Heavy alkali metal arenedithiocarboxylates: A facile synthesis, dimeric structure, and nonbonding interaction between the metals and aromatic ring carbons

Article abstract of DOI:10.1021/ic9808089

Dithiocarboxylic acids and their trimethylsilyl esters were found to readily react with potassium, rubidium, and cesium fluorides to give the corresponding alkali metal dithiocarboxylates 3-5 in moderate to good yields. A series of tetramethylammonium dithiocarboxylates 8 have been prepared in good yields by the reaction of sodium dithiocarboxylates 7 with tetramethylammonium chloride. The structures of potassium (3b), rubidium (4g), cesium (5f), and tetramethylammonium 4-methylbenzenecarbodithioates (8e) and tetramethylammonium 2-methoxybenzenecarbodithioate (8f) were characterized crystallographically. These heavier alkali metal salts (3b, 4g, 5f) have a dimeric structure [(RCSSM)₂, M = K, Rb, Cs] in which the two dithiocarboxylate groups are chelated to the metal cations which are located on the upper and lower sides of the plane involving the two opposing dithiocarboxylate groups. The K⁺ cations interact with the tolyl fragment of a neighboring molecule, while the Rb⁺ and Cs⁺ cations interact with two neighboring tolyl fragments, in which the ipso and ortho carbons are positioned close to the metals. The interaction number of the metals with surrounding atoms is 8 for K⁺ and Rb⁺ and 12 for Cs⁺. The C-S distances of the dithiocarboxylate group are different for the potassium salt 3b. In contrast, those of the rubidium salt 4g and cesium salt 5f are equal. Similarly, the chelating sulfur-metal bond distances of 3b are different, while those of 4g and 5f are almost equal. The dihedral angles of the phenyl ring and dithiocarboxylate plane increase in the order of the K, Rb, and Cs salts. The structural analysis of sodium 4-methylbenzenecarbodithioate (7g) revealed the presence of 4-CH₃C₆H₄CS₂Na_0.36. In contrast, the tetramethylammonium salts 8 are monomeric where the cation moieties are located out of the dithiocarboxylate plane. The potassium 3, rubidium 4, and cesium dithiocarboxylates 5 readily reacted with methyl iodide or triorganotin chlorides at room temperature to give the corresponding methyl 9 and triorganotin dithioesters 10 in good yields. At 0 °C, the reactivity of the rubidium 4 and cesium salts 5 to methyl iodides decreases dramatically compared with those of the sodium salts 7 and potassium salts 3.

Full text of DOI:10.1021/ic9808089

496
Inorg. Chem. 1999, 38, 496-506
Heavy Alkali Metal Arenedithiocarboxylates: A Facile Synthesis, Dimeric Structure, and
Nonbonding Interaction between the Metals and Aromatic Ring Carbons
Shinzi Kato,* Nobuyuki Kitaoka, Osamu Niyomura, Yuka Kitoh, Takahiro Kanda, and
Masahiro Ebihara*
Department of Chemistry, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan
ReceiVed July 15, 1998
Dithiocarboxylic acids and their trimethylsilyl esters were found to readily react with potassium, rubidium, and
cesium fluorides to give the corresponding alkali metal dithiocarboxylates 3-5 in moderate to good yields. A
series of tetramethylammonium dithiocarboxylates 8 have been prepared in good yields by the reaction of sodium
dithiocarboxylates 7 with tetramethylammonium chloride. The structures of potassium (3b), rubidium (4g), cesium
(5f), and tetramethylammonium 4-methylbenzenecarbodithioates (8e) and tetramethylammonium 2-methoxyben-
zenecarbodithioate (8f) were characterized crystallographically. These heavier alkali metal salts (3b, 4g, 5f) have
a dimeric structure [(RCSSM)2, M ) K, Rb, Cs] in which the two dithiocarboxylate groups are chelated to the
metal cations which are located on the upper and lower sides of the plane involving the two opposing
dithiocarboxylate groups. The K+ cations interact with the tolyl fragment of a neighboring molecule, while the
Rb+ and Cs+ cations interact with two neighboring tolyl fragments, in which the ipso and ortho carbons are
positioned close to the metals. The interaction number of the metals with surrounding atoms is 8 for K+ and Rb+
and 12 for Cs+. The C-S distances of the dithiocarboxylate group are different for the potassium salt 3b. In
contrast, those of the rubidium salt 4g and cesium salt 5f are equal. Similarly, the chelating sulfur-metal bond
distances of 3b are different, while those of 4g and 5f are almost equal. The dihedral angles of the phenyl ring
and dithiocarboxylate plane increase in the order of the K, Rb, and Cs salts. The structural analysis of sodium
4-methylbenzenecarbodithioate (7g) revealed the presence of 4-CH3C6H4CS2Na0.36. In contrast, the tetramethyl-
ammonium salts 8 are monomeric where the cation moieties are located out of the dithiocarboxylate plane. The
potassium 3, rubidium 4, and cesium dithiocarboxylates 5 readily reacted with methyl iodide or triorganotin
chlorides at room temperature to give the corresponding methyl 9 and triorganotin dithioesters 10 in good yields.
At 0 °C, the reactivity of the rubidium 4 and cesium salts 5 to methyl iodides decreases dramatically compared
with those of the sodium salts 7 and potassium salts 3.
Introduction
Scheme 1
Alkali metal carboxylates and chalcogenocarboxylates in
which one or two oxygen atoms in the carboxyl group were
replaced by a S, Se, or Te atom are considered as a kind of
heteroallylic anion system (I-III in Scheme 1). There are 15
possible alkali metal chalcogenocarboxylates for each alkali
metal. It is well documented that the C-O bond lengths of alkali
metal carboxylates are equal or nearly equal1,2 and the negative
charge is delocalized on the carboxylate group.1,2 In contrast,
little is known about the structure of dithiocarboxylic acid alkali
metal salts, which are a very important class of starting
compounds for the synthesis of dithiocarboxylic acid deriva-
tives.3 Houben and Pohl reported in 1907 a valuable method
for construction of the dithiocarboxyl moiety by inserting carbon
disulfide using a Grignard reagent.4 In addition, they noted the
formation of dithioacetic and dithiobenzoic acids by acidolysis
with HCl and of their sodium salts by treatment with aqueous
sodium hydroxide.4 These dithio acids and sodium salts are
obtained as oily substances which contain a small amount of
water and/or solvents which are difficult to remove.5 Such water
and/or solvent contamination has hampered not only their
accurate weighing in stoichiometric reactions but also reactions
which use and/or produce water-sensitive compounds. Previ-
ously, we developed a convenient method for preparing solid
dithiocarboxylic acid alkali metal anhydrous salts by reacting
a dithio acid with alkali metal hydrides such as LiH, NaH, and
KH or with rubidium and cesium acetates in aprotic nonpolar
solvents. However, the use of these metal acetates is somewhat
complicated by the removal of the formed acetic acid.6 Recently,
we have found that O-trimethylsilyl seleno- and tellurocarbox-
ylates react with rubidium and cesium fluorides to give seleno-7
(1) Jeffrey, G, A.; Parry, G. S. J. Am. Chem. Soc. 1954, 76, 5283. Marsh,
R. E. Acta Crystallogr. 1958, 11, 654. Cruickshank, D. W. J.; Jones,
D. W.; Walker, G. J. Chem. Soc. 1964, 1303. Kennard, O.; Walker,
G. J. Chem. Soc. 1963, 5513. Galigne, J. L.; Mouvet, M.; Falgueirettes,
J. Acta Crystallogr. 1970, B26, 368.
(2) Review: Mehrotra, R. C.; Bohra, R. Metal Carboxylates; Academic
Press: 1983, London; pp 157-162.
(3) (a) Couconvanis, D. In Progress in Inorganic Chemistry, Vol. 11;
Lippard, S. J., Ed.; John Wiley & Sons: New York, 1969; pp 234-
356. (b) Kato, S.; Murai, T. In Supplement B: The Chemistry of Acid
DeriVatiVes, Vol. 2, Part 1; Patai, S., Ed.; John Wiley & Sons: New
York, 1992; pp 803-847.
(4) Houben, J.; Pohl, H. Ber. Dtsch. Chem. Ges. 1907, 40, 1303.
(5) Common aromatic dithiocarboxylic acids are oils and cannot be
distilled.
10.1021/ic9808089 CCC: $18.00 © 1999 American Chemical Society
Published on Web 02/08/1999

Heavy Alkali Metal Arenedithiocarboxylates
Inorganic Chemistry, Vol. 38, No. 3, 1999 497
Table 1. Yields of Rubidium Dithiocarboxylates 4 and Cesium
Dithiocarboxylates 5
RCSSM
no.
R
M
method
yielda (%)
4a
CH3
Rb
A
B
A
B
A
B
A
B
B
B
B
B
B
A
B
A
B
A
B
A
B
B
B
B
B
72
68b
61
70
85
77
90
49
58
54
37
38
55
57
75b
54
54
92
77
85
72
58
55
60
72
4b
4c
C2H5
i-C3H7
Rb
Rb
4d
4e
4f
4g
4h
4i
c-C6H11
C6H5
2-CH3C6H4
4-CH3C6H4
4-CH3OC6H4
4-ClC6H4
Rb
Rb
Rb
Rb
Rb
Rb
Rb
Cs
4j
5a
2,4,6-(CH3)3C6H2
CH3
5b
5c
C2H5
Cs
Cs
i-C3H7
5d
5e
5f
5g
5h
5i
c-C6H11
C6H5
4-CH3C6H4
4-CH3OC6H4
4-ClC6H4
Cs
Cs
Cs
Cs
Cs
Cs
Figure 1. ORTEP drawings of potassium (3b), rubidium (4g), and
cesium 4-methylbenzenecarbodithioates (5f). The atoms are drawn with
50% probability thermal ellipsoids. All hydrogen atoms have been
omitted.
2,4,6-(CH3)3C6H2
a Recrystallization from EtOH/ether. b Recrystallization from EtOH/
ether/hexane.
CaF2, SrF2, BaF2) and rubidium and cesium halides (RbX and
CsX, X ) Cl, Br, I) were examined. However, except for the
finding that KF led to a 60% yield of potassium 1-methyleth-
anecarbodithioate (3a), no reaction occurred under various
conditions. The driving force for the formation of 3-5 seems
to arise from the relatively large affinity of the sulfur atom for
K, Rb, and Cs metals compared with other metals and the low
bond energies of KF, RbF, and CsF compared with those of
other metal fluorides. The obtained heavy alkali metal dithio-
carboxylates are yellow to dark red crystals. They are stable
thermally and toward oxygen. Upon exposure to air no ap-
preciable changes were observed for at least 2 weeks both in
the solid state and in solution such as ethanol. They are soluble
in protic and aprotic polar solvents such as methanol and
acetonitrile.
Scheme 2
and tellurocarboxylic acid rubidium and cesium salts.8 This
prompted us to explore the use of the sulfur isologues 5. We
report here a facile synthesis of anhydrous potassium 3, rubidium
4, and cesium dithiocarboxylates 5 and X-ray structural analyses
of sodium (7g), potassium (3b), rubidium (4g), cesium (5f), and
tetramethylammonium 4-methylbenzenecarbodithioates (8e).
Structure. In general, dithiocarboxylic acid alkali metal salts
exist as powders or very thin plates which are unsuitable for
X-ray crystallography. To our knowledge, only Borell and
Lledesert have documented an example in their analysis of
potassium dithioacetate in 1975.9 The exact nature and structures
of alkali metal dithiocarboxylates are still unknown. After
several disappointing attempts to obtain single crystals of
aromatic dithiocarboxylic acid salts (RCSSM, R ) aryl, M )
Na, K, Rb, Cs), single needlelike crystals of sodium (7g),
potassium (3b), rubidium (4g), and cesium 4-methylbenzene-
carbodithioates (5f) were obtained from an ethanol/ether solu-
tion. Their ORTEP drawings are shown in Figure 1. Final atomic
positional parameters are listed in Table 2. Selected bond
distances and angles are shown in Table 3.
Results and Discussion
Synthesis. Initially, the reaction conditions were examined
using trimethylsilyl 1-methylethanecarbodithioate (1c) and ru-
bidium and cesium fluorides. In fact, the reaction proceeded
readily in ether at 20 °C to give the expected rubidium (4c)
and cesium 1-methylethanecarbodithioate (5c) in yields of 50%
and 60%, respectively (method A in Scheme 2). The salts were
synthesized in a straightforward manner using the dithiocar-
boxylic acids themselves (method B in Scheme 1). Table 1
shows the yields of several salts 4 and 5.
To extend this reaction, the reactions of 1c with a variety of
alkali (LiF, NaF, KF) and alkali earth metal fluorides (MgF2,
(6) (a) Kato, S.; Itoh, K.; Hattori, R.; Mizuta, M.; Katada, T. Z.
Naturforsch. 1978, 33b, 976. (b) Yamada, S.; Goto, H.; Terashima,
K.; Mizuta, M.; Katada, T. Z. Naturforsch. 1980, 35b, 458.
(7) Kawahara, Y.; Kato, S.; Kanda, T.; Murai, T.; Ishihara, H. J. Chem.
Soc., Chem. Commun. 1993, 277. Kawahara, Y.; Kato, S.; Kanda, T.;
Murai, T. Bull. Chem. Soc. Jpn. 1994, 67, 1881.
(8) (a) Kawahara, Y.; Kato, S.; Kanda, T.; Murai, T. Chem. Lett. 1995,
87. (b) Kawahara, Y.; Kato, S.; Kanda, T.; Murai, T.; Ebihara, M.
Bull. Chem. Soc. Jpn. 1995, 68, 3507.
These metal salts consist of discrete dimeric units. The two
dithiocarboxylate groups chelate the metal atoms (head to head)
located on the upper and lower sides of the planes which include
the dithiocarboxylate groups. The moieties involving two metals
and four sulfur atoms in the dimer are bipyramidal (Figure 2,
(9) Borel, M. M.; Ledesert, M. Z. Anorg. Allg. Chem. 1975, 415, 285.

498 Inorganic Chemistry, Vol. 38, No. 3, 1999
Kato et al.
Table 2. Crystallographic Data for Potassium (3b), Rubidium (4g), Cesium (5f), and Sodium 4-Methylbenzenecarbodithioates (7g) and
Tetramethylammonium 4-Methylbenzene- (8e) and 2-Methoxybenzenecarbodithioates (8f)
3b
4g
5f
7g
8e
8f
empirical formula
fw
color
C8H7KS2
206.36
red
C8H7RbS2
252.73
red
C8H7CsS2
300.17
red
C8H7Na0.36S2
238.29
red
C12H19NS2
224.23
red
C12H19NOS2
258.58
red
cryst syst
unit-cell dimens
a (Å)
b (Å)
c (Å)
monoclinic
orthorhombic
orthorhombic
orthorhombic
monoclinic
orthorhombic
11.398(1)
6.7021(9)
12.6595(6)
96.022(5)
961.7(1)
P21/c (No. 14)
4
16.768(2)
21.617(2)
10.929(2)
17.346(1)
21.891(2)
10.931(2)
18.727(4)
10.500(2)
4.2192(8)
16.392(2)
9.318(3)
27.493(2)
100.074(9)
4134(1)
P21/c (No. 14)
4
10.481(2)
18.243(2)
7.474(2)
â (deg)
vol of unit cell (Å3)
space group
Z value
3961.3(8)
Fddd (No. 70)
16
4150.7(7)
Fddd (No. 70)
16
829.7(3)
P21212 (No. 18)
4
1429.0(4)
P212121 (No. 19)
4
D
calc (g/cm3)
1.425
1.695
1.921
1.908
1.163
1.196
cryst size (mm)
µ(Mo KR) (cm-1
temp (°C)
0.40 × 0.25 × 0.20 0.25 × 0.20 × 0.20 0.35 × 0.25 × 0.25 0.20 × 0.20 × 0.15 0.43 × 0.40 × 0.20 0.23 × 0.20 × 0.17
)
9.20
53.46
39.09
6.53
3.58
3.54
23.0
23.0
23.0
23.0
23.0
23.0
λ
MoKR (Å)
2θmax (deg)
0.710 69
55.0
total: 2520
2405
0.710 69
55.0
total: 1267
0.710 69
55.0
total: 1338
0.710 69
55.0
total: 3946
1405
0.710 69
55.0
total: 10 018
9861
0.710 69
55.0
total: 1921
1920
no. of measd reflns
no. of unique reflns
no. of observations
(I > 3σ(I))
1607
303
791
513
3324
1035
no. of variables
128
0.030; 0.023
54
54
94
407
0.055; 0.060
1.78
145
0.036; 0.037
1.34
residuals: R,a Rw
0.041; 0.039
1.57
0.028; 0.032
1.46
0.060; 0.066
2.71
b
goodness of fit indicator 1.84
2
a R ) ∑(|Fo| - |Fc|)/∑|Fo|. b Rw ) [∑(|Fo| - |Fc|)2/∑w|Fo| ]1/2, w ) [σ2(Fo) + p2(Fo)2/4]-1
(1.72-1.74 Å) in common dithioesters,10 while the latter is
comparable to that of the common C(sp2)-S single bonds. The
K-S distances of the chelating dithiocarboxyl group are also
different, i.e., 3.2972(9) and 3.354(1) Å.
To our knowledge, such compounds with a CSSM (M )
alkali metal) moiety in which the two C-S and S-M bond
lengths differ (anisobidentate) are rare. In analogous compounds
such as ionic potassium dithioacetate,9 dithiocarbamates3a,b,11
dithioformate, 1,1-dithioxanthates,13,14 and 1,1,2-trithiooxalate15
and dithiocarboxylato transition metal complexes PhCS2Re-
(CO)4,16 (CH3CS2)4Mo,17 (PhCS2)4Mo2(THF)2,18 (PhCS2)2Ni,19
(PhCH2CS2)4Pd2,20 and [4-(i-Pr)C6H4CS2]4Pt2,21 without excep-
tion, the lengths of the two C-S and S-M bonds are equivalent
in the chelated four-membered rings CSSM. This difference
between the C-S bonds seems to indicate a slight localization
of negative charge on the dithiocarboxylate group. The differ-
ence in the K-S bonds explains the apparent difference in C-S
distances involving partial double bonds, and the localization
of an electron on the dithiocarboxylate group. In Figure 3, part
b, the coordination sphere around potassium is shown. It is noted
that the phenyl carbons contact the potassium. The interaction
number of potassium is 8 (six sulfur and two carbon atoms)
(10) (a) Llaguno, E. C.; Mabuni, C. T.; Paul, C. J. Chem. Soc., Perkin
Trans. 2 1976, 239. (b) Adiwidjaja, G.; Voss, J. J. Chem. Res., Synop.
1977, 256; J. Chem. Res, Miniprint 2923. (c) Mikolajczyk, M.;
Kielbasinski, P.; Barlow, J. H.; Russel, D. R. J. Org. Chem. 1977,
42, 23.
(11) Capacci, L.; Vialle, A. C.; Ferrari, M.; Nardelli, M. Ric. Sci. 1967,
37, 993.
(12) Mazzi, F.; Tadini, C. Z. Krystallogr. 1963, 118, 378.
(13) Engler, R.; Kiel, G.; Gattow, G. Z. Anorg. Allg. Chem. 1974, 404, 71.
(14) Mattes, R.; Meschede, W.; Stork, W. Chem. Ber. 1975, 108, 1.
(15) Mattes, R.; Meschede, W.; Stork, W. Chem. Ber. 1976, 109, 2510.
(16) Thiele, G.; Lier, G. Chem. Ber. 1971, 104, 1877.
(17) Dessy, G.; Fares, V.; Scaramamuzza, L. Acta Crystallogr. 1978, B34,
3066.
Figure 2. Top views (a-c) and side views (a′-c′) of the CSSM (M
) K, Rb, Cs) moieties for potassium (3b), rubidium (4g), and cesium
4-methylbenzenecarbodithioates (5f).
part a′: side view). In the case of the potassium salt 3b, a dimer
unit is around an inversion center. The location of the two
potassium metals deviates somewhat from the center of the four
sulfur atoms of the two dithiocarboxylate groups (Figure 2, part
a: top view), and the planes, which include the dithiocarboxylate
group, slip out by ca. 0.14 Å (Figure 2, part a′). The C-S
distances in the dithiocarboxylate group of 3b significantly
differ, 1.670(2) and 1.710(3) Å (Table 3). The former is an
intermediate of the C-S double (1.63-1.64 Å) and single bonds
(18) Cotton, F. A.; Fanwick, P. E.; Niswander, R. H.; Sekutowski, J. C.
Acta Chem. Scand. 1978, A32, 663.
(19) Bonamico, M.; Dessy, G.; Fares, V. J. Chem. Soc. A 1971, 3191.
(20) Bonamico, M.; Dessy, G.; Fares, V. J. Chem. Soc., Dalton Trans.
1977, 2315.
(21) Burk, J. M.; Fackler, J. P. Inorg. Chem. 1972, 11, 3000.

Heavy Alkali Metal Arenedithiocarboxylates
Inorganic Chemistry, Vol. 38, No. 3, 1999 499
Table 3. Selected Bond Lengths (Å), Bond Angles (deg), and Torsion Angles (deg) for Compounds 3b, 4g, 5f, 8e, and 8f
Potassium 4-Methylbenzenecarbodithioate (3b)
Bond Lengths
C1-S1
C1-S2
1.710(3) C3-C4 1.381(4) C6-C7
1.671(2) C4-C5 1.376(4) K1-S1
1.377(4)
3.2972(9) K1-S1#2 3.4486(9) K1-C7#2 3.110(3) K1-C6#2 3.498(3)
3.354(1)
K1-S1#3 3.3448(9) K1-C3#2 3.69 K1-K1#1 3.872(1)
K1-S2#2 5.04 K1-C4#2 4.10
K1-S1#1 3.2555(9) K1-C2#2 3.209(2) K1-C5#2 3.93
C1-C2 1.488(3) C5-C6 1.378(4) K1-S2
C2-C3 1.390(3) C5-C8 1.509(4) K1-S2#1 3.323(1)
Bond Angles
84.84(2) C1-S2-K1
85.92(9) S2-K1-C2#2
S1-C1-S2
123.0(2)
S1-K1-S2#1
95.25(5) K1-C2#2-C7#2 73.3(1)
100.50(5) K1-C7#2-C2#2 81.2(1)
82.47(8) C2#2-K1-C7#2 25.44(6)
S1-K1-S2
S1#1-K1-S2#1
S1-K1-S1#1
53.07(2) S2-C1-C2
53.69(2) C1-S1-K1
107.57(2)
119.3(2)
S1-C1-C2
117.6(2)
S2-K1-C7#2
87.19(8) S2-K1-S1#3 123.48(3) K1-S1#2-C1#2
Torsion Angles
S1-C1-C2-C3
146.9(2)
S2-C1-C2-C3
30.6(3)
K1-S1-C1-C2
148.1(2)
K1-S1-C1-S2
34.4(1)
Rubidium 4-Methylbenzenecarbodithioate (4g)
Bond Lengths
C1-S1 1.682(8) C4-C5
1.37(1)
1.48(2)
Rb1-S1#1
Rb1-S1#3
3.475(4) Rb1#1-S1#1 3.458(4) Rb1-C3#5 3.69(1)
Rb1-Rb1#1 4.376(3)
C1-C2 1.47(2)
C2-C3 1.36(1)
C3-C4 1.38(2)
C5-C6
3.475(4) Rb1#1-S1#3 3.458(4) Rb1-C2#6 3.516(4) Rb1-S1#4
3.94
3.94
Rb1-S1
3.458(4) Rb1#1-S1#2 3.475(4) Rb1-C2#4
3.516(4) Rb1-C3#7 3.69(1)
Rb1-S1#6
Rb1#1-S1 3.475(4) Rb1-S1#2
3.458(4)
Bond Angles
S1-C1-S1#1
S1-Rb1-S1#1
S1-Rb1-S1#2
S1-C1-C2
126(1)
S1#1Rb1-S1#3
S1#1-Rb1-C2#4
S1#2-Rb1-S1#3
101.4(1)
101.4(2)
51.3(1)
Rb1-S1-Rb#1
78.27(8)
84.8(4)
84.3(4)
Rb1-C2#4-C3#5
Rb1-C3#5-C2#4
C2#6-Rb1-C3#7
86.3(6)
80.3(5)
22.5(2)
51.3(1)
102.1(1)
116.9(5)
RbI-S1-C1
Rb1-S1#1-C1
Torsion Angles
S1-C1-C2-C3
S1-C1-C2-C3#1
48.7(6)
131.3(6)
Rb1-S1#2-C1#2-C2#2
Rb1-S1-C1-C2
140.56(6)
140.56(6)
Rb1#1-S1-C1-C2
Rb1-S1-C1-S1#1
140.74(6)
39.44(6)
Cesium 4-Methylbenzenecarbodithioate (5f)
Bond Lengths
C1-S1 1.688(3) C4-C5
C1-C2 1.486(9) C5-C6
C2-C3 1.390(5) Cs1-S1
1.378(6) Cs1-S1#1 3.594(2) Cs1-S1#6 3.964(2) Cs1-C2#4
3.529(2)
3.675(5)
3.561(5)
Cs1-C4#4 3.84
Cs1-C4#5 3.76
Cs1-C5#4 3.91
1.50(1)
Cs1-S1#2 3.581(2) Cs1-C2#6 3.529(2) Cs1-C3#4
3.581(2) Cs1-S1#3 3.594(2) Cs1-C3#6 3.675(2) Cs1-C3#5
C3-C4 1.379(7) Cs1#1-S1 3.594(2) Cs1-S1#4 3.964(2) Cs1-C3#7 3.561(5) Cs1-Cs1#1 4.5932(9)
Bond Angles
S1-C1-S1#1
S1-Cs1-S1#1
S1-Cs1-S1#2
S1-Cs1-S1#3
125.9(4)
49.53(4)
100.63(5)
80.18(4)
S1-Cs1-S1#4
S1-Cs-S1#6
S1-C1-C2
86.889(6)
135.61(1)
117.1(2)
Cs1-S1-C1
85.6(2)
85.2(2)
104.9(1)
84.8(2)
Cs1-Cs#5-C2#4
73.0(2)
22.13(8)
22.61(9)
C1-S1-Cs1#1
Cs1-C2#4-C1#4
Cs1-C2#4-C3#5
C2#4-Cs1-C3#4
C2#4-Cs1-C3#5
Cs1-S1-Cs1#1
79.61(3)
Torsion Angles
S1-C1-C2-C3
S1#1-C1-C2-C3
130.0(3)
50.0(3)
Cs1-S1#2-C1#2-C2#2
Cs1-S1-C1-C2
139.97(2)
139.97(2)
Cs1#1-S1-C1-C2
Cs1-S1-C1-S1#1
140.11(2)
40.03(2)
Tetramethylammonium 4-Methylbenzenecarbodithioate (8e)
Bond Lengths
C1-S1
C1-S2
1.669(6)
1.675(5)
[C1-S
C1-C2
1.675(6)]a
1.485(7)
[C1-C2
C2-C3
1.486(8)]a
1.388(7)
C3-C4
C4-C5
1.391(8)
1.392(8)
C5-C6
C6-C7
1.387(9)
1.377(8)
C2-C7
N-C9
1.402(7)
1.481(6)
Bond Angles
S1-C1-S2
124.8(4)
[S1-C1-S2
125.4(4)]a
S1-C1-C2
117.7(4)
S2-C1-C2
117.5(4)
43.3(7)
[S1-C1-C2
117.8(5)]a
Torsion Angles
S1-C1-C2-C3
Tetramethylammonium 2-Methoxybenzenecarbodithioate (8f)
Bond Lengths
C1-S1
C1-S2
1.675(4)
1.671(4)
C1-C2
C2-C3
1.496(6)
1.394(6)
C3-C4
1.393(7)
1.373(7)
C5-C6
C6-C7
1.358(8)
1.385(7)
C2-C7
N-C9
1.374(6)
1.495(5)
C4-C5
Bond Angles
S1-C1-C2
S1-C1-S2
125.2(3)
116.5(3)
S2-C1-C2
118.1(3)
Torsion Angles
S1-C1-C2-C3
71.6(5)
a The values in square brackets represent the average of the three independent molecules.
(Figure 3, parts a and b). The two carbons are the ipso and
ortho carbons of the phenyl ring of a neighboring molecule (K+-
η2) [K1-C2#2 ) 3.209(2) Å and K1-C7#2 ) 3.110(3) Å,
respectively] (Figure 3, part a; Figure 6, part a).22,23 Such
interaction between an aromatic carbon and alkali metals is the
first example for the compounds having both carboxylate and
chalcogenocarboxylate groups, although the following have been
reported: η2 and η3 interactions between Ph2P(PhCH)K (K-

500 Inorganic Chemistry, Vol. 38, No. 3, 1999
Kato et al.
Figure 3. Packing (a) of potassium 4-methylbenzenecarbodithioate
(3b) and coordination sphere (b) around the potassium. The atoms are
drawn with 50% probability thermal ellipsoids. All hydrogen atoms
have been omitted.
Figure 5. Packing (a) of cesium 4-methylbenzenecarbodithioate (5f)
and coordination sphere (b) around the cesium. The atoms are drawn
with 50% probability thermal ellipsoids. All hydrogen atoms have been
omitted.
Figure 4. Packing (a) of rubidium 4-methylbenzenecarbodithioate (4g)
and coordination sphere (b) around the rubidium. The atoms are drawn
with 50% probability thermal ellipsoids. All hydrogen atoms have been
omitted.
Figure 6. Front views (a, b, c) of the coordination of the ipso and
ortho carbons to the potassium, rubidium, and cesium in the salts 3b,
4g, and 5f, respectively. The phenyl rings which are bonded to the
central dithiocarboxylate carbons (C1 and C1#1 or C1#2) are omitted.
C, 3.01∼3.25 Å);24 (2-C5H4N)(Ph2CHPh2CHK‚2THF);25 Ph2-
(2-C5H4N)CK‚PMDTA‚THF (K-C, 3.14-3.46 Å);26 η5
)
dianion triple salt where K+ interacts η5 to the ring (K-C, 3.02-
3.12 Å) which was obtained by reduction of tetraphenylbuta-
diene with potassium; η6 ) Ph3CK‚THF‚PMDTA (K-C, 3.14-
3.25 Å);27 [(Ph3P)2(Ph2PC6H4)RuH2]2C10H8‚Et2O (K-C, 2.61-
2.97 Å),28 (PhMe2P)OsH3K (K-C, 3.12-3.60 Å),29 [(2,6-i-
Pr2C6H3O)4Nd]K (K-C, 3.12-3.47 Å),30 η6-benzene contacts,31
(22) (a) Schade, C.; Schleyer, P. v. R. AdV. Organomet. Chem. 1987, 27,
169. (b) Jutzi, P. AdV. Organomet. Chem. 1986, 26, 217. (c) Wakefield,
B. J. In ComprehensiVe Organic Synthesis; Trost, B. M., Fleming, I.,
Eds.; Pergamon Press: Oxford, 1991; Vol. 1, p 1.
(23) Hoffmann, D. N.; Bauer, W.; Hampel, F.; van Eikema Hommes, N.
J. R.; Schleyer, P. v. R.; Otto, P.; Pieper, U.; Stalke, D.; Wright, D.
S.; Snaith, R. J. Am. Chem. Soc. 1994, 116, 528.
(24) Schmidbaur, H.; Deschler, U.; Milewski-Mahrla, B.; Zimmer-Gasser,
B. Chem. Ber. 1981, 114, 608.
(25) Schmidbaur, H.; Deschler, U.; Milewski-Mahrla, B. Chem. Ber. 1982,
115, 3290.
(27) Hoffmann, D.; Bauer, W.; Schleyer, P. v. R.; Pieper, U.; Stalke, D.
Organometallics 1993, 12, 1193.
(28) Pez, G. P.; Grey, R. A.; Corsi, J. J. Am. Chem. Soc. 1981, 103, 7528.
(29) Huffman, J. C.; Green, M. A.; Kaiser, S. L.; Caulton, K. G. J. Am.
Chem. Soc. 1985, 107, 5111.
(26) Pieper, U.; Stalke, D. Organometallics 1993, 12, 1201.

Heavy Alkali Metal Arenedithiocarboxylates
Inorganic Chemistry, Vol. 38, No. 3, 1999 501
alkali metal graphite intercalates (K-C, 3.05 Å),32 [(PMDTA)-
PhCH2M] [M ) K (M-C, 3.15-3.29 Å), M ) Rb (Rb-C,
3.35-3.64 Å)],33 N-rubidiocarbazole‚PMDTA (Rb-C, 3.42-
3.68 Å),33 and Ph3CRb‚M(PMDTA)n (Rb-C, 3.35-3.64 Å).26
In the rubidium salt 4g a dimer unit is around the 222 site. A
2-fold axis is through the rubidium atoms, and another is through
the dithiocarboxylate groups of which C1, C2, C5, and C6 are
on the axis. In contrast to the potassium salt 3b, the two
dithiocarboxylates groups of the rubidium salt 4g are in the same
plane and the two metals on the upper and lower sides are
located almost in the center of the four sulfur atoms of the
opposing dithiocarboxylate groups (Figure 2, parts b and b′).
The C-S bond distances [1.682(8) and 1.682(8) Å] of the
dithiocarboxyl group are equal, indicating electronic delocal-
ization overall for the CSS group. The eight Rb-S distances
[3.458(4) Å for Rb1-S1, Rb1-S1#2, Rb1#1-S1#1, and Rb1#1-
S1#3; 3.475(4) Å for Rb1-S1#1, Rb1-S1#3, Rb1#1-S1, and
Rb1#1-S1#2] of 4g are very similar and do not differ from
accepted values 3.442-3.494 Å which were found for rubidium
thioacetate.34 The interaction number of Rb with surrounding
atoms is 8 (Figure 4, part b), Rb being surrounded by four sulfur
and four carbon atoms which are ipso and ortho carbon atoms
of the neighboring two phenyl rings which are close to the metal
[Rb1-C2#4 ) 3.516(4) Å, Rb1-C3#5 ) 3.69(1) Å, Rb1-C2#6
) 3.516(4) Å, Rb1-C3#7 ) 3.69(1) Å, respectively (Rb+-η2)]
(Figures 4, and 6, part b). The cesium salt 5f is isostructural
with 4g, and the geometries of both salts are very similar (Figure
2, parts c and c′). The interaction number of the cesium is 12
(Figure 5, parts a and b), Cs being surrounded by six sulfur
atoms, four of which are those in the same plane involving two-
faced dithiocarboxyl groups, and by six carbon atoms of two
tolyl groups of the neighboring molecules, in which one ipso
and two ortho carbon atoms are close to the metal [Cs1-C2#4
) 3.529(2) Å, Cs1-C3#4 ) 3.675(5) Å, and Cs1-C3#5 ) 3.561-
(5) Å, and Cs1-C2#6 ) 3.529(2) Å, Cs1-C3#6 ) 3.675(5) Å,
and Cs1-C3#7 ) 3.561(5) Å, respectively (Cs+-η3)] (Figures
5 and 6, part c). The distances of Cs-Cipso are shorter than
those of Cs-Cortho. It is noted that the distances between meta
or para carbons and cesium (Cs1-C4#4, Cs1-C4#5, Cs1-C5#4,
Cs1-C4#6, Cs1-C4#7, Cs1-C5#6) are 3.76-3.91 Å, suggesting
a weak interaction.31d,f The four Cs-S distances (Cs1-S1, Cs1-
S1#1, Cs1-S1#2, Cs1-S1#3) are equivalent [3.581(2)-3.594-
(2) Å], which agrees with the values for cesium 1,1-
dithiooxalate,35 and are shorter than the values calculated from
the sum of the ionic radii of sulfur36 and cesium atoms,37
respectively. In contrast, the distances of Cs1-S1#4 [3.964(2)
Å] and Cs1-S1#6 [3.964(2) Å] are much longer. The interaction
(coordination?) number of these ipso and ortho carbons with
hydrogen, carbons, and metals is 4. The coordination number
Table 4. Deviation of the Metal Cations from the CSS Plane in
Alkali Metal Dithiocarboxylates
Table 5. Dihedral Angles between the Phenyl Ring and the CSS
Plane in Alkali Metal 4-Methylbenzenecarbodithioates
of the sulfur atom is 3 (two potassiums and one carbon) and 5
(four potassiums and one carbon) for 3b, 3 (two rubidiums and
one carbon) for 4g, and 4 (three cesiums and one carbon) for
5f, respectively.
The angles (θ) between the dithiocarboxylate plane [CSS]
and the plane [SSM] and the distances (d) between the [CSS]
plane and the alkali metal (M) of the salts 7g, 3b, 4g, and 5f
are listed in Table 4. The angle of the potassium is small
compared with those of the rubidium 4g and cesium 5f. The
significantly longer K-K [3.872(1) Å], Rb-Rb [4.376(4) Å],
and Cs-Cs distances [4.593(1) Å] in the dimeric units of 3b,
4g, and 5f related to the values (3.04 Å for K, 3.32 Å for Rb,
and 3.62 Å for Cs)37 calculated from the sum of the ionic radii
of these metals clearly indicate the absence of bonding between
the two metals. Table 5 shows the dihedral angles (τ) of the
dithiocarboxyl and the aromatic ring planes. The angles increase
in the order K, Rb, and Cs. The magnitude of these angles might
be influenced by coordination of the aromatic ring to the metals.
The successful single crystallization of potassium, rubidium,
and cesium salts prompted us to prepare the single crystals of
the corresponding lithium salt 6b and sodium salt 7g. Despite
extensive attempts to crystallize a variety of lithium dithiocar-
boxylates 6 and sodium dithiocarboxylates 7, it was difficult to
obtain single crystals suitable for X-ray crystallography. Due
to the poor crystal quality, the X-ray structure analysis of sodium
4-methylbenzenecarbodithioate (7g) revealed the presence of
CH3C6H4CS2Na0.36 at the level of R/Rw ) 0.060/0.066. There-
fore, we could not discuss the geometry in detail, although 7g
appeared to be a monomer and there appeared the possibility
of some localization of the negative charge on the dithiocarboxyl
group, which was also suggested from the structure of 3b.
To our knowledge, no crystal analysis of ammonium dithio-
carboxylates has been reported. Since the first isolation of
crystalline ammonium dithiocarboxylates in 1972,38 a variety
of ammonium dithiocarboxylates have been prepared.39-41
However, quaternary ammonium dithiocarboxylate has been
limited to only tetramethylammonium 2-methylpropanecar-
bodithioate and benzenecarbodithioate42 and tetraethylammo-
nium 2-hydroxybenzenecarbodithioate43 and tetrathiooxalates,44
(30) Clark, D. C.; Watkin, J. G.; Huffman, J. C. Inorg. Chem. 1992, 31,
1556.
(31) (a) Atwood, J. L.; Hrncir, D. C.; Priester, R. D.; Rogers, R. D.
Organometallics 1983, 2, 985. (b) Atwood, J. L.; Hrncir, D. C.; Rogers,
R. D. J. Inclusion Phenom. 1983, 1, 199. (c) Atwood, J. L.; Crissinger,
K. D.; Priester, R. D.; Rogers, R. D. J. Organomet. Chem. 1978, 155,
1. (d) Atwood, J. L. J. Inclusion Phenom. 1985, 3, 13. (e) Atwood, J.
L. Recent DeV. Sep. Sci. 1977, 3, 195. (f) Marsh, R. J. Cryst. Mol.
Struct. 1977, 10, 163.
(32) (a) Ru¨dorff, W. AdV. Inorg. Chem. Radiochem. 1959, 1, 223. (b) Solin,
S. A. AdV. Chem. Phys. 1982, 49, 455. (c) Levy, F. Intercalated
Layered Materials; Reidel: Dordrecht, 1979.
(33) Gregory, K. Ph.D. Thesis, Universita¨t Erlangen-Nu¨rnberg, 1991.
(34) Borel, M. M.; Dupriez, G.; Lledesert, M. J. Inorg. Nucl. Chem. 1975,
37, 1533.
(35) Mattes, R.; Meschede, W. Chem. Ber. 1976, 109, 1832.
(36) Pauling, L. The Nature of the Chemical Bond; Cornell University
Press: Ithaca, NY, 1948; 195.
(38) Kato, S.; Mizuta, M. Bull. Chem. Soc. Jpn. 1972, 45, 3492.
(39) Kato, S.; Mitani, T.; Mizuta, M. Int. J. Sulfur Chem. 1973, 8, 359.
(40) Kato, S.; Mizuta, M. Int. J. Sulfur Chem. A 1972, 2, 275.
(41) Kato, S.; Chiba, S.; Mizuta, M.; Ishida, M. Z. Naturforsch. 1982, 37b,
736.
(42) Bonnans-Plaisance, C.; Gressier, J. C.; Levesque, G.; Mahjoub, A.
Bull. Soc. Chim. Fr. 1985, 981.
(37) Slater, J. C. J. Chem. Phys. 1964, 10, 3199.

502 Inorganic Chemistry, Vol. 38, No. 3, 1999
Kato et al.
Table 6. IR and 13C NMR Spectra of Alkali Metal
Dithiocarboxylates
RCSSM
R
M
ν
asymCS2a (cm-1
)
13CdSb (δ)
i-C3H7
Li (6a)
Na (7a)
K (3a)
Rb (4b)
Cs (5c)
Li (6b)
Na (7g)
K (3b)
Rb (4g)
Cs (5f)
952
956
949
949
953
1028
1015
1015
1008
1025
275.8
275.6
277.2
277.0
276.7
256.0
256.0
256.1
256.1c
249.9c
4-CH3C6H4
a KBr. b CD3OD. c DMSO-d6.
Table 7. Reactiona of Alkali Metal Dithiocarboxylates
4-CH3C6H4CSSM, 3-7, with Methyl Iodide
run
M
temp (°C)
yield of 9 (%)
Figure 7. ORTEP drawings of tetramethylammonium 4-methyl- (8e)
(a) and 2-methoxybenzenecarbodithioates (8f) (b). The atoms are drawn
with 50% probability thermal ellipsoids.
1
2
3
4
5
6
7
8
9
Li (6b)
Na (7g)
K (3b)
Rb (4g)
Cs (5f)
Li (6b)
Na (7g)
K (3b)
Rb (4g)
Cs (5f)
0
0
0
0
0
20
20
20
20
20
59
86
92
29
22
91
97
94
35
22
Scheme 3
10
a For 30 min.
Spectra. The 13C NMR spectra of alkali metal dithiocar-
boxylates have not yet been described in the literature, although
1
IR, electron, and H NMR spectra have been reported.6 The
stretching frequencies and the carbon-13 chemical shifts of the
dithiocarboxyl group of alkali metal 1-methylethane- and
4-methylbenzenecarbodithioates (3-7) are shown in Table 6.
The dithiocarboxyl carbon signals are observed in the range δ
250-277. The alkali metal cations appeared to have very little
influence on these signals.
Reaction. To our knowledge, there has been no systematic
investigation concerning the reactivity of alkali metal dithio-
carboxylates.45 To compare the reactivities, the reactions of
alkali metal 4-methylbenzenecarbodithioates with alkyl and
organotin halides were carried out. The lithium 6, sodium 7,
and potassium salts 3 readily reacted with methyl iodide at room
temperature to give the corresponding methyl ester 9 in
quantitative yields, while the reaction with rubidium 4 and
cesium salts 5 resulted in low yields. At 0 °C, however, the
reactivity of 6 to methyl iodide substantially decreased compared
with those of the corresponding sodium 7 and potassium salts
3 (Table 7). The reaction with triorganotin chlorides at 20 °C
led to high yields of the corresponding triorganotin dithioesters
10 (Scheme 4).
Summary. We have developed an alternative method for
preparing heavier alkali metal dithiocarboxylates by reaction
of dithiocarboxylic acid or its trimethylsilyl ester with the
corresponding alkali metal fluorides. In the solid state, potas-
sium, rubidium, and cesium 4-methylbenzenecarbodithioates
have a dimeric structure in which the alkali metal cations are
located on the upper and lower sides of the plane involving the
two opposing dithiocarboxylate groups. Each of the rubidium
and cesium cations is located in the center of the four sulfur
most likely due to the difficulty of preparation and purification.
Their X-ray structural analyses have not been described.
Recently, we have found that alkali metal tellurocarboxylates
readily react with tetramethylammonium chloride to give the
corresponding ammonium arenecarbotelluroates.8b This prompted
us to prepare tetramethylammonium dithiocarboxylates. After
several attempts, we succeeded in preparing a series of tetra-
methylammonium dithiocarboxylates 8 in 40-90% yields
(Scheme 3). The obtained tetramethylammonium salts 8 are
stable thermally and toward oxygen. Upon exposure to air, no
appreciable changes were observed for at least 1 week, and they
can be stored at 0 °C under nitrogen for over 6 months. The
ORTEP drawings of tetramethylammonium 4-methyl- (8e) and
2-methoxybenzenecarbodithioate (8f) are shown in Figure 7.
Final atomic positional parameters are listed in Table 2. Selected
bond distances and angles are shown in Table 3. For 8e, three
independent molecules were present in one asymmetric unit.
As opposed to the above-mentioned heavy alkali metal salts,
8e and 8f exist as monomers, in which the tetramethylammo-
nium cation is located outside the plane of the dithiocarboxyl
group (Figure 7). The C-S bond lengths of the dithiocarboxylate
groups of both salts are almost equal, 1.672(4)-1.678(5) Å,
indicating the localization of negative charge on the dithiocar-
boxyl group. The dihedral angles of the dithiocarboxyl plane
and the aromatic ring in 8e and 8f are 49.3° and 70.9°,
respectively, larger than those of the corresponding alkali metal
salts.
(43) Mereiter, K.; Mikenda, W.; Steinwender, E. J. Crystallogr. Spectrosc.
Res. 1993, 23, 397.
(44) Bacher, A. D.; Iran Sens; Mu¨ller, U. Z. Naturforsch. 1992, 47b, 702.
(45) Murai, T.; Kato, S. In ComprehensiVe Organic Functional Group
Transformations, Vol. 5; Moody, C. J., Ed.; Pergamon Press: New
York, 1995; pp 545-563.

Heavy Alkali Metal Arenedithiocarboxylates
Inorganic Chemistry, Vol. 38, No. 3, 1999 503
Table 8. 13C NMR Spectral Data for Trimethylsilyl Dithiocarboxylates 1, Dithiocarboxylic Acids 2, Lithium Dithiocarboxylate 6b, and Sodium
Dithiocarboxylate 7g
no.
compd
13C NMRa (δ)
1a
1b
1c
1d
2a
2b
2c
2d
2e
2f
2g
2h
2i
2j
6b
7g
CH3CSSSiMe3
C2H5CSSSiMe3
i-C3H7CSSSiMe3
c-C6H11CSSSiMe3
CH3CSSH
C2H5CSSH
i-C3H7CSSH
4.5 (CH3Si), 44.3 (CH3), 238.3 (CdS)
4.1 (CH3Si), 20.8 (CH3), 49.3 (CH2), 245.3 (CdS)
4.2 (CH3Si), 24.0 (CH3), 53.6 (CH), 252.0 (CdS)
4.3 (CH3), 25.6 (CH2), 26.0 (CH2), 34.5 (CH2), 64.1 (CH), 250.7 (CdS)
40.1 (CH3), 230.6 (CdS)
14.6 (CH3), 46.6 (CH2), 239.7 (CdS)
23.9 (CH3), 50.8 (CH), 246.1 (CdS)
c-C6H11CSSH
C6H5CSSH
26.8, 27.2, 36.1, 68.9 (CH, CH2), 274.0 (CdS)
126.8, 128.6, 133.2 (Ar), 225.4 (CdS)
2-CH3C6H4CSSH
4-CH3C6H4CSSH
4-CH3OC6H4CSSH
4-ClC6H4CSSH
2,4,6-(CH3)3C6H2CSSH
4-CH3C6H4CSSLib
4-CH3C6H4CSSNab
21.5 (CH3), 113.4, 113.7, 127.9, 128.5, 129.4, 136.7 (Ar), 221.9 (CdS)
20.7 (CH3), 126.8, 127.0, 129.1, 140.0, 144.7 (Ar), 224.6 (CdS)
55.7 (CH3O), 113.5, 129.4, 136.6, 164.4 (Ar), 222.3 (CdS)
128.1, 128.6, 140.0, 141.4 (Ar), 223.1 (CdS)
19.1 (CH3), 21.0 (o-CH3), 128.6, 131.2, 138.1, 146.2 (Ar), 246.0 (CdS)
21.3 (CH3), 127.8, 128.2, 140.5, 151.9 (Ar), 256.0 (CdS)
21.2 (CH3), 127.9, 128.2, 140.7, 151.8 (Ar), 256.0 (CdS)
a CDCl3. b CD3OD.
Mo KR radiation (λ ) 0.710 69 Å). A Rigaku XR-TCS-2-050
temperature controller was used for low-temperature measurement. All
of the structures were solved and refined using the teXsan crystal-
lographic software package on an IRIS Indigo computer. The crystals
of 3b, 4g, 5f, 7g, 8e, and 8f were cut from the grown needles. The
crystals were mounted on a glass fiber. The cell dimensions were
determined from a least-squares refinement of the setting diffractometer
angles for 25 automatically centered reflections. Three standard
reflections were measured every 150 reflections, and no decay was
detected. Lorentz and polarization corrections were applied to the data,
and empirical absorption corrections (DIFABS47) were also applied.
The structures was solved by direct methods using SHELXS8648 for
3b, 4g, 5f, 8e, and 8f and SAPI 9149 for the Na salt 7g and expanded
using DIRDIF92.50 Scattering factors for neutral atoms were from
Cromer and Waber,51 and anomalous dispersion52 was used. The
function minimized was ∑w(|Fo| - |Fc|)2, and the weighting scheme
employed was w ) [σ2(Fo) + p2(Fo)2/4]-1. A full-matrix least-squares
refinement was executed with non-hydrogen atoms being anisotropic
for 3b, 4g, 5f, 8e, and 8f. For 7g, non-hydrogen atoms except for the
sodium atom were refined anisotropically. The final least-squares cycle
included fixed hydrogen atoms at calculated positions of which each
isotropic thermal parameter was set to 1.2 times of that of the connecting
atom.
Scheme 4
atoms of the two dithiocarboxylate groups. In contrast to these
heavier alkali metal salts, the geometry of the corresponding
aromatic sodium dithiocarboxylate is significantly different,
fundamentally a monomer. The coordination sphere of the
cations of the K, Rb, and Cs salts is completed by two chelating
dithiocarboxylate ligands and by one or two aromatic rings in
which the ipso and ortho carbons are close to the cation,
indicating the presence of nonbonding interaction. The C-S
distances of the dithiocarboxylate group in the sodium and
potassium salts are different, which seems to indicate some
electronic localization on the dithiocarboxyl group. On the other
hand, the C-S distances of the rubidium and cesium salts are
equal, indicating a high degree of electronic delocalization on
the dithiocarboxylate group.
Crystal Growth for X-ray Diffraction. Solvents: EtOH/Et2O )
0.3 mL/1.5 mL for 3b and 4g, EtOH/Et2O ) 0.3 mL/1.0 mL for 5f,
MeOH/Et2O ) 0.3 mL/1.0 mL for 7g, EtOH/Et2O ) 0.2 mL/1.0 mL
for 8e and CH3CN/hexane/ether ) 0.3 mL/0.8 mL/0.1 mL for 8f. The
diethyl ether (1-2 mL) was layered on the top of the alcohols or
acetonitrile solution containing the salts. The single crystals of these
salts were grown for 0.5-2 days at -20 °C.
Experimental Section
The details regarding the generic instruments given in ref 8b apply
as well to this study.
Synthesis of Potassium 3, Rubidium 4, and Cesium Dithiocar-
boxylates 5. The preparations of rubidium 1-methylethanecarbodithioate
(4c) (method A), rubidium benzenecarbodithioate (4e) (method B),
cesium 1-methylethanecarbodithioate (5c) (method A), and cesium
benzenecarbodithioate (5e) (method B) are described in detail as typical
Materials. Dithiocarboxylic acids 2 were prepared by acidolysis of
the corresponding piperidinium dithiocarboxylates38,39 with concentrated
hydrogen chloride. Trimethylsilyl dithiocarboxylates 146 and lithium
66b and sodium dithiocarboxylates 76a were prepared by the method
described in the literature. Additional spectral data of 1, 2, and the
lithium 6b and sodium dithioates 7g are shown in Table 8. Rubidium
fluorides (Aldrich) and other alkali and alkali earth metal fluorides
(Nacalai Tesque Co., Kyoto, Japan) were purchased. They were dried
under reduced pressure at >120 °C before use. The following solvents
were purified under argon and dried as indicated: diethyl ether and
hexane, refluxed with sodium metal using benzophenone as indicator
and distilled before use; acetonitrile, distilled over phosphorus pen-
toxide, after refluxing for 5 h. Ethanol was refluxed and distilled on
magnesium flakes. All manipulations were carried out under argon.
X-ray Measurements. The measurement was carried out on a
Rigaku AFC7R four-circle diffractometer with graphite-monochromated
(47) Walker, N.; Stuart, W. Acta Crystallogr. 1983, A39, 158.
(48) Sheldrick, G. M. In Crystallographic Computing 3; Sheldrick, G. M.,
Kruger, C., Goddard, R., Eds.; Oxford University Press: Oxford, U.K.,
1985; pp 175-189.
(49) Fan Hai-Fu, Structure Analysis Programs with Intelligent Control,
Rigaku Corporation, Tokyo, Japan, 1991.
(50) Beurskens, P. T.; Admiraal, G.; Beurskiens, G.; Bosman, W. P.; Garcia-
Granda, S.; Gould, R. O.; Smits, J. M. M.; Smykalla, C. The DIRDIF
program system. Technical Report of the Crystallography Laboratory;
University of Nijmegen: The Netherlands, 1992.
(51) Cromer, D. T.; Waber, J. T. International Tables for X-ray Crystal-
lography; The Kynoch Press: Birmingham, U.K., 1974; Vol. IV, Table
2.2A.
(52) Creagh, D. C.; McAuley, W. J. In International Tables for X-ray
Crystallography; Wilson, A. J. C., Ed.; Kluwer Academic Publish-
ers: Boston, 1992; Vol. C, Table 4.2.6.8, pp 219-222.
(46) Kato, S.; Mizuta, M.; Ishii, Y. J. Organomet. Chem. 1973, 55, 121.

504 Inorganic Chemistry, Vol. 38, No. 3, 1999
Kato et al.
procedures. Their yields are shown in Table 1. The structures of 3-5
were confirmed by comparison of spectral data with those of authentic
samples. The IR spectra were exactly consistent with those of authentic
samples prepared by the reactions of the dithiocarboxylic acids with
the corresponding metal hydrides or acetates.4
Potassium 1-Methylethanecarbodithioate (3a). Method A: yellow
plates. Mp: 178-180 °C dec. IR (KBr): 949 (νCSS) cm-1. 1H NMR
(CD3OD): δ 1.24 (d, 6H, CH3), 3.59 (sept, 1H, CH). 13C NMR (CD3-
OD): δ 21.3 (CH3), 58.0 (CH2), 277.2 (CdS).
(ipso-C), 256.1 (CdS). Anal. Calcd for C8H7S2Rb (252.72): C, 38.02;
H, 2.79. Found: C, 37.73; H, 3.04.
Rubidium 4-Methoxybenzenecarbodithioate (4h). Method B: red
crystals [recrystallization from ethanol/ether (1:2) at -20 °C]. Mp:
1
193-194 °C dec. IR (KBr): 1018 (νCSS) cm-1. H NMR (CD3OD):
δ 3.30 (s, 3H, CH3), 6.76 (d, 2H, Ar), 8.35 (d, 2H, Ar). 13C NMR
(CD3OD): δ 55.8 (CH3O), 112.6 (p-C), 129.9 (m-C), 146.5 (o-C), 163.0
(ipso-C), 254.0 (CdS). Anal. Calcd for C8H7OS2Rb (268.73): C, 37.76;
H, 2.63. Found: C, 37.77; H, 2.81.
Potassium 4-Methylbenzenecarbodithioate (3b). Method B: dark
Rubidium 4-Chlorobenzenecarbodithioate (4i). Method B: red
brown crystals [recrystallization from ethanol/ether (1:2) at -20 °C].
Mp: 225-226 °C dec. IR (KBr): 1008 (νCSS) cm-1. 1H NMR (CD3-
OD): δ 7.19 (d, 2H, Ar), 8.18 (d, 2H, Ar). 13C NMR (CD3OD): δ
127.6 (p-C), 129.1 (m-C), 136.3 (o-C), 152.7 (ipso-C), 254.2 (CdS).
Anal. Calcd for C7H4S2ClRb (273.14): C, 30.44; H, 1.48. Found: C,
30.43; H, 1.47.
red crystals, 0.298 g (44%). Mp: 210-211 °C dec. IR (KBr): 1015
1
(νCSS) cm-1. H NMR (CD3OD): δ 2.31 (s, 3H, CH3), 7.02-8.11
(m, 4H, Ar). 13C NMR (CD3OD): δ 21.3, 127.2, 128.2, 140.6, 151.7
(Ar), 256.1 (CdS).
Rubidium Dithioacetate (4a). Method A: yellow plates, 0.304 g
1
(72%). Mp 201-203 °C dec. IR (KBr): 873 (νCSS) cm-1. H NMR
(CD3OD): δ 3.04 (s, 3H, CH3). 13C NMR (CD3OD): δ 50.1 (CH3),
264.0 (CdS).
Rubidium 2,4,6-Trimethylbenzenecarbodithioate (4j). Method B:
reddish orange crystals [recrystallization from ethanol/ether (1:2) at
Rubidium Dithiopropanoate (4b). Method A: yellow plates
[recrystallization from ethanol/ether (1:3)]. Mp 186-188 °C dec. IR
1
-20 °C]. Mp: 200-202 °C dec. IR (KBr): 1013 (νCSS) cm-1. H
NMR (CD3OD): δ 2.20 (s, 6H, 2,6-CH3), 2.35 (s, 3H, 4-CH3), 6.73
(s, 2H, Ar). 13C NMR (CD3OD): δ 18.4 (2,6-CH3), 19.4 (4-CH3), 128.8
(p-C), 130.2 (m-C), 134.8 (o-C), 156.8 (ipso-C), 263.8 (CdS).
Cesium Dithioacetate (5a). Method B: orange plates [recrystalli-
zation from ethanol/ether (1:2) at -20 °C]. Mp: 201-203 °C dec. IR
1
(KBr): 934 (νCSS) cm-1. H NMR (CD3OD): δ 1.35 (t, 3H, CH3),
3.14 (q, 2H, CH2). 13C NMR (CD3OD): δ 17.3 (CH3), 55.7 (CH2),
274.0 (CdS).
Rubidium 1-Methylethanecarbodithioate (4c). Method A. A
solution of trimethylsilyl 1-methylethanecarbodithioate (2.00 g, 10.4
mmol) in ether (5 mL) was added to rubidium fluoride (0.728 g, 6.97
mmol), and the mixture was stirred for 2 h at 20 °C. The resulting
precipitates were filtered out and washed with ether (3 × 3 mL). The
precipitates were dissolved in acetonitrile (5 mL), and the insoluble
part was filtered out. Evaporation of the acetonitrile under reduced
pressure and recrystallization from a mixed solvent (8 mL) of ethanol
and ether (1:3) at -20 °C for 17 h gave rubidium 1-methylethanecar-
bodithioate (4c) as yellow plates: 1.22 g (85%). Mp 189-191 °C dec.
IR (KBr): 949 (νCSS) cm-1. 1H NMR (CD3OD): δ 1.24 (d, 6H, CH3),
3.59 (sept, 1H, CH). 13C NMR (CD3OD): δ 25.3 (CH3), 58.1 (CH2),
270.0 (CdS). UV/vis (EtOH): 340, 459 nm. Anal. Calcd for C4H7S2-
Rb (204.69): C, 23.47; H, 3.45. Found: C, 23.47; H, 3.56.
Method B: yellow plates [recrystallization from ethanol/ether (1:3)
at -20 °C, for 18 h]; 77%.
1
(KBr): 875 (νCSS) cm-1. H NMR (CD3OD): δ 3.03 (s, 3H, CH3).
13C NMR (CD3OD): δ 50.3 (CH3), 263.9 (CdS).
Cesium Dithiopropanoate (5b). Method A: orange plates [recrys-
tallization from ethanol/ether (1:2) at -20 °C]. Mp: 169-171 °C dec.
IR (KBr): 934 (νCSS) cm-1. 1H NMR (CD3OD): δ 1.13 (t, 3H, CH3),
3.13 (q, 2H, CH2). 13C NMR (CD3OD): δ 17.3 (CH3), 55.7 (CH2),
274.0 (CdS).
Cesium 1-Methylethanecarbodithioate (5c). Method A. A solution
of trimethylsilyl 1-methylethanecarbodithioate (2.28 g, 11.8 mmol) in
ether (5 mL) was added to cesium fluoride (1.020 g, 6.70 mmol), and
the mixture was stirred for 2 h at 20 °C. The resulting precipitates
were filtered out and washed with ether (3 × 3 mL). The precipitates
were dissolved in acetone (5 mL), and the insoluble part was filtered
out. Evaporation of the acetonitrile under reduced pressure and
recrystallization from a mixed solvent (4.5 mL) of ethanol and ether
(1:2) at -20 °C for 15 h gave cesium 1-methylethanecarbodithioate
(5c) as yellow plates: 1.55 g (92%). Mp: 155-159 °C dec. IR (KBr):
953 (νCSS) cm-1. 1H NMR (CD3OD): δ 1.24 (d, 6H, CH3), 3.58 (sept,
1H, CH). 13C NMR (CD3OD): δ 25.3 (CH3), 58.1 (CH), 276.6 (Cd
S).
Method B: yellow plates [recrystallization from ethanol/ether (1:
2) at -20 °C, for 20 h]; 77%.
Cesium Cyclohexanecarbodithioate (5d). Method A: yellow plates
[recrystallization from ethanol/ether (1:3)]. Mp: 195-196 °C dec. IR
(KBr): 986 (νCSS) cm-1. 1H NMR (CD3OD): δ 1.27-1.91 (m, 10H,
CH2), 3.23 (m, 1H, CH). 13C NMR (CD3OD) δ 27.1, 27.5, 36. 3 (CH2),
69.4 (CH), 275.0 (CdS).
Rubidium Cyclohexanecarbodithioate (4d). Method A: yellow
plates [recrystallization from ethanol/ether (1:3)], 1.09 g (90%). Mp
195-196 °C dec. IR (KBr): 967 (νCSS) cm-1. 1H NMR (CD3OD): δ
1.18-1.19 (m, 10H, CH2), 3.24 (m, 1H, CH). 13C NMR (CD3OD): δ
26.8, 27.2, 36.1, 68.9 (CH, CH2), 274.0 (CdS).
Rubidium Benzenecarbodithioate (4e). Method B: A solution of
benzenecarbodithioic acid (0.99 g, 4.14 mmol) in ether (5 mL) was
added to rubidium fluoride (0.207 g, 1.98 mmol), and the mixture was
stirred for 2 h at 20 °C. The resulting precipitates were filtered out and
washed with ether (3 × 3 mL). The precipitates were dissolved in
ethanol (8 mL), and the insoluble part was filtered out. The ethanol
was evaporated under reduced pressure. The residue was dissolved in
ethanol (3 mL), ether (6 mL) was slowly added, and the mixture was
allowed to stand at -20 °C for 17 h. Filtration of the resulting crystals
gave 0.231 g (49%) of rubidium benzenecarbodithioate (4e) as dark
Cesium Benzenecarbodithioate (5e). Method B. A solution of
benzenecarbodithioic acid (0.87 g, 4.18 mmol) in ether (5 mL) was
added to cesium fluoride (0.292 g, 1.92 mmol), and the mixture was
stirred for 3 h at 20 °C. The resulting precipitates were filtered out and
washed with ether (3 × 3 mL). The precipitates were dissolved in
ethanol (15 mL), and the insoluble part was filtered out. The ethanol
was removed under reduced pressure. The residue was dissolved in
ethanol (20 mL), then ether (20 mL) was added, and the mixture was
allowed to stand at -20 °C for 15 h. Filtration of the resulting crystals
gave 0.395 g (72%) of cesium benzenecarbodithioate (5e) as dark red
1
red needles: mp 200-202 °C dec. IR (KBr): 1201 (νCSS) cm-1. H
NMR (CD3OD): δ 7.18-8.13 (m, 5H, Ar). 13C NMR (CD3OD): δ
127.5 (p-C), 127.7 (m-C), 130.2 (o-C), (ipso-C), 276.6 (CdS). Anal.
Calcd for C7H5S2Rb (238.70): C, 35.22; H, 2.11. Found: C, 34.93; H,
2.09.
Rubidium 2-Methylbenzenecarbodithioate (4f). Method B: brown
crystals [recrystallization from ethanol/ether (1:2) at -20 °C]. Mp:
1
237-239 °C dec. IR (KBr): 1023 (νCSS) cm-1. H NMR (CD3OD):
1
granulates. IR (KBr): 1201 (νCSS) cm-1. H NMR (DMSO-d6): δ
δ 2.42 (s, 3H, CH3), 7.00-7.14 (m, 4H, Ar). 13C NMR (CD3OD): δ
19.5 (CH3), 125,1, 126.0, 126.5, 130.8, 159.9 (Ar), 256.1 (CdS). Anal.
Calcd for C8H7S2Rb (252.72): C, 38.02; H, 2.79. Found: C, 37.76; H,
2.89.
7.15-8.14 (m, 5H, Ar). 13C (CD3OD): δ 126.0 (p-C), 126.2 (m-C),
127.8 (o-C), 152.8 (ipso-C), 250.5 (CdS).
Cesium 4-Methylbenzenecarbodithioate (5f). Method B: red
brown granulated crystals [recrystallization from ethanol/ether (1:1) at
-20 °C overnight]. Mp: 244-246 °C dec. IR (KBr): 1025 (νCSS)
Rubidium 4-Methylbenzenecarbodithioate (4g) Method B: red
brown crystals [recrystallization from ethanol/ether (1:2) at -20 °C].
Mp: 223-225 °C. IR (KBr): 1008 (νCSS) cm-1. 1H NMR (CD3OD):
δ 2.30 (s, 3H, CH3), 7.03 (d, 2H, Ar), 8.13 (d, 2H, Ar). 13C NMR
(CD3OD): δ 21.3 (CH3), 127.8 (p-C), 128.3 (m-C), 140.9 (o-C), 151.6
1
cm-1. H NMR (DMSO-d6): δ 2.30 (s, 3H, CH3), 7.01 (d, 2H, Ar),
8.09 (d, 2H, Ar). 13C NMR (DMSO-d6): δ 20.7 (CH3), 126.4 (p-C),
126.6 (m-C), 137.5 (o-C), 149.9 (ipso-C), 249.9 (CdS).

Heavy Alkali Metal Arenedithiocarboxylates
Inorganic Chemistry, Vol. 38, No. 3, 1999 505
Cesium 4-Methoxybenzenecarbodithioate (5g). Method B: red
granulated crystals [recrystallization from ethanol/ether (1:1) at -20
was slowly added at 0 °C, and the mixture was allowed to stand at
-20 °C. Removal of the resulting crystals by filtration gave 0.298 g
(69%) of tetramethylammonium 4-methylbenzenecarbodithioate (8e)
°C overnight]. Mp: 232-234 °C dec. IR (KBr): 1026 (νCSS) cm-1
.
1H NMR (DMSO-d6): δ 3.75 (s, 3H, OCH3), 6.70 (d, 2H, Ar), 8.33
(d, 2H, Ar). 13C NMR (DMSO-d6): δ 55.8 (CH3O), 111.0 (p-C), 128.2
(m-C), 145.0 (o-C), 160.2 (ipso-C), 248.0 (CdS).
as dark needles. Mp: 182-190 °C dec. IR (KBr): 1172 (νCSS) cm-1
.
1H NMR (CD3OD): δ 2.30 (s, 3H, CH3Ar), 3.12 (s, 12H, CH3N), 7.04
(d, J ) 8.2 Hz, 2H, Ar), 8.14 (d, J ) 8.2 Hz, 2H, Ar). 13C NMR (CD3-
OD): δ 21.2 (p-CH3), 55.9 (NCH3), 128.4, 128.9, 140.8, 151.8 (ipso-
C), 255.3 (CdS). UV/vis (EtOH): λmax [nm] (log ꢀ) 291 (4.08), 364
(3.84), 508 (2.18), 637 (0.76). Anal. Calcd for C12H19NS2 (241.41):
C, 59.70; H, 7.93. Found: C, 59.70; H, 7.84.
Cesium 4-Chlorobenzenecarbodithioate (5h). Method B: red
brown crystals [recrystallization from ethanol/ether (1:2) at -20 °C
1
for 15 h]. Mp 246-248 °C dec. IR (KBr): 1032 (νCSS) cm-1. H
NMR (DMSO-d6): δ 7.19 (d, 2H, Ar), 8.20 (d, 2H, Ar). 13C NMR
(DMSO-d6): δ 126.0 (p-C), 128.0 (m-C), 133.2 (o-C), 150.9 (ipso-C),
247.7 (CdS).
Tetramethylammonium 2-Methoxybenzenecarbodithioate (8f):
red crystals [recrystallization from acetonitrile/ether (2:1) at -20 °C]:
0.835 g (68%). Mp: 164-165 °C dec. IR (KBr): 1182, 1165 (νCSS)
Cesium 2,4,6-Trimethylbenzenecarbodithioate (5i). Method B:
reddish orange granulated crystals [recrystallization from ethanol/ether
(1:2) at -20 °C overnight]. Mp: 233-234 °C dec. IR (KBr): 1034
(νCSS) cm-1. 1H NMR (DMSO-d6): δ 2.16 (s, 6H, 2,6-CH3), 2.17 (s,
3H, 4-CH3), 7.19 (d, 2H, Ar), 8.20 (d, 2H, Ar). 13C (CD3OD): δ 18.8
(CH3), 18.9 (CH3), 127.2 (p-C), 128.4, 131.3 (o-C), 156.1 (ipso-C),
258.7 (CdS).
Reaction of Dithiocarboxylic Acids with Alkali and Alkali Earth
Metal Chlorides, Bromides, and Iodides or with Lithium and
Sodium Fluorides. General Procedures. 1-Methylethanecarbodithioic
acid (7 mmol) and alkali metal halogenides (LiF, NaF, KF, KCl, KBr,
KI, RbCl, RbBr, RbI, CsCl, CsBr, CsI) (4 mmol) or alkali earth metal
fluorides (CaF2, SrF2, BaF2) (3 mmol) were stirred in ether (1 mL) at
20 °C for 2 h. By filtration of the insoluble part and washing with
ether (3 × 3 mL), the alkali metal except for KF and alkali earth metal
halogenides were recovered in quantitative yield, respectively.
Tetramethylammonium Dithiocarboxylates. The preparation of
tetramethylammonium 4-methylbenzenecarbodithioate (8e) is shown
in detail as a typical procedure.
1
cm-1. H NMR (CD3OD): δ 3.17 (s, 3H, NMe), 3.79 (s, 3H, CH3O),
6.8-6.9 (m, 2H, Ar), 7.1-7.2 (m, 2H, Ar). 13C NMR (CD3OD): δ
56.0 (NCH3), 56.4 (CH3O), 112.9, 121.0, 127.1, 128.0, 152.0, 155.7
(Ar), 257.8 (CdS). UV/vis (EtOH): λmax [nm] (log ꢀ) 343 (3.34), 475
(2.95), 642 (2.94).
Tetramethylammonium 4-Methoxybenzenecarbodithioate (8g):
reddish orange crystals [recrystallization from acetonitrile/ether (1:1)
at -20 °C], 0.455 g (71%). Mp: 143-144 °C dec. IR (KBr): 1185,
1162 (νCSS) cm-1. 1H NMR (CD3OD): δ 3.13 (s, 3H, NMe), 3.81 (s,
3H, CH3O), 6.76 (d, J ) 8.8 Hz, 2H, Ar), 8.35 (d, J ) 8.8 Hz, 2H,
Ar). 13C NMR (CD3OD): δ 55.9 (NCH3), 55.9 (CH3O), 112.7, 130.0,
146.7, 163.1 (Ar), 253.4 (CdS). UV/vis (EtOH): λmax [nm] (log ꢀ) 234
(3.71), 320 (3.93), 489 (2.37), 620 (1.97) 645 (1.96).
Tetramethylammonium 4-Chlorobenzenecarbodithioate (8h):
reddish orange crystals [recrystallization from acetonitrile/ether (1:1)
at -20 °C], 0.745 g (39%). Mp: 165-170 °C dec. IR (KBr): 1157
(νCSS) cm-1. 1H NMR (CDCl3): δ 3.14 (s, 12H, NMe), 7.20 (d, J )
8.4 Hz, 2H, Ar), 8.18 (d, J ) 8.4 Hz, 2H, Ar). 13C NMR (CDCl3): δ
55.9 (NCH3), 127.7, 129.0, 136.2, 153.0 (Ar), 253.2 (CdS). UV/vis
(EtOH): λmax [nm] (log ꢀ) 367 (3.84), 477 (2.99), 506 (2.52), 636 (2.94).
Reaction of Alkali Metal Dithiocarboxylates with Methyl Iodide.
Typical Procedures. Rubidium 4-methylbenzenecarbodithioate (4g)
(0.270 g, 1.07 mmol) and methyl iodide (5.0 mL, 80.3 mmol) were
stirred at room temperature for 30 min. Filtration and evaporation of
the excess of methyl iodide under reduced pressure gave methyl
Tetramethylammonium Dithiopropanoate (8a): orange yellow
needles [recrystallization from acetonitrile/ether (1:2) at -20 °C], 0.276
1
g (64%). Mp: 145-150 dec. IR (KBr): 949, 778 (νCSS) cm-1. H
NMR (CD3OD): δ 1.34 (t, J ) 7.5 Hz, 3H, CH3), 3.12 (q, J ) 7.5 Hz,
2H, CH2), 3.27 (s, 12 Hz, NMe). 13C NMR (CD3OD): δ 17.3 (CH3),
55.8 (CH2), 56.0 (NMe), 269.8 (CdS). UV/vis (EtOH): λmax [nm] (log
ꢀ) 291 (4.08), 340 (4.27), 469 (2.81), 641 (2.77).
4-methylbenzenecarbodithioate (9) as a red oil. The IR and 1H and 13
C
Tetramethylammonium 1-Methyldithiobutanoate (8b): orange
yellow needle crystals [recrystallization from acetonitrile/ether (1:1)
at -20 °C], 0.409 g (76%). Mp: 168-173 °C dec. IR (KBr): 949, 867
NMR spectra were exactly consistent with those of an authentic sample
prepared by the reaction of cesium 4-methylbenzenecarbodithioate (5f)
with methyl iodide: red oil, 35% (0.069 g). IR (neat): 1245 (νCSS)
1
(νCSS) cm-1. H NMR (CD3OD): δ 1.21(d, J ) 6.8 Hz, 6H, CCH3),
1
cm-1. H NMR (CDCl3): δ 2.36 (s, 3H, CH3), 2.75 (s, 3H, SCH3),
3.23 (s, 12 Hz, NMe) 3.57 (sept, J ) 6.8 Hz, 1H, CH). 13C NMR (CD3-
OD): δ 25.3 (CH3), 56.0 (NMe), 58.1 (CH), 275.4 (CdS). UV/vis
(EtOH): λmax [nm] (log ꢀ) 271 (3.85), 340 (4.29), 469 (2.84), 640 (2.81).
Anal. Calcd for C8H19NS2 (193.36): C, 49.64; H, 9.84. Found: C,
49.69; H, 9.90.
7.20 (d, J ) 8.4 Hz, Ar), 7.93 (d, J ) 8.4 Hz, Ar). 13C NMR (CDCl3):
δ 20.5 (SCH3), 21.5 (CH3), 126.8, 129.0, 142.6, 142.3 (Ar), 228.6 (Cd
S). MS (CIDI) m/z (relative intensity, %): 183 [+] (100).
Reaction of Alkali Metal Dithiocarboxylates with Triorganotin
1
Chloride. Typical Procedures. The IR and H and 13C NMR spectra
Tetramethylammonium Benzenecarbodithioate (8c): reddish or-
ange crystals [recrystallization from acetonitrile/ether (5:6) at -20 °C],
of the tin esters 10a and 10b were exactly consistent with those of
authentic samples prepared by the reaction of piperidinium 4-methyl-
benzenecarbodithioate with trimethyltin and triphenyltin chlorides,
respectively.53,54
0.295 g (38%). Mp: 160-165 °C dec. IR (KBr): 1014 (νCSS) cm-1
.
1H NMR (CD3OD): δ 3.12 (s, 12H, NMe), 7.20 (t, J ) 7.6 Hz, 1H,
Ar), 7.22 (t, J ) 7.6 Hz, 2H, Ar), 8.13 (d, J ) 7.6 Hz, 2H, Ar). 13C
NMR (CD3OD): δ 55.9 (NCH3), 127.6, 127.8, 130.2, 154.8 (Ar), 256.0
(CdS). UV/vis (EtOH): λmax [nm] (log ꢀ) 276 (4.28), 361 (3.91), 502
(2.33).
Trimethyltin 4-Methylbenzenecarbodithioate (10a):53 dark red oil,
1
2
1
117
96%. H NMR (CDCl3): δ 0.69 (s, 9H, SnCH3, J H-
) 54 Hz,
Sn
2
1
119
J H-
) 57 Hz), 2.33 (s, 3H, CH3), 7.10 (d, J ) 8.4 Hz, 2H, Ar),
Sn
8.19 (d, J ) 8.4 Hz, 2H, Ar). 13C NMR (CDCl3): δ -2.75 (CH3,
1
1
1
Tetramethylammonium 2,4,6-Trimethylbenzenecarbodithioate
(8d): dark red crystals [recrystallization from acetonitrile/ether (1:1)
at -20 °C], 0.142 g (63%). Mp 190-192 °C. IR (KBr): 950, 880
1
117
119
J H-
) 359 Hz, J H-
) 374 Hz), 21.5 (SCH3), 127.3, 128.4,
Sn
Sn
143.0, 143.4 (Ar), 235.0 (CdS). 119Sn NMR (CDCl3): δ 51.2,
1
13
119
J
Sn) 376 Hz. UV/vis (CH2Cl2): λmax [nm] (log ꢀ) 314 (4.17),
C-
1
(νCSS) cm-1. H NMR (CDCl3): δ 2.20 (s, 3H, p-CH3Ar), 2.35 (s,
525 (1.99).
6H, o-CH3Ar), 3.19 (s, 12H, NMe), 6.73 (s, 2H, Ar). 13C NMR
(CDCl3): δ 19.4 (CH3), 21.0 (CH3), 55.9 (NCH3), 128.8, 130.2, 134.7,
156.8 (ipso-C, Ar), 271.3 (CdS). UV/vis (EtOH): λmax [nm] (log ꢀ)
252 (3.95), 343 (4.35), 475 (2.29), 641 (2.94).
Triphenyltin 4-Methylbenzenecarbodithioate (10b).54 Cesium
4-methylbenzenecarbodithioate (5f) (0.159 g, 0.53 mmol) and triphen-
yltin chloride (0.183 g, 0.47 mmol) were stirred in dichloromethane (3
mL) at 20 °C for 30 min. The insoluble part (excess 5f and CsCl) was
filtered out, and the solvent was evaporated, under reduced pressure.
Crystallization of the resulting red oil with ether (3 mL) and hexane (3
mL) gave 0.237 g (98%) of triphenyltin 4-methylbenzenecarbodithioate
Tetramethylammonium 4-Methylbenzenecarbodithioate (8e).
Sodium 4-methylbenzencarbodithioate (0.339 g, 1.78 mmol) and
tetramethylammonium chloride (0.19 g, 1.8 mmol) were stirred in
acetonitrile (15 mL) at 20 °C for 2 h. Removal of sodium chloride by
filtration and then evaporation of the filtrate under reduced pressure
gave a red pink solid as microcrystals. The solid was dissolved in
acetonitrile (5 mL), and then the mixture was filtered. Ether (8 mL)
(53) Kato, S.; Mizuta, M.; Ishii, Y. J. Organomet. Chem. 1973, 55, 121.
(54) Kato, S.; Kato, T.; Yamauchi, T.; Shibahashi, Y.; Kakuda, E.; Mizuta,
M.; Ishii, Y. J. Organomet. Chem. 1974, 76, 215.

506 Inorganic Chemistry, Vol. 38, No. 3, 1999
Kato et al.
(10b) as red brown crystals. The IR and 1H NMR spectra were
consistent with those of an authentic sample prepared by the reaction
of piperidinium 4-methylbenzenecarbodithioate with triphenyltin chlo-
ride. Mp 119 °C. IR (KBr): 1221 (CdS) cm-1. 1H NMR (CDCl3): δ
2.28 (s, 3H, CH3), 7.40 (m, 19H, Ar). 13C NMR (CDCl3): δ 21.5 (CH3),
127.6, 128.0, 128.8, 129.6, 130.7, 139.5, 141.4, 144.2 (Ar), 232.1 (Cd
Priority Areas (10133221) provided by the Ministry of Educa-
tion, Science, Sports and Culture, Japan. We thank Prof. Takashi
Kawamura of Gifu University for invaluable assistance with
crystallography.
Supporting Information Available: X-ray structural information
for the compounds 3b, 4g, 5f, 7g, 8e, and 8f in Table 3 including atomic
coordinates, isotropic thermal parameters, and complete bond distances
and angles. This material is availabe free of charge via the Internet at
http://pubs.acs.org.
1
S). 119Sn NMR (CDCl3): δ -138.8 ( J
Sn ) 594 Hz). UV/vis (CH2-
13
119
C-
Cl2): λmax [nm] (log ꢀ) 328 (4.51), 504 (2.39).
Acknowledgment. This work was supported by a Grant-
in-Aid for Scientific and Development Research (09355032)
and partially by a Grant-in-Aid for Scientific Research on
IC9808089