compounds as alternatives for Grignard reagents in or-
ganic syntheses.
(dipp)NacNacZnCϵCPh (2): A solution of LiCϵCPh (2.34 mL of
a 1.0  solution in THF, 2.34 mmol) was slowly added at Ϫ78 °C
to a stirred solution of (dipp)NacNacZnCl (1.21 g, 2.34 mmol) in
Et2O (20 mL). The reaction mixture was stirred for an additional
3 h and allowed to warm to room temperature. The residue was
filtered and the solution was concentrated to 10 mL under reduced
pressure. Storage at Ϫ24 °C afforded colourless crystals of 2: Yield
1.13 g (1.94 mmol), 83%. M.p. 154 °C. 1H NMR (500 MHz, C6D6):
δ ϭ 1.17 [d, J ϭ 6.8 Hz, 12 H, CH(CH3)2], 1.40 [d, J ϭ 6.8 Hz,12
H, CH(CH3)2], 1.67 (s, 6 H, CH3), 3.19 [sept, J ϭ 6.8 Hz, 4 H,
CH(CH3)2], 5.00 (s, 1 H, CH), 6.72Ϫ7.28 (m, 11 H, ArH) ppm.
Experimental Section
General: All reactions were performed by standard Schlenk and
dry-box techniques. Solvents were appropriately dried and distilled
under dinitrogen prior to use. All NMR spectra were recorded in
5-mm tubes with dry degassed [D6]benzene as a solvent, referenced
externally to SiMe4. Elemental analyses were performed by the An-
alytisches Chemisches Laboratorium des Instituts für Anorgani-
sche
Chemie,
Göttingen,
and
(dipp)NacNacH
and
(dipp)NacNacLi·OEt2 were prepared by literature procedures.[3]
13C NMR (125 MHz, C6D6):
δ ϭ 20.5 [NC(CH3)], 23.7
[CH(CH3)2], 24.5 CH(CH3)2, 28.3 [CH(CH3)2], 77.7 (CϵC), 83.8
(CϵC), 94.3 (γ-C), 123.3 (ArC), 123.5 (ArC), 124.5 (ArC), 125.1
(ArC), 128.2 (ArC), 139.2 (ArC), 142.6 (ArC), 161.9 (NC) ppm.
MS (EI): m/z (%) ϭ 202 (100) [DippNCCH3], 481 (29) [M Ϫ
CϵCPh]ϩ, 582 (59) [Mϩ]. C37H46N2Zn (584.16): calcd. C 76.08, H
7.94, N 4.80; found C 75.5, H 7.94, N 4.6.
(dipp)NacNacZnCl (1): solution of (dipp)NacNacLi·OEt2
A
(3.11 g, 1.55 mmol) in Et2O (20 mL) was slowly added at Ϫ78 °C
to a suspension of ZnCl2 (420 mg, 1.55 mmol) in Et2O (20 mL).
The mixture was allowed to warm to room temperature and then
stirred for an additional 3 h and filtered. The solution was reduced
in vacuo to 10 mL and stored at Ϫ24 °C to yield 1 and 1a
[(dipp)NacNacZn(µ-Cl)2LiOEt)2]2 as colourless crystalline solids
(dipp)NacNacZn(µ-H)2BH2 (3): A solution of (dipp)NacNacZnCl
after 2 d. Data for 1: Yield 1.48 g, 92%. M.p. 205 °C. 1H NMR (1.59 g, 3.10 mmol) in Et2O (20 mL) was slowly added at Ϫ78 °C
(500 MHz, C6D6): δ ϭ 1.15 [d, J ϭ 6.8 Hz, 12 H, CH(CH3)2], 1.16 to a suspension of NaBH4 (0.117 g, 3.10 mmol) in Et2O (10 mL).
Table 6. Crystallographic data of 1a, 2, 3, and 4
1a
2·(C7H8)0.5
3
4
Empirical formula
Formula mass
C37H61Cl2LiN2O2Zn
709.09
203
C40.5H54N2Zn
634.23
133(2)
0.71073
monoclinic
C2/c
a ϭ 18.0736(6) A
b ϭ 19.2773(9) A
c ϭ 21.1298(8) A
C29H45BN2Zn
497.85
133(2)
0.71073
monoclinic
P21/n
a ϭ 12.344(3) A
b ϭ 17.605(4) A
c ϭ 13.884(3) A
C66H102Cu2I2Li2N4O2
1378.28
203(2)
Temperature [K]
˚
Wavelength [A]
0.71073
0.71073
Crystal system
Space group
Unit cell dimensions
monoclinic
P21/n
a ϭ 12.0841(17) A
b ϭ 21.2125(5) A
c ϭ 15.896(3) A
monoclinic
P21/n
a ϭ 10.622(3) A
˚
˚
˚
˚
˚
˚
˚
˚
˚
˚
b ϭ 26.509(16) A
c ϭ 12.542(3) A
˚
˚
β ϭ 99.961(16)°
β ϭ 104.969°
β ϭ 104.93(3)
2914.4(10)
4
1.135
0.860
β ϭ 107.77(2)°
3363.0(23)
2
1.361
1.593
3
˚
Volume [A ]
Z
6031(13)
7112.0(5)
4
8
Density (calculated) [Mg/m3]
Absorption coefficient [mmϪ1
F(000)
1.168
0.772
1520
1.185
0.720
2728
]
1072
1424
Crystal size [mm]
0.8 ϫ 0.6 ϫ 0.3
3.55 to 25.00°
9210
7073 [Rint ϭ 0.0547]
7073/0/420
1.039
R1 ϭ 0.0488
wR2 ϭ 0.1380
R1 ϭ 0.0551
wR2 ϭ 0.1380
0.979 and Ϫ1.066
0.4 ϫ 0.3 ϫ 0.4
1.57 to 24.79°
53140
6097 [Rint ϭ 0.0489]
6097/0/417
1.077
R1 ϭ0.0344
wR2 ϭ 0.1091
R1 ϭ 0.0380
wR2 ϭ 0.1108
1.127 and Ϫ0.346
0.2 ϫ 0.2 ϫ 0.1
2.06 to 24.44°
35772
4800 [Rint ϭ 0.1107]
4800/3/324
1.027
R1 ϭ 0.0446
wR2 ϭ 0.1097
R1 ϭ 0.0578
wR2 ϭ 0.1189
0.288 and Ϫ0.448
0.8 ϫ 0.6 ϫ 0.3
3.52 to 24.99°
5885
5874 [Rint ϭ 0.0474]
5868/0/364
1.166
R1 ϭ 0.0594
WR2 ϭ 0.1682
R1 ϭ 0.0652
WR2 ϭ 0.1762
0.954 to Ϫ1.089
θ range for data collection
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I Ͼ 2σ(I)]
R indices (all data)
Ϫ3
˚
Largest diff. peak and hole [e·A
]
2160
Eur. J. Inorg. Chem. 2002, 2156Ϫ2162

β-Diketoiminate Complexes Containing Three-Coordinate Zinc and Copper Atoms
FULL PAPER
´
I. Uson, D. Böhler, T. Schuchardt, Organometallics 2001, 20,
The mixture was allowed to warm to room temperature and then
stirred for an additional 12 h and filtered. The solution was reduced
to 5 mL in vacuo and stored at Ϫ24 °C to yield colourless crystals
of 3: Yield 1.21 g, 79%. M.p. 182Ϫ186 °C. 1H NMR (500 MHz,
C6D6): δ ϭ 1.15 [d, J ϭ 6.8 Hz, 12 H, CH(CH3)2], 1.19 [d, J ϭ
6.8 Hz, 12 H, CH(CH3)2], 1.59 (s, 6 H CH3), 3.48 [sept, J ϭ 6.8 Hz,
4 H, CH(CH3)2], 4.71 (s, 1 H, CH), 7.12Ϫ7.19 (m, 6 H, ArH) ppm.
3825Ϫ3828.
[3]
[4]
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2032Ϫ2037.
13C NMR (125 MHz, C6D6):
δ ϭ 23.1 [NC(CH3)], 24.7
[CH(CH3)2], 25.2 [CH(CH3)2], 28.6 [CH(CH3)2], 97.9 (γ-C), 124.8
(ArC), 125.1 (ArC), 142.1 (ArC), 168.1 (NC) ppm. MS (EI): m/z
(%) ϭ 417 (100) [M Ϫ ZnBH4]ϩ, 482 (43) [M Ϫ BH3]ϩ.
C29H45BN2Zn (497.85): calcd. C 69.96, H 9.12, N 5.63; found C
68.2, H 7.9, N 4.8.
´
[6]
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[{Et2O)Li}{(dipp)NacNacCuI}]2
(4):
A
solution
of
(dipp)NacNacLi·OEt2 (1.18 g, 2.28 mmol) in Et2O (20 mL) was
slowly added at Ϫ78 °C to a suspension of CuI (434 mg,
2.28 mmol) in Et2O (20 mL). The mixture was allowed to warm to
room temperature and then stirred for an additional 24 h and fil-
tered. The solution was concentrated to 5 mL under reduced pres-
sure. Storage at Ϫ24 °C afforded colourless crystals of 4. Yield
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
1
1.19 g, 76%. M.p. 165 °C (decomp.). H NMR (500 MHz, C6D6):
δ ϭ 0.75 (t, J ϭ 6.8 Hz, 12 H, OCH2CH3), 1.12 [d, J ϭ 6.8 Hz, 24
H, CH(CH3)2], 1.21 [d, J ϭ 6.8 Hz, 24 H, CH(CH3)2], 1.78 (s, 12
H, CH3), 2.98 (q, J ϭ 6.8 Hz, 8 H, OCH2CH3), 3.13 [sept, J ϭ
6.8 Hz, 4 H, CH(CH3)2], 4.24 (s, 2 H, CH), 7.08Ϫ7.14(m, 12 H,
7
ArH) ppm. Li NMR (97 MHz, C6D6): δ ϭ 0.64 ppm. 13C NMR
(C6D6): δ ϭ 14.6 (CH3CH2O), 23.3 [NC(CH)3], 24.0 [CH(CH3)2],
24.4 [CH(CH3)2], 28.1 [CH(CH3)2], 64.3 (γ-C), 124.1 (ArC), 125.3
(ArC), 141.9 (ArC), 144.8 (ArC), 163.5 (NC) ppm. MS (EI): m/z
(%) ϭ 202 (100) [DippNCCH3], 417 (30) [(dipp)2NacNac], 1251
(40) [M Ϫ I]ϩ. C66H102Cu2I2Li2N4O2 (1378.28): calcd. C 57.51, H
7.46, N 4.06; found C 58.7, H 8.5, N 5.2.
[18]
[19]
[20]
[21]
[22]
[23]
[24]
[25]
[26]
[27]
Crystal Structure Determination: All crystals were mounted on
glass fibres in a rapidly cooled perfluoropolyether.[39] Diffraction
data for 1a and 4 were collected with a Stoe-Siemens-Huber four-
circle diffractometer at 203(2) K, with graphite-monochromated
˚
Mo-Kα radiation (λ ϭ 0.71073 A), while diffraction data for 2 and
3 were collected with a Stoe IPDS-II at 133(2) K, again with graph-
˚
ite-monochromated Mo-Kα radiation (λ ϭ 0.71073 A). The struc-
tures were solved by direct methods with SHELXS-97 and refined
against F2 on all data by full-matrix, least squares with SHELXS-
97.[40,41] All non-hydrogen atoms were refined anisotropically. The
hydrogen atoms were included in the model at geometrically calcu-
lated positions and refined with a riding model if not otherwise
stated (Table 6). Atomic coordinates, thermal parameters, bond
lengths and angles: CCDC-175030 (1a), -175031 (2), 175033-(3),
and -175032 (4) contain the supplementary crystallographic data
for this paper. These data can be obtained free of charge at
www.ccdc.cam.ac.uk/conts/retrieving.html or from the Cambridge
Crystallographic Data Centre, 12, Union Road, Cambridge
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CB2 1EZ, UK [Fax: (internat.)
deposit@ccdc.cam.ac.uk].
ϩ 44-1223/336-033; E-mail:
[29]
[30]
[31]
Acknowledgments
The financial support of the Deutsche Forschungsgemeinschaft
and the Göttinger Akademie der Wissenschaften is very gratefully
acknowledged.
[32]
[33]
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Y. Q. Ding, H. W. Roesky, M. Noltemeyer, H.-G. Schmidt, P.
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Eur. J. Inorg. Chem. 2002, 2156Ϫ2162
2161

H. W. Roesky et al.
FULL PAPER
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R. Beckhaus, M. Wagner, V. V. Burlakov, W. Baumann, N. Peu-
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[37]
Received January 10, 2002
[I02012]
2162
Eur. J. Inorg. Chem. 2002, 2156Ϫ2162