Electrochemical synthesis and structural characterization of silver(I) complexes of N-2-pyridyl sulfonamide ligands with different nuclearity: Influence of the steric hindrance at the pyridine ring and the sulfonamide group on the structure of the complexes

Article abstract of DOI:10.1021/ic0490268

A new series of silver complexes, [AgL], of the anionic forms of potentially bidentate N-2-pyridyl sulfonamide ligands [N-(3-methyl-2-pyridyl)-p- toluenenesulfonamide (HTs3mepy), N-(3-methyl-2-pyridyl)mesitylenesulfonamide (HMs3mepy), N-(4-methyl-2-pyridyl)-p-toluenesulfonamide (HTs4mepy), and N-(6-methyl-2-pyridyl)mesitylenesulfonamide (HMs6mepy)] have been prepared by an electrochemical procedure. In addition, heteroleptic complexes of composition [AgLL′] (L′ = 1,10-phenanthroline and 2,2′-bipyridine) were obtained when the coligand L′ was added to the electrolytic phase. The complexes were characterized by microanalysis, IR and ¹H NMR spectroscopy, and LSI mass spectrometry. In the cases of the compounds [Ag(Ts3mepy)]_n (1), [Ag₄(Ms3mepy)₄] (2a), [Ag(Ms3mepy)]_n (2b), [Ag₄(Ms6mepy)₄] (3a), [Ag₂(Ms6mepy)₂]_n (3b), [Ag₂(Ms3mepy) ₂(phen)₂] (5), [Ag₂(Ms6mepy)₂phen] (7), and [Ag₂(Ts4mepy)₂(bipy)₂] (8), characterization was also carried out by single-crystal X-ray diffraction. Compounds 1 and 2b present a polymer structure formed by an {AgN₂} digonal core. Compounds 2a and 3a are tetranuclear and also have a distorted {AgN₂} digonal core. Compound 3b is based on binuclear distorted {AgN₂} digonal units joined by an intermolecular sulfonyl oxygen atom to produce a stairlike polymer structure. The heteroleptic complexes 5 and 8 are dimeric with a distorted {AgN₄} tetrahedral geometry, while compound 7 shows two different geometries around the metal, distorted {AgN ₂} digonal and {AgN₄} tetrahedral. The supramolecular structures of all species are organized by π,π-stacking, C-H...π, or C-H...O interactions.

Full text of DOI:10.1021/ic0490268

Inorg. Chem. 2005, 44, 336−351
Electrochemical Synthesis and Structural Characterization of Silver(I)
Complexes of N-2-Pyridyl Sulfonamide Ligands with Different
Nuclearity: Influence of the Steric Hindrance at the Pyridine Ring and
the Sulfonamide Group on the Structure of the Complexes§
Inmaculada Beloso,† Jesu´s Castro,*,† Jose´ A. Garc´ıa-Va´zquez,‡ Paulo Pe´rez-Lourido,†
Jaime Romero,‡ and Antonio Sousa‡
Departamento de Qu´ımica Inorga´nica, Campus de As Lagoas, Marcosende, Edif. de Ciencias
Experimentais, UniVersidade de Vigo, 36200 PonteVedra, Spain, and Departamento de Qu´ımica
Inorga´nica, Campus Sur, UniVersidade de Santiago de Compostela, 15782 A Corun˜a, Spain
Received July 21, 2004
A new series of silver complexes, [AgL], of the anionic forms of potentially bidentate N-2-pyridyl sulfonamide ligands
[N-(3-methyl-2-pyridyl)-p-toluenenesulfonamide (HTs3mepy), N-(3-methyl-2-pyridyl)mesitylenesulfonamide (HMs3mepy),
N-(4-methyl-2-pyridyl)-p-toluenesulfonamide (HTs4mepy), and N-(6-methyl-2-pyridyl)mesitylenesulfonamide (HMs6mepy)]
have been prepared by an electrochemical procedure. In addition, heteroleptic complexes of composition [AgLL
′]
(L′ ) 1,10-phenanthroline and 2,2 -bipyridine) were obtained when the coligand L was added to the electrolytic
′
′
phase. The complexes were characterized by microanalysis, IR and 1H NMR spectroscopy, and LSI mass
spectrometry. In the cases of the compounds [Ag(Ts3mepy)]n (1), [Ag4(Ms3mepy)4] (2a), [Ag(Ms3mepy)]n (2b),
[Ag4(Ms6mepy)4] (3a), [Ag2(Ms6mepy)2]n (3b), [Ag2(Ms3mepy)2(phen)2] (5), [Ag2(Ms6mepy)2phen] (7), and [Ag2-
(Ts4mepy)2(bipy)2] (8), characterization was also carried out by single-crystal X-ray diffraction. Compounds 1 and
2b present a polymer structure formed by an
also have a distorted AgN2 digonal core. Compound 3b is based on binuclear distorted
joined by an intermolecular sulfonyl oxygen atom to produce a stairlike polymer structure. The heteroleptic complexes
5 and 8 are dimeric with a distorted AgN4 tetrahedral geometry, while compound 7 shows two different geometries
around the metal, distorted AgN2 digonal and AgN4 tetrahedral. The supramolecular structures of all species
are organized by -stacking, C ‚‚‚π, or C ‚‚‚O interactions.
{AgN2
}
digonal core. Compounds 2a and 3a are tetranuclear and
{
}
{
AgN2 digonal units
}
{
}
{
}
{
}
π
,
π
−H
−H
Chart 1
Introduction
The chemistry of metal complexes with pyridine-func-
tionalized amide ligands (Chart 1) has received a great deal
of attention,1-4 which is due, in part, to the fact that such
complexes can be made relatively easily. Furthermore,
variation of the substituents in these ligands is facile. This
latter feature provides the possibility of tailoring the bite
angle and degree of steric hindrance present in the ligand,
and in addition, it is believed that the presence of bulky
substituents on these ligands can stabilize the metal com-
plexes. A particular class of ligands of this type is the
pyridine sulfonamide ligands. These ligands are very versatile
in terms of their coordination modes; they can act as anionic
monodentate systems via the nitrogen pyridine atom (I)5 or
* Author to whom correspondence should be addressed. E-mail: jesusc@
uvigo.es.
§ Dedicated to Professor J. R. Dilworth, on the occasion of his 60th
birthday.
† Universidade de Vigo.
‡ Universidade de Santiago de Compostela.
(1) Kempe, R. Eur. J. Inorg. Chem. 2003, 791-803 and references therein.
(2) Clerac, R.; Cotton, F. A.; Dunbar, K. R.; Murillo, C. A.; Pascual, I.;
Wang, X. Inorg. Chem. 1999, 38, 2655-2657.
(3) Raston, C. L.; Skelton, B. W.; Tolhurst, V. A.; White, A. H.
Polyhedron 1998, 17, 935-942.
(4) Engelhardt, L. M.; Gardiner, M. G.; Jones, C.; Junk, P. C.; Raston,
C. L.; White, A. H. J. Chem. Soc., Dalton Trans. 1996, 3053-3057.
(5) Cabaleiro, S.; Castro, J.; Garc´ıa-Va´zquez, J. A.; Romero, J.; Sousa,
A. Acta Crystallogr. 2000, C56, 293-295.
336 Inorganic Chemistry, Vol. 44, No. 2, 2005
10.1021/ic0490268 CCC: $30.25
© 2005 American Chemical Society
Published on Web 12/15/2004

Ag(I) Complexes of N-2-Pyridyl Sulfonamide Ligands
Chart 2
ligands of the type shown in Chart 3. The complexes were
prepared using an electrochemical procedure in which the
metal is the anode of a cell containing an acetonitrile solution
of differently substituted N-2-pyridyl sulfonamide ligands.
Results and Discussion
Synthesis and General Characterization. The homolep-
tic and some heteroleptic silver(I) sulfonamide complexes,
[AgL] and [AgLL′] (L′ ) phen or bipy), can be readily
prepared in good yield by the electrochemical method
described, which is a methodology similar to that reported
previously for related systems.5-10
Thus, the electrochemical oxidation of anodic silver in a
cell containing different substituted N-2-pyridyl sulfonamide
ligands (HL) in acetonitrile gave the complexes [AgL] in
good yields. The compounds were obtained as white crystal-
line light-sensitive solids by air concentration of the resulting
acetonitrile solution.
Chart 3
Coligands such as 1,10-phenanthroline or 2,2′-bipyridine
were added to the electrochemical cell with the intention of
incorporating them as coligands for silver coordination in
an attempt to decrease the nuclearity of the compounds. The
electrochemical oxidation of silver in a solution of the N-2-
pyridyl sulfonamide ligands (HL) and an equimolecular
amount of 1,10-phenanthroline in acetonitrile gave the
complexes [Ag2L2phen2] or [Ag2L2phen], showing that the
coligand had been incorporated into the complex. Attempts
to obtain crystals of complexes 4 and 6 that were suitable
for X-ray studies proved unsuccessful, but analytical and
spectroscopic data (vide infra) confirmed them to be silver-
(I) compounds with monoanionic sulfonamide and phenan-
throline ligands coordinated to the metal. Presumably these
compounds have structures similar to that of complex 5.
However, when the coligand 2,2′-bipyridine (bipy) was
added to the electrochemical cell, only in the case of the
N-(4-methyl-2-pyridyl)-p-toluenesulfonamide ligand was the
coligand incorporated into the metal coordination sphere. The
complex isolated in this case was [Ag2(Ts4mepy)2(bipy)2]
(8), as confirmed by X-ray diffraction. In all other cases,
the analytical data and the spectroscopic studies on the
resulting products did not show evidence for the incorpora-
tion of the additional coligand and the homoleptic compound
[AgL] was formed exclusively. This situation was confirmed
by X-ray studies on some of these products, 1, 2b, and 3b.
The compounds [Ag(Ms3mepy)]n (2b) and [Ag2(Ms6mepy)2]
(3b) prepared in this way are supramolecular isomers to
complexes 2a and 3a, respectively,14 with an identical
stoichiometry formed when the synthesis was carried out in
the absence of coligand (see Scheme 1).
amide nitrogen atom (II),6 act as chelates (III,7,8 IV9,10), or
act as bridges between two metal atoms (V,11 VI,12 VII12)
(Chart 2). In this way these complexes can have variable
nuclearities and great structural diversity.
This versatility, together with the plasticity of the silver-
(I) ion, which can adopt coordination numbers between 2
and 6 and various geometries ranging from linear through
to trigonal, tetrahedral, trigonal pyramidal, and octahedral,
can allow the construction of different architectures.13
Moreover, the presence in these ligands of different substit-
uents on the pyridine ring and on the sulfonic acid group
(Chart 3) allows the possibility of investigating whether the
position and number of substitutents has any influence on
the coordinative behavior of these ligands and, consequently,
on the structure of the corresponding amido silver complexes.
In addition, we were interested in incorporating coligands
such as 1,10-phenanthroline and 2,2′-bipyridine into the
coordination sphere of silver to determine whether its
presence could lead to novel structures.
Accordingly, we report here the synthesis of a series of a
homoleptic and heteroleptic neutral Ag(I) complexes with
(6) Beloso, I.; Castro, J.; Garc´ıa-Va´zquez, J. A.; Pe´rez-Lourido, P.;
Romero, J.; Sousa, A. Polyhedron 2003, 22, 1099-1111.
(7) Cabaleiro, S.; Castro, J.; Garc´ıa-Va´zquez, J. A.; Romero, J.; Sousa,
A. Polyhedron 2000, 19, 1607-1614.
(8) Cabaleiro, S.; Castro, J.; Va´zquez-Lo´pez, E.; Garc´ıa-Va´zquez, J. A.;
Romero, J.; Sousa, A. Polyhedron 1999, 18, 1669-1674.
(9) Beloso, I.; Castro, J.; Garc´ıa-Va´zquez, J. A.; Pe´rez-Lourido, P.;
Romero, J.; Sousa, A. Z. Anorg. Allg. Chem. 2003, 629, 275-284.
(10) Beloso, I.; Borra´s, J.; Castro, J.; Garc´ıa-Va´zquez, J. A.; Pe´rez-Lourido,
P.; Romero, J.; Sousa, A. Eur. J. Inorg. Chem. 2004, 635-645.
(11) Lee, C.-F.; Peng, S.-M. J. Chin. Chem. Soc. (Taipei) 1991, 38, 559-
564. Cheng, H.-Y.; Cheng, P.-H.; Lee, C.-F.; Peng, S.-M. Inorg. Chim.
Acta 1991, 181, 145-147.
The heteroleptic silver(I) sulfonamide compounds were
obtained as white crystalline light-sensitive solids by air
concentration of the resulting acetonitrile solutions. These
complexes were found to be more soluble than the homo-
leptic analogues in chloroform and a range of other chlori-
nated organic solvents.
(12) Cabaleiro, S.; Castro, J.; Va´zquez-Lo´pez, E.; Garc´ıa-Va´zquez, J. A.;
Romero, J.; Sousa, A. Inorg. Chim. Acta 1999, 294, 87-94.
(13) Klobystov, A. N.; Blake, A. J.; Chamness, N. R.; Lamenovskii, D.
A.; Majuga, A. G.; Zyk, N. V.; Schro¨der, M. Coord. Chem. ReV. 2001,
222, 155-192 and references therein.
(14) Moulton, B.; Zaworotko, M. J. Chem. ReV. 2001, 101, 1629-1658;
Abourahma, H., Moulton, B.; Kravtsov, V.; Zaworotko, M. J. J. Am.
Chem. Soc. 2002, 124, 9990-9991.
Inorganic Chemistry, Vol. 44, No. 2, 2005 337

Beloso et al.
Scheme 1
The electrochemical efficiency, defined as moles of metal
νas(SdO), and bands in the range 1140-1115 cm-1, which
are attributed to the νsym(SdO) vibrations. A band is also
observed at 2951-2931 cm-1, and this corresponds to
ν(CH3).
The room-temperature 1H NMR spectra of the complexes
do not contain the broad signal attributable to the -NH
hydrogen, which appears in the free ligand at δ 12.3-9.4
ppm. The absence of this signal in the complex is a result
of deprotonation of the ligand. The multiplet resonances in
the aromatic region, δ 8.1-6.3 ppm, and also the signals
corresponding to the methyl groups, δ 2.9-1.7 ppm, appear
slightly shifted with respect to those in the free ligand. This
is again due to the coordination of the ligand.
dissolved/Faraday of charge, was in all cases close to 1.0
mol‚F-1. This fact, together with the evolution of hydrogen
at the cathode, is compatible with the occurrence of the
following electrode reactions:
cathode: HL + e- f 1/2H2 + L-
anode: L- + Ag f [AgL] + e-
L- + Ag + L′ f [AgLL′] + e-
Here HL stands for the corresponding neutral sulfonamide
ligand and L′ ) phen or bipy.
The LSI mass spectra of the silver compounds show the
[AgL]+ ion with the appropriate isotope distribution at m/z
370 for the p-toluenesulfonamide derivative and m/z 398 for
the mesitylenesulfonamide complex. The peaks correspond-
ing to the free ligand at m/z 263 and 291, respectively, are
also observed.
Spectroscopic Properties of [AgL] Compounds. The IR
spectra of these complexes do not contain the band observed
in the ligand at 3248-3222 cm-1, which is attributed to
ν(N-H) stretching. This difference in the spectra indicates
that the ligand is in the anionic amidate form in the complex.
The spectra also show bands in the aromatic region that are
due to ν(CdN) (1608-1587 cm-1) and ν(CdC) (1580-1555
cm-1). These bands are shifted to lower frequencies with
respect the free ligand as a result of coordination through
the sulfonamide nitrogen atom. The spectra also show bands
in the region 1340-1325 cm-1, which are attributed to
Spectroscopic Properties of [Ag2L2phen2] and [Ag2-
L2phen] Compounds. The IR spectra of these complexes
do not contain the ν(N-H) band observed for the ligand.
The absence of this band is indicates that deprotonation of
the ligand has taken place. In addition to the bands described
338 Inorganic Chemistry, Vol. 44, No. 2, 2005

Ag(I) Complexes of N-2-Pyridyl Sulfonamide Ligands
above for the homoleptic compounds, the spectra of the
mixed complexes show bands at around 1510, 850, and 730
cm-1, which are typical for coordinated 1,10-phenanthro-
line.15,16
The room-temperature 1H NMR spectra of the complexes
do not contain the broad signal attributable to the -NH
proton. Once again, this is consistent with the deprotonation
of the ligand. The multiplet resonances, including those for
the 1,10-phenanthroline, appear in the aromatic region (δ
9.5-6.3 ppm). In the complexes the signals of the 1,10-
phenanthroline can be distinguished at low field from those
due to the aromatic sulfonamide ligand. In these cases the
signals attributable to the 2,9- and 3,8-protons of 1,10-
phenanthroline, between δ 9.5-9.1 and δ 8.2-7.7 ppm,
respectively, experience a small dowfield shift with respect
to the corresponding signals in the free ligand. This shift
provides evidence for the coordination of the 1,10-phenan-
throline molecule.17 Finally, the signals corresponding to the
methyl groups, δ 2.7-2.0 ppm, also appear slightly shifted
with respect to those in the free ligand, again due to
coordination of the ligand.
Figure 1. HTs4mepy. Selected bond distances (Å): N(11)-C(11) 1.351-
(3), N(11)-C(15) 1.365(3), N(11)-H(1) 0.89(2), N(12)-C(15) 1.341(3),
N(21)-C(21) 1.356(3), N(21)-C(25) 1.361(3), N(21)-H(2) 0.924(16),
N(22)-C(25) 1.348(3).
Scheme 2
The LSI mass spectra show the [AgLphen]+ ion, with the
appropriate isotope distribution, at m/z 551 for the p-
toluenesulfonamide mixed complex and m/z 578 for the
mesitylenesulfonamide complex. In all cases the peaks
corresponding to the free ligands are observed at m/z 263
and 291, respectively. For complexes 4 and 7 the peak
corresponding to the loss of 1,10-phenanthroline are also
observed at m/z 369 and 398, respectively.
Structure of HTs4mepy. A view of the structure of
HTs4mepy is shown in Figure 1, together with the atomic
numbering scheme.
Spectroscopic Properties of the [AgLbipy] Compound.
The IR spectrum of this complex shows bands and signals
similar to those described above for the homoleptic com-
plexes. Additional bands were also observed at 758 and 735
cm-1, and these are typical of coordinated 2,2′-bipyridine.16
The room-temperature 1H NMR spectrum of 8 shows signals
assignable to the hydrogens of 2,2′-bipyridine in addition to
the signals corresponding to the hydrogen atoms of the
deprotonated sulfonamide ligands. The downfield shift of
the signal attributable to the 3,3′-protons (δ 8.2 ppm) and
the upfield shift of the signal for the 6,6′-protons (δ 8.7 ppm)
provide evidence for the coordination of the 2,2′-bipyridine
ligand.18 The LSI mass spectrum shows a peak corresponding
to the [Ag(Ts4mepy)bipy]+ ion, with the appropriate isotope
distribution, at m/z 526. Peaks due to the loss of the 2,2′-
bipyridine coligand, [Ag(Ts4mepy)]+, at m/z 369 and the
free ligand at m/z 263 are also observed.
The molecular structure of this ligand is consistent with
an imide tautomer (I) (see Scheme 2) in which the two
independent molecules in the unit cell of HTs4mepy are
associated by intermolecular hydrogen bonds, through the
pyridine nitrogen atom with one of the sulfonyl oxygen atoms
and with the sulfonamide nitrogen atom of a neighboring
molecule (see figures in Supporting Information).
This situation is similar to that found in HTspy8 and
HMs6mepy9 but contrasts with the hydrogen network found
in HTs3mepy6 and HMs3mepy,10 where the presence of the
methyl group in position 3 of the pyridine ring precludes,
for steric reasons, the involvement of the Nsulfonamide atom in
the hydrogen bond.
Structures of Polymeric Compounds. Structures of [Ag-
(Ts3mepy)]n (1) and [Ag(Ms3mepy)]n (2b). The polymeric
structures of [Ag(Ts3mepy)]n (1) and [Ag(Ms3mepy)]n (2b),
together with the atomic numbering schemes adopted, are
shown in Figures 2 and 3, respectively. The packing along
the a axis is provided as Supporting Information.
The structures of these two compounds are similar in that
they have a crystallographically imposed symmetry in the
unit cell and can be described as one-dimensional helical
polymers with pitches of 6.2951(6) and 7.959(6) Å, respec-
tively. All Ag(I) ions adopt a regular digonal geometry
(AgN2) and are coordinated by two nitrogen atoms from
different sulfonamide ligands with a bond angle of 180° in
both cases. In this way the metals are bridged by two anionic
sulfonamide molecules that behave in a κ2(µ-N,N′) manner
Description of Structures. The ligand HTs4mepy and the
complexes 1, 2a,b, 3a,b, 5, 7, and 8 were studied by X-ray
diffraction. The crystal parameters, experimental details for
data collection, and bond distances and angles for all these
compounds are provided as Supporting Information.
(15) Schilt, A. A.; Taylor, R. C. J. Inorg. Nucl. Chem. 1959, 9, 211-221.
(16) Inskeep, R. G. J. Inorg. Nucl. Chem. 1962, 24, 763-776.
(17) Yamazaki, S. Polyhedron 1985, 4, 1915-1923. Annan, T. A.; Chadha,
R. K.; Tuck, D. G.; Watson, K. D. Can. J. Chem. 1987, 65, 2670-
2676.
(18) Castellano, S.; Gunther, H.; Ebersole, S. J. Phys. Chem. 1965, 69,
4166-4176. Mabrouk, H. E.; Tuck, D. G. J. Chem. Soc., Dalton Trans.
1988, 2539-2543.
Inorganic Chemistry, Vol. 44, No. 2, 2005 339

Beloso et al.
2.133(6) Å for 2b, respectively, are similar and are within
the normal range observed in other digonal Ag(I) complexes
of pyridine and/or sulfonamido ligands.19 However, these
distances are slightly shorter than those found in the dimeric
silver(I) complex with 2-pyridyl-p-toluenesulfonamide, where
the ligands also present a κ2(µ-N,N′) coordination but are in
a trans disposition (head to tail). This situation produces Ag-
Npy bond distances of 2.150(3) Å, which are shorter than
Ag-Namide, 2.164(3) Å, due to existence of short Ag‚‚‚Ag
[2.7392(10) Å] and Ag‚‚‚O [2.733(3) Å] interactions.11 This
Ag‚‚‚O interaction produces an Npy-Ag-Namide angle of
165.90(10)°, which is lower that the N-Ag-N angle of 180°
found in 1 and 2b.
Complexes 1 and 2b have a one-dimensional polymeric
structure along the a axis (Supporting Information) with
intermolecular π,π-stacking interactions between the pyridine
rings of two adjacent polymeric chains. These interactions
are of the offset or slipped-stacking type. The distances
between centroids are 3.6232(3) and 3.610(2) Å for 1 and
2b, respectively. Both planes are symmetry-imposed parallel,
and they are separated by 3.296(4) and 3.346(7) Å, respec-
tively, indicating a respective lateral displacement of 1.504-
(4) and 1.355(4) Å.
Figure 2. Structure of 1. Selected bond distances (Å) and angles (deg):
Ag(1)-N(2)a 2.141(3), Ag(1)-N(2) 2.141(3), Ag(1)-Ag(2)b 3.1476(3), Ag-
(1)-Ag(2) 3.1476(3), Ag(2)-N(1) 2.128(3), Ag(2)-N(1)c 2.128(3), N(2)a-
-
Ag(1)-N(2) 180.00(11), Ag(2)b-Ag(1)-Ag(2) 180.0, N(1)-Ag(2)-N(1)c
180.0(2), 106.46(12). Key: (a) -x, 1 - y, -z; (b) x - 1, y, z.
In both cases, nonclassical intermolecular H-bonds are
found. One of these occurs between a hydrogen atom of the
methyl group in the position para to the sulfonyl group
[C(13) for 1 and C(14) for 2b] and one of the oxygen atoms
of a sulfonyl group in a neighboring chain. The other
intermolecular C-H‚‚‚O interactions involve the hydrogen
atoms of the CH and methyl groups of the pyridine rings in
one chain and the oxygen atoms of neighboring chains
(Supporting Information). The association of each chain with
four other chains through π,π-stacking and C-H‚‚‚O inter-
actions leads to chains that are parallel to the a axis. In this
arrangement the sulfonyl groups of each chain intercalate
between two sulfonyl groups of two adjacent chains, and in
this way, π,π-stacking interactions are established.
Structure of Tetranuclear Compounds. Structure of
[Ag4(Ms3mepy)4] (2a). The molecular structure of [Ag4-
(Ms3mepy)4] (2a), a supramolecular structural isomer of 2b,
is shown in Figure 4, together with the atomic numbering
scheme adopted. For the sake of clarity, a view of the
coordination sphere of the metals is represented in Figure
4b.
Figure 3. Structure of 2b. Selected bond distances (Å) and angles (deg):
Ag(1)-N(2)a 2.133(6), Ag(1)-N(2) 2.133(6), Ag(1)-Ag(2) 3.980(3), Ag-
(2)-N(1)b 2.125(8), Ag(2)-N(1) 2.125(8), N(2)a-Ag(1)-N(2) 180.0, N(1)b-
Ag(2)-N(1) 180.0(4). Key: (a) 1 - x, 1 - y, -z; (b) -x, 1 - y, -z.
-
with the sulfonyl oxygen atoms not involved in the coordina-
tion. The distances between the Ag atoms and the nearest O
of the sulfonyl groups are 2.898(3) and 2.944(3) Å for 1
and 2.900(6) and 2.992(6) Å for 2b. The sulfonamide ligands
dispose themselves in a “head to head” and “tail to tail”
fashion, meaning that the silver atoms can be classified into
two different alternate groups according to their coordination
environment; one sort of Ag(I) is coordinated by two pyridine
nitrogen atoms, N(1)-Ag(1)-N(1′), while the other group
is coordinated by two sulfonamide nitrogen atoms, N(2)-
Ag(2)-N(2′). The distance between silver atoms in com-
pound 1, 3.1476(3) Å, is shorter than in 2b, 3.980(3) Å, but
both are too long for the existence of any Ag‚‚‚Ag interac-
tion.
The structure is formed by discrete molecules and consists
of a tetranuclear array of silver atoms, which are on the
vertex of an almost planar rhombic parallelogram [Ag-Ag-
Ag angles, 64.17(2), 64.68(2), 115.10(3), and 115.62(3)°,
rms ) 0.0644]. The overall pattern of metal-metal distances
is such that there are two shorter and two longer distances.
These distances, which are in the range 2.9803(9)-3.3033-
(19) Ahrens, B.; Friedrichs, S.; Herbst-Irmer, R.; Jones, P. C. Eur. J. Inorg.
Chem. 2000, 2017-2029. Kristiansson, O. Acta Crystallogr. 2000,
C56, 165-167. Engelhardt, L. M.; Jacobsen, G. E.; Patalinghug, W.
C.; Skelton, B. W.; Raston, C. L.; White, A. H. J. Chem. Soc., Dalton
Trans. 1991, 2859-2868. Blaschette, A.; Jones, P. G.; Hamman, T.;
Naveke, M.; Schomburg, D.; Cammenga, H. K.; Epple, M.; Steppuhn,
I. Z. Anorg. Allg. Chem. 1993, 619, 912-922.
In both compounds the Ag-Npy and Ag-Namide bond
lengths, 2.128(3) and 2.141(3) Å for 1 and 2.125(8) and
340 Inorganic Chemistry, Vol. 44, No. 2, 2005

Ag(I) Complexes of N-2-Pyridyl Sulfonamide Ligands
Figure 4. (a) Structure of 2a and (b) partial view of 2a. Selected bond distances (Å) and angles (deg): Ag(1)-Ag(2) 2.9932(9), Ag(2)-Ag(3) 3.3033(9),
Ag(3)-Ag(4) 2.9803(9), Ag(4)-Ag(1) 3.2736(9), Ag(1)-N(21) 2.117(6), Ag(1)-N(11) 2.146(6), Ag(2)-N(32) 2.097(5), Ag(2)-N(22) 2.107(6), Ag(3)-
N(41) 2.132(6), Ag(3)-N(31) 2.142(6), Ag(4)-N(42) 2.074(6), Ag(4)-N(12) 2.092(6), N(21)-Ag(1)-N(11) 175.5(3), N(32)-Ag(2)-N(22) 177.5(2),
N(41)-Ag(3)-N(31) 174.5(3), N(42)-Ag(4)-N(12) 179.1(2).
Table 1. Selected Bond Distances (Å) and Angles (deg)
compd
HTs3mepy
Namide-Cpy
Npy-Cpy
Ag‚‚‚O
Ag‚‚‚Ag
N-Ag-Ndigonal
ref
1.346(4)
1.416(5)
1.362(5)
1.347(5)
6
[Ag(Ts3mepy)]n (1)
2.898(3) [Ag(1)-O(1)]
2.944(3) [Ag(2)-O(2)]
this work
3.1476(3)
180
HMs3mepy
1.326(2)
1.359(2)
10
[Ag(Ms3mepy)]n (2b)
1.407(10)
1.354(10)
2.900(6) [Ag(1)-O(1)]
2.992(6) [Ag(2)-O(1)]
2.835(5) [Ag(1)-O(11)]
2.855(5) [Ag(2)-O(31)]
2.749(5) [Ag(3)-O(32)]
2.973(5) [Ag(4)-O(12)]
3.084(4) [Ag-O(2)]
this work
3.980(3)
180
175.5(3)
177.5(2)
174.5(3)
179.1(2)
Namide-Ag-Npy Td
[Ag4(Ms3mepy)4] (2a)
1.401(8)
1.376(8)
1.425(8)
1.402(8)
1.416(7)
1.347(2)
1.381(6)
1.374(5)
1.349(8)
1.373(9)
1.338(8)
1.372(8)
1.340(6)
1.367(2)
1.350(6)
1.358(5)
2.9932(9) [Ag(1)-Ag(2)]
3.3033(9) [Ag(2)-Ag(3)]
3.2736(9) [Ag(1)-Ag(4)]
3.3549(9) [Ag(1)-Ag(3)]
3.4221(12)
this work
[Ag2(Ms3mepy)2(phen)2](5)
HMs6mepy
[Ag4(Ms6mepy)4] (3a)
[Ag2(Ms6mepy)2]n (3b)
this work
9
this work
this work
2.730(4) [Ag-O(2)]
2.8847(6)
2.7374(8)
171.52(16)
157.46(13)
2.565(3) [Ag-O(2)] inter
2.730(3) [Ag-O(1)] intra
2.884(11) [Ag(1)-O(11)]
[Ag2(Ms6mepy)2(phen)] (7)
HTs4mepy
1.350(19)
1.341(3)
1.348(3)
1.382(4)
1.393(18)
1.365(3)
1.361(3)
1.355(4)
2.789(2)
178.6(7)
[Ag2(Ts4mepy)2(bipy)2] (8)
3.097(2) [Ag(1)-O(11)]
2.9166(5)
Namide-Ag-Npy Td
this work
(9) Å, are too long to consider the existence of a significant
silver-silver interaction.
two different ligands, while the other pair, Ag(2) and Ag-
(4), is coordinated by two sulfonamide nitrogen atoms, also
from two different ligands. In this way, the ligands are
coordinated in head to head and tail to tail forms.
The silver atoms are coordinated by four anionic sulfon-
amide molecules that behave in a η2(κ-N,N′) manner. The
distances between the silver centers and the nearest oxygen
atoms of the sulfonyl groups vary from 2.749(5) to 2.973-
(5) Å. Consequently, if the silver-silver and silver-oxygen
interactions are ignored, the coordination geometry around
each silver atom can be described as almost linear (AgN2),
with the N-Ag-N angles in the range 174.5(2)-179.1(2)°.
It appears that a correlation exists between the Ag‚‚‚O
distances and the value of the N-Ag-N angle. The
difference in the N-Ag-N angle with respect to the ideal
value of 180° increases as the Ag‚‚‚O distance decreases
(Table 1), i.e., as the interaction becomes stronger. On the
assumption that the four metal atoms show a AgN2 digonal
coordination, the silver centers can be divided into two
different pairs according to the nature of the nitrogen atoms
coordinated to them. One pair, containing atoms Ag(1) and
Ag(3), is coordinated by two pyridine nitrogen atoms from
The lengths of the Ag-Npy bonds are in the range 2.117-
(6)-2.146(6) Å, with an average value of 2.132(6) Å. These
are similar to the corresponding bond lengths found in
complexes 1 and 2b but are longer than the Ag-NMs bond,
2.074(6)-2.107(6) Å [average value of 2.091(3) Å].
The pyridine rings are almost perpendicular to the plane
described by the four silver atoms, with an average dihedral
angle of 87.5(1)°. This disposition is stabilized by a weak
π,π-stacking interaction between these pyridine rings; the
distances between centroids are 3.8686(2) and 3.6282(3) Å,
and the average value for the dihedral angle between rings
is 6.1(3)°. Intermolecular C-H‚‚‚O interactions are also
present in 2a. Each tetramer interacts with two neighboring
units, using one hydrogen atom from a methyl group in the
ortho position of the mesityl group and one hydrogen atom
from the adjacent CH group with one oxygen atom of the
Inorganic Chemistry, Vol. 44, No. 2, 2005 341

Beloso et al.
Figure 5. (a) Structure of 3a and (b) partial view for 3a. Selected bond distances (Å) and angles (deg): Ag-N(2) 2.144(4), Ag-N(1)a 2.147(4), Ag-Aga
2.8834(7), N(2)-Ag-N(1)a 171.52(16), Aga-Ag-Agb 89.187(4). Key: (a) 3/2 - y, x + 1/2, 3/2 - z; (b) y - 1/2, 3/2 - x, 3/2 - z.
other tetrameric unit. The other interaction is established
between one hydrogen atom of CH(py) in the para position
to the pyridine nitrogen atom and an oxygen atom from
another tetranuclear molecule (Supporting Information).
Structure of [Ag4(Ms6mepy)4] (3a). A view of the
molecular structure of 3a with the atom labeling scheme is
shown in Figure 5. The structure consists of discrete
molecules that have a crystallographically imposed symmetry
in the unit cell.
As in 2a, compound 3a has an additional weak interaction
with the oxygen atom of the sulfonyl group. Once again,
this interaction introduces modifications in the N-Ag-N
angle and the Ag‚‚‚Ag distance. The Ag‚‚‚O distance [2.730-
(4) Å] is shorter than the Ag‚‚‚O average distance of 2.853-
(5) Å in 2a, which indicates that the Ag‚‚‚O interaction in
3a is stronger than that in complex 2a. As a consequence,
the N-Ag-N angle in 3a [171.49(16)°] is smaller than in
2a [174.5(2)-179.1(1)°].
Complex 3a has a tetranuclear structure different from that
described for 2a. The lattice is formed by discrete molecules
with a tetranuclear arrangement of silver atoms on the
vertexes of an almost perfect square parallelogram: Ag-
Ag-Ag angles are close to 90° (89.19°). This parallelogram
is less planar than the one described for 2a (rms ) 0.1718).
The distance between contiguous silver atoms, 2.8834(7) Å,
is smaller than in compound 2a [2.9803(9)-3.3033(9) Å]
and also slightly shorter than the one in metallic silver (2.888
Å).20 However, the distance is still significantly less than
twice the van der Waals radius for silver (3.44 Å).21
Consequently, it can be postulated that some intramolecular
Ag‚‚‚Ag interaction exists.
The silver atoms are also bridged by four anionic sul-
fonamide molecules that behave in a η2(κ-N,N′) manner. In
this case, the environment around each silver atom is the
same, which contrasts to the situation found in complex 2a.
Each silver atom in 3a is now coordinated by a pyridine
nitrogen atom and a sulfonamide nitrogen atom from
different ligands. In this way, each ligand spans the metal
centers in a head to tail arrangement. The coordination
geometry is best described as distorted AgN2 digonal, 171.52-
(16)°.
The values of the different Ag-N bond lengths are very
similar at 2.147(4) and 2.146(4) Å for Ag-Npy and Ag-
NMs, respectively. These values are similar to those found
for the polymeric complexes 1 and 2b described above, but
the Ag-NMs bond distances in 3a are slightly shorter than
those found in complex 2a.
The pyridine rings and the plane described by the four
silver atoms, Ag4, form a dihedral angle with an average
value 88.7(1)°, i.e., almost perpendicular. As in the case of
2a, this disposition is stabilized by a strong π,π-stacking
interaction between these pyridine rings, with the average
value of distances between centroids being 3.5153(3) Å and
a dihedral angle between the rings of 2.7(2)°. In 3a a weak
intermolecular C-H‚‚‚π interaction [C(6)-H‚‚‚π, 3.500(4)
Å, C-H‚‚‚π 139.4°] exists between one hydrogen atom of
the methyl group of the pyridine ring and the π-cloud of
one of the pyridine rings of other tetranuclear molecule
(Supporting Information).
Structure of Dinuclear Compounds. Homoleptic Com-
plexes: Structure of [Ag2(Ms6mepy)2]n (3b). The product
obtained in the synthesis of the Ag(I) complex with N-(6-
methyl-2-pyridyl)mesitylenesulfonamide (HMs6mepy) and
2,2′-bipyridine was found to be [Ag2(Ms6mepy)2]n (3b), a
(20) Wells, A. F. Structural Inorganic Chemistry, 4th ed.; Oxford University
Press: London, 1975; p 1015.
(21) Bondi, A. J. Phys. Chem. 1964, 68, 441-451.
342 Inorganic Chemistry, Vol. 44, No. 2, 2005

Ag(I) Complexes of N-2-Pyridyl Sulfonamide Ligands
Figure 6. (a) Structure of 3b and (b) partial view of 3b. Selected bond distances (Å) and angles (deg): Ag-N(1) 2.188(4), Ag-N(2)a 2.187(4), Ag-Aga
2.7374(8), N(2)a-Ag-N(1) 157.46(13). Key: (a) 1/2 - x, 3/2 - y, 1 - z.
supramolecular structural isomer to 3a. The bipy coligand
was not incorporated into the coordination sphere of the
metal.
The molecular structure of this complex, along with the
atom numbering scheme, is shown in Figure 6.
The complex presents a dimeric structure that has a
crystallographically imposed symmetry in the unit cell. The
dimer units contain two anionic ligands that act as bidentate
bridges through the two nitrogen atoms κ2(µ-N,N′) in a head
to tail disposition. The coordination of the sulfonamide
molecules generates an eight-membered Ag2N4C2 ring analo-
gous to others described in the literature.22
In addition, the dimer units are intermolecularly joined
across the b axis by a sulfonyl oxygen atom bonded to a
silver atom of a neighboring molecule (Figure 7). The Ag‚
‚‚O(2′) (′: x, y - 1, z) bond distance, 2.565(3) Å, is 0.68 Å
Figure 7. Polymeric structure of 3b.
(21%) shorter than twice the van der Waals radius (3.24 Å)21
the N4C2 plane (rms ) 0.0142). This fact, along with the
presence of the weak intramolecular Ag‚‚‚O [2.730(3) Å]
interactions, produces an N-Ag-N angle of 157.46(13)°,
which is the lowest of all the complexes studied here. In
addition, the distance between the silver atoms is 2.7374(8)
Å, similar to that of the dimeric silver(I) complex with the
2-pyridyl-p-toluenesulfonamide ligand,11 and shorter than in
metallic silver, 2.888 Å, indicating a significant intermetallic
interaction.20
and similar to that found for other Ag(I) complexes with
sulfonyl oxygen intermolecular interactions.23 Thus, the
structure can be described as a stairlike polymer formed by
self-assembly of sulfonyl-O bridged dimers and is similar
to that found in other Ag(I) complexes with some amino
acids.24
As a consequence of this intermolecular interaction with
the oxygen sulfonyl atom, the core atoms in the eight-
membered ring Ag2N4C2 (rms ) 0.1538) are not coplanar.
The silver atoms are located 0.396(3) Å above and below
The geometry of the Ag(I) ion can therefore be considered
as highly distorted AgN2 digonal or, alternatively, as a
trigonal arrangement AgN2O if the intermolecular coordina-
tion with the oxygen atom is considered [N(1)-Ag-N(2′)
) 157.46(13)°, N(2′)-Ag-O(2′′) ) 117.70(11)°, and N(1)-
Ag-O(2′′) ) 84.83(12)°; ′, 1/2 - x, 3/2 - y, 1 - z; ′′, x, y
- 1, z]. The N-Ag-N angle is splayed wider compared to
the normal trigonal arrangement but deviates significantly
from a linear arrangement owing to the presence of the
coordinated oxygen atom. Therefore, in this complex the
ligand can be considered to act as a bridge between three
metal atoms (Scheme 3). As far as we are aware, this is the
(22) Fenske, D.; Baum, G.; Dehnicke, K. Z. Naturforsch. 1990, B45, 1273-
1278. Romero, M. A.; Salas, J. M.; Quiro´s, M.; Sa´nchez, M. P.;
Molina, J.; El-Bahraoui, J.; Faure, R. J. Mol. Struct. 1995, 354, 189-
195. Gagnon, C.; Hubert, J.; Rivest, R.; Beauchamp, A. L. Inorg.
Chem. 1977, 16, 2469-2473. Cotton, F. A.; Feng, X.; Matusz, M.;
Poli, R. J. Am. Chem. Soc. 1988, 110, 7077-7083. Olbrich, F.;
Zimmer, B.; Kastner, M.; von Schlabrendorff, C.; Vetter, G. Z.
Naturforsch. 1992, B47, 1571-1579.
(23) Moers, O.; Henschel, D.; Blaschette, A.; Jones, P. G. Z. Anorg. Allg.
Chem. 2000, 626, 2399-2408 and references therein. Blair, J. T.; Patel,
R. C.; Rogers, R. D.; Whitcomd, D. R. J. Imaging Sci. Technol. 1996,
40, 117-122. Baezinger, N. C.; Struss, A. W. Inorg. Chem. 1976,
15, 1807-1809.
(24) Nomiya, K.; Yokoyama, H. J. Chem. Soc., Dalton Trans. 2002, 2483-
2490.
Inorganic Chemistry, Vol. 44, No. 2, 2005 343

Beloso et al.
Scheme 3. Coordination Mode of N-2-Pyridyl-Sulfonamide Ligand in
[Ag2(Ms6mepy)2]n (3b)
between the silver atoms is 3.4221(12) Å, similar to twice
the van der Waals radius for silver (3.44 Å).21 This distance
is too long to consider the existence of a significant Ag‚‚‚
Ag interaction.
There are four different Ag-N bond distances. The Ag-
Npy bond length is 2.223(5) Å, which is shorter than that
found in the complex [Ag(py)4]+, 2.322 Å,25 and other AgN4
tetracoordinated Ag(I) complexes with ligands derived from
substituted pyridine (2.402-2.299 Å).26 The Ag-NMs bond
distance, 2.398(5) Å, is greater than those found in the
aforementioned complexes of silver(I), in which the silver
atom is diagonally coordinate, but is similar to the corre-
sponding value found in 7 (vide infra) for the bond involving
the amide nitrogen and four-coordinated silver atoms.
Finally, the Ag-N bonds to the phenanthroline ligands
are 2.394(5) and 2.409(5) Å, i.e., similar to those in other
AgN4 bidentate phenanthroline chelate complexes with
tetracoordinated Ag(I) (2.411-2.266 Å).27
The crystal packing of compound 5 is such that one of
the phenanthroline units in one molecule interacts with that
on a neighboring molecule through π,π-stacking interac-
tions28 [distances between centroids ) 3.5176(3) Å]. The
rings of the phenanthroline molecules that are involved in
such interactions are not totally eclipsed by one another,
meaning that an offset or slipped stacking situation is
observed as shown in Figure 9. This interaction is quite
surprising since it is produced between the benzene ring of
one phenanthroline moiety and the pyridine ring of another
phenanthroline. The third ring, also a pyridine ring, is not
involved in this interaction, meaning that there is a slippage
from one phenanthroline molecule to another of exactly the
size of a six-membered ring (benzene).
first example of this type of ligational mode for an N-2-
pyridyl sulfonamide ligand.
The Ag-N bond distances, 2.188(4) and 2.187(4) Å for
Ag-Npy and Ag-NMs, respectively, are longer than that
found in the digonal complex with 2-pyridyl-p-toluene-
sulfonamide ligand11 and those in other dicoordinated Ag(I)
complexes with pyridine and/or sulfonamido ligands.19 This
situation is as one would expect given the higher coordination
number.
In 3b an intermolecular C-H‚‚‚π interaction is observed
between a hydrogen atom of one methyl group in the ortho
position of the mesityl group and one phenyl ring of the
neighboring molecule. In addition, 3b presents a weak
intermolecular C-H‚‚‚O interaction involving the methyl
group of the pyridine ring and one oxygen atom. C-H‚‚‚O
and S-O‚‚‚Ag interactions connect the dimer units, produc-
ing a stairlike linear chain. These chains are connected to
one another through C-H‚‚‚π interactions (Supporting
Information).
Heteroleptic Phenanthroline Complexes. Structure of
[Ag2(Ms3mepy)2(phen)2] (5). The synthesis of heteroleptic
complexes with 1,10-phenanthroline allowed the crystal
structure of the Ag(I) mixed complex with the N-(3-methyl-
2-pyridyl)mesitylenesulfonamide ligand to be determined.
The molecular structure of [Ag2(Ms3mepy)2(phen)2] (5)
is shown in Figure 8, together with the atomic numbering
scheme adopted. The structure contains discrete molecules
that have a crystallographically imposed symmetry. For the
sake of clarity, a view of the coordination sphere of the
metals is represented in Figure 8b.
Other intermolecular interactions are also observed, and
these are nonclassical C-H‚‚‚O interactions between the
hydrogen atoms on the phenanthroline of one molecule and
the sulfonyl oxygen of another. The π,π-stacking interactions
and the nonclassical hydrogen bonds lead a macromolecular
network similar to a stairlike polymer (Supporting Informa-
tion).
The structure consists of a dimer in which each silver atom
has an AgN4 tetracoordinated environment and is bonded
by two anionic sulfonamide ligandssone through the sul-
fonamide nitrogen and the other through the pyridyl nitrogen
atom. The coordination sphere is completed by a bidentate
phenanthroline molecule. The dihedral angle between the
planes NMs-Ag-Npy and Nphen-Ag-Nphen is 84.7(2)°, which
is close to the ideal value of 90° for a tetrahedral geometry.
The restricted “bite” of the phenanthroline, N-Ag-N )
69.11(18)°, represents the one major deviation from the ideal
geometry. The shortest Ag‚‚‚O separation between the silver
atom and the nearest O atoms of the sulfonyl group is 3.084-
(4) Å, suggesting a weak interaction between them.
The anionic sulfonamide ligands behave as a bidentate
bridge, κ2(µ-N,N′), and are situated in a trans disposition. In
a similar way to 3b, the coordination of the sulfonamide
molecules generates an Ag2N4C2 eight-membered ring in a
“chair” disposition (see Figure 8b). This situation means that
the silver atoms are located 1.111(4) Å above and below
the C2N4 plane (rms ) 0.1551) (see Figure 8b). The distance
Structure of [Ag2(Ms6mepy)2phen] (7). The product
from the synthesis of the silver complex with N-(6-methyl-
2-pyridyl)mesitylenesulfonamide and 1,10-phenanthroline
gave crystals of [Ag2(Ms6mepy)2phen] (7) that were suitable
for X-ray studies. Unfortunately, the crystal data are of poor
quality and non-hydrogen atoms could not be refined with
(25) Nilsson, K.; Oskarsson, A. Acta Chem. Scand. 1982, A36, 605-610.
(26) Bowyer, P. K.; Porter, K. A.; Rae, A. D.; Wilis, A. C.; Wild, S. B.
Chem. Commun. 1998, 1153-1154. Horikoshi, R.; Mochida, T.; Maki,
N.; Yamada, S.; Moriyama, H. J. Chem. Soc., Dalton Trans. 2002,
28-33. Carluci, L.; Ciani, G.; Proserpio, D. M.; Rizzato, S. Cryst.
Eng. Commun. 2002, 4, 121-129. Hannon, M. J.; Bunce, S.; Clarke,
A. J.; Alcock, N. W. Angew. Chem., Int. Ed. 1999, 38, 1277-1278.
Mann, K. L. V.; Jeffery, J. C.; McCleverty, J. A.; Ward, M. D. J.
Chem. Soc., Dalton Trans. 1998, 3029-3036.
(27) Titze, C.; Kaim, W.; Zalis, S. Inorg. Chem. 1997, 36, 2505-2510.
Pallenberg, A. J.; Marschner, T. M.; Bamhart, D. M. Polyhedron 1997,
16, 2711-2719. Cardenas, D. J.; Collin, J. P.; Gavina, P.; Sauvage,
J. P.; De Cian, A.; Fischer, J.; Armaroli, N.; Flamigni, L.; Vicinelli,
V.; Balzani, V.; Clarke, A. J.; Alcock, N. W. J. Am. Chem. Soc. 1999,
121, 5481-5488. Schmittel, M.; Ganz, A.; Fenske, D.; Herderich, M.
J. Chem. Soc., Dalton Trans. 2000, 353-359.
(28) Janiak, C. J. Chem. Soc., Dalton Trans. 2001, 3885-3896.
344 Inorganic Chemistry, Vol. 44, No. 2, 2005

Ag(I) Complexes of N-2-Pyridyl Sulfonamide Ligands
Figure 8. (a) Structure of 5 and (b) partial view of 5. Selected bond distances (Å) and angles (deg): Ag-N(11)a 2.223(5), Ag-N(12) 2.398(5), Ag-N(21)
2.394(5), Ag-N(22) 2.409(5), Ag-Aga 3.4221(12), N(11)a-Ag-N(21) 143.27(17), N(11)a-Ag-N(12) 122.30(17), N(21)-Ag-N(12) 88.66(15), N(11)a-
Ag-N(22) 121.61(19), N(21)-Ag-N(22) 69.11(18), N(12)-Ag-N(22) 94.31(17). Key: (a) -x, 2 - y, -z.
-
Figure 9. Overlapping between phenanthroline rings of two neighboring molecules of 5.
Figure 10. (a) Structure of 7 and (b) partial view of 7. Selected bond distances (Å) and angles (deg): Ag(1)-N(21) 2.106(12), Ag(1)-N(12) 2.113(12),
Ag(1)-Ag(2) 2.789(2), Ag(2)-N(31) 2.324(9), Ag(2)-N(22) 2.377(12), Ag(2)-N(11) 2.385(12), Ag(2)-N(32) 2.426(8), N(21)-Ag(1)-N(12) 178.6(7),
N(31)-Ag(2)-N(22) 112.9(4), N(31)-Ag(2)-N(11) 118.3(4), N(22)-Ag(2)-N(11) 117.5(4), N(31)-Ag(2)-N(32) 69.5(5), N(22)-Ag(2)-N(32) 121.2-
(4), N(11)-Ag(2)-N(32) 108.7(4).
anisotropic displacement parameters. Nevertheless, the final
atom locations are shown in Figure 10a.
The structure is based on dimeric molecules, but two silver
atoms, two sulfonamide ligands, and only one phenanthroline
molecule form this time the dimer. This arrangement causes
the two metal atoms to exist in different environments. The
sulfonamide ligands again behave as bidentate bridges, κ2-
(µ-N,N′), in a trans disposition that generates a nonplanar
Inorganic Chemistry, Vol. 44, No. 2, 2005 345

Beloso et al.
Figure 11. (a) Crystal structure of 7 showing the π,π-stacking interactions as dotted lines and (b) overlap between phenanthroline rings of two neighboring
molecules of 7.
eight-membered Ag2N4C2 ring. However, in this case one
of the silver atoms, Ag(1) at a distance from the plane of
only 0.012(7) Å, is in the plane described by N4C2 (rms )
0.0617) and the other silver atom, Ag(2), is out of this plane
[by 1.251(8) Å] due the coordination of the phenanthroline
ligand (see Figure 10b). The Ag-Ag distance is 2.789(2)
Å. This is slightly longer than the distance found for complex
3b [2.7374(8) Å] but is markedly shorter than that described
above for complex 5 [3.4221(12) Å]. In any case, the distance
is slightly shorter than the 2.888 Å required for an Ag-Ag
metal bond and we can therefore we can envisage the
existence of a significant Ag‚‚‚Ag interaction.
The geometry of Ag(1) can best be described as slightly
distorted AgN2 digonal. One of the nitrogen atoms is a
pyridine nitrogen from one anionic sulfonamide ligand, and
the other is a sulfonamide nitrogen provided by another
ligand, N(21)-Ag(1)-N(12) ) 178.6(7)°. The other silver
atom, Ag(2), presents a distorted AgN4 tetrahedral geometry
and is bonded to one sulfonamide and one pyridine nitrogen
atom from the different sulfonamide ligands as well as a
bidentate phenanthroline molecule. In addition, each silver
atom in the dimer shows a weak intramolecular interaction
with an oxygen atom of the sulfonyl group, Ag(1)‚‚‚O(11)
) 2.884(11) and Ag(2)‚‚‚O(21) ) 2.911(10) Å. Once again,
the Ag(1)‚‚‚O(11) interaction gives rise to an N-Ag(1)-N
digonal angle of less than 180°.
of the phenanthroline interact. Moreover, the π,π-stacking
interaction is produced between the two pyridine rings of
the phenanthroline units. The planes are not exactly above
one another, but there is slippage of 1.775(9) Å. The distance
between centroids is 3.9926(5) Å and the distance between
planes is 3.576(9) Å. Hydrogen bonds were not found
between different units.
Heteroleptic Bipyridine Complex: Structure of [Ag2-
(Ts4mepy)2(bipy)2] (8). The molecular structure of the only
heteroleptic compound obtained with 2,2′-bipyridine as a
coligand, i.e., [Ag2(Ts4mepy)2(bipy)2] (8), is shown in Figure
12a together with the atomic numbering scheme adopted.
For the sake of clarity, a view of the coordination sphere of
the metals is represented in Figure 12b.
The structure of 8 is similar to that described for 5 and
consists of discrete dimeric molecules in which each silver
atom is tetracoordinated, bonding to two anionic sulfonamide
ligands that again behave as κ2(µ-N,N′) bidentate bridges in
a trans disposition. The coordination sphere is completed by
a bidentate bipyridine molecule, and the main source of
distortion of the tetrahedral polyhedron of the silver atom is
the small bite of the five-membered chelate rings, Nbipy
-
Ag-Nbipy angles of 67.33(8)°.
The coordination of the sulfonamide molecules generates
a puckered eight-membered Ag2N4C2 ring that is not
coplanar, with the silver atoms located 0.875(2) Å out of
the plane described by C2N4 (rms ) 0.0232) (see Figure 12b).
The distance between the silver atoms is 2.9166(5) Å, which
is longer than in 3b and 7 but shorter than in 5. The distance
between the silver and nearest oxygen atom, 3.097(2) Å, is
too great for this interaction to be considered as bond.
The dihedral angle formed by the bipyridine donor atoms
and the plane described by N(11)-Ag(1)-N(22) is 89.4-
(5)°, and with the plane N(21)-Ag(1)-N(12) this angle is
87.2(6)°. Both of these values are close to the theoretical
90° for a tetrahedral geometry.
All of the pyridine and sulfonamide Ag-N bond distances
are different, and as one would expect, these are shorter for
digonal Ag(1) [2.106(12) and 2.113(12) Å] than for tetra-
coordinated Ag(2) [2.385(12) and 2.377(12) Å] as a conse-
quence of the change in coordination number from 2 to 4.
Finally, in the phenanthroline ligand one Ag-N bond
length, 2.324(9) Å, is considerably shorter and the other
significantly longer, 2.426(8) Å, than expected. This indicates
a certain degree of distortion. The bond lengths are of the
same order as those found in 5.
The supramolecular arrangement found in 7 is different
from that described above for 5. In this case (Figure 11)
each phenanthroline molecule only interacts with one
phenanthroline on a neighboring molecule and this interaction
consists of π,π-stacking in such a way that only two rings
All of the Ag-N bond distances are different; the Ag-
py bond lengths are 2.284(3) Å, longer than in 5 but shorter
than in 7. the Ag-NTs distances are 2.277(3) Å, shorter than
in 5 and 7. Finally, the bipyridine nitrogen atoms are
asymmetrically coordinated with distances 2.439(3) and
N
346 Inorganic Chemistry, Vol. 44, No. 2, 2005

Ag(I) Complexes of N-2-Pyridyl Sulfonamide Ligands
Figure 12. (a) Structure of 8 and (b) partial view of 8. Selected bond distances (Å) and angles (deg): Ag(1)-N(12) 2.277(3), Ag(1)-N(11)a 2.284(3),
Ag(1)-N(21) 2.439(3), Ag(1)-N(22) 2.455(2), Ag(1)-Ag(1)a 2.9166(5), N(12)-Ag(1)-N(11)a 134.85(10), N(12)-Ag(1)-N(21) 119.32(9), N(11)a-Ag-
(1)-N(21) 102.87(9), N(12)-Ag(1)-N(22) 109.40(9), N(11)a-Ag(1)-N(22) 100.73(9), N(21)-Ag(1)-N(22) 67.33(8). Key: (a) 1 - x, 1 - y, 1 - z.
It was found that these sulfonamide ligands always act as
two-electron-pair donor κ2(µ-N,N′) bridges, with donation
occurring through the amido and pyridyl nitrogen atoms
regardless of the positions of the methyl groups. This
situation produces homoleptic compounds of different nucle-
arities, helical one-dimensional polymer, tetranuclear, and
dinuclear, with a digonal environment around the silver
atoms. In the heteroleptic systems only dinuclear complexes
with Ag(I) in a tetrahedral (or tetrahedral and digonal)
environment were found. It is also noteworthy that on using
2,2′-bipyridine as a coligand, only in the case of the silver
complex with N-(4-methyl-2-pyridyl)-p-toluenesulfonamide
was the bipy moiety incorporated into the complex. In the
other cases the complexes corresponding to the homoleptic
species [AgL] were obtained, albeit with different nucleari-
ties.
Figure 13. (a) Overlapping between bipyridine rings of two neighboring
molecules of 8.
The structure of the silver homoleptic complexes with
these ligands seems to depend on the position of the methyl
group in the pyridine ring and on the number and position
of the methyl groups in the benzene ring of the sulfonamide
group; see Scheme 4. For example, when the ligand used
2.455(2) Å. These bond lengths are typical for bidentate
bipyridine chelate Ag(I) compounds (2.467-2.26 Å).29
In complex 8, π,π-stacking interactions exist between the
bipyridine rings of different neighboring molecules. These
contains a methyl substitutent in position 3 of the pyridine
rings are displaced with respect to the ideal situation for
ring, the resulting compound, [Ag(Ts3mepy)]n (1), has a
“perfect facial alignment”. The centers of the rings are
polymeric structure. However, the substitution of the mesityl
separated by 3.8372(3) Å, but the planes are not exactly
group for the tosyl group produces two different supra-
parallel and are offset by about 3.53 Å with some degree of
slippage, as shown in Figure 13.
These π,π-stacking interactions, together with the CH-
(bipy)-O interactions, produce a macromolecular network
molecular isomeric compounds: [Ag(Ms3mepy)]n (2b), a
polymeric compound; [Ag4(Ms3mepy)4] (2a), a tetranuclear
compound. It seems that the increase in the steric hindrance
produced by the mesityl sulfonic group makes the stability
similar to a stairlike polymer (Supporting Information).
of both the polymer and the tetranuclear compound very
Conclusions
similar.
An increase in the steric effect produced by a methyl group
A number of new Ag(I) complexes with N-pyridyl
in position 6 as opposed to 3 on the pyridine ring, and also
the presence of three methyl groups in the benzene ring of
the sulfonamide group, lead to supramolecular isomeric
complexes [Ag4(Ms6mepy)4] (3a) and [Ag2(Ms6mepy)2]n
(3b). The first complex has a tetranuclear structure, but 3b
sulfonamide ligands have been prepared and characterized.
(29) Constable, E. C.; Edwards, A. J.; Haire, G. R.; Hannon, M. J.; Raithby,
P. R. Polyhedron 1998, 17, 243-253. Baum, G.; Constable, E. C.;
Fenske, D.; Housecroft, C. E.; Kulke, T. Chem. Commun. 1998, 2659-
2660.
Inorganic Chemistry, Vol. 44, No. 2, 2005 347

Beloso et al.
1
H, 5.3; N, 10.5; S, 11.8. H NMR (CDCl3; δ, ppm): 2.29 [s, 3H,
CH3(tolyl)]; 2.36 [s, 3H, CH3(py)]; 6.61 (d, 1H, py); 7.20 (s, 1H,
py); 7.23 (d, 2H, tolyl); 7.79 (d, 2H, tolyl); 8.11 (d, 1H, py); 11.8
(br, 1H, NH). IR (KBr, cm-1): 3228 (m), 2920 (w), 1612 (s), 1513
(s), 1392 (s), 1147 (s). EI MS: m/z: 262 (100%, M+).
can be considered as a dimeric compound. Once again, it
appears that the steric hindrance is not sufficiently great to
make the stability of the two compounds significantly
different.
The presence of an additional ligand typically reduces the
nuclearity of the complexes. For this reason the heteroleptic
complexes are only dimeric. However, the steric hindrance
of the sulfonamide ligand plays some role in this respect. In
the case of the heteroleptic phenanthroline compounds, the
complexes [Ag2(Ms3mepy)2(phen)2] (5) and [Ag2(Ms6mepy)2-
(phen)] (7) are both dimers. However, in the case of 7 the
greater hindrance produced by the methyl group in position
6 of the pyridine ring precludes the incorporation of a second
phenanthroline molecule. In addition, the structural deter-
minations reveal that the sulfonyl groups are canted with
respect to the adjacent N-Ag-N plane in such a way that
the oxygen atoms can form weak intramolecular interactions
with the silver atoms. The strength of this interaction is
reflected in the fact that the N-Ag-N angles are less obtuse
and the Ag‚‚‚Ag distances generally shorter in the complexes
in which silver is digonally coordinated (Table 1).
In the case of complex 3b, adjacent dimer units are linked
to give a 1-D network by linkages between the silver(I) atoms
of a dimer unit and the oxygen atom of the sulfonyl group
of the neighboring dimer. Therefore, each ligand acts as a
bridge between three metal atoms (Scheme 3). This is a new
form of coordination for pyridine-functionalized amido
ligands of the type represented in Chart 2.
Data for the Other Ligands. HMs6mepy. Anal. Calcd for
C15N2H18O2S: C, 62.1; H, 6.2; N, 9.6; S, 11.0. Found: C, 61.3; H,
6.4; N, 9.5; S, 10.9. 1H NMR (CDCl3; δ, ppm): 2.37 (s), 3H, CH3-
(py); 2.24 (s) 3H, CH3(p-tolyl); 2.69 (s) 6H, CH3(o-tolyl); 6.55 (d),
1H, py; 6.74 (d) 1H, py; 6.88 (s), 2H, tolyl; 7.37 (d) 1H, py; 12.33
(b) 1H, NH. IR (KBr, cm-1): 3236 (w), 2931 (w), 1616 (vs), 1533
(m), 1362 (vs), 1136 (vs). EI MS: m/z 291 (4%, M+), 108 (13%,
M+ - {O2S-mesityl}).
HMs3mepy. Anal. Calcd for C15N2H18O2S: C, 62.1; H, 6.2; N,
1
9.6; S, 11.0. Found: C, 61.3; H, 6.0; N, 9.3; S, 11.2. H NMR
(CDCl3; δ, ppm): 2.15 (s), 3H, CH3(py); 2.25 (s) 3H, CH3(p-tolyl);
2.71 (s) 6H, CH3(o-tolyl); 6.47 (d), 1H, py; 6.89 (s), 2H, tolyl;
7.36 (d) 1H, py; 7.42 (d) 1H, py; 12.3 3 (b) 1H, NH. IR (KBr,
cm-1): 3222 (m), 2940 (w), 1595 (s), 1544 (s), 1338 (s), 1098 (s).
EI MS: m/z 291 (100%, M+), 108 (10%, M+ - {O2S-mesityl}).
HTs3mepy. Anal. Calcd for C13N2H14O2S: C, 59.5; H, 5.4; N,
1
10.7; S, 12.2. Found: C, 58.7; H, 5.7; N, 10.2; S, 11.8. H NMR
(CDCl3; δ, ppm): 2.15 (s), 3H, CH3 (py); 2.35 (d) 3H, CH3 (tolyl);
6.50 (d), 1H, py; 7.40 (d), 1H, py; 7.49 (d), 1H, py; 7.85 (d), 2H,
tolyl; 7.21 (d), 2H, tolyl; 12.14 (b) 1H, NH. IR (KBr, cm-1): 3248
(m), 2951 (w), 1594 (s), 1544 (s), 1342 (s), 1126 (s). EI MS: m/z
262 (8%, M+); 108 (20%, M+ - {O2S-tolyl}).
Electrochemical Synthesis. The electrochemical method used
in the synthesis of the silver complexes is similar to that described
previously.5-10 An acetonitrile solution (50 mL) of either the
sulfonamide ligand (HL) or a mixture of the sulfonamide and a
coligand (L′ ) phen or bipy), with a small amount of tetramethyl-
ammonium perchlorate (ca. 10 mg) as the supporting electrolyte,
was electrolyzed using a sacrificial silver anode and a platinum
cathode. All syntheses were carried out with the electrochemical
cell protected from direct light.
In all complexes the sulfonyl ligand is coordinated as an
anion in the amide form and the Namide-Cpy bond distances
in the complexes are greater than the corresponding distances
in the free ligands (Table 1).
Experimental Section
Direct current was supplied by a purpose-built dc power supply.
Applied voltages of 5-10 V allowed sufficient current flow for
smooth dissolution of the silver metal. The current was maintained
at 10 mA during 1.5 h. In all cases, hydrogen was evolved at the
cathode. These cells can be summarized as Ag(+)/CH3CN + HL +
L′/Pt(-), where L and L′ represent the corresponding sulfonamide
ligand and the coligand, respectively. After completion of the
electrolysis, the clear solutions were filtered to remove any particles
of metal and then left to concentrate protected from direct light.
This procedure yielded crystalline products. The solids were washed
with acetonitrile and diethyl ether and dried at room temperature.
[Ag(Ts3mepy)]n (1). Method A. Electrolysis of an acetonitrile
solution (50 mL) containing N-(3-methyl-2-pyridyl)-p-toluene-
sulfonamide (HTs3mepy) (0.150 g, 0.565 mmol) at 7 V and 10
mA for 1.5 h dissolved 67.6 mg of metal (Ef ) 1.12 mol‚F-1).
During the electrolysis hydrogen was evolved at the cathode. Air
concentration of the resulting solution yielded white crystals (0.18
g, 86%) of [Ag(Ts3mepy)]n (1) suitable for X-ray studies.
Method B. Electrochemical oxidation of a silver anode in an
acetonitrile solution (50 mL) containing N-(3-methyl-2-pyridyl)-
p-toluenesulfonamide (0.150 g, 0.572 mmol) and 2,2′-bipyridine
(0.089 g, 0.570 mmol), using a current of 10 mA (6 V) for 1.5 h,
resulted in the dissolution of 56.6 mg of metal (Ef ) 0.93 mol‚F-1).
Air concentration of the resulting solution yielded white crystals
(0.18 g, 86%) corresponding to the homoleptic [Ag(Ts3mepy)]
complex, with no evidence for the incorporation of bipy into the
complex. Crystals suitable for X-ray studies were confirmed to be
General Considerations. Silver (Ega Chemie) was used as plates
(ca. 2 × 2 cm). All other reagents, including acetonitrile, dichlo-
romethane, 2-amino-3-methylpyridine, 2-amino-4-methylpyridine,
2-amino-6-methylpyridine, p-toluenesulfonyl chloride, 2-mesitylene-
sulfonyl chloride, 1,10-phenanthroline monohydrate, and 2,2′-bi-
pyridine, were commercial products and were used as supplied.
Microanalysis was performed using a Carlo-Erba EA 1108
microanalyzer. IR spectra were recorded as KBr disks with a Bruker
Vector-22 spectrophotometer. The 1H NMR spectra were recorded
on a Bruker ARX-400 MHz instrument using CDCl3 as solvent;
chemical shifts were determined against TMS as internal standard.
EI and LSI mass spectra were recorded on a VG Autospec-M
Micromass instrument.
Preparation of the Ligands. Ligands were prepared by reaction
of the corresponding amine with the sulfonyl chloride in a 1:1 molar
ratio. Details are given for a representative example.
HTs4mepy. 2-Amino-4-methylpyridine (2.0 g, 18.4 mmol) and
p-toluenesulfonyl chloride (3.51 g, 18.4 mmol) were dissolved in
dichloromethane. To this solution was added dropwise an aqueous
solution of sodium carbonate (1.95 g, 18.4 mmol in 20 mL). The
reaction mixture was stirred overnight, and water (100 mL) was
added. The organic layer was dried over anhydrous magnesium
sulfate, the solvent was evaporated, and the crude product (an oil)
was treated with ethanol. The resulting white solid was isolated
by filtration and identified as HTs4mepy. Anal. Calcd for
C13H14N2O2S: C, 59.5; H, 5.4; N, 10.7; S, 12.2. Found: C, 59.2;
348 Inorganic Chemistry, Vol. 44, No. 2, 2005

Ag(I) Complexes of N-2-Pyridyl Sulfonamide Ligands
[Ag(Ts3mepy)]n (1). Anal. Calcd for C13H13AgN2O2S: C, 42.4;
N, 7.6; H, 3.6; S, 8.7. Found: C, 42.6; N, 7.5; H, 3.8; S, 8.6. IR
(KBr, cm-1): 2920 (m), 1587 (m), 1416 (s), 1268 (vs), 1132 (vs).
1H NMR (CDCl3; δ, ppm): 7.92-6.96 (m, 7H, aromat), 2.39 [s,
3H, p-Me(Ts)], 2.10 [s, 3H, Me(py)]. LSIMS (m/z): 370, [Ag-
(Ts3mepy)]+; 263, [Ts3mepy]+.
[Ag4(Ms3mepy)4] (2a). Electrochemical oxidation of a silver
anode in a solution of N-(3-methyl-2-pyridyl)mesitylenesulfonamide
(HMs3mepy) (0.165 g, 0.565 mmol) in acetonitrile (50 mL), at 6
V and 10 mA for 1.5 h, caused 60.4 mg of silver to be dissolved
(Ef ) 1.00 mol‚F-1). Hydrogen was evolved at the cathode during
the electrolysis process. Air concentration of the resulting solution
yielded white crystals (0.19 g, 84%) of [Ag4(Ms3mepy)4] (2a)
suitable for X-ray studies. Anal. Calcd for C15H17AgN2O2S: C,
45.4; N, 7.1; H, 4.3; S, 8.1. Found: C, 45.6; N, 7.1; H, 4.3; S, 8.1.
IR (cm-1): 2928 (m), 1587 (m), 1416 (s), 1274 (vs), 1120 (vs). 1H
NMR (CDCl3; δ, ppm): 8.42-6.63 (m, 5H), 2.60 [s, 6H, Me(Ms)],
2.39 [s, 3H, p-Me(Ms)], 2.54 [s, 3H, Me(py)]. LSIMS (m/z): 398,
[Ag(Ms3mepy)]+; 291, [Ms3mepy]+.
AgN4O2S: C, 54.7; N, 10.2; H, 3.8; S, 5.8. Found: C, 54.6; N,
9.9; H, 3.5; S, 5.7. IR (KBr, cm-1): 2924 (m), 1590 (s), 1509 (m),
1417 (s), 1256 (s), 1135 (s), 841 (s), 728 (m). 1H NMR (CDCl3; δ,
ppm): 9.52 (m, 2H, phen), 8.55 (m, 2H, phen), 8.25 (s, 2H, phen),
8.11 (m, 2H, phen) 8.02-6.96 (m, 7H, aromat), 2.53 [s, 3H, p-Me-
(Ts)], 2.33 [s, 3H, Me(py)]. LSIMS (m/z): 551, [Ag(Ts3mepy)-
phen]+; 370, [Ag(Ts3mepy)]+; 263, [Ts3mepy]+.
[Ag2(Ms3mepy)2(phen)2] (5). A similar experiment (10 mA, 9
V, 1.5 h) using N-(3-methyl-2-pyridyl)mesitylenesulfonamide
(HMs3mepy) (0.165 g, 0.565 mmol) and 1,10-phenanthroline (0.102
g, 0.565 mmol) dissolved 69.6 mg of silver from the anode (Ef )
1.15 mol‚F-1). Suitable crystals of [Ag2(Ms3mepy)2(phen)2] (5) for
X-ray studies were obtained by crystallization from acetonitrile.
Yield: 0.28 g (86%). Anal. Calcd for C27H25AgN4O2S: C, 56.2;
N, 9.7; H, 4.3; S, 5.5. Found: C, 55.7; N, 10.4; H, 4.1; S, 5.6. IR
(KBr, cm-1): 2927 (s), 1588 (s), 1507 (m), 1414 (s), 1265 (s),
1
1130 (vs), 844 (s), 731 (m). H NMR (CDCl3; δ, ppm): 9.15 dd,
8.21, 8.19, 7.72 (m, 8H, phen), 7.60-6.53 (m, 5H, aromat), 2.05
[s, 3H, p-Me(Ms)], 2.41 [s, 6H, Me(Ms)], 1.87 [s, 3H, Me(py)].
LSIMS (m/z): 578, [Ag(Ms3mepy)(phen)]+; 291, [Ms3mepy]+.
[Ag(Ts4mepy)(phen)] (6). A similar experiment (10 mA, 8V,
1.5 h) using N-(4-methyl-2-pyridyl)-p-toluenesulfonamide (HTs4-
mepy) (0.150 g, 0.565 mmol) and 1,10-phenanthroline (0.102 g,
0.565 mmol) dissolved 55.4 mg of silver from the anode (Ef )
0.91 mol‚F-1). Air concentration of the resulting solution yielded
a white crystalline product (0.22 g, 78%). Anal. Calcd for C25H21-
AgN4O2S: C, 54.7; N, 10.2; H, 3.8; S, 5.8. Found: C, 54.4; N,
10.3; H, 3.6; S, 5.6%. IR (KBr, cm-1): 2920 (s), 1611 (vs), 1513
[Ag(Ms3mepy)]n (2b). A similar experiment (10 mA, 9 V, 1.5
h) using N-(3-methyl-2-pyridyl)mesitylenesulfonamide (HMs3mepy)
(0.165 g, 0.568 mmol) and 2,2′-bipyridine (0.089 g, 0.570 mmol)
dissolved 58.7 mg of silver from the anode (Ef ) 0.97 mol‚F-1).
The solution was air concentrated to yield a white solid (0.18 g,
86%). Crystals suitable for X-ray studies were found to be [Ag-
(Ms3mepy)]n (2b), with no evidence for the incorporation of bipy
into the complex. Anal. Calcd for C15H17AgN2O2S: C, 45.4; N,
7.1; H, 4.3; S, 8.1. Found: C, 45.1; N, 7.0; H, 4.2; S, 7.9%. IR
1
(cm-1): 2928 (m), 1585 (m), 1415 (s), 1277 (vs), 1129 (vs). H
1
(m), 1393 (vs), 1271 (s), 1148 (vs), 881 (s), 734 (s). H NMR
NMR (CDCl3; δ, ppm): 7.66-6.63 (m, 5H, aromat), 2.60 [s, 6H,
Me(Ms)], 2.39 [s, 3H, p-Me(Ms)], 2.54 [s, 3H, Me(py)]. LSIMS
(m/z): 398 [Ag(Ms3mepy)]+; 291 [Ms3mepy]+.
(CDCl3; δ, ppm): 9.23 (m, 2H, phen), 8.35 (m, 2H, phen), 8.18-
6.57 (m, 11H, phen + aromat), 2.40 [s, 3H, p-Me(Ts)], 2.29 [s,
3H, Me(py)]. LSIMS (m/z): 551, [Ag(Ts4mepy)(phen)]+; 263,
[Ts4mepy]+.
[Ag4(Ms6mepy)4] (3a). A similar experiment (7 V, 10 mA, 1.5
h) with silver as the anode and N-(6-methyl-2-pyridyl)mesitylene-
sulfonamide (HMs6mepy) (0.165 g, 0.565 mmol) in acetonitrile
(50 mL) dissolved 62.2 mg of metal (Ef ) 1.03 mol‚F-1). Air
concentration of the resulting solution yielded crystals (0.20 g, 89%)
of [Ag4(Ms6mepy)4] (3a) suitable for X-ray studies. Anal. Calcd
for C15H17AgN2O2S: C, 45.4; N, 7.1; H, 4.3; S, 8.1. Found: C,
46.2; N, 6.9; H, 4.1; S, 8.2%. IR (KBr, cm-1): 2932 (m), 1600
[Ag2(Ms6mepy)2(phen)] (7). A similar experiment (10 mA, 6
V, 1.5 h) using N-(6-methyl-2-pyridyl)mesitylenesulfonamide
(HMs6mepy) (0.165 g, 0.565 mmol) and 1,10-phenanthroline (0.102
g, 0.565 mmol) dissolved 58.7 mg of silver from the anode (Ef )
0.97 mol‚F-1). Air concentration of the resulting solution yielded
a white crystalline product (0.24 g, 75%). Suitable crystals of [Ag2-
(Ms6mepy)2(phen)] (7) for X-ray studies were obtained. Anal. Calcd
for C42H42Ag2N6O4S2: C, 51.8; N, 8.6; H, 4.3; S, 6.6. Found: C,
51.4; N, 9.2; H, 4.1; S, 6.7%. IR (KBr, cm-1): 2931 (m), 1592
(m), 1510 (w), 1453 (vs), 1278 (m), 1124 (vs), 847 (s), 729 (m).
1H NMR (CDCl3; δ, ppm): 9.47 (m, 2H, phen), 8.21 (m, 2H, phen),
8.18 (s, 2H, phen), 7.68 (m, 2H, phen), 7.16-6.40 (m, 10H,
aromat.), 2.16 [s, 6H, p-Me(Ms)], 2.71 [s, 12H, Me(Ms)], 2.58 [s,
6H, Me(py)]. LSIMS (m/z): 578, [Ag(Ms6mepy)(phen)]+; 398,
[Ag(Ms6mepy)]+; 291, [Ms6mepy]+.
1
(m), 1456 (s), 1287 (s), 1126 (vs). H NMR (CDCl3; δ, ppm):
7.26-6.55 (m, 5H), 2.72 [s, 6H, Me(Ms)], 2.17 [s, 3H, p-Me(Ms)],
2.57 [s, 3H, Me(py)]. LSIMS (m/z): 398 [Ag(Ms6mepy)]+; 291
[Ms6mepy]+.
[Ag2(Ms6mepy)2]n (3b). A solution of N-(6-methyl-2-pyridyl)-
mesitylenesulfonamide (HMs6mepy) (0.165 g, 0.568 mmol) and
2,2′-bipyridine (0.089 g, 0.570 mmol) in acetonitrile (50 mL) was
electrolyzed at 5 V and 10 mA during 1.5 h, and 55.4 mg of silver
metal was dissolved from the anode (Ef ) 0.92 mol‚F-1). The
solution was air concentrated to yield a white solid (0.17 g, 81%).
Crystals suitable for X-ray studies were identified as [Ag2-
(Ms6mepy)2]n (3b). Anal. Calcd for C15H17AgN2O2S: C, 45.4; N,
7.1; H, 4.3; S, 8.1. Found: C, 45.2; N, 7.3; H, 4.1; S, 8.2. IR (KBr,
cm-1): 2932 (m), 1596 (m), 1455 (s), 1269 (s), 1118 (vs). 1H NMR
(CDCl3; δ, ppm): 7.26-6.55 (m, 5H), 2.72 [s, 6H, Me(Ms)], 2.17
[s, 3H, p-Me(Ms)], 2.57 [s, 3H, Me(py)]. LSIMS (m/z): 398, [Ag-
(Ms6mepy)]+; 291, [Ms6mepy]+.
[Ag(Ts3mepy)(phen)] (4). A similar experiment (10 mA, 6 V,
1.5 h) using N-(3-methyl-2-pyridyl)-p-toluenesulfonamide (HTs3-
mepy) (0.150 g, 0.565 mmol) and 1,10-phenanthroline (0.102 g,
0.565 mmol) dissolved 66.7 mg of silver from the anode (Ef )
1.10 mol‚F-1). Air concentration of the resulting solution yielded
a white crystalline product (0.25 g, 81%). Anal. Calcd for C25H21-
[Ag2(Ts4mepy)2(bipy)2] (8). Electrochemical oxidation of a
silver anode in a solution of N-(4-methyl-2-pyridyl)-p-toluene-
sulfonamide (HTs4mepy) (0.150 g, 0.565 mmol) and 2,2′-bipyridine
(0.089 g, 0.565 mmol) in acetonitrile (50 mL) using a current of
10 mA, 9 V, for 1.5 h resulted in the dissolution of 56.0 mg of
metal (Ef ) 0.92 mol‚F-1). Crystals obtained by crystallization from
acetonitrile were studied by X-ray diffraction and were found to
be [Ag(Ts4mepy)(bipy)]2 (8). Yield: 0.22 g (81%). Anal. Calcd
for C23H21AgN4O2S: C, 52.6; N, 10.7; H, 4.0; S, 6.1. Found: C,
54.3; N, 10.3; H, 4.2; S, 6.4. IR (KBr, cm-1): 2922 (w), 1610
1
(vs), 1394 (s), 1278 (vs), 1148 (s), 758 (m), 735 (s). H NMR
(CDCl3; δ, ppm): 8.66 (d, 2H, bipy), 8.27 (m, 2H, bipy), 8.06 (m,
2H, bipy), 7.80 (m, 2H, bipy), 7.68-6.47 (m, aromat), 2.31 [s, 3H,
p-Me(Ts)], 2.19 [s, 3H, Me(py)]. LSIMS (m/z): 526, [Ag-
(Ts4mepy)(bipy)]+; 370, [Ag(Ts4mepy)]+; 263, [Ts4mepy]+.
Inorganic Chemistry, Vol. 44, No. 2, 2005 349

Beloso et al.
Table 2. Crystal and Structure Refinement Data for X-ray Studies
[Ag(Ts3mepy)]n
[Ag(Ms3mepy)]n
[Ag4(Ms3mepy)4]
[Ag4(Ms6mepy)4]
HTs4mepy
(1)
(2b)
(2a)
(3a)
empirical formula
fw
C13H14N2O2S
262.32
C13H13AgN2O2S
369.18
C15H17AgN2O2S
397.24
C60H68Ag4N8O8S4
1588.94
C60H68Ag4N8O8S4
1588.94
wavelength (Å)
cryst system
space group
0.710 73
monoclinic
P21/n
a ) 10.8901(9)
b ) 15.5093(13)
c ) 15.8472(14)
R ) 90
â ) 102.689(2)
γ ) 90
2611.2(4)
8
1.335
0.243
1104
0.710 73
triclinic
P1h
0.710 73
triclinic
P1h
0.710 73
orthorhombic
Fdd2
0.710 73
tetragonal
I41/a
a ) 15.6997(13)
b ) 15.6997(13)
c ) 25.219(3)
R ) 90
â ) 90
γ ) 90
6216.0(11)
4
1.698
unit cell dimens (Å, deg)
a ) 6.2951(6)
b ) 8.2405(8)
c ) 13.7554(13)
R ) 95.041(2)
â ) 94.465(2)
γ ) 102.787(2)
689.68(11)
2
1.778
1.611
368
0.22 × 0.14 × 0.12
1.49-28.00
-6 e h e 8
-10 e k e 10
-18 e l e 13
4292
a ) 7.960(6)
b ) 8.294(6)
c ) 12.598(10)
R ) 97.131(15)
â ) 93.498(14)
γ ) 108.003(15)
780.5(10)
2
1.690
1.430
400
0.29 × 0.16 × 0.06
1.64-28.08
-10 e h e 9
-7 e k e 10
-16 e l e 16
4621
a ) 32.464(4)
b ) 58.645(7)
c ) 13.3568(14)
R ) 90
â ) 90
γ ) 90
V (Å3)
25429(5)
Z
16
1.660
1.404
12800
0.33 × 0.12 × 0.12
1.43-28.07
-42 e h e 42
-40 e k e 77
-17 e l e 17
35 385
D(calcd) (Mg/m3)
abs coeff (mm-1
F(000)
)
1.436
3200
cryst size (mm3)
0.33 × 0.22 × 0.15
0.14 × 0.14 × 0.06
1.53-28.03
-20 e h e 18
-14 e k e 20
-33 e l e 30
16 429
θ range for data collcn (deg) 1.86-28.03
index ranges
-14 e h e 13
-20 e k e 15
-19 e l e 20
13 925
reflns collcd
indep reflns
5785 [R(int) ) 0.0509] 2995 [R(int) ) 0.0233] 3241 [R(int) ) 0.0638] 14105 [R(int) ) 0.0861] 3684 [R(int) ) 0.1212]
completeness to θ (%)
max and min transm
data/restraints/params
GOF on F2
95.5 (θ ) 25.00°)
0.964 and 0.928
5785/1/337
94.7 (θ ) 25.00°)
0.824 and 0.732
2995/0/177
91.1 (θ ) 25.00°)
0.918 and 0.681
3241/0/197
99.3 (θ ) 26.00°)
0.845 and 0.629
14105/1/773
0.645
98.9 (θ ) 26.00°)
0.917 and 0.818
3684/0/195
0.806
0.955
0.917
0.730
final R indices [I > 2σ(I)]
R1 ) 0.0447
wR2 ) 0.0619
R1 ) 0.1905
wR2 ) 0.0774
R1 ) 0.0410
wR2 ) 0.0997
R1 ) 0.0543
wR2 ) 0.1038
R1 ) 0.0818
wR2 ) 0.1886
R1 ) 0.1219
wR2 ) 0.2056
R1 ) 0.0398
wR2 ) 0.0459
R1 ) 0.1413
wR2 ) 0.0609
-0.019(19)
R1 ) 0.0407
wR2 ) 0.0463
R1 ) 0.1991
wR2 ) 0.0642
10(10)
R indices (all data)
absolute struct param
largest diff peak and
0.168 and -0.203
1.959 and -0.561
1.728 and -2.632
0.323 and -0.478
0.455 and -0.439
hole (e‚Å-3
)
[Ag2(Ms6mepy)2]n
[Ag2(Ms3mepy)2(phen)2]
[Ag2(Ms6mepy)2phen]
[Ag2(Ts4mepy)2(bipy)2]
(3b)
(5)
(7)
(8)
empirical formula
fw
C15H17AgN2O2S
397.24
C27H25AgNO2S
577.44
C42H42Ag2N6O4S2
974.68
C23H21AgN4O2S
525.37
wavelength (Å)
cryst system
space group
0.710 73
monoclinic
C2/c
a ) 24.007(4)
b ) 6.9006(12)
c ) 21.052(4)
R ) 90
â ) 115.226(4)
γ ) 90
3155.0(10)
8
1.673
1.415
1600
0.23 × 0.08 × 0.06
1.88-28.06
-25 e h e 31
-8 e k e 9
-27 e l e 15
8432
0.710 73
triclinic
P1h
a ) 10.6773(12)
b ) 10.8816(11)
c ) 12.1176(12)
R ) 84.481(3)
â ) 88.170(3)
γ ) 62.599(2)
1244.0(2)
0.710 73
triclinic
P1h
a ) 10.3032(13)
b ) 13.0738(18)
c ) 17.166(3)
R ) 77.842(5)
â ) 75.228(4)
γ ) 89.953(13)
2182.3(6)
0.710 73
triclinic
P1h
unit cell dimens (Å, deg)
a ) 9.6451(10)
b ) 10.4805(10)
c ) 12.5890(13)
R ) 71.869(2)
â ) 76.127(2)
γ ) 66.900(2)
1102.29(19)
2
1.583
1.037
532
0.30 × 0.25 × 0.20
1.72-28.04
-12 e h e 12
-13 e k e 13
-15 e l e 16
6919
V (Å3)
Z
2
2
D(calcd) (Mg/m3)
1.542
0.926
588
0.16 × 0.15 × 0.07
1.69-27.99
-13 e h e 13
-14 e k e 13
-15 e l e 9
7048
1.483
1.039
988
0.11 × 0.07 × 0.04
1.60-28.01
-5 e h e 4
-17 e k e 13
-22 e l e 20
6438
abs coeff (mm-1
F(000)
)
cryst size (mm3)
θ range for data collcn (deg)
index ranges
reflns collcd
indep reflns
3496 [R(int) ) 0.0622]
94.9 (θ ) 26.00°)
0.919 and 0.873
3496/0/194
0.800
4879 [R(int) ) 0.0573]
90.2 (θ ) 24.00°)
0.937 and 0.862
4879/0/320
0.703
4191 [R(int) ) 0.0654]
44.3 (θ ) 26.00°)
0.959 and 0.916
4191/0/251
0.854
4822 [R(int) ) 0.0442]
95.0 (θ ) 26.00°)
0.813 and 0.740
4822/0/282
0.895
completeness to θ (%)
max and min transm
data/restraints/params
GOF on F2
final R indices [I > 2σ(I)]
R1 ) 0.0422
wR2 ) 0.0481
R1 ) 0.1551
wR2 ) 0.0590
0.498 and -0.476
R1 ) 0.0505
wR2 ) 0.0634
R1 ) 0.1713
wR2 ) 0.0812
0.415 and -0.352
R1 ) 0.0608
wR2 ) 0.1184
R1 ) 0.1958
wR2 ) 0.1362
0.379 and -0.356
R1 ) 0.0392
wR2 ) 0.0788
R1 ) 0.0556
wR2 ) 0.0827
0.416 and -0.867
R indices (all data)
largest diff peak and
hole (e‚Å-3
)
350 Inorganic Chemistry, Vol. 44, No. 2, 2005

Ag(I) Complexes of N-2-Pyridyl Sulfonamide Ligands
X-ray Crystallography. Compounds 1, 2a,b, 3a,b, 5, 7, and 8
and the ligand HTs4mepy were mounted on a glass fiber and studied
at room temperature on a SIEMENS Smart CCD area-detector
diffractometer using graphite-monochromated Mo KR radiation (λ
) 0.710 73 Å). The crystal parameters and experimental details
for data collection are summarized in Table 2. Absorption correc-
tions were carried out using SADABS.30 All the structures were
solved by direct methods, except for [Ag4(Ms6mepy)4] (3a), which
was solved by the Patterson method. All structures were refined
by full-matrix least-squares based on F2.31 All non-hydrogen atoms
were refined with anisotropic displacement parameters, except for
[Ag2(Ms6mepy)2phen] (7) due to the poor quality of the crystal.
In this case the Squeeze program was used to correct the reflection
data for the diffuse scattering due to disordered solvent.32 In all
cases the hydrogen atoms were included in idealized positions and
refined with isotropic displacement parameters, except for the
hydrogen atoms bonded to pyridine nitrogen atoms on the HTs4mepy
ligand, which were located on a difference electron density map
and refined with isotropic displacement parameters. Atomic scat-
tering factors and anomalous dispersion corrections for all atoms
were taken from ref 33
Crystallographic data (excluding structure factors) for the
structures reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary publica-
tion nos. CCDC 241798-241806 (HTs4mepy, 1, 2a,b, 3a,b, 5, 7,
and 8). Copies of the data can be obtained free of charge on
application to CCDC, 12 Union Road, Cambridge CB21EZ, U.K.
(fax, (/44) 1223-336-033; E-mail, deposit@ccdc.cam.ac.uk).
Acknowledgment. This work was supported by Xunta
de Galicia (Spain) (Grant PGIDT00PXI20305PR) and by the
Ministerio de Ciencia y Tecnolog´ıa (Spain) (Grant BQU2002-
01819).
Supporting Information Available: Crystallographic data in
CIF format and additional tables and figures. This material is
available free of charge via the Internet at http://pubs.acs.org.
(30) Sheldrick, G. M. SADABS, An empirical absorption correction
program for area detector data; University of Go¨ttingen: Go¨ttingen,
Germany, 1996.
(31) Sheldrick, G. M. SHELX-97, Program for the solution and refinement
of crystal structures; University of Go¨ttingen: Go¨ttingen, Germany,
1997.
IC0490268
(32) Spek, A. L. Acta Crystallogr. 1990, A46, C34.
(33) Wilson, A. J. C. International Tables for Crystallography; Kluwer
Academic Publishers: Dordrecht, The Netherlands, 1992; Vol. C.
Inorganic Chemistry, Vol. 44, No. 2, 2005 351