Tuning Reactivity of Platinum(II) Complexes

ligand was added to the [{cis-PtCl(NH3)2(DMF)]ClO4 solution slowly, in order to have
constantly excess of [{cis-PtCl(NH3)2(DMF)]ClO4 in the solution and stirred for 12 h and
after cooling at 5-10 °C for 1h, was filtered to remove any undissolved material. The
solvent was evaporated under vacuum. The residue was washed with diethyl ether, re-
dissolved in warm water (40-50 °C) and the water evaporated under vacuum to dryness.
The light yellow solid was washed with a minimal amount of ethanol followed by
concomitant amounts of diethyl ether and dried over potassium hydroxide (KOH) in a
desiccator. This process was repeated for 2,3pzn and 2,5pzn, using stoichiometric
amounts (0.279 mmol, 30.21 mg 2,3pzn; and 0.289 mmol, 31.22 mg 2,5pzn,
respectively) of the appropriate nitrogen ligand.
cis- [{PtCl(NH3)2}2–μ–2, 6 pzn]Cl2 (2,6pzn)
Literature procedure was used for the synthesis of the platinum complex, [{cis–
PtCl(NH3)2}2–μ–2,6pzn]Cl2 (2,6pzn). 25 A solution (5 mL) of 2,6pzn ligand (18.3 mg,
0.170 mmol) in water was added to a solution (10 mL) of cis–[Pt(NH3)2Cl2] (101.5 mg,
0.338 mmol) in water. The mixture was stirred for 3 days at 40 °C in the dark, filtered to
remove any unreacted material and concentrated to 1-2 mL under vacuum. The
compound formed, [{cis–Pt(NH3)2Cl}2–µ–2,6–pzn]Cl2, was filtered off, washed with a
small amount of ethanol, diethyl ether and dried under vacuum.
Their purity was confirmed by micro-elemental analysis, infrared (IR), 1 H and 195 Pt
NMR. The IR spectra of all the complexes exhibited common characteristic peaks in the
range 326-400 cm -1 (weak) for Pt–Cl and 1090-1100 cm -1 (broad, strong) for Cl–O
(perchlorate counter ion) vibration stretches, respectively. The results obtained from
the analysis of the complexes are given below.
(pzn) Yield: 382.8 mg (45.5%). 1 H NMR (500 MHz, D2O), δ /ppm: 8.99, s (4H). 195 Pt
NMR (107 MHz, D2O) δ/ppm: -2302.2. IR (KBr, 4000-300 cm -1): 3305, 3224, 3107 (N–H
stretch); 1090-1100 (perchlorate counter ion); 340 (Pt–Cl stretch). Anal. Calc. for
C4H16N6Cl4O8Pt2: H, 2.00; C, 5.94; N, 10.40; Found H, 2.23; C, 5.50; N, 9.90 %.
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