V.T. Yilmaz et al. / Journal of Organometallic Chemistry 694 (2009) 3306–3311
3307
ꢁ
1
sample size of 5–10 mg and platinum crucibles. Excitation and
emission spectra of the ligands and their solid complexes were re-
corded at room temperature with a Varian Cary Eclipse spectro-
photometer equipped with a Xe pulse lamp of 75 kW, using
excitation and emission slits of 20 nm.
3461 cm for 2 are assigned to the
water molecules. The
as a distinct band at 3191 cm and 3184 cm for 1 and 2, respec-
m
(OH) vibrations of the lattice
m
(NH) stretching of the barb ligands appears
ꢁ1
ꢁ1
ꢁ1
tively. The multiple weak bands in the range 2830–3095 cm are
attributed to the C–H stretching vibrations. The three sharp bands
ꢁ1
in the frequency range 1630–1720 cm characterize the carbonyl
group vibrations of the barb ligands. The barb ligand exists in
triketo form and the carbonyl groups do not participate in coordi-
nation in these complexes. Compared to that of Na(barb), the
apparent red-shifts may, therefore, be associated with strong
hydrogen bonding associated with the carbonyl groups. The four
of five intense bands between 1605 and 1315 cm corresponds
to both in-plane vibrations of the C–C bonds, and C–H deformation
vibrations, while the C–N stretchings occur as strong bands
2.2. Synthesis of the silver(I) complexes
Na(barb) (5,5-diethylbarbituric acid sodium salt) (0.21 g,
1
mmol) dissolved in water (10 ml) was added to a solution of
AgNO (0.17 g, 21 mmol) in water (10 ml) with stirring at room
3
ꢁ1
temperature. The solution immediately became milky. The addi-
tion of pyridine-2-ylmethanol (pym) (0.10 ml) together with a
mixture of 2-propanol (PrOH) and acetonitrile (MeCN) (1:1)
ꢁ1
(
10 mL) to the milky suspension resulted in a clear solution. The fi-
nal solution was allowed to stand in darkness at room temperature
and colorless prisms of [Ag(barb)(pym)]ꢀH O (1) were obtained
after 3 days. Yield 77%. M.p. 141 °C (decomp). Anal. Calc. for
centered at ca. 1258 cm .
2
3.2. Description of the crystal structures
C
1
2
1
7
14
H
20AgN
3
O
5
: C, 40.2; H, 4.8; N, 10.1. Found: C, 40.4; H, 4.5; N,
The molecular structures of 1 and 2 are shown in Figs. 1 and 2,
respectively. Selected bond lengths and angles are listed in Table 3
together with the hydrogen bond parameters. Complexes 1 and 2
ꢁ1
0.3%. IR (cm ): 3395sb, 3191mb, 3085w, 2974w, 2929vw,
868w, 1716s, 1675vs, 1638vs, 1601vs, 1458w, 1422vs, 1364vs,
336sh, 1315vs, 1258s, 1164vw, 1103vw, 1062w, 1005w, 833w,
64s, 698w, 645vw, 613vw, 543m, 474w, 449w.
Table 1
[
Ag(barb)(dmpy)]ꢀ1.5H
using dmpy instead of pym. Yield 65%. M.p. 100 °C (decomp). Anal.
Calc. for C15 23AgN : C, 39.4; H, 5.1; N, 9.2. Found: C, 39.7 H,
.5; N, 9.4%. IR (cm ): 3470sb, 3184sb, 3086w, 3028w, 2969w,
2
O (2) was synthesized in a similar way
Crystallographic data and structure refinement for 1 and 2.
1
2
H
3 6 5
O .
ꢁ1
5
2
1
9
Formula
C
14
H
20AgN
3
O
5
15 3 5
C H20AgN O
Molecular weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
Unit cell dimensions
a (Å)
418.20
150(2)
0.71073
Orthorhombic
Pbca
430.21
150(2)
936vw, 2875w, 1712s, 1676vs, 1634vs, 1605vs, 1553s, 1460w,
423vs, 1369vs, 1319vs, 1257s, 1166vw, 1140vw, 1070w, 1023m,
48w, 844w, 791m, 764m, 730vw, 695w, 542m, 474w, 444w.
0.71073
Triclinic
ꢀ
P1
2.3. X-ray crystallography
7.2174(2)
13.6482(6)
32.9402(10)
90
90
90
3244.8(2)
8
1.712
6.8619(3)
b (Å)
c (Å)
11.4893(5)
12.3456(5)
100.611(3)
97.995(4)
96.317(4)
938.12(7)
2
The data collection was performed at 150 K on a Stoe-IPDS-2
diffractometer equipped with a graphite monochromated Mo K
radiation (k = 0.71073 Å). The data reduction and numerical
absorption correction were performed using the X-RED program
a
a
(°)
b (°)
(°)
c
3
Volume (Å )
[
[
[
16]. The structures were solved by direct methods using SHELXS97
17] and refined on F by a full-matrix least-squares using SHELXL97
17]. All non-hydrogen atoms were easily found from the differ-
Z
2
3
Calculated density (g/cm )
1.523
1.101
ꢁ
1
l
(mm
)
1.271
F(0 0 0)
Crystal size (mm )
h range (°)
1696
436
ence Fourier map and refined anisotropically. Hydrogen atoms
bonded to C and N atoms were refined using a riding model, with
C–H = 0.96–0.97 Å and N–H = 0.86–0.91 Å. The constraint Uiso(H) =
3
0.58 ꢂ 0.41 ꢂ 0.16
2.47–26.74
ꢁ8/9; ꢁ17/16; ꢁ38/
41
0.55 ꢂ 0.35 ꢂ 0.07
1.82–26.50
ꢁ8/8; ꢁ14/14; ꢁ15/
15
Index ranges (h, k, l)
1
.2Ueq(C and N) or 1.5Ueq(methyl C) was applied. The H atoms of
water molecules in 1 were refined freely. The unit cell of 2 has
an accessible solvent volume of 92.5 ÅA , which are occupied by se-
Reflections collected
Independent reflections [R(int)
13 830
3425 [0.0328]
3006
Numerical
3425/217
1.054
14 445
3889 [0.0489]
3662
Numerical
3889/217
1.022
0
3
]
Reflections observed (>2
Absorption correction
Data/parameters
r)
verely disordered water molecules. Therefore, the water molecules
were eliminated from the refinement of the structure by means of
the SQUEEZE subroutine of PLATON and the hkl intensities were
modified accordingly [18]. Details of crystal data, data collection,
structure solution and refinement are given in Table 1.
Goodness-of-fit (GOF) on F2
Final R indices [I > 2
r
(I)]
R
1
= 0.0260,
wR = 0.0691
0.443 and ꢁ0.838
R
1
= 0.0246,
wR = 0.0624
0.442 and ꢁ0.520
2
2
Largest difference peak and hole
ꢁ
3
(
e Å )
3
. Results and discussion
Table 2
Selected FTIR spectral data for 1 and 2.
3.1. Synthesis and IR characterization
a
Assignment
1
2
The direct reactions between stoichiometric amounts of AgNO
3
m(OH)
m(NH)
m(CH)
m(CO)
m(CC)
3395sb
3191mb
3461sb
3184sb
and Na(barb) were carried out in the presence of pym or dmpy in a
PrOH/MeCN solution (1/1) at room temperature and afforded the
complexes 1 and 2 in good yields, as colorless crystalline solids,
which were fully characterized (see Section 2). Both compounds
are stable in solid state and soluble in the warm EtOH/MeCN mix-
ture (1:1).
3085w, 2974w, 2929vw, 2868w 3085w, 2970m, 2929vw, 2868w
1716s, 1675vs, 1638vs
1601vs
1422vs, 1364vs, 1315vs
1258s
1715s, 1675vs, 1638vs
1605vs
1423vs, 1369vs, 1319vs
1257vs
d(CH)
m(CN)
a
ꢁ1
Selected FTIR spectral data for 1 and 2 are given in Table 2. The
Frequencies in cm
.
b = broad; m = medium; w = weak; vw = very weak;
ꢁ1
vs = very strong; s = strong; sh = shoulder.
strong and broad absorption bands at 3395 cm
for 1 and