Synthesis, IR, and multinuclear NMR spectroscopic studies of complexes of the type cis- and trans-Pt(amine)2(NO3)2

Article abstract of DOI:10.1139/v04-012

Compounds of the types cis- and trans-Pt(amine)₂NO ₃)₂ have been synthesized and characterized by IR and multinuclear (¹⁹⁵Pt, ¹³C, and ¹H) NMR spectroscopies. The nitrato IR bands were compared for the two isomers. The ¹⁹⁵Pt NMR resonances of the trans complexes were observed at lower fields (avg. -1570 ppm for primary amines) than the cis analogues (avg. -1698 ppm) for an average Δδ value of 124 ppm. The complexes containing a secondary amine were observed at about the same field for the cis isomers (avg. -1682 ppm) and surprisingly at much higher fields for the trans compounds (avg. -1638 ppm). In ¹H NMR, the coupling constants ²J( ¹⁹⁵Pt-¹HN) are larger for the cis isomers (avg. 67 Hz) than for the trans compounds (avg. 58 Hz). The ³J( ¹⁹⁵Pt-¹H) are also larger for the cis complexes (avg. 40 vs. 33 Hz). In ¹³C NMR, the coupling constants are also geometry dependent. The V(¹⁹⁵Pt-¹³C) are larger for the cis isomers (avg. 37 Hz) than for the trans compounds (avg. 28 Hz). The ²J( ¹⁹⁵Pt-¹³C) are much smaller (avg. 18 Hz for the cis complexes and 16 Hz for the trans isomers).

Full text of DOI:10.1139/v04-012

524
Synthesis, IR, and multinuclear NMR
spectroscopic studies of complexes of the type
cis- and trans-Pt(amine)2(NO3)2
Fernande D. Rochon and Viorel Buculei
Abstract: Compounds of the types cis- and trans-Pt(amine)2NO3)2 have been synthesized and characterized by IR and
1
multinuclear (195Pt, 13C, and H) NMR spectroscopies. The nitrato IR bands were compared for the two isomers. The
195Pt NMR resonances of the trans complexes were observed at lower fields (avg. –1570 ppm for primary amines)
than the cis analogues (avg. –1698 ppm) for an average ∆δ value of 124 ppm. The complexes containing a secondary
amine were observed at about the same field for the cis isomers (avg. –1682 ppm) and surprisingly at much higher
1
2
fields for the trans compounds (avg. –1638 ppm). In H NMR, the coupling constants J(195Pt-1HN) are larger for the
cis isomers (avg. 67 Hz) than for the trans compounds (avg. 58 Hz). The J(195Pt-1H) are also larger for the cis com-
3
plexes (avg. 40 vs. 33 Hz). In 13C NMR, the coupling constants are also geometry dependent. The J(195Pt-13C) are
3
larger for the cis isomers (avg. 37 Hz) than for the trans compounds (avg. 28 Hz). The J(195Pt-13C) are much smaller
2
(avg. 18 Hz for the cis complexes and 16 Hz for the trans isomers).
Key words: platinum, amine, nitrato, NMR, IR.
Résumé : Des composés de types cis- et trans-Pt(amine)2(NO3)2 ont été synthétisés et caractérisés par spectroscopies
1
infrarouge et de résonance magnétique multinucléaire (195Pt, 13C et H). Les vibrations des ligands nitrato ont été com-
parées dans les deux isomères. Les signaux en RMN du 195Pt ont montré des résonances à plus hauts champs pour les
composés cis (moy. –1698 ppm pour les amines primaires) que pour les analogues trans (moy. –1570 ppm). La valeur
moyenne de ∆δ est 124 ppm. Les complexes contenant des amines secondaires ont été observés à environ le même
champ pour les isomères cis (moy. –1682 ppm) et à plus haut champ pour les composés trans (moy. –1638 ppm). En
1
2
RMN du H, les constantes de couplage J(195Pt-1HN) sont plus grandes pour les isomères cis (moy. 67 Hz) que pour
les composés trans (moy. 58 Hz). Les couplages J(195Pt-1H) sont aussi plus importants pour les complexes cis (moy.
3
40 vs. 33 Hz). En RMN du 13C, les constantes de couplage dépendent aussi de la géométrie. Les valeurs J(195Pt-13C)
3
sont plus grandes pour les isomèrs cis (moy. 37 Hz) que pour les composés trans (moy. 28 Hz). Les constantes
2J(195Pt-13C) sont beaucoup plus petites (moy. 18 Hz pour les complexes cis et 16 Hz pour les isomères trans).
Mots clés : platine, amine, nitrato, IR, RMN. Rochon and Buculei 532
Introduction
portant to study the hydrolysis reactions of a complex before
its development as an anticancer drug.
The antitumor compound cisplatin (cis-Pt(NH3)2Cl2) is
the most widely used anticancer drug today. Its mechanism
of action involves its hydrolysis inside the cells, where the
pH is neutral and the chloride ion concentration is low. In
these conditions, cis-Pt(NH3)2Cl2 becomes aquated, produc-
ing different ionic species that can bind to DNA (1) leading
to the eventual destruction of the cell. One of these species
is the diaqua complex cis-[Pt(NH3)2(OH2)2]2+, which, be-
cause of the neutral pH inside the cells, will exist predomi-
nantly in the form cis-[Pt(NH3)2(OH)(OH2)]+ (2). The latter
species has been shown in laboratories to produce different
oligomeric species, which have been characterized by 195Pt
NMR (3–5) and by crystallographic methods (6–10). Some
of these species are toxic and could be partially responsible
for the toxicity of cisplatin in humans. Therefore, it is im-
Platinum complexes with amines are potent antitumor
agents. Some compounds have shown much better antitumor
properties than cis-Pt(NH3)2Cl2, but several are too insoluble
to become useful drugs.
Our research group has undertaken a systematic study of
complexes of the types cis- and trans-Pt(amine)2I2. The
compounds have been studied by various spectroscopic tech-
niques and by crystallography (11). We have characterized
these products to study their hydrolysis reactions. However,
the solubility of these complexes in water is very low. Sub-
stitution of the halides by nitrato ligands leads to a much
greater solubility in water. A method for the synthesis of
Pt(amine)2(NO3)2 has been published for a few amines (12),
but the complexes were characterized only by elemental
1
analysis, IR spectroscopy, and by H NMR.
Received 31 July 2003. Published on the NRC Research Press Web site at http://canjchem.nrc.ca on 25 March 2004.
F.D. Rochon1 and V. Buculei. Département de chimie, Université du Québec à Montréal, C.P. 8888, Succ. Centre-ville, Montréal,
QC H3C 3P8, Canada.
1Corresponding author (e-mail: rochon.fernande@uqam.ca).
Can. J. Chem. 82: 524–532 (2004)
doi: 10.1139/V04-012
© 2004 NRC Canada

Rochon and Buculei
525
Several complexes of the types cis- and trans-
Pt(amine)2(NO3)2 have now been synthesized in our labora-
tories and the compounds were studied by IR and multi-
1585m, ν4(NO3) 1512s, δ(C-H) 1475m, 1455s, 1360w,
ν2(NO3) 1263s, ν(C-N) 1112s, 1072m, ν1(NO3) 965F,
ν6(NO3) 783s, ν5(NO3) 702m, ν(Pt-N) 530w, 460m, ν(Pt-O)
1
1
nuclear NMR (195Pt, H, and 13C) spectroscopies. The study
330m; other bands: 1335w, 1315w, 1045w, 996m, 742s. H
of the hydrolysis and aquation reactions of these cis and
trans dinitrato compounds is underway and the results will
be published in a subsequent paper.
NMR (ppm) δ: NH 5.164s+d, 2J(195Pt-NH) = 68 Hz,
H1 2.763tq, 3J(1H-1H) = 7.2 Hz and 6.6 Hz, H2 1.308t,
3J(1H-1H) = 6.9 Hz. 13C NMR (ppm) δ: C1 43.172, 2J(195Pt-
3
C1) = 24 Hz, C2 15.776, J(195Pt-C2) = 42 Hz.
Experimental
cis-Pt(n-PrNH2)2(NO3)2
Yield: 78%; dec 107–123 °C. IR (cm–1): ν(N-H) 3260s,
3220s, ν(C-H) 2965s, 2925m, 2865w, δ(N-H) 1575m,
ν4(NO3) 1515s, δ(C-H) 1465s, 1365s, ν2(NO3) 1270s, ν(C-N)
1160m, 1110m, 1080w, ν1(NO3) 962s, ν6(NO3) 783m,
ν5(NO3) 702w, ν(Pt-N) 435m, ν(Pt-O) 332m; other bands:
1000s, 820s, 390w. 1H NMR (ppm) δ: NH 5.160s+d,
2J(195Pt-NH) = 68 Hz, H1 2.682tt, 3J(1H-1H) = 7.5 Hz,
Potassium tetrachloroplatinate(II) was purchased from
Johnson Matthey and was recrystallized in water before use.
The amine ligands were obtained from Aldrich, while silver
nitrate was purchased from Anachemia. Deuterated acetone
was acquired from CDN Isotopes.
The IR spectra were recorded between 4000 and 270 cm–1
as KBr pellets, on a PerkinElmer 783 grating spectrometer.
The decomposition points were measured on a Fisher-Johns
instrument. The NMR spectra were measured on a Varian
Gemini 300BB in acetone. The fields were 300.075, 75.460,
3
6.9 Hz, H2 1.774tq, J(1H-1H) = 7.5 Hz, 7.2 Hz, H3 0.933t,
3J(1H-1H) = 7.2 Hz. 13C NMR (ppm) δ: C1 50.017, 2J(195Pt-
C1) = 20 Hz, C2 24.336, 3J(195Pt-C2) = 40 Hz, C3 11.177.
1
and 64.395 MHz for H, 13C, and 195Pt, respectively. The ac-
1
etone peaks were used as an internal standard for H NMR
cis-Pt(n-BuNH2)2(NO3)2
(2.04 ppm) and 13C NMR (29.8 ppm). For the 195Pt spectra,
K2[PtCl4] (in D2O with KCl, adjusted at –1628 ppm from
K2[PtCl6] whose δ(Pt) = 0 ppm) was the external standard.
Yield: 72%; dec 99–110 °C. IR (cm–1): ν(N-H) 3280s,
3245s, 3145m, ν(C-H) 2955s, 2925m, 2880w, δ(N-H)
1590m, ν4(NO3) 1513s, δ(C-H) 1480s, 1465s, 1395w,
ν2(NO3) 1265s, ν(C-N) 1115m, 1075m, 1050m, ν1(NO3)
965s, ν6(NO3) 786m, ν5(NO3) 703w, ν(Pt-N) 530w, 465m,
Synthesis
1
ν(Pt-O) 330m; other bands: 1000s, 900w, 885m, 745m. H
NMR (ppm) δ: NH 5.153s+d, 2J(195Pt-NH) = 66 Hz,
The complexes Pt(amine)2I2 were synthesized as recently
published (11). The dinitrato complexes were prepared ac-
cording to a modified version of a published method de-
scribed for other ligands (12). The complexes Pt(amine)2I2
(0.5 mmol) were dissolved in a minimum quantity of ace-
tone (8 mL). A slight excess of AgNO3 was added and the
mixture was stirred in the dark and at lower temperature
(5 °C) until a colorless solution (with a yellow precipitate)
was obtained. The precipitate was filtered out and the solu-
tion was evaporated to dryness. The white residue was dis-
solved in 5 mL of acetone and filtered again to remove the
last traces of AgI and AgNO3. Diethyl ether was added and
the mixture was cooled several hours until precipitation was
complete. The precipitate was filtered, washed with diethyl-
ether, and dried under vacuum.
3
3
H1 2.719tt, J(1H-1H) = 7.2 Hz, 6.6 Hz, H2 1.745tt, J(1H-
1H) = 7.2 Hz, 6.9 Hz, H3 1.376tq, 3J(1H-1H) = 7.5 Hz,
7.2 Hz, H4 0.900t, J(1H-1H) = 7.2 Hz. 13C NMR (ppm) δ:
3
2
3
C1 48.028, J(195Pt-C1) = 21 Hz, C2 33.199, J(195Pt-C2) =
39 Hz, C3 20.344, C4 13.970.
cis-Pt(i-PrNH2)2(NO3)2
Yield: 73%; dec 136–151 °C. IR (cm–1): ν(N-H) 3260s,
3215s, 3150w, ν(C-H) 2965s, 2920m, 2870w, δ(N-H)
1580m, ν4(NO3) 1518s, δ(C-H) 1467s, 1395m, 1370m,
ν2(NO3) 1270s, ν(C-N) 1155m, 1110s, 1085w, ν1(NO3) 960s,
ν6(NO3) 782m, ν5(NO3) 702m, ν(Pt-N) 440m, ν(Pt-O) 330m;
1
other bands: 1350w, 1000s, 820m, 392w. H NMR (ppm) δ:
2
3
NH 5.088s+d, J(195Pt-NH) = 67 Hz, H1 2.993thept, J(1H-
1H) = 6.6 Hz, 6.3 Hz, 3J(195Pt-H1) = 39 Hz, H221.397d,
3J(1H-1H) = 6.3 Hz. 13C NMR (ppm) δ: C1 50.123, J(195Pt-
The notation of Nakamoto (13) was used for the IR as-
signments of the nitrato ligands.
C1) = 22 Hz, C2 23.198, J(195Pt-C2) = 30 Hz. Anal. calcd.
3
cis-Pt(MeNH2)2(NO3)2
(%): C 16.48, H 4.15, N 12.81; found (%): C 16.95, H 4.23,
N 12.38.
Yield: 75%; dec 132–150 °C. IR (cm–1): ν(N-H) 3280s,
3255s, 3230s, ν(C-H) 2995w, 2950m, δ(N-H) 1603m,
ν4(NO3) 1502s, δ(C-H) 1420w, 1395m, 1363m, ν2(NO3)
1261s, ν(C-N) 1103m, 1095s, ν1(NO3) 965s, ν6(NO3) 785m,
ν5(NO3) 703m, ν(Pt-N) 535w, 515f, ν(Pt-O) 335m; other
cis-Pt(i-BuNH2)2(NO3)2
Yield: 73%; dec 105–124 °C. IR (cm–1): ν(N-H) 3280s,
3250m, 3230s, 3135w, ν(C-H) 2970m, 2930m, 2880w, δ(N-
H) 1590m, ν4(NO3) 1503s, δ(C-H) 1460w, 1360m, ν2(NO3)
1263s, ν(C-N) 1100m, 1050w, ν1(NO3) 949s, ν6(NO3) 780m,
ν5(NO3) 710s, ν(Pt-O) 335m; other bands: 1015w, 833w,
1
band: 990s, 755m. H NMR (ppm) δ: NH 5.177s+d, 2J(195Pt-
NH) = 69 Hz, H1 2.466t+d, J(1H-1H) = 6.3 Hz, J(195Pt-
3
3
H1) = 47 Hz. 13C NMR (ppm) δ: C1 34.460, J(195Pt-C1) =
2
2
698m, 613w. 1H NMR (ppm) δ: NH 5.157s+d, J(195Pt-
25 Hz. Anal. calcd. (%): C 6.30, H 2.64, N 14.70; found
(%): C 6.47, H 2.78, N 14.73.
NH) = 65 Hz, H1 2.594td, 3J(1H-1H) = 7.5 Hz, 6.9 Hz,
3
3J(195Pt-H1) = 37 Hz, H2 2.096thept, J(1H-1H) = 6.9 Hz,
3
6.6 Hz, H3 20.953d, J(1H-1H) = 6.6 Hz. 13C NMR (ppm) δ:
cis-Pt(EtNH2)2(NO3)2
Yield: 73%; dec 108–132 °C. IR (cm–1): ν(N-H) 3260s,
3245s, 3150m, ν(C-H) 2965s, 2925m, 2865m, δ(N-H)
C1 55.693, J(195Pt-C1) = 21 Hz, C2 hidden by the solvent,
C3 20.101.
© 2004 NRC Canada

526
Can. J. Chem. Vol. 82, 2004
cis-Pt(sec-BuNH2)2(NO3)2
trans-Pt(n-PrNH2)2(NO3)2
Yield: 79%; dec 138–152 °C. IR (cm–1): ν(N-H) 3260s,
3230s, 3210s, ν(C-H) 2980s, 2930m, 2880w, δ(N-H) 1580m,
ν4(NO3) 1508s, δ(C-H) 1430w, 1385s, ν2(NO3) 1261s, ν(C-
N) 1100w, 1080m, 1055w, ν1(NO3), 965s, ν6(NO3) 785m,
ν5(NO3) 700w, ν(Pt-N) 410w, ν(Pt-O) 338m; other bands:
1025m, 885w, 835w, 760w. 1H NMR (ppm) δ: NH 4.759s+d,
2J(195Pt-NH) = 57 Hz, H1 2.584tt, 3J(1H-1H) = 7.5 Hz,
Yield: 79%; dec 101–118 °C. IR (cm–1): ν(N-H) 3225s,
3145m, ν(C-H) 2960s, 2915m, 2870w, δ(N-H) 1600m,
ν4(NO3) 1509s, δ(C-H) 1470s, 1380s, ν2(NO3) 1278s, ν(C-N)
1140w, 1115m, 1075m, ν1(NO3) 965s, ν6(NO3) 788m,
ν5(NO3) 702w, ν(Pt-N) 460w, 430w, ν(Pt-O) 335m; other
bands: 1000m, 895w, 835w. 1H NMR (ppm) δ: NH
2
3
5.117s+d, J(195Pt-NH) = 65 Hz, H1 2.712ttq, J(1H-1H) =
3
6.9 Hz, H2 1.805 tq, J(1H-1H) = 7.5 Hz, 7.2 Hz, H3 0.938t,
3
7.2 Hz, 6.9 Hz, 6.6 Hz, J(195Pt-H1) = 35 Hz, H2 1.543dq,
3J(1H-1H) = 7.2 Hz. 13C NMR (ppm) δ: C1 48.241, 2J(195Pt-
C1) = 16 Hz, C2 24.048, 3J(195Pt-C2) = 29 Hz, C3 11.329.
3J(1H-1H) = 7.2 Hz, 6.6 Hz, H2′ 1.404d, J(1H-1H) = 6.6 Hz,
3
H3 0.941t, 3J(1H-1H) = 7.2 Hz. 13C NMR (ppm) δ:
2
C1 55.405, J(195Pt-C1) = 20 Hz, C2 hidden by the solvent,
C2′ 20.101, 3J(195Pt-C2′) = 29 Hz, C3 10.631.
trans-Pt(n-BuNH2)2(NO3)2
Yield: 83%; dec 135–146 °C. IR (cm–1): ν(N-H) 3240s,
3140m, ν(C-H) 2960s, 2930m, 2870m, δ(N-H) 1595s,
ν4(NO3) 1510s, δ(C-H) 1480s, 1385s, ν2(NO3) 1260s, ν(C-N)
1150w, 1115w, 1075w, ν1(NO3) 962s, ν6(NO3) 788w,
ν5(NO3) 702w, ν(Pt-N) 460w, ν(Pt-O) 337w; other bands:
1000s, 895w, 830w. 1H NMR (ppm) δ: NH 4.746s+d,
2J(195Pt-NH) = 56 Hz, H1 2.622tt, 3J(1H-1H) = 7.5 Hz,
cis-Pt(Me2NH)2(NO3)2
Yield: 72%; dec 121–147 °C. IR (cm–1): ν(N-H) 3280s,
3225s, 3135w, ν(C-H) 2930s, 2865s, δ(N-H) 1585m,
ν4(NO3) 1503s, δ(C-H) 1460m, 1370s, ν2(NO3) 1260s, ν(C-
N) 1170m, 1125m, ν1(NO3) 949s, ν6(NO3) 780s, ν5(NO3)
710s, ν(Pt-N) 440w, 405w, ν(Pt-O) 342m; other bands:
1030m, 830w, 820w, 603w. 1H NMR (ppm) δ: NH 5.998s+d,
3
6.9 Hz, H2 1.787tt, J(1H-1H) = 7.5 Hz, 7.2 Hz, H3 1.385tq,
3J(1H-1H) = 7.5 Hz, 7.2 Hz, H4 0.910t, J(1H-1H) = 7.2 Hz.
3
2J(195Pt-NH) = 69 Hz, H1 2.650d+d, J(1H-1H) = 5.7 Hz,
3
13C NMR (ppm) δ: C1 46.146, 2J(195Pt-C1) = 16 Hz,
C2 32.942, 3J(195Pt-C2) = 26 Hz, C3 20.466, C4 14.030. Anal.
calcd. (%): C 20.65, H 4.77, N 12.04; found: C 21.09, H
5.17, N 12.03.
3J(195Pt-H1) = 40 Hz. 13C NMR (ppm): C1 44.553, J(195Pt-
2
C1) = 25 Hz.
cis-Pt(Et2NH)2(NO3)2
trans-Pt(i-PrNH2)2(NO3)2
This compound was not synthesized from cis-
Pt(Et2NH)2I2 as the other cis-dinitrato complexes. The com-
pound trans-Pt(Et2NH)2I2 contained about 30% of the cis
isomer. A mixture of the cis and trans isomers of
Yield: 80%; dec 144–163 °C. IR (cm–1): ν(N-H) 3305s,
ν(C-H) 3080w, 3060w, 3010m, δ(N-H) 1575s, ν4(NO3)
1510s, δ(C-H) 1475w, 1450m, 1395w, ν2(NO3) 1266s, ν(C-
N) 1170m, 1130s, 1090w, 1055s, ν1(NO3) 961s, ν6(NO3)
795m, ν5(NO3) 700w, ν(Pt-N) 550m, ν(Pt-O) 375m; other
bands: 1000s, 930m, 750m. 1H NMR (ppm) δ: NH 4.738s+d,
1
Pt(Et2NH)2(NO3)2 was obtained. H NMR for the cis isomer
2
(ppm) δ: NH 5.836s+d, J(195Pt-NH) = 67 Hz, H1 3.046tq,
3
3J(1H-1H) = 7.2 Hz, 6.6 Hz, H2 1.368t, J(1H-1H) = 6.6 Hz.
2J(195Pt-NH) = 59 Hz, H1 2.933thept, J(1H-1H) = 7.2 Hz,
3
13C NMR for the cis isomer: C1 51.350, 2J(195Pt-C1) =
3
6.6 Hz, H2 1.380d, J(1H-1H) = 6.6 Hz. 13C NMR (ppm) δ:
3
22 Hz, C2 15.220, J(195Pt-C2) = 39 Hz.
2
3
C1 48.514, J(195Pt-C1) = 15 Hz, C2 23.076, J(195Pt-C2) =
26 Hz.
trans-Pt(MeNH2)2(NO3)2
Yield: 80%; dec 137–163 °C. IR (cm–1): ν(N-H) 3260s,
3240s, 3150s, ν(C-H) 2985w, 2940m, 2890w, δ(N-H) 1595s,
ν4(NO3) 1503s, δ(C-H) 1455m, 1420w, 1355m, ν2(NO3)
1251s, ν(C-N) 1095s, 1055s, ν1(NO3) 966s, ν6(NO3) 775s,
ν5(NO3) 709s, ν(Pt-N) 505m, ν(Pt-O) 350m; other bands:
trans-Pt(i-BuNH2)2(NO3)2
Yield: 78%; dec 128–141 °C. IR (cm–1): ν(N-H) 3280s,
3250s, 3150w, ν(C-H) 2970m, 2930m, 2880w, δ(N-H)
1585m, ν4(NO3) 1510s, δ(C-H) 1480m, 1465m, 1385s,
ν2(NO3) 1266s, ν(C-N) 1115m, 1070w, ν1(NO3) 965m,
ν6(NO3) 785w, ν5(NO3) 700w, ν(Pt-N) 470w, ν(Pt-O) 345m,
2
1020m. 1H NMR (ppm) δ: NH 4.737s+d, J(195Pt-NH) =
57 Hz, H1 2.327 t+d, 3J(1H-1H) = 6.6 Hz, 3J(195Pt-H1) =
32 Hz. 13C NMR (ppm) δ: C1 32.380, 2J(195Pt-C1) = 20 Hz.
1
other bands: 1045w, 1000s, 880w, 830w, 745m. H NMR
2
(ppm) δ: NH 4.714s+d, J(195Pt-NH) = 57 Hz, H1 2.481td,
3J(1H-1H) = 6.9 Hz, 6.3 Hz, H2 2.131thept, 3J(1H-1H) =
6.6 Hz, 6.3 Hz, H3 0.962d, J(1H-1H) = 6.6 Hz. 13C NMR
3
trans-Pt(EtNH2)2(NO3)2
2
(ppm) δ: C1 55.948, J(195Pt-C1) = 15 Hz, C2 hidden by the
Yield: 83%; dec 120–157 °C. IR (cm–1): ν(N-H) 3280s,
3240s, 3150m, ν(C-H) 2960m, 2930w, 2870w, δ(N-H)
1585s, ν4(NO3) 1512s, δ(C-H) 1485m, 1470m, 1380m,
ν2(NO3) 1268s, ν(C-N) 1115m, 1075w, 1050w, ν1(NO3)
967s, ν6(NO3) 785w, ν5(NO3) 705w, ν(Pt-N) 465w, ν(Pt-O)
solvent, C3 20.223.
trans-Pt(sec-BuNH2)2(NO3)2
Yield: 85%; dec 132–148 °C. IR (cm–1): ν(N-H) 3260s,
3230s, 3160m, ν(C-H) 2960s, 2940m, 2870w, δ(N-H)
1600m, ν4(NO3) 1502s, δ(C-H) 1455m, 1370s, ν2(NO3)
1255s, ν(C-N) 1150w, 1122m, 1075m, ν1(NO3) 967s,
ν6(NO3) 788w, ν5(NO3) 710w, ν(Pt-N) 470w, ν(Pt-O) 345m;
1
333m; other bands: 1000s, 885w, 740m. H NMR (ppm) δ:
2
NH 4.764s+d, J(195Pt-NH) = 59 Hz, H1 2.665tq, 3J(1H-
3
1H) = 7.5 Hz, 7.2 Hz, H2 21.321t, J(1H-1H) = 7.2 Hz. 13C
NMR (ppm) δ: C1 41.229, J(195Pt-C1) = 19 Hz, C2 15.487,
3J(195Pt-C2) = 30 Hz. Anal. calcd. (%): C 11.74, H 3.45, N
13.69; found: C 11.69, H 3.32, N 13.06.
1
other bands: 1035w, 900w, 830w. H NMR (ppm) δ: NH
2
3
4.720s+d, J(195Pt-NH) = 58 Hz, H1 2.662ttq, J(1H-1H) =
© 2004 NRC Canada

Rochon and Buculei
527
3
7.2 Hz, 6.6 Hz, 6.3 Hz, H2 1.596dq, J(1H-1H) = 6.9 Hz,
BuNH2), sec-butylamine (sec-BuNH2), dimethylamine
(Me2NH), and trans compounds with tert-butylamine (t-
BuNH2) and diethylamine (Et2NH) were synthesized.
6.6 Hz, H2′ 1.381d, 3J(1H-1H) = 6,6 Hz, H3 0.951t, 3J(1H-1H) =
2
6.9 Hz. 13C NMR (ppm) δ: C1 54.008, J(195Pt-C1) = 15 Hz,
C2 hidden by the solvent, C2′ 20.041, 3J(195Pt-C2′) = 27 Hz,
The use of a slight excess of silver nitrate increased the
yields. When the reactions were performed at room tempera-
ture, oily compounds were obtained and the products de-
composed quite rapidly. The yields were also very low. Most
dinitrato complexes are stable when kept in the dark and at
lower temperature. Even in these conditions, a few com-
pounds decomposed fairly rapidly to a black material. The
complex cis-Pt(i-BuNH2)2(NO3)2 decomposed after a few
hours. All the IR and NMR spectra were measured on fresh
samples. The compound trans-Pt(Et2NH)2(NO3)2 was not
pure, since two series of signals were observed in NMR (1H,
13C, and 195Pt) spectroscopy. The second compound was as-
sumed to be the cis analogue, since the starting material
trans-Pt(Et2NH)2I2 contained some cis isomers as described
in a previous paper (11).
C3 10.585.
trans-Pt(t-BuNH2)2(NO3)2
Yield: 76%; dec 111–134 °C. IR (cm–1): ν(N-H) 3270s,
3250s, 3170m, ν(C-H) 2980m, 2930w, 2880w, δ(N-H)
1600s, ν4(NO3) 1495s, δ(C-H) 1455w, 1380m, 1355m,
ν2(NO3) 1265s, ν(C-N) 1080s, ν1(NO3) 970s, ν6(NO3) 783s,
ν5(NO3) 710w, ν(Pt-O) 345m; other bands: 1030s, 880w,
740w, 605w. 1H NMR (ppm) δ: NH 4.808s+d, 2J(195Pt-
NH) = 59 Hz, H2 1.385s, J(195Pt-H2) = 15 Hz. 13C NMR
4
(ppm) δ: C1 55.721, 2J(195Pt-C1) = 11 Hz, C2 31.763,
3J(195Pt-C2) = 19 Hz.
trans-Pt(Me2NH)2(NO3)2
Yield: 86%; dec 132–159 °C. IR (cm–1): ν(N-H) 3225s,
3200s, ν(C-H) 2980w, 2940m, 2920m, δ(N-H) 1540m,
ν4(NO3) 1512s, δ(C-H) 1465s, 1430w, 1395w, 1355s,
ν2(NO3) 1260s, ν(C-N) 1140m, 1095s, 1080s, ν1(NO3) 960s,
ν6(NO3) 778s, ν5(NO3) 703m, ν(Pt-N) 510m, ν(Pt-O) 347m;
other bands: 1015s, 935s, 890s, 835w. 1H NMR (ppm) δ: NH
IR spectroscopy
The IR spectra of the complexes were recorded and are
listed in the Experimental section. The notation of
Nakamoto (13) was used for the bands involving the nitrato
ligands.
5.500s+d, J(195Pt-NH) = 58 Hz, H1 2.478d+d, J(1H-1H) =
6.0 Hz, 3J(195Pt-H1) = 33 Hz. 13C NMR (ppm) δ: C1 42.883,
2J(195Pt-C1) = 18 Hz.
2
3
The symmetry of the free nitrate ion is D3h, with a bond
order of 1 1/3. However, in the monodentate-coordinated
nitrato ligand, the N—O(Pt) bond order is close to 1. The π
electronic density is then delocalized on only two N—O
bonds resulting in a bond order of 1 1/2 for the two bonds.
trans-Pt(Et2NH)2(NO3)2
This compound was found to be a cis–trans mixture.
Yield: 80%; dec 124–143 °C. IR (cm–1): ν(N-H) 3280s,
3175m, ν(C-H) 2980m, 2885m, δ(N-H) 1575s, ν4(NO3)
1510s, δ(C-H) 1475m, 1455w, 1375m, ν2(NO3) 1267s, ν(C-
N) 1210m, 1065w, ν1(NO3) 964s, ν6(NO3) 780w, ν5(NO3)
705w, other bands: 1005s, 865w, 755w. 1H NMR of the trans
isomer (ppm) δ: NH 5.519s+d, 2J(195Pt-NH) = 58 Hz,
H1 2.955tq, 3J(1H-1H) = 7.5 Hz, 6.9 Hz, H2 1.344t, 3J(1H-1H)
= 6.9 Hz. 13C NMR of the trans isomer (ppm) δ: C1 50.834,
–
The approximate symmetry of coordinated NO3 is C2v. The
reduction in the N—O(Pt) bond order is clearly observed by
–
comparing the stretching band ν1 (13) in free NO3
(1049 cm–1) with the one observed in CH3ONO2 (854 cm–1),
a purely covalent compound (14). It has been suggested that
the position of the ν1 band gives important information on
the covalent character of the Pt—O bond (15). Because of
the reduction in symmetry of the coordinated nitrato ligand,
some of the vibration modes, which were degenerate in the
free ion, will be split. This is the case for the ν3 stretching
mode in D3h (E), which will separate into the ν2 (A1) and ν4
(B2) stretching modes in C2v symmetry (13). The energy dif-
ference between the two latter modes (∆ = ν4 – ν2) should
also give additional information on the covalent character of
the Pt—O bond (14, 15). For ionic nitrate ∆ is 0 cm–1, while
it is 385 cm–1 in CH3ONO2.
2J(195Pt-C1) = 14 Hz, C2 15.099, J(195Pt-C2) = 28 Hz.
3
Results and discussion
The dinitrato complexes were prepared by the reaction of
the diiodo complexes with a slight excess (10%) of silver ni-
trate in acetone similar to a published method (12).
Pt(amine)2I2 + 2AgNO3 → Pt(amine)2(NO3)2 + 2AgI↓
The values of ∆ as well as the energy difference (∆ν1) be-
tween the ν1 band for free nitrate and the coordinated nitrato
ligands are shown in Table 1. The average value ∆(ν4 – ν2) is
243 cm–1 in the cis complexes and 246 cm–1 in the trans iso-
mers. The difference is not significant. We have calculated
this ∆(ν4 – ν2) value for a few dinitrato complexes reported
in the literature. These values for cis-PtA2(NO3)2 are
230 cm–1 for A = NH3 (16), 227 cm–1 for NH2CH3 (12),
214 cm–1 for NH2(C6H11) (12), 226 cm–1 for 4-
hydroxymethylpyridine (12), and 238 cm–1 for NH2(CH2Ph)
(12), and 245 cm–1 for A2 = bipy and 240 cm–1 for phen
(14). These results are close to our values. In a study on cis-
and trans-Pt(Ypy)2NO3)2, (Ypy = pyridine derivative) the
average value for ∆(ν4 – ν2) was found to be higher in the
The diiodo complexes dissolved in acetone resulting in a
yellow solution. Silver nitrate is only slightly soluble in ace-
tone. The reaction was performed in the dark and at a lower
temperature in ice, to reduce decomposition. The published
method (12), which was used for other ligands, required 5–
20 min of stirring time. The reaction time for our ligands
varied between a few hours to 2 days depending on the
amine. After filtration and the purification process, the white
dinitrato complexes were isolated and characterized. The cis
or trans geometry was retained during the reaction. The cis
and trans compounds with amine = methylamine (MeNH2),
ethylamine (EtNH2), n-propylamine (n-PrNH2), n-butylamine
(n-BuNH2), iso-propylamine (i-PrNH2), iso-butylamine (i-
© 2004 NRC Canada

528
Can. J. Chem. Vol. 82, 2004
Table 1. ∆(υ4 – υ2) and ∆υ1 (cm–1) (as defined in the text) of the
complexes of Pt(amine)2(NO3)2.
Table 2. υ(Pt-O) (cm–1) vibrations in Pt(amine)2(NO3)2 and some
examples from the literature.
cis-Pt(amine)2(NO3)2
trans-Pt(amine)2(NO3)2
Amine
cis
trans
Reference
Amine
∆(υ4 – υ2)
∆υ1
84
∆(υ4 – υ2)
∆υ1
NH3
330
332
18
19
19
19
MeNH2
MeNH2
241
249
245
248
248
240
231
252
244
247
250
244
244
247
230
252
83
82
84
87
88
84
82
79
89
C6H11NH2
PhCH2NH2
2,2′-Bipyridine
4-Hydroxymethylpyridine 338, 346
Pyridine
334, 340 345
350, 360
EtNH2
84
n-PrNH2
n-BuNH2
i-PrNH2
i-BuNH2
sec-BuNH2
t-BuNH2
Me2NH
87
340, 350
19
19
17
19
17
17
17
17
17
84
89
341, 325 360
338
338
340, 350 330
330, 339 349
343
100
84
4-Picoline
350
353
2-Picoline
3-Picoline
2,4-Lutidine
3,5-Lutidine
MeNH2
243
100
340
330, 337 351
trans compounds (264 cm–1) than in the cis isomers
(233 cm–1) (17).
335
330
332
330
330
335
335
350
EtNH2
333
The position of ν1 for our compounds is also not very dif-
ferent in the two geometries (avg. ∆υ1 89 cm–1 for cis and
84 cm–1 for trans). For the compounds cis- and trans-
Pt(Ypy)2NO3)2, the ν1 band was found to be less energetic in
the trans complexes (avg. ∆υ1 = 120 vs. 90 cm–1 for the cis
isomers), suggesting a more covalent character for the Pt—O
bonds in the trans geometry (17). Our results on the amine
system seem to indicate that the covalency of the Pt—O
bonds in the cis and trans compounds are not very different.
The stretching energy of a more covalent bond should in-
crease and these results can be compared with the energies
of the ν(Pt-O) vibrations. The skeletal symmetry around the
platinum atom is C2v for the cis complexes and D2h for the
trans isomers. Two ν(Pt-O) bands are expected for the cis
compounds and one for the trans complexes, according to
group theory. Our assignment of the υ(Pt-O) bonds was
made according to some published works (17–19). These
bands are shown in Table 2 along with the results published
in the literature. Some of the published work on the cis com-
plexes have shown two ν(Pt-O) absorption bands, while oth-
ers have shown only one. We have observed only one band
for both isomers. The position of the band is not very differ-
ent for the different isomers, although it appears slightly
larger for the trans compounds (avg. 346 vs. 333 cm–1).
These results seem to agree with our conclusion reached
above from the study of the nitrato ν1 band and ∆(ν4 – ν2)
values. There seems to be no important difference between
the two isomers. These ν(Pt-O) vibrations are not very ener-
getic and are close to the ν(Pt-Cl) vibrations. They are diffi-
cult to assign with certainty, since they are quite weak. It is
also possible that they are not pure and might couple with
other vibrations.
n-PrNH2
n-BuNH2
i-PrNH2
i-BuNH2
sec-BuNH2
t-BuNH2
Me2NH
Et2NH
338
337
375
345
345
345
342
347
340 (Mixture)
nitrato ligand compared to the iodo ligand could increase the
energy of the ν(Pt-N) vibrations. The trans influence of the
iodo ligand is larger than the one of the nitrato ligand, which
should also increase the energy of the ν(Pt-N) vibrations in
the cis-dinitrato complexes. The trans compounds with tert-
butylamine and diethylamine and the cis-iso-butylamine
compound did not show any band in the ν(Pt-N) region.
195Pt NMR spectroscopy
The 195Pt NMR spectra of the dinitrato complexes were
measured in acetone and the chemical shifts are listed in Ta-
ble 4 as well as the pKa of the protonated ligands (23) and
the proton affinity of the amines (24–27). To determine if
the nitrato ligands are partly dissociated in acetone, the con-
ductivity of several cis and trans complexes were measured
in acetone. The results have shown that there is no apprecia-
ble solvolysis of the compounds. The molar conductivity
values varied between 0.03 and 0.06 S cm2/mol. The corre-
sponding values for several cesium salts were much larger.
Therefore, the chemical shifts in Table 4 correspond to those
of the dinitrato complexes.
The ν(Pt-N) bands were assigned based on some pub-
lished works (13, 19–22). Two vibration modes are expected
for the cis compounds and only one for the trans isomers.
Our assignments are shown in Table 3. For most complexes,
two bands were observed for the cis complexes while only
one was shown by the trans isomers. The energies of these
bands are slightly higher than those of the corresponding
iodo complexes (11), suggesting that the covalency of the
Pt—N bonds are greater in the dinitrato compounds than in
the diiodo analogues. The reduced polarizability of the
The cis isomers were observed at higher fields than their
trans analogues. The complex trans-Pt(Et2NH)2(NO3)2 con-
tained a second compound, which we have assigned to the
cis isomer, since the starting material trans-Pt(Et2NH)2I2
was shown to contain some cis compound (11). The signal
observed at higher field was assumed to be the cis com-
pound as observed for the other ligands. The difference be-
tween the cis and trans isomers is larger for the primary
amines (avg. 125 ppm) than for the secondary amines (avg.
© 2004 NRC Canada

Rochon and Buculei
529
Table 3. υ(Pt-N) (cm–1) bands for the com-
plexes of Pt(amine)2(NO3)2.
Table 4. δ(195Pt) and ∆δ = δcis – δtrans (ppm) of the complexes of
Pt(amine)2(NO3)2. (PA = proton affinity, kJ/mole).
Amine
cis
trans
Amine PA pKa cis trans
9.25
∆δ
νs
νas
νas
NH3 (DMF) 854 –1592 (28) –1413 (28) –179
MeNH2
EtNH2
914
930
933
924
10.62 –1713
10.67 –1707
10.71 –1694
10.78 –1699
10.63 –1698
10.72 –1694
10.56 –1683
10.68
–1608
–1579
–1577
–1574
–1558
–1572
–1548
–1540
–1675
–1601
–105
–128
–117
–125
–140
–122
–135
562
535
530
558
515
460
435
465
440
NH3 (28)
MeNH2
505
465
410
460
550
470
470
510
EtNH2
n-PrNH2
n-BuNH2
i-PrNH2
i-BuNH2
sec-BuNH2
t-BuNH2
Me2NH
Et2NH
n-PrNH2
n-BuNH2
i-PrNH2
i-BuNH2
sec-BuNH2
Me2NH
530
460
440
430
405
10.73 –1696
11.04 –1668*
–21
–67
Note: PA is the proton affinity (kJ/mol).
*Indicates an impurity in the trans compound (see text).
44 ppm). Our results are in agreement with those of the NH3
complexes (28).
Surprisingly, the trans isomers of the complexes contain-
ing the secondary amines were observed at higher fields than
the compounds containing the primary amines, while the cis
compounds were observed at about the same fields. For
square-planar complexes, the molecules of solvent can nor-
mally approach and weakly bind to the Pt atom on both
sides of the coordination plane. For complexes containing
more bulky ligands close to the binding site, the molecules
of solvent cannot approach the Pt atom easily, resulting in a
decrease of the electronic density around the Pt nucleus.
This solvent factor is very important for solvents like water
that can coordinate to platinum. However, the dinitrato com-
plexes were measured in deuterated acetone, a solvent that
could coordinate to Pt, but not as easily as water. Therefore
the solvent effect should be considerably reduced. Further-
more, the reduced solvation for crowded ligands is less im-
portant in trans compounds, where the two ligands are far
from each other.
Nitrato ligands are more bulky than iodo or chloro lig-
ands. Therefore, the presence of the nitrato ligands should
have an influence of the solvation of the Pt atom. There are
two Pt NMR studies in the literature on dinitrato com-
pounds. The results for the NH3 (28) complexes are shown
in Table 4. NH3 complexes are usually observed at lower
fields than amine complexes. The other published paper is
on a series of pyridine complexes (17). In these compounds,
the cis compounds were observed between –1485 and
−1532 ppm, while the trans isomers were reported between
−1402 and –1481 ppm, with ∆δ (cis–trans) = –43 to –
83 ppm. The compounds with ortho substituents were ob-
served at lower fields than the others, probably because of
reduced solvation around the Pt atom, due to a more limited
rotation of the pyridine ligand around the Pt—N bond (17).
The ortho substituents are mainly located on top of the Pt
atom and prevent the approach of the molecules of solvent.
Our results on the diamine complexes have shown values of
∆δ (cis–trans) from –105 to –140 ppm for the primary
amines. The difference is larger than those published for the
pyridine complexes (17), but smaller than the one for the
NH3 compounds (28), where it is 179 ppm. Our values for
the secondary amines (avg. 44 ppm) are closer to those re-
ported for the pyridine system (17).
There seems to be a slight deshielding effect on the Pt
atom as the bulkiness on the primary amine is increased.
This is probably due to a reduction in the solvation of the
metal centre. The difference in chemical shifts is smaller in
the cis compounds (30 ppm) than in the trans isomers
(68 ppm) for the complexes containing primary amines.
Attempts were made in the literature (29–31) to correlate
the 195Pt chemical shifts with the basicity of the amine li-
gands to study the nature of the Pt–amine bond. Contrary to
pyridine, amines cannot accept π electron density from the
metal. Therefore, in the formation of the σ(amine → Pt)
bond, electron density is transferred from the amine ligand
to the platinum nucleus, resulting in a shielding on the 195Pt
nucleus and a deshielding effect on the ligands (1H and 13C
NMR signals). A weak relation between δ(195Pt) and the ba-
sicity of the ligands was reported for complexes of the type
cis- and trans-Pt(Ypy)2X2 (X = Cl– or I–) (29), but the dis-
persion around the straight line was fairly large. For pyridine
derivatives, the 195Pt chemical shifts seem to depend more
on the position of the CH3 substituents then on the basicity
of the ligand. To verify the influence of the basicity of the
amine on the δ(Pt) values, the latter were plotted vs. the pKa
of the protonated amines. No correlation could be observed
for the cis or the trans compounds. The pKa values were
measured in a solvent (water or alcohol) and are influenced
by the presence of the substituents on the protonated N
atom. The errors on the pKa values are not negligible, espe-
cially for the primary amines where the pKa values do not
vary very much (from 10.62 to 10.78). The proton affinity
values of the amines that are measured in the gas phase,
might represent better the basicity of the ligands. But these
values are not as common as the pKa values. Figure 1 shows
the relation between the δ(Pt) and the published proton affin-
ity of the amines (24–27) for the cis and trans complexes.
The 195Pt chemical shift seems to increase slightly as the
proton affinity increases. But the difference is small, close to
the experimental errors. More data are needed to reach a
sound conclusion.
The δ(Pt) does not seem to be very influenced by the ba-
sicity of the ligands. Acetone is not an inert solvent for plati-
num, and solvation around the Pt atom is probably a more
© 2004 NRC Canada

530
Can. J. Chem. Vol. 82, 2004
Table 5. δ(1H) (ppm) and J(195Pt-H1) (Hz) of Pt(amine)2(NO3)2 in CD3COCD3.
Amine
NH
H1
H2
H3
H4 or H2′
2J(195Pt-NH)
3J(195Pt-H1)
MeNH2
cis
5.177
2.466
69
47
32
trans
cis
4.737
5.164
2.327
2.763
57
68
EtH2
1.308
trans
cis
*
trans
*
4.764
5.160
4.600
4.759
3.850
5.153
2.665
2.682
2.700
2.584
2.700
2.719
1.321
1.774
1.700
1.805
1.750
1.745
59
68
65*
57
65*
66
n-PrNH2
0.933
0.940
0.938
0.960
1.376
n-BuNH2
i-PrNH2
cis
0.900
0.910
trans
cis
4.746
5.088
2.622
2.993
1.787
1.397
1.385
56
67
trans
cis
4.738
5.157
2.933
2.594
1.380
2.096
59
65
i-BuNH2
sec-BuNH2
Me2NH
0.953
37
35
trans
cis
4.714
5.117
2.481
2.712
2.131
1.543
0.962
0.941
57
65
1.404
1.381
trans
cis
4.720
5.998
2.662
2.650
1.596
0.951
58
69
40
33
trans
trans
cis‡
5.500
4.808
2.478
58
59
t-BuNH2
1.385
1.368
1.344
Et2NH
5.836
5.519
3.046
2.955
67
58
trans
*In CDCl3 (32).
‡See text.
Fig. 1. δ(195Pt) vs. proton affinity (PA) of the amine for the com-
plexes of Pt(amine)2(NO3)2.
δ(Pt), where the cis compounds were observed at higher
fields than the corresponding trans isomers. A larger reduc-
tion of electron density on the ligand in the cis compounds
should be associated with a larger electron density on the
platinum atom (δ(Pt) at higher fields). Therefore, the σ
bonds seem stronger in the cis compounds than in the trans
isomers.
For the chiral ligand, sec-butylamine, only one series of
signals was observed in the1H NMR for both isomers. For
the compound identified as trans-Pt(Et2NH)2(NO3)2, two se-
ries of signals were observed as in 195Pt NMR. The second
series was assigned to the cis isomer as discussed above.
2
All the NH J(195Pt-1H) coupling constants could be cal-
culated. They are larger in the cis configuration where the
average value is 67 Hz compared to 58 Hz (avg.) for the
trans isomers. These values were found to be 67 Hz (cis) and
59 Hz (trans) for the corresponding diiodo complexes (11).
3
The J(195Pt-1H) coupling constants also depend on the ge-
important factor in determining the NMR chemical shifts.
The trans complexes with secondary amines have shown res-
onances at higher fields than those with primary amines, but
more complexes with secondary amines are needed before
any conclusion can be reached.
ometry of the complex. They range between 35 and 47 Hz
for the cis complexes and between 32 and 33 Hz for the
trans compounds. These values are difficult to measure,
since the signals are often multiplets of low intensity. These
values agree with those reported for other similar complexes
(11, 12, 17, 29, 33). One J(195Pt-1H2) coupling constant for
4
1H and 13C NMR spectroscopy
1
trans-Pt(t-BuNH2)2(NO3)2 could be measured (15 Hz).
The 13C NMR chemical shifts as well as the J(195Pt-13C)
coupling constants are listed in Table 6. The 13C NMR sig-
nals of C1 and C2 are more deshielded for the cis complexes
than those of the trans analogues. This is consistent with the
more upfield 195Pt chemical shifts observed for the cis com-
The H NMR chemical shifts are listed in Table 5 as well
as the published values on Pt(n-PrNH2)2(NO3)2 measured in
CDCl3 (32). These authors have also measured their com-
pounds in CD3COCD3, but only the -NH2 are reported at 5.2
(cis) and 4.7 (trans) ppm (32). These values agree with ours.
There are not many data in the literature on dinitrato amine
complexes. The NH and H1 chemical shifts of the cis com-
pounds are more deshielded than the corresponding values
for the trans isomers. These results are in agreement with the
1
plexes and with the results obtained in H NMR.
The J(195Pt-13C) and J(195Pt-13C) coupling constants are
2
3
also dependent on the geometry of the compounds. For the
© 2004 NRC Canada

Rochon and Buculei
Table 6. δ(13C) (ppm) and J(195Pt-13C) (Hz) of Pt(amine)2(NO3)2 in CD3COCD3.
531
Amine
C1
C2
C3
C4 or C2′
2J(195Pt-C1)
3J(195Pt-C2)
MeNH2
cis
34.460
25
trans
cis
32.380
43.172
20
24
EtNH2
15.776
42
trans
cis
41.229
50.017
15.487
24.336
19
20
30
40
n-PrNH2
n-BuNH2
i-PrNH2
i-BuNH2
sec-BuNH2
Me2NH
11.177
trans
cis
48.241
48.028
24.084
33.199
11.329
20.344
16
21
29
39
13.970
14.030
trans
cis
46.146
50.123
32.942
23.198
20.466
16
22
26
30
trans
cis
48.514
55.693
23.076
*
15
21
26
20.101
trans
cis
55.948
55.405
20.223
10.631
15
20
*
20.101
20.041
29
27
trans
cis
54.008
44.553
10.585
15
25
trans
trans
42.883
55.721
18
11
t-BuNH2
31.763
15.220
15.099
19
39
28
Et2NH
cis‡
51.350
50.834
22
14
trans
*Hidden by the solvent.
‡See text.
3J the average value is 37 Hz for the cis complexes and
9. R. Faggiani, B. Lippert, C.J.L. Lock, and B. Rosenberg. Inorg.
Chem. 17, 1941 (1978).
10. J.A. Stanko, L.S. Hollis, J.A. Schreifels, and J.D. Hoeschele. J.
2
28 Hz for the trans isomers. The J(195Pt-13C) coupling con-
stants are smaller, probably because of inadequate orienta-
tion of the orbitals (30) as reported for other similar
compounds. The average values are 18 Hz (cis) and 16 Hz
(trans).
For the compound identified as trans-Pt(Et2NH)2(NO3)2,
two series of signals were observed as in 195Pt and 1H NMR.
The second series was assigned to the cis isomer as dis-
cussed above. For the chiral ligand, sec-butylamine, only
one series of signals was observed in 13C NMR for both iso-
mers. For the diiodo analogues, some spectra with this
ligand have shown two series of signals (11).
Clin. Hematol. Oncol. 7, 138 (1977).
11. F.D. Rochon and V. Buculei. Inorg. Chim. Acta. In press.
12. J.-P. Souchard, F.L. Wimmer, T.B.T. Ha, and N.P. Johnson. J.
Chem. Soc. Dalton Trans. 307 (1990).
13. K. Nakamoto. Infrared and Raman spectra of inorganic and co-
ordination compounds. 5th Ed. John Wiley and Sons,
New York. 1997.
14. S. Wimmer, P. Castan, F.L. Wimmer, and N.P. Johnson. J.
Chem. Soc. Dalton Trans. 403 (1989).
15. J. R. Ferraro. J. Mol. Spectrosc. 4, 99 (1960).
16. B. Lippert, C.J.L. Lock, B. Rosenberg, and M. Zvagulis. Inorg.
Chem. 16, 1525 (1977).
17. C. Tessier and F.D. Rochon. Inorg. Chim. Acta, 322, 37
(2001).
18. T. Lind and H. Toftlund. Acta Chem. Scand. Ser. A, A36, 489
(1982).
19. T.B.T. Ha, F.L. Wimmer, J.P. Souchard, and N.P. Johnson. J.
Chem. Soc. Dalton Trans. 1251 (1990).
Acknowledgement
The authors are grateful to the Natural Sciences and Engi-
neering Research Council of Canada (NSERC) for financial
support of the project.
20. G.B. Watt, B.B. Hutchinson, and D.S. Klett. J. Am. Chem.
Soc. 89, 2007 (1967).
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