Synthesis of [Ag(NH=CMe2)2]ClO4 and Its Use as a Source of Acetimine. 1. Synthesis of the First Acetimine Rhodium Complexes and the First Crystal Structure of a Diacetonamine Complex

Article abstract of DOI:10.1021/ic035002+

The reaction of AgClO₄ and NH₃ in acetone gave [Ag(NH=CMe₂)₂]ClO₄ (1). The reactions of 1 with [RhCl(diolefin)]₂ or [RhCl(CO)₂]₂ (2:1) gave the bis(acetimine) complexes [Rh(diolefin)(NH=CMe₂) ₂]ClO₄ [diolefin = 1,5 cyclooctadiene = cod (2), norbornadiene = nbd (3)] or [Rh(CO)₂(NH=CMe₂) ₂]ClO₄ (4), respectively. Mono(acetimine) complexes [Rh(diolefin)(NH=CMe₂)(PPh₃)]ClO₄ [diolefin = cod (5), nbd (6)] or [RhCl(diolefin)(NH=CMe₂)] [diolefin = cod (7), nbd (8)] were obtained by reacting 2 or 3 with PPh₃ (1:1) or with Me₄NCl (1:1.1), respectively. The reaction of 4 with PR₃ (R = Ph, To, molar ratio 1:2) led to [Rh(CO)(NH=CMe₂)(PR ₃)₂]ClO₄ [R = Ph (9), C₆H ₄Me-4 = To (10)] while cis-[Rh(CO)(NH=CMe₂) ₂(PPh₃)ClO₄ (11) was isolated from the reaction of 1 with [RhCl(CO)(PPh₃)]₂ (1:1). The crystal structures of 5 and [Ag{H₂NC(Me)₂CH ₂C(O)Me}(PTO₃)]ClO₄ (A), a product obtained in a reaction between NH₃, AgClO₄, and PTO₃, have been determined.

Full text of DOI:10.1021/ic035002+

Inorg. Chem. 2003, 42, 7644−7651
Synthesis of [Ag(NHdCMe2)2]ClO and Its Use as a Source of
4
Acetimine. 1. Synthesis of the First Acetimine Rhodium Complexes and
the First Crystal Structure of a Diacetonamine Complex
,†
,†
Jose´ Vicente,* Mar´ıa-Teresa Chicote,* Rita Guerrero,† Inmaculada Vicente-Herna´ndez,† and
Peter G. Jones‡
Grupo de Qu´ımica Organometa´lica, Departamento de Qu´ımica Inorga´nica, Facultad de Qu´ımica,
UniVersidad de Murcia, Aptdo. 4021, Murcia, 30071 Spain, and Institut fu¨r Anorganische und
Analytische Chemie, Technische UniVersita¨t Braunschweig, Postfach 3329,
38106 Braunschweig, Germany
Received August 25, 2003
The reaction of AgClO and NH in acetone gave [Ag(NHdCMe2)2]ClO (1). The reactions of 1 with [RhCl(diolefin)]2
4
3
4
or [RhCl(CO)2]2 (2:1) gave the bis(acetimine) complexes [Rh(diolefin)(NHdCMe ) ]ClO [diolefin ) 1,5 cyclooctadiene
2 2
4
) cod (2), norbornadiene ) nbd (3)] or [Rh(CO)2(NHdCMe2)2]ClO (4), respectively. Mono(acetimine) complexes
4
[Rh(diolefin)(NHdCMe2)(PPh3)]ClO [diolefin ) cod (5), nbd (6)] or [RhCl(diolefin)(NHdCMe2)] [diolefin ) cod (7),
4
nbd (8)] were obtained by reacting 2 or 3 with PPh3 (1:1) or with Me4NCl (1:1.1), respectively. The reaction of 4
with PR (R ) Ph, To, molar ratio 1:2) led to [Rh(CO)(NHdCMe2)(PR ) ]ClO [R ) Ph (9), C H Me-4 ) To (10)]
3
3 2
4
6 4
while cis-[Rh(CO)(NHdCMe2)2(PPh3)]ClO (11) was isolated from the reaction of 1 with [RhCl(CO)(PPh3)]2 (1:1).
4
The crystal structures of 5 and [Ag{H NC(Me)2CH C(O)Me}(PTo )]ClO (A), a product obtained in a reaction between
2
2
3
4
NH , AgClO , and PTo3, have been determined.
3
4
Chart 1. Condensation Products of NH3 and Acetone
Introduction
The participation of imines in functional group transfor-
mations, carbon-carbon bond formation, and ring construc-
tion processes1 makes them important intermediates in
synthesis. Unlike N-substituted imines, which are generally
stable and serve as ligands in many metal complexes,2 the
NH aldimines or ketimines are, with the exception of
diarylketimines, unstable compounds that need to be trapped
with various reagents.1 In particular, NHdCMe2 (acetimine)
is a reactive compound that decomposes after short periods
of storage, even at 0 °C, to give 2,2,4,4,6-pentamethyl-
2,3,4,5-tetrahydropyrimidine (acetonine, see Chart 1) with
NH3 loss.3 Acetimine has been prepared from R-aminonitriles
† Grupo de Qu´ımica Organometa´lica. E-mail: jvs@um.es (J.V.);
mch@um.es (M.T.C); rgs@um.es (R.G.); inmavh@um.es (I.V.-H.). Web
address: http://www.um.es/gqo/.
‡ Institut fu¨r Anorganische und Analytische Chemie. E-mail: p.jones@tu-
bs.de.
(1) Robertson, G. M. In ComprehensiVe Organic Functional Group
Transformations; Katritzky, A. R., Meth-Cohn, O., Rees, C. W., Eds.;
Pergamon: Oxford, U.K., 1995; Vol. 3.
(2) Mehrotra, R. C. In ComprehensiVe Coordination Chemistry; Wilkinson,
G., Gillard, R. D., McCleverty, J. A., Eds.; Pergamon: Oxford, U.K.,
1987; Vol. 2.
and dicyclohexylcarbodiimide3 and also from acetone and
ammonia in high temperature and pressure processes4
(3) Findeisen, K.; Heitzer, H.; Dehnicke, K. Synthesis 1981, 702.
7644 Inorganic Chemistry, Vol. 42, No. 23, 2003
10.1021/ic035002+ CCC: $25.00 © 2003 American Chemical Society
Published on Web 10/24/2003

Synthesis of [Ag(NHdCMe2)2]ClO4
catalyzed by NH4Cl5 or HZSM-5 zeolite. However, it has
long been known that the reactions of acetone and ammonia,
using different stoichiometric ratios and reaction conditions,
lead to mixtures of a variety of condensation products (see
Chart 1), including acetimine (A), MeC(O)CH2C(Me)2NH2
(diacetonamine, B),6 2,2,6,6-tetramethyl-4-piperidone (tri-
acetonamine, C),6,7 acetonine (D),7 and 1,9-diaza-2,2,8,8,10-
hexamethylspiro[5.5]-undecan-4-one (E).7 Many patents have
been devoted to the study of such reactions since some of
these condensation products have found application as
intermediates for the synthesis of nitroxides, oxoammonium
salts, pharmaceutical products, pesticides, and photostabi-
lizers for polymers.8-13
The mentioned difficulties in the preparation and handling
of acetimine account for the scarcity of complexes with this
ligand. In fact, acetimine itself has not been used in the
various syntheses of metal-acetimino complexes reported
so far,14-29 namely (i) the reaction of acetone with ammine
complexes of Cr0, Mo0, W0, FeII, MnI,14 AuI,15,16 OsII;17 (ii)
the reactions in acetone between ammonium salts and
complexes containing acetylacetonato ligands (AuI),16 or
hydrido ligands (RuII);18 (iii) the reactions of carbene- or
THF-carbonyl complexes of Cr0,19 or W0,20 with dimeth-
ylketoxime; (iv) the reactions in acetone between PdII
complexes and NH3(aq);21 (v) the redox conversion into
acetimine of 2,3-dimethyl-2,3-diaminobutane22 or isopropyl-
amine23 ligands in RuII complexes or acetonitrile in one W0
complex;24 (vi) the redox transmetalation of imine from an
acetimine Cr0 complex and CuBr2 to give an acetimino CuI
complex;14 (vii) the hydrogen transfer reaction in an alkenyl/
azavinylidene OsIV complex to give a vinylidene/acetimine
OsII complex;25 (viii) the thermal decomposition of amino-
siliceniotrichloroaluminates (R2SiNCMe3‚AlCl3);26 (ix) the
reaction of a Ni0 dinitrogen complex with N-allyldimeth-
yliminium tetraphenylborate to give a NiII acetimine com-
plex;27 (x) the reactions of Na2[M2(CO)10] (M ) Cr, W) with
2-Br-2-nitrosopropane;28 or (xi) the reaction of [Bu4N]-
[Pt(C6F5)3(azaH)] (aza )7-azaindole) with Ag2CO3 and
NH3(aq) in acetone to give [Bu4N][(C6F5)3Pt(µ-aza)Ag(NHd
CMe2)].29 In conclusion, although nearly as many different
synthetic methods as acetimine complexes have been de-
scribed, none of them have proven to be of general
applicability.
A different type of NH-imines, R(R′O)CdNH, R(R′NH)Cd
NH, and R{R′C(O)(Ph3Pd)C}CdNH, also unstable in the
free state, have been obtained by nucleophilic additions to
metal-bound nitriles.30-34
In this paper, we report the synthesis of [Ag(NHdCMe2)2]-
ClO4 which could provide (i) a general method for preparing
[M]-acetimine complexes by reacting it with the appropriate
[M]-X (X ) Cl, Br, I, AcO, etc.) derivatives and (ii) a
source of the free ligand. In an attempt to explore the
application of this complex in synthesis of acetimine
complexes, we have used it to prepare the first RhI-
acetimine complexes.
(4) Xu, T.; Zhang, J.; Haw, J. F. J. Am. Chem. Soc. 1995, 117, 3171.
(5) Verardo, G.; Giumanini, A. G.; Strazzolini, P.; Poiana, M. Synth.
Commun. 1988, 18, 1501.
(6) Bradbury, R. B.; Hancox, N. C.; Hatt, H. H. J. Chem. Soc. 1947, 1394.
(7) Murayama, K.; Morimura, S.; Amakasu, O.; Toda, T.; Yamao, E.
Nippon Kagaku Zasshi 1969, 90, 296; Chem. Abstr. 1969, 70, 324.
(8) Sasaki, K.; Oikawa, M.; Myake, K. (Sumitomo Chemical Co.) Patent
JP 07,291,931; Chem. Abstr. 1996, 124, 202290j.
(9) Fukuda, Y. (Kyowa Yuka Kk) Patent JP 05,117,242; Chem. Abstr.
1993, 119, 180817d.
(10) Inaba, M.; Inui, Y. (Mitsubishi Petrochemical Co., Ltd.) Patent JP
01,233,271; Chem. Abstr. 1990, 112, 55627w.
(11) Kinishi, R.; Kasagi, M. (Yoshitomi Pharmaceutical Industries, Ltd.)
Patent JP 62,132,859; Chem. Abstr. 1987, 107, 198104f.
(12) Sakanashi, K.; Azaki, Y. (Yoshitomi Pharmaceutical Industries, Ltd.)
Patent JP 62,167,763; Chem. Abstr. 1988, 108, 150314t.
(13) Ma, Z.; Huang, Q.; Bobbit, J. M. J. Org. Chem. 1993, 58, 4837.
(14) Sellmann, D.; Thallmair, E. J. Organomet. Chem. 1979, 164, 337.
(15) Vicente, J.; Chicote, M.-T.; Abrisqueta, M.-D.; Guerrero, R.; Jones,
P. G. Angew. Chem., Int. Ed. Engl. 1997, 36, 1203.
(16) Vicente, J.; Chicote, M.-T.; Guerrero, R.; Saura-Llamas, I. M.; Jones,
P. G.; Ram´ırez de Arellano, M. C. Chem. Eur. J. 2001, 7, 638.
(17) Harman, W. D.; Taube, H. Inorg. Chem. 1988, 27, 3261.
(18) Rappert, T.; Yamamoto, A. Chem. Lett. 1994, 2211.
(19) Fischer, E. O.; Knauss, L. Chem. Ber. 1970, 103, 1262.
(20) Czarkie, D.; Shvo, Y. J. Organomet. Chem. 1985, 280, 123.
(21) Ruiz, J.; Rodr´ıguez, V.; Cutillas, N.; Lo´pez, G. Organometallics 2002,
21, 4912.
Experimental Section
IR spectroscopy, elemental analyses, and melting point deter-
minations were carried out as described elsewhere.16 Molar
conductivities were measured on ca. 5 × 10-4 M acetone solutions
with a Crison Micro CM2200 conductimeter. The NMR spectra
were recorded on Varian Unity 300 MHz, Bruker Avance 200 MHz,
or Bruker Avance 400 MHz spectrometers. Chemical shifts are
referred to TMS (1H and 13C{1H}) and H3PO4 (31P{1H}). Unless
otherwise stated, all reactions were carried out at room temperature
and without special precautions against moisture. CH2Cl2, acetone,
and Et2O were distilled before use from CaH2, KMnO4, and Na/
benzophenone, respectively. Other solvents [n-pentane (Baker) and
n-hexane (Scharlau)] and reagents [AgClO4 (Riedel-de Ha¨en),
anhydrous NH3 (Carburos Meta´licos), NaH (60%, dispersion in
mineral oil), PPh3, PTo3 (C6H4Me-4 ) To), Me4NCl, cod, nbd
(Fluka)] were obtained from commercial sources and used as
received. The complexes [RhCl(nbd)]2,35 [RhCl(CO)2]2,36 [RhCl-
39
(cod)]2,37 [RhCl(CO)(PPh3)2],38 and [RhCl(CO)(PPh3)]2 were
prepared according to literature methods.
(22) Wong, K.-Y.; Che, C.-M.; Li, C.-K.; Chiu, C.-K.; Zhou, Z.-Y.; Mak,
T. C. W. J. Chem. Soc., Chem. Commun. 1992, 754.
(23) Adcock, P. A.; Keene, F. R.; Smythe, R. S.; Snow, M. R. Inorg. Chem.
1984, 23, 2336.
(24) Yeh, W. Y.; Ting, C. S.; Peng, S. M.; Lee, G. H. Organometallics
1995, 14, 1417.
(30) Kukushkin, V. Y.; Pombeiro, A. J. L. Chem. ReV. 2002, 102, 1771.
(31) Michelin, R. A.; Mozzon, M.; Bertani, R. Coord. Chem. ReV. 1996,
147, 299.
(32) Bokach, N. A.; Kukushkin, V. Y.; Haukka, M.; Dasilva, J.; Pombeiro,
A. J. L. Inorg. Chem. 2003, 42, 3602.
(25) Castarlenas, R.; Esteruelas, M. A.; On˜ate, E. Organometallics 2000,
19, 5454.
(26) Klingebiel, U.; Noltemeyer, M.; Schmidt, H.-G.; Schmidt-Ba¨se, D.
Chem. Ber. 1997, 130, 753.
(33) Vicente, J.; Chicote, M. T.; Lagunas, M. C.; Jones, P. G. Inorg. Chem.
1995, 34, 5441.
(34) Vicente, J.; Chicote, M. T.; Beswick, M. A.; Ram´ırez de Arellano,
M. C. Inorg. Chem. 1996, 35, 6592.
(27) Aresta, M.; Quaranta, E.; Dibenedetto, A.; Giannoccaro, P.; Tommasi,
I.; Lanfranchi, M.; Tiripicchio, A. Organometallics 1997, 16, 834.
(28) King, R. B.; Douglas, W. M. Inorg. Chem. 1974, 13, 1339.
(29) Fornie´s, J.; Casas, J. M.; Mart´ın, A.; Rueda, A. J. Organometallics
2002, 21, 4560.
(35) Abel, E. W.; Bennett, M. A.; Wilkinson, G. J. Chem. Soc. 1959, 3178.
(36) Cramer, R. Inorg. Synth. 1974, 15, 14.
(37) Giordano, G.; Crabtree, R. H. Inorg. Synth. 1979, 19, 218.
(38) McCleverty, J. A.; Wilkinson, G. Inorg. Synth. 1966, 8, 214.
(39) Maisonnat, A.; Kalck, P.; Poilblanc, R. Inorg. Chem. 1974, 13, 661.
Inorganic Chemistry, Vol. 42, No. 23, 2003 7645

Vicente et al.
Warning! Perchlorate salts of organic cations may be explosive.
Preparations on a larger scale than that reported herein should be
avoided. Danger! Ammonia solutions of silver salts produce
explosive compounds (silver fulminate and fulminating silver) upon
storing more than 2 h.
for C14H26ClN2O4Rh: C, 39.59; H, 6.17; N, 6.60. Found: C, 39.54;
H, 6.51; N, 6.62.
Compound 3. Yield: 175 mg, 87%. Dec point 124 °C. 1H NMR
(300 MHz, CDCl3): δ ) 1.28 (s, 2 H, CH2), 2.12 (s, 6 H, Me),
2.40 (s, 6 H, Me), 3.89 (s, 2 H, CH), 4.10 (s, 4 H, CHdCH), 8.68
(br, 2 H, NH). 13C{1H} NMR (50 MHz, CDCl3): δ ) 27.93 (s,
[Ag(NHdCMe2)2]ClO4 (1). AgClO4 (512 mg, 2.47 mmol) was
dissolved in acetone (70 mL) and anhydrous NH3 bubbled through
the solution for 2 min. The reaction mixture was stirred for 30 min,
the solution was concentrated to 2 mL, and Et2O (25 mL) was added
to give a colorless solid which was filtered off. The product was
recrystalized from CH2Cl2/Et2O (2:30 mL). The resulting mixture
(729 mg) was placed in a flask with HNa (134 mg, 3.35 mmol)
under a nitrogen atmosphere. Dry CH2Cl2 (120 mL) was added,
and the reaction stirred for 75 min under a nitrogen atmosphere.
The mixture was filtered in the air through Celite and concentrated
to 2 mL. Upon adding Et2O (40 mL), a colorless solid precipitated,
which was filtered and air-dried to give 1. Yield: 559 mg, 1.74
mmol (70%). Mp 103 °C. 1H NMR (200 MHz, CDCl3): δ ) 2.27
(s, 12 H, Me), 9.03 (s, br, 2 H, NH). 1H NMR (400 MHz, acetone-
d6, 20 °C): δ ) 2.30 (s, 12 H, Me), 9.56 (s, br, 2 H, NH).1H NMR
(400 MHz, acetone-d6, -60 °C): δ ) 2.25 (s, 6 H, Me), 2.28 (s,
6 H, Me), 9.78 (br, 2 H, NH). 13C{1H} NMR (50 MHz, CDCl3):
δ ) 28.47 (s, Me), 29.91 (s, Me), 188.20 (s, CdN). IR (Nujol): ν
2
Me), 28.49 (s, Me), 51.21 (d, CH, JC-Rh ) 2.56 Hz), 60.43 (d,
1
3
CHdCH, JC-Rh ) 9.87 Hz), 62.70 (d, CH2, JC-Rh ) 5.85 Hz),
184.81 (s, CdN). IR (Nujol): ν ) 3254 (s) (NH), 1656 (m) (CdN)
cm-1. ΛM: 154 Ω-1 cm2 mol-1. Anal. Calcd for C13H22ClN2O4Rh:
C, 38.21; H, 5.43; N, 6.85. Found: C, 37.96; H, 5.69; N, 6.75.
cis-[Rh(CO)2(NHdCMe2)2]ClO4 (4). [RhCl(CO)2]2 (60 mg,
0.16 mmol) was added to a solution of 1 (120 mg, 0.31 mmol) in
CH2Cl2 (20 mL). AgCl immediately precipitated. The resulting
suspension was stirred for 10 min, filtered through a short pad of
Celite, and then concentrated (1 mL). When Et2O was added (20
mL), a cloudy solid precipitated, which was filtered and air-dried
to give 4 as a pale yellow solid. Yield: 93 mg, 80%. Dec point
131 °C. 1H NMR (300 MHz, CDCl3): δ ) 2.33 (s, 3 H, Me), 2.43
(s, 3 H, Me), 9.14 (br, 1 H, NH). 13C{1H} NMR (300 MHz,
CDCl3): δ ) 28.77 (s, Me), 29.63 (s, Me), 183.31 (d, CO, 1JC-Rh
) 66.7 Hz), 190.94 (s, CdN). IR (Nujol): ν ) 3262 (s) (NH),
2092 (s), 2026 (s) (CdO), 1666 (s) (CdN) cm-1. ΛM: 147 Ω-1
cm2 mol-1. Anal. Calcd for C8H14ClN2O6Rh: C, 25.79; H, 3.79;
N, 7.52. Found: C, 25.85; H, 3.85; N, 7.52.
) 3294 (s) (NH), 1662 (s) (CdN) cm-1. ΛM: 156 Ω-1 cm2 mol-1
.
Anal. Calcd for C6H14AgClN2O4: C, 22.41; H, 4.39; N, 8.71.
Found: C, 21.94; H, 4.52; N, 8.71.
[Rh(cod)(NHdCMe2)(PPh3)]ClO4 (5). A solution of PPh3 (50
mg, 0.19 mmol) in CH2Cl2 (5 mL) was added dropwise to a yellow
solution of 2 (80 mg, 0.19 mmol). The resulting orange-yellow
solution was stirred for 3 h and then concentrated to 1 mL. Upon
adding Et2O (20 mL), a solid precipitated. The suspension was
filtered and the solid washed with Et2O (2 × 3 mL) and air-dried
to give 5 as a bright yellow solid. Yield: 108 mg, 91%. Dec point
163 °C. 1H NMR (400 MHz, CDCl3): δ ) 1.78 (s, 3 H, Me), 1.79
(s, 3 H, Me), 2.07 (m, 2 H, CH2), 2.14 (m, 2 H, CH2), 2.44 (m, 2
H, CH2), 2.54 (m, 2 H, CH2), 3.60 (s, 2 H, CH), 5.19 (s, 2 H, CH),
5.30 (s, 2 H, CH2Cl2), 7.48-7.65 (m, 15 H, Ph), 9.47 (br, 1 H,
NH). 13C{1H} NMR (50 MHz, CDCl3): δ ) 27.90 (d, Me, 3JC-Rh
) 1.46 Hz), 28.25 (s, Me), 29.01 (d, CH2, 2JC-Rh ) 1.83 Hz), 31.69
[Ag{H2NC(Me)2CH2C(O)Me}(PTo3)]ClO4 (A). Anhydrous
NH3 was bubbled for 2 min through an acetone (20 mL) solution
of AgClO4 (200 mg, 0.96 mmol). The solution was stirred for 5
min and evaporated and the residue dissolved in acetone (20 mL).
MgSO4 was added, and the suspension was stirred for 7 days and
filtered and the filtrate concentrated to dryness. A colorless oil was
obtained (141 mg) which was dissolved in acetone (10 mL). A
solution of PTo3 (133 mg, 0.44 mmol) was then added dropwise,
the solution stirred for 10 min and concentrated to 1 mL, and Et2O
(20 mL) added to give a sticky solid (124 mg). Its analytical [Calcd
(%) for C27H34AgClNO5P: C, 51.73; H, 5.47; N, 2.23. Found: C,
53.35; H, 5.75; N, 2.33.] and spectroscopic data show it is A with
some impurities. From this mixture, two crystals of the title
compound grew by the liquid diffusion method (CH2Cl2/Et2O). One
was used to determine its crystal structure by X-ray diffraction
methods, and the other was studied by NMR spectroscopy. 1H NMR
(400 MHz, CDCl3): δ ) 1.36 (s, 6 H, Me), 2.14 (s, 3 H, Me),
2.39 (s, 9 H, Me), 2.75 (s, 2 H, CH2), 3.86 (br, 2 H, NH2), 7.24-
7.36 (AA′BB′, 12 H, C6H4). 31P{1H} NMR (162 MHz, CDCl3): δ
) 14.18 (dd, J109Ag-P ) 724, J107Ag-P ) 631 Hz).
2
1
(d, CH2, JC-Rh ) 2.56 Hz), 80.04 (d, CH, JC-Rh ) 11.34 Hz),
1
2
102.70 (dd, CH, JC-Rh ) 10.6 Hz, JC-P ) 7.68 Hz), 128.88 (d,
4
1
p-Ph, JC-P ) 9.88 Hz), 129.68 (d, ipso-Ph, JC-P ) 42.42 Hz),
130.75 (d, m-Ph, 3JC-P ) 2.56 Hz), 133.88 (d, o-Ph, 2JC-P ) 11.34
Hz), 184.81 (d, CdN, JC-Rh ) 1.46 Hz). 31P{1H} (162 MHz,
2
1
CDCl3): δ ) 25.96 (d, PPh3, JP-Rh ) 153 Hz). IR (Nujol): ν )
3242 (m) (NH), 1652 (m) (CdN) cm-1. ΛM: 147 Ω-1 cm2 mol-1
.
Anal. Calcd for C29H34ClNO4PRh‚CH2Cl2: C, 50.41; H, 5.08; N,
1.96. Found: C, 50.64; H, 5.44; N, 2.05.
[Rh(diolefin)(NHdCMe2)2]ClO4 [Diolefin ) cod (2), nbd (3)].
To a solution of [RhCl(diolefin)]2 [diolefin ) cod (92.5 mg, 0.19
mmol), nbd (113 mg, 0.25 mmol)] in CH2Cl2 (30 mL) was added
complex 1 [121 mg, 0.38 mmol or 158 mg, 0.49 mmol, respec-
tively]. AgCl immediately formed. The resulting suspension was
stirred for 30 min and then filtered through a short pad of Celite.
The yellow filtrate was then concentrated (1 mL), and Et2O (30
mL) was added to precipitate a solid, which was stirred for 5 min,
filtered, and air-dried to give 2 (lemon yellow) or 3 (yellow).
Compound 2. Yield: 133 mg, 81%. Dec point 170 °C. 1H NMR
(200 MHz, CDCl3): δ ) 1.87 (m, 4 H, CH2), 2.14 (d, 6 H, Me,
4JH-H ) 0.8 Hz), 2.45 (m, 4 H, CH2), 2.52 (s, 6 H, Me), 4.00 (br,
4 H, CH), 8.92 (br, 2 H, NH). 13C{1H} NMR (75 MHz, CDCl3):
δ ) 28.42 (s, Me), 28.57 (s, Me), 30.42 (s, CH2), 82.52 (d, CH,
1JC-Rh ) 1.65 Hz), 185.18 (s, CdN). IR (Nujol): ν ) 3252 (s)
(NH), 1660 (s) (CdN) cm-1. ΛM: 146 Ω-1 cm2 mol-1. Anal. Calcd
[Rh(nbd)(NHdCMe2)(PPh3)]ClO4 (6). Complex 3 (120 mg,
0.29 mmol) and PPh3 (77 mg, 0.29 mmol) were placed in a flask
under a nitrogen atmosphere. Acetone (20 mL) was added, and the
resulting solution was stirred for 15 min under a nitrogen
atmosphere and then concentrated to 1 mL. Upon the addition of
Et2O under a nitrogen atmosphere, a product precipitated which
was stirred for 5 min, filtered, and air-dried to give 6 as a yellow-
1
orange solid. Yield: 145 mg, 80%. Mp 153 °C. H NMR (200
MHz, CDCl3): δ ) 1.46 (s, 2 H, CH2), 1.88 (s, 6 H, Me), 3.65
(br, 2 H, CHdCH), 3.96 (s, 2 H, CH), 5.38 (br, 2 H, CHdCH),
7.47-7.54 (m, 15 H, Ph), 9.30 (br, 1 H, NH). 1H NMR (400 MHz,
CDCl3, -60 °C): δ ) 1.50 (s, 2 H, CH2), 1.82 (s, 3 H, Me), 1.89
(s, 3 H, Me), 3.68 (s, 2 H, CHdCH), 4.02 (s, 2 H, CH), 5.38 (s, 2
H, CHdCH), 7.52 (m, 15 H, Ph), 9.14 (s, 1 H, NH). 13C{1H} NMR
(75 MHz, CDCl3): δ ) 27.90 (s, Me), 28.37 (s, Me), 52.25 (s,
CH), 62.44 (d, CHdCH, 1JC-Rh ) 8.47 Hz), 65.68 (s, CH2), 84.20
7646 Inorganic Chemistry, Vol. 42, No. 23, 2003

Synthesis of [Ag(NHdCMe2)2]ClO4
(s, CHdCH), 128.92 (d, p-Ph, 4JC-P ) 10.07 Hz), 129.41 (d, ipso-
Ph, 1JC-P ) 42.37 Hz), 130.72 (d, m-Ph, 3JC-P ) 2.12 Hz), 133.49
(d, o-Ph, 2JC-P ) 12.18 Hz), 184.47 (s, CdN). 31P{1H} (81 MHz,
Table 1. Crystal Data for Compounds 5 and A
5
A
formula
crystal size (mm3)
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
C29H34ClNO4PtRh
0.36 × 0.18 × 0.18
monoclinic
P21/c
9.7384(8)
32.027(3)
17.5949(14)
90
93.951(4)
90
5474.6(8)
8
C27H34AgClNO5P
0.30 × 0.12 × 0.08
triclinic
1
CDCl3): δ ) 28.62 (d, PPh3, JP-Rh ) 168 Hz). IR (Nujol): ν )
3222 (m) (NH), 1662 (m) (CdN) cm-1. ΛM: 116 Ω-1 cm2 mol-1
.
Anal. Calcd for C28H30ClNO4PRh: C, 54.78; H, 4.93; N, 2.28.
Found: C, 54.81; H, 5.10; N, 2.50.
P1h
10.1821(8)
12.2233(8)
12.4631(8)
100.159(4)
108.292(4)
96.667(4)
1425.07(17)
2
[RhCl(cod)(NHdCMe2)] (7). Complex 2 (160 mg, 0.37 mmol)
was added to a suspension of Me4NCl (45 mg, 0.41 mmol) in
acetone (80 mL) under a nitrogen atmosphere. The resulting mixture
was stirred for 6 h and then evaporated to dryness. The residue
was extracted with Et2O (7 × 40 mL), the extractions were collected
and filtered through a short pad of Celite, and the filtrate
concentrated (2 mL). At this point, a solid precipitated, which was
filtered and air-dried to give 7 as a yellow solid. Yield: 48 mg,
Z
F
Mr
calcd (Mg m-3
)
1.528
629.90
1.462
626.84
133(2)
644
T (K)
F(000)
133(2)
2592
0.816
1.27 to 30.03
semiempirical from
equivalents
96871
16011
0.0495
1
42%. Dec point 223 °C. H NMR (400 MHz, CDCl3): δ ) 1.80
µ Mo KR (mm-1
θ range (deg)
abs corr
)
0.893
(m, 4 H, CH2), 2.11 (s, 3 H, Me), 2.44 (m, 4 H, CH2), 2.60 (s, 3
H, Me), 3.61 (br, 2 H, CH), 4.56 (br, 2 H, CH), 8.31 (br, 1 H,
NH). 13C{1H} NMR (100 MHz, CDCl3): δ ) 28.01 (s, Me), 29.47
(s, Me), 30.76 (br, CH2), 56.11 (s, CH), 183.95 (s, CdN). IR
(Nujol): ν ) 3186 (m) (NH), 1660 (m) (CdN) cm-1. ΛM: 1 Ω-1
cm2 mol-1. Anal. Calcd for C11H19ClNRh: C, 43.51; H, 6.31; N,
4.61. Found: C, 43.15; H, 6.75; N, 4.75.
1.72 to 30.03
semiempirical from
equivalents
29022
reflns collected
indep reflns
Rint
8301
0.0271
transm
0.928/0.828
16011/29/711
0.0334
0.949/0.836
8301/1/339
0.0267
data/restraints/params
R1 [I > 2σ(I)]
wR2 (all reflns)
[RhCl(nbd)(NHdCMe2)] (8). Complex 3 (132 mg, 0.32 mmol)
was added to a suspension of Me4NCl (39 mg, 0.36 mmol) in
acetone (80 mL) under a nitrogen atmosphere. The resulting mixture
was stirred for 6 h and then evaporated to dryness. The residue
was extracted with CH2Cl2 (15 mL) and the suspension filtered
through a short pad of Celite. The yellow filtrate was evaporated
to dryness, Et2O (3 mL) was added, and the suspension was filtered
off. Recrystallization of the solid from CH2Cl2/Et2O afforded 8 as
0.0902
0.0649
Me), 2.38 (s, 18 H, Me), 7.25-7.28 + 7.45-7.55 (AA′BB′, 24 H,
To), 8.81 (br, 1 H, NH). 13C{1H} NMR (50 MHz, acetone-d6): δ
) 21.29 (s, Me), 27.50 (s, Me), 29.22 (s, Me), 129.13 (vt, ipso-Ph,
N ) 48.3 Hz), 130.44 (vt, m-Ph, N ) 10.6 Hz), 135.01 (vt, o-Ph,
N ) 13.5 Hz), 142.45 (s, p-Ph), 186.58 (t, CdN, 3JC-P ) 2.7 Hz),
1
2
191.48 (dt, CO, JC-Rh ) 65.89, JC-P ) 16.0 Hz). 31P{1H} (200
1
a yellow solid. Yield: 79 mg, 84%. Dec point 115 °C. H NMR
1
MHz, CDCl3): δ ) 30.37 (d, PTo3, JP-Rh ) 127.78 Hz). IR
(300 MHz, CDCl3): δ ) 1.25 (s, 2 H, CH2), 2.06 (s, 3 H, Me),
2.40 (s, 3 H, Me), 3.82 (s, 2 H, CH), 3.99 (s, 4 H, CHdCH), 8.27
(br, 1 H, NH). 13C{1H} NMR (75 MHz, CDCl3): δ ) 27.14 (s,
Me), 29.04 (s, Me), 50.08 (s, CH), 50.11 (s, CH), 61.32 (d, CH2,
3JC-Rh ) 6.36 Hz), 183.00 (s, CdN). IR (Nujol): ν ) 3194 (m)
(NH), 1652 (m) (CdN) cm-1. ΛM: 2 Ω-1 cm2 mol-1. Anal. Calcd
for C10H15ClNRh: C, 41.76; H, 5.26; N, 4.87. Found: C, 41.48;
H, 5.50; N, 4.94.
trans-[Rh(CO)(NHdCMe2)(PR3)2]ClO4 [R ) Ph (9), To (10)].
A solution of complex 4 (50 mg, 0.13 mmol) in CH2Cl2 (10 mL)
was added dropwise (about 15 min) to another containing PR3 (R
) Ph, 70 mg, 0.27 mmol; To, 82 mg, 0.27 mmol) in the same
solvent (5 mL). The yellow solution turned to bright yellow. The
reaction mixture was stirred for 1 h 45 min and filtered through
Celite and the filtrate concentrated (1 mL). Upon adding Et2O (20
mL), a yellow solid precipitated, which was stirred for 5 min,
filtered, and air-dried to give 9 (R ) Ph) or 10 (R ) To) as bright
yellow solids.
(Nujol): ν ) 3236 (m) (NH), 1994 (s) (CdO), 1660 (m) (CdN)
cm-1. ΛM: 128 Ω-1 cm2 mol-1. Anal. Calcd for C46H49ClNO5P2-
Rh‚H2O: C, 60.43; H, 5.62; N, 1.53. Found: C, 60.63; H, 5.83;
N, 1.82.
cis-[Rh(CO)(NHdCMe2)2(PPh3)]ClO4 (11). [RhCl(CO)(PPh3)]2
(200 mg, 0.23 mmol) was added to a solution of 1 (150 mg, 0.47
mmol) in CH2Cl2 (20 mL). AgCl immediately formed. The
suspension was stirred for 5 min and then filtered through a short
pad of Celite. The yellow filtrate was then concentrated to 1 mL,
and Et2O (25 mL) was added to precipitate a pale yellow solid,
which was stirred for 10 min, filtered, and air-dried to give 11 as
1
a pale yellow solid. Yield: 260 mg, 93%. Mp 140 °C. H NMR
(400 MHz, CDCl3): δ ) 1.72 (s, 3 H, Me), 1.83 (s, 3 H, Me),
4
2.29 (d, 3 H, Me, JH-H ) 1.1 Hz), 2.47 (s, 3 H, Me), 7.42-7.64
(m, 15 H, Ph), 8.60 (s, 1 H, NH), 9.49 (s, 1 H, NH). 13C{1H}
NMR: too unstable to be recorded. 31P{1H} (162 MHz, CDCl3):
1
δ ) 44.19 (d, PPh3, JP-Rh ) 152 Hz). IR (Nujol): ν ) 3284 (s)
(NH), 1988 (CdO) (vs), 1662 (CdN) (s) cm-1. ΛM: 148 Ω-1 cm2
mol-1. Anal. Calcd for C25H29ClN2O5PRh: C, 49.48; H, 4.82; N,
4.62. Found: C, 49.20; H, 5.15; N, 4.67.
Compound 9. Yield: 89 mg, 81%. Dec point 178 °C. 1H NMR
(400 MHz, CDCl3): δ ) 1.24 (s, 3 H, Me), 1.26 (s, 3 H, Me),
7.49-7.67 (m, 30 H, Ph), 8.99 (br, 1 H, NH). 13C{1H} NMR (100
MHz, CDCl3): δ ) 26.84 (s, Me), 28.88 (s, Me), 128.96 (vt, p-Ph,
N ) 10.2 Hz), 130.95 (vt, ipso-Ph, N ) 37.6 Hz), 131.03 (s, m-Ph),
134.17 (vt, o-Ph, N ) 13.3 Hz), 185.65 (s, CdN), 189.97 (dt, CO,
X-ray Structure Determinations. The structures of 5 and A
were solved (Table 1). Data were registered on a Bruker SMART
1000 CCD diffractometer at 133 K using Mo KR radiation (λ )
0.71073 Å) to a maximum 2θ of 60°. Absorption corrections were
applied using the program SADABS. Structures were solved by
the heavy-atom method and refined anisotropically on F2 (program
system SHELXL, G. M. Sheldrick, University of Go¨ttingen,
Germany). Hydrogen atoms were included as follows: NH and
coordinated olefin CH freely refined but with distance restraints,
rigid methyls, others riding.
2
1JC-Rh ) 65.63 Hz, JC-P ) 16.53 Hz). 31P{1H} (162 MHz,
1
CDCl3): δ ) 31.69 (d, PPh3, JP-Rh ) 129 Hz). IR (Nujol): ν )
3242 (m) (NH), 1994 (s) (CdO), 1662 (m) (CdN) cm-1. ΛM: 149
Ω-1 cm2 mol-1. Anal. Calcd for C40H37ClNO5P2Rh: C, 59.16; H,
4.59; N, 1.72. Found: C, 58.86; H, 4.85; N, 1.81.
1
Compound 10. Yield: 100 mg, 89%. Dec point 207 °C. H
NMR (200 MHz, CDCl3): δ ) 1.23 (s, 3 H, Me), 1.27 (s, 3 H,
Inorganic Chemistry, Vol. 42, No. 23, 2003 7647

Vicente et al.
Scheme 1
that could easily be separated upon filtration and precipitation
with Et2O to give 1 in 70% yield. The reaction times are
crucial because shorter periods of stirring in step 1 (5 or 20
min) lead to mixtures enriched in [Ag(NH3)2]ClO4 while
longer ones give diacetonamine complexes. On the other
hand, acetone solutions of AgClO4 with an excess of aqueous
NH3 resulted in mixtures containing 1 contaminated with
variable amounts of [Ag(NH3)2]ClO4, diacetonamine, and/
or triacetonamine and/or acetonine species (see Chart 1) and/
or other unidentified compounds, depending on the reaction
conditions. We were unable to separate these mixtures.
The gold complexes [Au(NHdCMe2)2]X (X ) ClO4,
CF3SO3), homologous to 1, were prepared in good yields
by stirring [Au(NH3)2]X in acetone for 5 days or by reacting
PPN[Au(acac)2] with NH4X in acetone, in a shorter time (3
h).16 However, we could not obtain pure 1 from [Ag(NH3)2]-
40
ClO4 and acetone, nor from NH4ClO4 and Ag2CO3 or
AgOAc. After 24 h of stirring, the reaction of [Ag(NH3)2]-
ClO4 and acetone produces a mixture of the starting silver
complex and a small amount of 1. When the stirring was
prolonged over 4 days, the mentioned mixture was contami-
nated with diacetonamine (B in Chart 1) or some “Ag-
(diacetonamine)” species (by 1H NMR). After many experi-
ments in which drying agents [anhydrous MgSO4 or CaCl2,
or Me2C(OMe)2] were added to the same reaction mixture,
with the intention of facilitating the condensation process,
we concluded that their use not only did not increase the
production of 1 but also, in some cases (CaCl2), produced
additionally triacetonamine (C in Chart 1) or some “Ag-
Compound 5. Crystal data: C29H34ClNO4PRh (629.90), mono-
clinic, P21/c, a ) 9.7384(8) Å, b ) 32.027(3) Å, c ) 17.5949(14)
Å, â ) 93.951(4)°, V ) 5474.6(8) Å3, Z ) 8, Fcalcd ) 1.528 Mg/
m3, µ ) 0.816 mm-1, F(000) ) 2592,; -13 e h e 13, -44 e k
e 45, -24 e l e 24; reflns collected, 96871; indep reflns, 16011
(Rint ) 0.0495), data/restraints/params 16011/29/711, GOF on F2
) 1.012, final R indices [I > 2σ(I)], R1 ) 0.0334, wR2 ) 0.0815,
R indices (all data) R1 ) 0.0557, wR2 ) 0.0902; largest diff peak
1
(triacetonamine)” complex (by H NMR). The reactions of
and hole 2.740 and -0.446 e Å-3
.
NH4ClO4 with Ag2CO3 or AgOAc also failed to give 1 since
a complex mixture, which we could not separate, was
obtained in the case of Ag2CO3, and no reaction was
observed with AgOAc. Experiments in refluxing acetone did
not give any better results.
[Ag{H2NC(Me)2CH2C(O)Me}(PTo3)]ClO4. Crystal data: C27H34-
AgClNO5P (626.84), triclinic, P1h, a ) 10.1821(8) Å, b )
12.2233(8) Å, c ) 12.4631(8) Å, R ) 100.159(4)°, â ) 108.292(4)°,
γ ) 96.667(4)°, V ) 1425.07(17) Å3, Z ) 2, Fcalcd ) 1.461 Mg/
m3, µ ) 0.893 mm-1, F(000) ) 644; -13 e h e 14, -17 e k e
17, -17 e l e 17; reflns collected, 29022; indep reflns, 8301 (Rint
) 0.0271), data/restraints/params 8301/1/339, GOF on F2 ) 0.982,
final R indices [I > 2σ(I)], R1 ) 0.0267, wR2 ) 0.0618, R indices
(all data) R1 ) 0.0368, wR2 ) 0.0649; largest diff peak and hole
In the mixture of products obtained after bubbling NH3(g)
through an acetone solution of AgClO4 (2 min), removing
the excess under vacuum, adding fresh acetone and anhy-
drous MgSO4, and stirring the suspension for 7 days, we
observed that a diacetonamine species was the major product,
contaminated with only small amounts of different impurities.
The compound precipitated as a very sticky oily product that,
even after many attempts, we could not convert into a solid.
By reacting it with PTo3 (To ) C6H4Me-4, in CH2Cl2,
AgClO4/PTo3 ) 1:1), a new mixture of products resulted,
from which, by the liquid diffusion method using CH2Cl2
and Et2O, single crystals grew of [Ag{H2NC(Me)2CH2C-
(O)Me}(PTo3)]ClO4 (A, Scheme 1), the crystal structure of
which was determined by X-ray diffraction methods. A
search of the Cambridge Crystallographic Data Center
(CCDC) reveals that this is the first crystal structure of a
diacetonamine complex of any metal.
0.635 and -0.299 e Å-3
.
Results and Discussion
Synthesis of [Ag(NHdCMe2)2]ClO4 (1) and [Ag{H2NC-
(Me)2CH2C(O)Me}(PTo3)]ClO4 (To ) C6H4Me-4) (A).
Complex 1 could be obtained by bubbling anhydrous NH3(g)
through an acetone solution of AgClO4 for 2 min (Scheme
1) and stirring the solution for 30 min (step 1). At this point,
the reaction was still not complete, since 1 was contaminated
with some [Ag(NH3)2]ClO440 (the IR spectrum shows a band
at 3364 cm-1 due to [Ag(NH3)2]ClO4). Although recrystal-
lization from CH2Cl2/Et2O removed most of the ammine
complex, treatment of the recrystallized product in CH2Cl2
with NaH (step 2) was necessary in order to obtain pure 1,
since only [Ag(NH3)2]ClO4 reacted to give metallic silver
along with some unidentified soluble decomposition products
Synthesis of Acetimine Complexes of Rhodium(I).
[Rh(diolefin)(NHdCMe2)2]ClO4 [diolefin ) 1,5-cycloocta-
diene ) cod (2), norbornadiene ) nbd (3)] and cis-[Rh(CO)2-
(NHdCMe2)2]ClO4 (4) were obtained in good yield (80-
87%) by reacting 1 in CH2Cl2 with the appropriate
[RhCl(diolefin)]2 or [RhCl(CO)2]2 complexes in 2:1 molar
(40) Miles, M. G.; Patterson, J. H.; Hobbs, C. W.; Hopper, M. J.; Overend,
J.; Tobias, R. S. Inorg. Chem. 1968, 7, 1721.
7648 Inorganic Chemistry, Vol. 42, No. 23, 2003

Synthesis of [Ag(NHdCMe2)2]ClO4
Scheme 2
Scheme 3
ratio (Scheme 2). The only byproduct, AgCl, was removed
by filtration.
Complexes 2 or 3 reacted in CH2Cl2 with the equimolar
amount of PPh3, to give the cationic complex [Rh(diolefin)-
(NHdCMe2)(PPh3)]ClO4 [diolefin ) cod (5), nbd (6)]
(Scheme 2). Whereas complex 5 was obtained pure, complex
6 was contaminated with Ph3PO [31P{1H} NMR]. The
isolation of pure 6 required working in a dry nitrogen
atmosphere and using acetone as solvent. Similarly, the
neutral complexes [RhCl(diolefin)(NHdCMe2)] [diolefin )
cod (7), nbd (8)] were obtained by reacting 2 or 3,
respectively, with Me4NCl (1:1.1, in acetone, under nitrogen).
The byproduct Me4NClO4, and the excess of Me4NCl, were
separated by extracting the complex with Et2O (7) or CH2Cl2
(8). When other ammonium salts (PPNCl, Bu4NCl) were
used instead of Me4NCl, the resulting perchlorate salt could
not be separated from the corresponding complex even after
repeated recrystallizations.
High yields of pure trans-[Rh(CO)(NHdCMe2)(PR3)2]-
ClO4 [R ) Ph (9), C6H4Me-4 (To) (10)] were obtained by
reacting 4 with 2 equiv of the appropriate phosphine (Scheme
3). Complex 9 was also obtained, though in lower yield
(52%), by reacting 1 with [RhCl(CO)(PPh3)2] (1:1, 45 min,
in acetone). However, the dropwise addition of 1 equiv of
PPh3 to 4 in CH2Cl2, intended to produce a monosubstituted
product ([Rh(CO)(NHdCMe2)2(PPh3)]ClO4 or [Rh(CO)2-
(NHdCMe2)(PPh3)]ClO4), gave instead a mixture of com-
pounds that we could not separate. Its 1H and 31P{1H} NMR
spectra showed the presence of a small amount of complex
9, while the remaining H and 31P{1H} NMR resonances
suggest the main component of the mixture to be one of the
expected complexes cis-[Rh(CO)(NHdCMe2)2(PPh3)]ClO4
(11) (Scheme 3). A 10:1 (11:9) molar ratio was deduced from
the 31P{1H} NMR spectrum of the mixture. Following the
reaction course by 1H and 31P{1H} NMR, both in the air or
in CO atmosphere, showed the disubstitution product 9 to
be present in the first measured spectra. The solid IR
spectrum of the mixture reveals the presence of a small
amount of 4, the 1H NMR resonances of which were
obscured by those of the other complexes. Pure 11 could be
obtained in very good yield by reacting 1 with [RhCl(CO)-
(PPh3)]2 (1:2) in CH2Cl2 (Scheme 3)
1
Although the exclusive formation of 11 would suggest a
greater trans effect of acetimine with respect to CO, its
formation can be better understood in terms of the destabiliz-
ing effect of two mutually trans π-acidic ligands on RhI
complexes.41 In fact, a search of the CCDC for mononuclear
square planar RhI complexes reveals the great tendency of
CO to avoid CO or PPh3 ligands in trans position since, apart
from [Rh(CO)4]+ 42 and two [Rh(CO)2(PR3)2]+ complexes
with very bulky phosphine ligands,43,44 trans-[Rh(CO)2Cl2]- 45
(41) Cavallo, L.; Sola`, M. J. Am. Chem. Soc. 2001, 123, 12294.
(42) Lupinetti, A. J.; Havighurst, M. D.; Miller, S. M.; Anderson, O. P.;
Strauss, S. H. J. Am. Chem. Soc. 1999, 121, 11920.
(43) Dunbar, K. R.; Haefner, S. C. J. Am. Chem. Soc. 1991, 113, 9540.
Inorganic Chemistry, Vol. 42, No. 23, 2003 7649

Vicente et al.
Table 2. Hydrogen Bonds [Å and deg] for 5a
D-H‚‚‚A
d(D-H) d(H‚‚‚A) d(D‚‚‚A)
(DHA)
3.110(3) 172(3)
3.092(3) 169(3)
N(1)-H(01)‚‚‚O(3)
0.79(2)
0.80(2)
0.95
0.95
0.99
2.32(2)
2.31(2)
2.40
2.47
2.52
2.54
2.54
2.55
N(1′)-H(01′)‚‚‚O(8)
C(25)-H(25)‚‚‚O(1)#1
C(22)-H(22)‚‚‚O(7)#2
C(8)-H(8A)‚‚‚O(5)#2
C(35)-H(35)‚‚‚O(4)
3.261(3)
3.421(3)
3.503(3)
3.309(4)
3.482(4)
3.182(4)
150.9
175.3
170.8
137.8
161.1
124.3
0.95
C(10)-H(10B)‚‚‚O(8)#3 0.98
C(44)-H(44)‚‚‚O(8)#4
C(1′)-H(1′)‚‚‚O(6)
0.95
0.962(16)
C(33′)-H(33′)‚‚‚O(6)#5 0.95
2.54(2)
2.56
3.348(4) 141(2)
3.510(3) 177.4
a Symmetry transformations used to generate equivalent atoms: #1, x
1
1
- 1, -y + /2, z - /2; #2, -x + 1, -y, -z + 1; #3, x + 1, y, z + 1; #4,
x, y, z + 1; #5, x + 1, y, z.
Figure 1. Crystal structure of complex 5 showing the atom numbering.
Ellipsoids correspond to 30% probability levels. Selected bond lengths [Å]
and angles [deg]: Rh(1)-N(1) 2.070(2), Rh(1′)-N(1′) 2.093(2), Rh(1)-
C(5) 2.153(2), Rh(1′)-C(5′) 2.124(3), Rh(1)-C(6) 2.168(2), Rh(1′)-C(6′)
2.155(3), Rh(1)-C(1) 2.210(2), Rh(1′)-C(1′) 2.215(3), Rh(1)-C(2) 2.215(2),
Rh(1′)-C(2′) 2.245(2), Rh(1)-P(1) 2.3371(6), Rh(1′)-P(1′) 2.3003(6),
N(1)-C(9) 1.279(3), N(1′)-C(9′) 1.276(3), C(1)-C(2) 1.375(3), C(1′)-
C(2′) 1.369(4), C(5)-C(6) 1.396(3), C(5′)-C(6′) 1.387(4); N(1)-Rh(1)-
C(1) 88.85(9), N(1′)-Rh(1′)-C(1′) 90.33(9), N(1)-Rh(1)-C(2) 89.16(9),
N(1′)-Rh(1′)-C(2′) 89.26(9), N(1)-Rh(1)-P(1) 90.01(6), N(1′)-Rh(1′)-
P(1′) 89.42(6), C(5)-Rh(1)-P(1) 89.45(7), C(5′)-Rh(1′)-P(1′) 92.76(8),
C(6)-Rh(1)-P(1) 98.32(7), C(6′)-Rh(1′)-P(1′) 95.57(7).
is the only example of a trans-(CO)2RhI complex, while
[Rh(CO)(PPh3)3]+ 46 is the only complex with CO trans to
PPh3. Accordingly, complexes 9-11 would be the thermo-
dynamic results of the corresponding reactions.
Figure 2. Crystal structure of complex A showing the atom numbering.
Ellipsoids correspond to 50% probability levels. Selected bond lengths [Å]
and angles [deg]: Ag-N 2.1677(14), Ag-P 2.3385(4), Ag-O(1) 2.6568(11),
N-Ag-P 167.08(4), N-Ag-O(1) 81.16(5), P-Ag-O(1) 111.62(3).
Crystal Structure of [Rh(cod)(NHdCMe2)(PPh3)]ClO4
(5). The crystal structure of 5 (Figure 1) involves two
independent formula units; the [Rh(cod)(NHdCMe2)(PPh3)]+
cations display only small differences in bond distances and
angles. The cations show the rhodium atoms in slightly
distorted square-planar environments, the coordinating double
bonds being defined in terms of their midpoints. The Rh-
C(5), Rh-C(5′) and Rh-C(6), Rh-C(6′) distances are longer
than Rh-C(1), Rh-C(1′) and Rh-C(2), Rh-C(2′), in
agreement with the greater trans influence of PPh3 with
respect to the imine. The CdN bond distances [1.279(3),
1.276(3) Å] are in the range found for the few other acetimine
complexes structurally characterized [1.259(4)-1.290(10)
Å].16,21,22,24-26 The acetimine ligand is almost coplanar with
the trans olefinic group from cod (interplanar angles 13.6°
and 7.8°). Classical hydrogen bonds N-H‚‚‚O are formed
between the perchlorate anions and the NH groups of the
acetimine ligands (Table 2). A further eight interactions
C-H‚‚‚O, with H‚‚‚O < 2.6 Å and angles > 120°, may be
regarded as weak hydrogen bonds. Most of them are involved
in forming broad layers of cations and anions parallel to the
xz plane.
Figure 3. Packing diagram of A viewed parallel to the y axis. Secondary
contacts (see text) are drawn as dashed bonds.
(Figures 2 and 3) consists of perchlorate anions and [Ag{H2-
NC(Me)2CH2C(O)Me}(PTo3)]+ cations in which the silver
atom is surrounded by the atoms P, N, and (at the greater
distance of 2.6568(11) Å) O(2) to give an essentially planar
but distorted T-shaped environment [P-Ag-N 167.08(4)°,
N-Ag-O(1) 81.16(5)°, P-Ag-O(1) 111.62(3)°]. There is
only one reported crystal structure of a silver complex
Crystal Structure of [Ag{H2NC(Me)2CH2C(O)Me}-
(PTo3)]ClO4. The crystal structure of the title compound
(44) Numberg, O.; Werner, H. J. Organomet. Chem. 1993, 460, 163.
(45) Matsubayashi, G.; Yokoyama, K.; Tanaka, T. J. Chem. Soc., Dalton
Trans. 1988, 253.
(46) Clark, H. C. S.; Coleman, K. S.; Fawcett, J.; Holloway, J. H.; Hope,
E. G.; Langer, J.; Smith, I. M. J. Fluorine Chem. 1998, 91, 207.
7650 Inorganic Chemistry, Vol. 42, No. 23, 2003

Synthesis of [Ag(NHdCMe2)2]ClO4
Table 3. Hydrogen Bonds [Å and deg] for Aa
assigned by comparison with those of the free ligand and
the bis(imine) complexes 2 and 3. In all cases, the resonances
from the CHdCH moieties are high field shifted with respect
to those in the free ligands.
The 31P{1H} NMR spectra of the phosphino complexes
5, 6, 9, and 10 show, in all cases, one doublet arising from
coupling with 103Rh, thus requiring the bis(phosphino)
complexes 9 and 10 to be of trans geometry and the reactions
leading to them to be stereoselective. Comparison of the
1JP-Rh coupling constants in 5 and 6 (around 160 Hz), with
those in 9 and 10, (around 128 Hz) suggests the trans
influence of triarylphosphines to be greater than that of
olefins.
D-H‚‚‚A
d(D-H) d(H‚‚‚A) d(D‚‚‚A)
(DHA)
N-H(01)‚‚‚O(2)
0.833(15) 2.339(16) 3.1327(19) 159.4(18)
0.818(15) 2.280(15) 3.089(2)
N-H(02)‚‚‚O(4)#1
170.3(18)
169.7
169.5
172.4
172.9
C(27)-H(27B)‚‚‚O(2)#2 0.98
2.61
2.58
2.60
2.46
3.580(2)
3.520(2)
3.545(2)
3.449(2)
C(12)-H(12)‚‚‚O(3)#1
C(26)-H(26)‚‚‚O(4)
C(3)-H(3B)‚‚‚O(5)#3
0.95
0.95
0.99
a Symmetry transformations used to generate equivalent atoms: #1, -x
+ 1, -y + 1, -z; #2, -x + 2, -y + 1, -z + 1; #3, x - 1, y, z.
containing a primary amine and a phosphine (PMe3).47 Its
Ag-P (2.373 Å) and Ag-N (2.367 Å) distances are greater
than those in our complex [2.3385(4) and 2.1677(14) Å,
respectively]. There is also only one reported crystal structure
of a silver complex containing an intramolecular Ag‚‚‚Od
CR2 contact through five bonds,48 with a Ag‚‚‚O distance
(2.601 Å) slightly shorter than in our complex [2.6568(11)
Å]. The perchlorate oxygens act as acceptors for a variety
of secondary interactions; classical hydrogen bonds
N-H‚‚‚O, weak hydrogen bonds C-H‚‚‚O (Table 3), and
contacts Ag‚‚‚O [Ag‚‚‚O(4) 3.17 Å, Ag‚‚‚O(3) (1 - x, 1 -
y, -z) 3.15 Å]. The classical hydrogen bonds, Ag‚‚‚O
contacts, and the shortest C-H‚‚‚O combine to link the
residues into chains parallel to the x axis (Figure 3).
IR Spectra. The vibrational spectra of NHdCMe2 show
two weak ν(NH) bands (Raman, 3326 and 3260 cm-1) and
two ν(CdN) bands (IR, 1658, 1670 sh cm-1).3 In the IR
spectra of complexes 1-10, a medium to strong broad ν(NH)
band is observed in the 3186-3294 cm-1 region. Only one
absorption is observed in the 1652-1666 cm-1 range from
the ν(CdN) stretching mode, both for the mono- and bis-
(imine) derivatives although the related complex [Au(NHd
CMe2)2]ClO4 shows two bands in the same region (1660,
1643 cm-1). The IR spectrum of 4 shows two ν(CO) bands
(2092, 2026 cm-1) supporting its cis (C2V) geometry. In the
spectra of 9 and 10, the only ν(CO) band is observed at 1994
cm-1. The lower energy of the band in the bis(phosphine)
complexes 9 and 10 can be accounted for in terms of the
better σ-donor and poorer π-acceptor ability of two phos-
phine ligands with respect to the substituted CO and imine
ligands in 4.
NMR Spectra. The CD3CN 1H NMR spectrum of NHd
3
CMe2 shows one singlet (δ ) 1.93 ppm) for both Me groups
1
while the NH resonance is not observed. The H NMR
spectra of complexes 1-10 show the NH resonance as a
broad signal in the 8.27-9.30 ppm range.
1
At room temperature, the H NMR spectrum of complex
4
2 shows two resonances [δ 2.14 (d, JH-H ) 0.8 Hz), 2.52
(s)] indicating the restricted rotation around the CdN bond
at room temperature whereas in complexes 3-5 and 7-10
two singlets are observed. In those reported complexes giving
Conclusions
Although acetimine is unstable, it can be stabilized by
coordination to silver(I). [Ag(NHdCMe2)2]ClO4 (1) was
prepared by reacting AgClO4 and NH3 in acetone. The use
of 1 as a transmetallating agent toward various chloro
complexes of Rh(I) opens a new route for the synthesis of
acetimino derivatives. The first Rh(I) complexes containing
acetimine were prepared and characterized.
1
only one doublet in their H NMR spectra,14,16-18,20,24,25,27
therefore corresponding to the Me trans to the NH proton,
this resonance is at lower frequency than the other one
appearing as a singlet. This allows the same assignment for
the doublet at 2.14 ppm in 2 and for the singlet at lower
frequency in all the other complexes. In the room-temperature
spectra of complexes 1 and 6, only one singlet resonance is
observed for both Me groups, suggesting the free rotation
of the CdN bond, as previously observed in the spectrum
of [Au(NHdCMe2)(PPh3)]ClO4 at 60 °C.16 However, the
acetone-d6 spectrum of 1 between -60 and -90 °C shows
two singlets (2.25, 2.28 ppm). In the cod and nbd complexes
5-8, the signals corresponding to the olefinic protons were
Acknowledgment. We thank Ministerio de Ciencia y
Tecnolog´ıa, FEDER (BQU2001-0133), and the Fonds der
Chemischen Industrie for financial support. R.G. thanks
Cajamurcia (Spain), and I.V.-H. thanks Fundacio´n Se´neca
for grants.
Supporting Information Available: Tables of X-ray data for
the complexes in CIF format. This material is available free of
charge via the Internet at http://pubs.acs.org.
(47) Plappert, E. C.; Mingos, D. M. P.; Lawrence, S. E.; Williams, D. J. J.
Chem. Soc., Dalton Trans. 1997, 2119.
(48) Blake, A. J.; Champness, N. R.; Howdle, S. M.; Morley, K. S.; Webb,
P. B.; Wilson, C. CrystEngComm 2002, 4, 88.
IC035002+
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