Structurally adaptive multitopic ligands containing tris(pyrazolyl)methane units as supramolecular synthons: Manganese carbonyl complexes

Article abstract of DOI:10.1016/S0022-328X(02)02043-0

The compounds {p-C₆H₄[CH₂OCH₂ C(pz)₃]₂- [Mn(CO)₃]₂} (OTf)₂ (2, OTf^- = CF₃ SO₃^-), {m-C₆H₄ [CH₂OCH₂C(pz)₃] ₂[Mn(CO)₃]₂}(BF₄)₂ (3) and {1,2,4,5-C₆H₂[CH₂OCH₂ C-(pz)₃]₄[Mn(CO)₃]₄} (BF₄)₄ (4) have been prepared by reaction of the respective ligands with 'Mn (CO)₅^+,, prepared 'in situ' from the reaction of Mn(CO)₅Br and AgBF₄ or AgOTf in refluxing acetone. In the structures of all four complexes, the environment around the manganese atom is a slightly distorted octahedron, with the distortion caused by the restricted bite angle of the κ³-bonded tris(pyrazolyl)methane ligand. The structurally adaptive ligands in all four complexes support extended three-dimensional (3D) supramolecular structures. An important organizational feature for the three BF₄^- complexes is a double π-π and C-H?π interaction involving the pyrazolyl rings. The double π-π/-H?π interaction is intermolecular in 1 and 3 leading to the formation of chains and sheets. In the case of the tetratopic ligand in complex 4, the π-π/C-H?π interaction is intramolecular between adjacent (ortho) side arms. These supramolecular structures are also supported by weak C-H?F hydrogen bonds. For 3, classic π-π interactions of the central arene rings are also involved in organizing the 3D network. For 2, the structure is organized solely by C-H?O hydrogen bonding.

Full text of DOI:10.1016/S0022-328X(02)02043-0

Journal of Organometallic Chemistry 666 (2003) 87ꢃ101
/
www.elsevier.com/locate/jorganchem
Structurally adaptive multitopic ligands containing
tris(pyrazolyl)methane units as supramolecular synthons: manganese
carbonyl complexes
Daniel L. Reger *, Radu F. Semeniuc, Mark D. Smith
Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
Received 15 August 2002
Dedicated to Professor Jerry Atwood on the occasion of his 60th birthday
Abstract
The compounds {p-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}(BF4)2 (1, pzꢀ
/
pyrazolyl ring), {p-C6H4[CH2OCH2C(pz)3]2-
[Mn(CO)3]2}(OTf)2 (2, OTfꢁ ꢀCF3SO3ꢁ), {m-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}(BF4)2 (3) and {1,2,4,5-C6H2[CH2OCH2C-
/
(pz)3]4[Mn(CO)3]4}(BF4)4 (4) have been prepared by reaction of the respective ligands with ‘Mn(CO)5ꢂ’, prepared ‘in situ’ from the
reaction of Mn(CO)5Br and AgBF4 or AgOTf in refluxing acetone. In the structures of all four complexes, the environment around
the manganese atom is a slightly distorted octahedron, with the distortion caused by the restricted bite angle of the k3-bonded
tris(pyrazolyl)methane ligand. The structurally adaptive ligands in all four complexes support extended three-dimensional (3D)
supramolecular structures. An important organizational feature for the three BF4ꢁ complexes is a double pꢃ
interaction involving the pyrazolyl rings. The double pꢃp/CÃHÁ Á Áp interaction is intermolecular in 1 and 3 leading to the formation
of chains and sheets. In the case of the tetratopic ligand in complex 4, the pꢃp/CÃHÁ Á Áp interaction is intramolecular between
adjacent (ortho) side arms. These supramolecular structures are also supported by weak CÃHÁ Á ÁF hydrogen bonds. For 3, classic pꢃ
p interactions of the central arene rings are also involved in organizing the 3D network. For 2, the structure is organized solely by
/
p and CÃ
/
HÁ Á Áp
/
/
/
/
/
/
CÃ
/
HÁ Á ÁO hydrogen bonding.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: Tris(pyrazolyl)methane ligands; Manganese carbonyl complexes; Supramolecular structure
1. Introduction
preferences
of
the
coordinated
metal
ion
[1b,1c,1d,1e,1f,3]. The role of non-covalent interactions
is also recognized as providing organization into com-
plex networks. A wide variety of these interactions,
mainly involved with the anions [3a,3b,3c,3d,4] and the
solvents, [1h,3b,5] were found to have an impact on the
solid state organization of several compounds. Impor-
tant non-covalent interactions are strong [6] and weak
Investigations into the architecture of supramolecular
compounds formed by self-assembly processes have
been ongoing in the last two decades [1]. A growing
field in this area is the synthesis and characterization of
multidimensional architectures based on organometallic
building blocks [2]. The key features that determine the
overall structures of supramolecular assemblies are the
ligand topicity (i.e. the numbers and types of coordinat-
ing groups), flexibility or rigidity of the linker groups
joining the coordination sites and the stereochemical
[3e,7] hydrogen bonds, pꢃ
interactions (XꢀO, N, C) [9], and interhalogen inter-
actions [10].
/
p stacking, [8] XÃ
/
HÁ Á Áp
/
The way in which these organizational features
determine supramolecular structures still needs to be
clearly elucidated [11]. Our efforts in this area are based
on the chemistry of metal complexes of tris(pyrazo-
lyl)methane ligands (Plate 1) [12], a tripodal neutral
ligand set isoelectronic to the more heavily studied
* Corresponding author. Tel.: ꢂ
9521.
E-mail address: reger@mail.chem.sc.edu (D.L. Reger).
/
1-803-777-2587; fax: ꢂ1-803-777-
/
0022-328X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 2 0 4 3 - 0

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D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ101
/
2. Results and discussion
2.1. Synthesis of the compounds
The ligands were prepared as shown in Scheme 1. The
compounds {p-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}-
(BF4)2 (1), {p-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}-
(OTf)2 (2), {m-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}-
(BF4)2 (3) and {1,2,4,5-C6H2[CH2OCH2C(pz)3]4[Mn-
(CO)3]4}(BF4)2 (4) were obtained by reaction of the
ligands with ‘Mn(CO)5ꢂ’, prepared ‘in situ’ in refluxing
acetone, Scheme 2. Yellow solids were isolated from the
reaction mixture. All compounds are stable in air,
soluble in acetone, acetonitrile and nitromethane and
insoluble in chlorinated solvents or alcohols.
Plate 1.
tris(pyrazolyl)borate ligands [13]. We have reported
substantial improvements in the preparations of
tris(pyrazolyl)methane ligands [14] and developed chem-
istry of them where the central methine carbon atom can
be functionalized with groups other than a hydrogen
atom [14e].
Elemental analysis and electrospay mass spectrometry
confirmed the formulated stoichiometry. ESMS spectra
showed peaks corresponding to {L[Mn(CO)3]2BF4}ꢂ at
954 m/z or {L[Mn(CO)3]2CF3SO3}ꢂ at 1016 m/z and to
Using this chemistry, we have prepared multitopic
C6H6ꢁn-
{L[Mn(CO)3]}ꢂ at 728 m/z for Lꢀ
/
bitopic ligands*
/
ligands
of
the
general
formula
compounds 1, 2 and 3. In the case of 4, where L is the
tetratopic ligand, ESMS experiment revealed peaks at
1919, 1693, 1467 and 1241 m/z corresponding to
[CH2OCH2C(pz)3]n, (nꢀ
/
2, 4; pzꢀ
/
pyrazolyl ring). We
have reported that the reaction of the three isomers
ortho-, meta- and para-C6H4[CH2OCH2C(pz)3]2 with
[Cd2(THF)5](BF4)4 leads to the formation of coordina-
tion polymers of the formula {C6H4[CH2OCH2C(pz)3]2-
Cd(BF4)2}n, each with a different supramolecular struc-
ture even though they had the same octahedral coordi-
nation environment about the cadmium [15]. We have
shown that in similar coordination polymers of silver
important differences in the coordination mode of the
tris(pyrazolyl)methane units as well as on the overall
structure were observed [16] Further, the participation
{L[Mn(CO)3]4(BF4)3}ꢂ,
{L[Mn(CO)3]3(BF4)2}ꢂ,
{L[Mn(CO)3]2(BF4)}ꢂ and {L[Mn(CO)3]}ꢂ, respec-
tively.
The
double
charged
species
{L[Mn(CO)3]4(BF4)2}ꢂꢂ and {L[Mn(CO)3]2}ꢂꢂ were
also identified at 916 and 690 m/z, respectively. IR
spectra of all the complexes show two bands for the CO
ligand in the range 2055ꢃ
1940 cmꢁ1, suggesting an
/
octahedral coordination around the manganese atoms
with three fac CO ligands and the [C(pz)3] units acting
as tripodal ligands.
of pyrazolyl rings in pꢃ
interactions was observed to be an important organiza-
tional feature.
/
p stacking and CÃ
/
HÁ Á Áp
2.2. Solid state structures
We wished to explore the chemistry of the new
multitopic ligands with systems in which the metal was
bonded to other ligands that would prevent the forma-
tion of coordination polymers. Specifically, we desired a
metal system that prefers to bond to the tris(pyrazo-
lyl)methane units in a tripodal fashion and also has non-
labile ligands occupying the remaining coordination
sites (these preferences are called the ‘reading algorithm’
of the metal) [1i,1j]. Given our earlier preparation of
{[tris(pyrazolyl)methane]Mn(CO)3}ꢂ complexes [14d],
we chose [Mn(CO)3]ꢂ as the metal system. Reported
here is the chemistry and description of the solid state
structures of {p-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}-
(BF4)2 (1), {p-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}-
Crystals suitable for X-ray diffraction were grown by
vapor phase diffusion of diethyl ether into an acetoni-
trile solution of the compounds. Crystallographic data
and structure refinement parameters for compounds 1
and 2 are listed in Table 1 and for 3 and 4 in Table 2.
Selected bond lengths and angles are listed in Tables 3
and 4, respectively.
X-Ray analysis revealed that the structure of each
binuclear building block of 1 (Fig. 1) has the [tris(pyr-
azolyl)methane]Mn(CO)3 units located in a trans ar-
rangement above and below the plane of the arene ring.
The angle formed by the ring and the plane of the
attached CH2OCH2 group is 878. The environment
around the manganese atom is a slightly distorted
octahedron, with the distortion caused by the restricted
bite angle of the k3-bonded tris(pyrazolyl)methane
ligand.
(OTf)2 (2, OTfꢁ ꢀCF3SO3ꢁ), {m-C6H4[CH2OCH2C-
/
(pz)3]2[Mn(CO)3]2}(BF4)2 (3) and {1,2,4,5-C6H2[CH2O-
CH2C(pz)3]4[Mn(CO)3]4}(BF4)4 (4). All four complexes
have three-dimensional (3D) supramolecular structures
in the solid state. We have previously communicated the
interesting sinusoidal 3D architecture of 4 [17].
These homobimetallic building blocks are associated
into a more complex architecture by simultaneous
intermolecular pꢃ
/
p and CÃ
/
HÁ Á Áp interactions between

D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ
/
101
89
Scheme 1.
intrinsic geometry of the tris(pyrazolyl)methane units
makes this double interaction a highly favored arrange-
ment for the non-covalent forces.
The pyrazolyl rings in each tris(pyrazolyl)methane
unit of 1 form these types of pꢃ
/
p/CÃ
/
HÁ Á Áp interactions
with both neighboring units as pictured in Fig. 2a. The
˚
centroid distance, 3.61 A, is well
pyrazolyl ring centroidꢃ
below the maximum accepted distance (3.8 A) for pꢃ
interaction [8]. The third pyrazolyl ring that is not
involved in pꢃp stacking interactions acts as an acceptor
for both CÃH donor groups from the two pyrazolyl
rings involved in the pꢃp stacking. The CÃHꢃcentroid
distances of the associated CÃHÁ Á Áp interactions are
2.73 and 2.94 A and the corresponding CÃHꢃcentroid
angles are 145.1 and 133.88. These values are typical for
CÃ
/
˚
/
p
/
/
/
/
/
/
˚
/
/
/
HÁ Á Áp interactions [9]. These non-covalent forces
organize the bimetallic building blocks into stair-shaped
2D sheets, Fig. 2b.
Scheme 2.
two tris(pyrazolyl)methane units located in adjacent
binuclear building block, as shown in a general repre-
sentation in Scheme 3.
Arrangement of the [C(pz)3] units along the C3 axis in
the way depicted aligns two pyrazolyl rings so as to be
involved in a pꢃp interaction, with the nitrogen atoms
/
oriented in opposite directions so as to maximize the
attraction [8]. This orientation directs the hydrogen
atoms located at the 4-position of each pyrazolyl ring
involved in the pꢃ
pyrazolyl ring, forming a CÃ
/
p interaction toward to a second
/
HÁ Á Áp interaction. The
Scheme 3.

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D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ101
/
Fig. 1. ORTEP representation and numbering scheme of cationic part of {p-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}(BF4)2 (1).
Fig. 3a shows of how the sheets, oriented as in Fig.
2b, are joined in a 3D network by the BF4ꢁ groups
through weak CÃ
atom makes a bifurcated hydrogen bond with two
separate building blocks with the rest of the fluorine
atoms being involved each in only one hydrogen bond
with two additional building blocks. Fig. 3b shows the
interactions of one BF4ꢁ group bridging two of the
sheets. It also bridges two pairs of tris(pyrazo-
lyl)methane units within the sheets that are also involved
[Mn(CO)3]2}(BF4)2 into a 3D architecture. The channels
run at an oblique angle to the [010] direction in the unit
cell. The channels are filled with the guest solvent
/
HÁ Á ÁF hydrogen bonds. One fluorine
3
˚
molecules acetone and ether, occupying 1222 A from
3
˚
the total of 3073 A of the unit cell.
The complex {p-C6H4[CH2OCH2C(pz)3]2[Mn-
(CO)3]2}(OTf)2 (2), that contains the same binuclear
building block as 1 but a different counter-ion, has a
different structure, a structure that is also built by non-
covalent interactions. X-ray analysis of 2 revealed the
same octahedral arrangement of the [C(pz)3][Mn(CO)3]
units, Fig. 5. However, the side arms of the linking ether
groups are in a skewed position with respect to the arene
plane. The angle formed by the ring and the plane of the
attached CH2OCH2 group is 648 with the unusual
feature that both ether linkages are skewed in the
same direction (see also Fig. 6b), the first time we
have observed this type of arrangement [15,16]. In
in pꢃp interactions, strengthening the forces that join
/
the units into 2D sheets. The distances and angles of
these interactions are shown in Table 5. The average of
˚
the (C)HÁ Á ÁF values in Table 5 is nearly 0.2 A shorter
than the sum of the van der Waals radii for H and F
˚
atoms, 2.54 A [18].
˚
8 A channels formed by
the self-organization of {p-C6H4[CH2OCH2C(pz)3]2-
Fig. 4 is a view along the 11ꢄ
/
Fig. 2. The 2D sheet for 1 formed by intermolecular pꢃ
/
p/CÃ
/
HÁ Á Áp interactions: (a) view perpendicular on sheet; (b) view parallel to sheet, showing
the stair-like arrangement of the sheet.

D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ
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Fig. 3. (a) Space filling representation of the 3D network for 1 formed via week CÃ
/
HÁ Á ÁF hydrogen bonds; (b) CÃ
/
HÁ Á ÁF intermolecular interactions
for one BF4ꢁ bridging two pairs of tris(pyrazolyl)methane units (also involved in pꢃ
/
p interactions) in each sheet and also bridging two of the sheets.
contrast to 1, there are no pꢃ
/
p stacking or CÃ
/
HÁ Á Áp
pair of pz rings the centroidꢃcentroid distance is of 3.38
/
˚
˚
interactions between the [C(pz)3] units. Since all other
conditions in the preparation and crystallization of 2
were identical as for 1 (method of crystallization,
solvents, temperature), the exchange of BF4ꢁ for
CF3SO3ꢁ anions dramatically alters the non-covalent
interactions. Because the oxygen atoms from the
CF3SO3ꢁ anion can form stronger hydrogen bonds
than fluorine atoms from the BF4ꢁ anion, the dominate
A and the H(12)ꢃ
/
centroid distance is 2.90 A, with a CÃ
/
Hꢃcentroid angle of 143.58. For the second pair the
/
˚
same distances are 3.66, 2.86 A and 140.98, respectively.
Fig. 8a is a view perpendicular to one corrugated chain,
showing the pꢃ
/
p stacking component of one double pꢃ
/
p/CÃ
/
HÁ Á Áp interaction. The chains run along the body
diagonal of the unit cell (crystallographic [111] direc-
tion), as can be seen in Fig. 8b. A third pair of pyrazolyl
non-covalent force in 2 is CÃ
/
HÁ Á ÁO hydrogen bonding
rings is involved in another pꢃ
/
p/CÃ
/
HÁ Á Áp interaction,
[19]. Unfortunately, the triflate anions were found to be
disordered and a precise assessment of these interactions
cannot be made. However, the three views of the overall
structure shown in Fig. 6, each oriented 908 with respect
to one another, indicate an interesting supramolecular
structure organized by the triflate anions. A similar
domination of the non-covalent forces by the triflate
anion has been observed in the structure of [{p-
C6H4[CH2OCH2C(pz)3]2Ag2}(OTf)2]n [20].
with the corresponding geometric parameters of 3.72,
˚
2.96 A and 137.68. This last interaction organizes the
Single crystal X-ray analysis of {m-C6H4[CH2O-
CH2C(pz)3]2[Mn(CO)3]2}(BF4)2 (3), the meta isomer of
1, revealed that the binuclear organometallic building
block has both [C(pz)3][Mn(CO)3] units on the same side
of the central arene ring, Fig. 7. Again, the environment
around the manganese atom is a slightly distorted
octahedron, with the distortion caused by the restricted
bite angle of the k3-bonded tris(pyrazolyl)methane
ligand. Details on the geometric parameters of the
cationic unit can be found in Table 4.
The supramolecular structure of 3 is based almost
entirely on pꢃ
/
p stacking and CÃ
/
HÁ Á Áp interactions.
First, two pairs of pyrazolyl rings are involved in two
separate interactions, connecting the building blocks
head to tail into corrugated chains. The corresponding
values for the interactions are as follows: for the first
Fig. 4. View for 1 along the channels formed by the 3D architecture;
solvent molecules are not shown.

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D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ101
/
Fig. 5. ORTEP representation and numbering scheme of cationic part of {p-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}(OTf)2 (2).
chains into a 2D sheet of chains. Two chains showing
one connection between the chains are pictured in Fig.
9a, with Fig. 9b being a view end-on to that of Fig. 9a.
An interesting structural feature of 3 is that the
building block within one sheet and another one with a
building block next to the one involved in the ‘classic’
pꢃp stacking from a neighboring sheet, contributing in
/
this manner to the strength that organize the sheets into
a 3D structure, Fig. 11.
central arene ring is involved in a classic pꢃp interaction
/
organizing the 2D sheets into a 3D network. The
placement of both side arms of any bimetallic building
block on the same side of the central arene ring allows
an arrangement where two arene rings from different
sheets are situated one above another and parallel
displaced, orienting the side arms in opposite directions,
Crystals of the manganese complex of the tetratopic
ligand have the formula {C6H2[CH2OCH2C(pz)3]4[Mn-
(CO)3]4}(BF4)4×
/
6CH3CN×/2C4H10O (4). Single crystal
X-ray analysis shows that as in the other cases, each
of the tris(pyrazolyl)methane units of the ligand is k3-
bonded to a [Mn(CO)3]ꢂ cation forming a distorted
octahedral arrangement around the manganese(I), Fig.
12. The overall structure of the centrosymmetric tetra-
metallic building block is surprising in that the ortho-
bonded ligand side arms are on the same side of the
connecting arene ring. In the structures of o-
Fig. 10a. This offset leads to a long centroidꢃ
/
centroid
distance (4.13 A) but with a short perpendicular distance
˚
˚
between the planes of 3.64 A. Fig. 10b shows that the
BF4ꢁ anions are also involved in the organization of 3
into a 3D architecture. Each BF4ꢁ makes two hydrogen
bonds (the values are listed in Table 5), one with a
C6H4[CH2OCH2C(pz)3]2
and
1,2,4,5-C6H2[CH2O-
Fig. 6. Extended structures of 2: (a) six cationic binuclear building blocks aligned perpendicular to b axis of the unit cell; triflate anions not shown;
(b) the same six building blocks viewed down c axis showing the skewed trans position with respect to the central arene plane and the position of the
triflate anions; (c) view down b axis showing the stair-like shape of the building blocks.

D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ
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Fig. 7. ORTEP representation and numbering scheme of cationic part of {m-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}(BF4)2 (3).
CH2C(pz)3]4 and the coordination polymers {o-
C6H4[CH2OCH2C(pz)3]2Cd(BF4)2}n and {1,2,4,5-
As shown in Fig. 13, the tetrametallic building blocks
are organized into a 3D architecture by weak CÃ
/
HÁ Á ÁF
hydrogen bonds. The supramolecular structure of 1 is a
sinusoidal like ‘function’ with respect to the b axis; the
C6H2[(CH2OCH2C(pz)3]4Ag2(BF4)2}n, adjacent side-
arms are on opposite sides of the central arene ring
[15,16a]. The driving force for the same side organiza-
‘wave length’*/measured between three consecutive
phenyl centroids from the same sheet*
/
is equal to the
tion observed here is an intramolecular pꢃ
/
p/CÃ
/
HÁ Á Áp
ꢁ
˚
b axis, 17.6246(13) A. There are two BF4 anions per
asymmetric unit; both are involved in weak hydrogen
bonds with different organizational functions. One is
involved in organizing the tetrametallic building blocks
into 2D corrugated sheets and the second organizes the
sheets into a 3D network.
interaction, between two pyrazolyl rings located on
adjacent arms. The perpendicular distance between the
˚
pyrazolyl rings planes is 3.50 A and the centroidꢃ
/
˚
centroid distance is 3.53 A. The corresponding CÃ
/
˚
HÁ Á Áp geometric parameters are 2.66 A for the Hꢃ
/
centroid distance with a CÃHꢃcentroid angle of 141.38
/
/
˚
for the first pair of side arms and 2.63 A and 140.98,
respectively, for the second pair. The pairs of adjacent
arms are on opposite sides of the arene ring yielding an
overall stepped structure for each tetrametallic building
block.
3. Conclusion
We have prepared and characterized in the solid state
four complexes containing octahedral [C(pz)3][Mn-
Fig. 8. One corrugated chain constructed by 3: (a) view perpendicular to the chain; (b) view along the chain.

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D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ101
/
Fig. 9. The association of two chains for 3 into a 2D network: (a) the double pꢃ
represented by double dotted/single dotted lines. The dots (m) shows where the double pꢃ
(b) view perpendicular to the two connected chains in the same orientation as in Fig. 8b.
/
p/CÃ
p/CÃ
/
HÁ Á Áp interaction that organize the chains into sheets,
/
/
HÁ Á Áp interaction forms the chains presented in Fig. 8;
(CO)3] units linked by organic spacers into multinuclear
organometallic building blocks. All four organometallic
building blocks are organized into complex supramole-
cular architectures by non-covalent forces. Three of the
structures, those with BF4ꢁ counter-ions, display an
involved in the stacking are also associated with a CÃ
/
HÁ Á Áp interaction. This double pꢃ
/
p/CÃ
/
HÁ Á Áp interaction
is an intrinsic feature of adjacent tripodal tris(pyrazo-
lyl)methane units oriented along the C3 axis.
There are several conditions that must be fulfilled to
observe this interaction. First, the metallic center must
interesting pꢃp stacking in which the pyrazolyl rings
/
Fig. 10. Organization of 3 into a 3D architecture: (a) classic pꢃ
(b) the same two building blocks viewed after a 908 rotation; the dotted lines represent weak CÃ
the cationic building blocks involved in the classic pꢃ
/
p stacking between two cationic building blocks represented by the double dotted line;
/
HÁ Á ÁF hydrogen bonds between four BF4ꢁ units and
/
p stacking; the arrows indicate the direction of the second CÃ
toward other units (not shown) that are part from different sheets; the orientation of the building blocks is the same as in Fig. 8b and Fig. 9b.
/
HÁ Á ÁF hydrogen bond directed

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101
95
Fig. 11. The overall supramolecular structure of 3 viewed along the body diagonal of the unit cell; for the sake of clarity anions are not shown.
have three open coordination sites so that the [C(pz)3]
unit can act as a tripodal ligand. In previously reported
silver coordination polymers based on these same
such a double interaction. Other arrangements of pꢃ
/
p
stacking or CÃ
/
HÁ Á Áp interactions were found to be
important organizational tools in those systems, but not
the double arrangement observed here for complexes 1,
3 and 4. The formation of individual multimetallic
ligands [16a,16b,16c], a k2ꢃk1 coordination mode of
/
the tris(pyrazolyl)methane unit was observed preventing
Fig. 12. ORTEP representation and numbering scheme of cationic part of {1,2,4,5-C6H2[CH2OCH2C(pz)3]4[Mn(CO)3]4}(BF4)2 (4).

96
D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ
/
101
Fig. 13. The supramolecular structure of 4 along the b axis.
building blocks, rather than coordination polymers, is
also important. In the cadmium coordination polymers
of these ligands this double interaction is absent, in spite
of the fact that the ligands act as tripodal ligands [15].
The counter-ion is also an important factor for the
we show here, the presence of the triflate anion appears
to prevent the double association of the building blocks,
presumably due to their greater capacity of establishing
weak hydrogen bonds.
The orientation of the [C(pz)3] units within the
individual ligands, i.e. ligand topology, also has an
formation of this double pꢃ
/
p/CÃ
/
HÁ Á Áp interaction. As
Table 1
Crystallographic data and structure refinement parameters for {p-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}(BF4)2 (1) and {p-
C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}(OTf)2 (2)
1
2
Empirical formula
Formula weight
Temperature (K)
Crystal system
Space group
C36H30B2F8Mn2N12O8
1042.22
173(2)
C42H40F6Mn2N12O15S2
1240.86
293(2)
Monoclinic
P21/c
Monoclinic
C2/c
˚
a (A)
11.797(3)
13.229(3)
20.322(5)
104.299(4)
3073.4(12)
2
22.9560(13)
12.8233(7)
20.0778(11)
116.1960(10)
6945.0(9)
4
˚
b (A)
˚
c (A)
b (8)
Volume (A )
3
˚
Z
Density (calc.) (Mg mꢁ3
Absorption coefficient (mmꢁ1
F(000)
)
1.126
0.481
1052
1.554
0.652
2528
)
Crystal size (mm)
0.46ꢄ
11 441
4272 [Rint
/
0.20ꢄ
/
0.10
0.48ꢄ
24 054
5420 [Rint
/
0.28ꢄ
/
0.08
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
ꢀ
/
0.0861]
ꢀ
/
0.0555]
4272/0/307
0.941
5420/43/418
0.975
Final R indices [I ꢀ
/
2s(I)]
R1ꢀ/0.0953, wR2ꢀ/0.2518
R1ꢀ/0.0572, wR2ꢀ/0.1417
R indices (all data)
R1ꢀ/0.1379, wR2ꢀ/0.2720
R1ꢀ/0.0847, wR2ꢀ/0.1548

D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ
/
101
97
Table 2
Crystallographic data and structure refinement parameters for {m-C6H4[CH2OCH2C(pz)3]2[Mn(CO)3]2}(BF4)2 (3) and {1,2,4,5-
C6H2[CH2OCH2C(pz)3]4[Mn(CO)3]4}(BF4)2 (4)
3
4
Empirical formula
Formula weight
Temperature (K)
Crystal system
Space group
C
36H30B2F8Mn2N12O8
C86H92B4F16Mn4N30O18
2400.90
173(2)
1042.22
190(2)
Triclinic
Monoclinic
P21/c
¯
P1
˚
a (A)
11.7634(8)
12.4354(8)
15.8356(11)
100.856(2)
99.313(2)
103.9400(10)
2155.2(3)
2
11.8441(9)
17.6246(13)
25.6874(19)
90
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
99.538(2)
90
3
˚
Volume (A )
Z
Density (calc.) (Mg mꢁ3
Absorption coefficient (mmꢁ1
F(000)
5288.1(7)
2
1.508
)
1.606
0.686
1052
)
0.573
2452
Crystal size (mm)
0.32ꢄ
16 763
6968 [Rint
/
0.20ꢄ
/
0.08
0.40ꢄ
34 997
10 830 [Rint
/
0.24ꢄ
/
0.20
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
ꢀ
/
0.0531]
ꢀ
/
0.0395]
6968/0/613
1.011
10 830/6/712
1.042
Final R indices [I ꢀ
/
2s(I)]
R1ꢀ/0.0601, wR2ꢀ/0.1216
R1ꢀ/0.0688, wR2ꢀ/0.2000
R indices (all data)
R1ꢀ/0.0961, wR2ꢀ/0.1319
R1ꢀ/0.0938, wR2ꢀ/0.2164
important impact on the overall supramolecular struc-
ture. In two cases, the double pꢃp/CÃ
is intermolecular and leads to the formation of chains
(stair-like or corrugated) is determined by the position
of the side arms on the central arene ring. In the case of
/
/
HÁ Á Áp interaction
the tetratopic ligand, the pꢃ
/
p/CÃ
/
HÁ Á Áp interaction is
intramolecular between adjacent (ortho) side arms with
the counter-ions organizing the building blocks into a
3D network. Our results show that this new class of
multitopic ligands, based on tris(pyrazolyl)methane
units linked by flexible organic spacers, are structurally
adaptive showing a variety of shapes that can accom-
modate various reading algorithms of different metal
systems and maximize non-covalent forces. This struc-
turally adaptive feature of the ligands makes them
versatile synthons in supramolecular chemistry.
and sheets. In these two cases, the shape of the sheets
Table 3
˚
Selected bonds (A) and angles (8) for 1 and 2
Atoms
1
2
Bond lengths
MnÃ
MnÃ
MnÃ
MnÃ
MnÃ
MnÃ
/
N(11)
N(21)
N(31)
C(41)
C(42)
C(43)
1.997(6)
2.044(5)
2.042(6)
1.771(9)
1.782(11)
1.806(9)
2.043(3)
2.033(3)
2.045(3)
1.810(4)
1.821(4)
1.810(5)
/
/
/
/
/
4. Experimental
Bond angles
N(11)ÃMnÃ
N(11)ÃMnÃ
N(21)ÃMnÃ
C(41)ÃMnÃ
C(41)ÃMnÃ
C(42)ÃMnÃ
C(41)ÃMnÃ
C(42)ÃMnÃ
C(43)ÃMnÃ
C(41)ÃMnÃ
C(42)ÃMnÃ
C(43)ÃMnÃ
C(41)ÃMnÃ
C(42)ÃMnÃ
C(43)ÃMnÃ
/
/
N(21)
N(31)
N(31)
83.7(2)
83.2(2)
83.8(2)
88.4(4)
89.6(4)
93.9(4)
178.0(3)
93.6(4)
90.6(3)
94.3(3)
173.9(3)
91.6(3)
96.4(4)
90.5(3)
172.6(3)
85.02(10)
83.23(10)
83.99(10)
90.91(17)
92.57(19)
91.3(2)
4.1. General procedure
/
/
/
/
/
/
C(42)
C(43)
C(43)
N(11)
N(11)
N(11)
N(21)
N(21)
N(21)
N(31)
N(31)
N(31)
All operations were carried out under a nitrogen
atmosphere using standard Schlenk techniques and a
Vacuum Atmospheres HE-493 dry box. All solvents
/
/
/
/
/
/
174.14(13)
92.81(15)
91.86(16)
91.09(14)
176.94(16)
90.89(16)
92.02(15)
93.63(16)
173.18(15)
1
were dried, degassed, and distilled prior to use. The H-
/
/
NMR spectra were recorded on a Varian AM300
spectrometer using a broad-band probe. Proton chemi-
cal shifts are reported in ppm versus internal Me4Si.
Mass spectral data were recorded on a MicroMass
QTOF spectrometer. Clusters assigned to specific ions
show appropriate isotopic patterns as calculated for the
atoms present. The bitopic ligands were prepared
/
/
/
/
/
/
/
/
/
/
/
/
/
/

98
D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ101
/
Table 4
Table 5
Hydrogen bonding parameters for compounds 1, 2, 3 and 4
˚
Selected bonds (A) and angles (8) for 3 and 4
3
4
Atoms
CÁ Á ÁA
HÁ Á ÁA
CÃ
/
HÁ Á ÁA
Bond lengths
Compound 1
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
/
N(11)
N(21)
N(31)
C(14)
C(24)
C(34)
N(41)
N(51)
N(61)
C(44)
C(54)
C(64)
2.045(4)
2.052(4)
2.050(4)
1.817(6)
1.798(6)
1.808(6)
2.029(4)
2.044(4)
2.037(4)
1.798(6)
1.817(6)
1.770(6)
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
/
N(11)
N(21)
N(31)
C(81)
C(82)
C(83)
N(41)
N(52)
N(62)
C(91)
C(92)
C(93)
2.051(3)
2.039(3)
2.035(3)
1.818(5)
1.832(4)
1.809(5)
2.043(3)
2.033(3)
2.046(3)
1.837(4)
1.827(5)
1.810(5)
C(13)Ã
C(21)Ã
C(2)ÃH(2B)Ã
C(22)ÃH(23)Ã
C(2)ÃH(2A)Ã
/
H(13)Ã
/
F(3)
3.33
3.21
3.33
3.21
3.26
2.45
2.31
2.36
2.27
2.34
154.8
156.6
165.5
169.3
153.5
/
/
/
H(21)Ã
/F(4)
/
/
/
/F(2)
/
/
/
/
F(1)
/
/
/
/
F(1)
/
/
Compound 2
C(2)ÃH(2A)Ã
C(2)ÃH(2A)Ã
/
/
/
/
O(52)
O(52)
3.24
3.28
2.39
2.35
145.9
161.6
/
/
/
/
/
/
Compound 3
C(13)ÃH(13)Ã
C(51)ÃH(51)Ã
C(33)ÃH(33)Ã
C(41)ÃH(41)Ã
/
/
/
/
F(3)
F(1)
F(7)
F(5)
3.29
3.05
3.20
3.35
2.38
2.32
2.34
2.41
158.3
132.5
150.1
169.5
/
/
/
/
/
/
/
/
Bond angles
N(11)ÃMn(1)Ã
N(11)ÃMn(1)Ã
N(31)ÃMn(1)Ã
C(24)ÃMn(1)Ã
C(34)ÃMn(1)Ã
C(24)ÃMn(1)Ã
C(14)ÃMn(1)Ã
C(24)ÃMn(1)Ã
C(34)ÃMn(1)Ã
C(14)ÃMn(1)Ã
C(24)ÃMn(1)Ã
C(34)ÃMn(1)Ã
C(14)ÃMn(1)Ã
C(24)ÃMn(1)Ã
C(34)ÃMn(1)Ã
N(41)ÃMn(2)Ã
N(41)ÃMn(2)Ã
N(61)ÃMn(2)Ã
C(64)ÃMn(2)Ã
C(64)ÃMn(2)Ã
C(44)ÃMn(2)Ã
C(44)ÃMn(2)Ã
C(54)ÃMn(2)Ã
C(64)ÃMn(2)Ã
C(44)ÃMn(2)Ã
C(54)ÃMn(2)Ã
C(64)ÃMn(2)Ã
C(44)ÃMn(2)Ã
C(54)ÃMn(2)Ã
C(64)ÃMn(2)Ã
/
/
/
/
N(21)
N(31)
N(21)
82.39(14) N(11)Ã
85.02(14) N(11)Ã
84.15(14) N(21)Ã
/
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
Mn(1)Ã
83.30(16) N(41)ÃMn(2)Ã
84.77(15) N(41)ÃMn(2)Ã
83.75(15) N(52)ÃMn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
Mn(2)Ã
/
N(21)
N(31)
N(31)
C(82)
C(83)
C(83)
83.46(12)
83.56(13)
84.15(12)
90.1(2)
Compound 4
C(11)ÃH(11)Ã
C(13)ÃH(13)Ã
C(51)ÃH(51)Ã
C(53)ÃH(53)Ã
C(77)Ã
C(31)Ã
C(41)Ã
C(72)Ã
C(77)Ã
/
/
/
/
/
/
F(3)
F(4)
F(2)
F(4)
3.23
3.27
3.10
3.25
3.22
3.15
3.16
3.12
3.29
2.40
2.36
2.32
2.35
2.25
2.24
2.34
2.37
2.46
146.0
158.6
138.3
158.4
168.5
158.5
143.9
132.0
141.1
/
/
/
/
/
/
/
/
C(14)
C(14)
C(34)
91.1(2)
90.1(2)
92.0(2)
C(81)Ã
C(81)Ã
C(82)Ã
C(81)Ã
92.38(18) C(82)Ã
/
/
/
/
/
/
/
/
90.5(2)
/
/
/
/
/
/
91.1(2)
/
H(77B)Ã
/F(1)
/
/
N(11) 176.0(2)
/
/
N(11) 175.12(16)
/
H(31)Ã
/
F(5)
/
/
N(11)
N(11)
N(21)
/
/
N(11)
N(11)
N(21)
93.80(18)
92.28(17)
92.37(15)
/
H(41)Ã
/
F(6)
/
/
91.8(2)
C(83)Ã
/
/
/
H(72B)Ã
/F(5)
/
/
93.9(2)
C(81)Ã
/
/
/
H(77A)Ã
/F(6)
/
/
N(21) 171.61(18) C(82)Ã
/
/
N(21) 174.46(17)
/
/
N(21)
N(31)
N(31)
94.70(19) C(83)Ã
93.1(2)
C(81)Ã
88.88(19) C(82)Ã
/
/
N(21)
N(31)
N(31)
93.80(16)
93.53(16)
90.78(17)
/
/
/
/
/
/
/
/
yield of the final product. The solution was allowed to
cool to room temperature and water (150 ml) was added
to consume the excess of NaH and dissolve the salts
formed in the reaction. The organic layer was separated,
/
/
N(31) 176.69(19) C(83)Ã
/
/
N(31) 175.54(17)
/
/
N(51)
N(61)
N(51)
/
/
N(52)
N(62)
N(62)
84.09(12)
83.40(12)
83.78(12)
90.82(19)
91.4(2)
/
/
/
/
/
/
/
/
/
/
C(44)
C(54)
C(54)
92.8(2)
88.5(2)
93.5(2)
C(91)Ã
C(91)Ã
C(92)Ã
C(91)Ã
C(91)Ã
C(91)Ã
/
/
C(92)
C(93)
C(93)
the aqueous layer extracted with ether (3ꢄ 100 ml) and
/
/
/
/
/
the combined organic extracts were washed with a
saturated NaHCO3 solution (200 ml) and with water
(200 ml). The organic phase was dried (Na2SO4), filtered
and the solvent removed in vacuo yielding an off white
solid (3.34 g, 76%). ESꢂMS: for [C54H54N24O4Na]ꢂ
Calc.: 1125.4658. Found: 1125.4657; 1H-NMR (acetone-
d6 300 Hz): d 7.61, 7.46 (d of d, 12,12H, 3,5-H pz), 7.04
(s, 2H, C6H2), 6.34 (d of d, 12H, 4-H pz), 5.08 (s, 8H,
OCH2pz), 4.46 (s, 8H, OCH2C(Ph)3).
/
/
/
/
90.1(2)
/
/
N(41) 175.2(2)
/
/
N(41) 173.78(16)
/
/
N(41)
N(41)
N(61)
N(61)
90.9(2)
89.2(2)
/
/
N(52)
N(62)
N(41)
93.11(16)
90.79(17)
91.90(16)
/
/
/
/
/
/
93.11(19) C(92)Ã
93.5(2)
/
/
/
/
C(92)Ã
/
/
N(52) 175.95(16)
/
/
N(61) 173.65(19) C(92)Ã
N(51) 92.2(2)
C(93)Ã
N(51) 173.8(2)
C(93)Ã
N(51) 93.6(2)
C(93)Ã
/
/
N(62)
N(41)
N(52)
95.20(19)
94.19(16)
90.81(17)
/
/
/
/
/
/
/
/
/
/
/
/
N(62) 174.26(17)
4.3. Synthesis of {p-C6H4[CH2OCH2C(pz)3]2-
[Mn(CO)3]2}(BF4)2 (1)
following
(BrCH2)2C6H2, AgBF4, AgCF3SO3 and Mn(CO)5Br
were purchased from SigmaꢃAldrich and used without
further purifications.
literature
methods
[15].
1,2,4,5-
/
A mixture of Mn(CO)5Br (0.275 g, 1.0 mmol) and
AgBF4 (0.194 g, 1.0 mmol) was dissolved in acetone (50
ml). The solution was heated at reflux for 1 h and the
yellow solution was cannula filtered into a solution of p-
C6H4[CH2OCH2C(pz)3]2 (0.295 g, 0.50 mmol) in ace-
tone (50 ml). The resulting mixture was heated at reflux
for 2 h and then stirred for another 2 h. Removal of the
solvent yielded a yellow solid (0.374 g, 36%), melting
4.2. Synthesis of 1,2,4,5-C6H2[(CH2OCH2C(pz)3]4
To a stirred suspension of NaH (1.2 g, 50 mmol) in
THF (250 ml) was added dropwise a mixture of 1,2,4,5-
(CH2Br)4C6H2 (1.8 g, 4.0 mmol) and HOÃ
/CH2C(pz)3
(3.9 g, 16 mmol) in THF (100 ml). The solution was
heated at reflux for 5 h. Longer reaction times resulted
in a darkening of the solution and a subsequent lower
point (m.p.)ꢀ
Calc. for
(BF4)]ꢂ: 954.1136. Found: 954.1168. 1H-NMR (ace-
/
163 8C with decomposition. ESꢂMS:
[{p-C6H4[CH2OCH2C(pz)3Mn(CO)3]2}-

D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ
/
101
99
tone-d6, all br): d 8.67, 8.60 (6,6H, 3,5-H pz), 7.61 (4H,
C6H4), 6.73 (6H, 4-H pz), 5.93 (4H, OCH2C(pz)3), 5.23
using inert oil for data collection at low temperature.
Compound 2 was epoxied onto the tip of a glass fiber
for room temperature data collection. X-ray intensity
data were measured on a Bruker SMART APEX CCD-
(4H, OCH2Ph). IR (Nujol) nCO: 2053, 1943 cmꢁ1
.
4.4. Synthesis of {p-C6H4[CH2OCH2C(pz)3]2-
[Mn(CO)3]2}(OTf)2 (2)
based diffractometer (Moꢃ
/
Ka radiation, lꢀ
A). Raw data frames were integrated and corrected for
Lorentz and polarization effects with SAINT [21]. Final
unit cell parameters are based on the least-squares
refinement of all data with I ꢀ5s(I) from each data
/
0.71073
˚
ꢂ
/
This compound was prepared as above for 1 using
0.256 g of AgCF3SO3 instead of AgBF4. The procedure
/
yielded 0.382 g (66%) of 2, m.p.ꢀ182 8C with decom-
/
set (2501 for 1, 7474 for 2, 4994 for 3, and 6214 for 4).
Analysis of identical reflections measured at the begin-
ning and end of data collection showed negligible crystal
decay during collection for each crystal. Empirical
absorption corrections were applied with the program
SADABS [21]. All structures were solved by a combina-
tion of direct methods and difference Fourier synthesis,
and refined against F2 using all data (SHELXTL [22]).
Compound 1 decomposes almost instantaneously
upon removal from the crystallization solvent due to
rapid solvent loss (vide infra). Several attempts to
transfer crystals rapidly from the mother liquor to the
diffractometer cold stream were made, however, the best
crystal of 1 still showed visible evidence of degradation
(cracking and clouding), and broader than ideal diffrac-
tion maxima. 1 crystallizes in the space group P21/c as
determined from the systematic absences in the intensity
data. The [Mn(CO)3(C30H30N12O2)Mn(CO)3]2ꢂ cation
resides on a crystallographic inversion center. After
location of all atoms of the cation and anion, a region of
highly diffuse electron density remained, presumably
included solvent molecules. After several attempted
disorder models, the SQUEEZE [23] option in the
program PLATON [24] was used to account for the
disordered species. SQUEEZE calculated a solvent-
position. Calc. for C38H30F6Mn2N12O14S2: C, 39.12; H,
1
2.59. Found: C, 39.54; H, 2.31%. H-NMR (acetone-d6,
all br.): d 8.70, 8.63 (6,6H, 3,5-H pz), 7.65 (4H, C6H4),
6.70 (6H, 4-H pz), 5.90 (4H, OCH2C(pz)3), 4.98 (4H,
OCH2Ph). IR (Nujol) nCO: 2054, 1945 cmꢁ1
.
4.5. Synthesis of {m-C6H4[CH2OCH2C(pz)3]2-
[Mn(CO)3]2}(BF4)2 (3)
This compound was prepared as above for 1 using
0.295 g of m-C6H4[CH2OCH2C(pz)3]2 instead of p-
C6H4[CH2OCH2C(pz)3]2. The procedure yielded 0.373
g (36%) of 3, m.p.ꢀ198 8C with decomposition.
/
ESꢂMS: Calc. for [{m-C6H4[CH2OCH2C(pz)3Mn-
(CO)3]2}(BF4)]ꢂ: 955.1106. Found: 955.1082; 1H-
NMR (acetone-d6, all br): d 8.52, 8.47 (6,6H, 3,5-H
pz), 7.77, 7.46, 7.33 (m, 4H, C6H4), 6.55 (6H, 4-H pz),
5.78 (4H, OCH2C(pz)3), 5.10 (4H, OCH2Ph). IR (Nujol)
nCO: 2052, 1947 cmꢁ1
.
4.6. Synthesis of {1,2,4,5-C6H2[CH2OCH2C(pz)3]4-
[Mn(CO)3]4}(BF4)2 (4)
A mixture of Mn(CO)5Br (0.22 g, 0.8 mmol) and
AgBF4 (0.156 g, 0.8 mmol) were dissolved in acetone (50
ml). The solution was heated at reflux for 1 h and the
yellow solution was transferred via cannula over a
suspension of 1,2,4,5-C6H2[CH2OCH2C(pz)3]4 (0.22 g,
0.2 mmol) in acetone (50 ml). The resulting mixture was
heated at reflux for 2 h as the ligand dissolved. After
additional heating (3 h) a yellow compound precipitated
3
˚
accessible void volume of 1221.8 A per cell, corre-
sponding to 262 electrons. The contribution of these
electrons was subsequently removed from the structure-
factor calculations. Note that the molecular weight,
calculated density and F(000) value reflect known
species only. Eventually, all non-hydrogen atoms were
refined with anisotropic displacement parameters; hy-
drogen atoms were placed in geometrically idealized
positions and refined as riding atoms.
that was filtered (0.256 g 62%), m.p.ꢀ225 8C with
/
decomposition. Calc. for C66H54B4F16Mn4N24O16: C,
1
39.51; H, 2.71. Found: C, 39.16; H, 3.19%. H-NMR
Systematic absences and intensity statistics for 2
indicated the monoclinic space group C2/c, which was
confirmed. The [(CO)3Mn(C30H30N12O2)Mn(CO)3]2ꢂ
cation and one diethyl ether molecule of crystallization
are both situated on 2-fold rotational axes. The triflate
counter-ion is severely disordered, and was modeled as
occupying two orientations in a 70/30 proportion,
subject to several geometric restraints (SHELX DFIX
and SAME). The elongated displacement parameters for
the triflate indicate more severe disorder is likely
present. Eventually all non-hydrogen atoms were refined
with anisotropic displacement parameters; hydrogen
(CD3CN, all br): d 8.20, 8.11 (12,12H, 3,5-H pz) 7.99
(2H, C6H2), 5.95 (12H, 4-H pz), 5.48 (8H, OCH2C(pz)3),
5.25 (8H, OCH2Ph). IR (Nujol) nCO: 2051, 1943 cmꢁ1
.
5. Crystallographic studies
Crystal, data collection and refinement parameters
are given in Tables 1 and 2. Single crystals of 1, 2, 3 and
4 were grown by vapor phase diffusion of diethyl ether
into an acetonitrile solution of the compounds. Suitable
crystals of 1, 3 and 4 were mounted onto thin glass fibers

100
D.L. Reger et al. / Journal of Organometallic Chemistry 666 (2003) 87ꢃ101
/
1461;
atoms were placed in geometrically idealized positions
and refined as riding atoms.
Compound 3 crystallizes in the triclinic system. The
(f) P. Nguyen, P. Gomez-Elipe, I. Manners, Chem. Rev. 99 (1999)
1515;
(g) S. Leininger, B. Olenyuk, P.J. Stang, Chem. Rev. 100 (2000)
853;
¯
space group P1 was assumed and confirmed by success-
/
ful solution and refinement of the structure. All atoms
are on positions of general crystallographic symmetry,
and the cation possesses no crystallographically imposed
symmetry. Non-hydrogen atoms were refined with
anisotropic displacement parameters; hydrogen atoms
were placed in geometrically idealized positions and
refined as riding atoms.
Compound 4 crystallizes in the monoclinic space
group P21/c as determined by the systematic absences
in the data set. The {1,2,4,5-C6H2[CH2OCH2C(pz)3]4-
[Mn(CO)3]4}4ꢂ cation is situated on an inversion center.
The asymmetric unit contains one-half of the cation,
two BF4ꢁ anions and one Et2O and three CH3CN
solvent molecules of crystallization. All non-hydrogen
atoms were refined with anisotropic displacement para-
meters; hydrogen atoms were placed in geometrically
idealized positions and refined as riding atoms.
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/
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¨
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Crystallographic data for the structural analysis has
been deposited with the Cambridge Crystallographic
Centre, CCDC # 166559 for compound 1, CCDC #
191610 for compound 2, CCDC # 191611 for com-
pound 3 and CCDC # 175724 for compound 4. Copies
of this information may be obtained free of charge from
The Director, CCDC, 12 Union Road, Cambridge CB2
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1EZ, UK (Fax: ꢂ44-1223-336033; e-mail: deposit@
ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
/
[6] Strong hydrogen bonds include interactions of the type OÃ
/
HÁ Á ÁO,
NÃ
/
HÁ Á ÁO, OÃ
/
HÁ Á ÁN and NÃ
/
HÁ Á ÁN. See for example: ref [2b]; (a)
M.T. Allen, A.D. Burrows, M.F. Mahon, J. Chem. Soc. Dalton
Trans. (1999) 215; (b) U. Ziener, E. Breuning, J.-M. Lehn, E.
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Acknowledgements
We thank the National Science Foundation (CHE-
0110493) for support. The Bruker CCD Single Crystal
Diffractometer was purchased using funds provided by
the NSF Instrumentation for Materials Research Pro-
gram through Grant DMR:9975623.
[7] Weak hydrogen bonds (XÃ
atoms; we discuss here only CÃ
bond (YꢀO, F). See for example: (a) M.J. Calhorda, Chem.
/
HÁ Á ÁY) involve less electronegative
/
HÁ Á ÁY type of weak hydrogen
/
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Boese, H.L. Smith, M.M. Haley, Chem. Commun. (1997) 2403.
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