1558
v × 105, L/(mol s)
GEL’FMAN et al.
diethyl ether. The elemental analysis of product (b) was
carried out as described in [3].
For [Pt2(NH3)2(NO2)2Br2] anal. calcd. (%): Pt,
57.69; NO2, 13.61; Br, 23.67.
8
7
6
5
4
3
2
1
For [Pt(NH3)2Br2] anal. calcd. (%): Pt, 50.13; NO2,
0; Br, 41.13.
Found (%): Pt, 50.45; NO2, 0; Br, 41.40.
To react [Pden(NO2)2] or [Pt(mNO2)2] with KBr, the
complex (0.010 g) was dissolved in a 0.3 M aqueous
solution of NaNO3 (50 mL). Then, 10 mL of potassium
bromide solution (Ò = 1 × 10–2 mol/L) was added, and
the e.m.f. was measured over time. The bromide-ion
concentration did not change.
To plot the curves shown in Figs. 1 and 2, two sets
of kinetic experiments were carried out at 15°C. In one
set of experiments, the concentration of the complex
was fixed (Ò = 1 × 10–3 mo/L), and the KBr concentra-
tion was varied (Ò1 = 1 × 10–3 mol/L, Ò2 = 2 × 10–3 mol/L,
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
cKBr × 103, mol/L
Fig. 1. Substitution-reaction rate vs. KBr concentration at a
fixed starting concentration of the complex equal to Ò = 1 ×
–3
10 mol/L.
Ò3 = 3 × 10–3 mol/L). These experiments were carried
out as follows: [NO2(NH3)2PtNO2Pt(NH3)2NO2]NO3
(0.0329 g) was dissolved in a 0.3 M solution of NaNO3
(V1 = 40 mL, V2 = 35 mL, V3 = 30 mL), a KBr solution
(Ò = 1 × 10–2 mo/L; V1 = 10 mL, V2 = 15 mL, V3 = 20 mL)
was added, and the e.m.f. was measured over time.
v × 105, L/(mol s)
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
In the second set of experiments, the KBr concentra-
tion was fixed (Ò = 1 × 10–3 mol/L), and the concentra-
tion of the complex was varied (Ò1 = 0.5 × 10–3 mol/L,
Ò2 = 1 × 10–3 mol/L, Ò3 = 2 × 10–3 mol/L). These
experiments were carried out as follows.
[NO2(NH3)2PtNO2Pt(NH3)2NO2]NO3 (m1 = 0.01645 g,
m2 = 0.03290 g, m3 = 0.06582 g) was dissolved in a
0.3 M NaNO3 solution (40 mL), a KBr solution (10 mL;
Ò = 1 × 10–2 mol/L) was added, and the e.m.f. was mea-
sured over time.
0
0.5
1.0
1.5
2.0
2.5
The subsequent kinetic experiments were conducted
at the starting concentration of the complex equal to Ò =
1 × 10–3 mol/L and the KBr concentration equal to Ò =
2 × 10–3 mol/L for complexes with two nitrite bridges (for
complexes with one nitrite bridge, Ò = 1 × 10–3 mol/L). A
sample of the complex was dissolved in 40 mL (45 mL)
of an NaNO3 solution (c = 0.3 mol/L), then 10 mL
(5 mL) of a KBr solution (Ò = 1 × 10–2 mol/L) was
added, and the e.m.f. was measured over time.
The rate constants calculated from the equation for
a second-order reaction within one experiment remain
virtually constant.
ccompl × 103, mol/L
Fig. 2. Substitution-reaction rate vs. the concentration of the
complex at a fixed starting KBr concentration equal to
–3
Ò = 1 × 10 mol/L.
the thus-prepared precipitate was 21 × 10–6 Ω cm–1. The
reaction between [enPd(NO2)2Pden](NO3)2 and KBr
(1 : 2 mol/mol) was conducted in the same way. The
electrical conductivity of an aqueous solution of the
thus-prepared precipitate was 28 × 10–6 Ω–1 cm–1.
To react [(NH3)2Pt(NO2)2Pt(NO2)2] with KBr, to the
complex (0.1 g) in water (40 mL), KBr (0.391 g) was
added; the reagent ratio was 1 : 2 mol/mol. After 3 h, a
solution of [Pt(NH3)4]Cl2 was poured to the solution. A
yellow precipitate (a) was observed. This precipitate
was filtered, and the filtrate was concentrated to a min-
imum volume. The resulting yellow precipitate (b) was
The table displays the experimental data for the
reaction of complexes with potassium bromide at 15°C.
RESULTS AND DISCUSSION
In the consideration of the mechanism of formation
of binuclear complexes with nitrite bridges and their
filtered and rinsed with distilled water, ethanol, and reactions with various reagents, one should keep in
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 52 No. 10 2007