Mixed-ligand complexes of cadmium(II) containing bulky polydentate nitrogen-based ligands

Article abstract of DOI:10.1016/S0020-1693(02)00735-1

The reaction of equimolar amounts of CdCl₂, Tl[H ₂B(3-Bu^tpz)₂] (pz=pyrazolyl ring) and Na[Et₂NCS₂] yields [H₂B(3-Bu ^tpz)₂]Cd(S₂CNEt₂) (1) and a similar reaction using Tl[HB(3-Bu^tpz)₃] yields [HB(3-Bu ^tpz)₃]Cd(S₂CNEt₂) (2). The solid state structure of [HB(3-Bu^tpz)₃]Cd(S₂CNEt ₂) shows the arrangement of the donor atoms is a distorted trigonal bipyramid, an unusual geometry for a molecule containing a tridentate [HB(3-Bu^tpz)₃]^- ligand. Mixing CdCl ₂ with 2 equiv. of MeLi yields the Me₂Cd intermediate that reacts with Tl[HB(3-Phpz)₃] to yield [HB(3-Phpz) ₃]CdCH₃ (3). Compound 3 reacts with thiotoluene to yield [HB(3-Phpz)₃]CdS(p-C₆H₄CH₃) (4) and mercaptopyridine to yield [HB(3-Phpz)₃]Cd(SNC₆H ₄) (5). The neutral 2,6-bis(2,6-dimethylphenylimino)pyridine ligand (pydim) reacts with CdCl₂ in equimolar amounts to yield the adduct (pydim)CdCl₂ (6). The cadmium(II) is in a five-coordinate arrangement that is best described as a distorted trigonal bipyramid. The three nitrogen atoms of the planar pyridine ligand occupy an equatorial and both axial sites, but the intrinsic bite angle of the ligand forces a significant distortion in the axial bond angle. Compound 6 reacts with an equimolar amount of Na[Et₂NCS₂] to yield [(pydim)Cd(S₂CNEt ₂)][Cl] (7). The reaction of equimolar amounts of pydimMe ₂ and Cd(NO₃)₂ yields (pydimMe ₂)Cd(NO₃)₂ (8). In the structure of this complex, one nitrate ligand is bidentate and the other monodentate. If the bidentate ligand is considered as occupying one site of a polyhedron, the structure of 8 can be considered as a trigonal bipyramid, very similar to that of 6.

Full text of DOI:10.1016/S0020-1693(02)00735-1

Inorganica Chimica Acta 334 (2002) 1Á9
/
www.elsevier.com/locate/ica
Mixed-ligand complexes of cadmium(II) containing bulky
polydentate nitrogen-based ligands
Daniel L. Reger *, Terri D. Wright, Mark D. Smith
Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
Received 20 June 2001; accepted 8 October 2001
Dedicated to Andy Wojcicki on the occasion of his retirement from Ohio State University
Abstract
The reaction of equimolar amounts of CdCl2, Tl[H2B(3-Butpz)2] (pzꢀ
/pyrazolyl ring) and Na[Et2NCS2] yields [H2B(3-
Butpz)2]Cd(S2CNEt2) (1) and a similar reaction using Tl[HB(3-Butpz)3] yields [HB(3-Butpz)3]Cd(S2CNEt2) (2). The solid state
structure of [HB(3-Butpz)3]Cd(S2CNEt2) shows the arrangement of the donor atoms is a distorted trigonal bipyramid, an unusual
geometry for a molecule containing a tridentate [HB(3-Butpz)3]ꢁ ligand. Mixing CdCl2 with 2 equiv. of MeLi yields the Me2Cd
intermediate that reacts with Tl[HB(3-Phpz)3] to yield [HB(3-Phpz)3]CdCH3 (3). Compound 3 reacts with thiotoluene to yield
[HB(3-Phpz)3]CdS(p-C6H4CH3) (4) and mercaptopyridine to yield [HB(3-Phpz)3]Cd(SNC6H4) (5). The neutral 2,6-bis(2,6-
dimethylphenylimino)pyridine ligand (pydim) reacts with CdCl2 in equimolar amounts to yield the adduct (pydim)CdCl2 (6).
The cadmium(II) is in a five-coordinate arrangement that is best described as a distorted trigonal bipyramid. The three nitrogen
atoms of the planar pyridine ligand occupy an equatorial and both axial sites, but the intrinsic bite angle of the ligand forces a
significant distortion in the axial bond angle. Compound 6 reacts with an equimolar amount of Na[Et2NCS2] to yield
[(pydim)Cd(S2CNEt2)][Cl] (7). The reaction of equimolar amounts of pydimMe2 and Cd(NO3)2 yields (pydimMe2)Cd(NO3)2 (8).
In the structure of this complex, one nitrate ligand is bidentate and the other monodentate. If the bidentate ligand is considered as
occupying one site of a polyhedron, the structure of 8 can be considered as a trigonal bipyramid, very similar to that of 6. # 2002
Elsevier Science B.V. All rights reserved.
Keywords: Tris(pyrazolyl)borate ligand; Cadmium(II); 2,6-Bis(2,6-dimethylphenylimino)pyridine ligand
1. Introduction
correlations [1Á3]. Our current investigations exploit the
/
useful properties of poly(pyrazolyl)borate ligands
through the preparation of monomeric cadmium(II)
complexes in which the primary donor atom set can be
controlled in a systematic manner and serve as model
analogues for many metalloproteins and enzymes such
as zinc fingers [4].
The versatility of the poly(pyrazolyl)borate ligands is
not only found in the ability to prepare both bidentate
and tridentate ligands, but also in the variability of the
substituents on the pyrazolyl rings [5]. We are presently
exploring the chemistry of poly(pyrazolyl)borate ligands
that are substituted at the 3-position of the pyrazolyl
rings with the tert-butyl and phenyl groups (Scheme 1).
Because we are interested in studying monomeric
complexes of cadmium(II), the high steric bulk of these
ligands should prevent any oligomerization or solvent
We have been preparing both homoleptic and mixed
ligand poly(pyrazolyl)borate complexes of cadmium(II)
and investigating their solution and solid state 113Cd
NMR [1]. This study is important because cadmium has
two isotopes that are NMR active with spinꢀ1/2
/
allowing 113Cd NMR to be used as a ‘spin spy’ in the
study of zinc containing proteins. The strategy here is to
replace the zinc, a metal with few good spectroscopic
handles, with cadmium and use NMR to explore
structure/shielding relationships and how such relation-
ships may be useful in uncovering structure and function
* Corresponding author. Tel.: ꢂ
9521.
E-mail address: reger@psc.sc.edu (D.L. Reger).
/
1-803-777 2587; fax: ꢂ1-803-777
/
0020-1693/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 0 - 1 6 9 3 ( 0 2 ) 0 0 7 3 5 - 1

2
D.L. Reger et al. / Inorganica Chimica Acta 334 (2002) 1Á9
/
broadband probe, and the chemical shifts are reported
in parts per million versus external 0.1 M Cd(ClO4)2.
Mass spectral data were recorded on a VG 70SQ
spectrometer mass spectrometer using electron impact
ionization and FABS. Clusters assigned to specific ions
show appropriate isotopic patterns as calculated for the
atoms present. Elemental analyses were performed by
Robertson Microlit Laboratories. Infrared spectra were
recorded on a PerkinÁ
Anhydrous CdCl2, Cd(NO)3×
were purchased from Aldrich Chemicals. Tl[H2B(3-
Butpz)2], Tl[HB(3-Butpz)3], Tl[HB(3-Phpz)3] (pzꢀ
pyr-
/
Elmer 781 spectrophotometer.
/4H2O, and Na[S2NCEt2]
/
azolyl ring), and 2,6-bis[(2,6-dimethylphenylimino)-
methyl]pyridine (pydim) and 2,6-bis[1-(2,6-dimethylphe-
nylimino)ethyl]pyridine (pydimMe2) were prepared ac-
cording to published methods. [6,7]
Note: Cadmium and thallium compounds and their
wastes are extremely toxic and must be handled care-
fully.
Scheme 1.
coordination problems that have had an effect on
previous NMR studies [4].
We are also using the neutral, bulky ligand 2,6-
bis(2,6-dimethylphenylimino)pyridine (pydim) (Scheme
2). This planar, substituted pyridine ligand was chosen
to contrast the tripodal, facial coordination of tris(pyr-
azolyl)borate ligands.
2.2. [H2B(3-Butpz)2]Cd(S2CNEt2) (1)
CdCl2 (0.18 g, 1.0 mmol) and Tl[H2B(3-Butpz)2] (0.46
g, 1.0 mmol) were charged into a round bottom Schlenk
flask and dissolved in THF (15 ml). This solution was
allowed to stir for 2 h at room temperature (r.t.).
Na[Et2NCS2] (0.20 g, 1.0 mmol) was dissolved in THF
(10 ml) and added to the cadmium solution. This
solution was allowed to stir for 3 h at r.t. The volatiles
were removed in vacuo and the remaining solid was
extracted with toluene (25 ml). The mixture was filtered
and the solvent evaporated to dryness to leave a pale
Outlined here are the syntheses, solid state structures
and solution 113Cd NMR of mixed ligand compounds of
cadmium(II) containing either a poly(pyrazolyl)borate
or pydim ligand and a second ligand containing sulfur
donor atoms, as well as starting materials for the
syntheses of these compounds.
2. Experimental
yellow powder (0.17 g, 0.33 mmol, 33%); melting point
1
2.1. General procedure
(m.p.)ꢀ
/
170Á
/
172 8C (dec.). H NMR (CDCl3): d 7.45,
6.02 (2, 2; br, br; 4,5-H pz); 3.88 (4, q, Jꢀ
/
7.1 Hz, CH2);
All operations were carried out under a nitrogen
atmosphere using standard Schlenk techniques and a
Vacuum Atmospheres HE-493 dry box. All solvents
1.38 (18, s, C(CH3)3); 1.32 (6, t, Jꢀ
/
7.1 Hz, CH2CH3).
13C NMR (CDCl3): d 162.3, 136.4 (3,5-C pz); 101.8 (4-C
pz); 50.8 (CH2); 31.7 (C(CH3)3); 30.9 (C(CH3)3); 12.1
(CH2CH3). 113Cd NMR (CDCl3): d 263. IR (Nujol
1
were dried, degassed, and distilled prior to use. The H
mull, cmꢁ1): n BÃ
/
H 2430. Accurate MS; m/z (Mꢂ):
NMR spectra were recorded on a Varian AM300 or
AM400 spectrometer using a broadband probe. Proton
chemical shifts are reported in parts per million (ppm)
versus internal Me4Si. 113Cd NMR spectra were re-
corded on a Bruker AM 500 spectrometer using a 5-mm
calc. for [H2B(3-Butpz)2](S2CNEt2)113Cd, 520.1294.
Found, 520.1304.
2.3. [HB(3-Butpz)3]Cd(S2CNEt2) (2)
CdCl2 (0.18 g, 1.0 mmol) and Tl[HB(3-Butpz)3] (0.57
g, 1.0 mmol) were charged into a round bottom Schlenk
flask and dissolved in THF (15 ml). This solution was
allowed to stir for 2 h at r.t. Na[Et2NCS2] (0.20 g, 1.0
mmol) was dissolved in THF (10 ml) and added to the
cadmium solution. This solution was allowed to stir for
3 h at r.t. The volatiles were removed in vacuo and the
remaining solid was extracted with toluene (25 ml). The
mixture was filtered and the solvent evaporated to
dryness to leave a pale yellow powder (0.24 g, 0.37
mmol, 37%). Crystals suitable for X-ray analysis were
Scheme 2.

D.L. Reger et al. / Inorganica Chimica Acta 334 (2002) 1Á
/9
3
obtained by layering a CH2Cl2 solution with hexanes.
1H NMR (CDCl3): d 7.57, 6.07 (3, 3; d, d; Jꢀ
2.2 Hz,
Jꢀ2.2 Hz; 4,5-H pz); 3.93 (4, q, Jꢀ7.1 Hz, CH2);
1.44 (27; s; C(CH3)3); 1.33 (6, t, Jꢀ7.1 Hz,
CH2CH3). 113Cd NMR (CDCl3): d 253. IR (Nujol
d 232 accurate MS; m/z (Mꢂ): calc. for [HB(3-
/
Phpz)3]113Cd(SNC6H4), 665.1108. Found, 665.1103.
/
/
/
2.7. (pydim)CdCl2 (6)
mull, cmꢁ1): n BÃ
/
H 2506. Accurate MS; m/z (Mꢂ):
CdCl2 (0.18 g, 1.0 mmol) and 2,6-bis[(2,6-dimethyl-
phenylimino)methyl]pyridine (0.36 g, 1.0 mmol) were
placed in a round bottom Schlenk flask. 1-Butanol (25
ml) was added via syringe. The solution was allowed to
stir and heated to 80 8C for 0.5 h. The solvent was
removed under reduced pressure to afford a yellow solid
calc. for [HB(3-Butpz)3]113Cd(S2CNEt2), 639.2223.
Found, 639.2222.
2.4. [HB(3-Phpz)3]CdCH3 (3)
(0.49 g, 0.91 mmol, 91%); m.p.ꢀ
ray quality crystals were obtained by layering an acetone
1
solution with hexane. H NMR (acetone-d6), d: 8.93 (2,
/
254Á260 8C (dec.). X-
/
CdCl2 (0.25 g, 1.4 mmol) was suspended in Et2O (20
ml) and cooled to ꢁ78 8C. CH3Li (2.0 ml, 1.4 M, 2.8
/
mmol) was added via syringe and the solution allowed
to warm to r.t. (1 h). A solution of Tl[HB(3-Phpz)3]
(0.74 g, 1.2 mmol) in THF was added via cannula and
the resulting black solution stirred for 2 h. The solvent
was removed under vacuum and the resulting black
solid was extracted with benzene (25 ml) and filtered.
The benzene was removed under vacuum to afford a
white solid. This solid was extracted with toluene (20
ml), filtered, and the solvent evaporated to yield a white
s, JCdH
Jꢀ7.7 Hz, 3,5-H py); 7.06 (6, m, 3,4,5-H ph); 2.32 (12,
s, CH3). FABꢂ MS; m/z: 490 (MÃCl). Accurate ESꢂ/
MS (MÃ 490.0612.
Clꢂ) calc. for [(pydim)CdCl]ꢂ
Found, 490.0620.
ꢀ
/
20.5 Hz, Ä/CH); 8.74 (1, m, 4-H py); 8.50 (2, d,
/
/
/
,
2.8. [(pydim)Cd(S2CNEt2)][Cl] (7)
(Pydim)CdCl2 (0.26 g, 0.50 mmol) and Na[Et2NCS2]
(0.09 g, 0.50 mmol) were charged into a round bottom
flask and dissolved in THF (20 ml). The mixture was
allowed to stir for 4 h. The solvent was removed in
vacuo to leave a yellow solid. The solid was extracted
with toluene and filtered. The clear yellow solution was
evaporated to yield a yellow solid (0.21 g, 0.35 mmol,
solid (0.28 g, 0.49 mmol, 41%); m.p.ꢀ
/
179Á
(dec.). H NMR (CDCl3): d 7.79 (3, d, Jꢀ2.2 Hz, 5-H
pz); 7.66, 7.36 (6, 9; d of d, m; C6H5pz); 6.45 (3, d, Jꢀ
2.2 Hz, 4-H pz); ꢁ0.418 (3, s, JCdH 80.4 Hz, CH3).
113Cd NMR (CDCl3): d 380. IR (Nujol mull, cmꢁ1): n
CH3). Anal.
/
185 8C
1
/
/
/
ꢀ
/
BÃ
/
H 2503. MS; m/z: 569 (MÃ
/
H), 555 (MÃ
/
Calc. for [HB(3-Phpz)3]CdCH3: C, 58.94; H, 4.38; N,
14.73. Found: C, 58.46; H, 4.26; N, 14.09%.
70%); m.p.ꢀ
d6): d 8.47 (2, d, Jꢀ
8.22 (1, t, Jꢀ7.7 Hz, 4-H py); 7.11 (4, d, Jꢀ
/
237Á
/
240 8C (dec.). 1H NMR (d, (acetone-
7.7 Hz, 3,5-H py); 8.45 (s, 2, CH);
7.4 Hz, 3,5-
/
/
/
2.5. [HB(3-Phpz)3]CdS(p-C6H4CH3) (4)
H ph); 6.99 (2, t, Jꢀ7.4 Hz, 4-H ph); 2.15 (12, s, CH3).
/
FABꢂ accurate MS; m/z (Mꢂ): calc. for [pydimCd-
(S2CNEt2)]ꢂ, 599.1177. Found 599.1181.
[HB(3-Phpz)3]CdCH3 (0.28 g, 0.50 mmol) and p-
thiotoluene (0.060 g, 0.50 mmol) were charged into a
Schlenk round bottom flask. THF (20 ml) was added via
syringe. The solution was allowed to stir 24 h at r.t. The
solvent was removed in vacuo to leave a white powder
2.9. (pydimMe2)Cd(NO3)2 (8)
Cd(NO)3×/4H2O (0.31 g, 1.01 mmol) and 2,6-bis[1-
(0.13 g, 0.19 mmol, 39%); m.p.ꢀ
(CDCl3): d 7.77 (3, d, Jꢀ2.2 Hz, 5-H pz); 7.66 (15, m,
C6H5 pz); 7.27 (4, m, C6H4); 6.42 (3, d, Jꢀ2.2 Hz, 4-H
/
140Á
/
146 8C. 1H NMR
(2,6-dimethylphenylimino)ethyl]pyridine (0.33 g, 0.88
mmol) were dissolved in MeOH (20 ml) and stirred for
0.5 h at 20 8C. The solvent was removed to leave a
/
/
pz). Accurate MS; m/z (Mꢂ): calc. for [HB(3-
yellow solid (0.49 g, 0.81 mmol, 81%); m.p.ꢀ
/
280Á
/
Phpz)3]113CdS(p-C6H4CH3),
674.1291.
674.1312.
Found,
285 8C (dec.). X-ray quality crystals were grown by
layering a CH2Cl2 solution with hexanes. 1H NMR
(acetone-d6): d 8.66 (3, m, 3,4,5-H py); 6.98 (6, m, 3,4,5-
2.6. [HB(3-Phpz)3]Cd(SNC6H4) (5)
H ph); 2.68 (6, s, Ä
/
CCH3); 2.44 (12, s, CH3). Accurate
ESꢂ/MS (MÃNO3ꢂ): calc. for [(pydimMe2)Cd(NO3)]ꢂ,
545.1113. Found, 545.1120.
/
[HB(3-Phpz)3]CdCH3 (0.28 g, 0.50 mmol) and mer-
captopyridine (0.050 g, 0.50 mmol) were charged into a
Schlenk round bottom flask. THF (20 ml) was added via
syringe. The solution was allowed to stir 24 h at r.t. The
solvent was removed in vacuo to leave a yellow powder
2.10. X-ray crystal determination
Crystal data and details of data collection are given in
Table 1. A colorless plate crystal of 2 and small yellow
crystals of 6 and 8 were epoxied onto the end of a thin
glass fiber. X-ray intensity data were measured at 293 K
(0.18 g, 0.27 mmol, 54%); m.p.ꢀ
/
128Á
135 8C. 1H NMR
(CDCl3): d 8.42 (4, m, py); 7.56 (3, br, 5-H pz); 7.33 (15,
/
m, C6H5pz); 6.71 (3, m, 4-H pz). 113Cd NMR (CDCl3):

4
D.L. Reger et al. / Inorganica Chimica Acta 334 (2002) 1Á9
/
Table 1
Crystal data and structure refinement parameters for [HB(3-Butpz)3]Cd(S2CNEt2) (2), (pydim)CdCl2×(CH3)2CO (6), and (pydim-
Me2)Cd(NO3)2×CH2Cl2 (8)
2
6
8
Empirical formula
Formula weight (g molꢁ1
Temperature (K)
C26H44BCdN7S2
642.01
293(2)
C26H29CdCl2N3O
582.82
293(2)
C26H29CdCl2N5O6
690.84
173(2)
)
˚
Wavelength (A)
0.71073
orthorhombic
P21/n
0.71073
monoclinic
P21/n
0.71073
monoclinic
P21/c
Crystal system
Space group
Unit cell dimensions
˚
a (A)
9.8905(10)
10.4534(10)
17.5222(12)
90
13.035(4)
15.349(4)
13.707(4)
90
10.0875(7)
6.2659(11)
17.5222(12)
90
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
94.423(2)
90
106.298(5)
90
90.6990(10)
90
3
V (A )
˚
3206.3(5)
4
1.330
2632.2(12)
4
1.471
2874.9(3)
4
1.596
Z
Dcalc (mg mꢁ3
Absorption coefficient
)
0.838
1.055
0.994
(mmꢁ1
F(000)
)
1336
0.36ꢃ0.19ꢃ0.02
1184
0.08ꢃ0.03ꢃ0.02
1400
0.40ꢃ0.16ꢃ0.08
Crystal size (mm3)
Theta range for data collec- 1.31Á
/26.41
1.91Á
/
23.28
1.71Á26.40
/
tion (8)
Index ranges
ꢁ125h 512, ꢁ125k 513,
ꢁ385l 538
28 397
145h 59, ꢁ165k 516,
ꢁ155l 515
12 587
125h 512, ꢁ175k 520,
ꢁ215l 521
19 034
Reflections collected
Independent reflections
Completeness to theta
Data/restraints/parameters
Final R indices [I ꢀ2s(I)]
Goodness-of-fit on F2
6538 [Rintꢀ0.0384]
26.418, 99.6%
6538/1/348
3778 [Rintꢀ0.1276]
23.288, 99.6%
3778/0/304
5876 [Rintꢀ0.0390]
26.408, 99.7%
5876/0/367
R1ꢀ0.0490, wR2ꢀ0.1241
1.064
R1ꢀ0.0424, wR2ꢀ0.0675
0.984
R1ꢀ0.0391, wR2ꢀ0.0982
1.023
for 2 and 6 and 173 K for 8 using a Bruker SMART
APEX CCD-based diffractometer system using Mo Ka
all three, analysis of the data showed negligible crystal
decay during data collection and an empirical absorp-
tion correction based on the multiple measurement of
equivalent reflections was applied with the program
SADABS. The structures were solved by a combination of
direct methods and difference Fourier syntheses, and
refined by full-matrix least-squares against F2, using the
SHELXTL software package. All non-hydrogen atoms
were refined with anisotropic displacement parameters;
hydrogen atoms were placed in idealized positions and
refined using a riding model.
˚
0.71073 A). The crystal-to-detector dis-
radiation (lꢀ
/
tance was 5 cm. The unit cell was initially determined
based on reflections harvested from a set of three scans
measured in orthogonal wedges of reciprocal space.
Subsequently, a full sphere of data was collected with a
scan width of 0.38 in v and an exposure time of 30 s per
frame. The first 50 frames were re-collected at the end of
data set to monitor crystal decay. The raw data frames
were integrated with the SAINT
ꢂ program using a
/
narrow-frame integration algorithm. Corrections for
Lorentz and polarization effects were also applied by
SAINT. Systematic absences in the reflection data for 2
were consistent with the space group P21/n, which was
confirmed by successful solution and refinement of the
structure. Systematic absences in the data for 6 were
uniquely consistent with the monoclinic space group
P21/n with one molecule of acetone of crystallization.
The small size and low diffracting power of the crystal is
reflected in the high Rint and low percentage of observed
data. Compound 8 is in the space group P21/c as
determined by the systematic absences in the intensity
data with a molecule of CH2Cl2 of crystallization. For
3. Results and discussion
3.1. Tris(pyrazolyl)borate chemistry
The reaction of equimolar amounts of CdCl2,
Tl[H2B(3-Butpz)2] and Na[Et2NCS2] in THF at ambient
temperature yields [H2B(3-Butpz)2]Cd(S2CNEt2) (1).
This compound was characterized by NMR and high
resolution mass spectroscopy. It is air stable in the solid-
state and soluble in acetone, CH2Cl2, toluene, and
benzene.

D.L. Reger et al. / Inorganica Chimica Acta 334 (2002) 1Á
/9
5
Table 2
˚
Selected bond distances (A) and bond angles (8) for [HB(3-
Butpz)3]Cd(S2CNEt2) (2)
Bond distances
CdÃN(11)
CdÃN(21)
CdÃN(31)
CdÃS(1)
CdÃS(2)
S(2)ÃN(1)
BÃN(12)
2.360(3)
2.332(3)
2.311(3)
BÃN(32)
N(11)ÃN(12)
N(21)ÃN(22)
1.549(6)
1.374(4)
1.363(4)
1.373(4)
1.738(4)
1.323(5)
1.539(6)
2.5514(12) N(31)ÃN(32)
2.6766(12) S(1)ÃN(1)
1.699(4)
1.519(5)
N(1)ÃC(1)
BÃN(22)
Bond angles
N(11)ÃCdÃN(21)
N(11)ÃCdÃN(31)
N(21)ÃCdÃN(31)
N(11)ÃCdÃS(1)
N(21)ÃCdÃS(1)
N(31)ÃCdÃS(1)
N(11)ÃCdÃS(2)
N(21)ÃCdÃS(2)
82.33(11) N(31)ÃCdÃS(2)
80.74(11) N(1)ÃS(1)ÃCd
95.95(11) N(1)ÃS(2)ÃCd
98.39(8)
87.95(15)
84.71(15)
68.62(4)
118.2(2)
120.9(3)
120.9(3)
110.1(2)
The reaction of equimolar amounts of CdCl2,
Tl[HB(3-Butpz)3], and Na[S2CNEt2] in THF at ambient
temperature yields [HB(3-Butpz)3]Cd(S2CNEt2) (2).
Complex 2 is air stable in the solid and solution states
and soluble in acetone, halocarbons, and aromatic
solvents.
111.45(7)
127.57(9)
135.28(9)
178.84(8)
98.54(9)
S(1)ÃCdÃS(2)
S(2)ÃN(1)ÃS(1)
C(1)ÃN(1)ÃS(1)
C(1)ÃN(1)ÃS(2)
N(12)ÃN(11)ÃCd
bipyramid with S(2) and N(11) in the axial sites. The
S(2)ÃCdÃN(11) angle is 178.84(8)8 and these two donor
atoms make the longer bond distances to the cadmium.
The S(1)ÃCdÃS(2) bond angle is restricted to 68.62(4)8
by the chelate ring. The geometry in the equatorial plane
N(31) angle restrained to
/
/
/
/
is distorted by a N(21)Ã
/
CdÃ
/
95.95(11)8 by the chelate ring, but within the [HB(3-
Butpz)3]ꢁ ligand this angle is much larger than the
others giving a large spread on the NÃ
/
CdÃ
/
N bond
CdÃ
angles of 15.28. Interestingly, the average NÃ
/
/
N
bond angle of 86.38 is the same as with [HB(3,5-
Me2pz)3]Cd(S2CNEt2) where the spread is only 5.58
The solid state structure of [HB(3-Butpz)3]Cd(S2C-
NEt2) has been determined crystallographically. An
ORTEP diagram is shown in Fig. 1 and Table 2 shows
selected bond angles and distances. The arrangement of
the donor atoms is best viewed as a distorted trigonal
[1c]. The three CdÃ
/
N bond distances are very similar,
˚
varying only by 0.05 A, with an average CdÃ
/
N distance
of 2.33 A, just slightly longer than that observed with
˚
˚
[HB(3,5-Me2pz)3]Cd(S2CNEt2) (2.30 A). The S(1)Ã
/
CdÃ
/
N(31) angle is large for a trigonal bipyramid at
135.28(9)8. Although the dithiocarbamate ligand is
between being anisobidentate and symmetrically bonded
˚
with one longer (2.6766(12) A) and one shorter
˚
(2.5514(12) A) CdÃ
/
S bond distance, complex 2 is clearly
a five-coordinate species. The large size of cadmium
allows this geometry even though the [HB(3-Butpz)3]ꢁ
is known as a ‘tetrahedral enforcer’ [6]. Parkin has
reported previously the structure of [HB(3-But-5-
Mepz)3]Cd(k2-O2NO) [8], with a symmetrically bonded
k2-O2NO ligand, that could be considered a five-
coordinate complex. In this case, the k2-O2NO ligand
occupies less of the total coordination sphere, with the
OÃ
/
CdÃO angle restricted to 48.1(3)8, such that this
/
complex could be argued to be more like a four-
coordinate rather than a five-coordinate complex.
In order to prepare complexes with a central core of
N3CdS and N4CdS, [HB(3-Phpz)3]CdCH3 (3) was pre-
pared as a reactive precursor. Mixing CdCl2 with 2
Fig. 1. ORTEP diagram of [HB(3-Butpz)3]Cd(S2CNEt2) (2).
equivalents of MeLi in diethyl ether at ꢁ78 8C yielded
/

6
D.L. Reger et al. / Inorganica Chimica Acta 334 (2002) 1Á9
/
the Me2Cd intermediate that reacts with Tl[HB(3-
Phpz)3] in THF to yield 3. In this second stage of the
reaction, an immediate deposit of thallium metal is
observed that results from the decomposition of an
unstable (TlR) species [9]. The solid is air stable and
soluble in THF, Et2O, halocarbons, and aromatic
solvents. The presence of the CH3 group was confirmed
1
H coupling observed by H.
by characteristic CdÃ
/
Fig. 2. ORTEP diagram of (pydim)CdCl2 (6).
Mixing 3 with an equimolar amount of thiotoluene in
THF displaces the alkyl group, forming methane gas
and [HB(3-Phpz)3]CdS(p-C6H4CH3) (4).
Fig. 3. ORTEP diagram of (pydimMe2)Cd(NO3)2 (8).
Table 3
˚
Selected bond distances (A) and bond angles (8) for (pydim)CdCl2 (6)
This complex is air stable. Attempts to grow crystal-
lographic quality crystals of this compound yielded the
homoleptic [HB(3-Phpz)3]2Cd, a common product in the
careful crystallization of mixed-ligand complexes con-
taining the [HB(3-Phpz)3]ꢁ ligand.
The reaction of mercaptopyridine with the cadmium-
alkyl compound 3 in THF at ambient temperature
produces [HB(3-Phpz)3]Cd(SNC6H4) (5). This air stable
complex was characterized by NMR and high resolution
mass spectroscopy. However, crystals suitable for X-ray
analysis were not obtained.
Bond distances
CdÃCl(1)
CdÃCl(2)
CdÃN(1)
CdÃN(2)
CdÃN(3)
N(1)ÃC(1)
2.413(3)
2.394(3)
2.504(7)
2.261(7)
2.423(6)
1.447(10)
N(1)ÃC(9)
N(2)ÃC(10)
N(2)ÃC(14)
N(3)ÃC(15)
N(3)ÃC(16)
1.240(10)
1.334(10)
1.338(9)
1.265(10)
1.434(10)
Bond angles
N(2)ÃCdÃCl(2)
Cl(2)ÃCdÃCl(1)
Cl(2)ÃCdÃN(3)
N(2)ÃCdÃN(1)
Cl(1)ÃCdÃN(1)
C(9)ÃN(1)ÃC(1)
C(1)ÃN(1)ÃCd
C(10)ÃN(2)ÃCd
C(15)ÃN(3)ÃCd
125.68(18) N(2)ÃCdÃCl(1)
120.09(10) N(2)ÃCdÃN(3)
95.05(18) Cl(1)ÃCdÃN(3)
114.17(18)
70.0(2)
107.75(17)
105.23(19)
138.0(2)
112.8(6)
117.8(7)
119.8(6)
126.9(6)
68.2(2)
Cl(2)ÃCdÃN(1)
93.40(17) N(3)ÃCdÃN(1)
121.4(8)
125.3(6)
122.1(5)
113.1(5)
C(9)ÃN(1)ÃCd
C(10)ÃN(2)ÃC(14)
C(14)ÃN(2)ÃCd
C(16)ÃN(3)ÃCd
3.2. 2,6-Bis(2,6-dimethylphenylimino)pyridine chemistry
Three new cadmium complexes have been prepared
using the neutral pydim ligand. In contrast to the

D.L. Reger et al. / Inorganica Chimica Acta 334 (2002) 1Á
/9
7
An ORTEP drawing of 6 is shown in Fig. 2 and Table 3
shows selected bond angles and distances. The molecule
is monomeric with the cadmium ion in a five-coordinate
arrangement that is best described as a distorted trigonal
bipyramid. The three nitrogen atoms of the planar
pyridine ligand occupy an equatorial and both axial
sites, but the intrinsic bite angle of the ligand coupled
with the large size of the cadmium(II) force a significant
distortion in the axial bond angle of 138.0(2)8 and two
of the axial-equatorial angles where the (imino)NÃ
/
CdÃ
/
N(py) angles are restricted to 68.2(2) and 70.0(2)8. The
˚
N(py) bond (2.261(7) A) is significantly shorter
CdÃ
than the CdÃ
CdÃCl angle is 120.09(10)8. A fairly similar structure of
/
˚
/
N(imino) bonds (average 2.46 A). The ClÃ
/
/
tripodal pyrazolylborate ligands, this tridentate ligand
binds to the metal in a planar fashion. Reaction of the
pydim ligand with CdCl2 in equimolar amounts yields
a zinc analogue has been reported previously [10].
The (pydim)CdCl2 adduct reacts with an equimolar
amount of Na[Et2NCS2] in THF to yield [(py-
dim)Cd(S2CNEt2)][Cl] (7). This complex did not show
1
the adduct (pydim)CdCl2 (6). The H NMR spectrum
shows that the imino hydrogen atoms are coupled to
a mass spectrum by conventional direct probe metho-
dology, but did show a correct high resolution peak for
[(pydim)Cd(S2CNEt2)]ꢂ using FABꢂ techniques, indi-
cating the ionic nature of the compound. This complex
cadmium (Jꢀ/20.5 Hz). This complex is air stable and
moderately soluble in THF, acetone, and CH2Cl2.

8
D.L. Reger et al. / Inorganica Chimica Acta 334 (2002) 1Á9
/
Table 4
and distances. In the structure, one nitrate ligand is
bidentate with unequal CdÃO bond distances of
2.490(3) and 2.272(3) A, and the other monodentate
˚
Selected bond distances (A) and bond angles (8) for (pydim-
Me2)Cd(NO3)2 (8)
/
˚
˚
with a CdÃ
/
O bond distance of 2.248(2) A. The OÃ
/
CdÃ
/
Bond distances
O bond angle for the bidentate ligand is 53.18(10)8. If
one considers this ligand as occupying one site of a
polyhedron, the structure of 8 can be considered as a
trigonal bipyramid, very similar to that of 6. The three
nitrogen atoms of the planar pyridine ligand again
occupy an equatorial and both axial sites with a
CdÃO(4)
CdÃO(2)
2.248(2)
2.272(3)
2.383(3)
2.680(2)
1.286(4)
1.333(4)
1.434(4)
1.240(4)
1.225(4)
1.284(3)
CdÃN(12)
CdÃN(11)
CdÃO(1)
C(11)ÃN(11)
C(21)ÃN(12)
C(26)ÃN(13)
N(1)ÃO(2)
N(1)ÃO(1)
N(2)ÃO(5)
2.257(3)
2.344(3)
2.490(3)
1.436(4)
1.333(4)
1.292(4)
1.238(4)
1.261(4)
1.256(4)
CdÃN(13)
CdÁ Á ÁO(5)
C(19)ÃN(11)
C(25)ÃN(12)
C(28)ÃN(13)
N(1)ÃO(3)
N(2)ÃO(6)
N(2)ÃO(4)
significant distortion in the axial bond angle of
˚
N(py) bond (2.257(3) A) is again
141.17(9)8. The CdÃ
/
significantly shorter than the CdÃ
/
N(imino) bonds
Bond angles
˚
(average 2.36 A).
O(4)ÃCdÃN(12)
N(12)ÃCdÃO(2)
N(12)ÃCdÃN(11)
O(4)ÃCdÃN(13)
O(2)ÃCdÃN(13)
O(4)ÃCdÃO(1)
O(2)ÃCdÃO(1)
N(13)ÃCdÃO(1)
C(11)ÃN(11)Cd
C(25)ÃN(12)ÃCd
C(28)ÃN(13)ÃCd
O(2)ÃN(1)ÃO(1)
O(6)ÃN(2)ÃO(5)
O(5)ÃN(2)ÃO(4)
N(1)ÃO(2)ÃCd
126.57(9)
O(4)ÃCdÃO(2)
86.07(10)
111.82(9)
100.14(10)
70.56(9)
141.17(9)
94.33(9)
85.90(9)
117.3(2)
119.0(2)
116.2(2)
121.7(3)
120.3(4)
119.9(3)
88.9(2)
147.34(10) O(4)ÃCdÃN(11)
70.89(9)
O(2)ÃCdÃN(11)
94.77(10) N(12)ÃCdÃN(13)
109.77(10) N(11)ÃCdÃN(13)
4. Supplementary material
138.49(9)
N(12)ÃCdÃO(1)
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 164862Á164864 for com-
pounds 2, 6 and 8, respectively. Copies of this informa-
tion may be obtained free of charge from The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
53.18(10) N(11)ÃCdÃO(1)
92.52(10) C(19)ÃN(11)ÃCd
120.95(19) C(21)ÃN(12)ÃCd
119.6(2)
121.0(2)
117.8(3)
122.5(3)
117.6(3)
100.0(2)
/
C(26)ÃN(13)ÃCd
O(2)ÃN(1)ÃO(3)
O(3)ÃN(1)ÃO(1)
O(6)ÃN(2)ÃO(4)
N(1)ÃO(1)ÃCd
N(2)ÃO(4)ÃCd
(fax: ꢂ44-1223-336-033; e-mail: deposit@ccdc.cam.a-
c.uk or www: http://www.ccdc.cam.ac.uk).
/
105.42(19)
is only partially soluble in CH2Cl2, CH3Cl, and acetone
supporting its ionic formulation.
Acknowledgements
The reaction of equimolar amounts of pydimMe2 and
Cd(NO3)2 in methanol at 20 8C yields (pydim-
Me2)Cd(NO3)2 (8). This complex is air stable and
moderately soluble in THF, acetone and CH2Cl2.
An ORTEP drawing of (pydimMe2)Cd(NO3)2 (8) is
shown in Fig. 3 and Table 4 shows selected bond angles
The authors thank the National Science Foundation
(CHE-0110493) and the National Institute of Health
(GM-26295) for support. The Bruker CCD Single
Crystal Diffractometer was purchased using funds
provided by the NSF Instrumentation for Materials
Research Program through Grant DMR: 9975623.

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9
(b) D.L. Reger, S.S. Mason, A.L. Rheingold, Inorg. Chim. Acta
240 (1995) 669;
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