C.-F. Leung et al. / Inorganica Chimica Acta 362 (2009) 3576–3582
3577
2.2.5. [OsVI(N)(quin)2Br] (2c)
The complex was prepared by a method similar to that for 2a,
using [NBun4][OsVI(N)Br4] (104 mg, 0.136 mmol). Yield 54 mg
(62%). Anal. Calc. for C20H12N3O4BrOs: C, 38.21; H, 1.91; N, 6.69.
O
N
N
Picolinic acid
Quinaldic acid
(Hpic)
OH
Found C, 38.53; H, 2.04; N, 6.96%. UV–Vis (DMF) kmax, nm (e,
M
ꢀ1 cmꢀ1) = 327 (17 540). IR (KBr, cmꢀ1): 3068 (w), 1723 (vs),
1677 (vs), 1329 (w), 1311 (w), 1140 (w), 1078 (w, Os14N), 1045
(w, Os15N).
O
(Hquin)
2.2.6. [NBun4][OsVI(N)(Hdipic)Cl3] (3a)
OH
Pyridine-2,6-dicarboxylic acid (H2dipic; 23 mg, 0.136 mmol)
was added to an acetone solution (15 mL) of [NBun4][OsVI(N)Cl4]
(80 mg, 0.136 mmol). 2,6-Dimethylpyridine (0.5 mL) was then
added dropwise and the reaction mixture was stirred for 1 h. A
pink precipitate was formed, which was filtered and redissolved
in H2O (5 mL). Addition of tetrabutylammonium chloride
(37.80 mg, 0.136 mmol) produced in a pink solid which was
recrystallized from acetonitrile/ether. Yield 52 mg (53%). Anal. Calc.
for C24H40N3O4Cl3Os: C, 38.57; H, 5.58; N, 5.41. Found C, 38.38; H,
O
O
N
Pyridine-2,6-dicarboxylic acid (H2dipic)
OH
OH
Scheme 1. Pyridine-carboxylato ligands used.
5.56; N, 5.34%. UV–Vis (DMF) kmax, nm (e
, Mꢀ1 cmꢀ1) = 328 (850),
CH3CN. Kinetic studies were conducted with a Hi-Tech Scientific SF-
61 stopped-flow spectrophotometer in acetonitrile.
489 (120). IR (KBr, cmꢀ1): 2962 (s), 1675 (vs), 1315 (s), 1175 (w),
1086 (w), 1091 (w, Os14N), 1059 (w, Os15N).
2.2.7. [NBun4][OsVI(N)(Hdipic)Br3] (3b)
2.2. Synthesis of the complexes
The complex was prepared by a similar procedure for 3a using
[NBun4][OsVI(N)Br4] (104 mg, 0.136 mmol). Yield 73 mg (63%).
Crystals suitable for X-ray crystallography were grown from aceto-
nitrile/ether. Anal. Calc. for C24H40N3O4Br3Os: C, 32.38; H, 4.69; N,
4.93. Found C, 32.24; H, 4.57; N, 4.89%.
2.2.1. [OsVI(N)(pic)2Cl] (1a)
[NBun4][OsVI(N)Cl4] (80 mg, 0.136 mmol) was dissolved in
methanol (10 mL) and picolinic acid (32 mg, 0.272 mmol) was
added. The mixture was stirred and warmed to approx. 30 °C for
1 h. 2,6-Dimethylpyridine (0.5 mL) was then added dropwise and
the mixture was stirred at 30 °C for another 2 h. The yellow solid
formed was collected by filtration, washed with methanol and
air-dried. Yield 40 mg (60%). Anal. Calc. for C12H10N3O4ClOs: C,
29.66; H, 2.07; N, 8.65. Found C, 30.13; H, 1.80; N, 8.51%. UV-Vis
2.2.8. [OsIV(NPPh3)(pic)2Cl] (4)
[OsVI(N)(pic)2Cl] (80 mg, 0.165 mmol) was suspended in aceto-
nitrile (12 mL) and triphenylphosphine (43 mg, 0.165 mmol) was
added. The mixture was stirred for 1 h under argon. The yellow so-
lid gradually dissolved and an orange solid was formed, which was
filtered, washed with acetonitrile and air-dried. Yield 91 mg (74%).
Anal. Calc. for C35H25N3O4ClPOs: C, 48.28; H, 3.08; N, 5.63. Found C,
(DMF) kmax, nm (e
, Mꢀ1 cmꢀ1) = 418 (170). IR (KBr, cmꢀ1): 1708
(vs), 1670 (vs), 1322 (s), 1293 (w), 1082 (w, Os14N), 1048(w,
Os15N). 1H NMR (300 MHz, dmso-d6): d = 9.33 (d, 1H), 9.72 (d,
1H), 8.48 (m, 2H), 8.28 (d, 1H), 8.25 (t, 1H), 8.15 (t, 1H), 8.05 (t, 1H).
47.98; H, 3.20; N, 5.45%. UV–Vis (DMF) kmax, nm (e
, Mꢀ1 cmꢀ1): 373
(13 440). IR (KBr, cmꢀ1): 1684 (vs), 1324 (w), 1288 (w), 1108 (w,
NP), 1071 (w), 856 (w), 759 (w).
2.2.2. [OsVI(N)(pic)2Br] (1b)
The complex was synthesised as a yellow solid by a method
similar to that for 1a using [NBun4][OsVI(N)Br4] (104 mg,
0.136 mmol). Yield 45 mg (63%). Anal. Calc. for C12H12N3O4BrOs:
C, 27.16; H, 1.88; N, 7.92. Found C, 27.45; H, 1.65; N, 8.02%. UV-Vis
2.2.9. [OsIV(NPPh3)(quin)2Cl] (5a)
[OsVI(N)(quin)2Cl] (80 mg, 0.137 mmol) was suspended in ace-
tonitrile (12 mL) and triphenylphosphine (36 mg, 0.137 mmol)
was added. The mixture was stirred for 1 h under argon. The yel-
low solid gradually dissolved to give a dark brown solution, and
then a dark brown crystalline solid was formed, which was filtered,
washed with acetonitrile and then air-dried. Yield 84 mg (72%).
Anal. Calc. for C38H27N3O4ClOsP: C, 53.92; H, 3.19; N, 4.97. Found C,
53.80; H, 3.47; N, 5.21%. Recrystallization from acetonitrile/ether
affords dark brown single crystals suitable for X-ray crystallogra-
(DMF) kmax, nm (e
, Mꢀ1 cmꢀ1) = 311 (4130), 411 (570). IR (KBr,
cmꢀ1): 3079 (w), 1713 (vs), 1675 (vs), 1336 (s), 1314 (s), 1132
(w), 1082 (w, Os14N), 1047 (w, Os15N).
2.2.3. [OsVI(N)(quin)2Cl] (2a)
[NBun4][OsVI(N)Cl4] (80 mg, 0.136 mmol) was dissolved in
methanol (10 mL). Quinaldic acid (47 mg, 0.272 mmol) was added
and the mixture was stirred for 15 min. 2,6-Dimethylpyridine
(0.5 mL) was then added dropwise and the mixture was stirred
for another hour. The orange solid formed was collected by filtra-
tion and washed with methanol. Yield 55 mg (69%). Anal. Calc.
for C20H12N3O4ClOs: C, 41.12; H, 2.06; N, 7.20. Found C, 41.30; H,
phy. UV–Vis (DMF) kmax, nm (e
, Mꢀ1 cmꢀ1): 293 (14 850). IR (KBr,
cm-1): 3057 (w), 1677 (vs), 1320 (w), 1162 (w), 1108 (w, NP),
1064 (s).
2.2.10. [OsIV(NPPh3)(quin)2Br] (5b)
The complex was prepared by a similar procedure for 4a, using
2c. The product was recrystallized from acetonitrile. Yield 51 mg
(45%). Anal. Calc. for C38H27N3O4BrOsP: C, 51.24; H, 3.03; N, 4.72.
2.10; N, 7.09%. UV-Vis (DMF) kmax
,
nm
(e,
Mꢀ1 cmꢀ1) = 326
(11910), 450 (710). IR (KBr, cmꢀ1) = 3078 (w), 1714 (vs), 1679
(vs), 1328 (s), 1313 (s), 1148 (w), 1076 (w, Os14N), 1034 (w,
Os15N). 1H NMR (300 MHz, dmso-d6): d = 7.07 (m, 1H), 7.42 (m,
1H), 7.78 (m, 1H), 8.15 (m, 2H), 8.44 (m, 4H), 9.10 (m, 3H).
Found C, 51.13; H, 3.17; N, 4.94%. UV–Vis (CH2Cl2) kmax, nm (e,
M
ꢀ1 cmꢀ1): 243 (63 900), 300 (17 000), 638 (3080). IR(KBr,
cmꢀ1): 3057 (w), 1677 (vs), 1107 (w, NP).
2.2.4. [OsVI(N)(quin)2(OMe)] (2b)
Evaporation of the filtrate in the above reaction produced yel-
low crystals. Yield 11 mg (14%). Anal. Calc. for C21H16N3OsO5: C,
43.73; H, 2.08; N, 7.29. Found C, 43.53; H, 2.47; N, 7.51%.
2.2.11. trans-[PPN][OsIII(quin)2Cl2] (6)
[PPN](N3) (80 mg, 0.137 mmol) (PPN = Bis(triphenylphosphor-
anylidene)ammonium) was added to a suspension of [OsVI(N)