Synthetic, spectroscopic, and structural studies on organoimido molybdenum, tungsten, and rhenium phthalocyanines

Article abstract of DOI:10.1039/c0dt01166e

Unprecedented imido phthalocyaninato complexes of pentavalent refractory metals [PcM(NR)Cl] (M = Mo, W, Re; R = tBu: 1, 3, 6, Mes: 2, 4, 7 or Ts: 5) have been synthesized by reductive cyclotetramerization of phthalonitrile in the presence of appropriate bis(imido) complexes of Mo, W and Re as templates. While d¹ Mo(v) and W(v) species 1-5 show distinctive EPR spectra corresponding to metal centered radicals with hyperfine coupling of two magnetically non-equivalent nitrogen atoms (4 equatorial and 1 axial N), corresponding d² Re(v) compounds 6 and 7 are diamagnetic. [PcMo(NtBu)Cl] 1 crystallizes from 1-chloronaphthalene in the tetragonal space group P4/n. The molecular structure reveals, that the metal center is located above the plane of the equatorial N4 and displaced towards the axial π-donor ligand. Due to the thermodynamic trans effect the Mo-Cl bond trans to the imido group is elongated to about 2.600(2) A.

Full text of DOI:10.1039/c0dt01166e

View Article Online / Journal Homepage / Table of Contents for this issue
Dynamic Article Links
Dalton
Transactions
Cite this: Dalton Trans., 2011, 40, 1183
www.rsc.org/dalton
PAPER
Synthetic, spectroscopic, and structural studies on organoimido molybdenum,
tungsten, and rhenium phthalocyanines†
Wael Darwish, Elisabeth Seikel, Klaus Harms, Olaf Burghaus and Jo¨rg Sundermeyer*
Received 3rd September 2010, Accepted 11th November 2010
DOI: 10.1039/c0dt01166e
Unprecedented imido phthalocyaninato complexes of pentavalent refractory metals [PcM(NR)Cl]
(M = Mo, W, Re; R = tBu: 1, 3, 6, Mes: 2, 4, 7 or Ts: 5) have been synthesized by reductive cyclotetra-
merization of phthalonitrile in the presence of appropriate bis(imido) complexes of Mo, W and Re as
templates. While d1 Mo(V) and W(V) species 1–5 show distinctive EPR spectra corresponding to metal
centered radicals with hyperfine coupling of two magnetically non-equivalent nitrogen atoms (4
equatorial and 1 axial N), corresponding d2 Re(V) compounds 6 and 7 are diamagnetic.
[PcMo(NtBu)Cl] 1 crystallizes from 1-chloronaphthalene in the tetragonal space group P4/n. The
molecular structure reveals, that the metal center is located above the plane of the equatorial N4 and
displaced towards the axial p-donor ligand. Due to the thermodynamic trans effect the Mo–Cl bond
˚
trans to the imido group is elongated to about 2.600(2) A.
more, Mo(IV) imido porphyrins [(TPP)Mo NR] (R = aryl) were
prepared by reaction of [(TPP)MoCl2] with 2 equiv. of LiNHR.11
Other macrocycle-supported imido complexes have been synthe-
sized starting from the preformed imido complexes. For exam-
ple, organoimido molybdenum and tungsten calix[4]arene (Cax)
compounds were prepared by treatment of p-tBu-calix[4]arene
with [M(NtBu)2(NHtBu)2], with [M(NMes)2Cl2(dme)] (M = Mo
or W)12 and [W(NPh)Cl4],13 respectively. An imido tungsten
calix[4]arene was prepared by the reaction of the disodium salt of
a calix[4]arene with [W(NTol)Cl4].14 Similarly, an imido rhenium
calix[4]arene was prepared by the reaction of Cax(OH)4 with
[Re(NtBu)2Cl3].15
Recently, we reported the synthesis and axial ligand reactivity
of soluble, highly reactive imido- and ureato-phthalocyaninato
titanium(IV) complexes.16–17 In this account, we extend these
studies to the chemistry of group 6 and 7 metals and describe
the synthesis, structural and spectroscopic properties of pure
pentavalent molybdenum, tungsten and rhenium complexes of the
type [PcM(NR)Cl] 1–7.
Introduction
As a consequence of their versatility and interesting material prop-
erties, metallo phthalocyanines have found a tremendous range of
applications in many fields of light-driven processes. Traditionally
they serve as thermostable dyes, but during the last decades
their functions as photo catalysts, optical limiting materials,
photo sensitizers, and molecular semi-conductors, among others,
were discovered and refined.1–4 The chemistry of molybdenum,
tungsten, or rhenium accommodated by the phthalocyanine
ligand (Pc2-) is so far limited to oxo, halogeno,5–7 and nitrido
complexes.8 Phthalocyanine complexes incorporating two-valent
refractory metals occur as dimers of the type [PcM–MPc] with a
molybdenum-molybdenum quadruple or rhenium-rhenium-triple
bond, respectively.7 Hanack et al. reported the reaction of nitrido
metal phthalocyanines with group 13 Lewis acids EX3 and trialkyl
silyl chloride, leading to PcM N → EX3 adducts and ionic rhe-
nium or neutral tungsten silyl imido compounds.9 Phthalocyanines
of the refractory metals containing organoimido functionalities
(PcM NR) have not been realized so far, even though imido
derivatives of Mo, W, and Re supported by other macrocyclic
ligands such as porphyrins and calix[4]arenes are known. For
example, a Mo(V) imido porphyrin salt [Mo(NMe)(TPP)(H2O)][I3]
(TPP = tetraphenylporphyrin) was prepared by the reaction of
nitrido compound [(TPP)Mo N] with methyliodide.10 Further-
Results and discussion
The organoimido functionality (M = NR; M = Mo, W or Re
and R = tBu, Mes or Ts) could be successfully accommodated
in the cavity of Pc2- ligand when the cyclotetramerization of
phthalonitrile is carried out in the presence of an appropriate
metal Lewis acid containing a preformed imido functionality. The
Lewis acid does not only act as a precursor for the M NR group
but also as initiator for the cyclotetramerization process, since four
molecules of phthalonitrile (PN) do not form phthalocyanines in
absence of urea and/or a metal precursor.1 The use of urea as
promoter had to be avoided because the presence of urea promotes
Philipps-Universita¨t Marburg, Fachbereich Chemie, Hans-Meerwein Straße,
35043, Marburg. E-mail: jsu@staff.uni-marburg.de; Fax: +49 6421
2825711; Tel: +49 6421 2825693
† Electronic supplementary information (ESI) available: CIF files for
1, mass spectra and NMR spectra. CCDC reference numbers [CCDC
NUMBER(S)]. For ESI and crystallographic data in CIF or other
electronic format see DOI: 10.1039/c0dt01166e
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 1183–1188 | 1183
©

View Article Online
the formation of the metal free PcH2 rather than the slower process
involving the reductive cyclotetramerization of four PN units at
the imido metal template. In earlier studies we found, that due to
their oxidation potential mono imido precursors [M(NR)Clx] lead
to aromatic ring-chlorination in the formed Pc’s. The discovery of
a highly selective synthetic protocol was essential, as PcH2 or ring-
chlorinated Pc’s cannot be separated from the desired products.
The m/z values of the [M - Cl]+ ions of compounds 1–5 were
obtained by MALDI-TOF and APCI-HRMS measurements and
show exactly the expected isotopic patterns. The molecular ion
peaks (M+) are much less intense, so that no high resolution spectra
could be obtained. They are so low in intensity, that one erro-
neously might assume from simple standard EI-MS experiments,
that the final products have the composition [PcM(NR)]. This
shows that the M–Cl bonds are rather weak. To definitely prove
that chloride is bound to the central metal and thereby exclude the
formation of ring-chlorinated Pc compounds, 1 was reacted with
AgSbF6 in a mixture of toluene and THF affording an intensely
green suspension and a white precipitate of AgCl. This evidences
the presence of inorganic chloride linked to the central metal atom
and not to the ring.
Imido Mo(V) and imido W(V) phthalocyanines
Melting
4 equiv. of phthalonitrile in the presence of
1 equiv. [Mo(NR)2Cl2(dme)]18,19 (R = tBu, Mes), [W(NtBu)2-
Cl2(NH2tBu)]20 or [W(NMes)2Cl2(dme)]19 afford the paramagnetic
air stable organoimido compounds [PcM(NR)Cl] 1–4 (Scheme 1).
In case of [W(NtBu)2Cl2(NH2tBu)], a low yield of 6% is obtained,
in case of [W(NtBu)2Cl2py2] no phthalocyanine was obtained.
This is in accord with a mechanism involving Lewis acid
induced cyclotetramerization. Phthalodinitrile doesn’t replace
pyridine. Unfortunately, the ideal precursor for this synthesis
[W(NtBu)2Cl2(dme)] is not known. Tosylimido phthalocyanine
[PcW(NTs)Cl] 5 was obtained by reaction of phthalonitrile with
the coordination polymer [W(NTs)2Cl2]21 under careful time and
temperature control. Hanack et al. described the reaction of
[W(NTs)2Cl2] with substituted phthalodinitriles leading to nitrido
phthalocyanines.9 We believe that the nitrido compounds are
formed by TsCl elimination during their work up with protic
solvents reported by Hanack et al. If extraction of the crude
product is solely accomplished with aprotic solvents hydrolytically
unstable [PcW(NTs)Cl] 5 and not a hydrolytically rather stable
nitrido complex is formed.
[PcM(NR)Cl] + AgSbF6 → [PcM(NR)][SbF6] + AgCl
Both APCI and MALDI-TOF spectra of compounds 1–
5 do not show the characteristic molecular ion peaks of the
analogous nitrido compounds [PcMN], consequently the thermal
degradation of the product to the nitrido species can be safely
ruled out.
UV-vis spectra of compounds 1–5 show the typical absorption
bands of the host macrocycle in the range of 710 nm. Fig. 1
shows the spectra of the tree analogous NtBu compounds 1,
3 and 6. A hypsochrome shift of the Q band absorption is
observed when going from the Mo compound (718 nm) to
W (708 nm) and Re (700 nm). The solubility of compounds
[PcM(NtBu)Cl] in 1-chloronaphthalene dramatically decreases in
the order M = Mo > W > Re. This might be an indicator for
increasing ionic character in the M–Cl bond. Associated with
decreasing solubility, additional absorptions at higher wavelength
are observed in particular for W and Re derivatives, which is
in accord with increasing trend of formation of pairs or higher
aggregates. Another explanation for bands at higher wavelengths
are metal-to-ligand or ligand-to-metal charge transfer processes.22
Scheme 1 Synthesis of compounds 1–5.
To provide a plausible mechanism for the formation of these
compounds, it is essential to take redox chemistry into account.
Two electrons are required for the reduction of four phthaloni-
trile units to the phthalocyanine dianion (Pc2-). Neither the solvent
and reactant PN nor the d0 metal template can directly provide
these electrons. In order to meet the electron balance, formal
homolytic cleavage and loss of a nitrene diradical and a chlorine
radical at the metal has to be considered during this template
reaction at 210 ◦C. This explains that ring-chlorination can occur
as one of the quenching reactions of these radicals. Having a low
concentration of chlorine radicals present, this process leads to
the selective formation of pure products [PcM(NR)Cl], in which
the metal has the oxidation state +V.
Fig. 1 UV-vis spectra of 1, 3 and 6 in 1-chloronaphthalene.
IR spectra of compounds 1–5 show the absorptions com-
mon for the spectra of the basic Pc moiety (e.g. nC
at
C arom.
1
nearly 1602 cm-1). Compared to the IR spectra of PcH2 and
[PcTi(NR)],16,23 new absorptions were observed in the spectra of
1 and 2 such as the shoulder at about 1260 cm-1, which can be
assigned to nMo
in the Mo N–C system. Additionally, IR
N
1184 | Dalton Trans., 2011, 40, 1183–1188
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
◦
˚
Table 2 Selected bond distances (A) and angles ( ) of 1
Table 1 g values of 1, 2 and selected Mo(V) compounds
g
Ref.
Mo1–N11
Mo1–N1
Mo1–Cl1
N11–C10
1.704(7)
2.054(3)
2.600(2)
1.424(15)
Cl1–Mo1–N11
Mo1–N11–C10
N1–Mo1–N1a
180
162.9(7)
88.73(3)
[PcMo(NtBu)Cl] (1)
[PcMo(NMes)Cl] (2)
[PcMoN]
[TPPMo(NMe)(H2O)][I3]
[TTPMoOCl]
1.979
1.972
1.97
1.9766
1.971
This work
This work
9
10
25
Crystal structure of [PcMo(NtBu)Cl] 1
Crystallization of 1 from non-dried 1-chloronaphthalene as ob-
tained from Acros did not lead to hydrolysis of the compound
but to formation of a crystalline hydrate. This stability against
hydrolysis is characteristic for d1 Mo organoimido complexes
rather than for d0 complexes. The molecular structure of 1 in the
solid state is shown in Fig. 3. Selected bond distances and angles
of 1 are given in Table 2.
spectra of 1 and 2 did not evidence the characteristic Mo
N
stretching band at 953 cm-1, which was present for [PcMo N].8,9
Similarly, the IR spectra of 3, 4 and 5 did not evidence the
characteristic (W N) stretching band at 959 cm-1, which was
present for [PcW N].8,9 Raman spectra of 1 and 2 both show
the skeletal vibrations in the frequency range 1300–1610 cm-1
and in the high frequency region. The spectra were obtained by
excitation at 432 nm. An important feature in the Raman spectra
of 1 and 2 is the absence of the characteristic absorption of nMo–Mo
around 310 cm-1 and consequently the formation of a d1–d1 M–M
bonded molybdenum phthalocyanine dimer can be safely ruled
out.24 Similarly, in the Raman spectra of 3 and 4, the absorption
of a W–W bond at about 275 cm-1 is absent.24
EPR spectra of imido Mo(V) and imido W(V) phthalocyanines 1–5
EPR spectra of solutions of 1–5 in toluene/1-chloronaphthalene
(3 : 1) were recorded at various temperatures and are consistent
with the expected values for d1 molybdenum compounds. The
experimental and simulated spectra of 1 are shown in Fig. 2. The
super hyperfine structure is in accordance with the simulation for
the coupling of the central metal with two kinds of non-equivalent
nitrogen atoms Nax and Neq (Fig. 2). The g values of 1.979 for
1 and 1.972 for 2, respectively, are comparable with those found
for other porphyrinoid Mo(V) compounds (Table 1). Similarly,
the experimental epr spectra of W(V) compounds 3 and 4 are in
accordance with the simulations. The giso values are 1.959 for 3,
1.914 for 4 and 1.88 5 (solid state), respectively. This supports
the suggested structure, in which the metal is surrounded by the
macrocycle occupying the four equatorial positions and the imido
and chloride ligands in the axial positions.
Fig. 3 Molecular structure of 1. Displacement ellipsoids are shown at the
50% probability level. (H atoms and disordered positions of the tert-butyl
group due to fourfold crystallographic symmetry are omitted for clarity.
Letters a, b and c indicate the following symmetry operations: a = 1/2 - y,
x, z; b = 1/2 - x, 1/2 - y, z; c = y, 1/2 - x, z.)
Seven disordered molecules of water per molecule of 1 are
observed and omitted for clarity. The molybdenum atom is
octahedrally coordinated by the four isoindoline nitrogen atoms
(Neq) forming the basal plane and two axial ligands, the imido
group and the chlorine atom. 1 exhibits fourfold crystallographic
rotational symmetry with Mo, Cl, and N11 lying on the fourfold
rotation axis. As a consequence, the tert-butyl group’s atomic
positions deviating from this axis are disordered in four crystallo-
˚
graphically imposed positions. The distances Mo–Neq = 2.054(3) A
as well as angles N1–Mo–N1b = N1a–Mo–N1c = 162.90(19)◦
are equal due to this symmetry. Both values are comparable to
those reported for porphyrin complex [Mo(NMe)(TPP)(H2O)][I3];
◦
10
˚
2.097(6) A and 162.58(25) , respectively. The four equal angles
˚
Neq–Mo–Nax of 98.55(9) A compare well with an average Neq–Mo–
Nax of 99.1◦ reported for [Mo(NMe)(TPP)(H2O)][I3]. The strong
thermodynamic trans effect of the imido ligand in combination
with steric repulsion between the tert-butyl group and the four
Neq atoms in 1 induces a displacement of the molybdenum atom
towards the imido N atom, thereby creating a shallow dome with
the four Neq atoms.10,26 The molybdenum atom lies 0.305 A above
˚
the plane defined by the four Neq atoms, which is comparable
˚
to 0.334 A in [Mo(NMe)(TPP)(H2O)][I3], but less than in pen-
5
27
˚
˚
tacoordinate [PcMoO] (0.69 A) and [(TTP)Mo S] (0.65 A).
Fig. 2 Left: the hyperfine structure of molybdenum in the EPR spectrum
of 1 (toluene/1-chloronaphthalene, 330 K). Right: the super-hyperfine
structure of molybdenum and 5 N atoms (4 Neq are equal) in 1 and the
stick diagram (220 K, modulation amplitude 1 Gpr).
˚
The Mo N distance of 1.704(7) A observed for 1 compares well
˚
with that of 1.689(6) A in [Mo(NMe)(TPP)(H2O)][I3]. The angle
C10–N11–Mo of 162.9(7)◦ in 1 deviates stronger from linearity
Dalton Trans., 2011, 40, 1183–1188 | 1185
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
than 175.34(64)◦ reported for [Mo(NMe)(TPP)(H2O)][I3]. An
angle of 160–180◦ is common for many other organoimido
imido phthalocyaninato rhenium(V) complexes [PcRe(NR)Cl]
(R = tBu 6 or Mes 7) (Scheme 2).
˚
complexes. The Mo–Cl distance of 2.600(2) A observed for 1 is
˚
elongated compared to those of 2.347(4) and 2.276(4) A reported
for [(TTP)MoCl2].28 This distance suggests a weak interaction
and a higher ionic character of the M–Cl bond compared to
porphyrinoid complexes without axial p-donor ligands.
Molecular packing of 1
Fig. 4 shows the molecular packing of [PcMo(NtBu)Cl] 1 in
the unit cell. The presence of two axial substituents (Cl and NtBu)
results in a reduction of the degree of p-stacking compared to four
and five-coordinate metallo Pc’s.
Scheme 2 Synthesis of compounds 6 and 7.
1H-NMR spectra of 6 and 7 could be obtained in C6D5Br at
100 ◦C, although the intensity of the signals is poor due to the
solubility. The spectra of 6 and 7 show two multiplets in the
aromatic region, the first multiplet in the region 9.7 ppm for the
eight protons in the 1,4-positions and the second multiplet in the
region 8.3 ppm for the eight protons in the 2,3-positions. As a
result of the well known ring current effect in phthalocyanines,30,31
the aliphatic protons show a drastic upfield-shift (tert-butyl group
in 6 at -1.52 ppm and methyl groups in 7 at -0.51 and 1.12 ppm).
Similarly, the aromatic protons of the axial ligand of 7 exhibit
an expected upfield shift as they are found in the region of
5.66 ppm. No single crystals of 6 and 7 suitable for X-ray
crystallography could be obtained, but an analogous structure
to 1 can be tentatively assumed. The m/z values for the [M+
-
Fig. 4 View of the molecular packing of 1 along the Pc planes. H atoms,
disorder of the NtBu group and solvent molecules are omitted for clarity.
Cl] ions of the prepared complexes [PcRe(NR)Cl] 6 and 7 were
obtained with the expected isotopic patterns in both APCI
and MALDI-TOF measurements. The low values of %C in the
elemental analyses obtained for 6 and 7 are attributed to the
formation of the thermally extremely stable rhenium carbides at
elevated temperatures. Chlorine analysis confirms the monochloro
rhenium complex. UV-vis spectra of both 6 (Fig. 1) and 7 in
chloronaphthalene display the common Q-band maxima in the
expected region.8,9 Compared to the IR spectra of [PcRnReO]8 and
[PcRnReN] (R = alkyl),8,9 the medium-strong band at 1288 cm-1
observed in IR spectra of 6 and 7 can be assigned to the Re N–C
stretching. The IR spectra of 6 and 7 do not show the characteristic
Re N stretching band at 953 cm-1 present in [PcRe N].8,32
Due to the molecular shape the crystal does not contain close
packed face-to-face dimers, which is commonly observed for metal
phthalocyanines containing only one axial ligand (e.g. [PcMoO],5
[PcTi(NDip)]16). A layered structure of essentially co-planar Pc-
rings is observed. Regarding the planes defined by the Neq atoms,
˚
˚
alternating short (d = 4.031 A) and long (6.062 A) interlayer
distances are observed, reflecting the different steric demand of the
layer separating chlorine atoms and water molecules vs. the bulkier
tert-butyl imido groups, respectively. Therefore, the molecules are
much less densely packed in crystalline 1 compared to [PcMoO]
and [PcTi(NDip)]. The interaction between the macrocycles’ p-
systems is greatly reduced, which enhances the solubility in rather
polar organic solvents such as chloronaphthalene and THF. A
comparison of selected distances is given in Table 3.
Conclusions
In an extension of our previous work on the synthesis of
imido titanium phthalocyanines, we herein reported a convenient
synthetic protocol for the first organoimido metal phthalocyanines
of group 6 and 7 [PcM(NR)Cl] (M = Mo, W, Re). Loss of an imido
group [NR]2- as nitrene [NR] diradical at an imido metal template
seems to be the key to a more general strategy towards the synthesis
of interesting axially functionalized metallo phthalocyanines. The
result of this multi-step reaction in molten phthalodinitrile is the
formal substitution of [NR]2- by [Pc]2-.
Imido Re(V) phthalocyanines
Fusion of phthalonitrile in the presence of [Re(NtBu)2Cl3]29 or
[Re(NMes)2Cl3py]29 (210 ◦C, 20 min) affords the diamagnetic
˚
Table 3 Selected intermolecular distances (A) in [PcMX] (interlayer
distance = shortest distance between neighbouring Neq planes)
1
[PcMoO] [PcTi(NDip)]
Shortest distance M–M 10.815 (sep. by Cl)
7.3587
3.5186
4.7709
3.4084
Experimental
11.187 (sep. by NtBu)
4.031 (sep. by Cl)
Interlayer distance
All experiments and manipulations were carried out under dry
nitrogen or argon atmosphere using standard Schlenk or glove-box
6.062 (sep. by NtBu)
1186 | Dalton Trans., 2011, 40, 1183–1188
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
techniques. Solvents—if not stated otherwise—were rigorously
purified with appropriate drying agents, distilled and stored
over molecular sieves under nitrogen. Chloronaphthalene was
purchased from Acros as a mixture of 90% of 1-chloronaphthalene
and 10% of 2-chloronaphthalene. Phthalonitrile was sublimed
under reduced pressure prior to use. The electronic spectra were
recorded on a Shimadzu UV-1601 PC-spectrophotometer. IR
spectra were recorded on a Bruker IFS 588 spectrometer. APCI
mass spectra were taken on a Finnigan LTQ-FT Spectrometer
using methanol as solvent. MALDI–TOF mass spectra were taken
on a Bruker Biflex III using pyrene as matrix. Elemental analysis
of C, H and N elements was carried out using an Elementar, Vario
EL. 1H-NMR spectra of the phthalocyanines were recorded on a
Bruker AMX 500.
[PcW(NtBu)Cl] 3. 400 mg phthalonitrile (3.13 mmol) and
367 mg [W(NtBu)2Cl2(NH2tBu)] (0.78 mmol). Yield: 35 mg, (6%).
Anal. calcd for C36H25ClN9W: C 53.85, H 3.14, N 15.70, Cl 4.41.
Found: C 51.33, H 4.01, N 15.40, Cl 5.15. UV-vis lmax/nm (1-
chloronaphthalene): 746 (sh), 708 (s), 348 (s). IR nmax(KBr)/cm-1:
2994 (s, n(CHaliph.)), 1604 (w), 1467 (m), 1408 (w), 1332 (s), 1286
(m), 1162 (w), 1115 (s), 966 (s), 956 (w), 891 (m), 853 (w), 773 (m),
750 (m), 724 (s), 571 (w). EPR (1-chloronaphthalene/toluene 1 : 3,
293 K): giso = 1.959. MALDI-TOF-MS (m/z) 802.4 [M+], 767.4
[M+ - Cl]. APCI-HRMS (m/z) 767.1750 [M+ - Cl], C36H25N9W
requires 767.1737.
[PcW(NMes)Cl] 4. 520 mg phthalonitrile (4.06 mmol) and
577 mg [W(NMes)2Cl2(dme)] (0.94 mmol). Yield: 580 mg (71%).
Anal. calcd for C41H27ClN9W: C 56.93, H 3.14, N 14.57,
Cl 4.1. Found: C 56.17, H 3.15, N 13.90, Cl 5.01. UV-vis
[Mo(NtBu)2Cl2(dme)]18 [Mo(NMes)2Cl2(dme)],19 [W(NtBu)2-
Cl2(H2NtBu)],20 [W(NMes)2Cl2(dme)],19 [W(NTs)2Cl2],21 [Re(Nt-
Bu)2Cl3]29 and [Re(NMes)2Cl3py]29 were prepared according to
literature procedures.
l
max/nm (1-chloronaphthalene): 870.0 (m), 731.0 (s), 664.0 (m).
IR nmax(KBr)/cm-1: 1605 (w), 1468 (m), 1404 (w), 1329 (s), 1284
(m), 1161 (w), 1117 (s), 966 (s), 951 (w), 893 (m), 853 (w), 773 (m),
749 (m), 724 (s), 571 (w). EPR (1-chloronaphthalene/toluene 1 : 3,
130 K): g1 = 1.927, g2 = 1.908, g3 = 1.911. MALDI-TOF-MS (m/z)
864.4 [M+], 829.4 [M+ - Cl]. APCI-HRMS (m/z) 829.1902 [M+ -
Cl], C41H27N9W requires 829.1983.
General Procedure for the Preparation of 1–7
A
mixture of 4.4 equiv. phthalonitrile and 1 equiv. of
the respective bis(imido) precursor (1: [Mo(NtBu)2Cl2(dme)],
2: [Mo(NMes)2Cl2(dme)], 3: [W(NtBu)2Cl2(NH2NtBu)], 4:
[W(NMes)2Cl2(dme)], 5: [W(NTs)2Cl2], 6: [Re(NtBu)2Cl3], 7:
[Re(NMes)2Cl3py]) was finely ground in a mortar under nitrogen
until a homogeneous powder was obtained. The mixture was
quickly heated at melt at 210 ◦C for 20 min by using a preheated
metal bath of Wood alloy. The produced dark-green solid was
suspended in 50 mL of toluene and the suspension was treated
with ultrasound at 70 ◦C for 2 h. The precipitate was collected on
a glass frit and purified by successive extractions with refluxing
toluene (10 ¥ 50 mL), MeCN (10 ¥ 50 mL) and finally washed
with pentane. The black-green solid was dried at 140 ◦C and 10-5
mbar for 5 h.
[PcW(NTs)Cl] 5. 200 mg phthalonitrile (1.56 mmol) and
136 mg [W(NTs)2Cl2] (0.35 mmol). Yield: 137 mg (45%). Anal.
calcd for C39H23ClN9O2SW: C 51.99, H 2.57, N 13.99. Found: C
51.26, H 2.91, N 13.33. UV-vis lmax/nm (1-chloronaphthalene):
762 (s), 385 (s). IR nmax(KBr)/cm-1: 2915 (w), 1619 (m), 1601 (w),
1519 (w), 1464 (s), 1326 (s), 1287 (s), 1154 (m), 1117 (m), 1057 (s),
892 (w), 768 (m), 725 (s), 552 (m). EPR (solid state, 8 K): g1 = 1.88.
APCI-HRMS (m/z) 865.1207 [M+ - Cl], C39H23N9O2SW requires
865.1203.
[PcRe(NtBu)Cl] 6. 400 mg phthalonitrile (3.12 mmol) and
308 mg [Re(NtBu)2Cl3] (0.71 mmol). Yield: 260 mg (42%). Anal.
calcd for C36H25N9ClRe: C 53.69, H 3.13, N 15.65, Cl 4.4. Found:
C 51.84, H 2.70, N 17.25, Cl 4.7. (Despite the diligent purification
of the product and multiple attempts, no better elemental analysis
could be obtained). UV-vis lmax/nm (1-chloronaphthalene): 820
(sh), 700 (s), 341.0 (w), 323.0 (s). IR nmax(KBr)/cm-1: 2969 (w),
1771 (w), 1717 (w), 1652 (w), 1609 (w), 1558 (w), 1522 (w), 1473
(s), 1409 (w), 1361 (w), 1334 (s), 1287 (m), 1260 (Re N–C), 1184
(w), 1167 (w), 1119 (m), 1101 (m), 1064 (w), 902 (w), 776 (w), 755
(w), 732 (s). 1H-NMR (500 MHz, C6D5Br, 373 K) d (ppm): -1.55
(s, 9 H, CMe3), 8.34–8.47 (m, 8 H, 2,3-Pc), 9.81–9.86 (m, 8 H, 1,4-
Pc). APCI-MS (m/z) 804 [M+], 769 [M+ - C1], MALDI-TOF-MS
(m/z) 805.5 [M+], 770.3 [M+ - Cl].
[PcMo(NtBu)Cl] 1. 282 mg phthalonitrile (22 mmol) and
200 mg [Mo(NtBu)2Cl2(dme)] (5 mmol). Yield: 220 mg (67%).
Anal. calcd for C36H25ClMoN9: C 60.47, H 3.52, N 17.63. Found:
C 59.61, H 4.33, N 17.12. UV-vis lmax/nm (1-chloronaphthalene):
718 (s), 648 (sh), 358 (s). nmax(KBr)/cm-1: 1602 (m), 1463 (m),
1328 (s), 1284 (w), 1265 (m) 1161 (w), 1115 (s), 1063 (m), 973
(w), 893 (m), 802 (w), 772 (w), 750 (m), 728 (s), 570 (w). EPR
(1-chloronaphthalene/toluene 1 : 3, 130 K): g1 = 1.989, g2 = 1.987,
g3 = 1.977. MALDI-TOF-MS (m/z) 716.2 [M+], 681.3 [M+ - Cl],
APCI-HRMS (m/z) 681.1289 [M+ - Cl], C36H25N9Mo requires
681.1282.
[PcMo(NMes)Cl] 2. 282 mg phthalonitrile (22 mmol) and
262 mg [Mo(NMes)2Cl2(dme)] (5 mmol). Yield: 280 mg (72%).
Anal. calcd for C36H25ClMoN9: C 63.36, H 3.50, N 16.22, Cl 4.6.
Found: C 63.84, H 3.76, N 14.55, Cl 5.8. UV-vis lmax/nm (1-
chloronaphthalene): 732 (s), 668 (sh), 364 (s). IR nmax(KBr)/cm-1:
1602 (m), 1462 (m), 1327 (s), 1286 (w), 1260(Mo N–C), 1161 (w),
1114 (s), 1063 (w), 972 (m), 891 (m), 802 (w), 772 (w), 749 (m),
727 (s), 569 (w). EPR (1-chloronaphthalene/toluene 1 : 3, 130 K):
g1 = 1.986, g2 = 1.981, g3 = 1.974. MALDI-TOF-MS (m/z) 778
[M+], 743 [M+ - Cl]. APCI-HRMS (m/z) 743.1439 [M+ - Cl],
C41H27N9Mo requires 743.1438.
[PcRe(NMes)Cl] 7. 898 mg phthalonitrile (7.02 mmol) and
1.02 g [Re(NMes)2Cl3py] (1.60 mmol). Yield: 1.15 g, (83%). Anal.
calcd for C41H27N9ClRe C 56.77, H 3.14, N 14.53, Cl 4.08. Found:
C 52.17, H 2.39, N 15.24, Cl 3.80 (Despite the diligent purification
of the product and multiple attempts, no better elemental analysis
could be obtained). UV-vis lmax(1-chloronaphthalene)/nm 736 (s),
664 (sh), 364 (s), 321.4 (s); IR nmax(KBr)/cm-1 1607 (w), 1474 (m),
1410 (w), 1331 (s), 1287 (w), 1261 (Re N–C) 1167 (m), 1119 (m),
1100 (w), 1063 (w), 901 (m), 872 (w), 807 (w), 775 (m), 754 (m),
727 (s); 1H-NMR (500 MHz, C6D5Br, 373 K) d (ppm) -0.51 (s, 6
H, oMe), 1.12 (s, 3 H, pMe), 5.56 (s, 2 H, Mes), 8.26–8.45 (m, 8 H,
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 1183–1188 | 1187
©

View Article Online
Table 4 X-Ray data collection parameters of 1
5 V. Bo¨rschel and J. Stra¨hle, Z. Naturforsch., 1984, 39b, 1664–1667.
6 T. Nykong, Polyhedron, 1994, 13, 215–220.
7 (a) M. Go¨ldner, L. Galich, U. Cornelissen and H. Homborg, Z. Anorg.
Allg. Chem., 2000, 626, 985–995; (b) M. Go¨ldner, A. Kienast and H.
Homborg, Z. Anorg. Allg. Chem., 1998, 624, 141–146; (c) M. Go¨ldner,
H. Hu¨cksta¨dt, K. S. Murray, B. Moubaraki and H. Homborg, Z. Anorg.
Allg. Chem., 1998, 624, 288–294.
8 (a) K. Frick, S. Verma, J. Sundermeyer and M. Hanack, Eur. J. Inorg.
Chem., 2000, 1025–1030; (b) S. Sievertsen and H. Homborg, Z. Anorg.
Allg. Chem., 1994, 620, 1439–1442.
Compound
1
Empirical formula
Formula weight
Crystal system
Space group
C36H39ClMoN9O7
841.15
Tetragonal
P4/n
13.8148(12)
13.8148(12)
10.0926(9)
1926.2(3)
2
1.450
0.469
12 104
1702
˚
a/A
˚
b/A
˚
9 S. Verma and M. Hanack, Z. Anorg. Allg. Chem., 2003, 629, 880–892.
10 J. C. Kim, W. S. Rees and V. L. Goedken, Inorg. Chem., 1995, 34,
2483–2486.
c/A
3
˚
V/A
Z
r
calcd/Mg m-3
11 L. M. Berreau, J. Chen and L. K. Woo, Inorg. Chem., 2005, 44, 7304–
m/mm-1
7306.
12 U. Radius and J. Attner, Eur. J. Inorg. Chem., 1999, 2221–2231.
13 M. Brown and C. Jablonski, Can. J. Chem., 2001, 79, 463–471.
14 G. Guillemot, E. Solari and C. Floriani, Organometallics, 2001, 20,
607–615.
15 C. Redshaw, X. Liu, S. Zhan, D. L. Hughes, H. Baillie-Johnson, M. R. J.
Elsegood and S. H. Dale, Eur. J. Inorg. Chem., 2008, 2698–2712.
16 W. Darwish, E. Seikel, R. Ka¨smarker, K. Harms and J. Sundermeyer,
J. Chem. Soc., Dalton Trans. accepted.
Reflections collected
Independent reflections
Rint
Reflections with I > 2s(I)
Goodness-of-fit on F2
R1 (observed data)
wR2 (all data)
0.0865
1424
1.100
0.0497
0.0978
17 (a) W. Darwish, K. Harms and J. Sundermeyer, Acta Crystallogr., Sect.
E: Struct. Rep. Online, 2005, 61, m1280; (b) W. Darwish, S. Schlecht, A.
Schaper, M. Fro¨ba, K. Harms, W. Massa and J. Sundermeyer, Z. Anorg.
Allg. Chem., 2009, 635, 1215–1224.
18 P. W. Dyer, V. C. Gibson, J. A. K. Howard, B. Whittle and C. Wilson,
Polyhedron, 1995, 14, 103–111.
2,3-Pc), 9.64–9.85 (m, 8 H, 1,4-Pc); APCI-MS (m/z) 832 [M+ -
C1], MALDI-TOF-MS (m/z) 868.0 [M+], 832.8 [M+ - Cl].
X-Ray crystallography
19 U. Radius, J. Sundermeyer and H. Pritzkow, Chem. Ber., 1994, 127,
1827–1835.
Selected crystallographic data of 1 are given in Table 4. The
complete data are given in the CIF file (ESI).† Data were
collected on a Stoe IPDS-II area detector system using a graphite
20 A. J. Nielson, Polyhedron, 1987, 6, 1657–1667.
21 K. Korn, A. Schorm and J. Sundermeyer, Z. Anorg. Allg. Chem., 1999,
625, 2125–2132.
22 (a) E. A. Lucia and F. D. Verderame, J. Chem. Phys., 1970, 52, 2307;
(b) M. Hanack, H. Heckmann and R. Polley, in Houben-Weyl, Methods
of Organic Chemistry, F: Aromatic and Heteroaromatic Large Rings,
Thieme, Stuttgart, 1997, 4, pp. 717–842.
23 W. Darwish, Preparation, Characterization and X-ray Crystal Structures
of New Axially Functionalized Phthalocyanines and Phthalocyanine
Modified SBA-15 Materials (Ph.D. thesis), Philipps-Universita¨t, Mar-
burg, 2006.
24 J. P. Collman, S. T. Harford, S. Franzen, T. A. Eberspacher, R. K.
Shoemaker and W. H. Woodruff, J. Am. Chem. Soc., 1998, 120, 1456–
1465.
˚
monochromated Mo-Ka X-radiation (l = 0.71073 A). The
structure was solved by direct methods (program SIR200233)
and refined on F2 by full matrix least squares using SHELXL-
97.34 All non hydrogen atoms were refined as anisotropic, the
hydrogen atom positions were calculated and refined using the
‘riding model’ with fixed isotropic thermal parameters. There
is a fourfold crystallographic disorder of the N-t-butyl group.
Disordered solvent has been refined introducing O-atoms of
disordered water molecules.
25 P. Basu, J. Chem. Educ., 2001, 78, 666–669.
26 M. K. Engel, in The Porphyrin Handbook: Phthalocyanines 20: Struc-
tural Characterization, ed. K. M. Kadish, R. Guilard and K. M. Smith,
Elsevier, 2003, pp.1–88 and references therein.
Acknowledgements
27 L. M. Berreau, V. G. Young and L. K. Woo, Inorg. Chem., 1995, 34,
Dr Darwish gratefully acknowledges advice and support from
Prof. Abd El-Ghaffar, NRC-Cairo.
3485–3490.
28 T. Diebold, B. Chevrier and R. Weiss, Inorg. Chem., 1979, 18, 1193–
1200.
29 R. Toreki, R. R. Schrock and W. M. Davis, J. Am. Chem. Soc., 1992,
114, 3367–3380.
References
30 P. Haisch, G. Winter, M. Hanack, L. Lu¨er, H.-J. Egelhaaf and D.
Oelkrug, Adv. Mater., 1997, 9, 316–321.
1 (a) C. C. Leznoff and A. B. P. Lever, Phthalocyanines, Properties
and Applications, Wiley-VCH, 1989; (b) D. Dini, M. Barthel and M.
Hanack, Eur. J. Org. Chem., 2001, 3759–3769; (c) M. Calvete, G. Y.
Yang and M. Hanack, Synth. Met., 2004, 141, 231–243; (d) M. Hanack
and M. Lang, Adv. Mater., 1994, 6, 819–833.
2 P. Gregory, J. Porphyrins Phthalocyanines, 2000, 4, 432–437.
3 Y. Shirota, J. Mater. Chem., 2000, 10, 1–25.
31 D. S. Terekhov, K. J. M. Nolan, C. R. McArthur and C. C. Leznoff,
J. Org. Chem., 1996, 61, 3034–3040.
32 K. Dehnicke and J. Stra¨hle, Angew. Chem., 1992, 104, 918–1000.
33 M. C. Burla, M. Camalli, B. Carrozzini, G. L. Cascarano, C.
Giacovazzo, G. Polidoria and R. Spagnab, J. Appl. Crystallogr., 2003,
36, 1103.
4 P.-C. Lo, X. Leng and D. K. P. Ng, Coord. Chem. Rev., 2007, 251,
2334–2353.
34 G. M. Sheldrick, SHELXS-97 and SHELXL-97, (1997) University of
Go¨ttingen, Go¨ttingen.
1188 | Dalton Trans., 2011, 40, 1183–1188
This journal is
The Royal Society of Chemistry 2011
©