First structurally characterized silver(I) derivatives with nonfluorinated β-diketones

Article abstract of DOI:10.1021/ic0109391

Synthetic, spectroscopic, and single-crystal X-ray structural studies of diverse complexes of silver(I) acylpyrazolonate salts AgQ^R′ (QH = 1-phenyl-3-methyl-4-R′(C = O)-pyrazol-5-one; Q¹, R = Ph; Q², R′ = CF₃; Q³, R′ = Me) with neutral ligands L = unidentate PR₃ (R = Ph, o-tolyl, cyclohexyl) and Hmimt (1-methyl-2-mercaptoimidazole) and bidentate dppe (Ph₂P(CH₂)₂PPh₂) and trimen (N,N,N′-trimethylethylenediamine) define the donor capability of the anionic Q^R′ ligand in a variety of roles. In the free ligand Q³H (which crystallizes in the monoclinic space group C2/c (no. 15), Z = 8, unit cell parameters a = 17.981(6) A, b = 5.0641(4) A, c = 24.271(6) A, and β = 99.67-(2)°), the acidic OH group hydrogen-bonds intramolecularly to the adjacent pyrazolone oxygen, i.e., the two oxygen atoms are cis, true of the other Q^R′ species structurally characterized here in their anionic complexed forms, in which they chelate the silver in the usual β-diketonate manner, but not of the free anion, found in the array [Ag(Ph₃P)(Hmimt)₂](Q¹) (triclinic space group P1 (no. 2), Z = 2, unit cell parameters a = 11.553(1) A, b = 11.943-(1) A, c = 15.479(2) A, α = 74.829(2)°, β = 76.094(2)°, and γ = 78.185(2)°), or [Ag(trimen)Q¹] (monoclinic space group P2₁/c (no. 14), Z = 4, unit cell parameters a = 7.982(1) A, b = 12.299(2) A, c = 21.507(3) A, and β = 95.119(3)°), which forms an infinite one-dimensional polymer string, Q¹ linking successive silver(I) atoms by coordination by way of the unsubstituted nitrogen and the pyrazolonate oxygen. In all [Ag(R₃P)₂(chelate-Q¹)] (R =Ph, Cy) complexes, P₂Ag(O,O′) arrays are found (R = Ph, monoclinic space group C2/c (no. 15), Z = 8, unit cell parameters a = 16.193(8) A, b = 13.859(7) A, c = 39.306(7) A, and β = 100.02(3)°; R = Cy, triclinic space group P1 (no. 2), Z = 2, unit cell parameters a = 10.4655(9) A, b = 12.079(1) A, c = 22.804(2) A, α= 104.872(2)°, δ = 95.180(2)°, and γ = 104.144(2)°), also true of [Ag(Ph₃P)₂(O,O′-Q₂)] (triclinic space group P1 (no. 2), Z = 2, unit cell parameters a = 10.672(2) A, b = 10.710(2) A, c = 18.713(3) A, α = 87.573(2)°, β = 80.972(2)°, and γ = 81.734(2)°), whereas [Ag(o-tol₃P)Q¹] (monoclinic space group P2₁/c (no. 14), Z = 2 dimers, unit cell parameters a = 11.8221(6) A, b = 13.2601(6) A, c = 20.5141(10) A, and β = 91.758(1)°) exists as a dinuclear species containing two AgO₂NP units where the acylpyrazolonate is coordinated in a bridging O,O′-Q-N fashion. Silver atoms are four-coordinate in all except the Hmimt complex.

Full text of DOI:10.1021/ic0109391

Inorg. Chem. 2002, 41, 1151−1161
First Structurally Characterized Silver(I) Derivatives with Nonfluorinated
â-Diketones
,†
Augusto Cingolani,† Effendy,‡,§ Fabio Marchetti,* Claudio Pettinari,† Riccardo Pettinari,†
Brian W. Skelton,‡ and Allan H. White‡
Dipartimento di Scienze Chimiche, UniVersita` degli Studi di Camerino, Via S. Agostino 1,
62032 Camerino, Italy, Department of Chemistry, The UniVersity of Western Australia,
Crawley, Western Australia 6009, Australia, and Jurusan Pendidikan Kimia,
FMIPA UniVersitas Negeri Malang, Jalan Surabaya 6, Malang 65145, Indonesia
Received August 30, 2001
Synthetic, spectroscopic, and single-crystal X-ray structural studies of diverse complexes of silver(I) acylpyrazolonate
1
2
3
salts AgQR′ (QH ) 1-phenyl-3-methyl-4-R′(CdO)-pyrazol-5-one; Q , R ) Ph; Q , R′ ) CF ; Q , R′ ) Me) with
3
neutral ligands L ) unidentate PR (R ) Ph, o-tolyl, cyclohexyl) and Hmimt (1-methyl-2-mercaptoimidazole) and
3
bidentate dppe (Ph2P(CH ) PPh2) and trimen (N,N,N′-trimethylethylenediamine) define the donor capability of the
2 2
3
anionic QR′ ligand in a variety of roles. In the free ligand Q H (which crystallizes in the monoclinic space group
C2/c (no. 15), Z ) 8, unit cell parameters a ) 17.981(6) Å, b ) 5.0641(4) Å, c ) 24.271(6) Å, and â ) 99.67-
(2)°), the acidic OH group hydrogen-bonds intramolecularly to the adjacent pyrazolone oxygen, i.e., the two oxygen
atoms are cis, true of the other QR′ species structurally characterized here in their anionic complexed forms, in
which they chelate the silver in the usual â-diketonate manner, but not of the free anion, found in the array
1
[Ag(Ph3P)(Hmimt)2](Q ) (triclinic space group P1h (no. 2), Z ) 2, unit cell parameters a ) 11.553(1) Å, b ) 11.943-
1
(1) Å, c ) 15.479(2) Å, R ) 74.829(2)°, â ) 76.094(2)°, and γ ) 78.185(2)°), or [Ag(trimen)Q ] (monoclinic
space group P21/c (no. 14), Z ) 4, unit cell parameters a ) 7.982(1) Å, b ) 12.299(2) Å, c ) 21.507(3) Å, and
1
â ) 95.119(3)°), which forms an infinite one-dimensional polymer string, Q linking successive silver(I) atoms by
1
coordination by way of the unsubstituted nitrogen and the pyrazolonate oxygen. In all [Ag(R P)2(chelate-Q )] (R )
3
Ph, Cy) complexes, P Ag(O,O′) arrays are found (R ) Ph, monoclinic space group C2/c (no. 15), Z ) 8, unit cell
2
parameters a ) 16.193(8) Å, b ) 13.859(7) Å, c ) 39.306(7) Å, and â ) 100.02(3)°; R ) Cy, triclinic space
group P1h (no. 2), Z ) 2, unit cell parameters a ) 10.4655(9) Å, b ) 12.079(1) Å, c ) 22.804(2) Å, R )
2
104.872(2)°, â ) 95.180(2)°, and γ ) 104.144(2)°), also true of [Ag(Ph3P)2(O,O′-Q )] (triclinic space group P1h
(no. 2), Z ) 2, unit cell parameters a ) 10.672(2) Å, b ) 10.710(2) Å, c ) 18.713(3) Å, R ) 87.573(2)°, â )
1
80.972(2)°, and γ ) 81.734(2)°), whereas [Ag(o-tol3P)Q ] (monoclinic space group P21/c (no. 14), Z ) 2 dimers,
unit cell parameters a ) 11.8221(6) Å, b ) 13.2601(6) Å, c ) 20.5141(10) Å, and â ) 91.758(1)°) exists as a
dinuclear species containing two AgO NP units where the acylpyrazolonate is coordinated in a bridging O,O′-Q-N
2
fashion. Silver atoms are four-coordinate in all except the Hmimt complex.
Introduction
contacts in microelectronic devices or as components in high-
temperature superconducting materials, and also as coordina-
tion polymer species in inorganic crystal engineering.3 Recent
papers have described the synthesis and structural charac-
terization of Ag(I) derivatives with â-diketonates and several
Lewis base donors,4 presenting low or very low stability in
â-Diketonate complexes of coinage metal ions have proved
to be useful for several applications: in classical metal-
organic chemical vapor deposition (MOCVD),1 in super-
critical fluid transport (SFT) CVD2 of thin metal films as
* To whom correspondence should be addressed. E-mail: fabio.
marchetti@unicam.it. Fax: +39 0737/637345.
† Universita` degli Studi di Camerino.
(1) (a) The Chemistry of Metal CVD; Kodas, T. T., Hampden, Smith, M.
J., Eds.; VCH Publishers: New York, 1994. (b) Hampden-Smith, M.
J.; Kodas, T. T. Polyhedron 1995, 14, 699-732.
(2) Hansen, B. N.; Brooks, M. H.; Barkley, R. M.; Sievers, R. E. Chem.
Mater. 1992, 4, 749-752 and references therein.
‡ The University of Western Australia.
§ FMIPA Universitas Negeri Malang.
10.1021/ic0109391 CCC: $22.00 © 2002 American Chemical Society
Published on Web 02/14/2002
Inorganic Chemistry, Vol. 41, No. 5, 2002 1151

Cingolani et al.
air and solution, being easily hydrolyzed and decomposed
by contact with moisture. Among them, several silver(I)
derivatives containing alkenes4a,e,h or alkynes4g and only a
few with phosphines,4b-d amines,4j or sulfur donors4e,f,l have
been prepared, with no systematic study of the structural
variations induced by phosphines with different steric
hindrances yet reported. Moreover, the structural features of
Ag(I) derivatives with bidentate amines are poorly defined.4j
Building on our experience in the coordination chemistry of
several metals with the acylpyrazolone class of â-diketones
(QH),5 particularly with copper,6 tin,7 zinc, and cadmium,8
we extend our investigation to encompass the field of silver-
(I), for a variety of reasons. First, presumably due to the
presence of the pyrazole ring fused to one carbonyl group
in acylpyrazolones, their metal derivatives are generally more
stable relative to analogous acetylacetonates.6-9 Second, the
Figure 1. Proligands QH used in this work.
Ag(I) â-diketonates hitherto reported and structurally char-
acterized have always contained fluorinated â-diketones
(hfac, tfac, or fod).4 Third, the acylpyrazolones possess a
potentially donating nitrogen atom in the pz ring, which has
been shown to be involved in extensive H-bonding networks
influencing the supramolecular structure of several metal
acylpyrazolonates,6-8,10 and also their coordination to “soft”
metal atoms.11 In this work we describe the synthesis and
spectroscopic and structural characterization of a number of
silver(I) derivatives containing a variety of acylpyrazolones
(Figure 1), with coligating unidentate phosphines such as
Ph3P, Cy3P, and o-tol3P in diverse ligand/metal ratios, with
the bidentate bis(diphenylphosphino)ethane (dppe), or with
the S-donor 1-methyl-2-mercaptoimidazole (Hmimt) and the
N2-donor N,N,N′-trimethylethylenediamine (trimen). We
show here that Ag(I) can form air-stable derivatives with
nonfluorinated â-diketones, and that the combination of
acylpyrazolones with bidentate amines allows the formation
of one-dimensional polymeric species.
(3) (a) Withersby, M. A.; Blake, A. J.; Champness, N. R.; Hubberstey,
P.; Li, W,-S.; Schro¨der, M. Angew. Chem., Int. Ed. Engl. 1997, 36,
2327-2329. (b) Carlucci, L.; Ciani, G.; Proserpio, D. M.; Sironi, A.
Angew. Chem., Int. Ed. Engl. 1995, 34, 1895-1898. (c) Carlucci, L.;
Ciani, G.; Proserpio, D. M.; Sironi, A. J. Am. Chem. Soc. 1995, 117,
4562-4569. (d) Venkataraman, D.; Lee, S.; Moore, J. S.; Zhang, P.;
Hirsch, K. A.; Gardner, G. B.; Covey, A. C.; Prentice, C. L. Chem.
Mater. 1996, 8, 2030-2040. (e) Hirsch, K. A.; Wilson, S. R.; Moore,
J. S. Inorg. Chem. 1997, 36, 2960-2968. (f) Blake, A. J.; Champness,
N. R.; Crew, M.; Parson, S. New J. Chem. 1999, 23, 13-15.
(4) (a) Bailey, A.; Corbitt, T. S.; Hampden-Smith, M. J.; Duesler E. N.;
Kodas, T. T. Polyhedron 1993, 12, 1785-1792. (b) Dryden, N. H.;
Vittal, J. J.; Puddephatt, R. J. Chem. Mater. 1993, 5, 765-766. (c)
Lin, W.; Warren, T. H.; Nuzzo R. G.; Girolami, G. S. J. Am. Chem.
Soc. 1993, 115, 11644-11645. (d) Yuan, Z.; Dryden, N. H.; Vittal, J.
J.; Puddephatt, R. J. Can. J. Chem. 1994, 72, 1605-1609. (e) Xu, C.;
Corbitt, T. S.; Hampden-Smith, M. J.; Kodas T. T.; Duesler, E. N. J.
Chem. Soc., Dalton Trans. 1994, 2841-2849. (f) Xu, C.; Hampden-
Smith, M. J.; Kodas, T. T.; Duesler, E. N.; Rheingold A. L.; Yap, G.
Inorg. Chem. 1995, 34, 4767-4773. (g) Chi, K.-M.; Lin, C.-T.; Peng
S.-M.; Lee, G.-H. Organometallics 1996, 15, 2660-2663. (h) Doppelt,
P.; Baum T. H.; Ricard, L. Inorg. Chem. 1996, 35, 1286-1291. (i)
Chi, K.-M.; Chen, K.-H.; Lin H.-C.; Lin, K.-J. Polyhedron 1997, 16,
2147-2154. (j) Darr, J. A.; Poliakoff, M., Li, W.-S.; Blake, A. J. J.
Chem. Soc., Dalton Trans. 1997, 2869-2674. (k) Darr, J. A.; Poliakoff,
M.; Blake, A. J.; Li, W.-S. Inorg. Chem. 1998, 5491-5496. (l) Blake,
A. J.; Champness, N. R.; Howdle, S. M.; Webb, P. B. Inorg. Chem.
2000, 39, 1035-1038.
Experimental Section
General Remarks. Solvents were used as supplied or distilled
using standard methods. All chemicals were purchased from Aldrich
(Milwaukee) and used as received. The samples for microanalyses
were dried in a vacuum to constant weight (20 °C, ca. 0.1 Torr).
Elemental analyses (C, H, N, S) were performed in house with a
Fisons Instruments 1108 CHNS/O elemental analyzer. Molecular
weight determinations were performed in chloroform solution (m
) mol/kg of solvent) at 313 K with a Knauer membrane osmometer.
IR spectra were recorded from 4000 to 100 cm-1 using a Perkin-
(5) These molecules were first synthesised at the turn of the last century:
Stoltz, F. J. Prakt. Chem. 1897, 55, 145-148. The first work on the
use of acylpyrazolones as chelating agents was by Jensen: Jensen, B.
S. Acta Chem. Scand. 1959, 13, 1890-1896.
(6) (a) Marchetti, F.; Pettinari, C.; Cingolani, A.; Leonesi, D.; Camalli
M.; Pifferi, A. Polyhedron 1996, 15, 3835-3849. (b) Drozdov, A.;
Troyanov, S. I.; Fedorchenko, O.; Battiston, G.; Pettinari, C.; Marchetti
F.; Cingolani, A. Proceedings of the Twelfth European Conference
on CVD, vol II. J. Phys. IV 1999, 9, 929-934. (c) Marchetti, F.;
Pettinari, C.; Pettinari, R.; Cingolani, A.; Camalli M.; Spagna, R. Inorg.
Chim. Acta 2000, 299, 65-79. (d) Marchetti, F.; Pettinari, C.;
Cingolani, A.; Leonesi, D.; Drozdov A.; Troyanov, S. I. J. Chem. Soc.,
Dalton Trans. 1998, 3325-3333. (e) Pettinari, C.; Marchetti, F.;
Santini, C.; Pettinari, R.; Drozdov, A.; Troyanov, S. I. Inorg. Chim.
Acta 2001, 315, 88-95.
(7) (a) Pettinari, C.; Marchetti, F.; Cingolani, A.; Leonesi, D.; Mundorff,
E.; Rossi M.; Caruso, F. J. Organomet. Chem. 1998, 557, 187-201.
(b) Caruso, F.; Rossi, M.; Marchetti F.; Pettinari, C. Organometallics
1999, 18, 2398-2400. (c) Caruso, F.; Leonesi, D.; Marchetti, F.;
Rivarola, E.; Rossi, M.; Tomov, V.; Pettinari, C. J. Organomet. Chem.
1996, 519, 29-44. (d) Marchetti, F.; Pettinari, C.; Cingolani, A.; Gioia
Lobbia, G.; Cassetta, A.; Barba, L. J. Organomet. Chem. 1996, 517,
141-154. (e) Marchetti, F.; Pettinari, C.; Cingolani, A.; Brocanelli,
L.; Rossi, M.; Caruso, F. J. Organomet. Chem. 1999, 580, 344-353.
(f) Pettinari, C.; Marchetti, F.; Gregori, A.; Cingolani, A.; Tanski, J.;
Rossi, M.; Caruso, F. Inorg. Chim. Acta 1997, 257, 37-48. (g)
Pettinari, C.; Marchetti, F.; Cingolani, A.; Lorenzotti, A.; Mundorff,
E.; Rossi, M.; Caruso, F. Inorg. Chim. Acta 1997, 262, 33-46. (h)
Pettinari, C.; Marchetti, F.; Cingolani, A.; Marciante, C.; Spagna R.;
Colapietro, M. Polyhedron 1994, 13, 939-950.
1
Elmer System 2000 FT-IR instrument. H, 13C, 31P, and19F NMR
spectra were recorded on a VXR-300 Varian spectrometer operating
at room temperature (300 MHz for 1H, 75 MHz for 13C, 121.4 MHz
for 31P, and 282.3 MHz for 19F). Proton and carbon chemical shifts
are reported in parts per million vs Me4Si, while phosphorus
chemical shifts are reported in parts per million vs 85% H3PO4
(8) (a) Pettinari, C.; Marchetti, F.; Cingolani, A.; Pettinari, R.; Troyanov
S. I.; Drozdov, A. J. Chem. Soc., Dalton Trans. 2000, 831-836. (b)
Marchetti, F.; Pettinari, C.; Pettinari, R.; Arriva, D.; Troyanov S. I.;
Drozdov, A. Inorg. Chim. Acta 2000, 307, 97-105. (c) Marchetti, F.
Main Group Met. Chem. 2001, 24, 257-266.
(9) (a) Mahon, M. F.; Molloy, K. C.; Omotowa, B. A.; Mesubi, M. A. J.
Organomet. Chem. 1996, 525, 239-246. (b) Mahon, M. F.; Molloy,
K. C.; Omotowa, B. A.; Mesubi, M. A. J. Organomet. Chem. 1998,
560, 95-101.
(10) Pettinari, C.; Marchetti, F.; Cingolani, A.; Leonesi, D.; Troyanov, S.
I.; Drozdov, A. J. Chem. Soc., Dalton Trans. 1999, 1555-1562.
(11) Uzoukwu, B. A.; Adiukwu, P. U.; Al-Juaid, S. S.; Hitchcock, P. B.;
Smith, J. D. Inorg. Chim. Acta 1996, 250, 173-176.
1152 Inorganic Chemistry, Vol. 41, No. 5, 2002

Ag(I) DeriWatiWes with Nonfluorinated â-Diketones
and fluoro chemical shifts vs CFCl3. The electrical conductances
of the dichloromethane solutions were measured with a Crison
CDTM 522 conductimeter at room temperature. The proligands
Q1H, Q2H, and Q3H were synthesized according to the procedure
described by Jensen.5
[1J(31P-109Ag) ) 480 Hz; 1J(31P-107Ag) ) 415 Hz], -8.8dd
[1J(31P-109Ag) ) 514 Hz; 1J(31P-107Ag) ) 446 Hz] (T ) 218 K).
19F{1H} NMR (CDCl3): δ -72.1br (T ) 293 K); -71.6s, -75.5s
(T ) 218 K).
[Ag(Q2)(Cy3P)2] (5). Compound 5 was obtained similarly to 1.
31P{1H} NMR (CDCl3): δ 31.2br (T ) 293 K); 31.6dd
[1J(31P-109Ag) ) 501 Hz; 1J(31P-107Ag) ) 439 Hz] (T ) 218 K).
In dilute solution also a resonance at 11.8, due to free Cy3P, and a
double doublet at 43.5 [1J(31P-109Ag) ) 708 Hz; 1J(31P-107Ag) )
613 Hz] appeared at 218 K. 19F{1H} NMR (CDCl3): δ -72.8br
(T ) 293 K); -70.9s, -75.3s (T ) 218 K).
Synthesis of Complexes. [Ag(Q1)(Ph3P)2] (1). Silver nitrate (170
mg, 1 mmol) was added to a methanol solution (30 mL) of
triphenylphosphine (524 mg, 2.0 mmol). After a few minutes a
colorless precipitate was obtained. The mixture was then added to
a methanol solution (20 mL) of 1-phenyl-3-methyl-4-benzoylpyra-
zol-5-one (278 mg, 1 mmol) and sodium methoxide (54 mg, 1
mmol). A yellow precipitate slowly formed. The mixture was set
aside and stirred at room temperature for 1 h and then filtered.
The precipitate was washed with methanol (10 mol) and dried under
reduced pressure to constant weight. Yield: 87%. Mp: 168-169
°C. Anal. Calcd for C53H43AgN2O2P2: C, 69.97; H, 4.76; N, 3.08.
Found: C, 69.63; H, 4.65; N, 3.09. FW: 910. MW (CHCl3): 895
(c ) 0.9 × 10-2 m); 902 (c ) 1.1 × 10-2 m). IR (Nujol) data:
1615vs, ν(CdO); 523m, 512vs, 493s, ν(PsPh); 380m, 337m,
ν(AgsO). 1H NMR (CDCl3): δ 1.88s (3 H, C3-CH3); 7.10t, 7.20-
7.50m, 7.65-7.75m, 7.95d (40 H, aromatics of Q and Ph3P).13C-
{1H} NMR (CDCl3): δ 16.9 (s, C3-CH3), 120.5, 124.4, 127.6,
[Ag(Q3)(Ph3P)2] (6). Compound 6 was obtained similarly to 1.
31P{1H} NMR (CDCl3): δ 9.0s br (T ) 293 K); 9.7dd
[1J(31P-109Ag) ) 469 Hz; 1J(31P-107Ag) ) 406 Hz] (T ) 218 K).
[Ag(Q3)(Cy3P)2] (7). Compound 7 was obtained similarly to
1.31P{1H} NMR (CDCl3): δ 28.3br (T ) 293 K); 28.5dd
[1J(31P-109Ag) ) 488 Hz; 1J(31P-107Ag) ) 421 Hz] (T ) 218 K).
In dilute solution also a resonance at 11.8, due to free Cy3P, and a
double doublet at 43.4 [1J(31P-109Ag) ) 707 Hz; 1J(31P-107Ag) )
613 Hz] slowly appeared at 218 K.
[Ag(Q1)(Ph3P)]2 (8). Compound 8 has been synthesized similarly
to 1, but using only 1 mmol of triphenylphosphine. FW: 647. MW
(CHCl3): 664 (c ) 0.9 × 10-2 m); 777 (c ) 1.1 × 10-2 m).
31P{1H} NMR (CDCl3): δ 14.5s br (T ) 293 K); 16.3dd
[1J(31P-109Ag) ) 802 Hz; 1J(31P-107Ag) ) 696 Hz] (T ) 218 K).
[Ag(Q1)(Cy3P)]2 (9). Compound 9 has been synthesized sim-
ilarly to 8. FW: 665. MW (CHCl3): 721 (c ) 0.9 × 10-2 m); 803
(c ) 1.1 × 10-2 m). 31P{1H} NMR (CDCl3): δ 43.6dd
[1J(31P-109Ag) ) 777 Hz; 1J(31P-107Ag) ) 674 Hz] (T ) 293 K).
[Ag(Q1)(o-tol3P)]2 (10). Compound 10 has been synthesized
similarly to 8. Yield: 83%. Mp: 235-237 °C. Anal. Calcd for
C38H34AgN2O2P: C, 66.19; H, 4.97; N, 4.06. Found: C, 65.95; H,
5.07; N, 4.11. FW: 689. MW (CHCl3): 1056 (c ) 0.9 × 10-2 m);
1170 (c ) 1.1 × 10-2 m). IR (Nujol) data: 1632vs, ν(CdO); 462s,
3
128.1, 128.6, 142.0, 149.6 (s, Carom of Q1), 128.9 (d, JP-C ) 9.7
1
Hz, m-C of Ph3P), 130.5 (s, p-C of Ph3P), 131.5 (d, JP-C ) 32.2
Hz, C-P of Ph3P), 133.9 (d, 2JP-C ) 16.3 Hz, o-C of Ph3P), 104.8
(s, C4) 139.4 (s, C3) 165.5 (s, C5), 192.0 (s, CO). 31P{1H} NMR
(CDCl3): δ 8.7s br (T ) 293 K); 9.7dd [1J(31P-109Ag) ) 468
1
Hz; J(31P-107Ag) ) 405 Hz], 8.4dd [1J(31P-109Ag) ) 500 Hz;
1J(31P-107Ag) ) 433 Hz] (T ) 218 K).
[Ag(Q1)(Cy3P)2] (2). Compound 2 has been synthesized similarly
to 1. Yield: 55%. Mp: 147-149 °C dec. Anal. Calcd for C53H79-
AgN2O2P2: C, 67.29; H, 8.42; N, 2.96. Found: C, 67.14; H, 8.54;
N, 2.68. IR (Nujol) data: 1622vs, ν(CdO); 509s, ν(PsCy); 360m,
ν(AgsO). 1H NMR (CDCl3): δ 1.15-1.45m, 1.64-2.00m (66 H,
P-C6H11); 1.95s (3 H, C3-CH3); 7.10t, 7.26-7.30m, 7.40-7.45m,
7.55-7.62m, 8.03d (10 H, aromatics of Q).13C{1H} NMR
(CDCl3): δ 17.0 (s, C3-CH3), 26.1, 27.4, 30.6, 32.1 (s br,
(C6H11)3P), 119.4, 123.4, 127.7, 127.8, 128.3, 129.5, 142.3, 150.1
(s, Carom of Q1), 103.7 (s, C4) 140.0 (s, C3) 164.5 (s, C5), 190.3 (s,
CO). 31P{1H} NMR (CDCl3): δ 26.5s br (T ) 293 K); 28.0dd
[1J(31P-109Ag) ) 482 Hz; 1J(31P-107Ag) ) 419 Hz] (T ) 218 K).
In dilute solution also a resonance at 11.8, due to free Cy3P, and
double doublet at 43.4 [1J(31P-109Ag) ) 776 Hz; 1J(31P-107Ag) )
675 Hz] slowly appeared at 218 K.
1
438m, ν(Pso-tol); 343m, ν(AgsO). H NMR (CDCl3): δ 1.78s
(3 H, C3-CH3); 2.54s (9 H, o-CH3); 6.82t, 7.15t, 7.30-7.48m, 7.95d
(22 H, aromatics of Q and o-tol3P). 13C{1H} NMR (CDCl3): δ
17.0 (s, C3-CH3), 22.3 (s, o-CH3), 22.5 (s, o-CH3), 120.2, 124.1,
127.4, 128.1, 128.5, 129.6, 139.6, 142.2 (s, Carom of Q1), 126.8 (d,
3JP-C ) 7.3 Hz, m-CH of o-tol3P) 131.0 (d, 4JP-C ) 1.2 Hz, p-CH
3
of o-tol3P) 131.9 (d, JP-C ) 7.3 Hz, m-CH of o-tol3P) 133.0 (d,
2
2JP-C ) 6.1 Hz, o-CH of o-tol3P) 142.7 (d, JP-C ) 15.7 Hz,
o-C-CH3 of o-tol3P), 166.3 (s, C5), 192.1 (s, CO), C-P of o-tol3P
not observed. 31P{1H} NMR (CDCl3): δ -17.1d br (T ) 293 K);
[Ag(Q1)(o-tol3P)2] (3). Compound 3 has been synthesized
similarly to 1. Yield 75%. Mp: 140-142 °C dec. Anal. Calcd for
C59H55AgN2O2P2: C, 71.30; H, 5.58; N, 2.82. Found: C, 71.14;
H, 5.44; N, 2.97. IR (Nujol) data: 1632vs, ν(CdO); 462s, 438m,
1
-20.4dd [1J(31P-109Ag) ) 817 Hz; J(31P-107Ag) ) 709 Hz] (T
) 193 K).
[Ag(Hmimt)2(Ph3P)](Q1) (11). Compound 1 (909 mg, 1 mmol)
was dissolved in hot diethyl ether (50 mL), and 1-methylimidazo-
line-2-thione (Hmimt) was then added (218 mg, 2 mmol). A yellow
precipitate slowly formed. The mixture was set aside and stirred at
room temperature for 1 h and then filtered. The precipitate was
washed with diethyl ether (10 mol) and dried under reduced pressure
to constant weight. Yield: 75%. Mp: 108-110 °C. FW: 876.8.
MW (CHCl3): 845 (c ) 0.9 × 10-2 m); 868 (c ) 1.2 × 10-2 m).
Anal. Calcd for C43H37AgN6O2PS2: C, 58.97; H, 4.60; N, 9.60.
Found: C, 58.64; H, 4.52; N, 9.78. IR (Nujol) data: 2300-3200br,
1
ν(Pso-tol); 386w, ν(AgsO). H NMR (CDCl3): δ 1.74s (3 H,
C
3-CH3); 2.39s (18 H, o-CH3); 6.86t, 7.15t, 7.26-7.35m, 8.00d
(34 H, aromatics of Q and o-tol3P). 13C{1H} NMR (CDCl3): δ
16.6 (s, C3-CH3), 21.7, 22.0 (s, o-CH3), 120.7, 125.3, 127.7, 128.3,
128.8, 129.4, 129.8, 130.7, 140.5, 140.2 (s, Carom of Q1), 126.6 (d,
3JP-C ) 4.8 Hz, m-CH of o-tol3P) 130.2 (s, p-CH of o-tol3P) 131.3
3
2
(d, JP-C ) 5.5 Hz, m-CH of o-tol3P) 133.3 (d, JP-C ) 5.5 Hz,
o-CH of o-tol3P) 142.8 (d, 2JP-C ) 18.6 Hz, o-C-CH3 of o-tol3P),
102.2 (s, C4), 138.6 (s, C3), 176.9 (s, C5 and/or CO), C-P of
o-tol3P not observed. 31P{1H} NMR (CDCl3): δ -19.1s br (T )
293 K); -16.4dd [1J(31P-109Ag) ) 482 Hz; 1J(31P-107Ag) ) 418
Hz], -20.4dd [1J(31P-109Ag) ) 816 Hz; 1J(31P-107Ag) ) 707 Hz],
-29.0s (T ) 203 K).
1
ν(NsH‚‚‚O); 1620vs, ν(CdO); 517s, 512s, 503vs, ν(PsPh). H
NMR (CDCl3): δ 1.84s (3 H, C3-CH3); 3.53s, (6 H, N-CH3, of
Hmimt); 5.40br (2 H, N-H of Hmimt); 6.50d, (4 H, aromatics of
Hmimt); 7.10t, 7.25-7.35m, 7.42d, 7.98d, (25 H, aromatics of Q
and Ph3P). 13C{1H} NMR (CDCl3): δ 16.7 (s, C3-CH3), 34.2 (s,
N-CH3 of Hmimt), 120.4, 123.8, 127.7, 128.1, 142.2, 150.0 (s,
Carom of Q1), 116.2, 119.1, 129.7 (s, Carom of Hmimt), 128.7 (d,
[Ag(Q2)(Ph3P)2] (4). Compound 4 was obtained similarly to 1.
31P{1H} NMR (CDCl3):
δ 9.5br (T ) 293 K); 10.5dd
Inorganic Chemistry, Vol. 41, No. 5, 2002 1153

Cingolani et al.
3JP-C ) 9.6 Hz, m-C of Ph3P), 129.9 (s, p-C of Ph3P), 132.8 (d,
1JP-C ) 24.0 Hz, C-P of Ph3P), 133.8 (d, 2JP-C ) 16.5 Hz, o-C of
Ph3P), 100.3 (s, C4), 139.6 (s, C3), 177.3 (s, C5 and/or CO). 31P
NMR (CDCl3): δ 6.1s br (T ) 293 K); 6.8dd [1J(31P-109Ag) )
green precipitate immediately formed. The mixture was set aside
and stirred at room temperature for 1 h, and then it was filtered.
The precipitate was washed with diethyl ether (10 mol) and
dried under reduced pressure to constant weight. It was shown to
be soluble in DMSO and chlorinated solvents. Yield: 65%. Mp:
151-152 °C dec. Anal. Calcd for C22H27AgN4O2: C, 54.22; H,
5.58; N, 11.50. Found: C, 54.02; H, 5.70; N, 11.65. IR (Nujol)
data: 1612vs, ν(CdO); 335m, ν(AgsO); 284m, ν(AgsN). 1H
NMR (CDCl3): δ 2.11s (6 H, N(CH3)2); 2.15s (3 H, N′ CH3 of
trime); 2.26s (3 H, C3-CH3); 2.20-2.24m, 2.42-2.45m (4 H,
N-CH2CH2-N′ of trime); 7.15t, 7.22-7.40m, 7.58d, 7.75-7.80m
(10 H, aromatics of Q).13C{1H} NMR (CDCl3): δ 18.4 (s, C3-
CH3), 38.6 (s, N-CH3), 49.3 (s, N(CH3)2), 49.4, 58.8 (s, N(CH2)2N),
123.0, 125.5, 127.4, 128.8, 129.0, 130.2, 141.3, 154.2 (s, Carom of
Q1), 103.4 (s, C4), 139.5 (s, C3), 163.9 (s, C5), 190.3 (s, CO).
[Ag(Q2)(trimen)] (16). Compound 16 has been synthesized
similarly to 15. It was shown to be soluble in DMSO and chlorinated
solvents. 1H NMR (CDCl3): δ 2.10s (6 H, N(CH3)2 trime); 2.23s (3
H, N′ CH3 trime); 2.34q (3 H, C3-CH3); 2.28-2.34m, 2.58-2.66m
(4 H, N-CH2CH2-N′trime); 2.94br (1 H, N′ Htrime); 7.15t, 7.26t,
7.54d, (5 H, N-C6H5). 19F{1H} NMR (CDCl3): δ 76.0br (293 K).
1
523 Hz; J(31P-107Ag) ) 494 Hz] (T ) 218 K).
[Ag(dppe)2](Q1) (12). Compound 1 (909 mg, 1 mmol) was
dissolved in hot diethyl ether (50 mL), and bis(diphenylphosphino)-
ethane (dppe) was then added (796 mg, 2 mmol). The clear solution
was set aside and stirred at room temperature for 4 h, and then
solvent was removed and chloroform added (20 mL). The mixture
was filtered, to remove NaNO3, and n-hexane added (40 mL). A
yellow precipitate immediately formed, which was filtered off,
washed with methanol (10 mol), and dried under reduced pressure
to constant weight. Yield: 66%. Mp: 94-95 °C. FW: 1182. MW
(CHCl3): 540 (c ) 0.9 × 10-2 m); 588 (c ) 1.2 × 10-2 m). Anal.
Calcd for C69H61AgN2O2P4: C, 70.11; H, 5.20; N, 2.37. Found:
C, 69.88; H, 512; N, 2.32. Molar conductance ΛM in dichlo-
romethane solution: 32.5 Ω-1 cm2 mol-1. IR (Nujol) data: 1632vs,
ν(CdO); 509s, ν(PsPh). 1H NMR (CDCl3): δ 2.30s (3 H,
C
3-CH3); 2.40-2.45m (4 H, P-CH2CH2P of dppe); 7.18-7.32m,
7.36-7.40m, 8.05d (50 H, aromatics of Q1 and dppe). 13C{1H}
NMR (CDCl3): δ 17.1 (s, C3-CH3), 25.6 (s br, P-CH2CH2-P of
dppe), 119.6, 122.4, 124.8, 126.3, 127.3, 128.1, 128.3, 128.7, 135.9,
140.3.1 (s, Carom of Q2), 129.2 (s, m-C of Ph-P) 130.6 (s, p-C of
Ph-P) 132.1 (br, C-P of Ph-P) 132.5 (s, o-C of Ph-P), resonances
of C3, C4, C5, and CO were not observed. 31P{1H} NMR
(CDCl3): δ 5.6d br (T ) 293 K); 5.6dd [1J(31P-109Ag) ) 265 Hz;
1J(31P-107Ag) ) 230 Hz] (T ) 218 K).
All other analytical and spectroscopic data of derivatives 4-9,
13, and 16 are available as Supporting Information.
X-ray Crystallographic Studies. Crystals suitable for structural
analysis of Q3H, 1, 2, 4, 10, 11, and 15 were grown from chloroform
at 4 °C. They were all pale yellow, except 15, which was light
green. Full spheres of CCD area detector diffractometer data were
measured (Bruker AXS instrument; ω-scans; monochromatic Mo
KR radiation, λ ) 0.71073 Å; T as specified; 2θmax as specified),
yielding Ntotal reflections, merging to N unique reflections (Rint
quoted) after “empirical”/multiscan absorption correction (propri-
etary software), No with F > 4σ(F) considered “observed” and used
in the full-matrix least-squares refinement, refining anisotropic
thermal parameter forms for the non-hydrogen atoms (x, y, z, Uiso)H
treatment as indicated. [Exception: For 1 and Q3H hemispheres of
data were measured using an Enraf-Nonius CAD-4 sequential/single
counter instrument (2θ/θ scan mode)]. Conventional residuals R
Derivative 12 could also be synthesized by the following
alternative method.
Silver nitrate (170 mg, 1 mmol) was added to a methanol solution
(30 mL) of dppe (796 mg, 2.0 mmol). Then the mixture was added
to a methanol solution (20 mL) of 1-phenyl-3-methyl-4-ben-
zoylpyrazol-5-one (278 mg, 1 mmol) and sodium methoxide (54
mg, 1 mmol). The clear solution was set aside and stirred at room
temperature for 4 h, and then solvent was removed and chloroform
added (20 mL). The mixture was filtered, to remove NaNO3, and
n-hexane added (40 mL). A yellow precipitate immediately formed,
which was filtered off, washed with methanol (10 mol), and dried
under reduced pressure to constant weight.
2 2
(∑∆/∑|Fo|) and Rw ([∑(ω∆2/∑(ωFo ) )]1/2) (weights: (σ2(F) +
0.0004F2)-1) are quoted at convergence. Pertinent results are given
in the tables and figures, full details being deposited. In the figures
displacement ellipsoid amplitudes are 20% (room temperature) and
50% (low temperature) for the non-hydrogen atoms, hydrogen atoms
having arbitrary radii of 0.1 Å. Further individual variations are as
follows:
[Ag(dppe)2](Q2) (13). Compound 13 has been synthesized
similarly to 12.31P{1H} NMR (CDCl3): δ 5.7d br (T ) 293 K);
1
5.7dd [1J(31P-109Ag) ) 264 Hz; J(31P-107Ag) ) 231 Hz] (T )
218 K). 19F{1H} NMR (CDCl3): δ 75.2 (T ) 293 K).
[Ag(Q1)dppe)] (14). Silver nitrate (170 mg, 1 mmol) was added
to a methanol solution (30 mL) of dppe (398 mg, 1.0 mmol). The
mixture was then added to a methanol solution (20 mL) of 1-phenyl-
3-methyl-4-benzoylpyrazol-5-one (278 mg, 1 mmol) and sodium
methoxide (54 mg, 1 mmol). A brown precipitate immediately
formed. The mixture was set aside and stirred at room temperature
for 1 h, then filtered, washed with methanol (10 mol), and dried
under reduced pressure to constant weight. Derivative 14 is insoluble
in all solvents, except DMSO. Yield: 85%. Mp: 190-191 °C.
Anal. Calcd for C43H237AgN2O2P2: C, 65.91; H, 4.76; N, 3.57.
Found: C, 65.72; H, 4.70; N, 3.65. Molar conductance ΛM in
DMSO solution: 12.4 Ω-1 cm2 mol-1. IR (Nujol) data: 1613vs,
(1) A difference map residue was assigned as a water molecule
oxygen, fully populated after trial refinement, hydrogens not located.
A Gaussian absorption correction was applied.
(15) Diamine ring methylene groups were modeled as disordered,
concerted, over two sets of sites, occupancies 0.66(1) and comple-
ment.
(2) Difference map residues were modeled in terms of acetone
of solvation, site occupancy set at unity after trial refinement.
(Q3H) No absorption correction was applied.
Atoms numberings of the Q ligand cores are based on the
following scheme:
1
ν(CdO); 511s, ν(PsPh). H NMR (DMSO-d6): δ 2.22s (3 H,
C
3-CH3); 2.55s (4 H, P-CH2CH2-P); 7.22-7.55m, 7.58-7.75m
(30 H, aromatics of Q).
[Ag(Q1)(trimen)] (15). Silver nitrate (170 mg, 1 mmol) was
added to a methanol solution (30 mL) of 1-phenyl-3-methyl-4-
benzoylpyrazol-5-one (278 mg, 1 mmol) and sodium methoxide
(54 mg, 1 mmol), and trime then added (102 mg, 1 mmol). A dark
1154 Inorganic Chemistry, Vol. 41, No. 5, 2002

Ag(I) DeriWatiWes with Nonfluorinated â-Diketones
Scheme 1
Scheme 3
Scheme 4
Scheme 2
acylpyrazolonate oxygen, as found in the solid state (see the
infrared and structural discussion below).
By interaction of derivatives 1 and 4 with excess dppe in
hot diethyl ether, the derivatives 12 and 13, respectively,
have been obtained (Scheme 4).
Results and Discussion
From the interaction of 1 equiv of AgNO3 with 1 equiv
of the proligands QH in methanol, in the presence of 1 equiv
of NaOCH3 and 2 equiv of R3P ligands, we have synthesized
the derivatives 1-7 (Scheme 1).
They are very soluble in DMSO, acetone, diethyl ether,
aromatic hydrocarbons, and chlorinated solvents, in which
they are nonelectrolytes.
On the other hand, with equimolar amounts of all reactants,
the derivatives 8-10 have been obtained (Scheme 2).
They are soluble in DMSO, acetone, and chlorinated
solvents, in which they are nonelectrolytes. They exist in
the solid state as dinuclear species (see the structural
discussion below), but in solution vaporimetric molecular
weight determinations suggest they are almost completely
dissociated into the mononuclear fragments.
The reaction of derivative 1 with 2 equiv of the unidentate
S-donor ligand Hmimt in hot diethyl ether affords the
derivative 11 (Scheme 3).
Derivative 11 is very soluble in most organic solvents and
a is non-electrolyte in acetone and dichloromethane. This
may be due to an ion-pairing effect, resulting from H-bonding
between the hydrogen of the coordinated Hmimt and the
These are 1:1 electrolytes in dichloromethane, vaporimetric
molecular weight determinations being consistent with an
ionic structure. These derivatives can also be synthesized
by direct interaction of 1 equiv of AgNO3 with 1 equiv of
the proligands QH in methanol, in the presence of 1 equiv
of NaOCH3 and 2 equiv of dppe. An excess of the bidentate
chelating dppe always displaces the acylpyrazolone from the
coordination sphere of silver. If the reaction is carried out
using equivalent amounts of AgNO3, Q1H, NaOCH3, and
dppe in methanol, the 1:1:1 derivative 14 is obtained, which
is insoluble in all common solvents except DMSO, presum-
ably polymeric.
These results led us to investigate the behavior of a
bidentate amine, exemplified by trimen, which, like dppe,
can form five-membered chelate rings, but possesses two
nitrogen atoms which are harder donors than phosphorus.
The trimen donor has been previously used to form the
derivative [Ag(hfac)(trimen)],4j but its solid-state structure
has not been investigated.
The attempted displacement of Q- or Ph3P from the silver
environment in 1 or 4 by a large excess of trimen in Et2O
was unsuccessful, whereas, from the direct interaction with
Inorganic Chemistry, Vol. 41, No. 5, 2002 1155

Cingolani et al.
Scheme 5
Scheme 6
split into one or two double doublets, from which it is
possible to determine the J(109Ag-31P) and J(107Ag-31P)
coupling constants. This indicates that 1-13 undergo ex-
change at room temperature, leading to partial loss of Ag-P
coupling information. For previous silver phosphine â-dike-
tones, the mechanism proposed was a reversible dissociation
of the anionic â-diketonate ligand in solution.4d The 19F NMR
spectra of the derivatives 4 and 5, which contain the
fluorinated Q2, further support this hypothesis: the broad
signal detected at room temperature splits into one signal
due to anionic Q2 at -75 ppm and another one, at higher
field, due to the complex [Ag(Q2)(R3P)2]. The absence of
conductivity in dichloromethane is presumably a conse-
quence of ion-pairing effects.
1
1
equimolar amounts of the reactants in methanol, derivatives
15 and 16 were obtained (Scheme 5).
For [Ag(Q)(R3P)2]-type complexes the chemical shift
They are soluble in DMSO but only slightly soluble in
acetone and chlorinated solvents, where they are nonelec-
trolytes. They exist in the solid state as polymers (see the
structural discussion below).
∆δ(31P{1H}) ()δcomplex
δphosphine) values lie in the range
-
13-20 ppm, independent of the nature of the acylpyra-
zolonate donor. The 1J(Ag-P) coupling constants, which are
determined mainly by the bond orbital overlap between Ag
and P on the basis of the Fermi contact term,14 can be related
to the number of coordinated phosphines and covalent vs
ionic character of Ag-P bonds.15 In the present complexes
the 1J(107Ag-31P) values range from 230 to 709 Hz and the
1J(109Ag-31P) values from 264 to 817 Hz.
In the case of derivatives 1 and 4, the broad absorptions
detected at room temperature split into two pairs of double
doublets on lowering of the temperature, in accordance with
the presence of two different Ag-P bonds (see the structural
discussion of 1 and 4 below).
Derivative 3, containing the bulky o-tol3P ligand, partially
dissociates in CDCl3 solution (Scheme 6), the resonances
of both Ag(Q1)(o-tol3P)2 and Ag(Q1)(o-tol3P) species, to-
gether with the signal due to the free phosphine at -29.0
ppm, being observed in the 31P NMR spectra. The formation
of derivative 10 from concentrated chloroform solution of 3
gives further support to the possibility of dissociation.
In the cyclohexylphosphine derivatives 2, 5, and 7,
dissociation occurs in dilute solution several hours after
dissolution of the samples: the signal of free Cy3P and an
Spectroscopic Characterization. The infrared spectra of
derivatives 1-12 show the presence of the deprotonated Q
ligand: the strong broad band around 3000 cm-1 arising from
intramolecular OH‚‚‚O bonding disappears after coordi-
nation. By contrast, the strong absorption ascribed to the
CdO stretching seems almost unaffected, only a slight
shift to lower frequencies being observed, as previously
found in the spectra of analogous copper(I) acylpyra-
zolonates.6 In derivative 11 a broad absorption between
2300 and 3200 cm-1 is indicative of H-bonding between
the H atom of Hmimt and the Q1 donor oxygen, as found in
the crystal structure (see below). By comparison with the
spectrum of the free acylpyrazolone in the far-infrared region,
we have tentatively assigned a number of absorptions to
ν(Ag-O), ν(Ag-N), and ν(Ag-S) modes.12
1
The H NMR spectra of 1-16 show resonances and
integration in agreement with the formulas proposed. The
resonances are broad, especially in the spectra of derivatives
1-7, suggesting fluxionality in solution.
The 13C NMR spectra of derivatives 1-10 exhibit one set
of carbon resonances. In all R3P-containing compounds the
presence of further doublets due to C-P coupling assists in
the assignment of signals arising from the C atoms of the
phosphine ligand.13
(14) Pople, J. A. Santry, D. P. Mol. Phys. 1964, 8, 1-18.
(15) (a) Muetterties, E. L.; Alegranti, C. W. J. Am. Chem. Soc. 1970, 92,
4114-4115. (b) Muetterties, E. L.; Alegranti, C. W. J. Am. Chem.
Soc. 1972, 94, 6386-6391. (c) van der Ploeg, A. F. M. J.; van Koten,
G.; Spek, A. L. Inorg. Chem. 1979, 18, 1052-1060. (d) van der Ploeg,
A. F. M. J.; van Koten, G. Inorg. Chim. Acta 1981, 51, 225-239. (e)
Barrow, M.; Bu¨rgi, H.-B.; Camalli, M.; Caruso, F.; Fischer, E.;
Venanzi, L. M.; Zambonelli, L. Inorg. Chem. 1983, 22, 2356-2362.
(f) Socol, S. M.; Verdake, R. A. Inorg. Chem. 1984, 23, 3487-3493.
(g) Socol, S. M.; Jacobson, R. A. Verkade, J. G. Inorg. Chem. 1984,
23, 88-94. (h) Barron, P. F.; Dyason, J. C. Healy, P. C.; Engelhardt,
L. M.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans.
1986, 1965-1970. (i) Camalli, M.; Caruso, F. Inorg. Chim. Acta 1987,
127, 209-213. (i) Dean, P. A: W. Vittal, J. J.; Srivastava, R. S. Can.
J. Chem. 1987, 65, 2628-2633. (j) Camalli, M.; Caruso, F. Inorg.
Chim. Acta 1988, 144, 205-211. (k) Obendorf, D.; Probst, M.;
Peringer, P.; Falk, A.; Muller, N. J. Chem. Soc., Dalton Trans. 1988,
1709-1711. (l) Bowmaker, G. A.; Effendy; Harvey, P. J.; Healy, P.
C.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 1996,
2459-2466.
1H and 13C NMR spectra of derivatives 15 and 16, which
contain the trimen donor, appear consistent with dissociation
of the polymeric chain and coordination of the N2-donor to
the {Ag(Q)} fragment, providing no further insight into the
solution structures.
The room temperature 31P NMR spectra of derivatives
1-13 generally exhibit broad single resonances which, on
cooling of the samples at 218 or even to 193 K, generally
(12) Infrared and Raman Spectra of Inorganic and Coordination Com-
pounds, 4th ed.; Nakamoto, K., Ed.; Wiley-Interscience: New York,
1986.
(13) Pettinari, C.; Marchetti, F.; Polimante, R.; Cingolani, A.; Portalone,
G.; Colapietro, M. Inorg. Chim. Acta 1996, 249, 215-229.
1156 Inorganic Chemistry, Vol. 41, No. 5, 2002

Ag(I) DeriWatiWes with Nonfluorinated â-Diketones
Figure 3. Molecular projection of 2.
Figure 2. Molecular projection of 1.
additional double doublet, with the J(Ag-P) corresponding
to a Ag(Q)(Cy3P) species, slowly appear.
In the low-temperature 31P NMR spectra of the derivatives
8-10, containing only one R3P, one double doublet was
detected, 1J(109Ag-31P) and 1J(107Ag-31P) being 802 and 696
Hz for 8, 777 and 674 Hz for 9, and 817 and 709 Hz for 10,
1
respectively. These high J(Ag-P) values may be rational-
ized in terms of formation of a mononuclear Ag(Q1)(R3P)
fragment, containing an sp-hybridized silver,15f arising from
the dissociation of the dinuclear species, as indicated by
molecular weight values in chloroform.
The derivative 11 shows one double doublet at low
temperature; 1J(109Ag-31P) and 1J(107Ag-31P) are larger (523
and 494 Hz, respectively) than those found for 1-7 and
consistent with the presence of only one phosphine on a
tricoordinate silver atom.
Figure 4. Molecular projection of 4.
The ionic derivatives 12 and 13 present identical low-tem-
1
1
perature 31P spectra, with J(109Ag-31P) and J(107Ag-31P)
having the values 265 and 230 Hz, respectively, typical of
compounds with a AgP4 central core.15,16
Structural Discussion. The results of the single-crystal
X-ray structure determinations are consistent with the sto-
ichiometries and connectivities implied in the above formu-
las; in each case, one formula unit, devoid of crystallographic
symmetry, comprises the asymmetric unit of the structure.
All contain Q moieties in various forms; the methyl-
substituted ligand, crystallizing nicely as Q3H, provides an
example of a parent undeprotonated ligand form (drawing
given in the Supporting Information); in derivatives 1 (Figure
2), 2 (Figure 3), and 4 (Figure 4), the Q1 and Q2 ligands are
found as simple chelates, in 10 (Figure 5) and 15 (Figure
6), they are found with O-Q1-N and O,O′-Q1-N bridges,
respectively, and finally, in the derivative 11 (Figure 7), the
anionic ligand Q1 is totally displaced from the coordination
environment of the metal by other ligands, and provides an
Figure 5. Molecular projection of 10.
example of an anionic form. Many of the determinations are
nicely precise, as a consequence of the availability of full
spheres of extensive data at low temperature, permitting a
usefully comparative array of ligand geometries, as presented
in Table 1; we comment on them further after consideration
of the individual structures.
(16) (a) Di Bernardo, P.; Dolcetti, G.; Portauova, R.; Tolazzi, M.; Tomat,
G.; Zanonato P. Inorg. Chem. 1990, 29, 2859-2862. (b) Harker, C.
S. W., Tiekink, E. R. T. J. Coord. Chem. 1990, 21, 287-293.
Crystal Structure of Q3H. A representative structure of
a QH ligand, in its neutral O-protonated acid form, is
Inorganic Chemistry, Vol. 41, No. 5, 2002 1157

Cingolani et al.
Table 1. Comparative Geometries of Ligands Q in Various Formsa
10
Q1/O,O′-
15
2
HQ3
11
chelated Q1/O,N- Q1/simple
bridge bridging chelate
ligand/mode
N(1)-C(11)
Q3/acid Q1/anion
Distances (Å)
1.427(2) 1.410(3) 1.417(2) 1.416(4) 1.410(2)
1.395(3) 1.391(1) 1.404(2) 1.399(4) 1.402(2)
1.312(2) 1.322(2) 1.326(2) 1.321(4) 1.312(3)
1.493(3) 1.495(2) 1.494(2) 1.482(5) 1.492(3)
1.424(2) 1.422(3) 1.422(2) 1.409(4) 1.439(2)
1.392(2) 1.415(2) 1.435(2) 1.436(5) 1.435(2)
1.345(2) 1.385(1) 1.390(2) 1.406(5) 1.387(2)
1.316(2) 1.282(1) 1.254(2) 1.250(4) 1.250(2)
1.428(2) 1.449(2) 1.432(2) 1.452(5) 1.429(2)
1.247(2) 1.240(2) 1.248(2) 1.231(4) 1.249(2)
1.487(3) 1.499(2) 1.493(2) 1.504(5) 1.500(2)
N(1)-N(2)
N(2)-C(3)
C(3)-C(31)
C(3)-C(4)
C(4)-C(5)
C(5)-N(1)
C(5)-O(5)
C(4)-C(41)
C(41)-O(41)
C(41)-C(411)
O(41)‚‚‚O(5)
2.587(2)
2.972(2)
2.992(2)
Angles (deg)
Figure 6. Projection of the ion pair of 11.
C(11)-N(1)-N(2)
C(11)-N(1)-C(5)
N(2)-N(1)-C(5)
N(1)-N(2)-C(3)
N(2)-C(3)-C(4)
N(2)-C(3)-C(31)
C(31)-C(3)-C(4)
C(3)-C(4)-C(5)
C(3)-C(4)-C(41)
C(5)-C(4)-C(41)
C(4)-C(41)-O(41)
119.0(1) 118.96(9) 119.1(1) 119.6(2) 118.9(1)
130.9(1) 128.62(9) 129.3(1) 128.7(3) 128.6(1)
110.1(1) 112.20(9) 111.4(1) 111.6(2) 112.1(1)
106.1(1) 105.0(1) 106.1(1) 105.8(2) 105.7(1)
111.5(1) 112.3(1) 111.6(1) 112.3(3) 112.3(1)
119.4(2) 120.1(1) 118.8(1) 119.0(3) 117.9(2)
129.1(2) 127.5(1) 129.4(1) 128.6(3) 129.7(2)
104.0(1) 105.4(1) 105.9(1) 106.3(3) 104.9(1)
135.6(1) 125.9(1) 130.1(1) 123.9(3) 130.2(2)
120.4(1) 128.6(1) 123.9(1) 129.8(3) 124.3(1)
118.7(2) 121.7(1) 123.4(1) 121.0(3) 124.4(2)
C(4)-C(41)-C(411) 121.3(2) 119.9(1) 119.9(1) 121.7(3) 119.1(1)
O(41)-C(41)-C(411) 120.0(2) 118.4(1) 116.7(1) 117.2(3) 116.5(2)
N(1)-C(5)-C(4)
N(1)-C(5)-O(5)
C(4)-C(5)-O(5)
108.4(1) 105.10(9) 104.8(1) 103.9(3) 104.9(1)
124.8(1) 122.9(1) 124.1(1) 123.6(3) 123.4(2)
126.9(1) 131.6(1) 131.1(1) 132.5(3) 131.6(2)
Interplanar Dihedral Angles (deg)
C6(1)/N2-C3
5.33(1) 32.92(6) 6.96(5)
31.2(1) 6.29(7)
C(4(n))3-O(4)/N2-C3 2.71(8) 32.61(6) 21.69(5) 24.9(1) 12.83(6)
Figure 7. Section of the polymer of 15.
C(4(n))3-O(4)/C6(41)
25.87(6) 50.27(6) 29.9(1) 70.94(8)
a
Examples are given of the parent acid, as HQ3, the anion, as found in
11 as Q1, the coordinated ligand, in two bridging modes as in 10 and 15,
and a simple chelate, as most precisely exemplified in 2. The determination
of HQ3 was at ca. 300 K, the remainder at ca. 153 K.
provided by Q3H, the molecules packing in herringbone
fashion in projection down a (Figure deposited as part of
the supporting information), seemingly little affected by any
intermolecular interactions potentially arising out of hydrogen
bonds between the acidic OH groups peripheral to the central
ring and basic entities of the neighbors.17 Rather, the acidic
hydrogen atom bonds intramolecularly to the adjacent ketonic
oxygen atom of the acetyl group to which it lies cis, poised
for chelating, which, in this case, pertains to the hydrogen,
seemingly unsymmetrically disposed (H(5)‚‚‚O(5,41) ) 1.16-
(3), 1.51(3) Å). The non-hydrogen skeleton of the whole
molecule is quasi-planar (Table 1). Its geometry is generally
in agreement with those of other 4-acyl-5-pyrazolones from
previously reported crystal structures.17
(Figure 3), where the disposition of the P-Ag-P array is
more nearly linear (142.12(1)°), with concomitantly shorter
Ag-P distances (2.4342(6) and 2.3992(5) Å). The O-Ag-O
bite angles are 73.0(2)° in 1, 75.91(5)° in 2, and 73.6(4)° in
4. In the analogous crystal structure of [Ag(hfac)(Me3P)2],4c
despite the use of the seemingly less hindered phosphine
Me3P, the distortion is higher, P-Ag-P being 159.4(2)° and
the O-Ag-O bite angle 70.3(7)°, with appreciably longer
Ag-O (2.45(2) and 2.64(2) Å) but shorter Ag-P (2.335(9)
and 2.417(9) Å) distances, in accordance with the higher
electron-donating power of Me3P with respect to Ph3P, and
the diminished basicity of hfac (which contains two electron-
withdrawing CF3 groups) with respect to Q1 or Q2. The Cy3P
ligand conformations of 2 are of a familiar type18 (Table 2),
while those of the PPh3 ligands throughout 1 and 4 are quite
similar.6a,c In all three complexes, the silver atom lies well
out of the essentially planar C3O2 array: (δ Ag(Å), ø2 plane)
0.824(2), 5 × 103 (2); 1.26(1), 173 (1); 1.07(2), 10 (4). In 1,
the crystal packing is of interest, the molecules packing in
layers normal to c*, with difference map residues modeled
as water molecules located on 2-axes in between, i.e., a
“hemihydrate”.
Crystal Structure of 1, 2, and 4. The metal atom
environments in complexes 1 (Figure 2) and 4 (Figure 4)
closely resemble each other, silver being in a distorted
tetrahedral array, with P-Ag-P angles of 120.9(1)° and
121.4(1)°, respectively, and two sets of Ag-O (1, 2.349(7)
and 2.498(6) Å; 4, 2.354(8) and 2.42(1) Å) and Ag-P (1,
2.475(3) and 2.465(3) Å; 4, 2.457(3) and 2.462(3) Å) bond
distances. They differ radically from the environment of 2
(17) (a) O’Connell, M. J.; Ramsay, C. G.; Steel, P. J. Aust. J. Chem. 1985,
38, 401-409. (b) Uzoukwu, A. B.; Al-Juaid, S. S.; Hitchcock, P. B.;
Smith, J. D. Polyhedron 1993, 12, 2719-2724. (c) Akama, Y.; Shiro,
M.; Ueda, T.; Kajitani, M. Acta Crystallogr. 1995, C51, 1310-1314.
(d) Guard, J. A. M.; Steel, P. J. Aust. J. Chem. 1994, 47, 1453-1459.
(e) Holzer, W.; Mereiter, K.; Plagens, B. Heterocycles 1999, 50, 799-
818.
(18) Bowmaker, G. A.; Brown, C. L.; Hart, R. D.; Healy, P. C.; Rickard,
C. E. F.; White, A. H. J. Chem. Soc., Dalton Trans. 1999, 881-890.
1158 Inorganic Chemistry, Vol. 41, No. 5, 2002

Ag(I) DeriWatiWes with Nonfluorinated â-Diketones
Table 2. R3P Phosphine Ligand Conformation Descriptors: Torsion
environment (Figure 6), here AgS2P, with three unidentate
ligands, seemingly, further, the only structurally defined
complex of this type at all, Ag-P ) 2.4387(4) Å, Ag-S )
2.4866(5), 2.5003(4) Å, the latter two comparable with
Ag-S distances in [Ag(hfac)(SEt2)] (2.47(9) Å)4g and in
[Ag(hfac)(C4H8OS)2] (2.468(2) and 2.473(2) Å),4e with
P-Ag-S ) 118.25(1)°, 122.50(1)° and S-Ag-S ) 116.13-
(1)°, sum 356.9°, quasi-planar. This is despite the avail-
ability of other ligands, most notably the anion, with which
it cocrystallizes, and, presumably, it is of inferior donor
capacity compared to the phosphorus and sulfur donors, cap-
able of filling a fourth coordination site, either as unidentate
or chelate. For the AgS2P array, ø2(plane) is 4.3 × 104, with
deviations δAg,P,S,S ) 0.190(1), -0.066(1), -0.061(1), and
-0.063(1) Å, a slight but significant pyramidal distor-
tion; Ag-S-C are 109.46(5)° and 105.66(4)°, the Hmimt
C3N2S ligand planes having dihedral angles of 42.97(4)°
and 81.28(5)° to the coordination plane. Trisubstituted
phosphine conformational descriptors, given for all com-
plexes in Table 2, show the present PPh3 ligand to have the
common quasi-3 symmetry in this compound. Although not
coordinated, the anion nevertheless interacts strongly with
the cation, the totality perhaps best viewed as a neutral ion
pair, the deprotonated oxygen pendant from the ring hy-
drogen-bonded strongly to both imidazole ring N hydrogens,
presumably influencing the overall cation conformation,
O(5)‚‚‚H,N(23);H,N(33) ) 1.84(3), 2.696(2); 1.83(2), 2.658-
(2) Å (Figure 6). The non-hydrogen system of the anion is
rather more distorted from planarity than in the acid ligand
Q3H, with, interestingly, the carbonyl group now disposed
quasi-trans to the pendant ring oxygen, as is also the case
in 15 (see below).
Crystal Structure of 15. Yet another coordination mode
for anionic Q-type ligands is found in the 1:1 adduct formed
with “trimen”, derivative 15 (Figure 7), the complex again
containing four-coordinate silver(I), with two coordination
sites occupied by the N,N′-bidentate trimen. The other two
coordination sites are filled by a pair of Q1 donor atoms,
this time from successive ligands which bridge successive
silver atoms into a one-dimensional polymer, the donor atoms
being the unsubstituted pyrazole nitrogen and the (deproto-
nated) O(5), any potential chelation in concert with O(41)
being obviated by the disposition of the latter in a trans
orientation, as in 10, the ligand approximately planar. The
two Ag-N(diamine) distances differ quite markedly,
Ag-N(1′) (carrying Me2) ) 2.421(3) Å and Ag-N(2′)
(monomethylated) ) 2.258(3) Å. Ag-N(2) (Q1) is 2.155(2)
Å and Ag-O(5) 2.969(2) Å; i.e., the coordination of the Q1
ligand here is dominated by Ag-N rather than Ag-O
interactions. Indeed, the sum of the N-Ag-N angles (N(2)-
Ag-N(1′,2′) ) 134.3(1)°, 146.6(1)°; N(1′)-Ag-N(2′) (the
diamine “bite” angle) ) 78.2(1)°) is 359.1°, although the
Ag-N(2) distance is similarly short or linearly opposed and
the array should presumably be best considered as a trigonal
planar AgN3 ()(N2)AgN) array. O(5)-Ag-N(2,1′,2′) are
112.44(8)°, 87.19(9)°, and 69.85(9)°, as appropriate to an
approach of the oxygen of the next Q1 ligand quasi-normal
to the AgN3 plane.
Angles (deg)a
compd/ligand
n ) 1
n ) 2
n ) 3
1/1
1/2
2/1
62.7(10)
24.6(9)
-3.8(10)
13.1(1)
56.8(1)
-65.1(1)
56.2(1)
-65.8(1)
-25.1(10)
-23.3(11)
42.9(1)
24.2(9)
66.8(9)
67.3(1)
-43.6(1)
-174.0(1)
-26.2(2)
-153.1(1)
-0.4(1)
-163.4(1)
-59.1(1)
173.5(1)
-66.5(11)
-69.1(15)
61.2(1)
2/2
4/1
4/2
10
-14.6(10)
36.4(2)
11
20.1(1)
63.9(1)
23.9(1)
a Values are given for rings n ) 1-3, for the angles Ag-P-C(n1)-
C(2/6) (whichever acute; both values for compound 2 (R ) cy)).
Table 3. Selected Geometries: Mononuclear AgQR:PR3 (1:2)
QR/PR3 (compd)
Q1/PPh3 (1)
Q1/PCy3 (2)
Q2/PPh3 (4)
Distances (Å)
Ag-P(1)
Ag-P(2)
Ag-O(41)
Ag-O(5)
2.475(3)
2.465(3)
2.498(6)
2.349(7)
2.4342(6)
2.3992(5)
2.473(1)
2.391(1)
2.457(3)
2.462(3)
2.42(1)
2.354(8)
Angles (degrees)
120.9(1)
114.3(2)
114.0(2)
92.1(2)
P(1)-Ag-P(2)
P(1)-Ag-O(41)
P(1)-Ag-O(5)
P(2)-Ag-O(41)
P(2)-Ag-O(5)
O(41)-Ag-O(5)
142.12(1)
103.63(3)
88.13(4)
107.12(3)
120.34(4)
75.91(5)
121.4(1)
110.8(3)
114.9(3)
91.5(2)
123.4(2)
73.6(4)
124.3(2)
73.0(2)
Crystal Structure of 10. The other phosphine ligand
complex of 1:1 R3P:AgQ stoichiometry, devoid of other
(potential) coligands, is complex 10 (Figure 5). Despite this,
the coordination number of the silver is 4, achieved by virtue
of the complex being a centrosymmetric dimer, by way of
the Q1 ligands bridging pairs of silver atoms through an O,O′-
chelate array at one end and the unsubstituted pz ring
nitrogen at the other:
O,O′-Q1-N
(o-tol3P)Ag
Ag(Po-tol3)
1
{
}
[
]
N-Q -O,O′
Ag-P,O(41′,5′),N(2) being 2.3715(5), 2.325(1), 2.368(1),
and 2.450(1) Å, with P-Ag-O(41′,5′),N(2) all enlarged well
above the tetrahedral norm, 127.85(3)°, 128.98(3)°, and
121.75(3)°, N(2)-Ag-O(41′,5′) being 98.87(4) and 88.17-
(4) Å, and the O(41′)-Ag-O(5′) “bite” angle being 78.58-
(4)°, accommodating any crowding as a consequence of the
large phosphine ligand “cone angle”. Previously the acylpyra-
zolonate ligands have been found to show a similar η3-
coordinating behavior only with lead.11 The non-hydrogen
skeleton of the ligand here is quasi-planar, except for the
pendant ring 41, the two centrosymmetrically related bridging
planes obligate parallel; the two silver atoms deviate
considerably from the bridging OC3N2CO planes by 1.149-
(2) and 2.102(1) Å (coordinated by O,O and N, respectively).
The molecules pack in layers normal to c.
Crystal Structure of 11. The ionic compound 11, of the
form [Ag(Hmimt)2(Ph3P)]+(Q1)-, is of interest from a
number of aspects. It is the only complex of the present array
in which the silver atom lies in a mononuclear tricoordinate
Inorganic Chemistry, Vol. 41, No. 5, 2002 1159

Cingolani et al.
Table 4. Crystal/Refinement Data
HQ3
HQ3
1
2
4
10
11
15
[Ag(Q1)(P h3P)2]‚ [Ag(Q1)(C y3P)2]‚ [Ag(Q2)(P h3P)2]
[Ag(Q1)(o-t ol3P)]2 [{Ag(Ph3 P)-
[Ag(Q1)(tr imen)](|)
1/2H2O
Me2CO
(Hmimt )2}Q1]
empirical formula
Mr
C
216.2
12H12N2 O2
C53H44Ag N2O2.5P2 C56H85Ag N2O3P2 C48H38Ag F3N2O2P2 C76H68Ag2 N4O4P2 C43H40Ag N6O2PS2 C22H27Ag N4O2
918.8
1004.1
901.7
1379.1
875.8
487.4
T (K)
ca. 295
ca. 295
ca. 153
triclinic
P1h (no. 2)
10.4655(9)
12.079(1)
22.804(2)
104.872(2)
95.180(2)
104.144(2)
2665
ca. 298
triclinic
P1h (no. 2)
10.672(2)
10.710(2)
18.713(3)
87.573(2)
80.972(2)
81.734(2)
2090
ca. 153
ca. 153
triclinic
P1h (no. 2)
11.553(1)
11.943(1)
15.479(2)
74.829(2)
76.094(2)
78.185(2)
1978
ca. 153
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
δ (deg)
V (Å3)
monoclinic
C2/c (no. 15)
17.981(6)
5.0641(4)
24.271(6)
monoclinic
C2/c (no. 15)
16.193(8)
13.859(7)
39.306(7)
monoclinic
P21/c (no. 14)
11.8221(6)
13.2601(6)
20.5141(10)
monoclinic
P21/c (no. 14)
7.982(1)
12.299(2)
21.507(3)
99.67(2)
100.02(3)
91.758(1)
95.119(3)
2179
8
1.318
0.9
8686
8
1.405
5.8
3214
2103
4
1.539
9.8
Z
2
2
2 dimers
1.425
7.1
2
Dc (g cm-3
)
1.251
4.8
1.432
6.1
1.470
7.0
µ (cm-1
)
specimen (mm)
‘T’ min, max
2θ max (deg)
Ntotal
0.90 × 0.60 × 0.40 0.25 × 0.38 × 0.12 0.35 × 0.25 × 0.20 0.22 × 0.05 × 0.04 0.3 × 0.12 × 0.12 0.4 × 0.35 × 0.30 0.15 × 0.13 × 0.11
n/a
0.87, 0.95
50
0.72, 0.80
75
0.45, 0.60
50
0.75, 0.86
75
0.73, 0.85
75
0.72, 0.86
75
50
5894
13300
52246
17927
65629
37475
43851
N (Rint
No
)
1900 (0.026)
1610
0.042
0.057
7357 (0.12)
2895
0.054
0.062
0.59(2)
constrained
26492 (0.027)
20455
0.041
7481 (0.041)
2950
0.068
0.063
0.85(3)
constrained
16774 (0.040)
11517
0.035
0.038
1.43(9)
refined
19223 (0.022)
15850
0.031
0.039
1.14(4)
refined
11051 (0.10)
4722
0.047
0.044
1.7(1)
Ra
b
Rw
0.046
|∆F max (e Å-3)| 0.16(1)
1.45(7)
(x, y, z, Uiso
)
refined
refinedc
constrained
H
2
2
2
a R ) ∑||Fo| - |Fc||/∑|Fo|. b Rw ) {[∑w(|Fo| - |Fc| )2]/[∑w(|Fo| )2]}1/2
.
c Acetone solvent excepted.
Considering those ligand geometries offering adequate
precision in overview (Table 1), the most pronounced
differences are to be found in association with the protonated
parent, Q3H, compared to the remainder, such differences
as are found appearing more attributable to the presence of
the hydrogen rather than the substitution of the phenyl (as
found in the remainder) by the methyl. Compared with the
simple and more complex (cis) chelate systems of 2 and 10,
the O‚‚‚O distance is diminished, presumably because of the
hydrogen bond and the small effective size of the hydrogen
compared to silver. Other distances are remarkably similar
except about O(5), consistent with incorporation of the bond
to the latter into the conjugated system as a consequence of
deprotonation. The most substantial angular changes are
found in the vicinity also, within the “chelate” ring, as a
consequence of change in the “chelated” entity. Passage from
the simple chelate mode found in 2 to the chelate/bridging
mode of 10 introduces no further nontrivial change into the
bonding parameters of the ligand.
phine-silver [Ag2(hfac)2(dmpm)2].4d However, derivative 15
is the first structurally characterized with an acylpyrazolonate
acting as bridging O,N-donor.
Conclusion
We have synthesized and characterized 16 novel silver(I)
derivatives of acylpyrazolonates. Some derivatives are ionic,
and some are neutral mononuclear, dinuclear, or polynuclear
in the solid state, depending on the nature and quantity of
the ancillary donor employed.
Derivatives [Ag(Q)(R3P)2], containing two phosphines
bonded to silver, are mononuclear with a distorted tetrahedral
geometry, with distortions essentially dependent on the cone
angle of R3P. Derivatives containing only one phosphine,
[Ag(Q)(R3P)]2, are dinuclear species, with a bridging Q
ligand acting as O2N-tridentate donor, in contrast with species
such as [Ag(hfac)(Me3P)] that have been found to be
mononuclear.4c The [Ag(Q)(R3P)2] complexes containing two
sterically hindered R3P groups undergo partial dissociation,
and the [Ag(Q)(R3P)]2 complexes dissociate in solution into
the Ag(Q)(R3P) fragments. The acylpyrazolonates can be
displaced from the inner silver coordination sphere in
[Ag(Q)(R3P)2] compounds by excess dppe or Hmimt, af-
fording 1:1 ionic species with [AgP4] and [AgS2P] cores,
respectively. The insoluble [Ag(Q)(dppe)] species is likely
polymeric, as also derivatives of formula [Ag(Q)(trimen)],
where the N2-donor behaves as chelating, with the acylpyra-
zolonate donor bridging two Ag atoms, through one oxygen
and one nitrogen atom. In conclusion the N2-donor trimen
can be used to build up linear silver(I) coordination polymers,
with acylpyrazolonates as blocking anions, able to restrict
polymer dimensionality.
Even more profound changes are found in the angular
geometries in the vicinity of C(4) on passing to the anionic
ligand type, in which the oxygen atoms lie trans, these being
relatively little further affected by passing to the bridging
mode of 15, except with respect to the C(5)-O(5) distance,
where further contraction occurs.
Several crystal structures of silver derivatives have been
previously reported containing bridging â-diketonates, as in
diene-silver [Ag2(hfac)2(cod)2],4a [Ag2(hfac)2(dmcod)2],4h
[{Ag(hfac)}2(nbd)]2,4e [Ag(hfac)]4(SEt2),4f and [Ag(hfac)]2-
(7-ButO-nbd),4i in alkyne-silver [{Ag(hfac)}2(PrnCtCPrn)]2,4g
in polyether-silver [Ag2(hfac)2(diglyme)2] and [Ag2(hfac)-
(O2CCF3)(diglyme)2],4k in polythioether-silver [Ag2(hfac)2-
([9]aneS3)2] and [Ag2(hfac)2([14]aneS3)2],4l and in diphos-
1160 Inorganic Chemistry, Vol. 41, No. 5, 2002

Ag(I) DeriWatiWes with Nonfluorinated â-Diketones
The air and moisture stability of silver acylpyrazolonato
derivatives here reported, in contrast to analogue silver
fluorinated acetylacetonates, may be realized by the unique
property of the ligands Q, where the fused peripheral
pyrazolyl backbone plays an important role, not only in the
bonding formation through the N2 atom, but likely also in
protecting the metal environment, whereas, on the basis of
the results reported, substitution in the acyl fragment of Ph
with Me or CF3 does not seem to deeply influence the
stability of silver compounds.
Acknowledgment. Thanks are due to the University of
Camerino (Italy) and Carima Foundation for financial
support.
Supporting Information Available: Complete analytical and
spectroscopic data for derivatives 5, 6, 7, and 13, X-ray crystal-
lographic files, in CIF format, for the structure determinations of
Q3H, 1, 2, 4, 10, 11, and 15, and a drawing for the crystal structure
of Q3H. This material is available free of charge via the Internet at
the http://pubs.acs.org.
IC0109391
Inorganic Chemistry, Vol. 41, No. 5, 2002 1161