Cationic rhodium(I) complexes formed in the reactions of HRh(CO)L 3 (L=PPh3, P(OPh)3) complexes with silver(I) salts

Article abstract of DOI:10.1016/S0020-1693(02)01551-7

The reactions of HRh(CO)L₃ (L=PPh₃, P(OPh) ₃) complexes with AgY (Y=BF₄^-, CF ₃SO₃^-, PF₆^-) lead to [Rh(CO)(PPh₃)₂(H₂O)]Y and [Rh(CO)(P(OPh) ₃)₃]Y compounds. The solvolysis of [Rh(CO)(PPh ₃)₂(H₂O)]PF₆ in ethanol produced a crystalline trans-[Rh(CO)(PPh₃)₂(OPOF₂)] complex containing distorted square-planar rhodium center. The different arrangement of OPOF₂^- ligands found in two crystallographically independent molecules is connected with the presence of intra- and intermolecular C-H...O hydrogen bonds involving both oxygen atoms of each OPOF₂^- anion. The reaction of [Rh(CO)(P(OPh) ₃)₃]Y (Y=BF₄^-, PF₆ ^-) in solution with CO leads to [Rh(CO)₂(P(OPh) ₃)₃]Y and with P(OPh)₃ to [Rh(P(OPh) ₃)₄]Y complexes. The [Rh(P(OPh)₃) ₄]PF₆ complex was also obtained as a final reaction product of HRh(P(OPh)₃)₄ with AgPF₆.

Full text of DOI:10.1016/S0020-1693(02)01551-7

Inorganica Chimica Acta 350 (2003) 339Á346
/
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Cationic rhodium(I) complexes formed in the reactions of
HRh(CO)L3 (LꢀPPh3, P(OPh)3) complexes with silver(I) salts
/
Anna M. Trzeciak, Zofia Olejnik, Jo´zef J. Zio´ lkowski *, Tadeusz Lis
Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie St., Wroclaw 50-383, Poland
Received 1 July 2002; accepted 25 September 2002
In honor of Professor Pierre Braunstein
Abstract
The reactions of HRh(CO)L3 (Lꢀ
/
PPh3, P(OPh)3) complexes with AgY (Yꢀ , , ) lead to
BF4ꢁ CF3SO3ꢁ PF6ꢁ
/
[Rh(CO)(PPh3)2(H2O)]Y and [Rh(CO)(P(OPh)3)3]Y compounds. The solvolysis of [Rh(CO)(PPh3)2(H2O)]PF6 in ethanol produced
a crystalline trans-[Rh(CO)(PPh3)2(OPOF2)] complex containing distorted square-planar rhodium center. The different arrange-
ment of OPOF2ꢁ ligands found in two crystallographically independent molecules is connected with the presence of intra- and
intermolecular Cꢀ
/
H. . .O hydrogen bonds involving both oxygen atoms of each OPOF2ꢁ anion. The reaction of [Rh(CO)(P(O-
Ph)3)3]Y (Yꢀ
/
BF4ꢁ, PF6ꢁ) in solution with CO leads to [Rh(CO)2(P(OPh)3)3]Y and with P(OPh)3 to [Rh(P(OPh)3)4]Y complexes.
The [Rh(P(OPh)3)4]PF6 complex was also obtained as a final reaction product of HRh(P(OPh)3)4 with AgPF6.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Hydridorhodium(I) complexes; Rhodium(II) complexes; Cationic Rh(I) complexes
samples obtained by another route [7,8]. The products
1. Introduction
of electrochemical oxidation of HRh(CO)(PPh3)3 have
never been isolated in solid.
In this paper, we present the studies of the reactions of
Hydridocarbonyl
rhodium(I)
complexes
of
HRh(CO)L3 formula (Lꢀ
known as catalyst precursors or intermediates in hydro-
formylation, isomerization, and hydrogenation reac-
/PPh3, P(OPh)3) are well
HRh(CO)L3 (LꢀPPh3, P(OPh)3) complexes with che-
/
mical oxidants, Ag(I) salts, performed with the aim to
isolate the final reaction products. On the basis of
literature data cited above, it was expected that in both
reactions, of phosphino and phosphito hydridocarbo-
nyls, cationic complexes of [Rh(CO)L3]ꢂ-type would be
obtained and isolated. As far as we know, the prepara-
tion of [Rh(CO)(P(OPh)3LI)3]ꢂ complexes was not
reported until now.
tions of unsaturated substrates [1Á3].
The electrochemical oxidation of HRh(CO)(PPh3)3
has been studied very carefully by different research
/
groups [4Á6]. It was found that one-electron oxidation
/
leads to 17-electron monomeric cationic species
[HRh(CO)(PPh3)3]ꢂ of square-pyramidal structure
with a phosphorus atom in apical position [4]. The
electron spin resonance (ESR) as well as UVÁVis
/
spectra of [HRh(CO)(PPh3)3]ꢂ have been reported [4].
Further oxidation led to [HRh(CO)(PPh3)3]2ꢂ, which
2. Results and discussion
undergoes
deprotonation
forming
finally
2.1. Reaction of HRh(CO)(PPh3)3 complex with AgY
(Yꢀ
PF6ꢁ, CF3SO3ꢁ, BF4ꢁ)
[Rh(CO)(PPh3)3]ꢂ-type complexes [4,5], which have
been identified only in solution by comparison with
/
Reactions of HRh(CO)(PPh3)3 complex with AgY
salts (Yꢀ
PF6ꢁ, BF4ꢁ, CF3SO3ꢁ) in CH2Cl2 solution
were studied at room temperature at different [Ag]:[Rh]
/
* Corresponding author. Tel.: ꢂ
7356.
E-mail address: jjz@wchuwr.chem.uni.wroc.pl (J.J. Zio´ lkowski).
/
48-71-375 7356; fax: ꢂ48-91-375
/
ratios (ranging from 0.5 to 2.5). In all experiments, the
0020-1693/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0020-1693(02)01551-7

340
A.M. Trzeciak et al. / Inorganica Chimica Acta 350 (2003) 339Á346
/
formation of silver metal precipitate confirmed the
occurrence of a redox process. The final products of
the reactions of HRh(CO)(PPh3)3 with Ag(I) salts were
complexes [Rh(CO)(PPh3)2(H2O)]Y formula (Yꢀ
PF6ꢁ,
/
BF4ꢁ, CF3SO3ꢁ) characterized by 31P NMR and IR
spectra (reaction (1)). The spectroscopic data were
compared with those of [Rh(CO)(PPh3)2(H2O)]Y (Yꢀ
/
CF3SO3ꢁ, BF4ꢁ) complexes obtained earlier by another
route, in reactions of RhCl(CO)(PPh3)2 with respective
AgY salts [9]. According to literature data [9], complexes
with Yꢀ
CF3SO3ꢁ and BF4ꢁ ligands exist as aqua
/
complexes of the [Rh(CO)(PPh3)2(H2O)]Y-type; how-
ever, the existence of [Rh(CO)(PPh3)2(SO3CF3)] has also
been reported [10].
Fig. 1. The packing fragment showing two independent molecules of
trans-Rh(CO)(PPh3)2(OPOF2) with 50% ellipsoids. The intramolecu-
lar CꢀH. . .O hydrogen bonds are marked by dashed lines. The dotted
/
circles represent the minor component of the disordered OPOF2ꢁ
group.
ð1Þ
[Rh(CO)(PPh3)3](CF3SO3) complex. The isolated rho-
dium
[Rh(CO)(PPh3)2(H2O)](CF3SO3) by the characteristic
complex
was,
however,
identified
as
doublet in 31P NMR (dꢀ
Hz) (reaction (2)):
/
29.8 ppm, J(Rhꢀ
/
P)ꢀ
/
124
ð2Þ
The same product was also obtained in the reaction of
HRh(CO)(PPh3)3 with triflic acid (reaction (3)):
HRh(CO)(PPh3)3
Scheme 1.
ꢂCF3SO3H 0[Rh(CO)(PPh3)2(H2O)](CF3SO3)
ꢂH2
(3)
The water molecule in coordination sphere of rhodium
origins from hygroscopic silver (I) salts used as oxidants.
By recrystallization of the crude product of the
reaction of HRh(CO)(PPh3)3 with AgPF6 from not
carefully dried ethanol, Rh(CO)(PPh3)2(OPOF2) com-
plex was obtained and its structure was determined by
X-ray structural analysis (Fig. 1). This complex was
obtained and characterized earlier; however, X-ray data
were not published [9]. The solvolysis of the PF6ꢁ ligand
and OPOF2ꢁ anion formation were already reported for
Reaction (1) of HRh(CO)(PPh3)3 with AgY salt was
monitored using the IR spectra measurements and the
representative results obtained at the concentration ratio
[Ag]:[Rh]ꢀ0.7 are shown in Fig. 2. Immediately (ca. 2
/
min) after the addition of solid HRh(CO)(PPh3)3 to the
solution of silver salt in CH2Cl2, the n(CO) band at 1920
cmꢁ1 and the n(Rhꢀ
/
H) band at 2006 cmꢁ1, originating
from the starting complex, disappeared and a new
n(CO) band at 2000 cmꢁ1 was observed. When instead
of HRh(CO)(PPh3)3, its deuterated analogue,
DRh(CO)(PPh3)3 (n(CO) 1960 cmꢁ1), was used, the
band at 2000 cmꢁ1 was also observed at the beginning
of the reaction. This new n(CO) frequency, which
intensity decreased in time, was assigned to the unstable
Rh(II) cationic complex, [HRh(CO)(PPh3)3]ꢂ (reaction
(1)). Decomposition of [HRh(CO)(PPh3)3]ꢂ led to
[Rh(CO)(PPh3)3]ꢂ complex, evidenced by the appear-
ance of a new n(CO) band at 1970 cmꢁ1 (Fig. 2). The
other systems [9,11Á13].
/
It was surprising that in the reaction of
HRh(CO)(PPh3)3 with AgY salts, we obtained
[Rh(CO)(PPh3)2(H2O)]ꢂ cationic species as final pro-
ducts instead of expected [Rh(CO)(PPh3)3]ꢂ. Therefore,
for comparison, the reaction of RhCl(PPh3)3 with
Ag(CF3SO3) was studied (see Scheme 1).
It was expected that this reaction performed in the
atm)
presence
of
CO
(1
would
produce

A.M. Trzeciak et al. / Inorganica Chimica Acta 350 (2003) 339Á
/346
341
Table 1
˚
Selected geometric parameters (A, 8) for trans-Rh(CO)(PPh3)2
(OPOF2)
Molecule I
Molecule II
Rh(1)ꢀ
Rh(1)ꢀ
Rh(1)ꢀ
Rh(1)ꢀ
C(1)ꢀ
P(1)ꢀ
P(1)ꢀ
P(1)ꢀ
P(2)ꢀ
P(2)ꢀ
P(2)ꢀ
P(3)ꢀ
P(3)ꢀ
P(3)ꢀ
P(3)ꢀ
C(1)ꢀ
C(1)ꢀ
O(11)ꢀ
C(1)ꢀRh(1)ꢀ
O(11)ꢀRh(1)ꢀ
P(2)ꢀRh(1)ꢀP(1)
O(1)ꢀC(1)ꢀRh(1)
C(13)ꢀP(1)ꢀ
C(13)ꢀP(1)ꢀ
C(12)ꢀP(1)ꢀ
C(13)ꢀP(1)ꢀ
C(12)ꢀP(1)ꢀ
C(11)ꢀP(1)ꢀ
C(16)ꢀP(2)ꢀ
/
C(1)
O(11)
P(2)
1.794(2) Rh(2)ꢀ
2.089(2) Rh(2)ꢀ
2.3346(9) Rh(2)ꢀ
2.3359(8) Rh(2)ꢀ
1.152(3) C(2)ꢀ
1.819(2) P(4)ꢀ
1.824(2) P(4)ꢀ
1.829(2) P(4)ꢀ
1.824(2) P(5)ꢀ
1.825(2) P(5)ꢀ
1.836(3) P(5)ꢀ
1.473(2) P(6)ꢀ
1.481(3) P(6)ꢀ
1.558(2) P(6)ꢀ
1.531(2) P(6)ꢀ
/
C(2)
O(12)
P(5)
1.793(2)
2.091(2)
2.3269(9)
2.3430(8)
1.155(3)
1.825(2)
1.829(2)
1.835(2)
1.820(2)
1.823(2)
1.827(2)
1.456(2)
1.469(2)
1.546(2)
1.553(2)
/
/
/
/
/P(1)
/P(4)
/
O(1)
/
O(2)
/
C(13)
C(12)
C(11)
C(16)
C(14)
C(15)
O(11)
O(21) a
F(31) a
F(41)
/
C(17)
C(18)
C(19)
C(110)
C(111)
C(112)
O(22)
O(12)
F(32)
F(42)
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
Rh(1)ꢀ
Rh(1)ꢀ
/
O(11)
173.33(9)
89.51(8)
92.40(5)
90.90(8)
87.92(5)
173.60(2)
177.3(2)
C(2)ꢀ
C(2)ꢀ
O(12)ꢀ
C(2)ꢀRh(2)ꢀ
O(12)ꢀ
P(5)ꢀRh(2)ꢀ
O(2)ꢀC(2)ꢀRh(2)
P(4)ꢀ
P(4)ꢀ
P(4)ꢀ
P(4)ꢀ
P(4)ꢀ
P(4)ꢀ
P(5)ꢀ
/
Rh(2)ꢀ
/
O(12) 174.01(9)
/
/
P(2)
/
Rh(2)ꢀ
/
P(5)
92.20(8)
89.07(5)
/
Rh(1)ꢀ
P(1)
P(1)
/P(2)
/
Rh(2)ꢀ
/P(5)
/
/
/
/
P(4)
90.08(7)
/
/
/
Rh(2)ꢀ
/P(4)
90.47(5)
162.47(2)
176.6(2)
Fig. 2. IR spectra in CH2Cl2 measured during the reaction of
HRh(CO)(PPh3)3 with Ag(CF3SO3) ([Rh]:[Ag]ꢀ1:0.7). The arrows
show decrease of the band intensity.
or increase (¡
[HRh(CO)(PPh3)3]ꢂ: n(CO) 2000 cmꢁ1; [Rh(CO)(PPh3)3]ꢂ: n(CO)
1970 cmꢁ1; and unidentified product: n(CO) 2028 cmꢁ1
/
/
/
/
P(4)
/
/
/
/
/
(
/)
/)
/
/
C(12)
C(11)
C(11)
Rh(1)
Rh(1)
Rh(1)
C(14)
104.15(10) C(17)ꢀ
103.44(10) C(17)ꢀ
106.88(10) C(18)ꢀ
118.29(7)
114.15(7)
108.90(7)
/
/
C(18)
C(19)
C(19)
Rh(2)
Rh(2)
Rh(2)
104.07(10)
106.60(11)
105.08(10)
116.76(8)
115.51(7)
107.91(8)
103.52(10)
/
/
/
/
.
/
/
/
/
/
/
C(17)ꢀ
C(18)ꢀ
C(19)ꢀ
/
/
/
/
/
/
/
/
/
/
small amount of the second unidentified product with
n(CO) 2028 cmꢁ1 was also observed. The formation of
Rh(I) cationic complex from [HRh(CO)(PPh3)3]ꢂ inter-
mediate was accompanied with H2 evolution. In the test
reaction, the gas evolved was introduced to a solution of
[Rh(P(OPh)3)4]ClO4 in CDCl3, which was next analyzed
/
/
106.82(10) C(110)ꢀ
/
/
C(111)
C(16)ꢀ
/
P(2)ꢀ/C(15)
101.49(11) C(110)ꢀ
/
P(5)ꢀ
/
105.14(10)
105.76(11)
C(112)
C(14)ꢀ
/
P(2)ꢀ/C(15)
105.87(11) C(111)ꢀ
/
P(5)ꢀ
/
C(112)
1
C(16)ꢀ
C(14)ꢀ
C(15)ꢀ
P(3)ꢀO(11)ꢀ
O(11)ꢀP(3)ꢀ
O(11)ꢀP(3)ꢀ
P(3)ꢀ
/
P(2)ꢀ
P(2)ꢀ
P(2)ꢀ
/
Rh(1)
Rh(1)
Rh(1)
114.51(8)
110.82(7)
116.39(8)
C(110)ꢀ
C(111)ꢀ
C(112)ꢀ
O(12)ꢀ
O(21) a 120.97(14) O(12)ꢀ
P(6)ꢀ
F(41) P(6)ꢀ
107.54(11) O(12)ꢀ
F(31) a 106.24(11) O(12)ꢀ
P(6)ꢀ
F(41) 116.7(2)
P(6)ꢀ
105.69(15) O(22)ꢀP(6)ꢀ
/
P(5)ꢀ
P(5)ꢀ
P(5)ꢀ
/
Rh(2) 119.16(8)
Rh(2) 120.30(8)
Rh(2) 101.26(7)
by H NMR. The presence of a hydrido resonance at
/
/
/
/
dꢀ
/
ꢁ
/
9.55 ppm split into two characteristic multiplets
/
/
/
/
because of a Pꢀ
/
H coupling (J(PꢀHtrans)ꢀ222 Hz)
/
/
/
/
Rh(1)
154.08(12) P(6)ꢀ
/
/
Rh(2)
162.10(11)
122.70(10)
106.08(9)
106.61(9)
110.23(10)
110.54(10)
/
/
/
/
O(22)
F(32)
F(42)
F(42)
F(32)
confirmed the presence of [RhH2(P(OPh)3)4]ClO4 (reac-
tion (4)):
/
/
/
/
O(11)ꢀ
/
/
/
/
O(21) a
O(21) a
F(31) a
ꢀ
ꢀ
/
P(3)ꢀ
P(3)ꢀ
/
O(22)ꢀ
/
/
/
/
/
/
ð4Þ
F(41)ꢀ
/
P(3)ꢀ
/
F(31) a
96.21(12) F(32)ꢀ
/
P(6)ꢀ
/F(42)
97.74(10)
It can be concluded that the IR spectra confirmed the
formation of [Rh(CO)(PPh3)3]ꢂ complexes during the
reaction of HRh(CO)(PPh3)3 with AgY salts, similarly
as it was reported for electrochemical oxidation reaction
a
Occupancy: 0.77.
plex. The views of these molecules are depicted in Fig. 1
and selected bond lengths and angles are collected in
Table 1. Each molecule consists of a distorted square-
planar rhodium center with the PPh3 groups in trans
positions and the remaining trans positions occupied by
carbonyl and the O-bonded difluorophosphate anion.
Both molecules display the same eclipsed arrangement
of the two phosphine ligands with the carbonyl ligand
sandwiched between two phenyl rings. There are marked
distortions of the Rh coordination geometry toward
[4Á6]. However, we were not able to isolate these species
/
and in all experiments [Rh(CO)(PPh3)2(H2O)]ꢂ cationic
complexes were obtained instead.
2.2. Crystal structure of trans-
Rh(CO)(PPh3)2(OPOF2)
The unit cell contains two crystallographically inde-
pendent molecules of the Rh(CO)(PPh3)2(OPOF2) com-

342
A.M. Trzeciak et al. / Inorganica Chimica Acta 350 (2003) 339Á346
/
tetrahedral in the two independent molecules, evident
both from the PꢀRhꢀP and CꢀRhꢀO angles of
173.60(2)8 and 173.33(9)8 for Rh(1), and of 162.47(2)8
and 174.01(9)8 for Rh(2) as well as from the displace-
ment of the donor atoms from their mean plane by up to
˚
approximately 0.12 A for atoms bonded to Rh(1) and
˚
up to approximately 0.24 A for atoms bonded to Rh(2).
Additionally, the Rh(2) atom is displaced by approxi-
Table 2
˚
Hydrogen bond like close contacts (A, 8) for trans-Rh(CO)(PPh3)2
(OPOF2)
/
/
/
/
Dꢀ/H. . .A
d(H. . .A)
d(D. . .A)
B(DHA)
/
C(23)ꢀ
C(66)ꢀ
C(212)ꢀ
C(67)ꢀ
C(69)ꢀ
C(35)ꢀ
C(511)ꢀ
/H(23). . .O(11)
2.50
2.63
2.65
2.56
2.72
3.03
3.17
2.52
2.58
2.58
2.65
2.50
2.42
2.56
2.65
3.286(3)
3.357(3)
3.427(3)
3.277(3)
3.360(3)
3.923(3)
3.973(3)
3.138(3)
3.169(3)
3.176(3)
3.211(3)
3.317(4)
3.318(3)
3.281(8)
3.305(8)
141
133
139
133
126
157
144
123
121
121
118
144
158
133
127
/H(66). . .O(11)
/
H(212). . .O(22)
/
H(67). . .O(12)
H(69). . .Rh(2)
H(35). . .Rh(2)
˚
mately 0.12 A out of the mean plane of its donor atoms.
All RhꢀP, RhꢀC, and CꢀO bond distances are within
the ranges found for other complexes of the trans-
Rh(PPh3)2(CO)L-type [14Á19], where L is a neutral
molecule (H2O, CH3CN) or anion (Clꢁ, ClO3ꢁ, HCO2ꢁ,
CF3CO2ꢁ, PhOꢁ). The mean Rhꢀ
O distance of 2.090(2)
A, found in the present structure, lies between 2.130Á
/
/
/
/
/
/
H(511). . .Rh(1)
a
C(33)ꢀ
C(43)ꢀ
C(47)ꢀ
C(57)ꢀ
C(39)ꢀ
C(42)ꢀ
C(48)ꢀ
C(46)ꢀ
/
H(33). . .O(1)
/
/
H(43). . .O(1) a
H(47). . .O(2) b
H(57). . .O(2) b
H(39). . .O(21) c,d
H(42). . .O(22) e
H(48). . .O(211) f,g
H(46). . .O(211) f,g
/
/
/
˚
/
/
/
˚
˚
2.115 A found for H2O and 2.022Á2.075 A found for the
/
/
O-bonded anions mentioned above. The geometry of the
two independent OPOF2ꢁ anions is that previously
/
a
Symmetry transformations used to generate equivalent atoms:
found [13] and it exhibits an enlargement of the Oꢀ
/
Pꢀ
/
xꢁ
/
1, y, z.
Symmetry transformations used to generate equivalent atoms:
O angle and a contraction of the FꢀPꢀF angle in
/
/
b
relation to the ideal tetrahedral value of 109.58 in
accordance with the VSEPR rules [20]. Due to a
disorder, the geometry of the OPOF2ꢁ group attached
to Rh(1) is somewhat distorted. All the four indepen-
dent PPh3 groups show significant deviations from
xꢂ
/
1, y, z.
Occupancy: 0.23.
Symmetry transformations used to generate equivalent atoms:
c
d
xꢂ
/
1, yꢂ
/
1, z.
Symmetry transformations used to generate equivalent atoms:
1, yꢁ1/2, ꢁz.
e
ꢁ
/
xꢂ
/
/
/
cylindrical symmetry about the Rhꢀ
can be seen from Fig. 1. Although the mean values of
the PꢀC bond distances and the RhꢀPꢀC and CꢀPꢀ
/PPh3 bond axis, as
f
Occupancy: 0.77.
Symmetry transformations used to generate equivalent atoms:
g
/
/
/
/
/C
ꢁ
/
x, yꢂ
/
1/2, ꢁ
/
zꢂ1.
/
˚
angles for each of the four groups (1.825(5) A, 1148 and
1058, respectively) are as expected, there exist consider-
able variations in the angular parameters, the Rh(2)ꢀ
/
cular ones, which involve the terminal O atom (O(21),
O(211), and O(22)). It should be noted that the
arrangement of the anion bonded to Rh(2) causes
more repulsion in the molecule as indicated by deforma-
tions of bond lengths and angles being larger at Rh(2)
than at Rh(1). Therefore, the conformation of the
complex molecule containing Rh(2), as probably forced
by intermolecular interactions, should not be retained in
a solution.
An interesting feature of the crystal structure is the
presence of an approximate center of symmetry at about
0.23, 0.73, and 0.26, which relates more exactly the
coordinates of the interior portions of the two complex
molecules than the external portions. These molecules
P(5)ꢀ
/
C angles being the largest at 101.2(1)Á120.3(1)8.
/
The only remarkable differences between the chemi-
cally equivalent bond lengths in the two complex
molecules are those in the Rhꢀ
/
P bond lengths (a
statistically significant difference is observed for two
˚
P bond lengths of 2.3269(9) and 2.3430(7) A),
Rh(2)ꢀ
/
whereas significant conformational and angular differ-
ences make the two molecules considerably different, in
spite of general similarities. The most striking difference
between the two molecules concerns the arrangement of
the OPOF2ꢁ anion with respect to the coordination core
of each molecule, evident from the values of the Rhꢀ
P angles (154.1(2)8 for Rh(1) and 162.1(1)8 for Rh(2))
and from the values of the RhꢀOꢀPꢀO torsion angles
(ca. ꢁ1608 and ꢂ1208, respectively, for the main and
/
Oꢀ
/
/
/
/
are arranged in such a way that the Cꢀ/H bond of one
/
/
phenyl ring from each molecule points towards the Rh
atom of the other molecule. The Rh. . .H lines are nearly
minor components of Rh(1) and 838 for Rh(2)). This is
connected with a different pattern of intra- and inter-
perpendicular to the ligand coordination mean plane,
˚
but the relevant distances of 3.03Á3.17 A are rather long
molecular Cꢀ
/
H. . .O hydrogen bonds in which the two
oxygen atoms of each OPOF2ꢁ anion participate (see
Table 2). The intramolecular hydrogen bonds are
depicted in Fig. 1. It seems that, while the rotation of
/
for Cꢀ
/
H. . .Rh hydrogen bonds. However, an approach
of pseudo-symmetry-related molecules causes steric
interactions between their phenyl groups and is respon-
sible for the bending of the phosphine groups away from
the anion about the RhꢀO bond is restricted by the
intramolecular hydrogen bonds involving the O atom
/
the adjacent molecule and for distortions of the Rhꢀ
/
Pꢀ
/
(O(11) or O(12)) bonded to the Rh atom, its orientation
P bond depends rather on the intermole-
about the Oꢀ
/
C angles. Adjacent pairs of non-equivalent molecules

A.M. Trzeciak et al. / Inorganica Chimica Acta 350 (2003) 339Á
/346
343
are joined by Cꢀ
/
H. . .O interactions involving OPOF2ꢁ
Table 3
Selected 31P NMR (J(Rhꢀ
(P(OPh)3)3]Y, [Rh(P(OPh)3)4]Y, and RhX(P(OPh)3)3 in CDCl3
/
P), Hz) data of complexes [Rh(CO)
anions and carbonyl ligands.
Y or X
PF6
CF3SO3 200.0; 217.0
[Rh(CO)(P(OPh)3)3]Y [Rh(P(OPh)3)4]Y RhX(P(OPh)3)3
199.3; 222.0 213.6
2.3. Reactions of HRh(CO)(P(OPh)3)3 and
HRh(P(OPh)3)4 complexes with AgY salts (Yꢀ
PF6ꢁ,
/
CF3SO3ꢁ, BF4ꢁ)
BF4
200.8; 220.6
Cl [22]
NCS [22]
CN [22]
224.0; 285.0
220.6; 266.2
225.3; 224.2
The IR spectrum of the HRh(CO)(P(OPh)3)3 starting
complex in CH2Cl2 solution contains an intense n(CO)
band at 2056 cmꢁ1 and a broad band at approximately
1970 cmꢁ1 assigned to n(Rhꢀ
/H). After Ag(I) salt
of [Rh(P(OPh)3)4]ClO4 in CH2Cl2 saturated with CO
and consistent with the presence of the
[Rh(CO)2(P(OPh)3)3]ꢂ cation [22].
The exchange of P(OPh)3 and CO ligands in the
coordination sphere of rhodium can easily be monitored
by IR or UVÁ
transformation
[Rh(P(OPh)3)4]PF6 in the presence of free P(OPh)3
(reaction (6)) is quantitative and accompanied by the
disappearance of n(CO) in the IR spectrum as well as by
addition, first a new n(CO) band appeared at 2075
cmꢁ1, and then shifted to 2083 cmꢁ1. At the same time,
changes in the region of n(Rhꢀ
/
H) frequencies were
observed; the initial band at 1970 cmꢁ1 was shifted to
1965 cmꢁ1 and became narrow and more intense. These
changes, as well as precipitation of silver metal, suggest
the formation of the [HRh(CO)(P(OPh)3)3]ꢂ complex,
which was confirmed by the ESR spectrum measured in
frozen CH2Cl2 solution. This ESR spectrum, similar to
that reported for [HRh(CO)(PPh3)3]ꢂ [4], is consistent
with the square-pyramidal structure of complex with an
apical phosphorus ligand. The values of hyperfine
/
Vis spectroscopy. For example, the
of [Rh(CO)(P(OPh)3)3]PF6 to
the shift of the absorption band in UVÁ
382 nm:
/
Vis from 396 to
coupling constants for phosphorus are A1ꢀ
/
332 G,
P(OPh)3
[Rh(CO)(P(OPh)3)3]ꢂ 0 [Rh(P(OPh)3)4]ꢂ ꢂCO (6)
A2ꢀ
/
324 G, and A3ꢀ
/
364 G, and are remarkably higher
than those observed for [HRh(CO)(PPh3)3]ꢂ, reflecting
the weaker basicity of P(OPh)3 compared with that of
PPh3 [21].
The reaction of the hydrido complex HRh(P(OPh)3)4
with AgPF6 was performed for comparison with above-
studied reactions. The ESR measurement of the frozen
reaction solution containing 1 equiv. of silver per
rhodium confirmed the formation of an Rh(II) complex,
[HRh(P(OPh)3)4]ꢂ, with square-pyramidal symmetry.
The spectrum presented two sets of lines with para-
meters very similar to those for [HRh(CO)(P(OPh)3)3]ꢂ.
The final reaction product, [Rh(P(OPh)3)4]PF6, was
The [HRh(CO)(P(OPh)3)3]Y intermediate species de-
composed with H2 evolution to [Rh(CO)(P(OPh)3)3]Y
(Yꢀ
/
PF6ꢁ, BF4ꢁ, CF3SO3ꢁ) complexes, which have been
isolated and characterized (reaction (5)):
identified by means of 31P NMR (dꢀ
105.4 ppm,
/
ð5Þ
Following this reaction pattern, one may observe
significant difference in reactivity of [Rh(CO)L3]ꢂ
cationic complexes with PPh3 and P(OPh)3 ligands
(compare reaction (1) with reaction (5)).
Complexes of [Rh(CO)(P(OPh)3)3]Y formula pre-
sented 31P NMR spectra with the typical A2BX pattern
(A, Bꢀ31
/
P; Xꢀ103
/
Rh) with parameters practically
independent on the kind of anion Y. The difference
P) coupling constant values is
between the two J(Rhꢀ
/
equal (ca. 20 Hz) and is smaller than that in the 31P
NMR spectra of RhX(P(OPh)3)3 complexes (Table 3)
[22]. An intense n(CO) band was observed at 2083 cmꢁ1
(in KBr and in CH2Cl2). When CH2Cl2 solution of
[Rh(CO)(P(OPh)3)3]PF6 was saturated with CO, the
second CO ligand was coordinated to rhodium and
second intense n(CO) band appeared at 2032 cmꢁ1. This
spectrum was identical with that obtained for a solution
Scheme 2.

344
A.M. Trzeciak et al. / Inorganica Chimica Acta 350 (2003) 339Á346
/
J(Rhꢀ
/
P)ꢀ
/
213.6 Hz) and UVÁ
/
Vis spectra, close to
4.2.3. [Rh(CO)(PPh3)2(H2O)]PF6
Complex was obtained as above using 0.064 g (2.5ꢃ
10ꢁ4 mol) of AgPF6 and 0.22 g (2.4ꢃ10ꢁ4 mol) of
HRh(CO)(PPh3)3. 31P NMR (CDCl3; d, ppm) 26.0, d,
J(RhꢀP)ꢀ125.1 Hz; ꢁ146.9, J(PꢀF)ꢀ714 Hz (PF6);
IR (KBr; cmꢁ1): 1997 vs (n(CO)), 850 (PF6); UVÁ
Vis
655
those of the analogous complexes, [Rh(P(OPh)3)4]ClO4
and [Rh(P(OPh)3)4]BPh4, respectively (see Scheme 2)
[23].
/
/
/
/
/
/
/
/
3. Conclusions
(CHCl3;
nm)
278,
346;
MS
(m/z):
(Rh(PPh3)2(CO)ꢂ), 627 (Rh(PPh3)2ꢂ).
The HRh(CO)L3 complexes (LꢀPPh3, P(OPh)3) are
/
oxidized with AgY salts to [HRh(CO)L3]ꢂ species,
identified in solution by ESR and IR spectra. These
Rh(II) intermediates decompose with H2 evolution
forming Rh(I) cationic complexes, [Rh(CO)L3]ꢂ. The
[Rh(CO)(PPh3)3]ꢂ complexes exist only in solution and
during isolation procedure at presence of even traces of
water are converted to [Rh(CO)(PPh3)2(H2O)]ꢂ com-
plexes. In contrast, analogous phosphito complexes of
[Rh(CO)(P(OPh)3)3]ꢂ structure are stable and can be
isolated in solid.
4.2.4. Rh(CO)(PPh3)2(OPOF2)
A sample of [Rh(CO)(PPh3)2(H2O)]PF6, approxi-
mately 0.03 g (3.7ꢃ
10ꢁ4 mol), was dissolved in ethanol
(2 ml) and left for crystallization. After 3 days, orange
crystals were obtained. Found: C, 58.06; H, 4.4.
C37H30F2P3O3Rh requires C, 58.75; H, 4.4%. 31P
/
NMR (CDCl3; d, ppm) 25.9, d, J(Rhꢀ
/
P)ꢀ
/
125 Hz;
960 Hz; IR (KBr; cmꢁ1): 1984 vs
ꢁ
/
20.9, t, J(Pꢀ
/
F)ꢀ
/
(n(CO)), 1300 s (n(PO)).
4.2.5. [Rh(CO)(P(OPh)3)3]BF4
To the solution of 0.03 g (1.5ꢃ
in 2 ml of CH2Cl2, 0.11 g (1.0ꢃ
/
10ꢁ4 mol) of AgBF4
10ꢁ4 mol) of
4. Experimental
/
HRh(CO)(P(OPh)3)3 was added and the mixture was
stirred for 30 min. The yellow solution was filtered to
remove silver metal and evaporated to dryness under
vacuum. The resulted pale yellow powder was washed
with methanol and dried. Found: C, 57.35; H, 3.93.
C55H45BF4P3O10Rh requires C, 57.52; H, 3.95%. 31P
4.1. Reactants
The following rhodium complexes HRh(CO)(PPh3)3
[24], HRh(CO)(P(OPh)3)3 [25], and [Rh(P(OPh)3)4]ClO4
were prepared by literature methods [23]. AgPF6 and
Ag(CF3SO3) were purchased from Aldrich and AgBF4
from Avocado Research Chemicals. CH2Cl2 was dis-
tilled from CaH2 and stored under dinitrogen. All
reactions of rhodium complexes with silver salts were
performed under N2 using the standard Schlenk tech-
nique.
NMR (CDCl3; d, ppm) A2BX: 109.6 (PA), J(Rhꢀ
200.8 Hz, 106.7 (PB), J(RhꢀP)ꢀ220.6 Hz, J(Pꢀ
62.1 Hz; IR (KBr; cmꢁ1): 2083 n(CO), 1080 (BF4);
/
P)ꢀ
/
/
/
/
P)ꢀ
/
UVÁVis (CHCl3; nm) 296, 396; MS (m/z): 1033
/
(Rh(P(OPh)3)3ꢂ), 724 (Rh(P(OPh)3)2ꢂ).
4.2. Rhodium complex syntheses and identification
4.2.6. [Rh(CO)(P(OPh)3)3]CF3SO3
Complex was obtained as above using 0.05 g (2.0ꢃ
/
10ꢁ4 mol) of Ag(CF3SO3) and 0.18 g (1.7ꢃ10ꢁ4 mol)
/
4.2.1. [Rh(CO)(PPh3)2(H2O)]BF4
To the solution of 0.03 g (1.5ꢃ
/
10ꢁ4 mol) of AgBF4
10ꢁ4 mol) of
of HRh(CO)(P(OPh)3)3 in 4 ml of CH2Cl2. The yellow
powder obtained was washed with methanol and dried.
Found: C, 55.36; H, 3.43. C56H45F3SP3O13Rh requires
C, 55.55; H, 3.75%. 31P NMR (CDCl3; d, ppm) A2BX:
in 3 ml of CH2Cl2, 0.10 g (1.1ꢃ
/
HRh(CO)(PPh3)3 was added and the mixture was stirred
for 15 min. The dark reddish-brown solution was
filtered to remove precipitate of silver metal and
evaporated to dryness under vacuum. The yellowish-
brown solid was washed with ethyl ether and dried.
31P NMR (CDCl3; d, ppm) 26.3, J(Rhꢀ
Hz; IR (KBr; cmꢁ1): 1993 vs (n(CO)), 1100 (BF4),
113.0 (PA), J(Rhꢀ
217.0 Hz, J(PꢀP)ꢀ
/
P)ꢀ
/
200.0 Hz, 110.0 (PB), J(Rhꢀ
/
P)ꢀ
/
/
/
63 Hz; IR (KBr; cmꢁ1): 2083
n(CO), 1080 (BF4); UVÁVis (CHCl3; nm) 296, 396;
/
/
P)ꢀ
/
128.2
MS (m/z): 1033 (Rh(P(OPh)3)3ꢂ), 724 (Rh(P(OPh)3)2ꢂ).
CH2Cl2: 1998; UVÁVis (CHCl3, nm) 274, 348; MS (m/
/
z): 655 (Rh(PPh3)2(CO)ꢂ), 627 (Rh(PPh3)2ꢂ).
4.2.7. [Rh(CO)(P(OPh)3)3]PF6
Complex was obtained as above using 0.05 g (2.0ꢃ
/
10ꢁ4 mol) of AgPF6 and 0.18 g (1.7ꢃ10ꢁ4 mol) of
/
4.2.2. [Rh(CO)(PPh3)2(H2O)]CF3SO3
Complex was obtained following above procedure
HRh(CO)(P(OPh)3)3. The pale yellow powder obtained
was washed with methanol and dried. Found: C, 54.45;
H, 3.13. C55H45F6P4O10Rh requires C, 54.74; H, 3.76%.
using 0.04 g (1.6ꢃ
(1.1ꢃ
10ꢁ4 mol) of HRh(CO)(PPh3)3. 31P NMR
(CDCl3; d, ppm) 29.8, d, J(RhꢀP)ꢀ124.0 Hz; IR
(KBr; cmꢁ1): 1993 vs, 2011 s (n(CO)), CH2Cl2: 1998.
/
10ꢁ4 mol) of AgCF3SO3 and 0.1 g
/
31P NMR (CDCl3; d, ppm) A2BX: 109.6 (PA), J(Rhꢀ
P)ꢀ199.3 Hz, 106.7 (PB), J(RhꢀP)ꢀ222 Hz, J(Pꢀ
/
/
/
/
/
/
/

A.M. Trzeciak et al. / Inorganica Chimica Acta 350 (2003) 339Á
/346
345
P)ꢀ
/
61.8 Hz; ꢁ
/
147, J(Pꢀ
/
F)ꢀ
/
714 Hz (PF6); IR (KBr;
Vis (CHCl3; nm)
large and directional for the O(21) and F(41) atoms of
the disordered group and for the atoms of the phenyl
ring C(16)ꢀC(56), neighboring to this group. The
hydrogen atoms were included in calculated positions
cmꢁ1): 2085 n(CO), 840 (PF6); UVÁ
/
296, 396; MS (m/z): 1033 (Rh(P(OPh)3)3ꢂ), 724
(Rh(P(OPh)3)2ꢂ).
/
˚
H: 0.95 A) with isotropic displacement parameters
set at 1.2Ueq of the bonded carbon atom. Scattering
(Cꢀ
/
4.2.8. [Rh(P(OPh)3)4]PF6
Complex was obtained as above using 0.012 g (4.8ꢃ
/
factors were taken from Ref. [30].
Crystal data: C37H30F2O3P3Rh, Mꢀ756.43, mono-
10ꢁ5 mol) of AgPF6 and 0.05 g (3.7ꢃ10ꢁ5 mol) of
/
/
˚
˚
15.198(3) A,
clinic, space group P21, aꢀ
/
9.914(3) A, bꢀ
98.89(3)8, Vꢀ
0.709 mmꢁ1, F(000)ꢀ
/
HRh(P(OPh)3)4. The pale yellow product was obtained
by evaporation to dryness of the reaction solution after
separation of silver metal. Found: C, 54.25; H, 3.13.
C55H45F6P4O10Rh requires C, 54.74; H, 3.76%. 31P
3
˚
˚
cꢀ
4, Tꢀ
/
22.228(4) A, bꢀ
/
/
3308.9(13) A , Zꢀ
/
/
100(2) K, mꢀ
/
/
1536, 53 110
reflections measured, 17 190 unique (Rint
wR2(F2)ꢀ
0.0493 (all data), R1ꢀ0.0290 [I ꢀ
Sꢀ1.006.
ꢀ
/
0.034),
2s(I)],
/
/
/
NMR (CDCl3; d, ppm): 105.4, d, J(Rhꢀ
Hz, ꢁ146.9, J(PꢀF)ꢀ711 Hz (PF6); UVÁVis (CHCl3;
nm) 294, 382.
/
P)ꢀ
/
213.6
/
/
/
/
/
4.4. Measurements
UVÁVis spectra have been measured on Hewlett-
Packard 8452 Diode Array spectrometer, IR spectra
were recorded on Nicolet Impact 400, and NMR spectra
on Bruker 300 spectrometers. ESR spectra have been
measured on Electron Spin Resonance ESP 300 E
Bruker spectrometer.
4.2.9. ESR data of Rh(II) complexes in CH2Cl2 solution
[HRh(CO)(P(OPh)3)3]ꢂ (77 K): g1ꢀ
2.23, g2ꢀ2.195,
g3ꢀ2.118; A(Pap)1ꢀ332 G, A(Pap)2ꢀ324 G,
A(Pap)3ꢀ364 G (the hyperfine couplings were not
determined because of poor resolution of the spectrum).
[HRh(P(OPh)3)4]ꢂ (77 K): g1ꢀ
2.23, g2ꢀ2.20, g3ꢀ
2.13; A(Pap)1ꢀ337 G, A(Pap)2ꢀ326 G, A(Pap)3ꢀ373
/
/
/
/
/
/
/
/
/
/
/
/
/
G (the hyperfine couplings were not determined because
of poor resolution of the spectrum).
Acknowledgements
4.3. Crystal structure determination
We are indebted to Prof. Armando Pombeiro for
helpful discussion. Grant No. PBZ-KBN 15/09/T09/99/
01d is gratefully acknowledged.
Diffraction data were collected on a Kuma KM4CCD
area detector diffractometer (v-scan) with graphite-
˚
0.71073 A,
monochromated Mo Ka radiation (lꢀ
/
from a crystal of dimensions approximately 0.25
mmꢃ0.25 mmꢃ0.10 mm). 53 110 reflections (17 191
unique) were measured to 2Uꢀ608 (h: ꢁ13013, k: ꢁ
21019, l: ꢁ29031). The numerical, face indexed,
correction for absorption was applied (Tmin 0.824,
Tmax 0.925 [26]). The structure was solved using direct
/
/
References
/
/
/
/
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