Zinc complexes of aldehydes and ketones, 2 zinc-aldehyde complexes with weakly coordinating anions

Article abstract of DOI:10.1002/(sici)1099-0682(199901)1999:1<117::aid-ejic117>3.0.co;2-0

Zinc salts of low or zero water content were obtained from the hexahydrates of zinc nitrate, zinc perchlorate, and zinc tetrafluoroborate by dehydration with triethoxymethane or by solvation with acetonitrile or nitromethane. The compounds incorporated al

Full text of DOI:10.1002/(sici)1099-0682(199901)1999:1<117::aid-ejic117>3.0.co;2-0

FULL PAPER
Zinc Complexes of Aldehydes and Ketones, 2[°]
Zinc-Aldehyde Complexes with Weakly Coordinating Anions
Bodo Müller[a] and Heinrich Vahrenkamp*[a]
Keywords: Zinc / Aldehyde ligands / Weakly coordinating anions / Structural chemistry
Zinc salts of low or zero water content were obtained from
the hexahydrates of zinc nitrate, zinc perchlorate, and zinc
tetrafluoroborate by dehydration with triethoxymethane or
by solvation with acetonitrile or nitromethane. The
compounds incorporated aldehydes as ligands when treated
with an excess of the aromatic aldehydes benzaldehyde,
mesitylaldehyde, 2-chlorobenzaldehyde, and 4-fluoro-
benzaldehyde. Eighteen zinc-aldehyde complexes were
isolated and identified by crystal structure determinations.
All contain octahedral zinc to which 2, 3, 4, 5, or 6 aldehyde
ligands are bound. Water, ethanol, and acetonitrile molecules
–
–
act as coligands. Of the anions employed, BF4 and SbCl6
–
were found to be only noncoordinating and NO3 only
coordinating, whereas complexes with one or two
perchlorate ligands were obtained in addition to
perchlorate salts.
It is widely known that countless reactions of organic were characterized by structure determinations. Likewise,
carbonyl compounds (esters, amides, aldehydes, ketones, for all other metals the number of well-characterized alde-
etc.) can be catalyzed by metal salts or complexes. Zinc hyde complexes is small, and the level of information is
species play a dominant role in this context for preparative noteworthy only for complexes of salicylic aldehyde and its
organic chemistry[2] as well as for enzyme-catalyzed trans- derivatives as well as for organometallic complexes of η2
formations[3]. The basic function of the metal ion in these (side-on)-coordinated simple aldehydes[4]. A search of the
reactions is its attachment to the carbonyl oxygen to induce Cambridge Crystallographic Data File has yielded just six
Lewis-acidic activation. However, since carbonyl com- further structures of classical metal complexes with mono-
pounds are only weak donors and since the important reac- dentate O-coordinated aldehyde ligands.
tions are catalytic, metal complexes of organic carbonyl
Our systematic approach to the chemistry of zinc alde-
compounds are rarely isolated. Therefore, in sharp contrast hyde complexes followed four lines: (a) monodentate plain
to the many mechanistic proposals involving metal acti- aldehydes and zinc salts of weakly coordinating anions; (b)
vation of the carbonyl function, the coordination chemistry monodentate plain aldehydes and zinc halides; (c) chelating
of this function is rather underdeveloped[4]
.
aldehydes derived from nitrogen heterocycles; (d) aldehyde
We became interested in zinc coordination of CO-con- complexes of zinc thiolates. The aims of this study were: (a)
taining species during our model studies and mechanistic to obtain as many different compound types as possible; (b)
interpretations of zinc enzyme-catalyzed hydrolyses of es- to confirm their composition and constitution by structure
ters, amides, and CO2 by ZnϪOH complexes[5]. Our atten- determinations; (c) to elucidate the donor qualities of the
tion focused on aldehydes and alkoxides as ligands when aldehydes as compared to those of competing ligands like
trying to reproduce the biological function of zinc-contain- water and anions; (d) to find relationships between the
ing alcohol dehydrogenase[6] by stepwise reactions with zinc complex properties and catalytic phenomena; (e) to model
complexes[7]. We therefore set out to undertake a compre- the structure and function of the active site of horse liver
hensive study of zinc complexation by aldehydes, which led alcohol dehydrogenase. We have published a short com-
to the results presented in this and the two succeeding[8][9] munication describing the initial stages of this work[1]. This
papers.
manuscript is the first in a series of full papers describing
The literature on metal complexation of plain aldehydes zinc complexes with predominant or exclusive aldehyde co-
contains a few papers describing zinc complexes, i.e. hexaal- ordination.
dehyde solvates of zinc salts[10][11], the benzaldehyde adduct
of zinc chloride[12], mono- and bis-aldehyde adducts of zinc
chalcogenolates[13], chelate complexes of pyridine-2-carbal-
Preparations and Structures
dehyde[14Ϫ16], and two zinc porphyrin complexes with η1-
coordinated benzaldehyde[17][18]. Of these examples only the
latter two[17][18] and the Zn(SeR)2(anisaldehyde) dimer[13]
It was clear after our preliminary studies[1] that water,
donor solvents, and anions with donor properties, like hal-
ides, are better ligands for the zinc ion than aldehydes. Fur-
thermore, aliphatic aldehydes were preferentially con-
densed, polymerized, or underwent disproportionation to
carboxylic esters rather than being incorporated into stable
[°]
Part 1: Ref.[1]
[a]
Institut für Anorganische und Analytische Chemie der Universi-
tät Freiburg,
Albertstr. 21, D-79104 Freiburg, Germany
Eur. J. Inorg. Chem. 1999, 117Ϫ127
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1999
1434Ϫ1948/99/0101Ϫ0117 $ 17.50ϩ.50/0
117

B. Müller, H. Vahrenkamp
FULL PAPER
complexes. This fact dictated the working procedures and
the choice of aldehydes. All reactions were carried out in
water-free nonpolar solvents containing high concen-
trations of the aldehydes or using the neat aldehydes as sol-
vents. The water content of the zinc salts was controlled
by using triethoxymethane as a dehydrating agent[19] or by
starting from water-free zinc hexachloroantimonate sol-
vates[20][21]
. Thus the starting zinc compounds were
[Zn(H2O)6]X2 (X ϭ ClO4, BF4, NO3), [Zn(CH3CN)6]-
(SbCl6)2, and [Zn(CH3NO2)6](SbCl6)2. These compounds
were treated with various aromatic aldehydes of which the
following allowed the isolation of pure complexes:
˚
Figure 1. Zinc coordination in 1 and 2. Bond lengths [A] and angles
[°] for 1/2: ZnϪO1 2.125(1)/2.129(2), ZnϪO2 2.069(1)/2.052(2),
ZnϪO3 2.053(1)/2.075(2), O1ϪC1 1.227(2)/1.227(3), ZnϪO1ϪC1
135.2(1)/135.5(2), OϪCϪC 126.0(1)/125.4(2).
Diaqua-tetraaldehyde complexes were again obtained
only from Zn(ClO4)2, Zn(BF4)2 and mesitylaldehyde. Of
these complexes, compound 3 again contains two aldehyde
molecules in the second coordination sphere, while 4 has
only zinc-coordinated aldehyde. The structure determi-
nations showed that zinc is again trans-configured in both
compounds (Figure 2). In these cases the ZnϪO(aldehyde)
and ZnϪO(water) bond lengths are spread irregularly over
The hydrated zinc salt was always first dissolved in tri-
ethoxymethane before the reaction was started. For each
water molecule to be removed, one equivalent of triethoxy-
methane was applied, plus one additional equivalent for
completion of the dehydration. After drying the (partially)
dehydrated zinc salt in vacuo it was treated with a large
excess of the aldehyde. The resulting clear solutions were
diluted with petroleum ether, which caused the aldehyde-
containing zinc salts to precipitate. This process worked in
all cases. However, the precipitates were never crystalline
(e.g. oily) or pure when the precipitation was performed by
adding petroleum ether. It was therefore essential to prepare
the products by slow crystallization. This was achieved by
layering the neat or dichloromethane-diluted aldehyde solu-
tions with petroleum ether and keeping the mixture in a
vibration-free place at or slightly below room temperature.
In this way all products that could be obtained pure were
crystalline and immediately suitable for X-ray crystallogra-
phy. Due to their extremely hygroscopic nature, all handling
of the compounds required the rigorous exclusion of water.
Tetraaqua-bisaldehyde complexes were obtained from
zinc perchlorate and tetrafluoroborate with mesitylalde-
hyde. Compounds 1 and 2 were originally believed to be
tetraaldehyde complexes, and only the structure determi-
nations revealed that they contain, in the solid state, two
non-coordinating aldehyde molecules that are linked by hy-
drogen bridges to water ligands.
˚
their range from 2.04 to 2.13 A.
[Zn(MA)4(H2O)2](ClO4)2 • 2 MA
[Zn(MA)4(H2O)2](BF4)2
3
4
Figure 2. Zinc coordination in [Zn(MA)4(H2O)2](ClO4)2 • 2 MA
˚
(3) and [Zn(MA)4(H2O)2](BF4)2 (4). Bond lengths [A] and angles
[°] for 3/4: ZnϪO1 2.061(3)/2.128(1), ZnϪO2 2.086(2)/2.102(1),
ZnϪO3 2.109(2)/2.036(1), O1ϪC1 1.225(3)/1.233(2), O2ϪC2
1.226(4)/1.225(2), ZnϪO1ϪC1 130.7(2)/122.6(1), ZnϪO2ϪC2
132.7(2)/129.3(1),
125.1(3)/125.1(2).
O1ϪCϪC
125.9(3)/126.5(2),
O2ϪCϪC
In order to make these partially solvated zinc salts avail-
able for a wider range of aldehydes, two equivalents of etha-
nol were added to solutions of the bis-hydrates in various
aldehydes. However, in only two cases did this lead to pure
compounds, and these products were 5 and 6. In all other
cases the precipitates were non-crystalline and non-uni-
form. The structure determinations (Figure 3) showed that
[Zn(MA)2(H2O)4]X2 • 2 MA
1: X ϭ ClO4, 2: X ϭ BF4
Figure 1 shows the coordination pattern of 1 and 2. In the two aldehyde, alcohol, and water ligands are each
both cases the two aldehyde ligands are in trans positions, bound to zinc in an all-trans fashion. There is no note-
and the ZnϪO(aldehyde) bonds are longer than the worthy distinction between the ZnϪO bond lengths for the
ZnϪO(water) bonds.
aldehyde, alcohol, or water ligands.
118
Eur. J. Inorg. Chem. 1999, 117Ϫ127

Zinc Complexes of Aldehydes and Ketones, 2
FULL PAPER
[Zn(A)2(EtOH)2(H2O)2] (ClO4)2
[Zn(BA)5(H2O)](BF4)2
5: A ϭ MA; 6: A ϭ CA
8
Figure 3. Zinc coordination in [Zn(A)2(EtOH)2(H2O)2](ClO4)2 (5:
˚
A ϭ MA, 6: A ϭ CA). Bond lengths [A] and angles [°] for 5/6:
ZnϪO1 2.083(5)/2.098(3), ZnϪO2 2.080(5)/2.057(4), ZnϪO3
2.079(5)/2.011(4), O1ϪC1 1.230(8)/1.225(5), O2ϪC2 1.440(9)/
1.496(9), ZnϪO1ϪC1 130.1(5)/135.1(3), ZnϪO2ϪC2 128.0(4)/
127.0(4), O1ϪCϪC 125.4(7)/122.1(4).
Figure 5. Zinc coordination in [Zn(BA)5(H2O)](BF4)2 (8). Bond
˚
lengths [A] and angles [°] in the two independent molecules:
ZnϪO1 2.091(3)/2.118(3), ZnϪO2 2.080(3)/2.079(3), ZnϪO3
2.105(3)/2.078(3), ZnϪO4 2.096(3)/2.086(3), ZnϪO5 2.070(4)/
2.080(3), ZnϪO6 2.017(4)/2.031(4), O1ϪC1 1.215(6)/1.217(6),
O2ϪC2 1.215(6)/1.213(6), O3ϪC3 1.211(6) /1.224(6), O4ϪC4
1.212(6)/1.213(5), O5ϪC5 1.216(6)/1.231(6), ZnϪO1ϪC1 127.0(3)/
129.6(3), ZnϪO2ϪC2 127.4(3)/126.4(3), ZnϪO3ϪC3 132.3(3)/
130.3(3), ZnϪO4ϪC4 126.6(3)/128.7(3), ZnϪO5ϪC5 135.1(4)/
127.9(3), O1ϪCϪC 123.5(4)/124.3(4), O2ϪCϪC 123.0(5)/123.6(4),
Further removal of water allowed the isolation of mono-
aqua complexes. In the case of 2-chlorobenzaldehyde, four
aldehyde molecules and one perchlorate ion were the other
ligands in complex 7. 7 has the water and perchlorate li-
gands trans to each other (Figure 4). Although the
ZnϪO(aldehyde) bonds are of average length, there is a
trans effect for the two other ZnϪO bonds: the weak (long)
ZnϪperchlorate interaction has a strong (short) ZnϪwater
interaction trans to it.
O3ϪCϪC
122.6(5)/122.5(5),
O4ϪCϪC
124.5(4)/124.5(4),
O5ϪCϪC 122.1(5)/123.5(4).
While no hydrated aldehyde complex of zinc nitrate could
be obtained in a pure state, this was the case for the water-
free complexes. In the reaction with mesitylaldehyde, com-
plex 9 was isolated. The composition of 9 indicated that
three coordination positions would be used for the
zincϪnitrate interactions, i.e. one nitrate ligand would be
monodentate and the other bidentate, a situation observed
many times in octahedral zinc complexes. This was borne
out by the structure determination (Figure 6). The three
[Zn(CA)4(H2O)(ClO4)]ClO4
7
[Zn(MA)3(NO3)2]
9
Figure 4. Zinc coordination in [Zn(CA)4(H2O)(ClO4)]ClO4 (7).
˚
Bond lengths [A] and angles [°]: ZnϪO1 2.078(4), ZnϪO2 2.093(5),
ZnϪO3 2.068(4), ZnϪO4 2.095(4), ZnϪO5 2.032(6), ZnϪO6
2.188(5), O1ϪC1 1.203(7), O2ϪC2 1.218(7), O3ϪC3 1.201(7),
O4ϪC4 1.214(7), ZnϪO1ϪC1 127.8(4), ZnϪO2ϪC2 127.8(4),
ZnϪO3ϪC3 127.2(4), ZnϪO4ϪC4 130.0(4), O1ϪCϪC 123.8(6),
O2ϪCϪC 123.2(6),O3ϪCϪC 123.4(6), O4ϪCϪC 123.1(6),
ZnϪO6ϪCl 132.4(3).
Figure 6. Zinc coordination in [Zn(MA)3(NO3)2] (9). Bond lengths
[A] and angles [°]: ZnϪO1 2.075(2), ZnϪO2 2.032(2), ZnϪO3
˚
Five benzaldehyde ligands are present in complex 8. This
time there is no trans effect associated with the water ligand,
but the average ZnϪO(aldehyde) bond length of 2.09 A is
2.120(2), ZnϪO4 2.017(2), ZnϪO5 2.098(2), ZnϪO6 2.400(2),
O1ϪC1 1.231(3), O2ϪC2 1.218(2), O3ϪC3 1.228(3), O1ϪCϪC
125.2(2), O2ϪCϪC 124.7(2), O3ϪCϪC 126.7(2), ZnϪO1ϪC1
127.7(2), ZnϪO2ϪC2 130.7(1), ZnϪO3ϪC3 119.2(1), O2ϪZnϪO4
125.1(1), O2ϪZnϪO5 96.3(7), O2ϪZnϪO6 150.9(1).
˚
significantly longer than the average ZnϪO(water) bond
length of 2.02 A (Figure 5).
˚
Eur. J. Inorg. Chem. 1999, 117Ϫ127
119

B. Müller, H. Vahrenkamp
FULL PAPER
aldehyde and the three nitrate oxygen atoms are all ar- ligands. The ZnϪO(aldehyde) and ZnϪO(alcohol) bond
ranged meridionally. The unsymmetrically bidentate nature lengths are not significantly different in 13, and all of its
of one nitrate ligand causes a severe distortion of the octa- ZnϪO bond lengths are quite similar to those in 10Ϫ12.
hedral ligand arangement (cf. angles involving O2), and the
lack of a direct trans-ligand makes ZnϪO2 an unusually
short ZnϪO(aldehyde) bond.
[Zn(MA)2(EtOH)2(ClO4)2]
13
Attempts to prepare hexa-aldehyde complexes by way of
quantitative dehydration of the zinc salts did not lead to
the desired products. Instead tetraaldehyde-bisperchlorate
complexes were obtained from Zn(ClO4)2 • 6 H2O. These
compounds were isolated in a crystalline form by reaction
with benzaldehyde, 4-fluorobenzaldehyde and mesitylalde-
hyde as 10, 11, and 12. 12 represents another example that
contained two equivalents of co-crystallized aldehyde. All
three complexes have the four aldehyde ligands in a planar
arrangement and the two perchlorate ligands in a trans-ax-
ial orientation (Figure 7). The presence of two additional
aldehyde molecules per formula unit in the crystals of 12
has no influence on bond lengths or angles around zinc. By
comparison the ZnϪO(aldehyde) bonds are relatively short
and the ZnϪO(perchlorate) bonds typically long.
[Zn(A)4(ClO4)2]
10: A ϭ BA; 11: A ϭ FA; 12: A ϭ MA
˚
Figure 8. Zinc coordination in 13. Bond lengths [A] and angles
[°]: ZnϪO1 2.069(2), ZnϪO2 2.045(3), ZnϪO3 2.151(3), O1ϪC1
1.225(4), O2ϪC2 1.447(4), ZnϪO1ϪC1 125.6(2), ZnϪO2ϪC2
130.5(2), ZnϪO3ϪCl 143.1(2), O1ϪCϪC 126.4(3).
It was thus obvious that the aldehydes are not strong
enough as donors to occupy all six coordination positions
at the zinc ion in the presence of the weakly coordinating
anions NO3Ϫ, BF 4Ϫ, or ClO4Ϫ. We therefore resorted to
solvated zinc hexachloroantimonate as a starting material.
By dissolving [Zn(CH3CN)6](SbCl6)2[20] in the aldehydes we
found that not more than two of the acetonitrile ligands
could be replaced. Complexes 14Ϫ16 were isolated.
trans-[Zn(A)2(MeCN)4] (SbCl6)2
14: A ϭ BA; 15: A ϭ MA
cis-[Zn(CA)2(MeCN)4] (SbCl6)2
16
Figure 7. Zinc coordination in 10, 11, and 12 (10 and 11 have zinc
˚
The structure determinations revealed that 14 and 15 are
trans-configured (Figure 9). The mediocre quality of the
data set for 14 prohibits a detailed comparison, but it is
on an inversion center). Bond lengths [A] and angles [°] for 10/11/
12: ZnϪO1 2.063(1)/2.068(1)/2.072(3), ZnϪO2 2.057(1)/2.044(1)/
2.052(2), ZnϪO3 Ϫ/Ϫ/2.084(3), ZnϪO4 Ϫ/Ϫ/2.043(2), ZnϪO5
2.143(1)/2.159(1)/2.134(3), ZnϪO6 Ϫ/Ϫ/2.230(3), O1ϪC1 1.229(2)/
1.227(2)/1.235(4), O2ϪC2 1.234(2)/1.231(2)/1.233(4), O3ϪC3 Ϫ/Ϫ/ obvious that the ZnϪO and ZnϪN bond lengths in both
1.229(4), O4ϪC4 Ϫ/Ϫ/1.233(4), ZnϪO1ϪC1 129.0(1)/128.3(1)/
complexes are practically identical and that the equatorially
arranged acetonitrile ligands show a variable deviation from
linearity (157Ϫ177°) at their nitrile carbon atoms.
In contrast, complex 16 is cis-configured (Figure 10).
This time there is a distinction between the ZnϪO and
ZnϪN bond lengths, the latter being shorter, and the aceto-
121.2(2), ZnϪO2ϪC2 127.0(1)/128.9(1)/123.8(2), ZnϪO3ϪC3 Ϫ/
Ϫ/125.1(2), ZnϪO4ϪC4 Ϫ/Ϫ/125.2(2), O1ϪCϪC 123.3(2)/
123.1(2)/126.9(3), O2ϪCϪC 122.9(2)/122.2(2)/125.4(3), O3ϪCϪC
Ϫ/Ϫ/125.9(3), O4ϪCϪC Ϫ/Ϫ/125.3(2), ZnϪO5ϪCl 132.8(3)/
133.6(1)/135.0(2), ZnϪO6ϪCl Ϫ/Ϫ 142.4(2).
In complexes like 10Ϫ12 the perchlorate ligands seem to nitrile ligands are closer to being linear. The structural fea-
be more difficult to replace than the aldehyde ligands. This tures do not offer an indication as to why 14 and 15 should
became evident when two equivalents of ethanol were ad- be trans- and 16 cis-configured.
ded to solutions of the fully dehydrated zinc salts in the
neat aldehydes. Complex 13 could be crystallized from its could be achieved by starting with [Zn(CH3NO2)6]-
solution in mesitylaldehyde. Figure 8 shows the all-trans ar- (SbCl6)2[21], as previously reported by Driessen et al.[10][11]
rangement of its pairs of aldehyde, alcohol, and perchlorate The problem of fast decomposition of the products could
A complete replacement of solvate by aldehyde ligands
.
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Eur. J. Inorg. Chem. 1999, 117Ϫ127

Zinc Complexes of Aldehydes and Ketones, 2
FULL PAPER
tural standards for homoleptic zinc-aldehyde complexes
˚
˚
with bond lengths of ca. 2.08 A for ZnϪO and ca. 1.23 A
for CϪO.
˚
Figure 9. Zinc coordination in 14 and 15. Bond lengths [A] and
angles [°] in 14/15: ZnϪO1 2.116(9)/2.103(3), ZnϪN1 2.113(11)/
2.137(4), ZnϪN2 2.117(12)/2.106(5), O1ϪC1 1.20(1)/1.23(1),
ZnϪO1ϪC1
136(1)/129.2(3),
O1ϪCϪC
123(1)/126.4(4),
ZnϪN1ϪC 174(1)/157.3(4), ZnϪN2ϪC 172(1)/165.1(4).
Figure 11. Zinc coordination in 17 and 18 (18 has zinc on an inver-
˚
sion center). Bond lengths [A] and angles [°] for 17/18: ZnϪO1
2.07(1)/2.073(2), ZnϪO2 2.05(1)/2.078(2), ZnϪO3 2.15(1)/2.075(2),
ZnϪO4 2.11(1)/Ϫ, ZnϪO5 2.09(1)/Ϫ, ZnϪO6 2.08(1)/Ϫ, O1ϪC1
1.26(2)/1.219(4), O2ϪC2 1.24(2)/1.219(4), O3ϪC3 1.21(2)/1.222(4),
O4ϪC4 1.25(2)/Ϫ, O5ϪC5 1.19(2)/Ϫ, O6ϪC6 1.28(2)/Ϫ,
ZnϪO1ϪC1 122(1)/124.6(2),
ZnϪO2ϪC2 130(1)/124.5(2),
ZnϪO3ϪC3 119(1)/127.3(2), ZnϪO4ϪC4 125(1)/Ϫ, ZnϪO5ϪC5
130(1)/Ϫ, ZnϪO6ϪC6 130 (1)/Ϫ.
Discussion of the Structures
All these aldehyde complexes are octahedral to a very
good approximation. In most cases the valence angles at
zinc deviate by not more than ±3° from 90° or ±5° from
180°, with the extremes being ±6° and ±8°, respectively. The
aldehyde ligands are attached to zinc in a strict anti fashion,
as expressed by the dihedral angles ZnϪOϪCϪR, which
range from 158° to 180° with an average over all structures
of 174°. Furthermore, and despite some steric hindrance,
the aromatic rings of the aldehydes are always coplanar
with the RCHO functions, again expressed by dihedral
angles ranging from 166° to 179° with an average of 176°.
Details of the ZnϪO bond lengths and some internal
comparisons were mentioned above for the complex types.
Table 1 gives the data for a general comparison. The most
interesting question is whether the bonding strength of the
aldehydes can be deduced from their ZnϪO distances. An
inspection of Table 1 reveals that for a given complex type
there is no distinction between ZnϪO bond lengths accord-
ing to the type of aldehyde. Instead the coligands seem to
have the major influence on the strength of the zinc-alde-
˚
Figure 10. Zinc coordination in 16. Bond lengths [A] and angles
[°]: ZnϪO1 2.168(2), ZnϪO2 2.149(2), ZnϪN1 2.087(3), ZnϪN2
2.165(3), ZnϪN3 2.087(3), ZnϪN4 2.082(3), O1ϪC1 1.215(4),
O2ϪC2 1.216(4), ZnϪO1ϪC1 131.0(2), ZnϪO2ϪC2 128.0(2),
O1ϪCϪC 123.1(4), O2ϪCϪC 123.8(3), ZnϪN1ϪC 177.4(3),
ZnϪN2ϪC 164.3(3), ZnϪN3ϪC 168.4(3), ZnϪN4ϪC 171.5(3).
be overcome for fluoro- and chlorobenzaldehyde, making
compounds 17 and 18 accessible in a pure and crystalline
form.
[Zn(FA)6](SbCl6)2 [Zn(CA)6](SbCl6)2 • 4 CA
17
18
Structurally 17 and 18 are symmetrical octahedral com- hyde interaction. When two or more water (1Ϫ6) or aceto-
plexes (Figure 11). Specifically, 18 shows very uniform bond nitrile ligands (14Ϫ16) are present the ZnϪO(aldehyde)
lengths and angles for the aldehyde ligands and a very nar- bonds are long. In turn, when only aldehyde ligands are
row spread of 88Ϫ92° for the angles at zinc. The lower data present (17, 18) or when only perchlorate is the coligand
quality for 17 seems to have caused a wider spread of bond (10Ϫ12), the ZnϪO(aldehyde) bonds are short. This is an-
lengths and angles, the averages of which, however, agree other demonstration of the fact that the aldehydes are very
well with those for 18. The two complexes define the struc- weak ligands.
Eur. J. Inorg. Chem. 1999, 117Ϫ127
121

B. Müller, H. Vahrenkamp
FULL PAPER
˚
Table 1. Bonding features (average values of bond lengths [A] and
pounds. Instead the very narrow spread of all these ZnϪO
bond lengths (2.08Ϫ2.11 A) indicates that the packing of
angles [°]) for the zincϪaldehyde interactions
˚
six oxygen atoms around one zinc ion does not allow
shorter contacts irrespective of the variation of the attrac-
tive forces.
aldehyde
coligands
ZnϪO
2.13
2.13
2.10
2.12
2.08
OϪC
1.23
1.23
1.23
1.23
1.23
ZnϪOϪC
135
X
ZnϪX
2.06
2.06
2.06
2.04
2.08
2.08
2.01
2.06
2.03
2.19
2.02
2.02
2.10, 2.40
2.14
2.16
2.18
2.05
2.15
2.12
2.12
2.11
Ϫ
1
2
3
4
5
O(H2O)
O(H2O)
O(H2O)
O(H2O)
O(H2O)
O(EtOH)
O(H2O)
O(EtOH)
O(H2O)
O(ClO4)
O(H2O)
O(NO3)
O(NO3)
O(ClO4)
O(ClO4)
O(ClO4)
O(EtOH)
O(ClO4)
N(MeCN)
N(MeCN)
N(MeCN)
Ϫ
136
Spectroscopy
132
126
130
The most important indication for the formation of the
aldehyde complexes was the observation of the aldehyde
ν(CO) IR bands at their typical locations. As shown in
Table 2, the bands for coordinated aldehydes are shifted by
ca. 50Ϫ80 cmϪ1 to lower wavenumbers, which is in agree-
ment with previous observations on zinc-hexaaldehyde
complexes[10][11]. In contrast, those complexes that contain
cocrystallized uncoordinated aldehyde display additional
ν(CO) bands that are practically unshifted.
Contrary to expectation, the ν(CO) band shifts are
neither proportional to the donor strength (i.e. electron
richness of the aromatic system) of the aldehydes nor in-
versely proportional to the donor power of the coligands
(i.e. water stronger than perchlorate). Indeed complex 10,
containing benzaldehyde as one of the better aldehyde do-
nors together with only the very weak donor perchlorate,
shows the smallest ∆ν, and complex 6, containing electron-
poor 2-chlorobenzaldehyde together with two water and
two ethanol ligands, shows the largest ∆ν. There seem to
be, however, rather uniform ∆ν values for each aldehyde,
e.g. Ϫ50 cmϪ1 for BA, Ϫ55 cmϪ1 for MA, Ϫ65 cmϪ1 for
FA, and Ϫ80 cmϪ1 for CA. This trend should be of diag-
nostic value.
6
7
2.10
2.08
1.23
1.21
135
128
8
9
2.09
2.08
1.22
1.23
129
126
10
11
12
13
2.06
2.06
2.06
2.07
1.23
1.23
1.23
1.23
128
129
124
126
14
15
16
17
18
2.12
2.10
2.16
2.09
2.08
1.20
1.23
1.22
1.24
1.22
136
129
130
126
126
Ϫ
Ϫ
The spread of the ZnϪO distances finds no reflection in
the other structural features of the aldehydes. The details of
the aldehyde orientation (cf. dihedral angles, see above)
show no systematic relation with the ZnϪO(aldehyde) bond
lengths. The range of the aldehyde CϭO bond lengths is
too small to warrant a discussion. There is just a barely
noticeable proportionality between the ZnϪOϪC angles
and the ZnϪO(aldehyde) bond lengths. When compared to
the three other reported structures of zinc-aldehyde com-
plexes[13][17][18] the structural features listed in Table 1 span
the range observed there.
The IR data of the coligands and anions also yield some
information (Table 2). While the water and ethanol ligands
Table 2. IR data (KBr, cmϪ1) of the complexes
The coligands in complexes 1Ϫ16 bind to zinc in a fa-
shion that is known to occur in such complexes[22]. Specifi-
cally the bonding alternatives for the nitrate ligand between
strictly monodentate and symmetrically bidentate and the
weak and variable zincϪperchlorate interactions are well
known. Similarly the ZnϪN(acetonitrile) bond lengths in
14Ϫ16 are in the reported range, as are the deviations of
the ZnϪNϪC units from linearity found here (157Ϫ177°)
aldehyde
Ϫ∆ν coligand
anion
¯
1
1685 s, 1635 s 5, 55 3517 m, br
1149 s, 1110 s,
1088 s, 940 m
1148 s, 1034 s
1148 s, 1110 s,
1089 s, 940 m
1043 s, br
1149 s, 1108 s,
1085 s, 940 w
1146 s, 1107 s,
1087 s, 940 w
1109 s, 1088 s
1034 s, br
2
3
1684 s, 1634 s 6, 56 3565 m, br
1685 s, 1636 s 5, 54 3456 m
4
5
1638 s
1635 s
52
55
3448 m
3442 m, br
6
1616 s
50
3526 m
in comparison to the reported range (156Ϫ178°)[22]
.
Complexes 17 and 18 are of general significance as they
7
8
9
1619 s
1651 s
1640 s
79
50
50
3446 m, br
3450 m, br
Ϫ
define the standard of ZnO6 coordination by aldehydes.
1465 s, br, 1390 s,
1290 s, br
1149 s, 1108 s,
1086 s
˚
Their ZnϪO distances of 2.08Ϫ2.09 A compare very well
2ϩ
with the average values for ZnϪO in Zn(H2O)6 (2.09 10 1654 s
47
62
Ϫ
[23]
2ϩ
˚
˚
A)
and in Zn(alcohol)6 (2.08 A)[24]. Other reported
11 1638 s
12 1689 s, 1635 s 1, 55
Ϫ
Ϫ
1150 s, 1095 s, br
1149 s, 1104,
1088 s
complexes with a homoleptic ZnO6 coordination belong to
the types Zn(pyridine oxide)62ϩ[25], Zn(urea)62ϩ[26], and
13 1634 s
14 1650 s
15 1639 s
16 1643 s
17 1635 s
56
51
51
55
65
3415 m
1150 s, 1091 s
2ϩ[27]
Zn(DMSO)6
with average ZnϪO bond lengths of
2316 m, 2290 m Ϫ
2317 m, 2287 m Ϫ
2316 m, 2296 m Ϫ
˚
2.10, 2.10, and 2.11 A, respectively. The ZnϪO bond length
for the aldehyde complexes is at the lower end of all these
ZnO6 species, indicating again that donor strength and
bond distances are not clearly correlated for such com-
Ϫ
Ϫ
Ϫ
Ϫ
18 1698 s, 1627 s 0, 71
122
Eur. J. Inorg. Chem. 1999, 117Ϫ127

Zinc Complexes of Aldehydes and Ketones, 2
FULL PAPER
display a broad and unspecific absorption between 3400
and 3550 cmϪ1, the ν(CN) bands of the acetonitrile ligands
are characteristically shifted by 25Ϫ40 cmϪ1 to higher
wavenumers[28] as compared to those of free CH3CN. The
ν(NO) bands of the nitrate ligands, as is usual[29], give no
clear indication of their bonding mode (uni- or bidentate).
Conclusions
This work has shown that two to six aldehyde molecules
can be coordinated to zinc under carefully controlled con-
ditions. The complexes described here are those that were
isolated in an analytically pure form. Many more have been
prepared in a less pure form, and it is to be assumed that
the various structural types can be realized by most of the
aldehydes. The aldehydes are completely expelled from the
ligand sphere of zinc when excess water is present. In the
presence of strongly coordinating anions like the halides,
Ϫ
Ϫ
The BF 4 and ClO4 ions show their strong absorptions
near 1100 cmϪ1. For perchlorate, a medium-intensity band
near 940 cmϪ1, assignable to a fully symmetrical stretch[19]
,
is observed only in complexes 1, 3, 5, and 6, in accord with
the structural data showing that these complexes contain
completely different structural types are observed[8]
.
Ϫ
uncoordinated ClO4
.
All isolated complexes were found to be octahedral. Nor-
mally they contain one to four coligands together with the
aldehyde ligands. In addition to water, ethanol and aceto-
nitrile can also not be completely replaced by the aldehydes.
Under anhydrous conditions the nitrate and perchlorate
anions are preferred over the aldehydes as ligands. Hexa-
aldehyde complexes could only be obtained by replacement
of the very weak donor nitromethane and by applying an
anion (SbCl6Ϫ) of extremely low donor strength.
The suitability of NMR spectroscopy for bonding dis-
cussions of the aldehyde complexes is hampered by the fact
that, other than in the neat aldehydes, they dissolve only in
polar organic solvents that may be stronger donors for zinc
than the aldehydes. Accordingly, only small shift effects
were observed when recording the spectra in [D6]acetone.
Table 3 lists the data.
1
Table 3. H- and 13C-NMR data for the aldehyde CHO functions
X-ray structure determination was found to be the only
method of unambiguous product identification. It has pro-
vided the structural features of zincϪaldehyde bonding. It
has delivered examples of the basic ZnL6 structure for L ϭ
aldehyde, which need to be complemented for other L, e.g.
alcohol, acetone, ethers, nitromethane, acetonitrile, etc. It
has been shown that slight variations in the reaction con-
ditions can lead to quite different compositions of the com-
plexes. Together with the low donor strength of the alde-
hydes this means that there exists a high degree of uncer-
tainty when mechanistic conclusions are drawn from such
structures or even from the composition of reaction solu-
tions.
(in [D6]acetone, δ)
δ(H)
∆δ
δ(C)
∆δ
1
10.49
10.46
10.50
10.49
10.48
10.31
10.39
10.12
10.45
9.96
ϩ0.01
Ϫ0.02
ϩ0.02
ϩ0.01
±0
Ϫ0.05
ϩ0.03
ϩ0.06
Ϫ0.03
Ϫ0.10
ϩ0.05
Ϫ0.02
±0
193.9
194.1
193.8
193.8
194.4
190.2
190.0
193.4
195.3
194.6
191.7
194.8
194.6
193.0
193.5
189.8
191.3
189.7
ϩ1.3
ϩ1.5
ϩ1.2
ϩ1.2
ϩ1.8
ϩ0.8
ϩ0.6
ϩ0.7
ϩ2.7
ϩ1.9
ϩ0.9
ϩ2.2
ϩ2.0
ϩ0.3
ϩ0.9
ϩ0.4
ϩ0.5
ϩ0.3
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
10.00
10.46
10.48
10.01
10.50
10.39
9.96
With respect to modelling the zinc enzyme alcohol de-
hydrogenase, this work has provided some elementary infor-
mation. On the one hand it was shown that aldehydes can
be bound to zinc in the presence of water, i.e. zinc can be
involved in the process of aldehyde reduction. On the other
hand it has become very clear that excess water replaces
zinc-bound aldehydes very easily, e.g. the last step of al-
cohol oxidation is facile. Furthermore, the possible coexist-
ence of alcohol and aldehyde ligands in the same complex
was demonstrated. With respect to the chemical reactions
happening in the enzyme, the findings of this work are of
little relevance as neither the low coordination number of
zinc nor the presence of a redox reagent were reproduced.
It was partly for this reason that we extended our studies
of zincϪaldehyde coordination to further types of ligands
Ϫ0.05
ϩ0.02
ϩ0.03
ϩ0.01
ϩ0.03
10.39
Metal coordination of the aldehyde function should lead
to deshielding of both the H and C of RCHO. Such a de-
shielding is actually observed with ∆δ values of 1Ϫ2 ppm
for the 13C resonances while the 1H resonances are so close
to those of the free aldehydes that they cannot be discussed.
The extent of deshielding decreases in the order MA > BA
> FA > CA, which can be correlated with the donor
strengths. The NMR spectra, however, do not show a dis-
tinction between coordinated and uncoordinated aldehydes
in complexes 1Ϫ3, 12, and 18.
and coligands[8][9]
.
The coligands ethanol and acetonitrile seem to stay coor-
1
dinated to zinc in acetone solutions. Their H-NMR reso-
Experimental Section
nances are shifted by 0.5Ϫ1 ppm to lower field in compari-
son to those of the free ligands. Likewise the 13C-NMR
signals are shifted downfield by up to 2.5 ppm for ethanol-
CH2, but show almost no shift for the acetonitrile reso-
nances.
The general working and measuring techniques were as described
previously[30]. All experiments were carried out using carefully
dried atmospheres (nitrogen or argon) and solvents. As some of the
products were too moisture-sensitive for ordinary C/H/N analyses,
all compounds were also characterized by zinc and anion analyses
Eur. J. Inorg. Chem. 1999, 117Ϫ127
123

B. Müller, H. Vahrenkamp
FULL PAPER
Table 4. Reaction details
Compl.
zinc salt
HC(OEt)3
aldehyde/EtOH
yield
m.p.
°C
g
mmol mL
g
mmol
mL
g
mmol
g
%
1
2
3
4
5
Zn(H2O)6(ClO4)2
1.58
1.09
0.92
0.56
1.03
4.25
3.14
2.47
1.61
2.77
2.12
1.57
2.05
1.35
2.30
1.89
1.40
1.83
1.20
2.05
12.75 MA
9.42 MA
12.35 MA
8.07 MA
13.83 MA
10
7
10.05 67.81 3.71
94
93
71
42
50
91
99
87
93
70
Zn(H2O)6(BF4)2
Zn(H2O)6(ClO4)2
Zn(H2O)6(BF4)2
Zn(H2O)6(ClO4)2
7.04
5.03
5.03
5.03
47.50 2.64
33.94 2.08
33.94 0.59
33.94 0.95
5.43
5
5
5
EtOH 0.323 0.25
6
Zn(H2O)6(ClO4)2
1.03
2.77
2.29
2.04
13.79 CA
5
6.24
44.39 1.25
5.43
67
80
EtOH 0.323 0.25
7
Zn(H2O)6(ClO4)2
Zn(H2O)6(BF4)2
Zn(H2O)6(NO3)2
Zn(H2O)6(ClO4)2
Zn(H2O)6(ClO4)2
Zn(H2O)6(ClO4)2
Zn(H2O)6(ClO4)2
1.01
0.81
0.48
1.19
1.10
0.87
1.04
2.71
2.33
1.61
3.20
2.95
2.34
2.79
2.71
2.34
2.14
4.25
3.93
3.11
3.72
2.41
2.08
1.91
3.79
3.50
2.77
3.31
16.27 CA
14.00 BA
12.91 MA
25.57 BA
23.63 FA
18.69 MA
22.34 MA
5
5
6.24
5.22
44.39 0.52
49.19 1.06
23
58
70
73
23
70
28
131
8
87
9
10
9
10.05 67.81 0.72
79
10
11
12
13
9.40
5.79
5.03
5.03
88.54 1.60
46.65 0.52
33.94 1.88
33.94 0.51
5.64
122
5
135 (dec.)
81
5
5
117
EtOH 0.325 0.26
14
15
16
17
18
Zn(MeCN)6(SbCl6)2 1.09
Zn(MeCN)6(SbCl6)2 1.45
Zn(MeCN)6(SbCl6)2 1.23
Zn(MeNO2)6(SbCl6)2 1.65
Zn(MeNO2)6(SbCl6)2 1.51
1.11
1.48
1.25
1.50
1.37
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
BA
MA
CA
FA
5
5
5
5
5
5.22
5.03
6.24
5.79
6.24
49.19 1.07
33.94 1.28
44.39 1.27
46.65 2.10
44.39 2.66
87
72
86
95
91
117 (dec.)
93 (dec.)
86
105
CA
80
Table 5. Analytical characterization
(Table 5). All starting compounds were obtained commercially,
recrystallized or distilled prior to use, and stored under anhydrous
conditions. The acetonitrile[20] and nitromethane[21] complexes of
zinc were prepared as described. Although none of the perchlorate-
containing materials were found to be explosive, all of them were
handled in small quantities and with the appropriate safety pre-
cautions. The new complexes were prepared following two pro-
cedures that are outlined below and the details for which are given
in Table 4. Table 5 gives data of the analytical characterizations.
formula
mol. wt.
Analyses calcd./found
Zn X
C
H
1
2
3
C20H32Cl2O14Zn •
51.71/ 6.08/ 7.04/ ClO4 21.41/
52.05 6.07 7.01 21.50
2 C10H12
O
632.8 ϩ 296.4
C20H32B2F8O6Zn •
Ϫ
Ϫ
7.23/ BF4 25.45/
7.17 25.34
2 C10H12
O
607.5 ϩ 296.4
Ϫ
Ϫ
Ϫ
Ϫ
C40H52Cl2O14Zn •
2 C10H12
5.50/ ClO4 16.72/
5.56 16.84
Preparation of Complexes 1Ϫ13: The hydrated zinc salt was dis-
solved in the appropriate amount of triethoxymethane (n ϩ 1
equivalents for removal of n equivalents of water). The solution
was heated to reflux using a hot air blower for a few seconds. After
cooling to room temperature, all volatiles were removed in vacuo
and the residue dried in vacuo at 40Ϫ50°C for 2 h. An approxi-
mately 10-fold excess of the aldehyde was then added and the mix-
ture stirred with warming until all reactants had dissolved. After
cooling the solution to room temperature the aldehyde solution was
layered carefully with 30 mL of petroleum ether (b.p. 60Ϫ70°C).
Within one to two days the colourless product complex had precipi-
tated. In those cases where the product was crystalline it was also
found to be pure. The complex was filtered off, washed with a small
amount of petroleum ether (b.p. 60Ϫ70°C) and dried in vacuo.
O
893.2 ϩ 296.4
C40H52B2F8O6Zn
867.9
Ϫ
Ϫ
4
5
6
7
8
9
55.36/ 6.04/ 7.54/ BF4 20.01/
56.86 6.11 7.62 19.96
41.85/ 5.85/ 9.49/ ClO4 28.87/
41.64 5.82 9.62 28.95
32.10/ 3.89/ 9.71/ ClO4 29.53/
32.56 3.38 9.84 29.76
39.82/ 2.63/ 7.74/ ClO4 23.55/
39.46 2.76 7.80 23.41
53.37/ 4.10/ 8.30/ BF4 22.04/
54.78 3.33 8.36 21.83
10.31/ NO3 19.56/
10.24 19.62
9.49/ ClO4 28.88/
9.61 28.64
C24H40Cl2O14Zn
688.9
C18H26Cl4O14Zn
673.6
C28H22Cl6O13Zn
844.6
C35H32B2F8O6Zn
787.6
C30H36N2O9Zn
634.0
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
10 C28H24Cl2O12Zn
688.8
11 C28H20Cl2F4O12Zn
760.8
44.21/ 2.65/ 8.60/ ClO4 26.15/
44.10 2.57
Ϫ
8.58
5.67/ ClO4 17.24/
5.69 17.21
26.23
Preparation of Complexes 14Ϫ18: The solvated zinc salt was sus-
pended in 5 mL of dichloromethane. 5 mL of the aldehyde was
added with stirring upon which a clear solution was formed. This
solution was layered carefully with 40 mL of petroleum ether (b.p.
60Ϫ70°C). Within a few days the product complex had precipitated
as colourless crystals, which were filterd off, washed with a few
mL of petroleum ether (b.p. 60Ϫ70°C) and dried for a short time
in vacuo.
12 C40H48Cl2O12Zn •
Ϫ
2 C10H12
O
857.1 ϩ 296.4
13 C24H36Cl2O12Zn
652.8
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
10.02/ ClO4 30.47/
9.98
30.38
38.30/
38.42
35.60/
35.68
42.07/
42.18
28.77/
28.86
36.45/
36.73
14 C22H24Cl12N4O2Sb2Zn
1110.8
5.89/ Cl
5.74
15 C28H36Cl12N4O2Sb2Zn
1194.9
16 C22H22Cl14N4O2Sb2Zn 22.40/ 1.88/ 5.54/ Cl
5.47/ Cl
5.52
Structure Determinations[31]: Crystals were obtained from the reac-
tion solutions. The crystals were then immersed in perfluorinated
polyether oil for protection and attachment to the goniometer head
and immediately subjected to the nitrogen flow from the dif-
fractometerЈs cooling system. Diffraction data were recorded at low
temperatures with the ω/2θ technique on a Nonius CAD4 dif-
1179.7
17 C42H30Cl12F6O6Sb2Zn 34.11/ 2.05/ 4.42/ Cl
1479.0 34.31 2.26 4.39
22.37 1.67
5.50
18 C42H30Cl18O6Sb2Zn • 39.29/ 2.36/ 3.06/ Cl
4 C7H5ClO
1577.7 ϩ 562.3
38.72 2.62
3.14
124
Eur. J. Inorg. Chem. 1999, 117Ϫ127

Zinc Complexes of Aldehydes and Ketones, 2
fractometer fitted with a molybdenum tube (Kα, λ ϭ 0.7107 A) CϪH and water and alcohol OϪH hydrogen atoms were located
FULL PAPER
˚
and a graphite monochromator. No absorption corrections were
applied. The structures were solved by direct methods and refined
anisotropically with the SHELX program suite[32]. The aldehyde
and refined freely. All other hydrogen atoms were included with
fixed distances and isotropic temperature factors 1.2 times those of
their attached atoms. Parameters were refined against F2. The R
Table 6, part 1. Crystallographic details
1
2
3
4
5
6
formula
C20H32Cl2O14Zn
C20H32B2F8O6Zn C40H52Cl2O14Zn
C40H52B2F8O6Zn C24H40Cl2O14Zn
C18H26Cl4O14Zn
• 2 C10H12
929.12
O
• 2 C10H12
903.84
O
• 2 C10H12
1189.48
O
mol. mass
crystal size [mm] 0.9 ϫ 0.6 ϫ 0.5
867.81
0.8 ϫ 0.7 ϫ 0.6
688.83
0.6 ϫ 0.5 ϫ 0.4
673.56
0.9 ϫ 0.7 ϫ 0.5
1.2 ϫ 0.8 ϫ 0.7
0.6 ϫ 0.5 ϫ
0.5
¯
¯
¯
¯
¯
space group
P1
P1
P1
P21/c
2
P1
P1
Z
1
1
1
1
1
˚
a [A]
8.560(2)
11.565(2)
11.587(4)
71.94(2)
87.29(2)
84.56(2)
1085.5(5)
1.42
8.500(6)
11.505(3)
11.547(3)
72.48(2)
87.16(4)
85.20(4)
1072.7(9)
1.340
8.008(2)
14.046(7)
14.721(3)
109.89(4)
91.30(2)
98.50(3)
1535.2(9)
1.29
8.172(2)
15.484(2)
17.248(3)
90
7.734(1)
8.828(1)
12.507(2)
79.14(1)
89.46(1)
65.60(1)
761.5(2)
1.502
7.604(1)
7.616(1)
12.640(1)
86.68(1)
75.69(1)
71.54(1)
672.6(2)
1.66
˚
b [A]
c [A]
˚
α [°]
β [°]
γ [°]
101.980(15)
90
3
˚
V [A ]
2134.9(6)
1.35
1.33
183(2)
0.65
d(calc.) [g•cmϪ3
]
]
d(obs.) [g•cmϪ3
1.41
1.39
1.27
Ϫ
1.61
183(2)
1.38
temp. [K]
183(2)
183(2)
0.66
293(2)
0.55
183(2)
1.05
µ(Mo-Kα) [mmϪ1
hkl range
]
0.76
h: Ϫ10 to 10
k: Ϫ14 to 13
l: Ϫ14 to 0
4498
h: Ϫ10 to 0
k: Ϫ14 to 14
l: Ϫ14 to 14
4508
h: Ϫ9 to 9
k: Ϫ17 to 0
l: Ϫ17 to 18
6256
h: Ϫ10 to 9
k: 0 to 19
l: 0 to 21
4318
h: Ϫ9 to 9
k: Ϫ10 to 10
l: Ϫ14 to 0
2662
h: 0 to 9
k: Ϫ8 to 9
l: Ϫ15 to 15
2849
refl. measd.
indep. refl.
4276
4208
6000
4176
2531
2641
obs. refl. [I>2σ(I)] 4116
4068
5047
3777
1752
2502
parameters
284
285
366
267
191
175
refl. refined
R1 (obs. refl.)
wR2 (all refl.)
4276
0.026
0.076
4208
6000
4176
2531
2641
0.062
0.055
0.031
0.058
0.055
0.204
0.183
0.087
0.175
0.132
residual el. density ϩ0.3
ϩ1.3
ϩ0.9
ϩ0.4
ϩ0.6
ϩ1.4
Ϫ3
˚
[e/A
]
Ϫ0.5
Ϫ2.1
Ϫ0.5
Ϫ0.4
Ϫ1.0
Ϫ1.0
Table 6, part 2. Crystallographic details
7
8
9
10
11
12
formula
C28H22Cl6O13Zn
844.53
C35H32B2F8O6Zn C30H36N2O9Zn
C28H24Cl2O12Zn
688.74
C28H20Cl2F4O12Zn C40H48Cl2O12Zn
• 2 C10H12
1153.45
O
mol. mass
787.60
1.1 ϫ 1.0 ϫ 1.0
P21
633.98
760.71
crystal size [mm] 1.2 ϫ 1.0 ϫ 0.5
1.2 ϫ 1.0 ϫ 0.9 0.6 ϫ 0.5 ϫ 0.4
1.2 ϫ 1.2 ϫ 0.3
0.8 ϫ 0.7 ϫ 0.6
P21
2
¯
¯
space group
C2/c
8
34.263(6)
14.709(3)
13.677(3)
90
94.640(16)
90
6870(2)
1.633
1.610
Pbca
8
P1
P1
Z
4
1
1
˚
a [A]
10.250(1)
20.549(3)
17.602(3)
90
15.65(4)
17.40(3)
22.24(4)
90
8.637(3)
9.472(1)
10.350(3)
68.55(2)
68.88(2)
69.99(2)
713.2(3)
1.60
8.366(1)
9.776(1)
10.533(1)
68.62(1)
68.71(1)
70.56(1)
727.2(1)
1.74
13.967(1)
14.059(2)
14.493(1)
90
˚
b [A]
c [A]
˚
α [°]
β [°]
γ [°]
90.220(12)
90
90
90.820(9)
90
90
3
˚
V [A ]
3707.4(9)
1.411
1.384
183(2)
0.75
6058(2)
1.390
1.384
183(2)
0.87
2845.6(5)
1.346
1.322
183(2)
0.59
d(calc.) [g•cmϪ3
]
]
d(obs.) [g•cmϪ3
1.59
183(2)
1.11
Ϫ
temp. [K]
293(2)
] 1.24
183(2)
1.12
µ(Mo-Kα) [mmϪ1
hkl range
h: Ϫ41 to 41
k: 0 to 18
l: 0 to 16
4376
h: Ϫ12 to 12
k: Ϫ25 to 0
l: 0 to 22
7940
h: Ϫ18 to 0
k: 0 to 20
l: 0 to 26
5259
h: Ϫ10 to 9
k: Ϫ11 to 10
l: Ϫ12 to 0
2960
h: Ϫ10 to 9
k: Ϫ12 to 0
l: Ϫ12 to 12
3016
h: Ϫ17 to 17
k: 0 to 17
l: Ϫ18 to 0
6456
refl. measd.
indep. refl.
4376
7692
5258
2798
2840
6210
obs. refl. [I>2σ(I)] 4376
7213
4553
2701
2765
5576
parameters
441
945
379
196
214
694
refl. refined
R1 (obs. refl.)
wR2 (all refl.)
4376
0.057
0.171
7692
5258
2798
2840
6210
0.041
0.032
0.093
ϩ0.5
0.027
0.034
0.037
0.124
0.079
0.094
0.108
residual el. density ϩ1.0
ϩ0.5
ϩ0.4
ϩ0.7
ϩ0.5
Ϫ3
˚
[e/A
]
Ϫ0.6
Ϫ0.4
Ϫ0.6
Ϫ0.5
Ϫ0.9
Ϫ0.5
Eur. J. Inorg. Chem. 1999, 117Ϫ127
125

B. Müller, H. Vahrenkamp
FULL PAPER
Table 6, part 3. Crystallographic details
13
14
15
16
17
18
formula
C24H36Cl2O12Zn C22H24Cl12N4-
O2Sb2Zn
C28H36Cl12N4-
O2Sb2Zn
C22H22Cl14N4-
O2Sb2Zn
C42H30Cl12F6O6
Sb2Zn
C42H30Cl18O6
Sb2Zn
• C7H5FO
1603.04
• 4 C7H5ClO
2139.87
mol. mass
crystal size [mm]
652.80
1110.72
1194.88
1179.61
0.6 ϫ 0.2 ϫ 0.1 0.2 ϫ 0.2 ϫ 0.1 0.4 ϫ 0.4 ϫ 0.3 0.5 ϫ 0.4 ϫ 0.3 0.7 ϫ 0.5 ϫ 0.4
0.7 ϫ 0.5 ϫ
0.5
¯
space group
P21/c
2
Pbca
4
P21/n
2
13.237(5)
12.906(7)
13.637(7)
90
102.26(4)
90
2276.6(2)
1.74
Ϫ
183(2)
2.436
C2/c
8
28.648(3)
11.432(1)
25.909(2)
90
100.64(1)
90
8339.4(1)
1.88
Ϫ
183(2)
2.78
P1
1
P1
Z
1
˚
a [A]
12.077(2)
15.989(2)
7.390(2)
90
19.63(2)
10.12(2)
20.25(2)
90
11.450(1)
11.851(1)
14.604(2)
66.25(1)
67.06(1)
74.78(1)
1657.4(3)
1.61
12.386(1)
13.803(1)
15.211(2)
114.05(1)
93.58(1)
112.57(1)
2117.8(3)
1.68
˚
b [A]
c [A]
˚
α [°]
β [°]
γ [°]
96.31(2)
90
90
90
3
˚
V [A ]
1418.4(5)
1.53
1.50
183(2)
1.12
4023(8)
1.83
d(calc.) [g•cmϪ3
]
]
d(obs.) [g•cmϪ3
Ϫ
Ϫ
183(2)
1.71
Ϫ
183(2)
1.66
temp. [K]
183(2)
2.749
h: 0 to 23
k: Ϫ11 to 0
l: 0 to 23
3419
µ(Mo-Kα) [mmϪ1
hkl range
]
h: Ϫ14 to 14
k: 0 to 19
l: Ϫ9 to 0
3007
h: Ϫ15 to 15
k: 0 to 14
l: 0 to 15
3204
h: Ϫ39 to 13
k: Ϫ14 to 13
l: Ϫ31 to 31
14166
8594
h: Ϫ13 to 13
k: 0 to 14
l: Ϫ16 to 17
6220
h: Ϫ15 to 15
k: Ϫ15 to 17
l: Ϫ18 to 0
8629
refl. measd.
indep. refl.
obs. refl. [I>2σ(I)]
parameters
2782
3416
3204
6216
8295
2027
2298
3204
6723
5716
7371
182
191
223
408
703
503
refl. refined
R1 (obs. refl.)
wR2 (all refl.)
2782
3416
3204
8594
6216
8295
0.039
0.081
0.233
ϩ2.4
Ϫ1.9
0.028
0.028
0.056
0.034
0.104
0.090
0.077
0.192
0.098
residual el. density ϩ0.6
ϩ0.5
ϩ1.3
ϩ3.0
ϩ1.1
Ϫ3
˚
[e/A
]
Ϫ0.4
Ϫ0.6
Ϫ0.9
Ϫ0.8
Ϫ1.0
[10]
2
W. L. Driessen, W. L. Groeneveld, Rec. Trav. Chim. Pays Bas
1971, 90, 87Ϫ96.
values are defined as R1 ϭ Σ Fo Ϫ Fc /ΣFo and wR2 ϭ {Σ[w(Fo
Ϫ
Fc2)2]/Σ[w(Fo2)2]}1/2. Drawings were produced with SCHAKAL[33]
.
[11]
P. L. Verheijdt, P. H. van der Voort, W. L. Groeneveld, W. L.
Driessen, Rec. Trav. Chim. Pays Bas 1972, 91, 1201Ϫ1204.
F. Filippini, B. P. Susz, Helv. Chim. Acta 1971, 54, 835Ϫ845.
M. Bochmann, K. J. Webb, M. B. Hursthouse, M. Mazid, J.
Chem. Soc., Chem. Commun. 1991, 1735Ϫ1737.
R. H. Prince, P. Wyeth, J. Inorg. Nucl. Chem. 1981, 43,
839Ϫ843.
Table 6 lists the crystallographic data.
[12]
[13]
Acknowledgments
[14]
[15]
[16]
This work was supported by the Deutsche Forschungsgemein-
schaft.
R. H. Prince, P. Wyeth, J. Inorg. Nucl. Chem. 1981, 43,
845Ϫ848.
M. Bochmann, G. Bwembya, R. Grinter, A. K. Powell, K. J.
Webb, M. B. Hursthouse, M. Mazid, K. M. Abdul Malik, Inorg.
Chem. 1994, 33, 2290Ϫ2296.
M. P. Byrn, C. J. Curtis, Y. Hsiou, S. I. Khan, P. A. Sawin, S.
K. Tendick, A. Terzis, C. E. Strouse, J. Am. Chem. Soc. 1993,
115, 9480Ϫ9497.
I. Goldberg, H. Kruptsky, Z. Stein, Y. Hsiou, C. E. Strouse,
Supramol. Chem. 1994, 4, 203Ϫ221.
P. W. N. M. van Leeuwen, Rec. Trav. Chim. Pays Bas 1967,
86, 247Ϫ253.
A. P. Zuur, W. L. Groeneveld, Rec. Trav. Chim. Pays Bas 1967,
86, 1089Ϫ1102.
W. L. Driessen, W. L. Groeneveld, Rec. Trav. Chim. Pays Bas
1969, 88, 491Ϫ498.
[1]
B. Müller, M. Ruf, H. Vahrenkamp, Angew. Chem. 1994, 106,
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2164Ϫ2165; Angew. Chem. Int. Ed. Engl. 1994, 33, 2089Ϫ2090.
[2]
Comprehensive Organic Synthesis (Eds.: B. M. Trost, I. Fleming,
S. L. Schreiber), Pergamon Press, Oxford, 1991. C. Elschen-
broich, A. Salzer, Organometallic Chemistry, Teubner,
Stuttgart, 1994.
[18]
[19]
[20]
[21]
[22]
[3]
J. J. R. Frausto da Silva, R. J. P. Williams, The Biological Chem-
istry of the Elements, Clarendon Press, Oxford, 1994. Ϫ W.
Kaim, B. Schwederski, Bioanorganische Chemie, Teubner Studi-
enbücher, Stuttgart, 1995.
[4]
Comprehensive Coordination Chemistry (Eds.: G. Wilkinson, R.
D. Gillard, J. A. McCleverty), Pergamon Press, Oxford, 1988.
Ϫ Y.-H. Huang, J. A. Gladysz, J. Chem. Ed. 1988, 65, 298Ϫ303.
Ϫ S. Shambayati, W. E. Crowe, S. L. Schreiber, Angew. Chem.
1990, 102, 273Ϫ290; Angew. Chem. Int. Ed. Engl. 1990, 29,
256Ϫ273.
The Cambridge Crystallographic Data File contains about 20
references each for ZnϪalcohol, ZnϪnitrate, and ZnϪaceto-
nitrile and 12 references for ZnϪperchlorate complexes.
The Inorganic Crystal Structure Database lists Zn(H2O)6 salts
[23]
[5]
H. Vahrenkamp, Acc. Chem. Res. in the press.
˚
with ZnϪO distances between 2.045 and 2.138 A.
[6]
H. Eklund, B. Nordström, E. Zeppezauer, G. Söderlund, I.
Ohlsson, T. Boiwe, B. O. Söderberg, O. Tapia, C. I. Bränden,
[24]
[25]
C. Sudbrake, B. Müller, H. Vahrenkamp, unpublished.
C. J. OЈConnor, E. Sinn, R. L. Carlin, Inorg. Chem. 1977, 16,
3314Ϫ3320.
W. van de Giesen, C. H. Stam, Cryst. Struct. Commun. 1972,
1, 257Ϫ260.
I. Persson, Acta Chem. Scand. Ser. A, 1982, 36, 7Ϫ12.
J. Reedijk, A. P. Zuur, W. L. Groeneveld, Rec. Trav. Chim. Pays
Bas 1967, 86, 1127Ϫ1137.
˚
˚
A. Akeson, J. Mol. Biol. 1976, 102, 27Ϫ59.
H. Vahrenkamp, Lecture at the XXXIII International Confer-
ence on Coordination Chemistry, Firenze, 1998, Book of Ab-
stracts, p. 131.
[7]
[26]
[27]
[28]
[8]
[9]
B. Müller, H. Vahrenkamp, Eur. J. Inorg. Chem. 1999, 129Ϫ135,
succeeding paper.
B. Müller, H. Vahrenkamp, Eur. J. Inorg. Chem. 1999, 137Ϫ144,
next-succeeding paper.
[29]
R. Gregorzik, J. Wirbser, H. Vahrenkamp, Chem. Ber. 1992,
126
Eur. J. Inorg. Chem. 1999, 117Ϫ127

Zinc Complexes of Aldehydes and Ketones, 2
FULL PAPER
125, 1575Ϫ1581. Ϫ C. Titze, J. Hermann, H. Vahrenkamp,
Chem. Ber. 1995, 128, 1095Ϫ1103.
able free of charge from the following address: The Director,
CCDC, 12 Union Road, GB-Cambridge CB2 1EZ (Telefax: Int.
ϩ44 (0)1223/ 336 033; E-mail: deposit@chemcrys.cam.ac.uk).
For a limited time they are also available on the Internet Web
Site www.chemie.uni-freiburg.de/aoanchem/hv/data.html.
G. M. Sheldrick, SHELX-86 and SHELXL-93, Programs for
Crystal Structure Determination, Universität Göttingen, 1986
and 1993.
[30]
M. Förster, R. Burth, A. K. Powell, T. Eiche, H. Vahrenkamp,
Chem. Ber. 1993, 126, 2643Ϫ2648.
The crystallographic data of the structures described in this
[31]
[32]
[33]
paper were deposited with the Cambridge Crystallographic
Data Centre as supplementary publications no. CCDC-102427
(for 1), 102428 (for 2), 102429 (for 3), 102430 (for 4), 102431
(for 5), 102432 (for 6), 102433 (for 7), 102434 (for 8), 102435
(for 9), 102436 (for 12), 102437 (for 10), 102438 (for 11), 102439
(for 13), 102440 (for 15), 102441 (for 14), 102442 (for 16),
102443 (for 17), 102444 (for 18). Copies of these data are avail-
E. Keller, Program SCHAKAL, Universität Freiburg, 1997.
Received August 3, 1998
[I98256]
Eur. J. Inorg. Chem. 1999, 117Ϫ127
127