Synthesis, structure, and multi-NMR studies of (Me4N)[A{M(SC{O}Ph)3}2] (A = Na, M = Hg; A = K, M = Cd or Hg)

Article abstract of DOI:10.1021/ic0000810

The compounds (Me₄N)[A{M(SC{O}Ph)₃}₂] (A = K, M = Cd (2); A = Na, M = Hg (3); and A = K, M = Hg (4)) were synthesized by reacting the appropriate metal chloride with A⁺PhC{O}S^- and Me₄NCl in the ratios 1:3:1 and 2:6:1. The structures of these compounds were determined by single-crystal X-ray diffraction methods. All the compounds are isomorphous, isostructural, and crystallized in the space group P1 with Z = 1. Single-crystal data for 2: a = 10.6670(2) A, b = 11.1522(2) A, c = 11.9294(2) A, α = 71.782(1)°, β = 85.208(1)°, γ = 69.418(1)°, V = 1261.40(4) A³, D(calc) = 1.528 g cm^-3. Single-crystal data for 3: a = 10.840(2) A, b = 10.946(4) A, c = 12.006(3) A, α = 72.18(2)°, β = 86.75(2)°, γ = 67.43(2)°, V = 1249.3(6) A³, D(calc) = 1.756 g cm^-3. Single-crystal data for 4: a = 10.4780(1) A, b = 11.2563(2) A, c = 11.9827(2) A, α = 71.574(1)°, β = 85.084(1)°, γ = 70.705(1)°, V = 1265.23(3) A³, D(calc) = 1.755 g cm^-3. In the [A{M(SC{O}Ph)₃}₂]^- anions, each M(II) atom is bonded to three thiobenzoate ligands through sulfur atoms, giving a trigonal planar MS₃ geometry. The carbonyl oxygen atoms from the two [M(SC{O}Ph)₃]^- anions are bonded to the alkali metal atom, providing an octahedral environment. Solution metal NMR studies showed the concentration-dependent dissociation of the alkali metal ions in the trinuclear anions.

Full text of DOI:10.1021/ic0000810

Inorg. Chem. 2000, 39, 3071-3074
3071
Synthesis, Structure, and Multi-NMR Studies of (Me4N)[A{M(SC{O}Ph)3}2] (A ) Na, M )
Hg; A ) K, M ) Cd or Hg)
Theivanayagam C. Deivaraj,† Philip A. W. Dean,*,‡ and Jagadese J. Vittal*,†
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117 543, and
Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7
ReceiVed January 25, 2000
The compounds (Me4N)[A{M(SC{O}Ph)3}2] (A ) K, M ) Cd (2); A ) Na, M ) Hg (3); and A ) K, M ) Hg
(4)) were synthesized by reacting the appropriate metal chloride with A+PhC{O}S- and Me4NCl in the ratios
1:3:1 and 2:6:1. The structures of these compounds were determined by single-crystal X-ray diffraction methods.
All the compounds are isomorphous, isostructural, and crystallized in the space group P1h with Z ) 1. Single-
crystal data for 2: a ) 10.6670(2) Å, b ) 11.1522(2) Å, c ) 11.9294(2) Å, R ) 71.782(1)°, â ) 85.208(1)°, γ
) 69.418(1)°, V ) 1261.40(4) Å3, Dcalc ) 1.528 g cm-3. Single-crystal data for 3: a ) 10.840(2) Å, b )
10.946(4) Å, c ) 12.006(3) Å, R ) 72.18(2)°, â ) 86.75(2)°, γ ) 67.43(2)°, V ) 1249.3(6) Å3, Dcalc ) 1.756
g cm-3. Single-crystal data for 4: a ) 10.4780(1) Å, b ) 11.2563(2) Å, c ) 11.9827(2) Å, R ) 71.574(1)°, â
) 85.084(1)°, γ ) 70.705(1)°, V ) 1265.23(3) Å3, Dcalc ) 1.755 g cm-3. In the [A{M(SC{O}Ph)3}2]- anions,
each M(II) atom is bonded to three thiobenzoate ligands through sulfur atoms, giving a trigonal planar MS3
geometry. The carbonyl oxygen atoms from the two [M(SC{O}Ph)3]- anions are bonded to the alkali metal
atom, providing an octahedral environment. Solution metal NMR studies showed the concentration-dependent
dissociation of the alkali metal ions in the trinuclear anions.
Introduction
to Na(I) ions to give an octahedral coordination geometry. Bond
valence calculations suggested that [Hg(SC{O}Ph)3]- should
be a better oxygen-donor metalloligand than [Cd(SC{O}Ph)3]-.15
However, to date, our attempts to prepare the trinuclear anions
based on [Hg(SC{O}Ph)3]- have resulted in alkali metal free
(Me4N)[Hg(SC{O}Ph)3] 16 or a salt of [Hg2Cl4(S{O}CPh)2]2- 17
as the only crystalline products. We remain interested in finding
out whether similar trinuclear groups 1-12 anions exist for
combinations of metal ions other than NaCd2. A wider group
of anions would allow an investigation of the way in which the
structural parameters and geometry of M(II) are influenced by
the presence of alkali metal ions more generally. Therefore, in
continuation of our investigations on the chemistry of metal
thiocarboxylate compounds,18-24 we describe here the syntheses
and structures of trinuclear groups 1-12 anions of type KCd2,
NaHg2, and KHg2 with thiobenzoate ligands. We have also
investigated the stability of these anionic species in solution by
metal NMR spectroscopy.
A number of macrocycles have been designed to complex
the alkali metal ions.1-6 However, only a few clawlike met-
alloligands have been found to form complexes with alkali
metals.7-13 A sodium ion bound to a clawlike metalloligand is
found in the [Na{Cd(SC{O}Ph)3}2]- anion.14 In this anion, the
soft sulfur atoms of the PhC{O}S- ligands are bonded to
Cd(II) ions to provide a planar CdS3 coordination geometry
around each Cd(II) center and the oxygen atoms are attached
* To whom correspondence should be addressed.
† National University of Singapore.
‡ The University of Western Ontario.
(1) Lindoy, L. F. In The Chemistry of macrocyclic ligand complexes;
Cambridge University Press: U.K., 1989.
(2) Constable, E. C. In Coordination chemistry of macrocyclic ligands;
Oxford University Press: New York, 1999.
(3) Cooper, S. R. In Crown compounds: toward future applications;
VCH: New York, 1992.
(4) Inoue, Y.; Gokel, G. W. In Cation binding by macrocycles: Com-
plexation of cationic species by crown ethers; Marcel Dekker: New
York, 1990.
(5) Cram, D. J.; Cram, J. M. Container Molecules and Their Guests. In
Monographs in Supramolecular Chemistry; Royal Society of Chem-
istry: Cambridge, 1994.
(6) Izattand, R. M.; Bradshaw, J. S. The Pedersen memorial issue; Kluwer
Academic Publications: Boston, 1992.
Experimental Section
General Methods. All materials were obtained commercially and
were used as received except for Na[BPh4], which was recrystallized
from Me2CO. All reactions were performed under an atmosphere of
(15) Vittal, J. J.; Dean, P.A. W. Inorg. Chem. 1996, 35, 3089.
(16) Vittal, J. J.; Dean, P. A. W. Acta Crystallogr. 1997, C53, 409.
(17) Vittal, J. J.; Dean, P. A. W. Polyhedron 1998, 17, 1937.
(18) Vittal, J. J.; Dean, P. A. W. Acta Crystallogr. 1998, C54, 319.
(19) Dean, P. A. W.; Vittal, J. J.; Craig, D. C.; Scudder, M. L. Inorg. Chem.
1998, 37, 1661.
(7) Veith, M. Chem. ReV. 1990, 90, 3.
(8) Steiner, A.; Stalke, D. J. Chem. Soc., Chem. Commun. 1993, 1702.
(9) Albrecht, M.; Blau, O.; Fro¨hlich, R. Chem. Eur. J. 1999, 5, 48.
(10) Saalfrank, R. W.; Lo¨w, N.; Hampel, F.; Stachel, H. D. Angew. Chem.,
Int. Ed. Engl. 1996, 35, 2209.
(11) Saalfrank, R. W.; Dresel, A.; Seitz, V.; Trummer, S.; Hampel, F.;
Teichert, M.; Stalke, D.; Stadler, C.; Daub, J.; Schu¨nemann, V.;
Trautwein, A. X. Chem. Eur. J. 1997, 3, 205.
(12) Saalfrank, R. W.; Bernt, I.; Uller, E.; Hampel, F. Angew. Chem., Int.
Ed. Engl. 1997, 36, 2482.
(13) Saalfrank, R. W.; Lo¨w, N.; Kareth, S.; Seitz, V.; Hampel, F.; Stalke,
D.; Teichert, M. Angew. Chem., Int. Ed. Engl. 1998, 37, 172.
(14) Vittal, J. J.; Dean, P. A. W. Inorg. Chem. 1993, 32, 791.
(20) Burnett, T. R.; Dean, P. A. W.; Vittal, J. J. Can. J. Chem. 1994, 72,
1127.
(21) Vittal, J. J.; Dean, P. A. W. Acta Crystallogr. 1997, C52, 1180.
(22) Devy, R.; Vittal, J. J.; Dean, P. A. W. Inorg. Chem. 1998, 37, 6939.
(23) Sampanthar, J. T.; Vittal, J. J.; Dean, P. A. W. J. Chem. Soc., Dalton
Trans. 1999, 3153.
(24) Sampanthar, J. T.; Deivaraj, T. C.; Vittal, J. J.; Dean, P. A. W. J.
Chem. Soc., Dalton Trans. 1999, 4419.
10.1021/ic0000810 CCC: $19.00 © 2000 American Chemical Society
Published on Web 06/13/2000

3072 Inorganic Chemistry, Vol. 39, No. 14, 2000
Table 1. Crystal Data and Experimental Details
Deivaraj et al.
2
3
4
empirical formula
fw
temp, °C
C46H42Cd2KNO6S6
1161.07
23
C46H42Hg2NaNO6S6
1321.34
23
C46H42Hg2KNO6S6
1337.45
23
radiation wavelength, Å
space group
a, Å
b, Å
Mo KR, 0.71073
Mo KR, 0.71073
Mo KR, 0.71073
P1h
P1h
P1h
10.6670(2)
11.1522(2)
11.9294(2)
71.782(1)
85.208(1)
69.418(1)
1261.40(4)
1
10.840(2)
10.946(4)
12.006(3)
72.18(2)
86.75(2)
67.43(2)
1249.3(6)
1
10.4780(1)
11.2563(2)
11.9827(2)
71.574(1)
85.084(1)
70.705(1)
1265.23(3)
1
c, Å
R, deg
â, deg
γ, deg
vol, Å3
Z
F observed, g/cm3
abs coeff, mm-1
final R indices [I > 2σ(I)]
R1a
1.528
1.219
1.756
6.442
1.755
6.435
0.0599
0.1304
0.0346
0.0797
0.0323
0.0864
wR2a
a R1 ) (||Fo| - |Fc||)/(|Fo|); wR2 ) [(w(Fo - Fc2)/(wFo ]1/2
.
2
4
N2(g). The literature method14 was used to prepare (Me4N)[Na{Cd-
(SC{O}Ph)3}2], 1. All nonaqueous solvents were dried over 3 Å
molecular sieves. They were degassed with N2(g) or Ar(g) before the
reactions or preparation of NMR samples. The yields are reported with
respect to the metal salts. The Microanalytical Laboratory at NUS
performed microanalyses.
for 113Cd, which has a negative Overhauser effect. Spectra were obtained
with the field preshimmed but without a field-frequency lock (field
drift is negligible). Temperatures were measured using a calibrated
thermocouple in a stationary dummy sample. External referencing was
carried out by sample interchange using 0.1 M Na[BPh4] in Me2CO at
294 ( 1 K, 0.1 M Cd(ClO4)2 (aq) at 294 ( 1 K and neat HgMe2 (as
a sealed sample. CAUTION! HIGHLY TOXIC!) at 296 ( 1 K for
23Na, 113Cd, and 199Hg, respectively. Samples were prepared in 10 mm
o.d. NMR tubes, with concentrations expressed as mass of solute/
volume of solvent.
X-ray Crystallography. Single crystals were obtained during the
synthesis. The diffraction experiments were carried out on a Bruker
SMART CCD diffractometer with a Mo KR sealed tube at 23 °C. The
collected frames were integrated using the preliminary cell-orientation
matrix. The softwares used were the following: SMART25 for collecting
frames of data, indexing reflection, and determining lattice parameters;
SAINT25 for integrating intensity of reflections and scaling; SADABS26
for correcting for absorption; and SHELXTL27 for determining space
group and structure, least-squares-refining on F2, and reporting graphics
and structure. The space groups were determined from the systematic
absences. Anisotropic thermal parameters were refined for all the non-
hydrogen atoms. All the C-H hydrogen atoms were placed in their
calculated positions and included in the structure factor calculations.
The carbon atoms of the Me4N+ cations were disordered. Two different
orientations with occupancies 0.5/0.5 were included. Common isotropic
thermal parameters were included for each model. A brief summary of
the crystallographic data is given in Table 1.
(Me4N)[K{Cd(SC{O}Ph)3}2], 2. A solution of CdCl2 (1.227 g, 6.09
mmol) in 10 mL of water was added to C6H5C{O}S-K+ prepared in
situ by reacting KOH (1.026 g, 18.29 mmol) in 15 mL of water with
C6H5C{O}SH (2.14 mL, 18.29 mmol) in 10 mL of methanol, followed
by the addition of Me4NCl (0.668 g, 6.09 mmol), which resulted in a
creamy white precipitate. To this mixture MeCN (12.5 mL) was added,
and the solution was warmed to get a near-clear solution. The solution
was filtered hot and left at 5 °C for crystallization. Creamy yellow
crystals were separated by filtration, washed with MeOH and Et2O,
and dried in vacuo. Yield: 2.10 g (59.3%). Anal. Calcd for C46H42-
Cd2KNO6S6 (mol wt 1161.07): C, 47.58; H, 3.65; S, 16.57; N, 1.21;
K, 3.37; Cd, 19.36. Found: C, 47.88; H, 3.23; S, 15.16; N, 1.47; K,
1
2.93; Cd, 18.13. H NMR (CD3CN): δ, ppm, 3.29 (12H, (CH3)4N),
7.38-8.16 (30H, C6H5C{O}S). 13C NMR (CD3CN): δ, ppm, 56.53
(N(CH3)4), 128.72 (C3/2), 129.33(C2/3), 132.75 (C4), 140.98(C1), 208.27-
(PhCOS).
(Me4N)[Na{Hg(SC{O}Ph)3}2], 3. The synthesis followed that of 2
closely but employed NaOH and HgCl2 (dissolved in 5 mL of MeOH)
in place of KOH and CdCl2, respectively. Yield: 66%. Anal. Calcd
for C46H42Hg2NaNO6S6 (mol wt 1321.34): C, 41.81; H, 3.20; N, 1.06;
Na, 1.74. Found: C, 41.69; H, 3.17; N, 1.19; Na, 1.85. 1H NMR (CD3-
CN): δ, ppm, 3.06 (12H, N(CH3)4), 7.38-8.11 (30H, C6H5C{O}S).
13C NMR (CD3CN): δ, ppm, 56.04 (N(CH3)4), 128.79 (C3/2), 129.00(C2/3),
132.70 (C4), 141.87(C1), 201.55 (PhCOS).
Results and Discusison
Synthesis. The compounds 2-4 were isolated from M(II)
salts, Me4NCl, and AS{O}CPh in the ratios 1:1:3 and 2:1:6
from a concentrated solution of water/MeOH/MeCN. Salts of
groups 1-12 anions did not crystallize from dilute solutions.
Instead (Me4N)[M(SC{O}Ph)3] was isolated. The same alkali
metal free salts resulted when attempts were made to recrystal-
lize 2-4 by diffusion methods. Evidently the trinuclear anions
dissociate on dilution. (This is confirmed by NMR studies; see
below.) Further, under experimental conditions similar to those
used to prepare 1-4, only the alkali metal free salt was isolated
for M ) Zn. The compounds 2-4 are soluble in MeCN and
(Me4N)[K{Hg(SC{O}Ph)3}2], 4. Compound 4 was obtained as
creamy yellow crystals when the synthesis was carried out as for 3 but
using KOH in place of NaOH. Yield: 71.3%. Anal. Calcd for C46H42-
Hg2KNO6S6 (mol wt 1337.45): C, 41.31; H, 3.17; N, 1.05; K, 2.92.
1
Found: C, 41.03; H, 3.18; N, 1.27; K, 3.12. H NMR (CD3CN): δ,
ppm, 3.07 (12H, (CH3)4N), 7.38-8.10 (30H, C6H5C{O}S). 13C NMR
(CD3CN): δ, ppm, 56.01 (N(CH3)4), 128.80 (C3/2), 128.99 (C2/3), 132.70
(C4), 141.84 (C1), 201.16 (PhCOS).
Compounds 2-4 were also obtained when the starting materials Me4-
NCl, metal salt, and alkali thiobenzoate were in the ratio 1:2:6. Under
similar experimental conditions, the zinc chloride yielded only (Me4N)-
[Zn(SC{O}Ph)3].
NMR Spectra. Proton and 13C{1H} NMR spectra were recorded at
298 K on a Bruker ACF 300 MHz spectrometer. Samples were made
up in 5 mm o.d. NMR tubes with CD3CN as solvent and TMS as
internal reference. Metal NMR spectra were obtained using a Varian
XL-300 spectrometer system operating at 97.34, 66.53, and 53.72 MHz
for 23Na, 113Cd, and 199Hg, respectively. No proton-decoupling was used
for 23Na. Proton-decoupling was continuous for 199Hg but inverse-gated
(25) SMART & SAINT Software Reference Manuals, version 4.0; Analytical
Instrumentation, Siemens Energy & Automation, Inc.: Madison, WI,
1996.
(26) Sheldrick, G. M. SADABS (software for empirical absorption correc-
tion); University of Go¨ttingen: Go¨ttingen, Germany, 1996.
(27) SHELXTL Reference Manual, version 5.03; Analytical Instrumentation,
Siemens Energy & Automation, Inc.: Madison, WI, 1996.

(Me4N)[A{M(SC{O}Ph)3}2]
Inorganic Chemistry, Vol. 39, No. 14, 2000 3073
Table 2. Selected Distances [Å] and Angles [deg] for 2-4a
parameters
2
3
4
A-M
3.8376(5)
2.688(4)
2.685(4)
2.676(5)
2.482(2)
2.492(2)
2.532(2)
2.811(3)
2.892(3)
3.003(3)
1.725(6)
1.738(6)
1.740(6)
1.217(6)
1.226(6)
1.216(7)
1.507(7)
1.489(7)
1.498(7)
3.7108(7)
2.447(4)
2.443(3)
2.331(4)
2.443(2)
2.485(2)
2.468(2)
3.059(3)
3.036(3)
2.978(3)
1.743(6)
1.743(5)
1.740(5)
1.217(6)
1.214(5)
1.216(5)
1.493(7)
1.489(7)
1.490(6)
3.8274(2)
2.680(4)
2.718(3)
2.736(4)
2.441(1)
2.496(1)
2.501(1)
3.062(2)
3.055(2)
3.208(2)
1.739(5)
1.733(5)
1.770(5)
1.219(6)
1.230(6)
1.214(6)
1.495(6)
1.517(6)
1.502(7)
A-O(1)
A-O(2)
A-O(3)
M-S(1)
M-S(2)
M-S(3)
M-O(1)
M-O(2)
M-O(3)
S(1)-C(1)
S(2)-C(2)
S(3)-C(3)
O(1)-C(1)
O(2)-C(2)
O(3)-C(3)
C(1)-C(11)
C(2)-C(21)
C(3)-C(31)
Figure 1. ORTEP diagram (with 50% probability thermal ellipsoids)
of the [K{Hg(SC{O}Ph)3}2]- anion. The hydrogen atoms are omitted
for clarity.
O(3)-A-O(2)
O(3)-A-O(2A)
O(3)-A-O(1A)
O(2)-A-O(1A)
O(3)-A-O(1)
O(2)-A-O(1)
S(1)-M-S(2)
S(1)-M-S(3)
S(2)-M-S(3)
C(1)-S(1)-M
C(2)-S(2)-M
C(3)-S(3)-M
C(1)-O(1)-A
C(2)-O(2)-A
C(3)-O(3)-A
O(1)-C(1)-S(1)
C(11)-C(1)S(1)
O(2)-C(2)-S(2)
C(21)-C(2)-S(2)
O(3)-C(3)-S(3)
C(31)-C(3)-S(3)
92.8(2)
87.2(2)
101.7(1)
107.9(1)
78.3(1)
95.0(1)
85.0(1)
90.8(1)
97.0(1)
89.2(1)
83.0(1)
115.31(6)
130.08(6)
114.39(6)
96.6(2)
101.2(1)
78.8(1)
95.7(1)
103.6(1)
84.3(1)
76.4(1)
120.97(5)
133.52(5)
105.45(5)
97.4(2)
acetone and insoluble in CH2Cl2 and CHCl3, whereas the
corresponding alkali metal free Ph4P+ and Ph4As+ salts are
freely soluble in CH2Cl2 and CHCl3. The Me4N+ cation appears
to be important for the isolation of salts of the trinuclear anions.
Structural Description of Compounds 2-4. The common
features in compounds 2-4 are summarized below. All the three
compounds and 1 are isomorphous and isostructural and consist
of discrete anions and cations in the crystal lattice. The Me4N+
cations in all the compounds were found to be disordered. The
[A{M(SC{O}Ph)3}2]- anion (A ) Na, K for M ) Hg; A ) K
for M ) Cd) is trinuclear, with an alkali metal ion sandwiched
between two [M(SC{O}Ph)3]- anions by coordinating to all six
carbonyl oxygens of the PhC{O}S- ligands. The M(II) ion in
each [M(SC{O}Ph)3]- anion is S-bonded by three thiobenzoate
anions to have a near-trigonal-planar geometry. The alkali metal
atom is located at the center of inversion in the molecule and
has a distorted octahedral geometry. A representative structure
of the anions, that of [K{Hg(S{O}CPh)3}2], is shown in Figure
1, and selected bond distances, angles, and other relevant
parameters are displayed in Table 2. The three M-S distances
for each compound were unequal. The average Cd-S bond
distance in 2 is very slightly less than that of the corresponding
Hg-S distances in 3 and 4, a trend that has been observed for
the metalloligands themselves.16-18 The sums of the S-M-S
angles are close to 360°, and the distances of M(II) from the S3
planes are very small (Table 2), indicating a trigonal planar MS3
geometry in each anion. In 2, the Cd is closer to the S3 plane
(Table 2) than in 1 where the Cd is moved away from S3 plane,
toward Na, by 0.326 Å. The Cd‚‚‚O distances in 2
(2.811-3.003 Å) are longer than those found in 1 (2.659-2.828
Å), and bond valence calculations28 show that there is a
reduction in M-O contribution from 15.0% in 1 to 10.5% in
2.
72.2(1)
120.21(6)
130.85(6)
108.43(6)
90.7(2)
92.5(2)
96.6(2)
148.0(4)
166.6(4)
116.4(4)
122.2(4)
117.4(4)
122.1(4)
117.5(4)
119.4(5)
118.5(4)
95.8(2)
96.3(2)
96.2(2)
101.3(2)
145.1(4)
164.8(4)
109.4(3)
123.1(4)
116.7(3)
119.0(5)
117.3(3)
120.7(4)
117.0(3)
153.8(4)
160.5(3)
140.0(4)
123.9(4)
115.5(4)
123.3(4)
116.1(3)
120.4(4)
118.5(3)
distance of M
from S3 plane
dihedral angle between
MSOC planes
-0.102
-0.066
0.034
68.7(1)
73.0(1)
66.0(1)
87.6(1)
70.3(1)
33.1(2)
76.7(1)
60.0(1)
37.8(2)
83.3(1)
70.4(1)
35.1(2)
dihedral angle between
SOCC plane and Ph ring
18.9(3)
10.5(3)
17.8(3)
5.9(3)
18.2(2)
15.3(3)
a Symmetry operator for the atoms with the extension A: 1 - x, 1
- y, 1 - z.
[M(SC{O}Ph)3]- anions is the orientation of carbonyl groups.
In compounds 1-4 they are oriented on one side of the MS3
plane, while they are random in the alkali metal free metallo-
ligands, with the exception of the type A anions in rhombohedral
(Ph4P)[Cd(S{O}CPh)3].19 The Na‚‚‚O distances found in 3 are
normal and comparable to the range 2.130-2.978 Å reported
for six-coordinated Na-O distances.29 Similarly, the K‚‚‚O
distances observed in 2 and 4 fall within the range 2.811(3)-
3.208(2) Å, which is normal for six-coordinated K-O dis-
tances.30 The MS3 kernels observed in the thiobenzoate com-
plexes of group 12 metals have the unusual trigonal planar
geometry (this work and refs 14-16, 18). Normally, this
geometry is observed for group 12 metals only in the presence
of thiolate31 or phenolate32 ligands having bulky substituents.
A complete set of data for a meaningful comparison is
available for NMe4+ salts of Hg. While average Hg-S distances
are not affected by alkali metal complexation, the average
Hg-O distances are in the order (Me4N)[Hg(SC{O}Ph)3] < 3
< 4. The sum of the S-Hg-S angles is close to 360° for all
three compounds, and the deviation from planarity is also less
than 0.07 Å. In other words, the complexation with alkali metal
ions does not affect the MS3 planarity and only the orientations
of the carbonyl groups are affected. The main structural
difference between compounds 1-4 and the alkali free
(28) Brown, I. D.; J. Appl. Crystallogr. 1996, 29, 479.
(29) Wood, R. M.; Palenik, G. J. Inorg. Chem. 1999, 38, 3926.

3074 Inorganic Chemistry, Vol. 39, No. 14, 2000
Deivaraj et al.
Metal NMR Studies in Solution. The 113Cd NMR chemical
shifts of 2 in Me2CO and MeCN (Supporting Information) are
similar to those of 1 in the same solvents. For example, δCd(1)
) 292.3 and 300.7 ppm in Me2CO and MeCN, respectively, at
296 K when the concentration is 0.025 mol/L of solvent,14 while
the corresponding values for 2 are 287.9 and 294.8 ppm. Thus,
it is clear that the Cd(S{O}CPh)3 moiety is intact in 2. Evidently,
the change in Cd‚‚‚O distances from 1 to 2 (see above) causes
little difference in the (exchange-averaged) 113Cd NMR chemical
shifts. This suggests that the chemical shifts may be a reflection
of the electronic properties of the ligand as an S donor rather
than a manifestation of the weak M‚‚‚O interaction, as we have
previously assumed.14
The metal NMR spectra of 1:1 mixtures (0.025 mol/L of Me2-
CO for each component) of 1/3 and 2/4 at 178 K consisted of
just one 113Cd NMR signal and one 199Hg NMR signal; δCd
(approximate ∆ν1/2) and δHg (approximate ∆ν1/2) were 291 (175
Hz) and -810 (200 Hz) for the 1/3 mixture and 283.8 (20 Hz)
and -801 (375 Hz) for the 2/4 mixture. Thus, there was no
evidence for the trinuclear anions with mixed metalloligands,
[{(PhC{O}S)3M}A{M′(S{O}CPh)3}]-, under these conditions
and, by extension, no evidence that the various anions
[A{M(S{O}CPh)3}2]- remain intact under these conditions.
Although the result for the 1/3 mixture is rendered ambiguous
by the relatively broad lines that are observed for both nuclei,
that for the 2/4 mixture is less so because the 113Cd resonance
at least is quite sharp. Evidently, either rapid exchange of
metalloligands persists at reduced temperature in the 2/4 mixture
or the 113Cd resonances of [{(PhC{O}S)3Cd}K{Hg(S{O}CPh)3}]-
and [K{Cd(S{O}CPh)3}2]- are accidentally degenerate.
As is the case with 1,14 the values of δCd for 2 decrease with
increasing dilution, reaching the value for [Cd(S{O}CPh)3]-
itself, 291 ppm for a solution containing 0.002 mol of (Ph4-
As)[Cd(S{O}CPh)3]/L of MeCN at 294 K.15 It is clear that the
trinuclear anion in 2 is extensively dissociated according to
Addition of Na[BPh4] to a solution of 3 causes the exchange-
averaged 199Hg resonance to become increasingly shielded
(Supporting Information). The signal must approach the chemi-
cal shift of [Na{Hg(S{O}CPh)3}], which must therefore be less
than -853 ppm in Me2CO and less than -855 ppm in MeCN.
On the assumption that the dissociation of eq 1, A ) Na and
M ) Hg, is complete while that of eq 2 is not, the ∆δHg data
for the 3/Na[BPh4] mixtures together with those obtainable from
K1
\z
[A{M(S{O}CPh)3}2]- y
[A{M(S{O}CPh)3}] + [M(S{O}CPh)3]- (1)
and
δ
Hg for solutions of 3 alone (Table 3) should fit the equation33
∆δHg ) P([Na{Hg(S{O}CPh)3}])
∆δHg([Na{Hg(S{O}CPh)3}]) (3)
K2
\
[A{M(S{O}CPh)3}] y
z [M(S{O}CPh)3]- + A+ (2)
where A ) K, M ) Cd, at the lowest concentration used.
Furthermore, the exchange among [Cd(S{O}CPh)3]-, [KCd-
(S{O}CPh)3], and [K{Cd(S{O}CPh)3}2]- is evidently fast at
ambient probe temperature.
(where P([Na{Hg(S{O}CPh)3}]) )
fractional population of Hg as [Na{Hg(S{O}CPh)3}])
for some value of K2. However, no value of K2 could be found
that gave a completely satisfactory fit in terms of a sensible
slope, sensible intercept, and reasonable scatter pattern. We
conclude therefore that the first dissociation is not complete
and that in general these solutions contain all three compounds
[Na{Hg(S{O}CPh)3}2]-, [Na{Hg(S{O}CPh)3}], and [Hg(S-
{O}CPh)3]-. Unfortunately, there are insufficient data to obtain
the two values of K and ∆δHg for the two coupled equilibria.
The 199Hg NMR spectra of 3 and 4 at 298 K (Supporting
Information) show signals in the region expected for the Hg-
(S{O}CPh)3 moiety.15 With dilution, δHg for samples in Me2-
CO tend toward that of [Hg(S{O}CPh)3]- (-781 ppm (ap-
proximately ∆ν1/2 ) 120 Hz) for a saturated solution of
+
(PPh4)[Hg(S{O}CPh)3] in Me2CO; the PPh4 salt is insuf-
ficiently soluble in MeCN to make 199Hg NMR spectroscopy
of its MeCN solutions worthwhile). Dissociation according to
eqs 1 and 2 is again indicated, with exchange between the
components of the equilibrium mixture being fast on the time
scale of ∆δHg. The values of ∆δNa for solutions of 3 (Supporting
Information) confirm that for this salt dissociation of the
trinuclear anion to Na+ and [Hg(S{O}CPh)3]- is not complete
even at the lowest concentration studied (0.001 mol of 3/L of
solvent).
Acknowledgment. J.J.V. thanks the National University of
Singapore for a research grant (Grant RP970618), and P.A.W.D.
thanks the Natural Sciences and Engineering Research Council
of Canada for financial support.
Supporting Information Available: Metal NMR data for 2-4 and
for 3/Na[BPh4] mixtures at 298 K and X-ray crystallographic files in
CIF format for the structure determinations of complexes 2-4. This
material is available free of charge via the Internet at http://pubs.acs.org.
(30) Wood, R. M.; Palenik, G. J. Inorg. Chem. 1999, 38, 1031.
(31) Dilworth, J. R.; Hu, J. AdV. Inorg. Chem. 1994, 40, 411.
(32) Darensburg, D. J.; Niezgoda, S. A.; Draper, J. D.; Reibenspies, J. H.
Inorg. Chem. 1999, 38, 1356.
IC0000810
(33) Foster, R.; Fyfe, C. A. Prog. Nucl. Magn. Reson. Spectrosc. 1969, 4,
1.