Structural organization of nickel(II), zinc(II), and copper(II) complexes with diisobutyldithiocarbamate: EPR, 13C and 15N CP/MAS NMR, and X-ray diffraction studies

Article abstract of DOI:10.1007/s11173-005-0157-4

The structures and spectroscopic properties of nickel(II), zinc(II), and copper(II) complexes with dibutyl- and diisobutyldithiocarbamate were studied by EPR and ¹³C and ¹⁵N CP/MAS NMR spectroscopy and X-ray diffraction analysis. According to the EPR data, copper(II) forms mononuclear [^63/65Cu{S₂CNR₂}₂] and heterobinuclear complexes [^63/65CuZn{S₂CNR ₂}₄] under magnetic dilution conditions. The isomeric forms of nickel(II) and zinc(II) diisobutyldithiocarbamates were detected by ¹³C and ¹⁵N NMR spectroscopy. The crystalline zinc(II) diisobutyldithiocarbamate was found to have a unique structural organization with alternating mononuclear [Zn{S₂CN(i-C₄H ₉)₂}₂] and binuclear molecular forms [Zn ₂{ S₂CN(i-C₄H₉)₂} ₄] in the 1 : 1 ratio.

Full text of DOI:10.1007/s11173-005-0157-4

Russian Journal of Coordination Chemistry, Vol. 31, No. 10, 2005, pp. 695–707. Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 10, 2005, pp. 733–745.
Original Russian Text Copyright © 2005 by Ivanov, Korneeva, Gerasimenko, Forsling.
Structural Organization of Nickel(II), Zinc(II),
and Copper(II) Complexes with Diisobutyldithiocarbamate:
EPR, 13C and 15N CP/MAS NMR,
and X-Ray Diffraction Studies
A. V. Ivanov*, E. V. Korneeva*, A. V. Gerasimenko**, and W. Forsling***
* Amur Institute of Integrated Research, Amur Scientific Center, Far East Division, Russian Academy of Sciences,
Relochnyi per. 1, Blagoveshchensk, 675000 Russia
** Institute of Chemistry, Far East Division, Russian Academy of Sciences,
pr. Stoletiya Vladivostoka 159, Vladivostok, 690022 Russia
*** Luleå University of Technology, S-971 87, Luleå, Sweden
Received November 29, 2004
Abstract—The structures and spectroscopic properties of nickel(II), zinc(II), and copper(II) complexes with
dibutyl- and diisobutyldithiocarbamate were studied by EPR and 13C and 15N CP/MAS NMR spectroscopy and
X-ray diffraction analysis. According to the EPR data, copper(II) forms mononuclear [63/65Cu{S2CNR2}2] and
heterobinuclear complexes [63/65CuZn{S2CNR2}4] under magnetic dilution conditions. The isomeric forms of
nickel(II) and zinc(II) diisobutyldithiocarbamates were detected by 13C and 15N NMR spectroscopy. The crys-
talline zinc(II) diisobutyldithiocarbamate was found to have a unique structural organization with alternating
mononuclear [Zn{S2CN(i-C4H9)2}2] and binuclear molecular forms [Zn2{S2CN(i-C4H9)2}4] in the 1 : 1 ratio.
Dithiocarbamate complexes of transition metals have elongated nonplanar eight-membered chelate ring
found wide use in various areas of practical activity [1]. [Zn2S4C2] in the chair [21–25, 27–31] or tub conforma-
For coordination chemistry, dialkyldithiocarbamates are tion [19, 20, 26]. The coordination polyhedron of the
of interest as ligands with different structural functions zinc atom is a distorted tetrahedron or a trigonal bipyr-
(monodentate, terminal bidentate, bridging bidentate, amid composed of sulfur atoms. The only exception is
and mixed), which allows their complexes to be structur- the mononuclear dicyclohexyldithiocarbamate com-
ally organized in a variety of types (mono-, bi-, tri-, and, plex [Zn{S2CN(c-C6H11)2}2] with a tetrahedral struc-
in the general case, polynuclear).
ture [31]. (The presence of the two bulky cycloalkyl
substituents in the ligand makes it sterically impossible
to form a binuclear molecular structure.)
However, dithiocarbamate complexes containing
ligands with long-chain alkyl substituents have been
poorly studied to date, although they can be of the
greatest practical interest (as molecular precursors of
film metal sulfides) because the molecular volatility in
a vacuum increases with a lengthening of the hydrocar-
bon chain of a substituent.
Mononuclear centrosymmetric nickel(II) com-
plexes with dithiocarbamate ligands [Ni(S2CNR2)2] [2–
18] contain the terminal dithiocarbamate groups coor-
dinated by nickel in a bidentate manner through two
sulfur atoms to give small planar four-membered che-
late rings [NiS2C] (R = CH3 [2], C2H5 [3–5], C3H7 [6,
7], i-C3H7 [8], C4H9 [9, 10], i-C4H9 [9, 11], and C2H5O
[12] or R2 = (CH2)4 [13], (CH2)5 [14], (CH2)6 [7, 15,
16], C6H5 and CH3CO [17], and CH3 and C6H5 [18]). In
contrast to nickel, zinc forms binuclear molecular
structures [Zn2(S2CNR2)4] [19–31] (R = CH3 [19, 20],
C2H5 [21–23], C3H7 [24], i-C3H7 [25], C4H9 [26], and
CH2CH = CH2 [27] or R2 = (CH2)4 [28], (CH2)6 [29],
CH3 and C2H5, CH3 and C3H7, CH3 and i-C3H7, CH3
and C4H9 [30], and C2H5 and cyclo-C6H11 [31]), in
which the dithiocarbamate ligands are structurally non-
equivalent in pairs. Two of them, namely, terminal
The goal of this study was to obtain nickel(II),
zinc(II), and copper(II) complexes with diisobutyl- and
dibutyldithiocarbamate and compare their structural
organizations.
EXPERIMENTAL
Nickel(II) and zinc(II) complexes with dibutyl- (BDtc)
bidentate ligands, form four-membered chelate rings and diisobutyldithiocarbamate (i-BDtc) I–III were
[ZnS2C], while the other two (bridging ligands) connect obtained by reactions of aqueous solutions of NiCl2 ·
the adjacent Zn atoms. The resulting dimer includes an 6H2O and ZnCl2 with the corresponding sodium dithio-
1070-3284/05/3110-0695 © 2005 Pleiades Publishing, Inc.

696
IVANOV et al.
carbamates used in a stoichiometric excess (~10%). analysis, single crystals of complex III were obtained
The resulting voluminous precipitates were washed by from anhydrous ethanol.
decanting, filtered off, and dried in air. The complexes
were additionally purified by recrystallization from
organic solvents.
For Zn3S12N6C54H108, [Zn(BDtc)2][Zn2(BDtc)4]
(M = 1422.42)
anal. calcd.
Found (%):
Zn, 13.79.
Zn, 13.62/13.48 (64Zn/66Zn).
Synthesis of bis(N,N-dibutyldithiocarbamato-
S,S')nickel(II) [Ni{S2CN(C4H9)2}2] (I). A solution of
Na{S2CN(C4H9)2} · H2O (4.91 g, 0.02 mol) in water
(100 ml) was added to a vigorously stirred solution of
NiCl2 · 6H2O (2.38 g, 0.01 mol) in water (100 ml). The
dark green precipitate was washed by decanting, fil-
tered off, and dried in air. Recrystallization from a mix-
ture of anhydrous ethanol and chloroform (1 : 1) gave
long dark-green acicular crystals. The yield of complex I
was 90%.
For EPR studies, isotope-substituted copper(II) com-
plexes were obtained as described for complexes I–III
but in a magnetically diluted state (Cu : M = 1 : 1000)
from isotope-enriched cupric salts with a copper con-
tent of 99.3(1) at % for 63Cu and 99.2(1) at % for 65Cu.
EPR spectra were recorded on a 70-02 XD/1 radio
spectrometer (~9.5 GHz; MP SZ, Minsk) at ~295 K.
The operating frequency was measured with a ChZ-46
microwave frequency meter. g Factors were calculated
with reference to DPPH. The error in the determination
of g factors was 0.002; hyperfine structure (HFS)
constants are given in oersteds (Oe) to within 2%.
EPR spectra were modeled at the MP2 level with the
WIN-EPR SimFonia program (Bruker Co. software,
version 1.2). During the fitting of model spectra to
experimental ones, g factors, HFS constants, resonance
line widths, and contributions (in percent) from the
Lorentz and Gauss components to the line shape were
varied.
For NiS4N2C18H36, [Ni(BDtc)2] (M = 467.45)
anal. calcd. (%): Ni, 12.56.
Found (%):
Ni, 12.11/12.02
(data for the 58Ni/60Ni nuclides).
Synthesis of bis(N,N-diisobutyldithiocarbamato-
S,S')nickel(II) [Ni{S2CN(i-C4H9)2}2] (II). A solution
of Na{S2CN(i-C4H9)2} · 3H2O (5.63 g, 0.02 mol) in
water (100 ml) was added to a vigorously stirred solution
of NiCl2 · 6H2O (2.38 g, 0.01 mol) in water (100 ml). The
light green precipitate was washed by decanting, fil-
tered off, and dried in air. Recrystallization from a mix-
ture of anhydrous ethanol and chloroform (1 : 1) gave
crystals as thin light green plates. The yield of complex II
was 93%.
13C and 15N MAS NMR spectra were recorded on a
CMX-360 pulse spectrometer (Chemagnetics Infinity
Co.) operating at 90.52 and 36.48 MHz, respectively
(superconducting magnet with B0 = 8.46 T; Fourier
transform). The H–13C and H–15N cross polarization
techniques were used. The 13C–1H and 15N–1H dipolar
interactions were suppressed via proton decoupling in a
magnetic field with the corresponding proton resonance
frequency [32]. Samples (~350 mg) of the complexes
were packed into ZrO2 rotors 7.5 mm in diameter. The
spinning rates in 13C/15N MAS NMR experiments were
3400 to 5000/2600 to 3100(1) Hz; the excitation pulse
duration was 4.5 to 5.0/5.0 µs; the pulses were spaced
at 2.0/2.0 to 2.5 s. Because of the relatively low natural
contents of the 13C/15N nuclides (1.108/0.365 at %), the
spectra accumulation technique was used: the number
of scans was 460 to 3000/2200 to 20 600.
1
1
For NiS4N2C18H36, [Ni(i-BDtc) ] (M = 467.45)
2
anal. calcd. (%):
Found (%):
Ni, 12.56.
Ni, 12.42/12.31 (58Ni/60Ni).
Synthesis of zinc diisobutyldithiocarbamate III
composed of binuclear molecules of bis[m-(N,N-
diisobutyldithiocarbamato-S,S,S')(N,N-diisobutyldi-
thiocarbamato-S,S')zinc(II)] [Zn2{S2CN(i-C4H9)2}4]
and mononuclear molecules of bis(N,N-diisobutyl-
dithiocarbamato-S,S')zinc(II) [Zn{S2CN(i-C4H9)2}2].
A solution of Na{S2CN(i-C4H9)2} · 3H2O (5.63 g,
0.02 mol) in water (50 ml) was added to a vigorously
stirred solution of ZnCl2 (1.36 g, 0.01 mol) in water
(100 ml). The reaction mixture was stirred with a mag-
netic stirrer to give a light brown oily product that rap-
Isotropic 13C and 15N chemical shifts δ (ppm) are ref-
erenced to a line of crystalline adamantane used as the
external standard (δ 38.56 ppm relative to tetramethylsi-
lane [33]) and crystalline NH4Cl (δ 0 ppm; –341 ppm on
the absolute scale [34, 35]). The width of a reference
line (2.4 Hz) for crystalline adamantane was used to
idly crystallized in air. The reaction mixture was left check the uniformity of the magnetic field. The δ values
overnight. The resulting white finely crystalline precip- were corrected for drift of the magnetic field strength
itate was filtered off, washed with water, and dried in during the measurements (its frequency equivalent for
air. Both products were spectrally identical. The total 13C/15N nuclei was 0.050/0.017 Hz/h). Chemical shifts
yield of complex III was 79%. For X-ray diffraction and integrated intensity ratios for overlapping signals in
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 10 2005

STRUCTURAL ORGANIZATION OF NICKEL(II), ZINC(II), AND COPPER(II) COMPLEXES
697
Table 1. Selected crystallographic parameters and a summary of data collection and refinement for structure III
Parameter
Value
Empirical formula
M
C54H108N6S12Zn3
Orthorhombic
1422.29
Crystal system
a, b, c, Å
38.220(4), 9.341(1), 21.288(2)
α = β = γ, deg
V, Å3
90°
7600(1)
4
Z
Space group
ρ(calcd), g/cm3
T, K
Pna21
1.243
295(2)
Wave length (MoKα), Å
Crystal size, mm
θ scan range, deg
Ranges of h, k, l indices
0.71073
Prism (0.08 × 0.15 × 0.25)
3.06–23.29
–42 ≤ h ≤ 42, –5 ≤ k ≤ 10, –21 ≤ l ≤ 23
Number of measured reflections
Number of independent reflections
Rint
28977
10284
0.0933
4547
Number of reflections with I > 2σ(I)
Refinement method
full-matrix least squares on F2
700
Number of parameters refined
R factors for F2 > 2σ(F2)
R factors for all reflections
GOOF
R1 = 0.0408, wR2 = 0.0516
R1 = 0.1160, wR2 = 0.0609
0.649
Residual electron density (min/max), e/Å3
–0.248/0.348
the 13C NMR spectra were additionally refined by frag- 345 frames for ϕ = 0°, 90°, and 180°, respectively; ω
ment-by-fragment mathematical modeling with con-
sideration of the line positions and widths and the con-
tributions from the Lorentz and Gauss components to
the line shapes.
scanning was carried out at a scan step of 0.2° and a
frame exposure time of 10 s. Absorption correction was
applied from equivalent reflections. The structure was
solved by the direct method and refined by the least-
squares method in isotropic approximation for the
C(17) and C(18) atoms and in anisotropic approxima-
tion for the rest of non-hydrogen atoms. The hydrogen
atoms were located geometrically and refined in the
X-ray diffraction analysis of complex III was per-
formed on a SMART 1000 CCD diffractometer (MoKα
radiation, graphite monochromator; crystal–detector
distance 45 mm) with an edged single crystal. Reflec-
tions were collected in sets composed of 906, 660, and rider model, except for the HC(17) and HC(18) protons
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 10 2005

698
IVANOV et al.
Table 2. Coordinates and isotropic equivalent thermal parameters Uequiv of the non-hydrogen atoms for structure III
Atom
x
y
z
Uequiv, Å2 Atom
x
y
z
Uequiv, Å2
Zn(1) 0.83641(1) 0.86993(6) 0.59880(2) 0.0617(2) C(18) 0.9914(1) 1.1330(6) 0.5488(2)
Zn(2) 0.91623(1) 0.69746(6) 0.64503(2) 0.0617(2) C(19) 0.8520(1) 0.5310(4) 0.6094(2)
Zn(3) 0.62494(2) 0.29711(7) 0.62096(3) 0.0722(2) C(20) 0.8169(1) 0.3314(4) 0.6462(2)
0.139(3)
0.053(2)
0.066(2)
0.071(2)
0.107(2)
0.110(2)
0.067(2)
0.077(2)
0.126(3)
0.098(2)
0.057(2)
0.074(2)
0.200(4)
0.179(3)
0.142(3)
0.076(2)
0.231(4)
0.190(4)
0.229(4)
0.058(2)
0.066(2)
0.086(2)
0.128(2)
0.126(2)
0.068(2)
0.081(2)
0.103(2)
0.131(2)
0.052(2)
0.064(2)
0.077(2)
0.111(2)
0.125(3)
0.074(2)
0.094(2)
0.117(3)
0.143(3)
S(1)
S(2)
S(3)
S(4)
S(5)
S(6)
S(7)
S(8)
S(9)
0.79186(3) 0.8245(2) 0.67148(5) 0.0699(5) C(21) 0.7972(1) 0.3796(5) 0.7055(2)
0.78173(3) 0.9109(2) 0.53999(6) 0.0735(5) C(22) 0.7979(1) 0.2570(5) 0.7529(2)
0.87367(3) 0.10558(1) 0.57079(5) 0.0668(5) C(23) 0.7595(1) 0.4255(5) 0.6920(2)
0.89083(3) 0.9070(1) 0.68967(5) 0.0626(4) C(24) 0.8003(1) 0.4576(5) 0.5475(2)
0.87846(3) 0.5126(1) 0.67336(5) 0.0654(5) C(25) 0.8048(1) 0.3378(5) 0.4982(2)
0.86301(3) 0.6626(1) 0.55453(5) 0.0603(4) C(26) 0.7732(1) 0.3405(6) 0.4555(2)
0.96981(3) 0.6450(1) 0.70487(6) 0.0733(5) C(27) 0.8382(1) 0.3491(5) 0.4611(2)
0.96202(3) 0.7359(2) 0.57409(5) 0.0737(5) C(28) 0.9889(1) 0.7002(5) 0.6362(2)
0.65108(3) 0.4230(1) 0.70371(5) 0.0711(5) C(29) 1.0469(1) 0.6813(5) 0.6860(2)
S(10) 0.60253(3) 0.1794(1) 0.70978(6) 0.0778(5) C(30) 1.0596(2) 0.8059(7) 0.7203(3)
S(11) 0.59362(3) 0.3951(1) 0.53712(5) 0.0705(5) C(31) 1.0818(2) 0.7612(7) 0.7724(3)
S(12) 0.65260(3) 0.1933(2) 0.53413(6) 0.0762(5) C(32) 1.0471(1) 0.9387(6) 0.7176(3)
N(1)
N(2)
N(3)
N(4)
N(5)
N(6)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
0.7299(1) 0.8287(3) 0.6151(1)
0.9280(1) 0.11262(3) 0.6410(2)
0.8243(1) 0.4443(3) 0.6012(2)
1.0239(1) 0.7112(4) 0.6329(2)
0.6303(1) 0.3030(4) 0.8113(1)
0.6196(1) 0.2864(4) 0.4310(2)
0.7635(1) 0.8525(4) 0.6092(2)
0.7133(1) 0.7880(5) 0.6743(2)
0.6913(1) 0.9085(5) 0.7047(2)
0.7071(1) 1.0462(5) 0.7054(3)
0.6791(1) 0.8573(6) 0.7683(2)
0.7059(1) 0.8611(5) 0.5605(2)
0.7018(2) 0.7219(7) 0.5173(3)
0.6924(2) 0.5912(6) 0.5402(3)
0.6842(2) 0.7724(7) 0.4563(3)
0.053(1)
0.056(1)
0.051(1)
0.062(1)
0.059(1)
0.054(1)
0.055(2)
0.068(2)
0.098(2)
0.138(3)
0.135(3)
0.070(2)
0.164(3)
0.150(3)
0.182(3)
0.050(2)
0.072(2)
0.082(2)
0.105(2)
0.130(2)
0.063(2)
0.082(2)
0.133(3)
C(33) 1.0413(1) 0.7546(5) 0.5707(2)
C(34) 1.0565(2) 0.6361(6) 0.5354(3)
C(35) 1.0540(2) 0.5055(6) 0.5402(3)
C(36) 1.0699(2) 0.7052(7) 0.4727(3)
C(37) 0.6283(1) 0.3026(5) 0.7478(2)
C(38) 0.6103(1) 0.1985(5) 0.8484(2)
C(39) 0.5732(1) 0.2488(5) 0.8622(2)
C(40) 0.5537(1) 0.1266(6) 0.8938(2)
C(41) 0.5715(1) 0.3849(6) 0.9026(2)
C(42) 0.6536(1) 0.4002(5) 0.8423(2)
C(43) 0.6922(1) 0.3584(5) 0.8437(2)
C(44) 0.6983(1) 0.2217(5) 0.8775(2)
C(45) 0.7148(1) 0.4834(6) 0.8678(2)
C(46) 0.6220(1) 0.2922(5) 0.4952(2)
C(47) 0.5919(1) 0.3618(5) 0.3973(2)
C(48) 0.5567(1) 0.2828(5) 0.3971(2)
C(49) 0.5297(1) 0.3772(6) 0.3648(2)
C(50) 0.5592(2) 0.1357(6) 0.3646(2)
C(51) 0.6441(1) 0.2013(5) 0.3935(2)
C(52) 0.6782(1) 0.2799(6) 0.3776(2)
C(53) 0.6753(1) 0.4223(6) 0.3485(2)
C(54) 0.7020(2) 0.1793(7) 0.3431(2)
C(10) 0.9009(1) 1.0388(4) 0.6348(2)
C(11) 0.9520(1) 1.1196(5) 0.6944(2)
C(12) 0.9471(1) 1.2429(5) 0.7414(2)
C(13) 0.9138(1) 1.2262(5) 0.7786(2)
C(14) 0.9799(1) 1.2555(6) 0.7836(2)
C(15) 0.9355(1) 1.2371(4) 0.5923(2)
C(16) 0.9548(1) 1.1830(5) 0.5362(2)
C(17) 0.9532(1) 1.3032(5) 0.4855(2)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 10 2005

STRUCTURAL ORGANIZATION OF NICKEL(II), ZINC(II), AND COPPER(II) COMPLEXES
699
Table 3. Bond lengths d and angles ω in structure III*
Bond
d, Å
Binuclear molecule
Bridging ligands Terminal ligands
Zn(1)–S(3)
Bond
d, Å
Angle
Bridging ligands
S(3)Zn(1)S(4) 68.75(4) S(1)Zn(1)S(2)
ω, deg
Angle
Terminal ligands
75.35(4)
ω, deg
2.323(1) Zn(1)–S(1)
2.862(1) Zn(1)–S(2)
2.382(1) Zn(2)–S(7)
2.382(1) Zn(2)–S(8)
2.330(1) S(1)–C(1)
2.821(1) S(2)–C(1)
1.721(4) S(7)–C(28)
1.740(4) S(8)–C(28)
1.704(4) N(1)–C(1)
1.747(4) N(1)–C(2)
1.327(4) N(1)–C(6)
1.462(5) N(4)–C(28)
1.493(5) N(4)–C(29)
1.345(4) N(4)–C(33)
1.452(5)
2.340(1)
2.466(1)
2.461(1)
2.339(1)
1.734(4)
1.718(4)
1.713(4)
1.709(4)
1.309(4)
1.461(5)
1.497(5)
1.340(5)
1.457(5)
1.539(5)
S(3)Zn(1)S(6)
S(4)Zn(1)S(6)
S(4)Zn(2)S(6)
S(5)Zn(2)S(4)
S(5)Zn(2)S(6)
C(10)S(3)Zn(1)
C(19)S(6)Zn(1)
C(10)S(4)Zn(2)
C(19)S(5)Zn(2)
C(19)S(6)Zn(2)
Zn(1)S(6)Zn(2)
104.15(5) S(8)Zn(2)S(7)
93.18(4) C(1)S(1)Zn(1)
94.22(4) C(1)S(2)Zn(1)
104.65(5) C(28)S(7)Zn(2)
69.17(4) C(28)S(8)Zn(2)
75.06(4)
85.5(1)
Zn(1)–S(4)
Zn(1)–S(6)
Zn(2)–S(4)
Zn(2)–S(5)
Zn(2)–S(6)
S(3)–C(10)
S(4)–C(10)
S(5)–C(19)
S(6)–C(19)
N(2)–C(10)
N(2)–C(11)
N(2)–C(15)
N(3)–C(19)
N(3)–C(20)
N(3)–C(24)
82.0(1)
81.6(2)
85.5(2)
95.6(1)
101.8(1)
102.9(1)
94.9(2)
C(1)N(1)C(2)
C(1)N(1)C(6)
C(2)N(1)C(6)
123.6(3)
120.1(3)
116.2(3)
C(28)N(4)C(29) 123.0(4)
C(28)N(4)C(33) 119.8(4)
78.3(1)
86.77(4) C(29)N(4)C(33) 117.1(3)
C(10)N(2)C(11) 122.8(3)
C(10)N(2)C(15) 120.5(3)
C(11)N(2)C(15) 116.7(3)
C(19)N(3)C(20) 120.3(3)
C(19)N(3)C(24) 122.8(3)
C(20)N(3)C(24) 116.9(3)
N(1)C(1)S(1)
N(1)C(1)S(2)
N(4)C(28)S(7)
N(4)C(28)S(8)
S(2)C(1)S(1)
S(8)C(28)S(7)
120.9(3)
122.4(3)
119.5(3)
122.9(3)
116.7(2)
117.5(2)
1.470(5)
Mononuclear molecule
2.342(1) S(12)–C(46)
2.349(1) N(5)–C(37)
2.336(1) N(5)–C(38)
2.340(1) N(5)–C(42)
1.703(4) N(6)–C(46)
1.719(4) N(6)–C(47)
1.702(4) N(6)–C(51)
Zn(3)–S(9)
Zn(3)–S(10)
Zn(3)–S(11)
Zn(3)–S(12)
S(9)–C(37)
S(10)–C(37)
S(11)–C(46)
1.706(4)
1.352(5)
1.471(5)
1.433(5)
1.370(5)
1.461(5)
1.465(5)
N(2)C(10)S(3)
N(2)C(10)S(4)
N(3)C(19)S(5)
N(3)C(19)S(6)
S(3)C(10)S(4)
S(5)C(19)S(6)
119.6(3)
122.7(3)
120.7(3)
121.7(3)
117.6(2)
117.5(2)
Mononuclear molecule
Angle
ω, deg
Binuclear molecule
S(1)Zn(1)S(3) 138.71(5) S(4)Zn(2)S(7)
S(1)Zn(1)S(4) 95.96(4) S(4)Zn(2)S(8)
Angle
ω, deg
S(9)Zn(3)S(10)
S(11)Zn(3)S(9)
77.59(5) C(37)N(5)C(42) 119.8(3)
126.63(5) C(42)N(5)C(38) 119.8(3)
107.22(5) S(11)Zn(3)S(10) 127.71(5) C(46)N(6)C(47) 121.2(3)
115.87(5) S(11)Zn(3)S(12)
103.53(5) S(12)Zn(3)S(9)
77.89(5) C(46)N(6)C(51) 121.4(4)
127.56(5) C(47)N(6)C(51) 117.3(3)
S(1)Zn(1)S(6) 115.14(5) S(5)Zn(2)S(7)
S(2)Zn(1)S(3) 105.87(5) S(5)Zn(2)S(8)
S(2)Zn(1)S(4) 160.15(5) S(6)Zn(2)S(7)
S(2)Zn(1)S(6) 106.67(5) S(6)Zn(2)S(8)
138.11(5) S(12)Zn(3)S(10) 127.35(5) N(5)C(37)S(9)
121.3(3)
158.54(5) C(37)S(9)Zn(3)
96.69(4) C(37)S(10)Zn(3)
C(46)S(11)Zn(3)
82.3(2)
81.8(2)
81.6(2)
81.4(2)
N(5)C(37)S(10) 120.3(3)
N(6)C(46)S(11) 120.2(3)
N(6)C(46)S(12) 120.6(3)
S(9)C(37)S(10) 118.4(2)
S(11)C(46)S(12) 119.2(2)
C(46)S(12)Zn(3)
C(37)N(5)C(38) 120.4(3)
* The symmetry operation code is –x + 1, y, –z + 1/2.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 10 2005

700
IVANOV et al.
DPPH
DPPH
57 Oe
52 Oe
‡
b
H
H
‡'
b'
63
Fig. 1. (a, b) Experimental and (a', b') simulated EPR spectra of the polycrystalline complexes (a, a') [ Cu{S CN(C H ) } ] and
2
4 9 2 2
63
(b, b') [ Cu{S CN(i-C H ) } ] magnetically diluted with nickel(II).
2
4 9 2 2
show a well-resolved HFS due to 63Cu or 65Cu (I = 3/2)
nuclei (I = 3/2) in all the three orientations and an addi-
tional high-field peak of a high intensity [39, 40] (Fig. 1).
The spectral shape and the totality of the EPR parame-
ters suggest that the nickel(II) complexes contain
square-planar chromophores [CuS4] (sp2d-hybridiza-
not detected from the electron-density difference map.
The absolute molecular configurations were deter-
mined with the use of the Flack parameter (0.06(1))
[36]. The collected data were edited and the unit cell
parameters were refined with the SMART and SAINT
Plus programs [37]. All calculations for structure deter-
mination and refinement were performed with the
SHELXTL/PC programs [38]. Selected crystallo-
graphic parameters and a summary of data collection
are given in Table 1. Atomic coordinates are listed in
Table 2. Bond lengths and angles are given in Table 3.
tion state of copper(II): s- + px- + py- + dx
AOs).
2 – y2
From this viewpoint, the observed anisotropy of the
EPR parameters in the xy plane suggests some rhombic
distortion of the planar square because of diagonal non-
equivalence of the M–S bonds.
Thus, copper(II) in the lattices of the corresponding
nickel(II) complexes forms mononuclear dithiocar-
RESULTS AND DISCUSSION
The EPR spectra of copper(II) dibutyl- and bamate complexes [Cu(Dtc)2], although individual cop-
diisobutyldithiocarbamates magnetically diluted with per(II) dithiocarbamates are usually binuclear [41–43]
nickel(II) are nearly axially symmetric (Fig. 1; Table 4). or polynuclear [44]. (Mononuclear copper(II) dithio-
However, computer modeling revealed some aniso- carbamates can be obtained in the individual state only
tropy of the g and A tensors in the xy plane. The spectra when dithiocarbamate ligands contain bulky alkyl sub-
Table 4. EPR parameters of magnetically diluted copper(II) dithiocarbamates
AC1 u*
AC2 u*
AC3 u*
g2
g3
Complex
g1
[Cu/Ni{S2CN(C4H9)2}2]
[Cu/Ni{S2CN(i-C4H9)2}2]
[CuZn{S2CN(C4H9)2}4]
[Cu/Zn{S2CN(i-C4H9)2}2]
[CuZn{S2CN(i-C4H9)2}4]
2.086
2.086
2.109
2.087
2.107
159/170
161/172
136/146
157/168
140/150
2.023
2.024
2.039
2.026
2.032
41/44
41/44
33/35
44/47
27/29
2.020
2.019
2.027
2.019
2.030
38/41
38/41
18/19
29/31
18/19
63
65
* The HFS constants are given for the Cu/ Cu nuclei.
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STRUCTURAL ORGANIZATION OF NICKEL(II), ZINC(II), AND COPPER(II) COMPLEXES
DPPH DPPH
701
72 Oe
72 Oe
H
H
‡
b
‡'
b'
63
Fig. 2. (a, b) Experimental and (a', b') simulated EPR spectra of the complexes (a, a') [ CuZn{S CN(C H ) } ] and
2
4 9 2 4
63
(b, b') [ CuZn{S CN(i-C H ) } ] magnetically diluted with zinc.
2
4 9 2 4
DPPH
57 Oe
H
A1||
A2||
Fig. 3. The EPR spectrum of bis(diisobutyldithiocarbamato)copper(II) magnetically diluted with zinc and freshly precipitated
from water.
stituents [18].) In our case, the formation and stabiliza- tated from an aqueous phase contain a set of low-inten-
tion of the mononuclear complexes [Cu(Dtc)2] is due to
the 1000-fold dilution of the paramagnetic component
with nickel(II) (Cu : Ni = 1 : 1000), under which the
formation of complexes of any other structural types is
a fortiori impossible for copper.
sity signals (Fig. 3) suggesting the presence of cop-
per(II) in two magnetically nonequivalent positions.
The EPR parameters were refined by computer simula-
tion (Fig. 2; Table 4). In the former case, the pro-
nounced triaxial anisotropy of the EPR parameters
reflects the nonplanar structure of the copper(II) poly-
hedron as the result of the formation of heterobinuclear
complexes [CuZn(Dtc)4] in magnetically diluted sys-
tems. According to [45–52], such dimers are formed in
The EPR spectra of crystalline copper(II) dibutyl-
and diisobutyldithiocarbamates magnetically diluted
with zinc and precipitated from organic solvents show
triaxial anisotropy of the EPR parameters (Fig. 2;
Table 4). In addition, the spectra of samples precipi- the reaction of a paramagnetic component with a dia-
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 10 2005

702
IVANOV et al.
(a)
(b)
(c)
210
200
δ, ppm
70
60
50
40
30
20
10
13
Fig. 4. The C CP/MAS NMR spectra (295 K) of the polycrystalline nickel [Ni(S CNR ) ] (R = (a) C H and (b) i-C H ) and
2
2 2
4
9
4 9
(c) zinc complexes [Zn{S CN(i-C H ) } ][Zn {S CN(i-C H ) } ]; the number of scans/spinning rate (Hz) is (a) 460/3700,
2
4
9 2 2
2
2
4 9 2 4
(b) 1504/3400, and (c) 3000/5000.
magnetic matrix. In this case, the geometry of the near- nance signals (Figs. 4a, 5a; Table 5) because of the cen-
est environment [S5] of the complexing metal is inter- trosymmetric character of the molecular structure
mediate between a tetragonal pyramid and a trigonal [Ni{S2CN(C4H9)2}2] [10]. On the contrary, the respective
bipyramid. The EPR parameters of the second paramag- signals in the 13C and 15N NMR spectra of complex II are
netic center correspond to axial symmetry (Table 4) and 1 : 1 doublets, which is due to the structural nonequiva-
are numerically close to those for mononuclear cop- lence of the =NC(S)S– groups in [Ni{S2CN(i-C4H9)2}2]
per(II) dithiocarbamates in the nickel(II) lattice. The (Figs. 4b, 5b). According to the X-ray diffraction data,
slight increase in the g factors and the simultaneous the unit cell of complex II includes two types of struc-
decrease in the HFS constants can be explained by turally nonequivalent centrosymmetric molecules
some distortion of the chromophore [CuS4].
[Ni{S2CN(i-C4H9)2}2] [11] and the ligand nonequiva-
lence is of the intermolecular character.
Thus, in the magnetically diluted complexes
studied, copper(II) forms both mononuclear [Cu(Dtc)2]
and particularly heterobinuclear [CuZn(Dtc)4] mole-
cules (Table 4), as is evident from the substantially
higher intensity of the former set of resonance sig-
nals.
The experimental 13C and 15N CP/MAS NMR intensity ratio 2 : 1 : 1 : 1 : 1 is most informative, which
spectra of complexes I–III suggest their individualities suggests the presence of six nonequivalent dithiocar-
(Figs. 4, 5). In the 13C and 15N NMR spectra of com- bamate groups in that complex. For this reason, the
plex I, the =NC(S)S– groups appear as single reso- character of the 15N NMR spectrum (Fig. 5c) showing
Among the zinc complexes studied by us in [26],
zinc diisobutyldithiocarbamate is characterized by an
13
unusual C NMR spectrum (Fig. 4c) containing reso-
nance signals for the =NC(S)S–, =NCH2–, =CH–, and
−CH3 groups (Table 5). The first set of signals with the
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 10 2005

STRUCTURAL ORGANIZATION OF NICKEL(II), ZINC(II), AND COPPER(II) COMPLEXES
703
(a)
(b)
(c)
150
140
130
120
δ, ppm
15
Fig. 5. The N CP/MAS NMR spectra (295 K) of the polycrystalline nickel [Ni(S CNR ) ] (R = (a) C H and (b) i-C H ) and
2
2 2
4
9
4 9
(c) zinc complexes [Zn{S CN(i-C H ) } ][Zn {S CN(i-C H ) } ]; the number of scans/spinning rate (Hz) is (a) 2200/2600,
2
4
9 2 2
2
2
4 9 2 4
(b) 2500/3100, and (c) 20 600/3000.
six resonance signals (1 : 1 : 1 : 1 : 1 : 1) is quite [Ni{S2CN(i-C4H9)2}2] including only terminal ligands
expected. It is worth noting that recording of 15N NMR (Table 5). Thus, according to the NMR data, the mono-
nuclear and binuclear forms of complex III coexist in
spectra of melted complex III (tending to be over-
cooled) during slow crystallization revealed different
accumulation rates of two terminal doublets with
respect to the intermediate doublet.
the 1 : 1 ratio.
To verify the correctness of our structural conclu-
sions, the structure of complex III was determined
from X-ray diffraction data.
The latter fact is direct evidence of molecular enti-
ties of two types of structure in the complex under con-
sideration. Hence, its 13ë and 15N NMR spectra can
be interpreted as a combination of the binuclear and
mononuclear forms with six structurally nonequiva-
lent ligands. The terminal doublets in the 15N NMR
spectrum were assigned to the binuclear form because
an analogous spectral nonequivalence of the terminal
and bridging ligands was observed in [26] for
[Zn2{S2CN(i-C4H9)2}4] (Table 5). The assignment of
the intermediate doublet in the 15N NMR spectrum of
Description of the molecular structures of
[Zn{S2CN(i-C4H9)2}2] and [Zn2{S2CN(i-C4H9)2}4].
The structural organization of zinc diisobutyldithiocar-
bamate is determined by the coexistence of its mononu-
clear [Zn{S2CN(i-C4H9)2}2] and binuclear forms
[Zn2{S2CN(i-C4H9)2}4] (Fig. 6; Table 3). In the unit cell
of complex III, four structurally equivalent mononu-
clear molecules alternate with four binuclear ones
(Fig. 7). In [Zn{S2CN(i-C4H9)2}2], zinc coordinates
two Dtc ligands in a bidentate manner to form planar
zinc diisobutyldithiocarbamate to the mononuclear four-membered chelate rings [ZnS2C]. The coordina-
form was confirmed by 15N NMR data for the complex tion polyhedron of the zinc atom is a distorted tetrahe-
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 10 2005

704
IVANOV et al.
Table 5. Isotropic 13C and 15N chemical shifts δ (ppm) for nickel(II) and zinc(II) complexes with reference to TMS (13C)
and NH4Cl (15N)
13C
15N
=N–
135.2
Complex
–S(S)CN=
=N–CH2–
–CH2–
–CH=
–CH3
[Ni{S2CN(C4H9)2}2]
205.6
208.3
51.2
55.2
31.4, 21.6, 20.3
15.3
15.6, 14.9, 14.5
(2 : 1 : 1)
Na{S2CN(C4H9)2} · H2O
30.0
21.0
[Zn2{S2CN(i-C4H9)2}4]
204.3, 203.7,
66.4, 66.2,
28.3, 28.0
27.9, 27.8
24.0, 23.5
145.2, 143.5,
125.8, 124.1
(1 : 1 : 1 : 1)
201.9 (34)*, 201.6 65.4, 64.8
22.8, 22.7
(1 : 1 : 1 : 1)
(1 : 1 : 1 : 1)
22.2, 22.1
22.0, 21.5
[Zn{S2CN(i-C4H9)2}2]
[Ni{S2CN(i-C4H9)2}2]
205.8 (40)*
62.3, 60.7
(1 : 3)
27.5, 26.8
21.3, 21.0
133.4, 132.6
(1 : 1)
20.8, 20.0
208.1, 207.5
(1 : 1)
57.6, 56.7
(1 : 1)
28.6, 27.6
(1 : 1)
22.2, 21.4
131.1, 130.3
(1 : 1)
21.0, 20.2
19.7, 19.5
(2 : 1 : 2 : 1 : 1 : 1)
Na{S2CN(i-C4H9)2} · 3H2O
208.2
66.7
28.0, 27.1 23.0, 22.4, 20.8
(1 : 1) (1 : 1 : 2)
13 14
* The asymmetric C– N doublets (Hz).
dron made up of four S atoms. The angle between the atoms and the more distant S(6) and S(4) atoms are
chelate ring planes is nearly right (89.36°). The binu-
clear molecule is formed when adjacent Zn atoms are
connected by two bridging ligands. Two other (termi-
nal) ligands in the dimer form the same four-mem-
bered chelate rings as in the monomer molecule. As
expected from the 13C and 15N NMR data, the Dtc
ligands in both molecules are structurally nonequiva-
lent. In all cases, the coordination is anisobidentate
since one Zn–S bond is noticeably shorter than the
other (although, on the whole, the bridging ligands are
bound to zinc more strongly than are the terminal
ligands (Table 3)).
2.821 and 2.862 Å, respectively. Insofar as these values
are lower than the sum of the van der Waals radii of the
Zn and S atoms [53], there exists a fifth, relatively weak
Zn–S bond (C.N.(Zn) 5). The coordination polyhedra
of zinc are intermediate between a tetragonal pyramid
(TP) and a trigonal bipyramid (TBP). For quantitative
characterization of the polyhedral geometry in metal
complexes with C.N. 5, the parameter τ = (α – β)/60
was proposed in [54]; in our case, α and β are the values
of the two largest SZnS angles (α > β). For an idealized
TP (C4v) τ is zero since α = β. In a regular TBP (C3v),
the axial SZnS angle (α) equals 180°, while the equato-
rial β = 120°; i.e., τ = 1. Any distorted polyhedra are
described by 0 < τ < 1. For the Zn(1) and Zn(2) atoms,
τ = 0.357 and 0.341, respectively. Thus, the contribu-
tion from the TBP to the polyhedral geometry is some-
what more appreciable for Zn(1) than for Zn(2): in
these cases, the ratios of the contributions of TBP (TP)
In all ligands, the C2NC(S)S groups are virtually
planar, which suggests a substantial contribution from
the double bond to the formally single N–C(S)S bond.
In the binuclear molecule, the Zn atoms are sur-
rounded by four relatively strongly bound S atoms
(2.323–2.466 Å) forming, to a first approximation, a
distorted tetrahedron. The distances between the Zn are 35.7 (64.3) and 34.1 (65.9%), respectively.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 10 2005

STRUCTURAL ORGANIZATION OF NICKEL(II), ZINC(II), AND COPPER(II) COMPLEXES
705
(‡)
C(4)
C(6)
C(9)
C(17)
C(16)
C(3)
C(15)
S(2)
N(1)
S(3)
C(7)
C(2)
C(1)
N(2)
Zn(1)
C(5)
C(12)
C(8)
C(18)
C(10)
C(13)
S(1)
C(11)
S(6)
C(14)
C(33)
S(4)
C(24)
C(27)
C(26)
S(8)
C(25)
C(19)
S(5)
C(36)
N(3)
C(20)
C(23)
C(21)
Zn(2)
N(4)
C(28)
C(32)
C(30)
C(34)
S(7)
C(35)
C(22)
C(29)
C(31)
C(53)
C(45)
(b)
C(43)
C(44)
C(54)
C(52)
S(9)
S(12)
S(11)
C(42)
C(51)
C(46)
N(6)
N(5)
Zn(3)
C(47)
C(37)
C(38)
S(10)
C(49)
C(48)
C(50)
C(41)
C(39)
C(40)
Fig. 6. Molecular structures of (a) the binuclear and (b) mononuclear forms of the complex [Zn{S CN(i-C H ) } ][Zn {S CN(i-C H ) } ].
2
4
9 2 2
2
2
4 9 2 4
In the distorted TBPs, the three most strongly bound longer than the Zn–S bonds only by ~15%. In turn, the
S atoms lie in the equatorial plane, while the more dis-
tant S atoms are in the axial positions. The SZnS bond
angles in the equatorial planes of the TBP (Zn(1):
138.71°, 115.14°, and 104.15°; Zn(2): 138.11°,
115.87°, and 104.65°) differ noticeably from 120°; the
axial SaxZnSax angles are 160.14° for Zn(1) and 158.54°
for Zn(2). To a first approximation, the binuclear mole-
cule is centrosymmetric; the Zn–Zn distance is
3.5876(7) Å.
distance between the opposite S atoms is 2.926 to
2.939 Å, thus forming the longer axis of the rhombus.
The configuration of the four-membered chelate ring
allows the trans-annular effect to appear. In contrast,
the geometry of the elongated eight-membered chelate
ring [Zn2S4C2], which is nonplanar as most dithiocar-
bamate complexes, can be approximately described by
the chair conformation.
A comparison of the data obtained for nickel(II) and
zinc(II) dibutyl- and diisobutyldithiocarbamates makes
In the molecules of both structural types, the four-
membered chelate rings [ZnS2C] are characterized by
short Zn–C distances (2.681–2.802 Å), which are it possible to conclude that branched alkyl substituents
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 31 No. 10 2005

706
IVANOV et al.
y
0
x
z
Fig. 7. Crystal structure of [Zn{S CN(i-C H ) } ][Zn {S CN(i-C H ) } ] (projection onto the xz plane).
2
4
9 2 2
2
2
4 9 2 4
5. Selvaraju, R., Panchanatheswaran, K., Thiruvalluvar, A.,
and Parthasarathi, V., Acta Crystallogr., Sect. C: Cryst.
Struct. Commun., 1995, vol. 51, no. 4, p. 606.
at the N atom favor isomerism in coordination com-
pounds.
6. Peyronel, G. and Pignedoli, A., Acta Crystallogr., 1967,
ACKNOWLEDGMENTS
vol. 23, no. 3, p. 398.
7. Ivanov, A.V., Ivakhnenko, E.V., Forshling, V., et al., Zh.
Neorg. Khim., 2002, vol. 47, no. 3, p. 468 [Russ. J. Inorg.
Chem. (Engl. Transl.), vol. 47, no. 3, p. 410].
8. Newman, P.W.G. and White, A.H., J. Chem. Soc., Dalton
Trans., 1972, no. 20, p. 2239.
The authors are grateful to the research engineer
M. Ranheimer for her permanent assistance, to
O.N. Antsutkin for his assistance in some NMR exper-
iments, to I.V. Rodyushkin for his assistance in elemental
analysis, and to the Bruker Co. for free access to the
WIN-EPR SimFonia program. A.V. Ivanov acknowl-
edges the financial support of theAgricola Research Cen-
ter at the Luleå University of Technology (Sweden).
This study was supported by the Ministry of Educa-
tion and Science of the Russian Federation, grant
no. E02-5.0-150 for fundamental research into natural
and exact sciences (2003–2004).
9. Cox, M.J. and Tiekink, E.R.T., Z. Kristallogr., 1999,
vol. 214, no. 4, p. 242.
10. Lokaj, J., Vrabel, V., and Kello, E., Chem. Zvesti, 1984,
vol. 38, p. 313.
11. Raston, C.L. and White, A.H., Aust. J. Chem., 1976,
vol. 29, no. 3, p. 523.
12. Ramalingam, K., Radha A., Aravamudan G., et al., Acta
Crystallogr., Sect. C: Cryst. Struct. Commun., 1984,
vol. 40, no. 11, p. 1838.
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