Synthesis and Structural Characterisation of Lithium, Zinc, and Aluminium Pyrazolate Complexes

Article abstract of DOI:10.1071/CH19417

The reaction of nBuLi with 3,5-dimethylpyrazole (MepzH) in EtO or tmeda/hexane (tmeda = N,N,N,N-tetramethylethane-1,2-diamine) and with 3,5-dimethyl-4-nitropyrazolate (MepzHNO) in THF results in the formation of three structurally diverse lithium pyrazola

Full text of DOI:10.1071/CH19417

RESEARCH FRONT
CSIRO PUBLISHING
Aust. J. Chem.
Full Paper
https://doi.org/10.1071/CH19417
Synthesis and Structural Characterisation of Lithium,
Zinc, and Aluminium Pyrazolate Complexes*
A
A
,
D
B
C
Nazli E. Rad, Peter C. Junk,
Jun Wang
Glen B. Deacon, Ilya V. Taidakov, and
A
A
College of Science and Engineering, James Cook University, Townsville, Qld 4811,
Australia.
B
School of Chemistry, Monash University, Clayton, Vic. 3800, Australia.
C
P. N. Lebedev Physical Institute, Russian Academy of Sciences, 53 Leninsky Prospect,
Moscow 119991, Russia.
D
Corresponding author. Email: peter.junk@jcu.edu.au
0
0
The reaction of nBuLi with 3,5-dimethylpyrazole (Me pzH) in Et O or tmeda/hexane (tmeda ¼ N,N,N ,N -tetramethyl-
2
2
ethane-1,2-diamine) and with 3,5-dimethyl-4-nitropyrazolate (Me pzHNO ) in THF results in the formation of three
2
2
structurally diverse lithium pyrazolates: namely an Et O-solvated tetrameric complex [Li (Me pz) (OEt ) ], bridged
4
2
4
2
2 4
2
1
entirely with m-Z :Z -pyrazolate bonding, a hexanuclear complex [Li (Me pz) (tmeda) ] with four different coordination
modes (m-Z :Z , m-Z :Z , m -Z :Z :Z and m -Z :Z :Z ), and a new polymeric compound [Li (Me pzNO ) (thf) ] , with
6
2
6
2
1
1
2
1
1
2
1
2
2
1
3
3
2
2
2 2
2 n
[
1
Li (Me pzNO ) (thf) ] groups linked by –NO coordination. A mononuclear zinc complex [Zn(tBu pz) (tBu pzH) ].
/2THF (tBu pzH ¼ 3,5-di-tert-butylpyrazole) was prepared by reaction of tBu pzH with ZnEt , unidentate tBu pz groups
2
2 2 2 2 2 2 2 2 2 2
2
2
2
2
being stabilised by N–H?N hydrogen bonding. Treatment of 3,5-diphenylpyrazole (Ph pzH) with trimethylaluminium
(
mole ratio 3 : 1) in THF led to the formation of dinuclear [AlMe (m-Ph pz)] .1/2THF.
2
2
2
Manuscript received: 28 August 2019.
Manuscript accepted: 18 October 2019.
Published online: 14 January 2020.
Introduction
Synthetic advances have provided a wide variety of structurally
varied pyrazoles, which on deprotonation can give rise to a
varied range of pyrazolate ligands. These have considerable
are metathesis reagents for the synthesis of transition and main
[2b–d,10b]
group metal derivatives.
[1]
The chemistry of organozinc pyrazolate complexes is
dominated by the formation of dimeric pyrazolate-bridged
[
2]
[2b]
[10,11a]
coordination flexibility and can coordinate in over 20 ways;
theycan formthe basisofligands thatstabilise multinuclearcages
compounds with four-coordinate Zn centres.
mation of three structurally diverse alkylzinc pyrazolates by
The for-
[2c,d]
and polymers
and can have several coordination modes in the
one complex. In main group element chemistry, it has been
the reaction of R Zn (R ¼ Et, tBu) with 3,5-diphenylpyrazole
2
[2e]
has been reported. The character of both the Zn-bonded alkyl
substituents and solvents influenced the structural type of alkyl-
zinc species isolated, namely [tBuZn(Ph pz)] , [Et Zn (Ph pz) ],
2
possible to achieve Z -bonding rather than the more expected
1
1
[3a]
[3b,c]
m-Z :Z -ligation for K, Mg, Ca, Sr, and Ba,
and toa Group
[5]
3 centre. In addition, stabilisation of bridging CH NtBu,
2
3
2
3
2
4
[4]
[11b]
1
and [Et Zn (Ph pz) (m-thf)].
2
2
2
2
2
[6a,b]
[6c]
alkyl,
azolate ligands as bridging scaffolds. A polynuclear potassium
and hydride has been achieved by employing pyr-
Besides the highlights relating to aluminium pyrazolates
[4–6]
[6]
[4a]
above,
these have shown unexpected reactivity,
provided the first monomeric homoleptic tris(pyrazolato) com-
and
pyrazolate [K(Ph pz)(thf)] (Ph pz¼ 3,5-diphenylpyrazolate)
2
6
2
was the first structurally characterised Group 1 pyrazolate and
plex of any element with [Al(tBu pz) ] (tBu pzH ¼ 3,5-di-tert-
2
3
2
1
2
1
[7]
[4b]
[12,13]
incorporated the new m -Z :Z :Z -binding mode. It was then
butylpyrazole),
as well as pyrazolate bridged dimers.
3
[8]
observed in thallium(I) pyrazolates in accord with the known
I
similarities between K and Tl coordination behaviour.
Later, the redox transmetallation–ligand exchange reaction
developed for lanthanoid metals was found to be applicable to
[
14]
The structures of Group 1 pyrazolates (examples above) are
[
Al metal and [Al(tBu pz) (thf)] was isolated.
2 3
9,10a,b]
of continuing interest despite many reported examples,
the responses of pyrazolate ligation to the high Lewis acidity of
as
Herein, we report the synthesis and structural characterisa-
tion of [Li (Me pz) (OEt ) ] (Li1) and [Li (Me pz) (tmeda) ]
4
2
4
2 4
6
2
6
2
[3a,9,10a,b]
Group 1 metal ions are many and varied.
prospects of formation of cages and polymers, especially where
There are
(Li2), both exhibiting novel features in pyrazolate
0
ligation (Me pzH ¼ 3,5-dimethylpyrazole; tmeda ¼ N,N,N ,
2
[2b–d,10]
thereare added functionalities.
0
In addition, the compounds
N -tetramethylethane-1,2-diamine). With the less utilised
*
On the auspicious occasion of this special issue, we dedicate this paper to our great friend, mentor, collaborator and colleague Allan H. White. A massive
contributor to Australian chemistry and to this Journal and still number one on the CCDC hit parade.
Journal compilation � CSIRO 2020
www.publish.csiro.au/journals/ajc

B
N. E. Rad et al.
[
Li (Me pz) (OEt ) ] (Li1)
4
2
4
2 4
(i)
[
AlMe (Ph pz)] .1/2THF (Al1)
[Li (Me pz) (tmeda) ] (Li2)
6 2 6 2
2
2
2
R3
(
v)
(ii)
R1
R2
N
N
H
(iv)
(iii)
[
Zn(tBu pz) (tBu pzH) ].1/2THF (Zn1)
[Li (Me pzNO ) (thf) ]n (Li3)
2 2 2 2 2
2
2
2
2
Scheme 1. Synthesis of Li, Al, and Zn pyrazolate complexes by protolysis reactions. All reactions performed at room
1
2
3
temperature. Reagents and conditions: (i) nBuLi/Et
1
2
O, R ¼ R ¼ Me, R ¼ H, yield 51 %; (ii) nBuLi/hexane/tmeda,
1 2 3 1 2
2 2
2
3
R ¼ R ¼ Me, R ¼ H, yield 48 %; (iii) nBuLi/THF, R ¼ R ¼ Me, R ¼ NO
, yield 46 %; (iv) ZnEt
/THF, R ¼ R ¼ tBu,
3
1
2
3
R ¼ H, yield 34 %; (v) AlMe
3
/THF, R ¼ R ¼ Ph, R ¼ H, yield 42 %.
3,5-dimethyl-4-nitropyrazolate (Me pzNO ), a new polymeric
complex [Li (Me pzNO ) (thf) ] (Li3) was obtained, illus-
By using 3,5-dimethyl-4-nitropyrazolate (Me pzNO ), a
2 2
2
2
new polymeric complex [Li (Me pzNO ) (thf) ] (Li3) was
2 2 2 2 2 n
2
2
2 2
2 n
1
trating further the role of ancillary donors in pyrazolate
[
formed (Scheme 1). The H NMR spectrum shows the presence
of resonances at 1.70 and 3.42 ppm attributable to the methylene
H atoms of coordinated THF. The absorptions at 1642 and
2c,d]
ligands.
clear [Zn(tBu pz) (tBu pzH) ].1/2THF (Zn1) was isolated, in
From a protolysis reaction of ZnEt , the mononu-
2
2
2
2
2
[
10,11a]
ꢀ1
contrast to the usual pyrazolate bridged dimers for Zn.
attempts to explore the reactions between AlMe and pyrazole
In
1300 cm in the IR spectrum indicate the presence of NO . The
2
elemental analysis results were consistent with the composition
found in the X-ray crystal structure (see below).
By using ZnEt as the metallating reagent, [Zn(tBu pz) -
3
proligands with different stoichiometric ratios, [AlMe2-
m-Ph pz)] .1/2THF (Al1) was consistently isolated.
(
2
2
2
2
2
(
tBu pzH) ].1/2THF (Zn1) was isolated. The infrared spectrum
2 2
ꢀ1
Results and Discussion
of crystalline Zn1 shows an NH absorption at 3137 cm for the
coordinated tBu pzH. Because of the presence of both tBu pz
and tBu pzH in the structure, two individual set of resonances
Synthesis of Pyrazolate Complexes of Li, Zn, and Al
2
2
2
The Li, Zn, and Al pyrazolate complexes were synthesised by
metalation of a range of pyrazoles (3,5-dimethylpyrazole
1
were observed in the H NMR spectrum. The signals at 1.10 and
5
tively, whereas the resonances at 1.52 and 6.09 ppm are from the
.96 ppm are assigned to the tBu and H4 of tBu pzH respec-
2
(Me pzH), 3,5-dimethyl-4-nitropyrazole (Me pzHNO ), 3,5-
di-tert-butypyrazole (tBu pzH), and 3,5-diphenylpyrazole
2
2
2
2
tBu and H4 of tBu pz. The broad signal at 10.33 ppm is assigned
2
(Ph pzH)) in a variety of solvents (Scheme 1). From n-butyl-
lithium in Et O and tmeda/hexane, complexes [Li (Me pz) -
2
to the N–H hydrogen atoms of tBu pzH. The elemental analysis
2
2
4
2
4
indicates loss of THF of crystallisation from the single-crystal
composition.
From attempts to explore the reactions between AlMe and
(OEt ) ] (Li1) and [Li (Me pz) (tmeda) ] (Li2) were isolated
respectively (Scheme 1).
2 4 6 2 6 2
1
3
The H NMR spectrum of compound Li1 ([Li (Me pz)
4
4
2
3
1
,5-diphenylpyrazole with different stoichiometries (mole ratio
: 1, 1 : 2, 1 : 3 pz : AlMe ), [AlMe (Ph pz)] .1/2THF (Al1)
(
OEt ) ]) shows no NH resonance at d ¼ 10 ppm; hence, the
2
4
3
2
2
2
complete deprotonation of the pyrazole occurred. A triplet at
d ¼ 1.01 ppm and quartet at d ¼ 3.15 ppm arise from coordi-
with bridging Ph pz groups was always obtained. The very
2
ꢀ1
strong band in the IR spectrum at ,679 cm in compound Al1
nated Et O. The IR spectrum is devoid of any NH absorption at
2
[16]
is attributed to an Al–C(Me) stretching absorption.
ꢀ1
The
absence of an NH absorption at 3100–3400 cm confirms the
ꢀ
1
100–3400 cm . The elemental analysis indicates that the
3
four coordinated Et O molecules were lost before analysis could
take place.
2
1
deprotonation of the pyrazole. The H NMR spectrum of
compound Al1 shows resonances at 1.40 and 3.55 ppm, which
are attributed to the lattice THF molecule. The resonance at
Complete deprotonation of the pyrazole in compound Li2
[Li (Me pz) (tmeda) ]) was confirmed by the absence of the
(
6 2 6 2
–
groups of AlMe . Appropriate Ph pz resonances were also
0.66 ppm is attributed to the hydrogen atoms of four methyl
1
NH resonance at d ¼ 10 ppm in the H NMR spectrum. A signal
2
2
at 1.90 ppm is the result of the coincident resonances of the
methyl groups of tmeda and Me pz. The IR spectrum is devoid
observed. The elemental analysis indicated the loss of THF of
crystallisation from the single-crystal composition.
2
ꢀ1
of NH absorption at 3100–3400 cm . The compound repeat-
edly returned poor elemental analyses (consistently low per-
centage of carbon and nitrogen). Problems with microanalyses
of highly reactive compounds is a common occurrence, with a
Structural Discussion
The X-ray crystal structure of the Et O-ligated tetrameric lith-
2
[
15a]
variety of reasons given.
based solely on X-ray and NMR data.
In some cases, characterisation is
ium pyrazolate complex [Li (Me pz) (OEt ) ] (Li1), where the
4
2
4
2 4
[15b–e]
asymmetric unit is made up of two unique [Li(Me pz)(Et O)]
2
2

Lithium, Zinc, and Aluminium Pyrazolates
C
˚
Table 1. Selected bond lengths (A) and angles (8) of Li1
Li(1) environment
Bond length
Li(2) environment
Atom
Atom
Bond length
#
1
N1
N2
N2
O1
2.005(11)
2.146(11)
2.161(11)
2.062(11)
3.240(18)
3.087(16)
N3
2.024(13)
2.144(11)
2.152(12)
2.051(12)
3.062(17)
3.21(2)
#4
N4
N4
#3
#5
O2
Li1#1
#1
#4
#5
Li1–Li1
Li1–Li1
Li2–Li2
Li2–Li2
#2
N1
Bond angles (8)
#1
#2
#3
#3
#4
Li2 –Li2–Li2
#5
#6
#6
Li1 –Li1–Li1
58.35(16)
58.35(16)
63.3(3)
58.40(19)
58.40(19)
63.2(4)
Li1#3
#1
#5
Li2 –Li2–Li2
Li1 –Li1–Li1
Li1#2
#2
Li1 –Li1–Li1
#4
Li2 –Li2–Li2
N2
Li1
Symmetry elements used are: #1¼ –x, –y, z; #2 ¼ –y, x, –z; #3¼ y, –x, –z;
#4¼ y – 1/2, 1/2 – x, 1/2 – z; #5¼ –x, 1 – y, z; #6 ¼ 1/2 – y, 1/2 þ x, 1/2 – z.
L1,2#2
Li#1
O1
Li#3
L1,2#1
Li#2
L1,2
4 2 4 2 4
Fig. 1. X-ray crystal structure of [Li (Me pz) (OEt ) ] (Li1); hydrogen
L1,2#3
Li1
atoms removed for clarity. Symmetry generators are: #1 ¼ –x, –y, z; #2 ¼ –y,
x, –z; #3 ¼ y, –x, –z.
4 2 4 2 4
Fig. 2. The pseudo-cubane type structure of [Li (Me pz) (OEt ) ] (Li1)
#2
#1
#1 #3
#2
(
L ¼ Me
2
pz) (N2 bridges Li1,1 ; N2 bridges Li1 ,1 ; N2 bridges
#
1
#2
#3
#3
Li1 ,1 ; N2 bridges Li1,1 ). Symmetry generators are: #1 ¼ –x, –y, z;
#
2 ¼ –y, x, –z; #3 ¼ y, –x, –z.
monomers, each of which grows to a tetramer, is shown in Fig. 1
(only one unique tetramer involving Li1 is shown; the other is
similar). The structure consists of four lithium ions bridged by
four pyrazolate ligands. The coordination sphere of the lithium
ion is completed by one Et O molecule, resulting in four-
An X-ray crystallographic study of [Li
(Me pz) (tmeda) ]
2 6 2
6
(Li2) shows an unsymmetrical cyclic hexanuclear hexalithium
hexapyrazolate with two tmeda co-ligands (Fig. 3). The six
lithium atoms are connected by six pyrazolate ligands employ-
ing four different binding modes (Table 2). All binding
2
coordinate lithium centres in a pseudo-cubane array.
Each lithium atom has a distorted tetrahedral geometry and
occupies a vertex of the pseudo-cubane structure. One nitrogen
from each pyrazolate ring (N1, along with its symmetry-
generated analogues) coordinates one lithium atom with a
[
2b,21]
1
1
modes have been previously reported.
[
The m-Z :Z
2b]
1
2
1
mode is the most common,
2
m -Z :Z :Z is discussed in the
Introduction and m-Z :Z with the structure of Li1, whereas
m -Z :Z :Z has only once been observed previously, viz. in
3
1
˚
shorter Li–N bond (2.005(11) A) than the other (N2 and its
symmetry-generated partners), which bridges between two
2 2 1
3
[21]
lithium atoms with longer Li–N distances (2.146(11)–
˚
[Na (tBu pz) H].
7 2 6
2
.161(11) A) (Table 1). Li–N(ter) is usually shorter than
Despite the number of different binding modes, more (six)
[2e]
Li–N(br) of the same ligand, but only marginally at the
three estimated standard deviation (e.s.d.) level.
have been observed in [Ce
has some similarity to the above hydride-centred cage
also to the oxide- and hydroxide-centred cages [Na (pz) O]
6
4
(Me
pz)12].
2
The present cage
[21]
and
[9a]
2
1
Thus, all ligands display m-Z :Z binding, a relatively uncom-
8
[2b]
mon coordination mode for pyrazolates,
[9b]
but observed in
[9b]
Sc(Ph pz) ], [Li(Ph pz)(OEt )] , [Li(tBu pz)(tBu pzH)] ,
and [Na
7
(pz)
6
(OH)] (pzH ¼ pyrazole).
[
17]
[9a]
[
[
(
The complex shows great variability in coordination number,
viz. three to six (Table 3). The highest coordination number is
for Li1,6, which have tmeda coordinated as otherwise Li1,6
would be highly exposed on one face. These lithium atoms have
2
6
2
2
2
2
2
2
[
9b]
[18]
Li(t-Bu pz)] ,
2
[Dy (Ph pz) ],
2
[Mo(allyl)(tBu pz)-
2
4
2
6
[
19]
[20]
CO) ] ,
2
[Mg(Cp)(tBu pz)] (CpH ¼ cyclopentadiene),
12
2
2
[
2e]
2
1
and [Ce (Me pz) ]. With solely m-Z :Z binding holding a
4
2
tetranuclear complex together, Li1 is similar to the structure of
9b]
one long and one very long Li–N(Me pz) bond (Table 3). The
2
[
[Li(tBu pz)] ,
whereas the current complex has four coordination.
but the latter has three-coordinate Li atoms,
four-coordinate Li atoms (Li2,3,4) have one long or one very
long bond. Three-coordinate Li5 has only short bonds. These
trends are not unexpected and can also be seen from ,Li–N.
values (Table 3). The largest ,Li–N. value of the four-
coordinate Li atoms is associated with Li3, which appears the
most crowded (Fig. 3).
2
4
The overall structure is a pseudo-cubane type (Fig. 2). The
bridging nitrogen atoms of the 3,5-dimethylpyrazolate and the
lithium atoms form the Li L structure. The Li–Li distances in
4
4
˚
Li1 (3.062 (17)–3.21(2) A) are at the top end of the range
[
9b]
˚
found in [Li(tBu pz)] (2.812(4)–3.095(4) A),
and the
expanded core is attributable to the higher coordination
Complex Li3 crystallised in the monoclinic space group
P2 /n with half the dinuclear unit ([Li (Me pzNO ) (thf) ]
1 2 2 2 2 2
2
4
number in Li1.
(Fig. 4, top; Table 4) within the asymmetric unit. The

D
N. E. Rad et al.
N2
N22
Li2
N62
N61
Li1
N21
N41
N42
Li4
N3
Li5
Li6
N1
Li3
N11
N4
N32
N31
N12
N51
N52
Fig. 3. X-ray crystal structure of [Li
6
(Me
2
pz)
6
(tmeda)
2
] (Li2); hydrogen atoms removed for clarity.
˚
H?N 2.042(3) A, N–H?N 143.748). The presence of
hydrogen bonding was observed in the previously reported
2
Table 2. Binding of Me pz ligands in Li2
[23]
[Zn (Me pz) (Me pzH) ]. Even though the H-bonding involves
two non-coordinating N atoms (of Me pz and Me pzH), the
A
A
2 2 4 2 2
Ligand
Binding mode
Atoms connected
2
2
2
2
1
N(11,12)
N(21,22)
N(31,32)
N(41,42)
N(51,52)
N(61,62)
m
m
3
-Z :Z :Z
Li1,2,3
Li1,2,3
Li3,4
electronic effects may contribute to the similarity of the
Zn–N(tBu pz) and Zn–N(tBu pzH) bond lengths. Unidentate
pyrazolate coordination is quite rare and in this case is enabled
by H-bonding as previously observed in [Nd(Me pz) -
The Zn–N bond lengths in compound Zn1
are close to the similar Zn–N bonds reported in [Zn (Me pz) -
2
1
1
3
-Z :Z :Z
2
2
1
2
m-Z :Z
1
1
m-Z :Z
Li2,5
2
3
2
1
2
2
m
m
3
-Z :Z :Z
Li4,5,6
Li4,5,6
[17]
(
MepzH)py].
1
1
3
-Z :Z :Z
2
2
4
[
23]
˚
(Me pzH) ] (2.025 A).
2 2
A
The sequence of attachment for each binding mode in column 2 corre-
sponds to the sequence of lithium atoms listed in column 3.
Compound Al1 crystallised in the triclinic crystal system,
space group P-1, and is a dimeric molecule with a six-membered
Al N ring and four terminal methyl groups (Fig. 6). The
2
4
structure is comparable with those observed in the pyrazolato
[13]
[Li (Me pzNO ) (thf) ] units form a polymer bridged by
O N groups in an anti-configuration (Fig. 4, bottom). The lithium
2 2 2 2 2
derivatives [Al Me (m-pz) ],
(pz ¼ pyrazolate; earlier iden-
2
4
2
2
1
tified on the basis of H NMR spectroscopy and molecular
1
1
atom is coordinated by two pyrazolate ligands in m-Z :Z fashion
the most common pyrazolate ligation for non-rare earth
[
24]
weight data together with [Al Et (m-pz) ])
and [Al Me -
2 4
2
4
2
[12]
(
[25]
[2b]
(m-tBu pz) ], and higher homologues. Two 3,5-diphenyl-
2
2
complexes), a THF and a nitro oxygen atom giving a coordina-
tion number of four in a tetrahedral coordination geometry.
The two THF molecules in the dinuclear unit are arranged in a
trans fashion (Fig. 4, top). A series of polymeric lanthanoid
complexes having a ligand with a coordinated nitro group (e.g.
o-nitrophenolate) ([(THF) {K(o-O N-C H -O) Ln} ] (Ln ¼ Y,
1 1
pyrazolato groups serve as bridges (m-Z :Z ) between the two
aluminium atoms. The bond lengths (Fig. 6 caption) show no
[13,25]
unusual features compared with related structures.
contrast with structures of alkylaluminium pyrazolates where
both alkyl and pyrazolate groups are bridging.
These
[
6a,b,12]
4
2
6
4
4
4 n
22]
[
Er, Lu); [[K (o-O NC H O) Tb] ] etc.) are known.
2
2
6
4
5
n
Conclusion
The structure of {[Zn(tBu pz) (tBu pzH) ].1/2THF} (Zn1)
2
2
2
2
(
P2 /n, with half of a THF lattice solvate. The Zn metal centre is
Fig. 4) was solved and refined in the monoclinic space group
The successful preparation and characterisation of [Li4-
(Me pz) (OEt ) ] (Li1), [Li (Me pz) (tmeda) ] (Li2), and
1
2
4
2 4
6
2
6
2
coordinated by two unidentate pyrazolate ligands through N2
and N6 and two pyrazole molecules through N3 and N7 in a
tetrahedral array (Fig. 5). The two Zn–N(2) and Zn–N(6) bonds
are similar (within 3 e.s.d.) to the other two Zn–N bonds even
though the two coordinated pyrazolate ions are charged while
the other two ligands are neutral.
[Li
2
(Me pzNO ) (thf) ] (Li3) provide advances in lithium
2 2 2 2 n
pyrazolate chemistry. Li1 is unusual in that the pseudo-cubane
2
structure has only the rare m-Z :Z binding mode. [Li6-
(Me pz) (tmeda) ] (Li2) is the first hexanuclear lithium pyr-
azolate complex, with the lithium atoms having three different
coordination numbers. There are also four different bridging
modes m-Z :Z , m-Z :Z , m -Z :Z :Z , and m -Z :Z :Z . From
1
2
6
2
1
1
2
1
1
2
1
2
2
1
Hydrogen bonding occurs between the two pyrazole molecules
and the free pyrazolate nitrogen atoms N5 and N1 (N(8)–H(8) ?
3
3
3,5-dimethyl-4-nitropyrazolate (Me pzNO ), a new 2-D poly-
2
meric complex [Li (Me pzNO ) (thf) ] (Li3) was obtained
2 2 2 2 2 n
2
˚
N(1), H?N 2.051(4) A, N–H?N 144.818 and N(4)–H(4) ꢁꢁN(5),

Lithium, Zinc, and Aluminium Pyrazolates
E
˚
Table 3. Selected bond lengths (A) and angles (8) of Li2
Li1
Bond length
Li2
Li3
Li4
Li5
Li6
Atom
Atom
Bond length
Atom
Bond length
Atom
Bond length
Atom
Bond length
Atom
Bond length
N1
2.111(7)
2.111(7)
2.060(7)
2.646(7)
2.122(7)
2.398(7)
2.24 (2.31)
N41
N11
N12
N22
1.979(7)
2.051(7)
2.486(7)
1.982(7)
N21
N12
N31
N32
2.004(7)
1.995(7)
1.943(7)
2.650(7)
N32
N51
N52
N61
1.965(7)
2.318(7)
2.031(7)
1.989(7)
N42
N51
N62
1.971(7)
2.013(7)
2.031(7)
N3
N4
2.114(7)
2.120(7)
2.719(7)
2.047(7)
2.374(7)
2.146(7)
N2
N11
N51
N52
N61
N62
N12
N21
N22
A
A
Ave (Li–N)
Bond angles (8)
N(1)–Li(1)–N(2) 87.3(3)
2.12
2.15
2.08
2.01
2.25 (2.32)
N(21)–Li(1)–N(22) 35.51(15)
N(51)–Li(6)–N(52) 30.31(8)
N(32)–Li(4)–N(61) 126.05(6)
N(51)–Li(5)–N(62) 104.32(12)
N(11)–Li(1)–N(12) 31.56(14)
N(61)–Li(6)–N(62) 35.59(8)
N(42)–Li(5)–N(62) 130.72(3)
N(11)–Li(2)–N(12) 34.23(4)
N(51)–Li(4)–N(52) 36.95(4)
N(42)–Li(5)–N(51) 124.74(12)
A
2
Li–N(Me pz) only.
in which [Li (Me pzNO ) (thf) ] units are bridged by the
2
cooling bath then was removed and reaction mixture was stirred
at room temperature (rt) for 1 h. Another portion of concentrated
sulfuric acid (17 mL, 96%) then was added dropwise at a rate to
maintain the temperature below 708C. The solution then was
heated at 708C for 3 h, cooled to room temperature, and left
overnight. The next day, the reaction mixture was poured into
400 g of crushed ice, carefully neutralised first with 40% aqueous
NaOH solution and thenbyaddition of solidNa CO to pH8–8.5,
2
2 2
2
O N group in an anti-configuration. A new mononuclear pyr-
2
azolatozinc derivative ([Zn(tBu pz) (tBu pzH) ].1/2THF (Zn1))
2
2
2
2
with two unidentate pyrazolate and two neutral tBu pzH ligands
2
was obtained. Hydrogen bonding occurs between the pyrazole
and pyrazolate donors. The dimeric compound [AlMe2-
(Ph pz)] .1/2THF (Al1), prepared by reaction of AlMe with
Ph pzH in several ratios, features two 3,5-diphenylpyrazolato
2
2
3
2
2
3
groups bridging the two aluminium atoms, and terminal methyl
groups.
and extracted with CH Cl (3ꢂ 100 mL). The combined organic
2
2
phase was washed with brine (2ꢂ 50mL), dried over MgSO ,
4
filtered, and evaporated under reduced pressure to afford 3,5-
dimethyl-4-nitro-1H-pyrazole as a white solid. Yield 17.8g
Experimental
[28]
79 %); mp 125–1268C from hexanes (lit. 126–1268C ).
(
d (CDCl , 298K) 11.09 (broad s, 1H, NH), 2.66 (s, 6H, CH ).
General
H
3
3
Synthetic operations were carried out under an inert atmosphere
of dry nitrogen using standard Schlenk and vacuum line tech-
niques. All solvents were freshly distilled over sodium
or sodium/benzophenone before use. 3,5-Dimethylpyrazole
d (CDCl , 298K) 143.41, 143.35, 129.09, 12.83.
C
3
[
Li (Me pz) (Et O) ] (Li1)
4 2 4 2 4
nBuLi (1.6 mL of a 2.5 M solution in hexane, 4.0 mmol) was added
by syringe to a stirring solution of Me pzH (0.40 g, 4.0 mmol) in
Et O (20 mL) using a Schlenk line. After 1 day stirring, the solution
(Me pzH) was purchased from Sigma–Aldrich and 3,5-diphe-
nylpyrazole (Ph pzH) and 3,5-di-tert-butylpyrazole (tBu pzH)
2
2
2
2
[
were prepared by literature methods, while Me pzNO H was
26]
2
2
2
was concentrated to ,10 mL, and cooled overnight, causing
synthesised according to a modified published procedure
[27]
the formation of colourless crystals. Yield 0.36 g (51 %). n
(
(
below).
nBuLi), and diethylzinc (ZnEt ) were purchased from Aldrich
Trimethylaluminium (AlMe3), n-butyllithium
max
ꢀ
1
crystal oil)/cm 1515 (s), 1316 (m), 1260 (w), 1152 (m), 1076 (m),
(
2
1
6
017 (s), 966 (m), 727 (vw), 843 (w), 774 (m), 737 (s), 691 (vw),
ꢀ
and used as received. IR spectra were obtained from Nujol mulls
or in paritone oil used for mounting crystals for the region 4000–
1
68 (vw), 656 cm (m). d (C D , 303.2 K) 1.01 (t, 24 H, CH
3
H
6
6
ꢀ
1
Et O), 2.12 (s, 24 H, CH (Me pz)), 3.15 (q, 16 H, CH Et O), 5.89
2
4
spectrometer. The H NMR spectra were recorded with a Bruker
00 cm
with a Nicolet-Nexus Fourier-transform (FT)-IR
1
3
2
2
2
(s, 4 H, H4–Me pz). Found: C 56.65, H 8.00, N 24.22.
2
C H Li N O (M 704.24 g mol ) requires C 61.35, H 9.72,
ꢀ
1
TM
Ascend 400 (400 MHz) instrument using dry degassed deu-
36 68
4 8 4
N 15.90 %; C H Li N (loss of four Et O molecules)
2
terobenzene (C D ) as solvent, and resonances were referenced
6
20 28
1
4
8
6
ꢀ
1
(407.76 g mol ) requires C 58.85, H 6.86, N 27.46 %.
to the residual H resonances of the deuterated solvent or with a
Bruker AM-300 instrument. Elemental analyses (C, H, N) were
performed by the Micro Analytical Laboratory, Science Centre,
London Metropolitan University, England.
[Li (Me pz) (tmeda) ] (Li2)
6
2
6
2
nBuLi (1.6mL of a 2.5 M solution in hexane, 4.0 mmol)
was added by syringe to a stirring solution of Me pzH
2
3
,5-Dimethyl-4-nitro-1H-pyrazole (Me pzNO H)
2 2
(0.40 g, 4.0 mmol) in hexane and tmeda (4mmol, 0.6 mL)
(tmeda : Me pzH 1 : 1) (20 mL) using a Schlenk line. After 1 day
This pyrazole was synthesised by our original adaptation of a
27]
2
[
published procedure
3
as follows:
,5-Dimethylpyrazole (15.0 g, 156 mmol) was added to con-
stirring, the solution was concentrated to ,10mL, and cooled
overnight, causing the formation of colourless crystals. Yield
ꢀ1
centrated sulfuric acid (30 mL, 96 %) in a small portions with
continuous stirring and external cooling (ice-water), resulting in a
clear solution. Nitric acid (18 mL, 70 %) was added dropwise to a
magnetically stirred solution of pyrazole in H SO at such a rate
0.27g (48 %). nmax (crystal oil)/cm 3098(m), 2716 (m), 1562
(w), 1378(vs), 1378(vs), 1316(vs), 1289(vs), 1246(s), 1180(m),
1157 (s), 1129 (s), 1098 (m), 1067 (s), 1019 (vs), 948 (vs), 881
(w), 828 (s), 766 (vs), 737 (vs), 688 (m), 663 (m). dH (C D ,
2
4
6 6
to maintain the temperature within the range of 5–108C. The
303.2 K) 1.90 (m, 60H, CH tmeda and Me pz), 2.22 (s, 8 H, CH
3 2 2

F
N. E. Rad et al.
O1#
N3#
O2#
N2#
N1#
O3
Li1#
N1
N2
Li1
O3#
N3
O2
O1
Fig. 4. X-ray crystal structure of [Li
2
(Me pzNO
2
2
)
2
2 n
(thf) ] (Li3). Top: showing the dinuclear repeating unit composed of two asymmetric units.
2 5 3 6 2 2 2 n
Symmetry equivalent used: # 1 – x, 1 – y, 2 – z. Bottom: the polymeric [Li (C N H O ) (thf) ] . For both figures, ellipsoids are shown at 50 %
probability; H atoms removed for clarity.
(
tmeda)), 5.89 (s, 6 H, H4–Me pz). Repeated attempts at ele-
2
Schlenk line. After 1 day stirring, the solution was concentrated
to ,5 mL, and cooled for 4 days, during which red crystals
mental analysis to obtain C, H, and N data gave variable results
even though single crystals were submitted for analysis.
ꢀ
1
formed. Yield 0.14 g (46 %). nmax (crystal oil)/cm 1642 (m),
1
(vw), 770 (m), 722 (s). dH (C D , 303.2 K) 1.70 (m, 8 H,
529 (m), 1300 (m), 1163 (s), 1046 (m), 977 (m), 891 (m), 823
[
Li (Me pzNO ) (thf) ] (Li3)
2 2 2 2 2 n
6
6
nBuLi (0.56 mL of a 2.5 M solution in hexane, 1.4 mmol)
was added by syringe to a stirring solution of 3,5-dimethyl-
b-CH (thf)), 2.28 (s, 12 H, CH (pz)), 3.42 (m, 8 H, a-CH (thf)).
2
3
2
Found: C 49.17, H 6.50, N 19.26. C H Li N O (M 438.34 g
18 28 2 6 6
ꢀ
1
mol ) requires: C 49.32, H 6.43, N 19.17 %.
4
-nitropyrazole (0.20 g, 1.4 mmol) in THF (20 mL) using a

Lithium, Zinc, and Aluminium Pyrazolates
G
˚
Table 4. Selected bond lengths (A) and angles (8) for Li3; symmetry equivalents used: #1 5 1 – x, 1 – y, 2 – z;
2 5 –1/2 – x, –1/2 1 y, 3/2 – z
#
Bond lengths
Li(1)–O(3)
Li(1)–N(1)
#
2
1.995(11)
2.043(11)
2.018(13)
Li(1)–O(1)
2.002(11)
2.018(13)
3.525(13)
#1
Li(1) –N(2)
#1
#1
Li(1)–N(2)
Li(1) –Li(1)
Bond angles
Li(1)–N(1)–N(2)
O(2)–N(3)–O(1)
N(1)–N(2)- Li(1)
120.8(6)
121.0(6)
121.0(6)
O(3)–Li(1)–N(1)
N(1)–Li(1)–N(2)
106.9(5)
115.5(5)
#1
#1
C2
C3
C1
N12
N11
A11
N3
N4
C33
N2
C34
C31
N1
Zn1
A12
N6
N5
C32
N22
C18
N21
N8
N7
C16
C17
2 2 2
Fig. 6. The X-ray crystal structure of {[AlMe (Ph pz)] .1/2THF} (Al1);
˚
hydrogen atoms removed for clarity. Selected bond lengths (A) and angles (8):
Al(11)–N(11) 1.9581(15), Al(11)–N(21) 1.9514(16), Al(11)–C(31)
Fig. 5. The X-ray crystal structure of {[Zn(tBu
2
pz)
Zn1); H atoms removed for clarity. Selected bond lengths (A) and angles
8): Zn(1)–N(2) 2.040(4), Zn(1)–N(3) 2.028(4), Zn(1)–N(6) 2.019(4),
2 2 2
(tBu pzH) ].1/2THF}
˚
(
(
1
.9714(18), Al(11)–C(32) 1.969(2), Al(21)–N(12) 1.9627(16), Al(21)–
N(22) 1.9631(16), Al(12)–C(33) 1.9700(19), Al(21)–C(34) 1.9772(17);
N(11)–Al(11)–N(21) 102.50(2), N(12)–Al(21)–N(22) 102.54(7), C(31)–
Al(1)–C(32) 125.10(8), C(33)–Al(21)–C(34) 125.35(9).
Zn(1)–N(7) 2.040(5); N(2)–Zn(1)–N(7) 110.62(16), N(6)–Zn(1)–N(3)
09.45(16), N(7)–Zn(1)–N(6) 106.23(18), N(3)–Zn(1)–N(2) 106.19(18),
1
N(3)–Zn(1)–N(7) 113.16(18), N(6)–Zn(1)–N(2) 111.28(17), H(1)–N(1)–
N(2) 125.75(8), H(8)–N(8)–N(7) 110.72(8).
slowly. Colourless crystalline product was obtained after 4 days
and all characterisation was performed on the crystalline
compound. Yield 0.10 g (42 %). nmax (Nujol)/cm 2725(m),
1575(w), 1543 (m), 1302(s), 1197(s), 1157 (m), 1109 (m), 1073 (m),
1008 (m), 967 (m), 917 (m), 869 (vw), 845 (vw), 808 (m),
ꢀ1
[
Zn(tBu pz) (tBu pzH) ].1/2THF (Zn1)
2 2 2 2
ZnEt (0.12 mL of a 15 % w/w solution in toluene; 0.50 mmol) was
2
added by syringe to a stirring solution of tBu pzH (0.20 g,
2
ꢀ
1
1
.0 mmol) in THF (20 mL) using a Schlenk line. After 1 day stir-
ring, the solution was concentrated to ,5 mL, and cooled for
week, resulting in the formation of colourless crystals. Yield
759 (vs), 721 (vs), 697 cm (vs). d
(s, 12 H, AlMe ), 1.40 (m, 2 H, b-CH
a-CH (thf)), 6.26 (s, 2 H, 4-H (Ph pz)), 7.03 (br, m, 12 H, m-,
p-H (Ph pz)), 7.42 (br m, 8 H, o-H (Ph pz)). Found: C 73.51, H
6.06, N 12.85. C34
H
(C
6 6
D , 303.2 K) –0.66
(thf)), 3.55 (m, 2 H,
2
2
1
2
2
ꢀ1
0
.070 g (34 %). nmax (crystal oil)/cm 3137(m), 1571 (m), 1290 (s),
2
2
1
8
1
5
1
204 (m), 1133 (m), 1117 (w), 1083 (m), 1016 (m), 976 (w), 916 (w),
H
34Al
2
N
4
(loss of 1/2 THF molecule of
ꢀ
1
01 (m), 782 (m), 725 (s), 629 cm (w). d (C D , 303.2 K)
ꢀ1
crystallisation) (M 552.20 g mol ) requires: C 73.94, H 6.20,
N 10.14 %. Other stoichiometries, 1 : 1, 1 : 2, did not affect the
outcome. Low yields of crystals were obtained in each case
H
6 6
.10 (s, 36 H, tBu (tBu pzH)), 1.52 (s, 36 H, tBu (tBu pz)),
2
2
.96 (s, 2 H, H4, tBu pzH), 6.09 ppm (s, 2 H, H4, tBu pz),
2
2
1
0.33 (br s, 2 H, H4, tBu pzH). Found: C 68.50, H 8.76, and
2
( H NMR identification).
N 14.29. C H N Zn (loss of 1/2 THF molecule of crystallisation)
(
4
4 78 8
ꢀ
1
M 783.38 g mol ) requires: C 67.39, H 9.95, N 14.28 %.
X-Ray Crystallography
Single crystals covered with viscous hydrocarbon oil were
mounted on glass fibres or loops. Data were obtained at –1738C
(100K) on the MX1: Macromolecular Crystallography beamline
at the Australian Synchrotron, Victoria, Australia (compounds
Li2 and Al1), or at 258C (298(2) K) on a Bruker APEX II CCD
diffractometer (compounds Li1, Li3, Zn1) equipped with
[
AlMe (Ph pz)] .1/2THF (Al1)
2
2
2
Using a Schlenk line, a solution of AlMe (0.15 mL of a 2.0 M
3
solution in toluene, 0.30 mmol) was added dropwise to a sus-
pension of Ph pzH ligand (0.20 g, 0.90 mmol) in 20 mL THF
under vigorous stirring. Instant gas formation was observed. The
clear solution was stirred overnight at ambient temperature, and
then evaporated (under vacuum) to less than 5 mL and cooled
2
˚
graphite-monochromated MoKa radiation (l 0.71073 A). Data
collection and integration on the MX1: Macromolecular

H
N. E. Rad et al.
[29]
Crystallography beamline were accomplished using Blu-Ice.
The structures were solved using SHELXS or SHELXT and
work was conducted using the MX1 beamline at the Australian Synchrotron,
[32]
which is part of ANSTO.
I.V.T. is grateful to the Russian Science
2
refined by full-matrix least-squares on all F data using
Foundation (project no. 19–13–00272) for financial support of his part of the
work.
[30]
SHELX2014
[31]
interface.
in conjunction with the X-Seed graphical user
All hydrogen atoms were placed in calculated
References
positions using the riding model. Data collection and refinement
details are collated below.
[1] S. Fustero, M. S a´ nchez-Rosell o´ , P. Barrio, A. Sim o´ n-Fuentes, Chem.
Rev. 2011, 111, 6984. doi:10.1021/CR2000459
[2] (a) G. La Monica, G. A. Ardizzoia, in Progress in Inorganic Chemistry
(Ed. F. A. Cotton) 1997, Vol. 46, pp. 151–238 (John Wiley & Sons,
Inc.: New York, NY).
[
Li (Me pz) (Et O) ] (Li1): C H N O Li , (M 704.74
4
4
ꢀ
2
4
2
4
36 68
8
4
1
˚
g mol ), tetragonal, I-4c2 (no. 120), a ¼ b ¼ 15.598(3) A,
3
˚
˚
c 37.861(8) A, a ¼ b ¼ g ¼ 908; V 9211(4) A ; T 298(2) K;
ꢀ
1
ꢀ3
Z ¼ 8, Z’ ¼ 2, m(MoKa) 0.065 mm ; D 1.016 g cm , 9537
calc
(
(
b) M. A. Halcrow, Dalton Trans. 2009, 2059. doi:10.1039/B815577A
c) J. Klingele, S. Dechert, F. Meyer, Coord. Chem. Rev. 2009, 253,
reflections measured, (8.2628 # 2y # 49.988), 3793 unique
(
Rint ¼ 0.1230), which were used in all calculations. The final
2698. doi:10.1016/J.CCR.2009.03.026
wR was 0.1974 (all data) and R was 0.0686 (I . 2s(I)).
[Li (Me pz) (tmeda) ] (Li2): C H Li N (M 844.81
g mol ): orthorhombic, space group P2 2 2 (no. 19),
2
1
(d) M. Viciano-Chumillas, S. Tanase, L. J. de Jongh, J. Reedijk, Eur.
J. Inorg. Chem. 2010, 3403. doi:10.1002/EJIC.201000412
(e) D. Werner, V. Bayer, N. E. Rad, P. C. Junk, G. B. Deacon,
R. Anwander, Dalton Trans. 2018, 5952. doi:10.1039/C8DT00338F
[3] (a) W. Zheng, M. J. Heeg, C. H. Winter, Eur. J. Inorg. Chem. 2004,
2652. doi:10.1002/EJIC.200400025
6 2 6 2 42 74 6 16
ꢀ
1
1
1 1
˚
˚
˚
a 13.296(3) A, b 13.384(3) A, c 29.598(6) A; a ¼ b ¼ g ¼ 908;
3
˚
V 5267.1(18) A ; Z ¼ 4, Z’ ¼ 1; T 100(2) K; m(MoKa)
ꢀ
1
.065 mm ; D
ꢀ3
1.065 g cm , 56913 reflections measured
calc
0
(
(
b) J. Hitzbleck, A. T. O’Brien, C. M. Forsyth, G. B. Deacon,
3.348 # 2y # 52.7448), 10661 unique (Rint ¼ 0.0379), which
K. Ruhlandt-Senge, Chem. – Eur. J. 2004, 10, 3315. doi:10.1002/
CHEM.200400076
were used in all calculations. The final wR was 0.1670 (all data)
2
and R was 0.0630 (I . 2s(I)).
1
(
c) D. Pfeiffer, M. J. Heeg, C. H. Winter, Angew. Chem. Int. Ed. 1998,
[
Li (Me pzNO ) (thf) ]
(Li3):
M 438.34 g mol ): monoclinic, space group P2 /n (no. 14), a
C H Li N O
18 28 2 6 6
2
2
2 2
1
2 n
37, 2517. doi:10.1002/(SICI)1521-3773(19981002)37:18,2517::
AID-ANIE2517.3.0.CO;2-1
[4] (a) W. Zheng, N. C. M o¨ sch-Zanetti, T. Blunck, H. W. Roesky,
M. Noltemeyer, H.-G. Schmidt, Organometallics 2001, 20, 3299.
doi:10.1021/OM010271Y
ꢀ
(
1
˚
.2926(5) A, b 12.8207(8) A, c 11.3992(6) A; b 98.151(2)8;
˚
˚
8
3
˚
V 1199.68(12) A ; Z¼ 2, Z’ ¼ 0.5; T 298 K; m(MoKa)
ꢀ1
ꢀ3
1.213 g cm ; 3112 reflections measured
calc
0
.090 mm ; D
(
b) G. B. Deacon, E. E. Delbridge, C. M. Forsyth, P. C. Junk, B. W.
(
4.8088 # 2y # 49.6268), 853 unique (R ¼ 0.0263), which were
int
Skelton, A. H. White, Aust. J. Chem. 1999, 52, 733. doi:10.1071/
CH99068
5] W. Zheng, A. Stasch, J. Prust, H. W. Roesky, F. Cimpoesu,
M. Noltemeyer, H.-G. Schmidt, Angew. Chem. Int. Ed. 2001, 40, 3461.
doi:10.1002/1521-3773(20010917)40:18,3461::AID-ANIE3461.3.
used in all calculations. The final wR was 0.2182 (all data) and R
2 1
was 0.0674 (I . 2s(I)).
Zn(tBu pz) (tBu pzH) ].1/2THF (Zn1): C H N O0.5Zn
[
[
2
2
2
2
46 82 8
ꢀ
M 820.56 g mol ): monoclinic, space group P2 /n (no. 14),
1
1
(
˚
˚
˚
a 10.954(2) A, b 33.040(6) A, c 14.287(2) A; a 908, b 103.954(9)8,
0
.CO;2-3
3
˚
g 908; V 5017.9(16) A ; Z ¼ 4, Z’ ¼ 1; T 298(2) K; m(MoKa)
[
6] (a) Z. Yu, M. J. Heeg, C. H. Winter, Chem. Commun. 2001, 353.
doi:10.1039/B008047K
(b) Z. Yu, J. M. Wittbrodt, M. J. Heeg, H. B. Schlegel, C. H. Winter,
ꢀ
1
.523 mm ; D
ꢀ3
1.008 g cm ; 42288 reflections measured
calc
0
(
2.4668 # 2y # 49.9968), 8805 unique (Rint ¼ 0.1251), which
were used in all calculations. The final wR was 0.2826 (all data)
2
J. Am. Chem. Soc. 2000, 122, 9338. doi:10.1021/JA001822Z
(
c) Z. Yu, J. M. Wittbrodt, A. Xia, M. J. Heeg, H. B. Schlegel, C. H.
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1
Winter, Organometallics 2001, 20, 4301. doi:10.1021/OM010531B
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[
AlMe (Ph pz)] .1/2THF
(Al1):
M 588.66 g mol ): triclinic, space group P-1 (no. 2),
C H Al N O
36 38 2 4 0.5
2
2
2
ꢀ
1
(
˚
˚
˚
a 10.522(2) A, b 11.172(2) A, c 14.019(3) A; a 85.63(3)8,
[
3
˚
b 82.31(3)8, g79.68(3)8; V 1604.4(6) A ; Z¼ 2, Z’ ¼ 1; T100(2) K;
White, J. Chem. Soc., Dalton Trans. 2000, 745. doi:10.1039/A909048G
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ꢀ
1
ꢀ3
m(MoKa) 0.123 mm ; D
1.219 g cm ; 32933 reflections
calc
measured (2.9368 # 2y # 63.758); 8790 unique (Rint ¼ 0.0298),
Chem. Asian J. 2007, 2, 539. doi:10.1002/ASIA.200700005
(b) S.- A´ . Cort e´ s-Llamas, R. Hern a´ ndez-Lamoneda, M.- A´ . Vel a´ zquez-
which were used in all calculations. The final wR was 0.1371
2
(
all data) and R was 0.0470 (I . 2s(I)).
Carmona, M.-A. Mu n˜ oz-Hern a´ ndez, R. A. Toscano, Inorg. Chem.
1
2006, 45, 286. doi:10.1021/IC051294Y
(c) M.-A. Velazquez-Carmona, A.-J. Metta-Magana, S.-A. Cortes-
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Llamas, V. Montrel-Palma, M.-A. Munoz-Hernandez, Polyhedron
The crystal structure data have been deposited with the
Cambridge Crystallographic Data Centre (CCDC): reference
numbers CCDC 1948163 for compound Li1, 1948164 for com-
pound Li2, 1948165 for compound Li3, 1948166 for compound
Zn1, and 1948167 for compound Al1. These data can be obtained
free of charge from the CCDC via http://www.ccdc.cam.ac.uk/
datarequest/cif.
2
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