Organometallics
Article
[Pd(μ-AcO)(H−C^N-SO3Na)]2 (1). Yield: 0.98 g, 95%. Anal. Found:
C, 40.6; H, 2.9; N, 3.1; S, 7.1. Calcd for C30H24N2Na2O10Pd2S2: C,
40.2; H, 2.7; N, 3.0; S, 7.0. IR (cm−1): 1586s, 1568vs, 1549s, 1197s
(SO3), 1137m (SO3), 1045m (SO3), 843s, 652s, 589m. ESI-MS
(negative mode): calcd for C14H10NO5SPd [PdL1(formate)] − Na
m/z 409.9320 (found 409.9319); calcd for C27H19N2O8S2Pd2
[Pd2L12(formate)] − 2Na m/z 776.8667 (found 776.8667). 1H
NMR (400 MHz, CD3OD): δ (ppm) 7.96 (s, 1H; NCH), 7.56 (d,
2H, Hm-sulf; J = 8.4 Hz), 7.34 (d, 1H; Ho-ald, J = 6.8 Hz), 7.07 (m,
1H; Hp-ald), 6.93 (m, 1H; Hm, ald), 6.80 (d, 2H; Ho-sulf, J = 8.4
Hz), 6.40 (d, 1H; Hm-ald, J = 8.0 Hz), 1.81 (s, 3H; AcO). 13C{1H}
NMR (300 MHz, CD3OD): δ (ppm) 181.8 (CO, AcO), 176.7
(NCH), 155.9, 150.3, 147.3, 145.1, 133.0, 132.4, 129.9, 127.2,
(SO3), 1100s (SO3), 1030m (SO3); ν(PPh3) 528, 512. ESI-MS
(positive mode): calcd for C32H27NO4PPdS [PdL2PPh3 + 1] − Na
1
m/z 658.0445 (found 658.0446). H NMR (300 MHz, CD3OD): δ
(ppm) 8.09 (d, 1H, NCH, J = 6.0 Hz), 7.66 (m, 6H, 4H PPh3 + 2H
Hm-sulf), 7.40 (m, 3H, PPh3), 7.30 (m, 7H, 6H, PPh3 + 1H, Ho-ald),
7.10 (dd, 2H, Ho-sulf, J1 = 2.0 Hz, J2 = 2.0 Hz), 6.34 (dd, 1H, Hm-
ald; J1 = 2,4 Hz, J2 = 2,4 Hz), 5.88 (dd, br; 1H, Hm-ald; J1 = 2,4 Hz
J2 = 2,4 Hz), 3.63 (s, 3H, OCH3), 0.88 (s, 3H, AcO). 31P{1H} NMR
(300 MHz, CD3OD): δ (ppm): 42.09. SH O,20 °C = 2.73 mg/mL.
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2
[Pd(Cl−C^N-SO3Na)(AcO)(PPh3)] (6). Yield: 0.069 g, 63%). Anal.
Found: C, 53.5; H, 3.6; N, 2.0; S, 4.5.Calc. for C33H26ClNNaO5PPdS:
C, 53.2; H, 3.5; N, 1.9; S, 4.3%. IR (cm−1):ν(C = O) 1572s br,
1540m, 1194s (SO3), 1127m (SO3), 1037m (SO3); ν(PPh3) 543,
509. ESI-MS (positive mode): calc. for C31H24ClNO3PPdS
125.7, 124.0, 24.2 (CH3, AcO). SH O,20 °C = 10.47 mg/mL.
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2
1
[PdL3PPh3 + 1] - Na m/z 663.9937 (found 663.9927). H NMR
[Pd(μ-AcO)(MeO-C^N-SO3Na)]2 (2). Yield: 0.86 g, 86%. Anal.
Found: C, 40.6; H, 3.1; N, 3.0; S, 6.9. Calcd for
C32H28N2Na2O12Pd2S2: C, 40.2; H, 2.9; N, 2.9; S, 6.7. IR (cm−1):
1587m, 1562s, 1542m, 1273m, 1200s (SO3), 1133m (SO3), 1045m
(SO3), 847m, 808m, 640s, 593m. ESI-MS (negative mode): calcd for
C15H12NO6PdS [PdL2(formate)] − Na m/z 439.9426 (found
439.9426), calcd for C29H23N2O101Pd2S2 [Pd2L22(formate)] − 2Na
m/z 836.8879 (found 836.8877). H NMR (300 MHz, CD3OD): δ
(ppm): 7.73 (s, 1H; NCH), 7.58 (d, 2H; Hm-sulf, J = 8.4 Hz), 7.28
(d, 1H; Ho-ald, J = 8.4 Hz), 6.71 (d, 2H; Ho-sulf, J = 8.4 Hz), 6.61
(d, 1H; Hm-ald, J = 8.4 Hz), 5.89 (s, 1H; Hm-ald), 3.55 (s, 3H;
OCH3), 1.80 (s, 3H; AcO). 13C{1H} NMR (300 MHz, CD3OD): δ
(ppm) 181.7 (CO, AcO), 175.0 (NCH), 162.3, 159.3, 150.2,
144.9, 139.9, 131.4, 126.9, 123.9, 117.2, 112.5, 56.0 (OCH3), 24.2
(300 MHz, CD3OD): δ (ppm) 8.37 (d, 1H, NCH, J = 6.1 Hz),
7.67 (m, 8H, 6H PPh3 + 2H Hm-sulf), 7.36 (m, 12H, 9H, PPh3 + 1H,
Ho-ald +2H, Ho-sulf), 6.88 (dd, 1H, Hm-ald, J1 = 2,1 Hz J2 = 1,8
Hz), 6.29 (dd, 1H, Ho-ald, J1 = 1,8 Hz J2 = 1,8 Hz), 0.87 (s, 3H,
CH3). 31P{1H} NMR (300 MHz, CD3OD): δ (ppm) 40.07. S
̅
H2O,20 °C
= 6.23 mg/mL.
Data Related to Nucleosides. General Procedure for Suzuki−
Miyaura Cross-Coupling of 5-Iodo-2′-deoxyuridine with Arylbor-
onic Acids. A solution of precatalyst 3 (0.5 mol %) in degassed H2O
(4 mL) was stirred for 5 min at ambient temperature under N2. Then,
́
5-iodo-2-deoxyuridine (177 mg, 0.5 mmol) was added and the
solution was stirred for 5 min at 60 °C. Thereafter, 2-
benzofuranylboronic acid (120 mg, 0.75 mmol) was added along
with Et3N (1.0 mmol). The resulting solution was then stirred at 60
°C for 3.0 h. After the completion of the reaction the solvent was
removed under vacuum and the resultant residue obtained was
purified using column chromatography in a CH2Cl2/MeOH solvent
system (96/4) to afford the desired product as a white solid in 89%
yield (153 mg).
(CH3, AcO). SH O,20 °C = 12.73 mg/mL.
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2
[Pd(μ-AcO)(Cl−C^N-SO3Na)]2 (3). Yield: 1.06 g, 97%. Anal.
Found: C, 37.6; H, 2.6; N, 3.2; S, 6.9. Calcd for
C30H22Cl2N2Na2O10Pd2S2: C, 37.3; H, 2.3; N, 2.9; S, 6.6. IR
(cm−1): 1582m, 1557s, 1536m, 1201s (SO3), 1137s (SO3), 1093m,
1049m (SO3), 840m, 814m, 751m, 664m, 623s 589m. ESI-MS
(negative mode): calcd for C14H9ClNO5SPd [PdL3(formate)] − Na
m/z 445.8921 (found 445.8931); calcd for C27H17Cl2N2O8S2Pd2
[Pd2L32(formate)] − Na m/z 844.7875 (found 844.7870). 1H
NMR (300 MHz, CD3OD): δ (ppm) 7.92 (s, 1H; NCH), 7.78 (d,
2H; Hm-sulf, J = 8.4 Hz), 7.28 (d, 1H; Ho-ald, J = 8.1 Hz), 7.13 (d,
1H; Hm-ald, J = 8.1 Hz), 6.90 (d, 2H; Ho-sulf, J = 8.4 Hz), 6.48 (s,
1H; Hm-ald), 1.69 (s, 3H; AcO). 13C{1H} NMR (300 MHz,
CD3OD): δ (ppm) 182.6 (CO), 176.0 (NCH), 157.3, 149.5,
145.9, 137.5, 132.9, 130.9, 128.3, 127.5, 126.1, 124.1, 24.1 (CH3,
General Procedure for Suzuki−Miyaura Cross-Coupling of 5-
Iodo-2′-deoxycytidine with Arylboronic Acids. A solution of
precatalyst 3 (0.5 mol %) in degassed H2O (4.0 mL) was stirred
́
for 5 min at ambient temperature under N2. Then, 5-iodo-2-
deoxycytidine (176 mg, 0.5 mmol) was added and the solution was
stirred for 5 min at 60 °C. Thereafter, 3-thiopheneboronic acid (0.75
mmol) was added along with Et3N (1.0 mmol). The resulting solution
was then stirred at 60 °C for 24.0 h. After the completion of the
reaction the solvent was removed under vacuum and the resultant
residue obtained was purified using column chromatography in a
CH2Cl2/MeOH solvent system (95/5) to afford the desired product
as a white solid in 72% yield (110 mg).
AcO). SH O,20 °C = 20.57 mg/mL.
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2
Preparation of the Complexes [Pd(R-C^N-SO3Na)(AcO)-
(PPh3)] (R = H (4), MeO (5), Cl (6)). The new complexes were
obtained by treating 0.07 g of the appropriate precursor [Pd(μ-
AcO)(R-C^N-SO3Na)]2 (R = H (1), OMe (2), Cl (3)) dissolved in
MeOH (10 mL) with the stoichiometric amount of triphenylphos-
phine (molar ratio 1:2) previously dissolved in 5 mL of MeOH. The
resulting solution was stirred for 30 min and then filtered through a
short Celite column and concentrated until ca. one-fifth of the initial
volume. Slow addition of diethyl ether completed the precipitation of
the title complexes, which were filtered off, washed with ether, and air-
dried.
General Procedure for Mercury (Hg) Poisoning Study. A solution
of precatalyst 3 (0.5 mol %) in degassed H2O (4.0 mL) was stirred for
́
5 min at ambient temperature under N2. Then, 5-iodo-2-deoxyuridine
(177 mg, 0.5 mmol) was added and the solution was stirred for 5 min
at 60 °C. Thereafter, 2-benzofuranylboronic acid (0.75 mmol) was
added along with Et3N (1.0 mmol). Mercury (Hg) (0.15 mmol, 30
mg) was then added (at the start of the reaction), and the reaction
mixture was stirred at 60 °C for 3 h. On completion of the stipulated
time, a TLC analysis of the reaction mixture revealed no progress in
the reaction, thus suggesting complete inhibition of the catalytic
reaction.
[Pd(C^N-SO3Na)(AcO)(PPh3)] (4). Yield: 0.055 g, 50%. Anal.
Found: C, 56.0; H, 4.0; N, 2.1; S, 4.6. Calcd for C33H27NNaO5PPdS:
C, 55.8; H, 3.8; N, 2.0; S, 4.5. IR (cm−1): ν(CO) 1585s br, 1197s
(SO3), 1129s (SO3), 1038m (SO3); ν(PPh3) 537, 518. ESI-MS
(positive mode): calcd for C31H25NO3PPdS [PdL1PPh3 + 1] − Na
General Procedure for Carbon Disulfide Poisoning Study. A
solution of precatalyst 3 (0.5 mol %) in degassed H2O (4.0 mL) was
́
stirred for 5 min at ambient temperature under N2. Then, 5-iodo-2-
deoxyuridine (177 mg, 0.5 mmol) was added and the solution was
stirred for 5 min at 60 °C. Thereafter, 2-benzofuranylboronic acid
(0.75 mmol) was added along with Et3N (1.0 mmol). Carbon
disulfide (CS2) (0.25 mL, 5 mmol) was then added (at the start of the
reaction), and the reaction mixture was stirred at 60 °C for 3 h. On
completion of the stipulated time, a TLC analysis of the reaction
mixture revealed no progress in the reaction, thus suggesting complete
inhibition of the catalytic reaction.
1
m/z 628.0338 (found 628.0323). H NMR (300 MHz, CD3OD): δ
(ppm) 8.34 (d, 1H, NCH, J = 6.9 Hz), 7.72 (d, 2H, Hm-sulf, J =
8,4 Hz), 7.65 (m, 6H, 5H, PPh3 + 1H, Ho-ald), 7.52 (m, 1H, Hp-ald),
7.39 (m, 5H, 4H, PPh3 + 1H, Ho-ald), 7.29 (m, 8H, 6H, PPh3 + 2H,
Ho-sulf), 6.86 (m, 1H, Hm-ald), 0.99·s, 3H, AcO).31P{1H} NMR
(300 MHz, CD3OD): δ(ppm): 42.40. SH O,20 °C = 3.13 mg/mL.
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2
[Pd(MeO-C^N-SO3Na)(AcO)(PPh3)] (5). Yield: 0.084 g, 77%. Anal.
Found: C, 55.5; H, 4.1; N, 2.0; S, 4.4. Calcd for C34H29NNaO6PPdS:
C, 55.2; H, 3.9; N, 1.9; S, 4.3. IR (cm−1): ν(CO) 1582s br, 1199s
General Procedure for Tetra-n-butylammonium Bromide (TBAB)
Study. A solution of precatalyst 3 (0.5 mol %) in degassed H2O (4.0
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Organometallics XXXX, XXX, XXX−XXX