Combining organometallic and Werner-type coordination sites in highly preorganized heterobimetallic systems

Article abstract of DOI:10.1016/S0022-328X(01)01298-0

A first example of a novel class of preorganized bimetallic complexes is reported, in which both an organometallic CpMn(CO)₂ fragment and a classical Werner-type coordination site are arranged in close proximity by means of a bridging pyrazolat

Full text of DOI:10.1016/S0022-328X(01)01298-0

Journal of Organometallic Chemistry 641 (2002) 113–120
www.elsevier.com/locate/jorganchem
Combining organometallic and Werner-type coordination sites in
highly preorganized heterobimetallic systems
Jens C. Ro¨der a, Franc Meyer a,*, Rainer F. Winter b, Elisabeth Kaifer a
a Anorganisch-Chemisches Institut der Uni6ersita¨t Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
b Institut fu¨r Anorganische Chemie der Uni6ersita¨t Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
Received 18 June 2001; accepted 10 September 2001
Dedicated to Prof. Dr Rolf Gleiter on the occasion of his 65th birthday
Abstract
A first example of a novel class of preorganized bimetallic complexes is reported, in which both an organometallic CpMn(CO)2
fragment and a classical Werner-type coordination site are arranged in close proximity by means of a bridging pyrazolate. The
synthetic route starts from N-protected bis(chloromethyl)pyrazole and involves sequential attachment of the manganese part and
the chelating N-donor compartment, bis(pyridylmethyl)amine, at the different sides of the ligand backbone. Pyrazole binding to
the manganese(I) is achieved by photoinduced substitution of CO, and the adjacent N4-coordination pocket is suited to
accommodate a second metal ion. The heterodinuclear MnZn complex 4 is characterized crystallographically and its redox
chemistry investigated by spectroelectrochemical methods. © 2002 Elsevier Science B.V. All rights reserved.
Keywords: Bridging ligands; N-functionalized cyclopentadienyl ligands; Manganese; Zinc; Bimetallic complexes
1. Introduction
two Cp units acts both as an intramolecular N-donor
and as a bridging unit spanning two-metal ions [5].
Complexes of cyclopentadienyl (Cp) ligands bearing
functional amino or amido side chains are receiving
enormous attention in present organometallic chemistry
[1,2]. While the donor substituent tethered to the Cp
moiety might serve an intramolecular function, e.g.
acting as a (sometimes hemilabile) chelate donor in
generic type A complexes (Scheme 1) [3,4], it may also
serve an intermolecular function, e.g. by anchoring to a
solid support or providing solubility [3]. It suggests
itself to also consider the donor substituent connected
to the Cp ring as a bridging group in dinuclear Cp-
complexes, in which the two proximate metal ions are
well preorganized for cooperative action. With this
intention in mind we recently put forward a novel
bimetallic approach B where a pyrazolate group linking
* Corresponding author. Present address: Institut fu¨r Anorganische
Chemie, Universita¨t Go¨ttingen, Tammannstr. 4, D-37077 Go¨ttingen,
Germany. Tel.: +49-551-393012 +49-6221-54-8315; fax: +49-6221-
54-5707.
Scheme 1.
E-mail address: franc.meyer@urz.uni-heidelberg.de (F. Meyer).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01298-0

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J.C. Ro¨der et al. / Journal of Organometallic Chemistry 641 (2002) 113–120
Fig. 1. View of the molecular structure of 2. In the interests of clarity
,
all hydrogen atoms have been omitted. Selected atom distances (A)
and angles (°): N1ꢀN2, 1.368(2); O1ꢀC1, 1.158(3); O2ꢀC2, 1.150(3);
O3ꢀC3, 1.142(3); Mn1ꢀC2, 1.786(3); Mn1ꢀC2, 1.790(3); Mn1ꢀC3,
1.797(3); Mn1ꢀC4, 2.146(2); Mn1ꢀC5, 2.146(3); Mn1ꢀC6, 2.137(3);
Mn1ꢀC7, 2.117(3); Mn1ꢀC8, 2.136(3); C2ꢀMn1ꢀC1, 93.3(2);
C2ꢀMn1ꢀC3, 88.7(2), C1ꢀMn1ꢀC3, 92.7(2).
ganized bimetallic array. The present contribution is a
report on the synthesis and characterization of a first
type E heterobimetallic complex.
2. Results and discussion
The crucial first step of the synthetic route that
finally led to type E bimetallic systems was found
adventitiously when we tried to scout a new access to
type B compounds. N-protected bis(chloromethyl)-
pyrazole (1) (Scheme 2) [5] appeared as a suitable
starting material for the synthesis of multidentate lig-
ands for type B complexes. However, while indenyl- or
fluorenyl side arms could readily be introduced via
nucleophilic substitution reactions [5], this synthetic
route proved unsuited for parent Cp−, in which case
predominant formation of polymeric material was ob-
served. We next employed CpMn(CO)3 as a ‘protected’
form of Cp, i.e. we set out to prepare the desired type
B system directly as the metal complex. Treatment of 1
with lithiated CpMn(CO)3 did not lead to any observ-
able reaction, but a palladium-catalyzed cross coupling
protocol developed recently [10] turned out to be more
successful. It involves transmetallation of the lithiated
Cp compound to the zinc derivative and the use of a
Pd(PPh3)2 catalyst [11] according to the procedure out-
lined in Scheme 2. The monosubstitution product 2 was
isolated in good yield and fully characterized. Introduc-
tion of a second CpMn(CO)3 moiety could not be
achieved starting from 1, even after extensive variation
of the reaction conditions [12].
Scheme 2.
In a certain way this concept arises from previous
investigations dealing with the functional principles of
natural metalloenzymes that contain di- or oligonuclear
active sites. For such bioinorganic systems it is well
known that cooperativity of two adjacent metal ions
enables very particular and efficient transformations of
small substrate molecules [6]. The general strategy out-
lined in Scheme 1, i.e. the formal coupling of two
N-containing ligand compartments via a functionalized
pyrazolate to constitute a preorganized dinuclear scaf-
fold, has indeed successfully been employed for achiev-
ing cooperative effects in biomimetic coordination
compounds when using all-Werner-type donor sets (C
and D) [7,8]. Accordingly, type B systems are expected
to give rise to some novel organometallic chemistry
where two adjacent metal ions work in concert [5,9]. A
further extension of this chemistry is the combination
of each one type A and one type C subunit in unsym-
metrical dinuclear systems E, i.e. the assembly of both
Werner-type and organometallic fragments in a preor-
The regiochemistry of the substitution reaction lead-
ing to 2 was elucidated by a crystallographic analysis of
single crystals grown from a CH2Cl2–light petroleum
solution. The structure of 2 is depicted in Fig. 1; all

J.C. Ro¨der et al. / Journal of Organometallic Chemistry 641 (2002) 113–120
115
treatment with acid. The resulting compound 3 pro-
vides a tripodal tetradentate N4 coordination pocket
next to an organometallic fragment, where the former
should be suited to accommodate a variety of different
metal ions.
molecular parameters are as expected. Substitution has
obviously occurred in a selective manner within the side
arm next to the thp protecting group. At this point we
can only speculate about the reasons for the observed
regiochemistry. While it is tempting to assume an-
chimeric assistance of the thp–oxygen atom to be re-
sponsible for facilitating nucleophilic substitution on
that particular side of the difunctionalized starting ma-
terial, other (electronic) effects cannot be fully
excluded.
Sole isolation of the monosubstitution product 2
identifies this approach as a dead end with respect to
the sought-after type B systems. However, the remain-
ing reactive Cl site in 2 now enables the attachment of
other coordination compartments. This does in fact
open access to novel unsymmetrical bimetallic type E
complexes, as exemplified here by the synthesis of com-
pound 3 bearing a chelating di(2-picolyl)amine donor
side arm (Scheme 2). Deprotection of the primary
thp-containing product (3thp) is readily achieved by
Photolability of one CO ligand in CpMn(CO)3 and
its derivatives is well established [13]. Accordingly, pho-
toinduced CO substitution in 3 leads to intramolecular
N-coordination of the pyrazote heterocycle, and subse-
quent deprotonation and treatment with ZnCl2 affords
the heterobimetallic complex 4. The composition of the
pale yellow complex 4 was initially deduced from spec-
troscopic evidence and from a high resolution mass
spectrum showing a signal around m/z=567 with an
isotopic distribution pattern corresponding to the
molecular ion 4+. While 2, 3thp and 3 all show an IR
spectroscopic pattern in the CO stretching region that is
typical for a CpMn(CO)3 unit (i.e. a sharp band at
2013–2023 cm−1 (A1 mode) and a broad band of
higher intensity at 1922–1917 cm−1 (E mode); see
Table 1) [14], a significant shift to lower wavenumbers
in 4 (two sharp bands at 1897 and 1820 cm−1 of almost
equal intensity) is indicative of CO replacement by the
pyrazolate and formation of a CpMn(CO)2 fragment.
The anticipated constitution of 4 could be confirmed by
an X-ray crystallographic analysis of single crystals
obtained from a saturated CH2Cl2 solution. The molec-
ular structure of 4 is depicted in Fig. 2 together with
selected atom distances and bond angles.
Table 1
IR absorptions in the CO stretching range; values in cm−1
a
2
2023
2014
2013
1897
1910
2041
1921
1922
1917
1820
1835
1964
3thp b
3 b
4 a
4 c
4+ c
In 4, the pyrazolate bridge spans the CpMn(CO)2
a KBr pellets.
,
fragment and the zinc(II) ion [d(Mn···Zn=4.152 A)]
b Film.
with both metal ions located roughly within the plane
c Dichloroethane solution.
defined by the pyrazolate heterocycle [out of the plane
,
,
by 0.096 A (Zn) and 0.189 A (Mn)]. The N4 coordina-
tion compartment nesting the zinc(II) ion is reminiscent
of the well-known mononucleating tris(2-pyridyl-
methyl)amine (tmpa) systems. However, while mononu-
clear zinc(II) chloride complexes of tmpa-type ligands
usually adopt a trigonal-bipyramidal (TB-5) structure
with the bridgehead N atom and the Cl coligand in the
axial positions [15,16], the zinc coordination sphere in 4
is severely distorted towards a square-pyramide (SPY-
5) with the pyrazolate-N2 in the apical position. The
degree of trigonality can be evaluated by means of the
angular structural parameter ~=(i−h)/60 introduced
by Addison et al. [17], where h and i represent the two
largest angles around the central atom with i\h (a
perfect TB-5 structure is associated with ~=1, while
~=0 is expected for ideal SPY-5 geometry). ~ values in
the range 0.93–0.99 are generally observed for the
[tmpaZnCl]+ system [15]. In contrast, ~=0.57 is calcu-
lated for Zn1 in 4, confirming a coordination geometry
intermediate between TB-5 and SPY-5, which is accom-
panied by comparatively long ZnꢀCl1 and ZnꢀN3
Fig. 2. View of the molecular structure of 4. In the interests of clarity
,
all hydrogen atoms have been omitted. Selected atom distances (A)
and angles (°): N1ꢀN2, 1.368(3); O10ꢀC10, 1.170(3); O11ꢀC11,
1.165(3); Zn1ꢀN2, 2.001(2); Zn1ꢀN3, 2.297(2); Zn1ꢀN4, 2.109(2);
Zn1ꢀN5, 2.172(2); Zn1ꢀCl1, 2.289(2); Mn1ꢀN1, 2.018(2); Mn1ꢀC5,
2.147(2); Mn1ꢀC6, 2.146(2); Mn1ꢀC7, 2.128(3); Mn1ꢀC8, 2.124(3);
Mn1ꢀC9, 2.151(3); Mn1ꢀC10, 1.766(3); Mn1ꢀC11, 1.772(2);
Mn1···Zn1, 4.152; N2ꢀZn1ꢀN3, 78.88(8); N2ꢀZn1ꢀN4, 109.87(8);
N2ꢀZn1ꢀN5, 110.66(8); N2ꢀZn1ꢀCl1, 123.19(6); N3ꢀZn1ꢀCl1,
157.31(6);
N4ꢀZn1ꢀCl1,
98.43(6);
N5ꢀZn1ꢀCl1,
92.22(6);
,
,
bonds (d (ZnꢀCl)=2.289(1) A in 4 vs. 2.271–2.275 A
C10ꢀMn1ꢀC11, 93.1(2); C10ꢀMn1ꢀN1, 100.3(2); C11ꢀMn1ꢀN1,
98.32(9).
+
,
in [tmpaZnCl] ; d (ZnꢀN3)=2.297(2) A vs. 2.228–

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J.C. Ro¨der et al. / Journal of Organometallic Chemistry 641 (2002) 113–120
(Fig. 3) [19], which we assign to the formation of the
MnII (d5) species. No further redox processes are de-
tectable in the potential range −1.6 to +1.6 V. Oxida-
tion potentials of CpMn(CO)2L complexes are known
to vary over a potential range of more than 2 V,
depending of the nature of the ligand L [20–23]. The
rather low oxidation potential of 4 indicates significant
stabilization of the MnII state by the anionic pyrazolate
ligand and reflects the high nucleophilicity of the N-het-
erocycle [22].
Fig. 3. Cyclic voltammogram of 4 in CH2Cl2. Potentials are given in
To characterize the oxidized MnII species 4+, the
oxidation of 4 in dichloroethane was followed by IR-
and UV–vis spectroscopy in an OTTLE cell (Figs. 4
and 5). Upon gradual electrolysis of 4, the pair of CO
stretching vibrations at 1835 and 1910 cm−1 decrease
at the expense of two new bands at 1964 and 2041
cm−1, thus confirming structural integrity of the
CpMn(CO)2 fragment upon generation of 4+. The
lower intensity of the new bands is as expected, since in
MꢀCO moieties spectral intensities usually decrease
with increasing oxidation state [24]. Likewise, the shift
to higher frequencies of ꢀ130 cm−1 is in accordance
with a Mn-centered oxidation and reflects the dimin-
ished backbonding ability of the oxidized MnII. Upon
re-reduction, the original spectrum of the starting mate-
rial 4 is almost restored. In UV–vis spectroelectro-
chemistry, the oxidation of 4 is accompanied by an
increase in absorptivity (Fig. 5) due to the rise of a new
band at 400 nm, which we assign to the
p(pyrazolate)“MnII LMCT transition.
volts versus the saturated calomel electrode (SCE).
Fig. 4. IR spectroscopic changes during gradual oxidation of 4 in an
OTTLE cell. The asterisks mark an impurity (presumably the
Mn(CO)3 precursor of 4).
The CpMn(CO)2 moiety itself is known to be kineti-
cally very stable [20,23] and has been extensively used
for the formation of various CpMn(CO)2L complexes
[22,25,26]. These CpMn(CO)2L compounds, on the
other hand, exhibit notorious kinetic lability, in particu-
lar in their oxidized MnII form. In 4 and 4+, however,
the rigid chelate arrangement is anticipated to preclude
dissociation of the organometallic fragment from the
bridging pyrazolate. In addition, the p plane of the
heterocycle roughly coincides with the mirror plane of
the Mn(CO)2 moiety, which is a very favourable struc-
tural situation for Mn-pyrazolate p-interactions and
consequently for electronic communication between the
Mn site and the second metal ion. These particular
features of the present type of bimetallic complexes —
in combination with the possibility of accommodating
various different metal ions in the N4 pocket and the
obvious ease of oxidation of the organometallic part of
the bimetallic system — suggests to use the
CpMn(CO)2 subunit as an electron reservoir for redox
reactions occurring at the adjacent Werner-type site, i.e.
for so-called one-site addition two-metal oxidation pro-
cesses [27].
Fig. 5. UV–vis spectroscopic changes during gradual oxidation of 4
in an OTTLE cell.
,
2.271 A) [15]. We consider steric hindrance between the
Cl atom and the Mn-bound CO ligands within the
bimetallic pocket as the likely reason for this geometric
distortion: determined by the rigid bimetallic scaffold,
rather short Cl···CO distances are enforced in 4 [d
,
(Cl1···C10/O10)=3.56/3.54 A], preventing a more lin-
ear N3ꢀZn1ꢀCl1 arrangement. Also imposed by the
rigid chelating ligand framework, the NꢀMnꢀCO bond
angles are somewhat widened [98.32(9) and 100.3(2)°].
A
CSD search [18] revealed that complexes of
CpMn(CO)2 fragments with N-donor ligands not teth-
ered to the Cp usually have NꢀMnꢀCO bond angles in
the range 92.6–98.1°.
A cyclic voltammogram of 4 in CH2Cl2 solution
features a reversible redox wave at E1/2= −0.20 V
In conclusion, we have prepared and structurally
characterized a novel bimetallic complex 4, in which a
classical Werner-type coordination subunit is located in

J.C. Ro¨der et al. / Journal of Organometallic Chemistry 641 (2002) 113–120
117
close proximity to a soft organometallic fragment in a
predefined manner. The chemistry of such preorganized
heterobimetallic systems that incorporate two very dis-
tinct sites will be explored in more detail in future
work, focusing (i) on the influence of different metal
ions in the N4 compartment on the electronic properties
of the organometallic site as well as (ii) on the use of
the CpMn(CO)2 fragment as an electron reservoir for
substrate transformations that proceed via one-site ad-
dition two-metal oxidation reactions at the Werner-type
metal site.
mmol) in THF (10 ml) by means of a 1 M solution of
DIBAH in hexane (0.20 ml, 0.20 mmol). The catalyst
solution was then transferred to the reaction mixture
via a canula, and finally a solution of 1 (1.20 g, 4.90
mmol) in THF (20 ml) was added. Stirring was contin-
ued for 1 h at −78 °C and further 72 h at room
temperature (r.t.) under Ar and under exclusion of
light. After hydrolyzing by the addition of aqueous
NaCl, the organic phase was separated, dried over
MgSO4 and the solvent removed under reduced pres-
sure. The product 2 was purified by column chromatog-
raphy (silica gel, CH2Cl2–light petroleum 1:1, Rf
(Et2O–light petroleum 1:1)=0.55). Colorless crys-
talline material could be obtained by slow diffusion of
light petroleum into a solution of the product in a small
amount of CH2Cl2. Yield: 1.53 g, 3.60 mmol, 74%.
1H-NMR (CDCl3): l=1.65–1.69 (br, m, 3H,
CHt2hp, 4/5), 1.94–2.12 (br, m, 2H, CHt2hp, 3/4), 2.33 (br,
m, 1H, CHt2hp, 3), 3.66 (br, m, 3H, CH2Cp and CHt2hp, 6),
4.04 (d, 3J=10.1 Hz, 1H, CHt2hp, 6), 4.55 (s, 2H,
3. Experimental
3.1. General procedures and methods
All manipulations were carried out under an atmo-
sphere of dry Ar by employing standard Schlenk tech-
niques or else in a glove box. Solvents were dried
according to established procedures. Compound 1 was
synthesized according to the reported method [5], all
other chemicals were used as purchased. Microanalyses:
Mikroanalytische Laboratorien des Organisch-Chemis-
chen Instituts der Universita¨t Heidelberg. IR spectra:
Perkin–Elmer 983G; recorded as KBr pellets. Cyclic
voltammetry: PAR equipment, (potentiostat/galvanos-
tat 273), in 0.1 M NBu4PF6ꢀCH2Cl2. Potentials in V on
glassy carbon electrode, referenced to SCE at ambient
temperature. UV–vis spectra: Perkin–Elmer Lambda
19. FAB-MS spectra: Finnigan MAT 8230. HR-MS
spectra: JEOL JMS700. NMR spectra: Bruker AC 200
at 200.13 (1H) and 50.32 (13C) MHz, or Bruker DRX
300 at 300.13 MHz (1H) and 75.47 (13C) MHz, or
Bruker DRX 500 at 500.13 MHz (1H) and 125.77 (13C)
MHz; residual proton signal of the solvent as internal
chemical shift reference. Spectroelectrochemistry: Self-
constructed OTTLE cell comprising a Pt-mesh working
and counter electrode and a silver wire as pseudo-refer-
ence electrode sandwiched in between the CaF2 win-
dows of a conventional liquid IR cell. The working
electrode is positioned in the center of the spectrometer
beam with all other parts of the cell made non-trans-
parent to the incident beam by means of an absorbing
tape [28].
CH2Cl), 4.70 (d, J=2 Hz, 2H, CHCp), 4.73 (d, J=2
Hz, 2H, CHCp), 5.26 (dd, 3J=9.7 Hz/2.5 Hz, 1H,
CHt2hp, 2), 6.11 (s, 1H, CHpz, 4). 13C-NMR (CDCl3):
l=22.3 (CHt2hp, 4), 24.3, 24.5 (CH2thp, 5, CH2Cp), 29.2
(CHt2hp, 3), 38.8 (CH2Cl), 67.4 (CHt2hp, 6), 81.5, 81.8
(CHCp), 83.1 (CHthp, 2), 101.7 (CCp), 105.6 (CHpz, 4),
143.0 (Cpz, 5), 148.8 (Cpz, 3), 224.7 (CO). IR (KBr): 2956
w, 2859 w, 2023 vs, 1921 vs, 1541 w, 1454 m, 1366 w,
1252 m, 1202 w, 1124 w, 1081 m, 1075 w, 1039 s, 1002
m, 920 w, 883 w, 795 w, 732 w, 666 m, 634 s, 536 w.
MS (EI); m/z (%): 416 (20) [M+], 332 (100) [M+−
DHP]. Calc. for C18H18ClMnN2O4 (416.73): C 51.87, H
4.35, N 6.72, Cl 8.51. Anal. Found: C 51.82, H 4.42, N
6.76, Cl 8.77%.
3
3
3.3. Compound 3thp
Na2CO3 (4 g, 37 mmol) was dried at 100 °C under
vacuum for 1 h. After cooling to r.t., a solution of 1
(1.53 g, 3.60 mmol) and di(2-picolyl)amine (0.79 g, 3.96
mmol) in MeCN (50 ml) were added. The suspension
was stirred overnight at 75 °C under exclusion of light,
then filtered and the residue washed several times with
small portions of MeCN. Evaporation of the combined
organic phases yielded a red–brown oil that was
purified by Kugelrohr destillation under vacuum to
1
yield 3 (1.54 g, 2.66 mmol, 73%). H-NMR (CDCl3):
l=1.61–1.66 (br, m, 3H, CHt2hp,4/5), 1.90–2.10 (br, m,
2H, CH2thp,3/4), 2.43 (br, m, 1H, CHt2hp,3), 3.57 (br, m,
1H, CHt2hp,6), 3.65 (s, 2H, CH2Cp), 3.71 (s, 2H, CH2N),
3.82 (s, 4H, NCH2Py), 4.00 (d, 3J=10.6 Hz, 1H,
3.2. Compound 2
CpMn(CO)3 (2.00 g, 9.80 mmol) was dissolved in
THF (50 ml) and a 2.5 M solution of n-BuLi in hexane
(3.90 ml, 9.80 mmol) added via a syringe at −78 °C.
After stirring for 1 h at low temperature, ZnCl2 (1.30 g,
9.80 mmol) in THF (20 ml) was added and stirring
continued for further 1 h. In a separate flask, a solution
of the Pd(0) catalyst [Pd(PPh3)2] was prepared by re-
duction of a suspension of [PdCl2(PPh3)2] (0.07 g, 0.10
3
CH2thp,6), 4.66–4.71 (br, m, 4H, CHCp), 5.22 (d, J=8.2
Hz, 1H, CHt2hp,2), 6.14 (s, 1H, CHpz,4), 7.11 (pseudo-t,
3J=6.5 Hz, 2H, CHpy,5), 7.54–7.65 (br, m, 4H, CHpy,3/
4), 8.49 (d, 3J=6.5 Hz, 2H, CHpy,6). 13C-NMR
(CDCl3): l=22.3 (CHt2hp,4), 24.2, 24.6 (CH2thp,5
,
CH2Cp), 29.3 (CH2thp,3), 51.3 (CH2N), 59.5 (NCH2Py),

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J.C. Ro¨der et al. / Journal of Organometallic Chemistry 641 (2002) 113–120
67.3 (CHt2hp,6), 81.4, 81.7, 83.0, 83.1 (CHCp), 84.3
(CHthp,2), 102.0 (CCp), 106.1 (CHpz,4), 121.5 (CHpy,5),
122.6 (CHpy,3), 136.0 (CHpy,4), 141.2 (Cpz,5), 148.7
(CHpy,6), 149.2 (Cpz,3), 159.5 (Cpy,2), 224.5 (CO). IR
(film): 3379 w, 3058 w, 3000 w, 2931 s, 2843 m, 2014 vs,
1922 vs, 1585 s, 1563 m, 1549 w, 1467 s, 1428 s, 1396 w,
1358 w, 1313 w, 1258 m, 1203 m, 1128 m, 1080 s, 1040
s, 1003 m, 916 w, 882 w, 845 w, 811 w, 759 s, 667 s, 635
s. MS (EI); m/z (%): 579 (2) [M+], 403 (70) [M+−
C6H6N−3CO], 319 (35) [M+−C6H6N−3CO−
DHP]. Calc. for C30H30MnN5O4 (579.52): C 62.17, H
5.21, N 12.08. Anal. Found: C 62.33, H 5.27, N
12.30%.
petroleum, then dissolved in CH2Cl2 and the crude
product 4 precipitated by the addition of Et2O (0.24 g,
0.43 mmol, 82%). Single crystals were obtained from a
1
concentrated CH2Cl2 solution. H-NMR (CD2Cl2): l=
3.68 (s, 2H, CH2Cp), 3.79 (s, 2H, CH2N), 4.00 (m, 4H,
NCH2Py), 5.16 (s, 4H, CHCp), 5.66 (s, 1H, CHpz,4), 7.35
(br, s, 2H, CHpy,5), 7.54 (br, s, 2H, CHpy,3), 7.92 (br, s,
2H, CHpy,4), 9.47 (br, s, 2H, CHpy,6). 13C-NMR
(CD2Cl2): l=27.3 (CH2Cp), 44.3 (CH2N), 56.8
(NCH2Py), 77.5 (CHCp), 98.0 (CHpz,4), (CCp) not ob-
served, 123.7 (CHpy,5), 124.9 (CHpy,3), 140.3 (CHpy,4),
151.4, 154.9 (CHpy,6), (Cpz,5), (Cpz,3), (Cpy,2), (CO) not
observed. IR (KBr): 3437 s, 2921 m, 1897 vs, 1820 vs,
1601 m, 1478 m 1432 m, 1382 w, 1336 w, 1259 m, 1100
w, 1051 w, 1016 w, 772 m, 659 w, 644 w, 634 w, 610 w,
583 w, 476 w, 415 w. MS (FAB); m/z (%): 567 (15)
3.4. Compound 3
A solution of 3thp (1.54 g, 2.66 mmol) in EtOH (20
ml) was treated with ethanolic HCl (10 ml) and stirred
overnight under exclusion of light. Addition of Et2O
(100 ml) caused precipitation of the hydrochloride salt
of 3 as a brownish solid. This was separated by filtra-
tion, neutralized with aqueous Na2CO3 and extracted
with several portions of CH2Cl2. After drying the com-
bined organic phases over MgSO4, the solvent was
evaporated to give the crude product as a red–brown
oil that was purified by Kugelrohr distillation under
vacuum. Yield: 1.31 g (2.26 mmol), 84%. 1H-NMR
(CDCl3): l=3.63 (s, 2H, CH2Cp), 3.73 (s, 2H, CH2N),
3.80 (s, 4H, NCH2Py), 4.64 (s, 2H, CHCp), 4.76 (s, 2H,
Table 2
Crystal data and refinement details for 2 and 4·CH2Cl2
2
4
Empirical
formula
Formula weight 416.73
Crystal size
(mm)
Crystal system
Space group
C18H18ClMnN2O4
C
24H21ClMnN5O2Zn·
CH2Cl2
652.14
0.25×0.25×0.08
0.50×0.15×0.15
Orthorhombic
Pbca
Triclinic
P1
(
Unit cell dimensions
3
CHCp) 6.02 (s, 1H, CHpz,4), 7.19 (pseudo-t, J=6.5 Hz,
,
a (A)
20.046(4)
8.532(17)
21.548(4)
90
90
90
3685.4(13)
1.502
8
1712
200
8.270(17)
9.439(19)
17.472(4)
93.34(3)
93.39(3)
98.79(3)
1342.4(5)
1.613
2
660
200
0.071
,
b (A)
2H, CHpy,5), 7.38 (d, 3J=6.5 Hz, 2H, CHpy,3), 7.65
,
c (A)
3
3
(pseudo-t, J=6.5 Hz, 2H, CHpy,4), 8.58 (d, J=6.5
Hz, 2H, CHpy,6). 13C-NMR (CDCl3): l=27.1
(CH2Cp), 47.4 (CH2N), 59.1 (NCH2Py), 81.4, 83.0
(CHCp), 103.5 (CHpz,4), 104.3 (CCp), 122.1 (CHpy,5),
123.5 (CHpy,3), 136.5 (CHpy,4), 140.3 (Cpz,5), 148.8
(CHpy,6), 150.2 (Cpz,3), 158.2 (Cpy,2), 224.9 (CO). IR
(film): 3177 s, 3093 s, 3007 s, 2919 s, 2880 s, 2831 s,
2013 vs, 1917 vs, 1587 s, 1565 s, 1469 s, 1429 s, 1359 m,
1307 w, 1244 w, 1146 m, 1120 w, 1089 w, 1046 w, 1026
w, 993 m, 836 m, 762 s, 668 s, 634 s. MS (FAB neg);
m/z (%): 494 (100) [M−−H]. Calc. for C25H22MnN5O3
(495.41): C 60.61, H 4.47, N 14.13. Anal. Found: C
60.80, H 4.54, N 14.20%.
h (°)
i (°)
k (°)
3
,
V (A )
Dcalc (g cm−3
Z
)
F(000)
T (K)
v (Mo–Ka)
0.071
(mm−1
)
Index range
−265h5+25,
−105k5+10,
−275l5+27
3.8–55.0
−105h5+10,
−125k5+12,
−215l5+22
4.4–55.0
2q Range (°)
Measured
reflections
Unique
reflections
Observed
reflections
[I\2|(I)]
Refined
8123
8517
4172
3079
5789
4771
3.5. Compound 4
A solution of 3 (0.26 g, 0.52 mmol) in THF (200 ml)
was irradiated with a high pressure mercury lamp in a
quartz schlenk tube at −40 °C for 15 min. During this
time, the solution became darker while the reaction was
followed by IR spectroscopy. After warming to r.t.,
ZnCl2 (0.71 g, 0.52 mmol) and KOtBu (0.58 g, 0.52
mmol) were added and the reaction mixture stirred
overnight. After removal of the solvent under reduced
pressure, the pale yellow residue was washed with light
307
337
parameters
Residual electron 0.408/−0.587
0.531/−0.758
density
−3
,
(e A
R1
)
0.043
0.112
1.037
0.034
0.080
1.026
wR2 (all data)
Goodness-of-fit

J.C. Ro¨der et al. / Journal of Organometallic Chemistry 641 (2002) 113–120
119
[M+], 511 (100) [M+−2CO]; HRMS (FAB); m/z (%):
(c) O. Segnitz, M. Winter, K. Merz, R.A. Fischer, Eur. J. Inorg.
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37
[Err/mmu]=567.0081 (10.7) [+5.4 calc. for C24H21
21
-
ClMnN5O624Zn], [+5.6 calc. for C24H ClMnN5-
35
O626Zn].
Calc.
for
C24H21ClMnN5O2Zn·CH2Cl2
(652.16): C 46.04, H 3.55, N 10.73. Anal. Found: C
46.84, H 3.87, N 11.68%. C and N values are somewhat
higher than calculated due to partial loss of CH2Cl2.
3.6. X-ray crystallography of 2 and 4
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The measurements were carried out on a Nonius
Kappa CCD diffractometer using graphite-monochro-
mated Mo–Ka radiation. All calculations were per-
formed using the SHELXT PLUS software package.
Structures were solved by direct methods with the
SHELXS-97 and refined with the SHELXL-97 program
[29]. Atomic coordinates and thermal parameters of the
non-hydrogen atoms were refined in anisotropic models
by full-matrix least-squares calculation based on F2. In
general the hydrogen atoms were placed at calculated
positions and allowed to ride on the atoms they are
attached to. Table 2 compiles the data for the structure
determinations.
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Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 162375 and 163317 for com-
pounds 2 and 4, respectively. Copies of this information
may be obtained free of charge from The Director,
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
(Fax: +44-1223-336033; e-mail: deposit@ccdc.cam.
ac.uk or www: http://www.ccdc.cam.ac.uk).
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Acknowledgements
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(b) F. Meyer, E. Kaifer, P. Kircher, K. Heinze, H. Pritzkow,
Chem. Eur. J. 5 (1999) 1617;
Prof. Dr G. Huttner is sincerely thanked for his
continuous generosity and his interest in our work.
Financial support by the Deutsche Forschungsgemein-
schaft (SFB 247, Heisenbergstipendium for F.M.,
Graduiertenkollegs-Stipendium for J.C.R.) and the
Fonds der Chemischen Industrie is gratefully
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