Synthetic routes and structures of [Rh(Hdmg){ClZn(C2H 5OH)dmg}(PPh3)Cl], [Rh(Hdmg)2(PPh) 2]+[Rh(Hdmg)2(Cl)2] -·2CH3OH, and [Rh(Hdmg)2(PPh3)I]· 0.5C2H5OH complexes

Article abstract of DOI:10.1016/S0277-5387(03)00468-6

Treatment of [Rh(Hdmg)₂(PPh₃)Cl] with zinc amalgam afforded a heterobimetallic compound [Rh(Hdmg)(ClZndmg)(PPh₃)Cl] (1a) (Hdmg=monoanion of dimethylglyoxime). Crystallization of (1a) from a CHCl ₃/C₂H₅OH mixture led to the formation of [Rh(Hdmg){ClZn(C₂H₅OH)dmg}(PPh₃)Cl] (1). The X-ray crystal structure of 1 revealed that the ethanol molecule was built into the complex molecule through the oxygen atom coordinated to the zinc cation and a hydrogen bond involving one of the chloride ligands. Reduction of [Rh(Hdmg)₂(PPh₃)Cl] with Zn/Hg, followed by treatment with a CHCl₃/CH₃OH mixture, gave the complex salt [Rh(Hdmg)₂(PPh₃)₂]⁺[Rh(Hdmg) ₂(Cl)₂]^- · 2CH₃OH (2). The X-ray structure of 2 showed crystals formed by cations [Rh(Hdmg) ₂(PPh₃)₂]⁺ and anions [Rh(Hdmg) ₂Cl₂]^-. The anion binds one CH₃OH molecule through a hydrogen bond involving the adjacent oxime atom. Reduction of [Rh(Hdmg)₂(PPh₃)Cl] with zinc amalgam in the presence of CH₃I led to the compound [Rh(Hdmg)₂(PPh₃)I] · 0.5C₂H₅OH (3), which was characterized by X-ray crystallography.

Full text of DOI:10.1016/S0277-5387(03)00468-6

Polyhedron 22 (2003) 3195–3203
www.elsevier.com/locate/poly
Synthetic routes and structures
of [Rh(Hdmg){ClZn(C2H5OH)dmg}(PPh3)Cl],
[Rh(Hdmg)2(PPh)2]þ[Rh(Hdmg)2(Cl)2]ꢀ ꢁ 2CH3OH,
and [Rh(Hdmg)2(PPh3)I] ꢁ 0.5C2H5OH complexes
*
ꢀ
ꢀ
Monika Moszner , Zbigniew Ciunik, Jozef J. Ziołkowski
Faculty of Chemistry, University of Wrocław, ul., 14 F. Joliot-Curie Street, PL-50383 Wrocław, Poland
Received 7 April 2003; accepted 14 July 2003
Abstract
Treatment of [Rh(Hdmg)2(PPh3)Cl] with zinc amalgam afforded a heterobimetallic compound [Rh(Hdmg)(ClZndmg)(PPh3)Cl]
(1a) (Hdmg ¼ monoanion of dimethylglyoxime). Crystallization of (1a) from a CHCl3/C2H5OH mixture led to the formation of
[Rh(Hdmg){ClZn(C2H5OH)dmg}(PPh3)Cl] (1). The X-ray crystal structure of 1 revealed that the ethanol molecule was built into the
complex molecule through the oxygen atom coordinated to the zinc cation and a hydrogen bond involving one of the chloride ligands.
Reduction of [Rh(Hdmg)2(PPh3)Cl] with Zn/Hg, followed by treatment with a CHCl3/CH3OH mixture, gave the complex salt
[Rh(Hdmg)2(PPh3)2]þ[Rh(Hdmg)2(Cl)2]ꢀ ꢁ 2CH3OH (2). The X-ray structure of
2 showed crystals formed by cations
[Rh(Hdmg)2(PPh3)2]þ and anions [Rh(Hdmg)2Cl2]ꢀ. The anion binds one CH3OH molecule through a hydrogen bond involving the
adjacent oxime atom. Reduction of [Rh(Hdmg)2(PPh3)Cl] with zinc amalgam in the presence of CH3I led to the compound
[Rh(Hdmg)2(PPh3)I] ꢁ 0.5C2H5OH (3), which was characterized by X-ray crystallography.
Ó 2003 Elsevier Ltd. All rights reserved.
Keywords: Rhodium; Rhodoximes; Oximates; Spectral properties; Crystal structures
1. Introduction
A good number of six-coordinate rhodoximes
[Rh(Hdmg)2LX] (Fig. 1a) have already been studied
[2,3,7]. Some metal complexes with planar, tetradentate
chelating ligands are able to form different adducts. The
bridging hydrogen ofthe equatorial O –Hꢁ ꢁ ꢁO groups can
be substituted by metal ions (Fig. 1b). Although many
polynuclear transition metal complexes of that kind are
known for Co [8] and Cu [9], very few products resulting
from OH hydrogen substitution in rhodoximes have been
reported. Ramasami and Espenson [10] described the
synthesis of [ClRh(BF2dmg)2(PPh3)], and Espenson and
McHatton [11] showed that [CH3Rh (Hdmg)(H2O)] re-
acts reversibly with Fe(H2O)36þ with the formation of the
The coordination environments of metal ions in
biomolecules often consist of nitrogen donor atoms.
Complexes of rhodium with the tetradentate equatorial
ligand bisdimethylglyoximate (Hdmg)2, called rhodoxi-
mes, are interesting analogues of cobaloximes, which are
often considered to be models of vitamin B12 coenzyme
[1]. Reactions of rhodoximes with alkyl halides are of
considerable interest [2], as they contribute to a better
understanding of the mechanistic and kinetic behaviour
of these compounds [3]. Some rhodoximes have dem-
onstrated very promising catalytic properties in hydro-
genation [4a–4d], hydroformylation [4d], hydrosililation
[5], and oxidation [6] reactions.
cation [CH3Rh(Hdmg)(Fedmg) (H2O)]2þ
.
In a previous paper we described the synthesis of the
tetranuclear bimetallic compound [Rh(Hdmg)(ClZn
dmg)(PPh3)]2 featuring a Rh(II)–Rh(II) bond [12]. The
interest in homo- and heterobimetallic complexes has
recently increased, as the reactivity and properties of the
* Corresponding author. Tel.: +48-71-3757-228; fax: +48-71-328-23-
48.
E-mail address: mm@wchuwr.chem.uni.wroc.pl (M. Moszner).
0277-5387/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/S0277-5387(03)00468-6

3196
M. Moszner et al. / Polyhedron 22 (2003) 3195–3203
L
(b)
(a)
L
CH3
C
H O
N
CH3
C
C
H O
N
C
O
N
O
N
CH3
N
N
Rh
CH3
C
H3C
N
N
Rh
C
H3C
O
O
C
C
O
X
H3C
O
X
H3C
M
H
Fig. 1. (a) [Rh(Hdmg)2XL] complexes, (b) [Rh(Hdmg)(Mdmg)XL].
metal core may be strongly modified by the presence of
another metallic centre in close proximity. Two bonded or
closely neighbouring non-bonded metal atoms may react
with substrate molecules in a cooperative manner [13].
In this paper, based on the work we have carried out
in this field, we report the synthesis and characterization
of the first bimetallic complexes containing Rh(III) and
Zn(II) centres, [Rh(Hdmg)(ClZndmg)(PPh3)Cl] (1a) and
its interesting ethanolic adduct [Rh(Hdmg){ClZn(C2
H5OH)dmg}(PPh3)Cl] (1). The complex salt [Rh
(Hdmg)2(PPh3)2]þ[Rh(Hdmg)2(Cl)2]ꢀ ꢁ 2CH3OH (2) was
isolated from the reaction mixture by treatment with the
CHCl3/CH3OH solution. The simultaneous action of
Zn/Hg and CH3I on [Rh(Hdmg)(PPh3)Cl] resulted in the
compound [Rh(Hdmg)2(PPh3)I] ꢁ 0.5 C2H5OH (3).
[Rh(Hdmg)2(PPh3)I] was obtained for the first time by
Powell in a reaction of RhCl3 ꢁ 3H2O pretreated with KI
before the addition of dimethylglyoxime and PPh3 [7d],
but was not characterized in detail then.
techniques unless stated otherwise. [Rh(Hdmg)2(PPh3)
Cl] was prepared according to the procedure of Powell
[7d].
The syntheses of compounds 1a, 1, 2, and 3 followed
the same initial procedure. A three-neck glass reactor
equipped with a magnetic stirring bar, a reflux con-
denser connected to a mineral oil bubbler, a fritted
glass inlet tube, and a dropping funnel was charged
with [Rh(Hdmg)2(PPh3)Cl] (0.104 g, 0.16 mmol) and
then deaerated in 10 vacuo/N2 cycles. Subsequently 40
cm3 of absolute ethanol (degassed) was added and the
reaction mixture was heated at 55 °C until
[Rh(Hdmg)2(PPh3)Cl] dissolved. Then the heating was
stopped and Zn(Hg) beads (1%, 10 g) were added.
After about 40 min of stirring a suspension of pink-
yellow solid A in a brown-orange solution B was
formed.
2.2.1. [Rh(Hdmg)(ClZndmg)(PPh3)Cl] (1a)
After filtration, the solid A, contaminated with a
reddish impurity, was further washed with a small
amount of cold degassed dichloromethane and taken to
dryness to give a pale yellow precipitate. Yield 47 mg,
40%. Anal. Calc. for C26H28N4P1O4Cl2ZnRh
(M ¼ 730:66): C, 42.74; H, 3.86; N, 7.70. Found: C,
42.84; H, 3.85; N, 7.60%. Selected IR frequencies
(KBr), cmꢀ1: mCN 1564 (s), mNO 1234. NMR spectra
2. Experimental
2.1. Materials and measurements
RhCl3 ꢁ 3H2O was purchased from Pressure Chemical
Co. All other chemicals were of reagent grade and were
used in the commercially available form. UV–Vis spectra
were monitored in the 200–820 nm range with a Hewlett
Packard 8452A rapid scan diode array spectrometer.
Infrared spectra were recorded on an FT-IR Nicolet
Impact 400 spectrometer in the 4000–400 cmꢀ1 range as
KBr disks or Nujol mulls. The NMR spectra were mea-
sured on a Bruker AMX-300 spectrometer (1H at 300.13
MHz, 31P at 121.496 MHz) with TMS as internal stan-
1
(CDCl3), H: 15.64 (brs, O–Hꢁ ꢁ ꢁO), 7.43–7.28 (m, 15,
P(C6H5)3), 2.07 (s, 6, CH3); 1.76 (s, 6, CH3), 31P{H}:
1
25.3 ppm (d, JRh–P ¼ 122 Hz).
2.2.2. [Rh(Hdmg){ClZn(C2H5OH)dmg}(PPh3)Cl] (1)
Slow, multiple crystallization of 1a from the CHCl3/
EtOH mixture led to red-gold, X-ray quality crystals of
1. Anal. Calc. for C28H34N4P1O5Cl2ZnRh (M ¼ 776:73):
C, 43.29; H, 4.41; N, 7.21; P, 3.98. Found: C, 43.39; H,
4.38; N, 7.4; P, 3.89%. Selected IR absorption bands
(KBr), cmꢀ1: mCN 1570 (s); mNO 1238 (vs). NMR spectra
(CDCl3), 1H d: 17.64 (brs, 1, OH), 13.3 (s, 1, OH), 7.43–
7.28 (m, 15, P(C6H5)3), 3.85 (qt, J ¼ 7:2 Hz, 2, CH2
(C2H5OH)); 1.96 (s, 6, CH3); 1.91 (s, 6, CH3), 1.28 ppm
(t, J ¼ 7:2 Hz, 3, CH3 (C2H5OH)); 31P{P}: 25.9 ppm (d,
1JRh–P ¼ 125 Hz).
1
dard and 85% H3PO4 as external standard for H and
31P{H}, respectively. Elemental analyses were performed
at the Elemental Analysis Centre, Wrocław University,
on a Perkin–Elmer Elemental Analyser 2400 for CHN.
2.2. Syntheses
All manipulations were performed under anaerobic
conditions using standard Schlenk or vacuum line

M. Moszner et al. / Polyhedron 22 (2003) 3195–3203
3197
2.2.3. [Rh(Hdmg)2(PPh3)2]þ[Rh(Hdmg)2(Cl)2]ꢀ ꢁ
2CH3OH (2)
absorption bands (KBr), cmꢀ1: mCN 1532 (w), mNO 1258
(s). NMR spectra (CDCl3): 1H, 7.48–7.36 (m, 15, PPh3),
1.86 (s, 12, CH3 (Hdmg)); 31P: 16.34 ppm (d,
1JRh–P ¼ 112 Hz).
The filtrate B was evaporated under vacuum. Disso-
lution of the crude solid in CHCl3 over time yielded a
sandy solid, which was filtered off and dried in vacuo.
Crystallization from CH3OH gave pale yellow crystals
of 2. Yield 42 mg, 20%. Anal. Calc. for C54H66N8P2
O10Cl2Rh2 (M ¼ 1325:8): C, 48.92; H, 5.02; N, 8.45.
Found: C, 48.46; H, 5.23; N, 8.22%. Selected IR fre-
quencies (KBr), cmꢀ1: mCN 1537 (s), mNO 1257 (vs). NMR
2.3. X-ray structure determination
Crystal data are given in Table 1, together with re-
finement details. All measurements of crystals 1, 2, and 3
were performed on a Kuma KM4CCD j-axis diffrac-
tometer with graphite-monochromated Mo Ka radia-
tion. Crystals were positioned at 65 mm from the
KM4CCD camera. 612 frames were measured at 0.75°
intervals with a counting time of 15–30 s. The data were
corrected for Lorentz and polarization effects. Absorp-
tion correction based on least-squares fitted against
jFcj ꢀ jFoj differences was applied for 1 and 3. Data re-
duction and analysis were carried out using the Kuma
Diffraction (Wrocław) programs [14]. The structure was
solved by the heavy atom method (SHELXS 97 program
[15]) and refined by the full-matrix least-squares method
on all F 2 data using the SHELXL 97 programs [16]. Non-
hydrogen atoms were refined with anisotropic displace-
ment parameters; hydrogen atoms were included from
the geometry of molecules and Dq maps; they were not
refined for 1 and were refined with isotropic thermal
parameters for 2 and 3.
1
spectra (CD3OD), H d: 7.53–7.37 (m, 30, P(C6H5)3),
2.31 (s, 12, CH3 (Hdmg)), 1.34 ppm (brs, 12 (Hdmg));
1
31P: 18.51 ppm (d, JRh;P ¼ 90:17 Hz). (CD2Cl2), 1H:
7.31–7.18 (m, 30, P(C6H5)3), 2.27 (s, 12, CH3 (Hdmg)),
5
1.42 ppm (t, JP;H ¼ 1:34 Hz, 12 (Hdmg)); 31P: 16.94
1
ppm (d, JRh;P ¼ 91 Hz).
2.2.4. [Rh(Hdmg)2(PPh3)I] ꢁ 0.5C2H5OH (3)
On addition of CH3I to the filtrate B the resulting
mixture was stirred overnight at room temperature un-
der nitrogen. The orange solution was evaporated to
give a thick, syrupy liquid. This liquid was redissolved in
a THF/EtOH mixture and left to stand in dark until
brown-reddish micro-crystals appeared. They were col-
lected by filtration, washed with ethanol, and dried in
vacuo. Yield 24 mg, 20%. Anal. Calc. for
C27H32N4PO4:5IRh (M ¼ 745:36): C, 43.51; H, 4.33; N,
7.52. Found: C, 43.51; H, 4.41; N, 7.74%. Selected IR
Table 1
Crystal and collection parameters for [Rh(Hdmg){ClZn(C2H5OH)dmg}(PPh3)Cl] (1), [Rh(Hdmg)2(PPh3)2]þ[Rh(Hdmg)2(Cl)2]ꢀ ꢁ 2CH3OH (2), and
[Rh(Hdmg)2(PPh3)I] ꢁ 0.5C2H5OH (3)
1
2
3
Empirical formula
Formula weight
T (K)
C
28H34N4PO5Cl2ZnRh
C54H66N8P2O10 Cl2Rh2
1325.81
100(2)
C26H29N4PO4IRh ꢁ 0.5C2H5OHꢁ
776.74
200(1)
745.35
100(2)
ꢁ
k (A)
0.71073
triclinic
ꢂ
P1
0.71073
triclinic
ꢂ
P1
0.71073
monoclinic
P21/n
Crystal system
Space group
ꢁ
a (A)
10.946(2)
11.619(2)
13.420(3)
112.04(3)
90.02(3)
10.4681(9)
10.6195 (11)
14.7188(12)
91.051(7)
100.431(7)
118.166(10)
1408.4(2)
1
11.5142(9)
14.5389(10)
16.8520(13)
ꢁ
b (A)
ꢁ
c (A)
a (°)
b (°)
c (°)
91.724(7)
93.19(3)
3
ꢁ
V (A )
1579.2(5)
2
1.634
2819.8(4)
4
1.756
Z
Dc (Mg mꢀ3
)
1.563
0.802
680
l (mmꢀ1
F ð000Þ
)
1.545
788
1.799
1484
Crystal size (mm)
h range for data collection (°)
Reflections collected
0.30 ꢂ 0.20 ꢂ 0.20
3.39–28.75
11,292
0.19 ꢂ 0.14 ꢂ 0.14
3.45–28.47
9788
0.18 ꢂ 0.12 ꢂ 0.12
3.51–28.70
19,833
Independent reflections (Rint
Data/parameters
)
7161 (0.0208)
7161/379
0.6543/0.7475
1.039
6189 (0.0282)
6180/488
6715 (0.0308)
6715/468
0.7378/0.8130
1.099
Absorption corrections min./max.
Goodness-of-fit (F 2)
Final R1=wR2 indices (I > 2rI)
Largest differential peak/hole (e A
1.070
0.0260/0.0634
0.752/)0.867
0.0346/0.0825
1.201/)0.750
0.0471/0.1038
1.416/)1.940
ꢀ3
ꢁ
)

3198
M. Moszner et al. / Polyhedron 22 (2003) 3195–3203
3. Results and discussion
The NMR spectra of the evaporated filtrate B, dis-
solved in CDCl3, showed it to contain mainly unreacted
[Rh(Hdmg)2(PPh3)Cl] and small amounts of both 1a
and [Rh(Hdmg)(ClZndmg)(PPh3)]2. The filtrate B also
contained traces of finely dispersed Zn/Hg. B was found
to react with CHCl3 (CDCl3) to form an inner salt
[Rh(Hdmg)2(PPh3)2]þ[Rh(Hdmg)2(Cl)2]ꢀ ꢁ 2CH3OH (2).
Although salts of this kind are well known for the re-
lated cobaloximes [17], only sparse data are available
for rhodoximes [7a,7b,18,19]. The formation of the
cobalt analogues has been found to be catalysed by
Co(II) [17]. It is reasonable to suppose that the same
mechanism can operate in the case of the presented
reactions.
The reaction of the solution B with CH3I, which af-
forded the compound [Rh(Hdmg)2(PPh3)I] ꢁ 0.5C2H5
OH (3), seems to confirm the foregoing. The data pre-
sented here indicate that the interaction between
[Rh(Hdmg)2(PPh3)Cl] and Zn/Hg not only produces the
zinc substituted derivatives, but also unsubstituted
Rh(II) units. The latter are well known to dimerize
rapidly in the absence of other reagents [2g]. It appeared
that the presence of organic as well as inorganic halides
3.1. Synthesis and spectral characterization
For the convenience of the reader the compounds and
reactions are shown in Scheme 1.
A mixture of red and pale yellow precipitates (1:10) is
formed during the first hour of the reaction of
[Rh(Hdmg)2(PPh3)Cl] with zinc amalgam, carried out in
C2H5OH. Based on the 1H and 31P{H} NMR spectra the
red solid was found to be [Rh(Hdmg)(ClZndmg) (PPh3)]2
(1H: 1.2, 1.4, 1.65, 1.72 ppm (CH3 of dmg moieties); 7.2–
7.6 ppm (PPh3); 31P: 3.6 ppm (vt, JRh;P ¼ 97 Hz) [12]).
Combined NMR and elemental analysis data for the
yellow species isolated from this mixture are consistent
with the composition [Rh(Hdmg)(ClZndmg)(PPh3)Cl]
(1a). 1a, containing a coordinatively unsaturated metal
centre (Zn cation), seems to be an intermediate. The
possibility to isolate this by-product and the subsequent
formation of [Rh(Hdmg){ClZn(C2H5OH)dmg}(PPh3)
Cl] (1) upon repeated, slow crystallization from the
CHCl3/C2H5OH mixture may be accounted for by very
low solubility of 1a in ethanol. Unlike in 1a, the presence
of a molecule of ethanol in 1 is well evidenced by the 1H
NMR spectra. In the presence of an excess of Zn/Hg 1
and 1a transform in time into [Rh(Hdmg)(ClZndmg)
(PPh3)]2, being the final product with a yield of 60–70%
[12].
resulted in
a
conversion of the metal radical
[Rh(Hdmg)2PPh3] to rhodium(III) halide abstraction
compounds [2g,2h,20]. Thus it is possible that the same
radical can effect the formation of 2, which can stay in
the equilibrium
[RhII(Hdmg)(ClZndmg)(PPh3)]2
Zn/Hg
(excess)
[RhIII(Hdmg)(ClZndmg)(PPh3)Cl]
Solid A
1a
r.t.
CHCl3/C2H5OH
[RhIII(Hdmg){ClZn(C2H5OH)dmg}(PPh3)Cl]
1
C2H5OH/Zn/Hg (excess)
[RhIII(Hdmg)2(PPh3)Cl]
313K, 1h
Filtrate B
[RhIII(Hdmg)2(PPh3)Cl], traces of Zn/Hg
CHCl3/CH3OH
r.t.
r.t.
CH3I/C2H5OH
[RhIII(Hdmg)2(PPh3)2][Rh(Hdmg)2(Cl)2]x2CH3OH
[RhIII(Hdmg)2(PPh3)I]x0.5C2H5OH
2
3
time
[RhII(Hdmg)(ClZndmg)(PPh3)]2
Scheme 1.

M. Moszner et al. / Polyhedron 22 (2003) 3195–3203
3199
RhðIIÞ
2½RhðHdmgÞ ðPPhÞ Clꢃ ꢀ ½RhðHdmgÞ ðPPh3Þ ꢃ
2
3
2
2
½RhðHdmgÞ Cl2ꢃ
2
The interaction of the Rh(I) species, [Rh(Hdmg)2]ꢀ,
with alkylating agents leads to oxidative addition
products – organorhodoximes [2,21].
The solution B left to stand alone, only in the pres-
ence of traces of Zn/Hg, affords over long time the dimer
[Rh(Hdmg)(ClZndmg)(PPh3)]2.
The 1H resonances of the methyl protons for 1a and 1
are registered as two singlets. This reflects the chemical
inequivalence between the atoms of each dimethylgly-
oximato moiety due to the replacement of one of the
hydrogen bonds by the [ClZn]1þ unit.
The shielding of the equatorial methyls was found to
depend on the number of phosphine phenyls: no PPh3 (d
2.31 ppm for the anion of 2, 2.36 and 2.36–2.47 ppm for
[Rh(Hdmg)(H2dmg)(Cl2)] and [Rh(Hdmg)2(H2O)2]
(ClO4), respectively [7a]); one PPh3 (d 1.99 and 1.91 for 1,
1.86 for 3 and 1.74–1.94 ppm for [Rh(Hdmg)2(PPh3)Cl]
[7a,b]); two PPh3 (d 1.34 for the cation of 2 and 1.38–
1.48 for [Rh(Hdmg)2(PPh3)2](ClO4) [7a]). The singlet at
13.13 ppm in 1 originates from the OH proton of the
bisdimethylglyoximato moiety. An identical value was
observed for [Rh(Hdmg)(ZnCldmg)(PPh3)]2 [12]. The
proton of an OH group at 17.64 ppm in 1 is assigned to
the ethanol molecule coordinated to zinc, forming the
hydrogen bond with Cl bonded to Rh. In both cases,
these signals were registered at room temperature. No
OH proton signal was observed for 2 and 3, which is in
line with the finding that the protons of the O–Hꢁ ꢁ ꢁO
bridges could be observed for the rhodoximes contain-
ing the (Hdmg)2 unit at low temperature. At room
temperature they undergo fast exchange with traces of
water dissolved in the solvent [22].
Fig. 2. Molecular structure of 1.
Selected bond lengths and angles are listed in
Tables 2–4.
The Rh atoms of all the investigated complexes dis-
play a distorted octahedral coordination, with the two
dimethylglyoximate ligands in the equatorial plane and
two other ligands in the axial positions. The average
ꢁ
Rh–N separations are 2.014(2), 1.9942(6), 1.986(4) A for
1, 2, and 3, respectively and are comparable to those
found for the complexes given in Table 5 [2a,7d,17,22].
The Rh–N distances are slightly longer in the cations
than in the anions. The mean N–C distances of 1.294(4),
The 31P NMR spectra show one doublet for each of
the compounds 1a and 1: d 25.3 (1JRh;P ¼ 122 Hz) and d
25.9 ppm (1JRh–P ¼ 125 Hz), respectively. Almost iden-
tical frequencies were registered for [Rh(Hdmg)2PPh3Cl]
(23.8 ppm, 123 Hz) [6]. A doublet at 16.34 ppm with
1JRh–P of 112 Hz in 3 corroborates the X-ray data in-
dicating that the trans-influence of Iꢀ is slightly more
ꢁ
1.302(3), and 1.299(6) A in 1, 2, and 3, respectively are
similar to those found for the complexes cited in Table 5
[2a,7c,18,23]. The Rh–P bond lengths deserve special
ꢁ
attention. The Rh–P distance of 2.4245(5) A in 2 is
distinctly longer than those estimated for 1 and 3,
ꢁ
2.3248(11) and 2.3441(11) A, respectively. The latter
ꢁ
values match the 2.327(1) A bond length reported for
1
pronounced than that of Clꢀ. The JRh;P coupling con-
[Rh(Hdmg)2(PPh3)Cl] [7c]. A comparison of the Rh–P
lengths reveals mutual influence of the trans-coordinated
PPh3 ligands, also demonstrated by the JRh;P couple
constants in 31P NMR spectra, vide supra.
stants of 90.17 and 91 Hz for the doublets at 18.51 and
16.7 ppm registered for 2 and [Rh(Hdmg)2(PPh3)2]
(ClO4) [6], respectively are consistent with the crystal-
lographic data about the apical trans-influence.
The Rh–X axial separations 2.4022(12), 2.3317(5)
ꢁ
(X ¼ Cl for 1 and 2), and 2.6879(5) A, (X ¼ I for 3)
follow the trend of covalent radii, Cl<I and are in line
ꢁ
with those found for [Rh(Hdmg)pyCl], 2.3290(4) A, and
3.2. Crystal structures of 1, 2, and 3
ꢁ
for [Rh(Hdmg)pyI], 2.6423(4) A [2a].
Figs. 2 and 3 show the structures of the complexes
[Rh(Hdmg){CClZn(C2H5OH)dmg}PPh3Cl] (1) and [Rh
(2),
respectively. The molecular structure of [Rh(Hdmg)2
A significant change for H-bonded Hdmg rings was
registered for 1. The distance between O(2) and O(3),
(Hdmg)2(PPh3)2]þ[Rh(Hdmg)2(Cl)2]ꢀ ꢁ 2CH3OH
ꢁ
2.471(3) A, in 1 is distinctly shorter than the distance of
ꢁ
(PPh3)I] ꢁ 0.5 C2H5OH (3) is depicted in Figs. 4 and 5.
2.664(6) A (average) estimated for the Oꢁ ꢁ ꢁO contacts in

3200
M. Moszner et al. / Polyhedron 22 (2003) 3195–3203
Fig. 3. Molecular structure of 2.
Fig. 5. Packing diagram of complex 3 viewed along the c-axis of the
unit cell. Disordered (1:1) molecules of ethanol are represented by the
heavy dashed lines. The remaining dashed lines represent the O–Hꢁ ꢁ ꢁO
hydrogen bonds.
Fig. 4. Molecular structure of 3.
Table 2
ꢁ
Selected distances (A) and angles (°) for 1
Bond distances
Rh(1)–N(2)
Rh(1)–N(3)
Rh(1)–N(1)
Rh(1)–N(4)
Rh(1)–P(1)
Rh(1)–Cl(1)
Zn(1)–O(1)
Zn(1)–O(4)
Zn(1)–O(5)
Zn(1)–Cl(2)
1.994(2)
1.996(2)
2.031(2)
2.035(2)
2.3248(11)
2.4022(12)
1.937(2)
1.946(2)
2.056(2)
2.1847(11)
O(1)–N(1)
O(2)–N(2)
O(3)–N(3)
O(4)–N(4)
O(5)–C(9)
N(1)–C(2)
N(2)–C(3)
N(3)–C(6)
N(4)–C(7)
1.339(3)
1.343(3)
1.339(3)
1.345(3)
1.458(5)
1.301(3)
1.283(4)
1.295(4)
1.295(4)
Bond angles
N(2)–Rh(1)–N(3)
N(2)–Rh(1)–N(1)
N(3)–Rh(1)–N(1)
P(1)–Rh(1)–Cl(1)
96.89(10)
77.73(10)
173.47(9)
179.51(3)
N(2)–Rh(1)–N(4)
N(3)–Rh(1)–N(4)
N(1)–Rh(1)–N(4)
172.60(9)
77.96(10)
107.04(10)

M. Moszner et al. / Polyhedron 22 (2003) 3195–3203
3201
Table 3
ꢁ
Selected distances (A) and angles (°) for 2
Bond distances
Rh1–N1
Rh1–N2
Rh1–P1
2.0196(16)
1.9842(16)
2.4245(5)
1.9930(17)
1.9805(17)
2.3317(5)
1.313(2)
O1–N1
O2–N2
O3–N3
O4–N4
N2–C3
N3–C24
N4–C25
1.304(2)
1.376(2)
1.323(2)
1.370(2)
1.297(2)
1.306(3)
1.293(3)
Rh2–N3
Rh2–N4
Rh2–Cl1
N1–C2
Bond angles
N2i–Rh1–N2
N2i–Rh1–N1i
N2i–Rh1–N1i
P1–Rh1–P1i
180.0
N4–Rh2–N4ii
N4–Rh2–N3
N4ii–Rh2–N3
Cl1ii–Rh2–Cl1
180.0
78.00(6)
102.00(6)
180.0
78.86(7)
101.14(7)
180.0
Symmetry transformations used to generate equivalent atoms: none x; y; z; (i) ꢀx; 1 ꢀ y; 1 ꢀ z; (ii) 2 ꢀ x; ꢀy; ꢀz.
Table 4
ꢁ
Selected distances (A) and angles (°) for 3
Bond distances
Rh(1)–N(2)
Rh(1)–N(4)
Rh(1)–N(3)
Rh(1)–N(1)
Rh(1)–P(1)
Rh(1)–I(1)
O(1)–N(1)
1.973(4)
1.985(4)
1.989(4)
1.996(4)
2.3441(11)
2.6879(5)
1.315(5)
O(2)–N(2)
O(3)–N(3)
O(4)–N(4)
N(1)–C(2)
N(2)–C(3)
N(3)–C(6)
N(4)–C(7)
1.372(5)
1.318(5)
1.377(5)
1.297(6)
1.295(6)
1.310(6)
1.295(6)
Bond angles
N(2)–Rh(1)–N(4)
N(2)–Rh(1)–N(3)
N(4)–Rh(1)–N(3)
N(2)–Rh(1)–N(1)
N(4)–Rh(1)–N(1)
N(3)–Rh(1)–N(1)
N(2)–Rh(1)–P(1)
174.91(15)
100.29(15)
78.81(15)
78.78(15)
101.60(15)
174.23(15)
91.01(11)
N(3)–Rh(1)–P(1)
N(1)–Rh(1)–P(1)
N(2)–Rh(1)–I(1)
N(4)–Rh(1)–I(1)
N(3)–Rh(1)–I(1)
N(1)–Rh(1)–I(1)
P(1)–Rh(1)–I(1)
94.59(11)
91.12(11)
89.08(10)
85.87(10)
86.53(10)
87.76(10)
178.84(3)
Table 5
Selected bond lengths in rhodoximes (A)
ꢁ
Compound
Rh–N (av)
2.014(2)
N–O (av)
1.342(3)
N–C (av)
1.294(4)
Rh–L
Reference
this work
[Rh(Hdmg)(ClZn{C2H5OH}dmg) (PPh3)Cl] (1)
2.4022(12),
2.3248(11),
2.4245(5),
2.3317(5),
2.6879(5),
2.3441(11),
2.322(3)
Rh–Cl,
Rh–P
Rh–P
[Rh(Hdmg)2(PPh3)2]þ
2.0019(16)
1.9865(17)
1.986(4)
1.340(2)
1.3447(2)
1.346(5)
1.305(2)
1.299(3)
1.299(6)
this work
this work
[Rh(Hdmg)2(Cl2)] ꢁ 2CH3OHꢀ (2)
Rh–Cl
Rh–I
Rh–P
[Rh(Hdmg)2(PPh3)I] ꢁ 0.5EtOH (3)
[Rh(Hdmg)((H2dmg)Cl2]
[Rh(Hdmg)2)(NH3)2]þ
[Rh(Hdmg)Cl2]ꢀ
1.997(10)
1.998(5)
1.990(5)
1.992(4)
1.349(13)
1.345(6)
1.350(5)
1.337(6)
1.301(15)
1.302(6)
1.291(7)
1.296(7)
Rh–Cl
Rh–NH3
Rh–Cl
Rh–Cl
Rh–P
[23]
[18]
2.078(6),
2.329(1),
2.381(1),
2.327(1),
2.6423(4)
2.079(3)
[Rh(Hdmg)2(PPh3)Cl]
[7c]
[2a]
[2a]
[Rh(Hdmg)2pyI]
Rh–I
Rh–py
Rh–Cl
[Rh(Hdmg)2 pyCl]
2.3290(4)
ꢀ
ꢁ
ꢁ
the [Rh(Hdmg)(PPh3)Cl] complex [7c]. The distance of
1.9415(2) A, the Cl anion at 2.4022(12) A, and addi-
tionally one ethanol molecule through the O(5) oxygen
ꢁ
3.260(3) A between the zinc-chelating oxygen atoms,
O(1)–O(4), is almost identical to that found for
ꢁ
[Rh(Hdmg)(ClZndmg)(PPh3)]2, 3.25 A [12]. An inter-
ꢁ
at a distance of 2.056(2) A, thus forming a tetrahedral
environment of the Zn2þ cation (Table 2). At the same
esting feature is that the zinc cation of 1 binds two ox-
ygen atoms of the dmg2ꢀ moiety at the mean distance of
time the same ethanol molecule forms the OHꢁ ꢁ ꢁCl–Rh
ꢁ
hydrogen bond with a distance of 3.072(3) A.

3202
M. Moszner et al. / Polyhedron 22 (2003) 3195–3203
(e) D. Steinborn, U. Sedlak, M. Dergatz, J. Organomet. Chem.
415 (1991) 407;
The Oꢁ ꢁ ꢁO contacts between the dimethylglyoxime
ꢁ
rings in 2 are 2.728(2) and 2.695(2) A for the cation and
(f) N. Bresciani Pahor, R. Dreos-Garlatti, S. Geremia, L.
Randaccio, G. Tauzher, E. Zangrado, Inorg. Chem. 29 (1990)
3437;
anion, respectively. The methanol molecule is bonded to
ꢁ
the O(5)–Hꢁ ꢁ ꢁO(3) moiety at a distance of 2.763(2) A.
(g) K.R. Hows, A. Bakac, J.H. Espenson, Inorg. Chem. 27 (1988)
3147;
The distances O(4)ꢁ ꢁ ꢁO(1) and O(2)ꢁ ꢁ ꢁO(3), 2.716(5) and
ꢁ
2.600(5) A, respectively, for 3, are in the range for O
(h) J.H. Espenson, U. Tinner, J. Organomet. Chem. C 43 (1981)
212;
atoms in O–Hꢁ ꢁ ꢁO bridges.
To sum up, the first instance of a bimetallic oximato
compound containing Rh(III) and Zn(II) centres, 1, has
been obtained and structurally determined in addition to
two new rhodoximes, 2 and 3. It has been demonstrated
that rhodium compounds with dioximato ligands can
serve as suitable models for designing heteronuclear
complexes. Our investigations have shown the ability of
the coordination sphere in rhodoximes to undergo many
different rearrangements, which can influence the activ-
ity of the rhodium centre.
(i) C. Bied-Charreton, A. Gaudamer, C.A. Chapmann, D. Dodd,
D. Dass Gupta, M.D. Johnson, B.L. Lockman, B. Septe, J. Chem.
Soc., Dalton Trans. (1978) 1807;
(j) J.H. Weber, G.N. Schrauzer, J. Am. Chem. Soc. 93 (1970) 726.
[3] (a) R. Dreos Garlatti, G. Tauzher, Polyhedron 9 (1990) 2051;
(b) R. Dreos Garlatii, G. Tauzher, M. Blaschini, G. Costa, Inorg.
Chim. Acta 105 (1985) 129;
(c) R. Dreos Garlatii, G. Tauzher, M. Blaschini, G. Costa, Inorg.
Chim. Acta 86 (1984) L63.
[4] (a) E.N. SalÕnikova, M.L. Khidekel, Izv. Akad. Nauk SSSR, Ser.
Khim. (1967) 223;
(b) S.A. Shchepinov, E.N. SalÕnikova, M.L. Khidekel, Izv. Akad.
Nauk SSSR, Ser. Khim. (1967) 2128;
(c) B.G. Rogachev, M.L. Khidekel, Izv. Akad. Nauk SSSR, Ser.
Khim. (1969) 141;
4. Supplementary material
ꢀ
(d) M. Moszner, A.M. Trzeciak, J.J. Ziołkowski, J. Mol. Catal.
A: Chem. 130 (1998) 241.
[5] W.B. Panov, M.L. Khidekel, S.A. Shchepinov, Izv. Akad. Nauk
SSSR, Ser. Khim. (1968) 2397.
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. CCDC –199485, 199486 and
199487 for structures 1, 2 and 3, respectively. Copies of
this information may be obtained free of charge from
The Director, CCDC, 12 Union Road, Cambridge, CB2
1EZ, UK (fax +44-1223-336-033; e-mail: deposit@
ccdc.cam.ac.uk or www: http:== www:ccdc:cam:ac: uk).
[6] C. Tavagnacco, M. Moszner, S. Cozzi, S. Peressini, G. Costa, J.
Electroanal. Chem. 448 (1998) 41.
[7] (a)
M. Moszner, F. Asaro, S. Geremia, G. Pellizer, C.
Tavagnacco, Inorg. Chim. Acta 261 (1997) 161;
(b) F. Asaro, R. Dreos-Garlatti, G. Pellizer, G. Tauzher, Inorg.
Chim. Acta 211 (1993) 27;
(c) F.A. Cotton, J.G. Norman Jr., J. Am. Chem. Soc. 93 (1971)
80;
(d) P. Powell, J. Chem. Soc. A (1969) 2418;
(e) F.P. Dwyer, R.S. Nyholm, Proc. R. Soc. N.S.W. 78 (1944)
266.
Acknowledgements
[8] A. Bakac, J.H. Espenson, Inorg. Chem. 19 (1980) 242.
€
[9] (a) F. Birkelbach, U. Florke, H.J. Haupt, C. Butzlaff, A.X.
Tratwein, K. Wieghardt, P. Chaudhuri, Inorg. Chem. 37 (1998)
2000;
Financial support from the Polish State Committee
for Scientific Research (Grant no. PBZ-KBN 15/09/T09/
99/01d) is gratefully acknowledged.
€
(b) F. Birkelbach, M. Winter, U. Florke, H.J. Haupt, C. Butzlaff,
M. Lengen, E. Bill, A.X. Trutwein, K. Wieghardt, P. Chaudhuri,
Inorg. Chem. 33 (1994) 3990;
(c) F. Lloret, R. Ruiz, B. Cervera, I. Castro, M. Julve, J. Faus,
J.A. Real, F. Spina, Y. Jounaux, J.C. Colin, M. Verdaguer, J.
Chem. Soc. Chem. Commun. (1994) 2615;
References
€
(d) E. Colacio, J.M. Dominguez-Vera, A. Escuer, R. Kivekasand,
[1] (a) S. Hirota, E. Kosugi, L.G. Marzilli, O. Yamauchi, Inor.
Chim. Acta 275–276 (1998) 90;
A. Romerosa, Inorg. Chem. 33 (1994) 3914;
(e) R. Ruiz, F. Lloret, M. Julve, Inorg. Chim. Acta 219 (1994)
178.
(b) L.G. Marzilli, A. Gerli, A.M. Calafat, Inorg. Chem. 31 (1992)
4617;
[10] T. Ramasami, J.H. Espenson, Inorg. Chem. 19 (1980) 1846.
[11] J.H. Espenson, R.C. McHatton, Inorg. Chem. 20 (1981) 3090.
(c) A. Gerli, G. Marzilli, Inorg. Chem. 31 (1992) 1152;
(d) L. Randacio, N. Bresciani-Pahor, E. Zangrado, Chem. Soc.
Rev. 18 (1989) 225;
ꢀ
[12] M. Kubiak, T. Głowiak, M. Moszner, J.J. Ziołkowski, F. Asaro,
G. Costa, G. Pellizer, C. Tavagnacco, Inorg. Chim. Acta 236
(1995) 141.
(e)
N. Bresciani-Pahor, M. Forcolin, L.G. Marzilli, L.
Randaccio, M.F. Summers, P. Toscano, Coord. Chem. Rev.
63 (1985) 1.
[13] P. Braustein, J. Rose, in: G. Wilkinson, F.G.A. Stone, E.W. Abel
(Eds.), Comprehensive Organometallic Chemistry, vol. 10, Perg-
amon, Oxford, UK, 1995.
[2] (a) S. Geremia, R. Dreos, L. Randaccio, G. Thauzer, Inorg.
Chim. Acta. 216 (1994) 125;
[14] P. Starynowicz, COSABS99, program for absorption correction,
University of Wrocław, 1999.
[15] G.M. Sheldrick, SHELXS 97, program for solution of crystal
(b) D. Steinborn, M. Ludwig, J. Organomet. Chem. 463 (1993)
65;
(c) B. Giese, J. Hartung, C. Kesselheim, H.J. Lindner, I. Svoboda,
Chem. Ber. 126 (1993) 1193;
€
structures, University of Gottingen, 1997.
[16] G.M. Sheldrick, HELXL 97, program for crystal structure
refinement, University of Gottingen, 1997.
S
(d) L. Randaccio, S. Geremia, R. Dreos-Garlatti, G. Tauzher, F.
Asara, G. Pellizer, Inorg. Chim. Acta. 194 (1992) 1;
€

M. Moszner et al. / Polyhedron 22 (2003) 3195–3203
3203
[17] (a) W.C. Trogler, R.C. Stewart, L.A. Epps, L.G. Marzilli, Inorg.
Chem. 13 (1974) 1564;
[20] U. Tinner, J.H. Espenson, J. Am. Chem. Soc. 103 (1981)
2120.
€
[21] D. Steinborn, M. Raush, C. Bruhn, H. Schmidt, D. Strohl, J.
Chem. Soc. Dalton Trans. (1998) 221.
(b) G. Costa, G. Tauzher, A. Poxeddu, Inorg. Chim. Acta 3(1969)45.
[18] Yu.A. Simonov, L.A. Nemchinova, A.V. Ablov, V.E. Zavodnik,
O.A. Bologa, Zh. Strukt. Khim. 17 (1976) 142.
[22] R. Dreos, G. Tauzher, S. Geremia, L. Randaccio, F. Asaro, G.
Pellizer, Inorg. Chem. 33 (1994) 5404.
ꢀ ꢀ ꢀ
[23] M. Megnamisi-Belombe, Z. Naturforsch. 44b (1988) 5.
[19] R. Dreos, G. Tauzher, S. Geremia, L. Randaccio, F. Asaro, G.
Pellizer, C. Tavagnacco, G. Costa, Inorg. Chem. 33 (1994) 5404.