Chemistry of thiobenzoates: syntheses, structures, and NMR spectra of salts of [M(SOCPh)3]- (M = Zn, Cd, Hg)

Article abstract of DOI:10.1021/ic9514298

The salts (Ph₄E)[M(SOCPh)₃] (M = Zn, Cd, or Hg; E = P or As) are produced by the reaction of Zn(NO₃)₂?6 H₂O, Cd(NO₃)₂·4H₂O or HgCl₂ with Et₃NH⁺PhCOS^- and (Ph₄E)X (E = P, X = Br; E = As, X = Cl) in aqueous MeOH in the ratios M(II):PhCOS^-:Ph₄E⁺ = 1:≥ 3:≥ 1. The crystal structures of (Ph₄P)[Zn(SOCPh)₃] (1), (Ph₄-As)[Cd(SOCPh)₃] (2) and (Ph₄P)[Hg(SOCPh)₃] (3) have been determined by single-crystal X-ray diffraction experiments. Crystal data for 1: triclinic; space group P1; Z = 2; a = 10.819(2) ?, b = 13.219(3) ?, c = 15.951(3) ? α = 101.75(2)°, β = 97.92(1)°, γ = 109.18(2)°. Crystal data for 2: triclinic; space group P1; Z = 2; a = 10.741(2) ?, b = 13.168(2) ?, c = 15.809(2) ?; α = 101.00(1)°, β= 97.65(1)°, γ = 109.88(1)°. Crystal data for 3: monoclinic; space group P2₁/n; Z = 4; a = 13.302(2) ?, b = 14.276(2) ?, c = 21.108(2) ?; β = 90.92(1)°. The compounds 1 and 2 are isomorphous and isostructural. In the anions [M(SOCPh)₃]^- the metal atoms have trigonal planar coordination by three sulfur atoms. The metal atoms are further more weakly coordinated intramolecularly to one (M = Hg) or two (M = Zn, Cd) thiobenzoate oxygen atom(s). Using the Bond Valence approach it is found that the contribution of M?O bonding to the total bonding is in the order Cd > Zn > Hg. The metal (¹¹³Cd, ¹¹³Hg) NMR signals of [M(SOCPh)₃]^- (M = Cd, Hg) are more shielded than those found for MS₃ kernels in thiolate complexes, a difference attributed to the MO bonding in the thiobenzoate complexes. The ¹¹³Cd resonance of [Cd(SOCPh)₃]^- in dilute solution is in the region anticipated from dilution data for [Na(Cd{SOCPh}₃)₂]^-.

Full text of DOI:10.1021/ic9514298

Inorg. Chem. 1996, 35, 3089-3093
3089
Chemistry of Thiobenzoates: Syntheses, Structures, and NMR Spectra of Salts of
[M(SOCPh)3]- (M ) Zn, Cd, Hg)
Jagadese J. Vittal and Philip A. W. Dean*
Department of Chemistry, University of Western Ontario, London, Ontario N6A 5B7, Canada
ReceiVed NoVember 2, 1995X
The salts (Ph4E)[M(SOCPh)3] (M ) Zn, Cd, or Hg; E ) P or As) are produced by the reaction of Zn(NO3)2‚6
H2O, Cd(NO3)2‚4H2O or HgCl2 with Et3NH+PhCOS- and (Ph4E)X (E ) P, X ) Br; E ) As, X ) Cl) in aqueous
MeOH in the ratios M(II):PhCOS-:Ph4E+ ) 1:g3:g1. The crystal structures of (Ph4P)[Zn(SOCPh)3] (1), (Ph4-
As)[Cd(SOCPh)3] (2) and (Ph4P)[Hg(SOCPh)3] (3) have been determined by single-crystal X-ray diffraction
experiments. Crystal data for 1: triclinic; space group P1h; Z ) 2; a ) 10.819(2) Å, b ) 13.219(3) Å, c )
15.951(3) Å; R ) 101.75(2)°, â ) 97.92(1)°, γ ) 109.18(2)°. Crystal data for 2: triclinic; space group P1h; Z
) 2; a ) 10.741(2) Å, b ) 13.168(2) Å, c ) 15.809(2) Å; R ) 101.00(1)°, â ) 97.65(1)°, γ ) 109.88(1)°.
Crystal data for 3: monoclinic; space group P21/n; Z ) 4; a ) 13.302(2) Å, b ) 14.276(2) Å, c ) 21.108(2) Å;
â ) 90.92(1)°. The compounds 1 and 2 are isomorphous and isostructural. In the anions [M(SOCPh)3]- the
metal atoms have trigonal planar coordination by three sulfur atoms. The metal atoms are further more weakly
coordinated intramolecularly to one (M ) Hg) or two (M ) Zn, Cd) thiobenzoate oxygen atom(s). Using the
Bond Valence approach it is found that the contribution of M‚‚‚O bonding to the total bonding is in the order Cd
> Zn > Hg. The metal (113Cd, 199Hg) NMR signals of [M(SOCPh)3]- (M ) Cd, Hg) are more shielded than
those found for MS3 kernels in thiolate complexes, a difference attributed to the M...O bonding in the thiobenzoate
complexes. The 113Cd resonance of [Cd(SOCPh)3]- in dilute solution is in the region anticipated from dilution
data for [Na(Cd{SOCPh}3)2]-.
Introduction
Experimental Section
General Procedure. All the preparations were carried under Ar,
with solvents that had been sparged with Ar. As solids, the new
compounds are stable in air at room temperature for days at least. For
longer period of time they were normally stored under Ar at 5 °C.
Solutions of these materials under Ar were stable for days at room
temperature.
The ligand behavior of monothiocarboxylates has not been
very extensively studied.1-3 However, the ligands RCOS- are
interesting because they contain both a soft sulfur donor site
and a hard oxygen donor site, and the presence of these disparate
sites can lead to aggregation of soft and hard metal centers. An
example is provided by the structure of (Me4N)[Na{Cd-
(SCOPh)3}2], which we reported recently.3 In the [Na{Cd-
(SCOPh)3}2]- anion, the relatively soft Cd(II) is bound pref-
erentially to the sulfur atoms, giving nearly trigonal planar
coordination, while the relatively hard Na(I) is attached to six
oxygen atoms. Planar CdS3 kernels are uncommon. In thiolato-
species, [Cd(SR)3]- or RSCd(µ-SR)2CdSR, they are known only
for particularly bulky R groups.4-6 Since the formation of a
CdS3 kernel in [Na{Cd(SCOPh)3}2]- might be influenced by
the interaction of the SCOPh- ligands with the Na+ ion, we
felt it important to investigate the geometry about the Cd(II) in
[Cd(SCOPh)3]- itself. Accordingly, we report here the syn-
theses and characterization of salts of [Cd(SOCPh)3]-. For
additional comparison, we have extended our studies to include
salts of [M(SCOPh)3]- (M ) Zn, Hg). In thiolates, the kernels
MS3 (M ) Zn, Hg) are also formed only (M ) Zn7,8) or mainly
(M ) Hg4,5,9) with bulky thiolates.
(Ph4P)[Zn(SOCPh)3] (1). Et3NH+ SCOPh- was prepared in situ
by mixing Et3N (1.72 g, 17.0 mmol) in 20 mL of MeOH with
thiobenzoic acid (2.35 g, 17.0 mmol). To this stirred solution was added
Zn(NO3)2‚6H2O (1.69 g, 5.68 mmol) in 15 mL of H2O. The resultant
yellow solution with some viscous orange oil at the bottom was treated
with Ph4PBr (2.38 g, 5.66 mmol) in 20 mL of MeOH, and the mixture
was heated to boiling, giving a clear yellow solution. The solution
was filtered while hot and left in the refrigerator at 5˚C for crystal-
lization. The dark yellow crystals were separated by filtration, washed
with MeOH and Et2O, and then dried in a flow of Ar (yield 2.51 g).
The washings were combined with the filtrate and allowed to evaporate
at room temperature to get a second crop of crystals (yield 1.44 g).
Total isolated yield 3.95 g (85%). Anal. (crop II) Calcd for
C45H35O3P1S3Zn1 (mol wt 816.33): C, 66.21; H, 4.32. Found: C, 65.63,
65.71; H, 4.19, 4.24. 13C NMR of anion10 (CH2Cl2): δ 206.8
(PhC(O)S), 140.7 (C1), 131.8 (C4), 128.9 (C2/6 or C3/5), 127.9 (C3/5 or
C2/6).
(Ph4As)[Zn(SOCPh)3]. This preparation was essentially the same
as that of 1. However, the amounts of the starting materials were as
follows: Zn(NO3)2‚6 H2O, 0.63 g, 2.1 mmol; Ph4AsCl‚H2O, 1.79 g,
4.10 mmol; PhCOSH, 2.36 g, 17.1 mmol; Et3N, 1.72 g, 17.0 mmol.
The yield of orange needles was 1.56 g, 86%. Anal. Calcd for
C45H35O3As1S3Zn1 (mol wt 860.28): C, 62.83; H, 4.10. Found: C,
X Abstract published in AdVance ACS Abstracts, April 15, 1996.
(1) Cras, J. A.; Willemse, J. In ComprehensiVe Coordination Chemistry;
Wilkinson, G.; Gillard, R. D.; McCleverty, J. A., Eds.; Pergamon:
Oxford, England, 1987. Chapter 16.4.
(2) McCormick, B. J.; Beremon, R.; Baird, D. Coord. Chem. ReV. 1984,
54, 99.
(3) Vittal, J. J.; Dean, P. A. W. Inorg. Chem. 1993, 32, 791.
(4) Gruff, E. S.; Koch, S. A. J. Am. Chem. Soc. 1990, 112, 1245.
(5) Santos, R. A.; Gruff, E. S.; Koch, S. A.; Harbison, G. S. J. Am. Chem.
Soc. 1991, 113, 469.
(6) Bochmann, M.; Webb, K.; Harman, M.; Hursthouse, M. B. Angew.
Chem. 1990, 102, 703; Angew. Chem., Int. Ed. Engl. 1990, 29, 638.
(7) Gruff, E. S.; Koch, S. A. J. Am. Chem. Soc. 1989, 111, 8762.
(8) Bochmann, M.; Bwembya, G.; Grinter, R.; Lu, J.; Webb, K. J.;
Williamson, D. J.; Hursthouse, M. B.; Mazid, M. Inorg. Chem. 1993,
21, 532.
(9) Christou, G.; Folting, K.; Huffman, J. C. Polyhedron 1984, 3, 1247.
(10) Carbon-13 NMR spectrum of PPh4+ (CH2Cl2): 136.0 (C4,4J(P-C) )
3 Hz), 134.7 (C2,6, ,
2J(P-C) ) 10 Hz), 130.9 (C3,5 3J(P-C) ) 13
1
Hz), 117.7(C1, J(P-C) ) 90 Hz).
S0020-1669(95)01429-7 CCC: $12.00 © 1996 American Chemical Society

3090 Inorganic Chemistry, Vol. 35, No. 11, 1996
Vittal and Dean
62.56; H, 4.10. 13C NMR of anion11 (CH2Cl2): δ 206.7 (PhC(O)S),
140.9 (C1), 131.7 (C4), 128.8 (C2/6 or C3/5), 127.9 (C3/5 or C2/6).
Preliminary X-ray data of the crystals obtained in crop I and crop II
indicated that they are isomorphous with the Ph4P+ salts. Cell data:
yellow form, crop I, monoclinic, a ) 13.252(7) Å, b ) 14.302(6) Å,
c ) 21.164(11) Å, â ) 91.42(4)°, V ) 4010(3) Å3; Red form, crop II,
monoclinic, a ) 13.277(9) Å, b ) 14.323(7) Å, c ) 21.144(6) Å, â )
91.37(4)°, V ) 4020(4) Å3.
(Ph4P)[Cd(SOCPh)3]. Solid PhCOSH (2.35 g, 17.0 mmol) was
added to Et3N (1.72 g, 17.0 mmol) in 20 mL of MeOH. To the mixture
was added a solution of Cd(NO3)2‚4H2O (1.75 g, 5.67 mmol) in 15
mL of H2O, producing a pale yellow solution with some yellow oil at
the bottom. A light yellowish white precipitate was obtained on
addition of Ph4Br (2.38 g, 5.67 mmol) in 20 mL of MeOH. Addition
of MeCN (20 mL) plus 5 mL of CH2Cl2 produced a clear yellow
solution, which was left at 5 °C overnight. The bright yellow crystals
so produced were isolated by decantation, then washed and dried (yield
3.27 g), and a second crop obtained, as for 1 (yield 0.82 g). Total
yield 4.09 g (84%). Anal. (crop I) Calcd for C45H35Cd1O3P1S3 (mol
wt 863.35): C, 62.60; H,4.09. Found: C, 62.42; H, 3.91. 13C NMR
of anion10 (CH2Cl2): δ 207.7 (PhC(O)S), 140.7 (C1), 131.7 (C4), 129.2
(C2/6 or C3/5), 127.8 (C3/5 or C2/6).
NMR Spectra. Samples for both 13C and metal NMR spectroscopy
were prepared in Ar-flushed 10 mm o.d. NMR tubes, using solvents
that had been sparged with Ar. The concentration in all cases was 0.1
mol of solute/L of solvent.
Proton-decoupled 13C NMR spectra were obtained at 50.30 MHz
and 296 ( 1 K using a Varian Gemini-200 spectrometer system. After
preshimming of the field, no 2D lock was used. Field drift was
negligible. Chemical shifts were measured relative to a solvent signal
as primary reference (δC(CH2Cl2) ) 54.25; δC(H3CCN) ) 1.82).
Cadmium-113 and 199Hg NMR spectra were measured using a Varian
XL-300 spectrometer system operating at 66.53 and 53.72 MHz,
(Ph4As)[Cd(SOCPh)3] (2). The synthesis was similar to that of
the Ph4P+ salt except that Ph4AsCl‚HCl‚xH2O was used instead of Ph4-
PBr. Total yield: 3.86 g (∼75%). Anal. Calcd for C45H35As1Cd1O3S3
(mol wt 907.30): C, 59.57; H, 3.89. Found: C, 59.76; H, 3.75. 13C
NMR of anion11 (CH2Cl2): δ 207.7 (PhC(O)S), 140.7 (C1), 131.7 (C4),
129.2 (C2/6 or C3/5), 127.8 (C3/5 or C2/6).
The same product (characterized by 13C and 113Cd NMR) was
obtained in 87% yield using the same conditions but the following
amounts of reagents: Cd(NO3)2‚4H2O, 0.63 g, 2.0 mmol; Ph4AsCl‚H2O,
1.72 g, 3.94 mmol; PhCOSH, 2.25 g, 16.3 mmol; Et3N, 1.65 g, 16.3
mmol.
2
respectively, again with no D lock. Typically, 113Cd spectra were
obtained using a spectral window of 2.5 kHz, pulse width of 13.7 µs
(ca. 73°), acquisition time of 1 s (2.5 W decoupling), and a 4 s delay
(decoupler off). Typical conditions for measurement of 199Hg NMR
spectra were as follows: continuous 2.5 W decoupling, spectral window
5 kHz, pulse width 18 µs (ca. 90°), and acquisition time and cycle
time 1 s.
External referencing of the metal NMR spectra was achieved by
sample interchange, using 0.1 M Cd(ClO)4(aq) at 296 K and pure
HgMe2 at 297 K for 113Cd and 199Hg, respectively. Chemical shifts
were found to be reproducible to better than (1 ppm and ca. (2 ppm
for 113Cd and 199Hg, respectively.
X-ray Structure Determination. The single crystals were obtained
during the syntheses, as described. All the crystals are stable in air
and were mounted at the end of a glass fiber using epoxy glue for
diffraction experiments. The density measurements were made by the
neutral buoyancy method. The diffraction experiments were carried
out on a Siemens P4 diffractometer with the XSCANS software
package12 using graphite-monochromated Mo KR radiation at 23(2)
°C. The cell constants were obtained by centering 25 high angle
reflections. The data were collected in θ-2θ scan mode at variable
scan speeds (2-10 deg/min). Background measurements were made
at the ends of the scan range. Three or four standard reflections were
monitored at the end of every 297 reflections. The Laue symmetries
were determined by merging equivalent reflections, and the space
groups were determined from the systematic absences. SHELXTL13
programs were used for data processing, solution, and the least-squares
refinements (on F2). All the non-hydrogen atoms in the anions and
the P and As atoms were refined anisotropically. Isotropic thermal
parameters were refined for the carbon atoms of the phenyl rings in
the cation. Two-fold symmetry constraints were applied to the phenyl
rings of the cations Ph4E+ (E ) P or As). All the hydrogen atoms
were placed in calculated ideal positions for the purpose of structure
(Ph4P)[Hg(SOCPh)3] (3). A 2.1 g portion of liquid PhCOSH (15
mmol) was added to Et3N (1.44 g, 14.2 mmol) in 15 mL of MeOH. To
the stirred mixture was added a solution of HgCl2 (1.29 g, 4.75 mmol)
in 10 mL of MeOH by syringe very close to the surface, to produce a
clear yellow solution. (Addition of the HgCl2 in this way is necessary
to avoid any formation of black particles.) Upon addtion of Ph4PBr
(1.99 g, 4.75 mmol) in 10 mL of MeOH, a bright lemon yellow
precipitate was formed, which on continued stirring slowly underwent
partial dissolution. After addition of MeCN (10 mL) and CH2Cl2 (10
mL), the mixture was heated to ca. 50 °C for ca. 10 min, giving a
clear yellow solution. This was allowed to cool to room temperature
(ca. 20 min), then refrigerated at 5 °C overnight, producing long yellow
needles. The crystalline product was isolated as for the Cd analogue.
Yield: 3.69 g. The washings were combined with the decantate and
kept at room temperature. On partial evaporation of the solvent, many
light pink blocklike crystals were formed, contaminated with a small
amount of black powder. These crystals were separated, washed with
MeOH and Et2O and dried in Ar. Yield: 0.39 g. Total yield isolated:
90%. Anal. (crop I) Calcd for C45H35Hg1O3P1S3 (mol wt 951.53): C,
56.80; H, 3.71. Found: C, 57.10: H, 3.58. 13C NMR of anion10 (CH2-
Cl2): δ 199.7 (PhC(O)S), 141.4 (C1), 131.8 (C4), 128.8 (C2/6 or C3/5),
128.0 (C3/5 or C2/6).
The blocklike pink crystals were used for the single-crystal X-ray
diffraction studies. A preliminary determination of cell data of the
yellow crystals obtained in the first crop confirmed that it is isomor-
phous to the pink form. Cell data (25 °C): monoclinic, Laue symmetry
2/m, a ) 13.227(1) Å, b ) 14.297(2) Å, c ) 21.142(2) Å, â ) 90.82-
(1)°, V ) 3997.5(9) Å3.
(Ph4As)[Hg(SOCPh)3]. The synthetic procedure was similar to that
used for 3. However, the reagents HgCl2 (0.65 g, 2.4 mmol, in 10 mL
of MeOH), PhCOSH (1.47 g, 10.6 mmol), Et3N (0.97 g, 9.6 mmol, in
15 mL of MeOH) and Ph4AsCl‚H2O (2.08 g, 4.76 mmol, in 10 mL of
MeOH) were used in the ratio 1:4.4:4.2:2.1, and MeCN (10 mL),
followed by CH2Cl2 (20 mL), was added to get a clear solution. Very
light creamy, needle-like crystals were obtained in the first crop.
Yield: 1.75 g. The crystals of the second crop were again light red
and block-shaped. Yield: 0.38 g. A third crop of crystals was even
darker red. Yield: 0.083 g. Total yield: 93%. Anal. (crop I) Calcd
for C45H35As1Hg1O3S3 (mol wt 995.48): C, 54.30; H, 3.54. Found:
C, 54.00; H, 3.45. 13C NMR of anion11 (CH2Cl2): δ 200.0 (PhC(O)S),
141.7 (C1), 131.7 (C4), 128.8 (C2/6 or C3/5), 128.0 (C3/5 or C2/6).
factor calculations only. There is no shift in the final cycles.
A
summary of the crystallographic data is given in Table 1, and selected
positional parameters are given in Table 2. Complete crystallographic
data, positional and thermal parameters, complete bond distances and
angles, anisotropic thermal parameters, hydrogen atom coordinates,
selected torsion angles, selected weighted least-squares planes, selected
dihedral angles, and close contacts have been included in the Supporting
Information.
Results and Discussion
Synthesis. The thiobenzoate complexes [M(SOCPh)3]- (M
) Zn, Cd, Hg) were synthesized straightforwardly according
to eq 1. The SOCPh- anion was produced in situ by reaction
3SOCPh- + M2+ f [M(SOCPh)3]-
(1)
(12) XSCANS. Siemens Analytical X-Ray Instruments Inc., Madison, WI,
1990.
(13) SHELXTL Version 5 Reference Manual; Siemens Analytical X-Ray
Instruments Inc.: Madison, WI, 1994.
+
(11) Carbon-13 NMR spectrum of AsPh4 (CH2Cl2): 135.2 (C4), 133.2
(C2,6), 131.6 (C3,5), 120.6 (C1).

Chemistry of Thiobenzoates
Inorganic Chemistry, Vol. 35, No. 11, 1996 3091
Table 1. Crystallographic Data for (Ph4P)[Zn(SCOPh)3] (1), (Ph4As)[Cd(SCOPh)3] (2), and (Ph4P)[Hg(SCOPh)3] (3)
1
2
3
empirical formula
fw
C45H35P1O3S3Zn1
816.25
C45H35As1Cd1O3S3
907.23
C45H35Hg1P1O3S3
951.47
temp, °C
radiation; wavelength, Å
space group
unit cell dimens
23
Mo KR, 71073
P1h (No. 2)
P1h (No. 2)
P21/n (No. 14)
a, Å
b, Å
c, Å
10.819(2)
13.219(3)
15.951(3)
101.75(2)
97.92(1)
109.18(2)
2057.1(7)
2
10.741(2)
13.168(2)
15.809(2)
101.00(1)
97.65(1)
109.88(1)
2005.7(4)
2
13.202(2)
14.276(2)
21.108(2)
90
90.92(1)
90
3978.0(9)
4
...; 1.589
4.107
R, deg
â, deg
γ, deg
volume, Å3
Z
Fobsd, g cm-3; Fcalcd, g cm-3
abs coeff, mm-1
final R indices
[I > 2σ(I)]
1.37(5); 1.318
0.83
1.51(5); 1.502
1.559
R1a
0.0551
0.1186
0.0391
0.0820
0.0435
0.0913
wR2a
2
4
a R1 ) ∑(||Fo| - |Fc||)/|∑Fo|; wR2 ) [∑w(Fo - Fc2)2/∑wFo ]1/2
.
Table 2. Selected Atomic Coordinates (×104) and Equivalent
Table 3. Metal NMR Data for [M(SOCPh)3]- (M ) Cd or Hg)
Isotropic Displacement Parameters (Å2 × 103)
δCdc (∆V1/2
δHgd (∆V1/2
atom
x
y
z
U(eq)a
compound
solventa T/Kb (approx)/Hz) (approx)/Hz)
1, (Ph4P)[Zn(SCOPh)3]
(Ph4P)[Cd(SOCPh)3]
CH2Cl2 294
287 (8)
287 (7)
291 (∼20)
Zn(1)
S(1)
S(2)
S(3)
O(1)
O(2)
O(3)
C(1)
C(2)
C(3)
4407.1(6)
4434(1)
2645(2)
6578(2)
1992(4)
4135(4)
4897(4)
2827(5)
3187(6)
6043(5)
1981.1(5)
1341(1)
2015(1)
2568(1)
1366(5)
3684(3)
551(3)
1207(4)
3361(5)
1233(4)
2584.9(4)
1134(1)
3308(1)
3499(1)
980(3)
2812(2)
3244(2)
590(4)
64.0(2)
69.2(4)
77.5(4)
77.4(5)
114(2)
69(1)
73(1)
65(1)
65(1)
55(1)
(Ph4As)[Cd(SOCPh)3] CH2Cl2 295
(Ph4As)[Cd(SOCPh)3] MeCNe 294
(Ph4P)[Hg(SOCPh)3]
(Ph4As)[Hg(SOCPh)3] CH2Cl2 296
CH2Cl2 298
-749 (200)
-757 (190)
a Concentration ) 0.1 mol/L of solvent, except as noted. b (1 K.
c 113Cd, measured relative to external 0.1 M Cd(ClO4)2(aq). d 199Hg,
measured relative to external neat HgMe2. e Concentration 0.002 mol/L
of MeCN.
3194(3)
3636(3)
tetraphenyl-phosphonium and -arsonium salts ([EPh4][M-
(SOCPh)3] (M ) Zn, Cd, or Hg; E ) P or As).
Under the synthetic conditions used, we were not able to
isolate salts of [M(SOCPh)4]2- when PhCOS-:M2+ g 4. Such
mixtures yielded only [M(SOCPh)3]-.
2, (Ph4As)[Cd(SCOPh)3]
Cd(1)
S(1)
S(2)
S(3)
O(1)
O(2)
O(3)
C(1)
C(2)
C(3)
4390.0(4)
1939.2(3)
1337(1)
2100(1)
2554(1)
1309(5)
3770(3)
566(3)
1184(4)
3448(4)
1234(4)
2527.0(3)
58.0(2)
68.1(4)
72.1(4)
76.2(5)
103(2)
65(1)
64(1)
59(1)
55(1)
48(1)
4533(2)
2567(2)
6735(2)
2104(4)
4103(4)
4981(3)
2907(5)
3168(5)
6125(5)
979(1)
3329(1)
3515(1)
941(3)
2833(2)
3275(2)
498(4)
NMR Spectra. Metal NMR chemical shifts and line widths
are given in Table 3. The 113Cd NMR chemical shift of 291
ppm obtained for a dilute solution of [Cd(SOCPh)3]- in MeCN
is in the region (e292 ppm) anticipated3 from dilution data for
the anion (Na[Cd{SOCPh)3]2)-. This is consistent with the
suggestion3 that (Na[Cd{SOCPh)3]2)- undergoes dissociation
in solution, releasing [Cd(SOCPh)3]-.
The metal resonances of [M(SOCPh)3]- (M ) Cd or Hg)
are significantly more shielded than those obtained for [M(SR)3]-
(Table 4), even though the thiobenzoates and thiolates all have
planar MS3 skeletons. Almost certainly this can be attributed
to the effect of weak interactions with the oxygen atoms in
[M(SOCPh)3]- (see below), as we have argued previously,3,14
but further study is desirable.
3215(3)
3660(3)
3, (Ph4P)[Hg(SCOPh)3]
Hg(1)
S(1)
S(2)
S(3)
O(1)
O(2)
O(3)
C(1)
C(2)
C(3)
378.4(2)
-784(2)
1583(2)
90(2)
1962.0(2)
2369(2)
712(2)
3309(2)
950(4)
2233(4)
1923(4)
1582(5)
1386(6)
2742(7)
1120.0(2)
1983(1)
1016(1)
357(1)
2547(2)
860(3)
134(3)
2601(3)
889(4)
60.6(1)
58.7(6)
73.2(7)
84.2(8)
63(2)
79(2)
85(2)
47(2)
57(2)
60(2)
120(4)
2653(5)
-1130(5)
-491(5)
2657(6)
-931(6)
23(3)
A noteworthy feature of the 13C NMR spectra of
[M(SOCPh)3]- is the irregular variation of the δC(PhCOS) (and
hence the corresponding ∆δC ) δC(complexed) - δC(free)17)
with M: the values are 207.7 (-5.1), 206.8 (-6.0) and 199.7
a U(eq) is defined as one-third of the trace of the orthogonalized Uij
tensor.
of PhCOSH with Et3N rather than Na, to avoid the incorporation
of Na+ into the product that was found earlier3 for M ) Cd. A
peculiarity of the reaction with M ) Hg (as HgCl2) is that the
solution of SOCPh- must be added close to the surface of the
Hg(II)-containing solution to avoid formation of a black
substance, presumed to be â-HgS. An analogous situation was
observed14 in the synthesis of thiobenzoates of Pb(II) and Bi-
(III). The complex anions were isolated analytically pure as
(14) Burnett, T. R.; Dean, P. A. W.; Vittal, J. J. Can. J. Chem. 1994, 72,
1127.
(15) Han, May; Peersen, O. B.; Bryson, J. W.; O’Halloran, T. V.; Smith,
S. O. Inorg. Chem. 1995, 34, 1187.
(16) Natan, M. J.; Millikan, C.; Wright, J. G.; O’Halloran, T. V. J. Am.
Chem. Soc. 1990, 112, 3255.
(17) C-13 NMR spectrum of PhCOS- (in a solution in CH2Cl2 where NMe3:
PhCOSH ) 2:1): 212.8 (PhCOS) 144.2 (C1), 130.3 (C4), 128.5
(C2/6 or 3/5), 127.5 (C3/5 or 2/6).

3092 Inorganic Chemistry, Vol. 35, No. 11, 1996
Vittal and Dean
ref
Table 4. Metal NMR Data for [M(SR)3]- (M ) Cd or Hg)a
b
c
compound
δCd
δHg
(Ph4P)[Cd(S-2,4,6-Pri3C6H2)3]
(Me4N)[Hg(SPri)3]
577 (in CDCl3 or DMF);d 668e (solid state)
4, 5
15
16
5, 16
5
-79 (solid state)
(Et4N)[Hg(SBut)3]
-157 (in DMSO); -158 (solid state)
(Bun N)[Hg(SPh)3]
-354 (in DMSO); -341e (solid state)
-247 (solid state, form 1); -276 (solid state, form 2)
4
(Ph4P)[Hg(S-2,3,4,5-Me4C6H)3]
a At ambient probe temperature. b 113Cd relative to external 0.1 M Cd(ClO4)2(aq). c 199Hg relative to external HgMe2. d Reference 4. e Reference
5.
Table 5. Selected Bond Distances (Å), Angles (deg), and
Deviations (Å) from the S3 and O3 Planes in the Anions of 1, 2, and
3
1
2
3
Bond Distances
M(1)-S(1)
M(1)-S(2)
M(1)-S(3)
M(1)-O(1)
M(1)-O(2)
M(1)-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)
2.304(2)
2.368(2)
2.376(2)
3.156(4)
2.328(4)
2.505(4)
1.769(5)
1.738(6)
1.737(5)
1.215(6)
1.263(6)
1.251(6)
1.525(7)
1.510(7)
1.508(6)
2.453(2)
2.514(2)
2.545(2)
3.019(4)
2.490(4)
2.557(3)
1.736(6)
1.728(5)
1.712(5)
1.214(6)
1.237(6)
1.224(5)
1.495(7)
1.483(7)
1.506(7)
2.470(2)
2.402(2)
2.533(2)
3.364(5)
3.086(6)
2.858(6)
1.761(7)
1.737(8)
1.714(9)
1.216(8)
1.211(9)
1.222(9)
1.497(10)
1.513(10)
1.523(11)
Figure 1. View of the [Zn(SOCPh)3]- anion in 1, showing the
numbering scheme and 50% probability thermal ellipsoids. The same
numbering scheme is used for the isostructural anion in 2.
Bond Angles
S(1)-M(1)-S(2)
S(1)-M(1)-S(3)
S(2)-M(1)-S(3)
S(1)-M(1)-O(1)
S(2)-M(1)-O(1)
S(3)-M(1)-O(1)
S(1)-M(1)-O(2)
S(2)-M(1)-O(2)
S(3)-M(1)-O(2)
S(1)-M(1)-O(3)
S(2)-M(1)-O(3)
S(3)-M(1)-O(3)
O(2)-M(1)-O(1)
O(3)-M(1)-O(1)
O(3)-M(1)-O(2)
C(1)-S(1)-M(1)
C(2)-S(2)-M(1)
C(3)-S(3)-M(1)
C(1)-O(1)-M(1)
C(2)-O(2)-M(1)
C(3)-O(3)-M(1)
O(1)-C(1)-C(11)
O(1)-C(1)-S(1)
C(11)-C(1)-S(1)
O(2)-C(2)-C(21)
O(2)-C(2)-S(2)
C(21)-C(2)-S(2)
O(3)-C(3)-C(31)
O(3)-C(3)-S(3)
C(31)-C(3)-S(3)
132.50(6)
110.96(6)
116.32(6)
55.00(9)
78.60(9)
164.10(9)
109.92(10)
67.58(10)
98.97(10)
101.95(10)
94.33(9)
64.27(9)
81.17(13)
122.68(13)
147.79(12)
101.9(2)
80.2(2)
136.31(5)
108.50(6)
115.18(6)
55.33(9)
81.15(9)
162.86(9)
110.68(9)
62.65(9)
99.19(10)
105.12(9)
96.71(9)
60.38(8)
83.39(14)
125.61(13)
143.15(12)
96.9(2)
131.48(7)
101.59(8)
126.79(9)
50.76(10)
80.78(11)
151.52(11)
136.04(13)
55.20(13)
85.91(13)
96.2(2)
111.94(14)
57.02(13)
109.05(14)
124.4(2)
122.8(2)
105.3(3)
98.4(3)
90.7(3)
80.9(4)
82.4(5)
88.4(5)
120.9(7)
122.8(6)
116.2(5)
121.0(8)
123.9(7)
115.0(6)
118.8(8)
122.9(7)
118.3(7)
Figure 2. View of the [Hg(SOCPh)3]- anion in 3, showing the
numbering scheme and 50% probability thermal ellipsoids.
82.1(2)
84.2(2)
84.9(2)
80.2(3)
92.0(3)
85.8(3)
93.5(3)
+
ppm (-13.1 ppm for M ) Cd, Zn, and Hg as the PPh4 salts.
90.8(3)
94.5(3)
It may be significant Zn appears to be intermediate between
Cd and Hg in the percentage of the total bonding interaction
that is provided by sulfur also (see below). Irregular variations
have been observed for other nuclei attached directly and
indirectly to the group 12 elements, e.g. 77Se for both SeR and
120.2(5)
122.8(4)
117.0(4)
120.0(5)
120.2(4)
119.8(4)
120.7(5)
120.0(4)
119.2(4)
120.6(5)
121.8(4)
117.6(4)
119.5(5)
121.8(4)
118.7(4)
119.0(4)
121.0(4)
120.1(4)
Seâ in [M(Se4)2]2- 18,19
[M(Te4)2]2- 20
;
125Te for both TeR and Teâ in
.
Structures of [M(SOCPh)3]- (M ) Zn-Hg). The crystal
structures of 1-3 each consist of discrete cations and anions.
The compounds 1 and 2 are isomorphous and isostructural. The
structures of the cations in 1-3 are unexceptional and will not
be discussed further. The structures of the anions in 1 and 3
are shown in Figures 1 and 2, while selected distances, angles
and deviations of M from the S3 and O3 planes are given in
Table 5.
Deviations of M from S3 Planes
-0.0641 -0.0063
-0.0527
Deviations of M from O3 Planes
0.3785 0.3917
0.3466
In each anion, the metal atom is bonded to three PhCOS-
ligands. Within each, the metal atom lies in the plane of the
three sulfur atoms. Each metal atom is further bonded weakly
to oxygen atoms. In the PhCOS- ligands, COS planes are
twisted from the planes of the associated phenyl rings. The
dihedral angles range from 7.0 to 19.6°.
(18) Ansari, M. A.; Mahler, C. H.; Chorghade, G. S.; Lu, Y.-J.; Ibers, J.
A. Inorg. Chem. 1990, 29, 3832.
(19) Cusick, J. M. Ph.D. Thesis, University of New South Wales, 1993.
(20) Bollinger, J. C.; Roof, L. C.; Smith, D. M.; McConnachie, J. M.; Ibers,
J. A. Inorg. Chem. 1995, 34, 1430.

Chemistry of Thiobenzoates
Inorganic Chemistry, Vol. 35, No. 11, 1996 3093
Table 6. Bond Valencesa of Zn-Hg in Some Thiobenzoate
The Zn-S distances in 1 are range from 2.304 to 2.376 Å
and thus are longer than the 2.278 Å reported21 for [Zn-
(SCOPh)2(H2O)2], the 2.217-2.243 Å observed7 in trigonal
planar [Zn(S-2,3,5,6-Me4C6H)3]- and the 2.184 and 2.203Å
found8 for the terminal Zn-S bonds of the trigonal planar ZnS3
kernels in dimeric [Zn(S-2,4,6-But3C6H2)2]2. The three Zn-O
distances, 3.156, 2.328, and 2.505 Å in 1 are significantly
different from each other and all shorter than that of 3.293 Å
found21 for the analogous interactions in [Zn(SCOPh)2(H2O)2].
The Zn(1)-O(2) and Zn(1)-O(3) distances are less than the
sum of the van der Waals radii for Zn and O (2.9 Å22).
Including these two Zn-O interactions in the coordination
sphere, the geometry of zinc may be described as a trigonal
bipyramid. The C(1) and O(1) atoms are approximately in the
ZnS3 plane, between S(1) and S(2). The location of O(1) is
reflected in the relatively large value of the angle S(1)-Zn-
(1)-S(2) (132.5°) and the relatively small value of the angle
O(1)-Zn(1)-S(2) (78.6°). The Zn atom is only 0.38 Å out of
the O3 plane, the sum of the O-Zn-O angles being 351.6°.
The dihedral angle between the S3 and O3 planes is 75.2°.
The structure of 2 is very similar to that of 1 as noted earlier.
The Cd-S distances (2.453-2.545 Å; mean 2.504 Å) observed
in 2 are comparable to those found3 in (Me4N)[Na(M-
{SCOPh}3)2] (2.485-2.521 Å; mean 2.50 Å) but longer than
the Cd-S distances measured for the trigonal planar kernels of
[Cd(S-i-Pr3C6H2-2,4,6)3]- (2.419-2.428 Å4) and [Cd(S-2,4,6-
But3C6H2)2]2 (2.377 Å for the terminal bonds6). Paralleling 1,
C(1) and O(1) are approximately in the CdS3 plane between
S(1) and S(2). Thus the angle O(1)-Cd(1)-S(2) (81.2°) is
relatively small, while the angle S(1)-Cd(1)-S(2) is opened
up (136.3°). The sum of the O-Cd-O angles is 352.1°, with
the Cd displaced from the O3 plane by 0.39 Å. The dihedral
angles between the S3 and O3 planes is 71.9°.
Complexesb
tot. bond valence,
% of
% of
compound
Vi, of M
M-S M-O
1
2
3
1.838
2.182
2.129
2.080
82.6
80.5
92.3
85.1
17.4
19.5
7.7
(Me4N)[Na(Cd{SOCPh}3)2]
14.9
a See ref 23. b Based on bond distances given in this paper and ref
3.
between S(2) and S(3), closer to the S3 plane than in 1 or 2.
This leads to a comparatively large S(2)-Hg(1)-S(3) angle
(126.8°). Also noteworthy is the unexpected trend observed
for the M-S distances, Zn < Hg < Cd. We believe that this
reflects different extents of interaction with oxygen (see below).
In the compounds 1, 2, and 3, trigonal planar geometry of
the MS3 kernel is maintained regardless of the orientation of
the COPh groups. Probably the steric bulk of the PhCOS-
ligands promotes a planarity that is unaffected by the relatively
weak M‚‚‚O interaction(s). The contributions of the carbonyl
oxygen atoms to the total bonding in [M(SCOPh)3]- may be
estimated using the bond-valence approach.24 The results are
shown in Table 6. They suggest that the interaction with oxygen
contributes most in the case of 2 and that this contribution is
reduced by competition with Na+ in [Na(Cd{SOCPh}3)2]-, as
expected. Also noteworthy is the relatively small contribution
that oxygen makes in 3. This suggests that [Hg(SOCPh)3]-
should be an even better oxygen-donor metalloligand than
[Cd(SOCPh)3]-.
Acknowledgment. This work was made possible by an
Individual Research Grant to P.A.W.D. from the Natural
Sciences and Engineering Research Council of Canada (NSERC)
and by an Equipment Grant to this department from the NSERC
that allowed the purchase of the diffractometer for the Depart-
mental X-Ray Structure Service Facility. We are grateful to
Susan England of this department for expert assistance with
NMR spectrometers.
The Hg-S distances of 2.402, 2.470, and 2.533 Å oberved in
3 are marginally larger on average than those reported4,5,9 for
various [Hg(SAr)3]-. The Hg‚‚‚O distances are in the range
2.858-3.364 Å. The Hg(1)-O(3) distance, 2.858 Å is smaller
than the sum of the van der Waals radii of Hg and O (3.0 Å22,23
)
indicating a weak interaction between Hg and this O atom. If
O(3) is included in the coordination sphere of Hg, [Hg(SOCPh)3]-
has a trigonal pyramidal HgS3O kernel.
The structural difference between the anion in 3 and those
in 1 or 2 stems from the orientation of S(2), S(3), O(2), and
O(3). The carbonyl group C(2)-O(2) in 3 occupies the space
Supporting Information Available: Tables of crystallographic data
for 1, 2, and 3, positional and thermal parameters, complete bond
distances and angles, anisotropic thermal parameters, calculated
hydrogen atom coordinates, selected torsion angles, selected weighted
least-squares planes, selected dihedral angles, and close contacts in 1,
2 and 3, and a figure showing a view of the [Cd(SOCPh)3]- anion in
2 (37 pages). Ordering information is given on any current masthead
page.
(21) Bonamico, M., Dessy, G., Fares, V. and Scaramuzza, L. J. Chem.
Soc. Dalton Trans. 1976, 67.
(22) Bondi, A. J. Phys. Chem. 1964, 68, 441.
IC9514298
(23) There is disagreement over the van der Waals radius of Hg: Canty,
A. J.; Deacon, G. B. Inorg. Chim. Acta 1980, 45, L225.
(24) Brown, I. D.; Altermatt, D. Acta Crystallogr., Sect. B 1985, B41,244.