Synthesis and structural characterization of the adducts of silver(I) perchlorate and nitrate with triphenylphosphine and bis(pyrazolyl)methane ligands of 1:1:1 stoichiometry

Article abstract of DOI:10.1016/j.ica.2006.11.004

Six new adducts of the form AgX:PPh₃:H₂C(pz^x)₂ (1:1:1) (H₂C(pz^x)₂ = H₂C(pz)₂ = bis(pyrazolyl)methane or H₂C(pz^Me2)₂ = bis(3,5-dimethylpyrazolyl)methane; X = ClO₄, NO₃, SO₃CF₃) have been synthesized and characterized by analytical, spectroscopic (IR, far-IR, ¹H and ³¹P NMR) and two of them also by single crystal X-ray diffraction studies for comparison with counterpart adducts with 2,2′-bipyridyl ('bpy') derivatives reported in a previous paper, the bpy-derived ligands forming five-membered chelate rings, while the present H₂C(pz^x)₂ should, potentially, form six-membered rings. Such is the case, the two adducts exhibiting quasi-planar N₂AgP coordination environments, perturbed by the approach of the oxyanion, unidentate in the case of the perchlorate but, in the case of the nitrate, an interesting disordered aggregate of differing unidentate modes.

Full text of DOI:10.1016/j.ica.2006.11.004

Inorganica Chimica Acta 360 (2007) 2265–2270
www.elsevier.com/locate/ica
Synthesis and structural characterization of the adducts of
silver(I) perchlorate and nitrate with triphenylphosphine
and bis(pyrazolyl)methane ligands of 1:1:1 stoichiometry
a
a,
a,
*
Adele Cerquetella , Effendy b,c, Claudio Pettinari *, Riccardo Pettinari
,
b
b
Brian W. Skelton , Allan H. White
a
`
Dipartimento di Scienze Chimiche, Universita degli Studi di Camerino, via S. Agostino 1, 62032 Camerino MC, Italy
Chemistry M313, School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, Crawley, WA 6009, Australia
b
c
Jurusan Pendidikan Kimia, FMIPA Universitas Negeri Malang, Jalan Surabaya 6, Malang 65145, Indonesia
Received 7 October 2006; accepted 5 November 2006
Available online 11 November 2006
Abstract
Six new adducts of the form AgX:PPh3:H2C(pzx)2 (1:1:1) (H2C(pzx)2 = H2C(pz)2 = bis(pyrazolyl)methane or H2C(pzMe2)2 = bis(3,5-
dimethylpyrazolyl)methane; X = ClO4, NO3, SO3CF3) have been synthesized and characterized by analytical, spectroscopic (IR, far-IR,
31
1H and P NMR) and two of them also by single crystal X-ray diffraction studies for comparison with counterpart adducts with 2,20-
bipyridyl (‘bpy’) derivatives reported in a previous paper, the bpy-derived ligands forming five-membered chelate rings, while the present
H2C(pzx)2 should, potentially, form six-membered rings. Such is the case, the two adducts exhibiting quasi-planar N2AgP coordination
environments, perturbed by the approach of the oxyanion, unidentate in the case of the perchlorate but, in the case of the nitrate, an
interesting disordered aggregate of differing unidentate modes.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Silver(I) complexes; Phosphines; N-donor ligands; Pyrazolylmethanes; X-ray; NMR
1. Introduction
containing bis(pyrazol-1-yl)methanes (bidentate N-donor
ligands firstly reported by Trofimenko [4]) has been
recently described: closed-shell [AgL2]+ [5–8] and [CuL2]+
[9,10] (L = RR0C(pz)2, R,R0 = H, Me, Ph, CH2Ph, py,
Fc) species, [Cu2(l-X)2L2] [11,12] (X = halogen or pseudo-
halogen), [CuL(NCMe)2]+ and [CuL(NCMe)]+ [13], L
being bidentate chelate. A dinuclear [Ag2(l-L)2](OTf)2
(OTf = trifluoromethanesulfonate) in which the ligand
bridges both silver centres, has been also described [14].
Our group has reported the formation of adducts between
copper salts and bidentate ligands [H2C(pzx)2] also in the
presence of ancillary ligands such as mono- or bidentate
P-donors [15,16], and, in the above context, we were
interested to explore the nature of any counterpart silver
adducts to the above, using for the purpose H2C(pz)2 =
In previous papers [1,2], we have described the synthesis
and structural and spectroscopic characterization of a
diverse array of adducts of 1:1:1 stoichiometry formed
between AgX (X = perchlorate or nitrate (also carboxylate
[3], not relevant here)), tertiary phosphine, and N,N0-
bidentate bases derivative of 2,20-bipyridyl (‘bpy’), the lat-
ter capable of forming five-membered chelate rings; a num-
ber of adducts of ‘dpa’ (= bis(2-pyridyl)amine), potentially
and actually capable of forming six-membered rings were
also described. A number of group 11 metal complexes
*
Corresponding authors. Fax: +39 0737 637345 (C. Pettinari); +39 0737
402338 (R. Pettinari).
E-mail addresses: claudio.pettinari@unicam.it (C. Pettinari), riccardo.
pettinari@unicam.it (R. Pettinari).
bis(pyrazolyl)methane
and
H2C(pzMe2)2 = bis(3,5-
dimethyl)pyrazolylmethane, potentially capable of forming
0020-1693/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2006.11.004

2266
A. Cerquetella et al. / Inorganica Chimica Acta 360 (2007) 2265–2270
six-membered chelate rings as demonstrated elsewhere [8].
We record the results of this work hereunder.
293 K): d 15.0 (s, br); 31P{1H} NMR (CDCl3, 223 K):
1
15.4 (d, br, J(31P,Ag) = 680 Hz).
2. Experimental
2.1.3. AgSO3CF3:PPh3:H2C(pz)2 (1:1:1) (3)
Compound 3 was prepared following a procedure simi-
lar to that reported for 1 by using AgSO3CF3 (0.256 g,
1.0 mmol), PPh3 (0.262 g, 0.1 mmol) and H2C(pz)2
(0.148 g, 0.1 mmol); m.p. 168–171 ꢁC. Anal. Calc. for
C26H23AgF3N4O3PS: C, 46.79; H 3.47; N, 8.39. Found:
C, 47.21; H, 3.67; N, 8.12%. IR (nujol, cmꢀ1): 3137
All syntheses and handling were carried out in the
air. All chemicals were purchased from Aldrich and
Lancaster and used without further purification. Elemen-
tal analyses (C,H,N) were performed in-house with a
Fisons Instruments 1108 CHNS-O Elemental Analyser.
IR spectra were recorded from 4000 to 100 cmꢀ1 with
a Perkin–Elmer System 2000 FT-IR instrument. 1H,
13C and 31P NMR spectra were recorded on a Mercury
Plus Varian 400 NMR spectrometer (400 MHz for 1H,
100 MHz for 13C, and 162.1 MHz for 31P) or on a Var-
ian VXR-300 (300 MHz for 1H, 75 MHz for 13C, and
121.4 MHz for 31P). H and C chemical shifts are
reported in ppm versus SiMe4, P chemical shifts in
ppm versus H3PO4 85%.
. . .
(CH), 1573w, 1557w, 1537w, 1515m, 1504w m(C C,
•
. . .
C
N), 1281s, 1245m, 1224m, 1211m, 1165m, 1140m
•
1093m (O3SCF3), 640s, 571m, 520s, 496s, 437m, 401m,
365m . H NMR (CDCl3): d, 6.31 (t, 2H, H4pz), 6.70 (s,
1
2H, CH2), 7.38 (d, 2H, H5pz), 7.45 (m, 15H, CHPh), 8.35
(d, 2H, H3pz). 31P{1H} NMR (CDCl3, 293 K): d 16.1 (d,
1
br, J(31P,Ag) = 727 Hz).
2.1.4. AgClO4:PPh3:H2C(pzMe2)2 (1:1:1). MeCN (4)
To an MeCN solution containing 0.207 g (1.0 mmol) of
AgClO4 and 0.262 g (1.0 mmol) of triphenylphosphine,
0.408 g (2.0 mmol) of H2C(pzMe2)2 was added. The reac-
tion was stirred under reflux for 24 h in a round-bottomed
flask protected from the light. A colorless precipitate
formed which was filtered off, washed with MeCN and
identified as compound 4. Upon slow evaporation at room
temperature of the mother liquor, small crystals were
formed that were identified as compound 4; m.p. 158–
160 ꢁC. Anal. Calc. for C31H34AgClN5O4P: C, 52.08; H,
4.79; N, 9.80. Found: C, 52.40; H, 4.72; N, 9.71%. IR
2.1. Syntheses
Safety note. Perchlorate salts of metal complexes with
organic ligands are potentially explosive! Only small
amounts of materials should be prepared, and these should
be handled with great caution.
2.1.1. AgClO4:PPh3:H2C(pz)2 (1:1:1) (1)
To a MeCN solution containing 0.207 g (1.0 mmol) of
AgClO4 and 0.262 g (1.0 mmol) of triphenylphosphine,
0.148 g (1.0 mmol) of H2C(pz)2 was added. The reaction
was stirred under reflux for 14 h in a round-bottomed flask
protected from the light. The solution was then evaporated
and the residue washed with diethyl ether. A precipitate
formed that has been identified as compound 1 (80% yield);
m.p. 148–150 ꢁC. Anal. Calc. for C25H23N4AgClO4P: C,
48.61; H, 3.75; N, 9.07. Found: C, 49.01; H, 3.64; N,
9.01%. IR (nujol, cmꢀ1): 3113w (CH) 1962w br, 1888w
(nujol, cmꢀ1): 3132w (CH), 2250w (C–N), 1990w br,
. . .
1901w br, 1820w br, 1780w br (ClO4), 1556s m(C C,
•
. . .
C
N), 1074 sbr, 1031br m(ClO4), 625s br, 500s, 470w,
•
1
429w. H NMR (CDCl3): d, 1.98 (s, 6H, 5-CH3pz), 2.00
(s, 3H, CH3CN), 2.48 (s, 6H, 3-CH3pz), 5.89 (s, 2H,
H4pz), 6.31 (s, 2H, CH2), 7.47 (m, 15H, CHPh). 31P{1H}
NMR (CDCl3, 294 K): 15.9 s br. 31P{1H} NMR (CDCl3,
223 K): 15.8 (d br, J(31P,Ag) = 680 Hz).
1
. . .
br, 1822w br, 1770w br (ClO4), 1584w, 1514s (C C,
•
C
N), 1082 sbr 620 br, (ClO4), 522s, 492s, 439m, 401m.
2.1.5. AgNO3:PPh3:H2C(pzMe2)2 (1:1:1) (5)
. . .
•
1H NMR (CDCl3): d, 6.30 (br, 2H, H4pz), 6.57 (br, 2H,
CH2), 7.27–7.43 (m, 17H, CHPh + H5pz), 8.20 (br, 2H,
Compound 5 was prepared following a procedure simi-
lar to that reported for 4 by using AgNO3 (0.169 g,
H3pz). 31P{1H} NMR (CDCl3, 293 K): d 15.5 (d, br, J
1.0 mmol), PPh3 (0.262 g, 1.0 mmol) and H2C(pzMe2
)
1
2
(31P,Ag) = 710 Hz).
(0.408 g, 2.0 mmol); m.p. 197–198 ꢁC. Anal. Calc. for
C29H31AgN5O3P: C, 54.73; H, 4.91; N, 11.00. Found: C,
54.92; H, 4.78; N, 11.2%. IR (nujol, cmꢀ1): 3156w (CH)
1887w, 1830w, 1745w, 1678w, 1587w (NO3) 1557s, 1521s,
2.1.2. AgNO3:PPh3:H2C(pz)2 (1:1:1) (2)
Compound 2 was prepared following a procedure simi-
lar to that reported for 1 by using AgNO3 (0.169 g,
1.0 mmol), PPh3 (0.262 g, 1.0 mmol) and H2C(pz)2
(0.148 g, 0.1 mmol); m.p. 138–140 ꢁC. Anal. Calc. for
C25H23N5AgO3P: C, 51.74; H, 3.99; N, 12.07. Found: C,
51.92; H, 4.03; N, 11.65%. IR (nujol, cmꢀ1): 3102w (CH),
1891w, 1826w, 1766, 1741br (NO3), 1584w, 1572w, 1517s
. . .
. . .
(C C, C N), 1340br, 1300br, 1260br (NO3), 521s,
•
•
503m, 489s, 470w, 441w, 426w, 345w, 324w, 279w, 253w.
1H NMR (CDCl3): d, 1.95 (s, 6H, 5-CH3pz), 2.43 (s, 6H,
3-CH3pz), 5.83 (s, 2H, H4pz), 6.33 (s, 2H, CH2), 7.47 (m,
15H, CHPh). 31P{1H} NMR (CDCl3, 293 K): 15.6 (d, br,
1J(31P,Ag) = 574 Hz).
. . .
. . .
(C C, C N), 1360brm 1309s br, 1284m (NO3) 612w,
•
•
1
520m, 493m, 442w, 409w. H NMR (CDCl3): d, 6.25 (t,
2H, H4pz), 6.49 (s, 2H, CH2), 7.44 (m, 15H, CHPh), 7.48
(s, 2H, H5pz), 7.98 (d, 2H, H3pz). 31P{1H} NMR (CDCl3,
2.1.6. AgO3SCF3:PPh3:H2C(pzMe2)2 (1:1:1) (6)
Compound 6 was prepared following a procedure simi-
lar to that reported for 4 by using AgO3SCF3 (0.385 g,

A. Cerquetella et al. / Inorganica Chimica Acta 360 (2007) 2265–2270
2267
1.5 mmol), PPh3 (0.394 g, 1.5 mmol) and H2C(pzMe2
)
2
ðC52h; no: 14Þ, a = 7.926(1), b = 33.117(5), c = 10.928(2)
3
˚
˚
(0.594 g, 0.2 mmol); m.p. 176–178 ꢁC. Anal. Calc. for
A, b = 102.883(2)ꢁ, V = 2796 A . Dc (Z = 4) = 1.512 g
cmꢀ3. lMo = 0.82 mmꢀ1; specimen: 0.24 · 0.08 · 0.07 mm;
‘T’min/max = 0.90. 2hmax = 58ꢁ; Nt = 25604; N = 6958
(Rint = 0.026), No = 6149; R = 0.038, Rw = 0.047.
Variata. The oxygen atoms of the nitrate group were
modelled as disordered over two sets of sites, occupancies
refining to 0.866(7) and complement.
C30H31AgF3N4O3PS: C, 49.80; H, 4.32; N, 7.74. Found:
C, 50.02; H, 4.60; N, 7.91%. IR (nujol, cmꢀ1): 3132w,
. . .
1968br, 1895br, 1817br, 1770br (O3SCF3), 1553s m(C C,
•
. . .
C
N) 1290s, 1274s, 1245s, 1225s, 1164s, 1149s, 1094s
•
1
(O3SCF3), 636s, 572m, 519s, 504s, 434w, 341w. H NMR
(CDCl3): d, 1.97 (s, 6H, 5-CH3pz), 2.47 (s, 6H, 3-CH3pz),
5.88 (s, 2H, H4pz), 6.38 (s, 2H, CH2), 7.49 (m, 15H, CHPh).
31P{1H} NMR (CDCl3, 293 K): 17.2 (d, br,
1J(31P,Ag) = 600 Hz).
3. Results and discussion
The adducts AgX:PPh3:H2C(pz)2 (1:1:1) (H2C(pz)2 =
bis(pyrazolyl)methane, X = ClO4, NO3, SO3CF3) 1–3
(Chart 1) have been synthesized by reacting the N-donor
ligand with a MeCN solution containing equimolar quan-
tities of the PPh3 and of the corresponding silver salts.
When less than one equivalent of the H2C(pz)2 was used,
some unreacted starting material was often recovered from
the reaction. It is noteworthy that the ligands H2C(pz)2 and
H2C(pzMe2)2 reacted in a different manner. In fact com-
pounds AgX:PPh3:H2C(pzMe2)2 (1:1:1) 4–6 (Chart 1) could
be obtained only when a N-donor ligand:metal molar ratio
of 2:1 was employed. Displacement of the phosphine donor
from the silver centre in 1–6 was not observed either, when
1–6 was reacted with more than two equivalents of bis(pyr-
azolyl)alkanes. From the reaction between (PR3)4AgNO3
or (PPh3)4AgClO4 and bis(pyrazolyl)alkanes no adducts
were isolated.
The IR spectra (some selected data are reported in Sec-
tion 2) show all the bands required by the presence of the
organic N-donor and phosphine ligand. Weak CH stretch-
ing vibrations due to the pseudo-aromatic rings are
observed in the range 3150–3050 cmꢀ1, similar to those
previously found in several bis(pyrazol-1-yl)alkane and
pyrazole derivatives of zinc, cadmium, mercury and gold
compounds [18–21]. Several weak to medium absorptions
found between 1500 and 1600 cmꢀ1 may be due to a ring
breathing mode. Finally, in the region 900–600 cmꢀ1 some
absorptions assignable with certainty to C–H bending and
ring deformation were always detected [22].
2.2. Structural determinations
Full spheres of CCD area-detector diffractometer data
were measured (Bruker AXS instrument, x-scans; mono-
chromatic Mo Ka radiation; k = 0.71073 A; T ca. 153 K),
˚
yielding Nt(otal) reflections, these merging to N unique (Rint
cited) after ‘empirical’/multiscan absorption correction
(proprietary software), No with F > 4r(F) being considered
‘observed’ and used in the full matrix least square refine-
ments on jFj, refining anisotropic displacement parameter
forms for the non-hydrogen atoms, (x,y,z,Uiso H being
)
included constrained at estimates. Conventional residuals
R, Rw on jFj are cited at convergence (reflection weights:
(r2(F) + 0.000nwF2)ꢀ1). Neutral atom complex scattering
factors were employed within the XTAL 3.7 program system
[17]. Pertinent results are given in the table and figures, the
latter showing non-hydrogen atoms with 50% probability
amplitude ellipsoids, hydrogen atoms having arbitrary
˚
radii of 0.1 A.
2.2.1. Crystal/refinement data
2.2.1.1. AgClO4:PPh3: H2C(pzMe2
)
(1:1:1). MeCN
2
(4). C31H34AgClN5O4P, M = 714.9. Triclinic, space group
P1 ðC1i ; no: 2Þ, a = 8.364(1), b = 10.341(2), c = 19.042(3)
˚
A, a = 89.824(4), b = 83.061(4), c = 79.857(4)ꢁ, V =
3
1609 A . Dc (Z = 2) = 1.475 g cmꢀ3. lMo = 0.80 mmꢀ1
;
˚
specimen:
0.32 · 0.27 · 0.04 mm;
‘T’min/max = 0.85.
2hmax = 65ꢁ; Nt = 32547; N = 11238 (Rint = 0.038), No =
9408; R = 0.039, Rw = 0.051 (nw = 4).
The IR spectra of the perchlorato derivatives 1 and 4
show two absorptions characteristic of a perchlorate group:
a strong broad band in the range 1100–1050 cmꢀ1 (m3) and
a sharp medium or strong band at ꢁ625 cmꢀ1 (m4) [23].
2.2.1.2. AgNO3:PPh3: H2C(pzMe2)2 (1:1:1) (5). C29H31-
AgN5O3P, M = 636.4. Monoclinic, space group P21=c
Chart 1.

2268
A. Cerquetella et al. / Inorganica Chimica Acta 360 (2007) 2265–2270
These absorptions differ slightly from those reported for
[(PPh3)4Cu]ClO4 [24] and are indicative of a weakly inter-
acting perchlorate group [25] in accordance with the single
crystal X-ray study. The silver(I) nitrato derivatives 2 and 5
exhibit absorptions in the region 1400–1100 cmꢀ1 which
differ considerably from those found in [(PPh3)4Ag]NO3
[26]. In both derivatives m1 and m4 differ in frequency by
70–90 cmꢀ1, suggesting for this compound in the solid
state, the presence of a monodentate nitrato group [27].
In the IR spectra of derivatives 3 and 6, containing the
triflate group, absorptions in the 1000–1300 cmꢀ1 region
confirm the presence of unidentate weakly coordinated tri-
fluoromethanesulfonate groups [28].
ber of the latter from measurement of the J values in the
31P NMR spectra. On the basis of the detected values,
AgPN2 or AgPN2 coordination environments perturbed
by the presence of weakly bonded counter-ions or solvent
molecules are found. The magnitude of the Ag–P coupling
constants can be correlated to the counter-ion nature, the
lower values being found in the complexes containing the
more strongly coordinating NO3 anion.
The results of the ‘low’-temperature single crystal X-ray
studies are consistent, in terms of stoichiometry and con-
nectivity, with the formulations of 4 and 5 above. In each
case, a single molecule, devoid of crystallographic symme-
try, and, in the case of 4, accompanied by a well-defined
acetonitrile molecule of solvation, comprises the asymmet-
ric unit of the structure. In each case, the molecule
1
The H and 31P NMR spectra carried out in CDCl3 for
all compounds support the formulae proposed and show
that the N- and P-donors have not undergone any struc-
tural changes upon coordination. From comparisons of
chemical shift related to the same type of proton in the
free base and in the silver(I) phosphino derivatives, we
hypothesize that the complexes persist also in solution,
larger coordination shifts being observed with respect to
the analogous copper complexes [15,16]. We have found
a pattern of chemical shifts in keeping with what has been
previously described [29,30]. With exception of the 5-
methyl protons in H2C(pzMe2) derivatives, which exhibit
smaller coordination shifts to higher fields, all other pro-
ton signals shift to lower field upon coordination; the shift
is generally appreciable for the bridging CH2, 3-CH3 and
3-CH groups.
The metal–(N–N)2C rings are expected in our com-
pounds to be in the boat conformation, as confirmed by
the X-ray studies. Consequently the two N–CH2–N hydro-
gens ought to be different, cf. for example the AB2 pattern
being reported for [H2C(pz)2PtCl2] [31], in agreement with
the well-established inertness of platinum(II). However in
all compounds described here the N–CH2–N hydrogens
were found to be magnetically equivalent, at least at room
temperature, so that, even when dissociation is not a cause,
a rapid boat inversion must be assumed, probably through
M–N bond breaking.
The 31P NMR data (chemical shifts, Ag–31P coupling
constants) in CD3CN solutions of all complexes confirm
their stability in this solvent. The room temperature 31P
NMR spectra of complexes 2 and 4 consist of broad sing-
lets, presumably in consequence of exchange equilibria that
are reasonably fast in relation to the NMR time scale.
Exchange is quenched at low temperature, and single unre-
solved doublets, arising from coupling between the phos-
phorus and silver atoms, are observed in the accessible
temperature range. For all the other derivatives broad dou-
blets were also observed at room temperature, suggesting
that rapid exchange equilibria are not operative in these
compounds.
It has been proposed [26,32] that the spin–spin coupling
constant (J) between phosphorus and silver is dependant
on the number of coordinated phosphorus atoms in the sil-
ver complex, and that it is possible to determine the num-
Fig. 1. Projections of single molecules of AgX:PPh3:L, X = ClO4, NO3.

A. Cerquetella et al. / Inorganica Chimica Acta 360 (2007) 2265–2270
2269
Table 1
Selected molecular descriptors
X/ligand
OClO3/dpaa,b
ONO2/dpab
OClO3/H2C(pzMe2
)
(4)
ONO2/H2C(pzMe2
)
(5)c
2
2
˚
Distances (A)
Ag–P
Ag–N
2.358(2)
2.274(6)
2.330(6)
2.666(6)
2.3465(6)
2.280(2)
2.364(2)
2.452(2)
2.3694(7)
2.304(2)
2.320(2)
2.620(2)
2.3951(7)
2.370(3)
2.366(2)
Ag–O
2.437(3), 2.38(2)
Angles (ꢁ)
P–Ag–N
141.8(2)
135.90(5)
125.24(5)
79.20(8)
119.92(5)
83.61(7)
100.87(6)
111.3(2)
129.50(5)
128.08(5)
85.16(7)
122.79(6)
94.03(7)
83.70(7)
128.5(1)
126.35(6)
120.47(6)
83.12(8)
134.72(7), 97.1(4)
88.75(9), 126.9(4)
87.75(8), 101.2(4)
117.5(2), 122(1)
129.9(2)
80.3(2)
112.0(1)
85.0(2)
92.7(2)
115.8(2)
N–Ag–N
O–Ag–P
O–Ag–N
Ag–O–X
˚
Out-of-plane deviations of the silver atom (A)
C
4,5N(1)
0.12(1)
0.82(1)
0.166(4)
1.345(4)
0.080(4)
1.298(4)
1.133(5)
0.011(5)
C4,5N(2)
Triphenylphosphine ligand torsion angles (ꢁ); carbon atoms are denoted by number only
Ag–P–11–12
Ag–P–21–22
Ag–P–31–32
a
20.3(7)
38.6(7)
55.1(7)
12.0(2)
42.1(3)
44.9(2)
25.3(2)
28.2(2)
42.2(2)
7.4(2)
62.8(2)
56.8(2)
˚
Ag–O(2) is 3.020(2) A.
b
c
Refs. [1,2].
Ag–O(2,2 ) are 3.177(4) and 3.22(2) A.
0
˚
comprises a silver atom coordinated by a unidentate tri-
phenylphosphine and a chelating N,N0-bidentate ligand,
comprising a quasi-trigonal planar array about the silver
atom, the planarity perturbed by the approach of a unid-
entate oxyanion normal to the plane. The molecules are
depicted in Fig. 1, core geometries being given, together
with those of the counterpart dpa arrays [1,2], in Table
1. (It is of interest that anion rather than solvent approach
is the form of the out-of-plane weak interaction; Ag–
NCMe interactions are well known and well defined, but
in the present situation, at least, and in the context of
other undefined lattice forces, are not competitive with
that of the O-perchlorate.) The nitrate structure is of
interest, the nitrate ion being disordered over a pair of
sites, one predominant; in the alternative orientation, also
unidentate, this coordinating oxygen atom lies toward the
phosphorus donor, unusually so in the context of the
other related compounds of Refs. [1,2]. An interesting fea-
ture of the silver atom environments in both the present
and their dpa analogues (Table 1) is that, although here
and in the other derivatives of Refs. [1,2], there is little
or no evidence for any tendency in the silver atom envi-
ronment toward two-coordination, the pair of Ag–N dis-
tances being essentially equal in all cases, there is a
pronounced asymmetry in the deviation of the silver atom
from the pair of aromatic ligand planes coordinating it,
presumably concomitant on the interaction of these planes
(with substituents in the present cases) with the triphenyl-
phosphine ligand, an effect not evident in the compounds
of Refs. [1,2] where the constraints on coplanarity of the
two aromatic components of the N,N0-ligand are more
demanding, an effect seemingly not correlating with the
disposition of the donor plane with respect to the asym-
metry of the phosphine ligand. A further feature of inter-
est is that the present N,N0-ligand seemingly coordinates
less strongly than does the dpa ligand (Table 1), despite
the apparently alacrity with which L and related systems
form silver(I) complexes, cf. the readiness of dpa to
behave as a unidentate ligand [3].
Appendix A. Supplementary material
CCDC 609840 and 609841 contain the supplementary
crystallographic data for this paper. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/
conts/retrieving.html, or from the Cambridge Crystallo-
graphic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223-336-033; or e-mail: depos-
it@ccdc.cam.ac.uk. Supplementary data associated with
this article can be found, in the online version, at
doi:10.1016/j.ica.2006.11.004.
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