Synthesis and Stereochemistry of Homoleptic Transition Metal Thiobenzoate Complexes, (Ph4P)[M(SC{O}Ph)3] (M = Mn, Co, and Ni)

Full text of DOI:10.1021/ic980394j

Inorg. Chem. 1998, 37, 6939-6941
6939
Synthesis and Stereochemistry of Homoleptic
Transition Metal Thiobenzoate Complexes,
(Ph4P)[M(SC{O}Ph)3] (M ) Mn, Co, and Ni)†
Rema Devy and Jagadese J. Vittal*
Department of Chemistry, National University of Singapore,
Singapore 119 260
Philip A. W. Dean*
Department of Chemistry, The University of Western
Ontario, London, Ontario, Canada N6A 5B7
ReceiVed April 7, 1998
Figure 1. A ball-and-stick diagram of the disordered Ph4P+ in 1.
Introduction
Lut ) 3,5-dimethylpyridine) as precursors to metal sulfide
materials.9 Further, indium and tin thiobenzoate complexes have
been reported.10 However, apart from simple neutral metal-
thiobenzoates,11 to our knowledge no other homoleptic transition
metal(II) thiobenzoato complexes have been reported. The
transition metal(II) ions are expected to exhibit variable
coordination numbers, and it was thought interesting to syn-
thesize thiobenzoate complexes and study their stereochemical
features. Reported here are the syntheses and structural proper-
ties of the first homoleptic thiobenzoato complexes of Mn(II),
Co(II), and Ni(II).
The chemistry of metal-thiocarboxylates has not been ex-
plored extensively, as compared to that of metal thiolates.1
However, the RC{O}S- anions constitute an interesting class
of ligands having a soft sulfur donor site and a hard oxygen
donor site. Recently we have begun a systematic exploration
of the ligand chemistry of the thiobenzoate anion, PhC{O}S-.
The ability of the ligand to bind to both hard and soft metals
has been demonstrated in the structure of {Na[Cd(SC{O}Ph)3]2}-
anion in which the relatively soft Cd(II) ion is bonded strongly
to the sulfur atoms while the hard Na (I) ion is attached to the
oxygen atoms.2 All three divalent group 12 elements form anions
[M(SC{O}Ph)3]-, in which the metal atoms are surrounded by
three sulfur atoms in a trigonal planar fashion3, with much
weaker M‚‚‚O bonding. This trigonal planar geometry appears
to be independent of the nature of counterions and hydrogen
bonding effect.4,5 Very lately, we have also found a different,
trigonal pyramidal stereochemistry around Cd in two of the three
crystallographically different anions in rhombohedral (Ph4P)-
[Cd(SC{O}Ph)3].6 In the case of triligated Sn(II) and Pb(II)
complexes, a trigonal pyramidal geometry was observed with
weak or no interactions between the O atoms of carbonyl groups
and the central metal ions.7,8 These structural differences are
presumably controlled by the nature of the metal ions, most
obviously by the presence of a stereochemically active lone pair
in the Sn(II) and Pb(II) complexes. Recently, Hampden-Smith
et al. have prepared group 12 metal thiocarboxylates of the type
[M(SC{O}R)2Lut2] (where M ) Zn, Cd, R ) Me, C(CH3)3,
Results and Discussion
Syntheses. The anions [M(SC{O}Ph)3]- (M ) Mn, Co, Ni)
were synthesized from an appropriate metal salt and Et3NH+
PhC{O}S- (produced in situ from PhC{O}SH and Et3N), as
given by eq 1.
M
2+ + 3 PhC{O}S- f [M(SC{O}Ph)3]-
(1)
These monoanions were isolated as the Ph4P+ salts. Under
our experimental conditions, no tetrakis(thiobenzoato) or higher
complexes were obtained.
Structures of (Ph4P)[M(SC{O}Ph)3] (M ) Mn, (1), Co,
(2), Ni, (3)). The crystal and molecular structures were
determined by single-crystal X-ray diffraction techniques. The
crystal structures of 1-3 consist of discrete cations and anions.
All three compounds crystallized in the same trigonal space
group R3. Both anions and cations have crystallographically
imposed C3 symmetry. As a consequence, one phenyl ring (C21-
C26) of the Ph4P+ was disordered (Figure 1). Disorder of Ph4P+
is uncommon since these cations are usually locked into place
by specific cation-cation interactions.12
* To whom correspondence may be addressed.
† Taken in part from the Honors Research Thesis of Rema Devy, National
University of Singapore, 1998.
(1) (a) Dance, I. G. Polyhedron 1986, 5, 1037. (b) Dilworth, J. R.; Hu, J.
AdV. Inorg. Chem. 1994, 40, 411. (c) Blower, P. J.; Dilworth, J. R.
Coord. Chem. ReV., 1987, 76, 121. (d) Krebs, B.; Henkel, G. Angew.
Chem., Int. Ed. Engl., 1991, 30, 769. (e) Stephan, D. W.; Nadasdi, T.
T. Coord. Chem. ReV., 1996, 147, 147. (f) Dance, I. G.; Fisher, K.;
Lee, G. In Metallothioneins. Synthesis, Structure and Properties of
Metallothioneins, Phytochelatins and Metal-Thiolate Complexes;
Stillman, M. J., Shaw, C. F., III, Suzuki, K. T. Eds.; VCH Publishers:
Germany, 1992; p 284.
(2) Vittal, J. J.; Dean, P. A. W. Inorg. Chem. 1993, 32, 791.
(3) Vittal, J. J.; Dean, P. A. W. Inorg. Chem. 1996, 35, 3089.
(4) Vittal, J. J.; Dean, P. A. W. Acta Crystallogr. 1997, C53, 409.
(5) Vittal, J. J.; Dean, P. A. W. Acta Crystallogr. 1998, C54, 319.
(6) Dean, P. A. W.; Vittal, J. J.; Craig, D. C.; Scudder, M. L. Inorg. Chem.
1998, 37, 1661.
In the anions, the metal atoms are situated on the C3 axis,
and the three PhC{O}S- ligands are related by 3-fold rotational
symmetry. The structure of a representative anion in 3 is shown
in Figure 2. Selected bond distances angles and interplanar
(9) Nyman, M. D.; Hampden-Smith, M. J.; Duesler, E. N. Inorg. Chem.
1997, 36, 2218.
(10) Singh, P.; Bhattacharya, S.; Gupta, V. D.; Noth, H. Chem. Ber. 1996,
129, 1093.
(7) Vittal, J. J.; Dean, P. A. W. Acta Crystallogr. 1996, C52, 1180.
(8) Burnett, T. R.; Dean, P. A. W.; Vittal, J. J. Canadian J. Chem. 1994,
72, 1127.
(11) Savant, V. V.; Gopalakrishnan, J.; Patel, C. C. Inorg. Chem. 1970, 9,
748.
(12) Dance, I. G.; Scudder, M. L. J. Chem. Soc., Dalton Trans. 1996, 3755.
10.1021/ic980394j CCC: $15.00 © 1998 American Chemical Society
Published on Web 12/01/1998

6940 Inorganic Chemistry, Vol. 37, No. 26, 1998
Notes
for an ideal trigonal prism. In the PhC{O}S- ligand, the COS
planes are twisted from the planes of the associated phenyl
groups.
The anion is chiral. It is interesting to note that in all the
three structures, the anions have the Λ-form, as confirmed by
refining their Flack parameters. The identical chiralities probably
result from serendipitous crystal picking. The bulk compounds
did not show any optical activity in CH2Cl2 solution.
X-ray powder diffractometry of 1, 2, and 3 gave patterns
consistent with expectation based on the crystal structure data.
Within experimental errors, it may be concluded that the bulk
compositions are consistent with the determined structures, and
that the bulk contains anions with the fac geometry only.
Experimental Section
All the materials used in the syntheses were obtained commercially
and used as received except that solvents were dried over 3 Å molecular
sieves. All the preparations were carried out under N2. X-ray powder
patterns were obtained using a D5005 Siemens X-ray Diffractometer.
Magnetic moments were determined with the aid of a Johnson Mathey
Magnetic Susceptibility Balance. Optical activities in solution were
determined using a Perkin-Elmer 341 polarimeter. The Microanalytial
laboratory at NUS performed microanalyses.
(Ph4P)[Mn(SC{O}Ph)3] (1). Triethylamine (4.20 mL, 0.03 mol) in
methanol (20.0 mL) was added dropwise to a solution of thiobenzoic
acid (4.516 g, 0.03 mol) in methanol (30.0 mL). MnCl2‚4H2O (1.926
g, 0.01 mol) in methanol (10.0 mL) was then added. The solution turned
from yellow to orange-yellow. Ph4PBr (4.082 g, 0.01 mol) in methanol
(20.0 mL) was added dropwise from a syringe. A yellow precipitate
was observed to have formed halfway through the addition. Dichloro-
methane (90.0 mL) and ethyl acetate (5.0 mL) were added together
with heating to dissolve the precipitate. The solution was placed in the
refrigerator overnight for crystallization to occur. Orange crystals were
obtained. The mother liquor was removed, and the crystals were then
dried under nitrogen. (Yield 2.7 g, 34.6%). Anal. Calcd for C45H35O3S3-
MnP (mol wt 805.82): C, 67.07; H, 4.38; S, 11.94. Found: C, 66.30;
H, 4.44; S, 12.26. Magnetic moments, 5.99 µB.
(Ph4P)[Co(SC{O}Ph)3] (2). This preparation was essentially the
same as that of 1. However, the amounts of starting materials were as
follows: PhC{O}SH, 2.0 mL, 0.0153 mol; Et3N, 2.13 mL, 0.0153 mol;
Co(NO3)2‚6H2O, 1.483 g, 0.005 mol; PPh4Br, 2.145 g, 0.005 mol. The
yield of the greenish-brown precipitate was 2.490 g, 60.2%. Anal. Calcd
for C45H35O3S3CoP (mol wt 809.91) C, 66.74; H, 4.36; S, 11.88.
Found: C, 65.87; H, 4.20; S, 12.10. Magnetic moments, 4.67 µB.
(Ph4P)[Ni(SC{O}Ph)3] (3). The synthesis was similar to that of 2.
The materials used were as follows: PhC{O}SH, 0.693 g, 0.0045 mol;
Et3N, 0.63 mL, 0.0045 mol; NiCl2‚6H2O, 0.215 g, 0.0009 mol; PPh4-
Br, 0.378 g, 0.0009 mol. The yield for the yellowish-brown precipitate
obtained was 0.663 g, 90.4%. Anal. Calcd for C45H35O3S3NiP (mol wt
809.59): C, 66.76; H, 4.36; S, 11.88. Found: C, 66.25; H, 4.16; S,
11.70. Magnetic moments, 2.96 µB.
Single crystals of 1 were obtained during synthesis whereas for 2
and 3, they were obtained by the diffusion method from a CH2Cl2
solution and ethyl acetate at 5 °C and room temperature, respectively.
X-ray Structure Determinations. The diffraction experiments were
carried out on a Siemens SMART CCD three-circle diffractometer with
a Mo KR sealed tube at 23 °C. The softwares used were as follows:
SMART13 for collecting frames of data, indexing reflection, and
determination of lattice parameters; SAINT13 for integration of intensity
of reflections and scaling; SADABS14 for absorption correction; and
SHELXTL15 for space group determination, structure solution, and least-
squares refinements on F2. In the trigonal crystal system, between
Figure 2. An ORTEP diagram of the anion [Ni(SC{O}Ph)3]- with
50% probability thermal ellipsoids and the numbering scheme. The
hydrogen atoms are omitted for clarity.
Table 1. Selected Molecular Geometric Parameters (distances, Å,
and angles, deg)
Mn
Bond distances
Co
Ni
M-S
M-O
S-C
O-C
2.576(2)
2.214(4)
1.702(6)
1.264(6)
2.468(2)
2.139(3)
1.706(5)
1.241(5)
2.419(1)
2.100(2)
1.705(4)
1.260(4)
Bond angles
104.41(6) 103.54(6) 102.57(4)
S-M-S
O-M-O
O-C-S
O-M-S
M-S-C
M-O-C
95.6(1)
120.0(4)
64.6(1)
75.7(2)
98.9(3)
95.8(1)
119.3(4)
66.91(8)
75.2(2)
98.0(3)
85.83(9)
13.4(3)
95.96(9)
118.1(3)
68.35(7)
75.5(2)
97.5(2)
86.74(7)
13.2(2)
dihedral angle between MSOC planes 83.28(9)
dihedral angle between phenyl ring
and COSM plane
14.1(3)
distance of M from S3 plane
distance of M from O3 plane
1.054(2)
1.146(4)
1.039(2)
1.103(3)
1.050(1)
1.079(2)
angles are given in Table 1. The sulfur and oxygen atoms from
each thiobenzoate ligand are bonded to the central metal atom
to provide a distorted octahedral coordination geometry. For
MS3O3 kernel two types of geometry are possible namely, fac
and mer. The anions in the present study are found to occur as
the fac geometry. The geometry around the metal is somewhat
similar to that observed6 in one of the crystallographically
independent anions of rhombohedral (Ph4P)[Cd(SC{O}Ph)3].
However, in this anion, which has the C3 symmetry, the Cd-S
bond distances are shorter than the Cd-O distances. The
geometry of the anions in 1-3 is quite different from that found3
in (Ph4P)[Zn(S{O}CPh)3], where the anion has a near-planar
ZnS3 kernel and two long Zn‚‚‚O interations. The M-O bond
lengths and the M-S bond lengths were found to increase in
the same order as the size of the metal ions, which are high-
spin for M ) Mn and Co (see Experimental Section), i.e., Mn(II)
> Co(II) > Ni(II). The S-M-S angles vary in the same order,
while the O-M-O angles show the reverse order, although in
this case the differences are not significant. In the distorted
octahedral geometry of the anion, the metal ion is sandwiched
between the O3 and the S3 planes. It may be noted that the
distances of M from the O3 and the S3 planes do not differ
significantly. The twist angles between the S3 faces and the O3
faces are 34(1), 39(1), and 39(1)° for 1, 2, and 3, respectively,
partway between 60° expected for an ideal octahedron and 0°
(13) SMART & SAINT Software Reference Manuals, Version 4.0, Siemens
Energy & Automation, Inc., Analytical Instrumentation, Madison, WI,
1996.
(14) Sheldrick, G. M. SADABS a software for empirical absorption
correction, University of Gottingen, Gottingen, Germany, 1996.
(15) SHELXTL Reference Manual, Version 5.03, Siemens Energy &
Automation, Inc., Analytical Instrumentation, Madison, WI, 1996.

Notes
Inorganic Chemistry, Vol. 37, No. 26, 1998 6941
Table 2. Summary of Crystallographic Data for 1-3
consequence, this phenyl ring is crystallographically disordered. The
disordered rings were resolved successfully and modeled, and con-
straints were applied to keep the ideal symmetry of the phenyl ring. A
riding model was used to place the hydrogen atoms in their idealized
positions. The crystal of 2 was found to be twinned by merohedry.
The twin matrix 010, 100, 00-1 was used, and the batch scale factor
for this twin matrix was refined to 0.445(2). A brief summary of the
crystallographic data is given in Table 2.
1
2
3
chemical formula C45H35MnO3PS3 C45H35CoO3PS3 C45H35NiO3PS3
formula weight
805.82
809.81
R3 (no. 146)
20
0.71073
13.2775(2)
19.8742(5)
3034.3(1)
3
1.330
6.58
0.0399
0.0795
809.59
space group
T, °C
λ, Å
a, Å
13.2996(5)
19.934(1)
3053.5(2)
13.2343(3)
19.7741(2)
2999.36(7)
c, Å
V, Å3
Z
Acknowledgment. We thank Ms. K.S. Anjali for technical
assistance to record X-ray powder patterns. J.J.V. thanks
National University of Singapore for the research grant (Grant
No. RP970618), and P.A.W.D. thanks the Natural Sciences and
Engineering Research Council of Canada for financial support.
F
calc, g cm-3
1.315
5.60
0.0532
1.345
7.21
0.0462
0.0961
µ, cm-1
R1 [I g 2σ(I)]a
wR2 [I g 2σ(I)]b 0.1315
a R1 ) (||Fo| - |Fc||)/(|Fo|). b wR2 ) [(w(Fo - Fc2)/(wFo ]1/2
.
2
4
Supporting Information Available: Observed and simulated X-ray
powder patterns for complexes (1, 2 and 3) have been deposited (6
pages). X-ray crystallographic files in CIF format for complexes 1, 2
and 3 are available on the Internet only. Ordering and access information
is given on any current masthead page.
centric- and noncentric space groups, the choice of the chiral space
group R3 was based on E2 statistics. Successful solution and refinement
of the structure confirmed the correctness of the choice. For Z ) 3,
there is a crystallographically imposed C3 symmetry present in the
Ph4P+ cation, and the P and C21 of Ph4P+ are on the C3-axis. As a
IC980394J