M. N. Kopylovich, J. Lasri, M. F. C. Guedes da Silva, A. J. L. Pombeiro
FULL PAPER
1.00 mmol) and 3 (168 mg, 2.00 mmol) were added to the corre-
sponding alcohol ROH (R = Me, Et, nPr or nBu) (5 mL) and the
reaction mixture was refluxed or heated at 100 °C (in the case of
n-butanol) for 12 h (homogenization of the reaction mixture was
observed within ca. 1 h, giving a yellow solution). The solvent was
then removed in vacuo, and the residue washed with three 10 mL
portions of diethyl ether and then dried in air to give [Pd(Htap)2]-
Cl2 (4Ј). Recrystallization of 4Ј from a methanol/chloroform (1:1)
solution, with the addition of nPrNH2 (2.00 equiv. to 4Ј) gave the
yellow palladium(II) complexes [Pd(tap)2] 4a–4d. Compounds 4a–
4d were isolated as mixtures of isomers (see NMR spectroscopic
data) and all attempts to obtain single crystals suitable for XRD
analysis failed.
portions of water (to remove the NaCl), and the remaining residue
was crystallized from an acetone-water (10:1) mixture to give the
corresponding symmetrical palladium(II) complexes 6a–6d, which
were isolated as mixtures of isomers (see NMR spectroscopic data).
All attempts to obtain single crystals suitable for XRD analysis
failed.
[Pd{HN=C(OMe)NC(OMe)=NH}2] (6a): Yield 80% (293 mg)
based on PdCl2. Decomp. temp. Ͼ 250 °C. C8H16N6O4Pd (366):
calcd. C 26.20, H 4.40, N 22.92; found C 26.45, H 4.81, N 23.12.
ESI-MS: m/z (%) = 367 [M + H]+. IR: ν = 3359 (NH), 1613 (C=N)
˜
1
cm–1. H NMR (300 MHz, [D6]DMSO): δ = 3.66–3.75 (m, 12 H,
CH3) ppm. 13C{1H} NMR (400 MHz, [D6]DMSO): δ = 54.9, 55.0,
55.1, 55.6, 55.7 (CH3), 160.9, 161.1, 161.3, 161.6, 162.0 (C=NH)
ppm.
[Pd{HN=C(NH2)NC(OMe)=NH}2] (4a): Yield 75% (252 mg)
based on PdCl2. Decomp. temp. Ͼ 120 °C. C6H14N8O2Pd (336):
calcd. C 21.41, H 4.19, N 33.29; found C 21.76, H 4.27, N 33.36.
[Pd{HN=C(OEt)NC(OEt)=NH}2] (6b): Yield 79% (333 mg) based
on PdCl2. Decomp. temp. Ͼ 230 °C. C12H24N6O4Pd (422): calcd.
C 34.09, H 5.72, N 19.88; found C 34.23, H 5.99, N 20.07. ESI-
ESI-MS: m/z (%) = 337 [M + H]+. IR: ν = 3401 (NH), 1558, 1668
˜
and 1686 (C=N) cm–1. 1H NMR (300 MHz, CD3OD): δ = 3.99,
4.01, 4.04 (3 s, 6 H, CH3) ppm. 13C{1H} NMR (400 MHz,
CD3OD): δ = 55.2, 55.6, 55.9 (CH3), 152.4, 152.7, 154.1, 154.4,
154.6 (C=NH) ppm.
MS: m/z (%) = 423 [M + H]+. IR: ν = 3371 (NH), 1610 (C=N)
˜
1
cm–1. H NMR (300 MHz, [D6]DMSO): δ = 1.19–1.24 (m, 12 H,
CH3), 4.12–4.24 (m, 8 H, CH2) ppm. 13C{1H} NMR (400 MHz,
[D6]DMSO): δ = 15.0, 15.1 (CH3), 64.1, 64.2 (CH2), 160.8, 161.1
(C=NH) ppm.
[Pd{HN=C(NH2)NC(OEt)=NH}2] (4b): Yield 77% (280 mg) based
on PdCl2. Decomp. temp. Ͼ 110 °C. C8H18N8O2Pd (364): calcd. C
26.35, H 4.97, N 30.72; found C 26.66, H 5.13, N 31.05. ESI-MS:
[Pd{HN=C(OPr)NC(OPr)=NH}2] (6c): Yield 81% (387 mg) based
on PdCl2. Decomp. temp. Ͼ 230 °C. C16H32N6O4Pd (478): calcd.
C 40.13, H 6.74, N 17.55; found C 40.34, H 6.88, N 17.69. ESI-
m/z (%) = 365 [M + H]+. IR: ν = 3321 (NH), 1549 and 1689 (C=N)
˜
cm–1. 1H NMR (300 MHz, CD3OD): δ = 1.40–1.46 (m, 6 H, CH3),
4
H, CH2) ppm. 13C{1H} NMR (400 MHz,
MS: m/z (%) = 479 [M + H]+. IR: ν = 3376 (NH), 1608 and 1633
4.28–4.46 (m,
˜
1
(C=N) cm–1. H NMR (300 MHz, [D6]DMSO): δ = 0.87–0.93 (m,
CD3OD): δ = 12.7, 12.8, 12.9, 12.9 (CH3), 65.3, 65.8, 66.1, 66.2
(CH2), 152.4, 152.7, 152.8, 153.4, 153.7, 153.8, 154.2, 154.5
(C=NH) ppm.
12 H, CH3), 1.57–1.65 (m, 8 H, CH3CH2), 4.02–4.18 (m, 8 H,
OCH2) ppm. 13C{1H} NMR (400 MHz, [D6]DMSO): δ = 10.4,
10.6, 10.7 (CH3), 21.9, 22.4, 22.5 (CH3CH2), 69.1, 69.7, 69.8, 70.0
(OCH2), 160.9, 161.3 (C=NH) ppm.
[Pd{HN=C(NH2)NC(OPr)=NH}2] (4c): Yield 73% (286 mg) based
on PdCl2. Decomp. temp. Ͼ 100 °C. C10H22N8O2Pd (392): calcd.
C 30.58, H 5.65, N 28.53; found C 30.67, H 5.95, N 28.77. ESI-
[Pd{HN=C(O(CH2)2OMe)NC(O(CH2)2OMe)=NH}2] (6d): Yield
MS: m/z (%) = 393 [M + H]+. IR: ν = 3328 (NH), 1552 and 1689
˜
83% (450 mg) based on PdCl2. Decomp. temp.
Ͼ 200 °C.
(C=N) cm–1. 1H NMR (300 MHz, CD3OD): δ = 0.91–1.07 (m, 6
H, CH3), 1.51–1.85 (m, 4 H, CH3CH2), 4.19–4.36 (m, 4 H, OCH2)
ppm. 13C{1H} NMR (400 MHz, CD3OD): δ = 8.95, 8.99, 9.02,
9.05, 9.22 (CH3), 21.3, 21.4, 21.5, 25.3 (CH2), 63.3, 70.7, 71.2, 71.4,
71.5, 71.6 (OCH2), 152.4, 152.7, 152.8, 153.3, 153.5, 153.8, 153.9,
154.3, 154.6 (C=NH) ppm.
C16H32N6O8Pd (542): calcd. C 35.40, H 5.94, N 15.48; found C
35.67, H 5.89, N 15.77. ESI-MS: m/z (%) = 543 [M + H]+. IR: ν
˜
= 3331 (NH), 1615 (C=N) cm–1. 1H NMR (300 MHz, [D6]DMSO):
δ = 3.26–3.27 (m, 12 H, CH3), 3.53 (br. s, 8 H, CH3OCH2), 4.21
and 4.27 (2 br. s, 8 H, OCH2) ppm. 13C{1H} NMR (400 MHz, [D6]
DMSO): δ = 58.5 (OCH3), 66.6 (CH3OCH2), 70.7 (OCH2), 160.5
(C=NH) ppm.
[Pd{HN=C(NH2)NC(OBu)=NH}2] (4d): Yield 78% (328 mg) based
on PdCl2. Decomp. temp. Ͼ 100 °C. C12H26N8O2Pd (420): calcd.
C 34.25, H 6.23, N 26.63; found C 34.37, H 6.55, N 26.87. ESI-
X-ray Structure Determination: Single crystals of 2c were obtained
as indicated above. Intensity data were collected on a Bruker AXS-
KAPPA APEX II diffractometer with graphite monochromated
Mo-Kα (λ 0.71073) radiation. Data were collected at 150 K with
omega scans at 0.5° steps and full sphere of data was obtained.
Cell parameters were retrieved with the Bruker SMART software
and refined against all the observed reflections with the Bruker
SAINT[34] program. An absorption correction was applied with
SADABS.[34] The structure was solved by direct methods with the
SHELXS–97 package[35] and refined with SHELXL–97.[36] Calcu-
lations were performed with WinGX software (version 1.80.03).[37]
All hydrogen atoms were inserted into the model at calculated posi-
tions, except for H1 and H2 and the methanol hydrogen atom H10
that were located from the difference Fourier maps. Least square
refinement, with anisotropic thermal parameters for all the non–
hydrogen atoms and isotropic parameters for the hydrogen atoms,
gave R1 = 0.0196 [IϾ2σ(I)] and R1 = 0.0207 (all data). The maxi-
mum and minimum peaks in the final difference electron-density
map are of 0.435 and –0.553 eÅ–3. Crystallographic data are listed
in Table 1.
MS: m/z (%) = 421 [M + H]+. IR: ν = 3428 (NH), 1550 and 1682
˜
(C=N) cm–1. 1H NMR [300 MHz, CDCl3(90%), CD3OD(10%)]: δ
= 0.80–0.88 (m, 6 H, CH3), 1.26–1.35 (m, 4 H, CH3CH2), 1.39–
1.65 (m, 4 H, OCH2CH2), 4.22 (br. s, 4 H, OCH2) ppm. 13C{1H}
NMR [400 MHz, CDCl3(90%), CD3OD(10%)]: δ = 13.2, 13.3,
13.4, 13.5, 13.6 (CH3), 18.5, 18.6, 18.6, 18.7, 19.2 (CH3CH2), 29.8,
30.0, 30.1, 31.7, 34.4 (OCH2CH2), 62.0, 62.1, 65.2, 70.1, 70.3
(OCH2), 152.2, 152.9, 153.8, 154.2 (C=NH) ppm.
Reactions of Sodium Dicyanamide NaN(CϵN)2 (5) with PdCl2 and
Aliphatic Alcohols ROH [R=Me, Et, Pr, (CH2)2OMe] with the For-
mation of Symmetrical (2,4-Dialkoxy-1,3,5-triazapentadienate)pal-
ladium(II) Complexes 6a–6d: PdCl2 (177 mg, 1.00 mmol) and 5
(178 mg, 2.00 mmol) were added to the corresponding alcohol
ROH [R = Me, Et, nPr or (CH2)2OMe] (5 mL) and the reaction
mixture was refluxed or heated at 100 °C (in the case of 2-methoxy-
ethanol) for 12 h (homogenization of the reaction mixture was ob-
served within ca. 1–2 h, giving a yellow solution). The solvent was
then removed in vacuo, and the residue washed with three 10 mL
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Eur. J. Inorg. Chem. 2011, 377–383