Hetero-binuclear complexes containing a Ru0 → Mn+ bond bridged by P,N-phosphine ligands: Convenient synthesis of tridentate organometallic trans-Ru(CO)3(L)2 (L = phosphine bearing an N-donor substituent) ligands

Article abstract of DOI:10.1039/b108287f

A convenient new synthesis of trans-Ru(CO)₃(μ-L)₂ [L = 2-(diphenylphosphino)pyridine, N-(diphenylphosphinomethyl)morpholine)] was developed. The reactions of these two tridentate organometallic ligands with selected group 11 and 12 metal salts resulted in the formation of hetero-binuclear Ru⁰ → Mⁿ⁺ [M = Ag(I), n = 1; Hg(II), Cd(II), n = 2] complexes with Ru-Ag = 2.7132(7) A, Ru-Hg = 2.7075(4) A and Ru-Cd = 2.7750(9) A, as determined by X-ray crystallography.

Full text of DOI:10.1039/b108287f

View Article Online / Journal Homepage / Table of Contents for this issue
Hetero-binuclear complexes containing a Ru0 ! Mn+ bond
bridged by P,N-phosphine ligands: convenient synthesis of
tridentate organometallic trans-Ru(CO)3(L)2 (L = phosphine
bearing an N-donor substituent) ligands
Hai-Bin Song,a Zheng-Zhi Zhangb and Thomas C. W. Mak*a
a
Department of Chemistry, T he Chinese University of Hong Kong, Shatin, New Territories,
Hong Kong SAR, P. R. China. E-mail: tcwmak@cuhk.edu.hk; Fax: +852 2603-5057
State Key Laboratory of Elemento-OrganicChemistry, Nankai Uni versity, Tianjin, P. R. China
b
Received (in New Haven, CT, USA) 11th September 2001, Accepted 5th October 2001
First published as an Advance Article on the web
A convenient new synthesis of trans-Ru(CO)3(m-L)2 [L ¼ 2-(diphenylphosphino)pyridine,
N-(diphenylphosphinomethyl)morpholine)]was developed. The reactions of these two tridentate
organometallic ligands with selected group 11 and 12 metal salts resulted in the formation of hetero-binuclear
+
Ru0 ! Mn+ [M ¼ Ag(I), n ¼ 1; Hg(II), Cd(II), n ¼ 2]complexes with Ru–Ag ¼ 2.7132(7) A, Ru–Hg ¼ 2.7075(4)
+
+
A and Ru–Cd ¼ 2.7750(9) A, as determined by X-ray crystallography.
Binuclear complexes containing a metal–metal bond have
been studied intensively due to their interesting structural
features, spectral properties and wide applications.1 The
formation of a metal–metal bond depends on two factors: (i)
a favorable Lewis acid-base relationship between the two
metals and (ii) suitability of the bridging ligands. Most
binuclear complexes are stabilized through a bridging ligand
with short dentate separation, but unsupported metal–metal
dative bonds can also be formed.2 The hemilabile bridging
ligand 2-(diphenylphosphino)pyridine, Ph2Ppy, has been
widely used to coordinate different metals.3 Due to the
presence of its basic nitrogen site that acts as an effective
‘‘proton messenger’’, the monodentate P-coordination mode
of Ph2Ppy plays a crucial role in the rhodium-catalyzed
hydroformylation of styrene and palladium-catalyzed car-
bonylation of alkynes.3e–g On the other hand, due to elec-
tronic differentiation between the nitrogen and phosphorus
sites, this ligand readily coordinates different metals to form
hetero-binuclear complexes, some of which exhibit interesting
luminescent properties.1b,3 In some catalytic applications, the
synergistic effect confers to the hetero-binuclear com-
plexes higher activities and conversion rates as compared to
the mononuclear complexes.3
cylclohexane-like ring such as piperazine5a or morpholine5b
has a pyramidal configuration that ensures its efficient coor-
dination to a metal atom. Hence we employed the non-rigid
phosphine ligand N-(diphenylphosphinomethyl)morpholine,
Ph2PCH2morph, to prepare the new tridentate organometallic
ligand trans-Ru(CO)3(Ph2PCH2morph)2 , whose reactivity and
formation of hetero-binuclear complexes with mercury(II) and
cadmium(II) salts are also reported.
Experimental
Unless otherwise stated, all reactions were performed under a
nitrogen atmosphere using Schlenk techniques. The solvents
were purified by standard methods. Infrared spectra were
recorded on a Shimadzu 435 spectrometer as KBr discs. The
31P{1H} NMR spectra were recorded on a JEOL EX270
spectrometer at 109.25 MHz using H3PO4 as the external
standard and CDCl3 as solvent. Ru3(CO)12 (Strem) was used
as received, as were AgOTf (Acros), HgI2 (Strem), CdI2
(Strem) and Ph2PH (Aldrich). The ligand 2-(diphenylpho-
sphino)pyridine was prepared by the literature method.3a
Binuclear complexes containing a ruthenium carbonyl group
and a metal–metal dative bond are scarce as there exists no
efficient method of preparing mononuclear P-coordinated
ruthenium(0) carbonyl compounds.4 Here we report a new
procedure to synthesize trans-Ru(CO)3(Ph2Ppy)2 whose hetero-
binuclear complex with silver(I) is also described.
Thus far, most P,N-phosphine ligands used in the synthesis
of metal–metal bonded binuclear complexes have been rigid
pyridylphosphine ligands with a short P,N-donor separation.
The paucity of aminophosphine ligands functioning in the
bidentate bridging mode is due to (i) the nearly planar con-
figuration around the amino nitrogen atom in a primary
amine, secondary amine or aromatic amine and (ii) the low
Lewis basicity of a tertiary amine, which does not favor its
coordination to a metal center. Our previous work has
established that the tertiary amino nitrogen atom in a
Synthetic procedures
N-(Diphenylphosphinomethyl)morpholine. This ligand, abb-
reviated as Ph2PCH2morph, was used in our previous work5b
but the synthetic procedure and 31P{1H}NMR spectra data
were not reported. Ph2PH (9.3 g, 50 mmol), morpholine (4.3
g, 50 mmol) and finely ground paraformaldehyde (1.65 g, 55
mmol) were added to 100 cm3 toluene with stirring; the
mixture was heated to 70–80 ꢀC and stirred at this
temperature for 24 h to form a clear solution. After cooling,
the solution was filtered through a 2 cm celite pad, and the
solvent was removed from the filtrate in vacuo. EtOH (50 ml)
was added to the oily residue and the solution was cooled
to
À20 ꢀC
overnight.
Colorless
micro-crystals
of
Ph2PCH2morph were collected by filtration in 65% yield.
m.p. 53–55 C; 31P{1H}NMR: d ¼ À 27.1.
DOI: 10.1039/b108287f
New J. Chem., 2002, 26, 113–119
113
This journal is # The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2002

View Article Online
trans-[Ru(CO)3(Ph2Ppy)2], 1. 4Ru3(CO)12 (1 mmol) was
added to a Schlenk tube containing 20 cm3 liquid ammonia
at À50 ꢀC. Then cut pieces of sodium metal (6 mmol) were
introduced and the colorless solution immediately turned
solution was concentrated. Et2O diffusion gave colorless
crystals of 6 Á CH2Cl2 (0.08 g, 70%). Method b: compound 2
was dissolved in dichloromethane and the solution was
allowed to stand for 1 week. Methanol was added to deposit
yellow crystals of 6 Á 0.5CH2Cl2 (0.104 g, 95%) at À20 ꢀC.
Anal found: C, 54.05; H, 4.93; N, 3.34; calcd for
C36H40N2O4Cl2P2Ru: C, 54.14; H, 5.05; N, 3.51. IR (nCO):
blue. The solution was stirred continuously for
2 h
at À50 ꢀC, during which time the color changed to pale
yellow; liquid ammonia was then allowed to slowly
evaporate. After the residue was further dried in vacuum to
remove the residual ammonia, a mixture of 20 cm3 EtOH
with 0.15 g (1.5 mmol) concentrated H2SO4 (98%) was
added and the solution stirred for 2 min. The phosphine
ligand Ph2Ppy (6 mmol) was next introduced and the
solution heated to 70 ꢀC for 2 h, during which time a large
amount of yellow precipitate appeared. After the reaction
was complete, the solution was cooled to room temperature
and the precipitate was filtered. The solid was dissolved in
20 cm3 CH2Cl2 , filtered, and concentrated to 5 cm3. Then
15 cm3 CH3OH was added and the solution cooled in a
refrigerator overnight. Pure product 1 appeared as a pale
yellow precipitate and was collected by filtration and
vacuum dried. Yield: 50%. The n(CO) IR and 31P NMR
spectra were identical to those reported in the literature.4 IR
2050s, 1987s cmÀ 1
;
31P{1H} NMR: d ¼ 21.2.
X-Ray crystallography
For complexes 3 and 4 Á Et2O, a selected single crystal was
mounted on a Bruker SMART 1000 CCD diffractometer
operating at 50 kV and 30 mA using Mo-Ka radiation
+
(0.71073 A). Data collection at 293 K and reduction were
performed using SMART and SAINT software,6 with frames
of 0.3ꢀ oscillation in the range 1.5ꢀ < y < 28ꢀ. An empirical
absorption correction was applied using the SADABS pro-
gram.7
The data for 5 Á Et2O was collected at 293 K on a Rigaku
RAXIS IIC imaging plate diffractometer using Mo-Ka
radiation from a rotating anode generator operating at 50 kV
and 90 mA, 36=5ꢀ oscillation frames in the range of 0–180ꢀ,
and exposure of 8 min per frame. A self-consistent semi-
empirical absorption correction based on Fourier coefficient
fitting of symmetry-equivalent reflections was applied using the
ABSCOR program.8
The data for 6 Á CH2Cl2 and 6 Á 0.5CH2Cl2 were collected at
293 K in the variable o-scan mode on a Siemens R3m=V four-
circle diffractometer using Mo-Ka radiation (50 kV, 30 mA;
2ymax ¼ 50ꢀ for 6 Á CH2Cl2 and 52ꢀ for 6 Á 0.5CH2Cl2). An
empirical absorption correction was applied using c-scan data.
All structures were solved by direct methods and all non-
hydrogen atoms were subjected to anisotropic refinement by
full-matrix least-squares on F2 using the SHELXTL package.9
Non-hydrogen atoms were subjected to anisotropic refine-
(nCO): 1897s cmÀ 1
;
31P{1H} NMR: d ¼ 50.1.
trans-[Ru(CO)3(Ph2PCH2morph)2], 2. The above procedure
was repeated using PH2PCH2morph to give 2 in 65% yield.
Anal. found: C, 58.85; H, 5.28; N, 3.60; calcd for
C37H40N2O5P2Ru: C, 58.80; H, 5.33; N, 3.71. IR (nCO):
1973w, 1885s cm-1; 31P{1H} NMR: d ¼ 16.8.
[Ru(m-Ph2Ppy)2(CO)3AgCF3SO3], 3. AgCF3SO3 (0.036 g,
0.14 mmol) was added to a solution of 1 (0.1 g, 0.14 mmol)
in THF (5 cm3). The mixture was stirred for 20 min at room
temperature. The solution was filtered and the filtrate
concentrated. Benzene was diffused into the concentration
solution to give yellow crystals of 3 (0.109 g, 80%). Anal.
found: C, 47.17; H, 3.11; N, 2.93; calcd for
C38H28N2O6F3P2SRuAg: C, 47.12; H, 2.91; N, 2.89. IR
ment. All hydrogen atoms were generated geometrically (C–H
bond lengths fixed at 0.96 A), assigned appropriate isotropic
+
(nCO): 2022s, 1978s, 1951s cmÀ 1
;
31P{1H} NMR: d ¼ 59.4.
thermal parameters, and included in structure factor calcula-
tions in the final stage of F2 refinement. Selected X-ray data
are given in Table 1.
CCDC reference numbers 169883–169887. See http:== www.rsc.
org=suppdata=nj=b1=b108287f= for crystallographic data in
CIF or other electronic format.
[Ru(m-Ph2PCH2morph)2(CO)3HgI2], 4. HgI2 (0.068 g, 0.15
mmol) was added to a solution of 2 (0.1 g, 0.13 mmol) in
dichloromethane (30 cm3). The mixture was stirred for 2 h at
room temperature. The solution was filtered and the filtrate
concentrated. n-Hexane was added to deposit 4 as a yellow
solid (0.13 g, 83%). Anal. found: C, 37.05; H, 3.26; N, 2.25;
calcd for C37H40N2O5P2RuI2Hg: C, 36.72; H, 3.33; N, 2.31.
Results and discussion
IR (nCO): 2060m, 1999s cmÀ 1
;
31P{1H} NMR: d ¼ 34.4,
Overtheyears, thesynthesisoftrans-Ru(CO)3(L)2 (L ¼ phosphine
ligand) has been developed in several ways. For instance:
(i) Ligand-exchange reaction:4b
2J(199Hg, 31P) ¼ 123 Hz. Re-crystallization of 4 in CHCl3–
Et2O yielded yellow crystals of 4 Á Et2O for X-ray analysis.
Ru3ðCOÞ12 þ cod ! RuðCOÞ3ðcodÞ
[Ru(m-Ph2PCH2morph)2(CO)3CdI2], 5. CdI2 (0.055 g, 0.15
mmol) was added to a solution of 2 (0.1 g, 0.13 mmol) in
dichloromethane (15 cm3). The mixture was stirred for 2 h at
room temperature. The solution was filtered and the filtrate
concentrated. Ether was added to deposit yellow crystals of
5 Á Et2O (0.095 g, 65%). Anal. found: C, 40.06; H, 3.35; N,
2.30; calcd for C37H40N2O5P2RuI2Cd: C, 39.61; H, 3.59; N,
80 ꢀC
RuðCOÞ3cod þ PR3 ÀÀ! trans-RuðCOÞ3ðPR3Þ2
(ii) Redox reaction:10a
110À130 ꢀ
C
RuCl3 þ PR3 þ HCOH þ KOHÀÀÀÀÀ! trans-RuðCOÞ3ðPR3Þ2
2.50. IR (nCO): 2034m, 1983s, 1955s cmÀ 1 31P{1H} NMR:
;
(iii) Photochemical reaction:4a
d ¼ 36.9, 2J(111Cd, 31P) ¼ 28 Hz. Re-crystallization of 5 in
CHCl3–Et2O yielded well-formed yellow crystals of 5 Á Et2O
for X-ray analysis.
hn=r:t
Ru3CO12 þ PR3 ÀÀ! trans-RuðCOÞ3ðPR3Þ2
It is not convenient to use Ru(CO)3(cod) in the synthesis
because it slowly decomposes, even when stored at À20 ꢀC.10b,c
The second method is very useful for phosphine ligands that
contain no basic and heat-sensitive functional groups, but it is
not applicable if the ligand contains a N-donor atom, which
would preferentially coordinate to the Ru atom at the expense
trans,cis-Ru(CO)2(m-Ph2PCH2morph)2Cl2 , 6. This com-
pound can be prepared in two ways. Method a: compound 2
(0.1 g, 0.13 mmol) and HgCl2 (0.035 g, 0.13 mmol) were
mixed in dichloromethane (10 cm3) and the solution was
stirred for 2 h. After filtering off the black precipitate, the
114
New J. Chem., 2002, 26, 113–119

View Article Online
Table 1 X-ray crystallographic data refinement parameters of the complexes
3
4 Á Et2O
37H40HgI2N2-
5 Á Et2O
37H40CdI2N2-
6 Á CH2Cl2
C36H40Cl2N2-
6 Á 0.5CH2Cl2
C36H40Cl2N2-
O4P2Ru Á 0.5CH2Cl2
841.07
Formula
C38H28AgF3N2-
O6P2RuS
968.56
C
C
O5P2Ru Á Et2O
O5P2Ru Á Et2O
O4P2Ru Á CH2Cl2
M
Crystal system
1284.23
1196.04
883.54
Triclinic
P1 (no. 2)
11.170(2)
11.430(2)
18.240(3)
75.620(3)
74.322(3)
64.449(3)
1999.5(5)
2
1.060
14 093
9437 (0.0379)
4764
0.0553, 0.1187
0.1287, 0.1501
Monoclinic
P21/c (no. 14)
14.6934(8)
12.7794(7)
24.918(1)
90
91.410(1)
90
4677.4(4)
4
5.033
31 692
11 260 (0.0403 )
7303
0.0311, 0.0602
0.0628, 0.0670
Monoclinic
P21/c (no. 14)
14.682(3)
12.739(3)
24.921(5)
90
91.54(3)
90
4659.4(16)
4
2.218
13 197
7730 (0.0704)
6754
0.0601, 0.1605
0.0702, 0.1688
Triclinic
P1 (no. 2)
11.062(2)
11.362(2)
18.146(4)
95.48(2)
Tetragonal
I41/a (no. 88)
20.928(2)
20.928(2)
17.798(4)
90
90
90
7795(2)
8
0.730
6595
2914 (0.0490)
1910
0.0487, 0.1274
0.0893, 0.1464
Space group
+
a=A
+
b=A
+
c=A
a=ꢀ
b=ꢀ
94.42(2)
g=ꢀ
113.05(1)
2072.8(7)
2
0.752
8671
7300 (0.0538)
4132
0.0670, 0.1238
0.1363, 0.1531
+
U=A3
Z
m(Mo-Ka)=mmÀ 1
Total reflect.
Unique reflect. (Rint
Obsd reflect.
)
R1, wR2 [I > 2s(I)]a
R1, wR2 (all data)
a
2
R1 ¼ S(jFoj À jFcj)=SjFoj; wR2 ¼ {w[S(jFoj À jFcj)2]=SjFoj }1=2
.
of the desired P-coordination. The third method is a photo-
chemical process using ultra-violet radiation, and the optimum
reaction conditions change with different ligands. In cases
where the phosphine ligand bears a photo-sensitive group such
as anthracene, it is not workable. Clearly, there is a need for a
new convenient procedure that makes use of commercially
available chemicals as starting materials.
It is noted that a selective synthesis of the iron analog
trans-Fe(CO)3(PR3)2 was reported in the late 1980’s by Keiter
and Brunet and their coworkers,11 who used Fe(CO)5 to react
with KOH (or NaOH, or NaBH4) and different types of
phosphine ligands PR3 in refluxing n-butanol or ethanol to
obtain the product in high yield. The key intermediate of this
reaction is [HFe(CO)4]À , which suggests to us that an ana-
logous reaction with [HRu(CO)4]À as an intermediate might
be feasible. However, unlike its iron analog Fe(CO)5 ,
Ru(CO)5 is rather unstable and cannot be used as a starting
material. On the other hand, it is known that Ru3(CO)12
reacts with a solution of sodium metal in liquid ammonia to
form Na2[Ru(CO)4].12 Accordingly, we proceeded to carry
out the reaction as represented by the following equation and
obtained trans-Ru(CO)3(L)2 (L ¼ P,N-phosphine ligand) in
good yield:
Scheme 1
CH2Cl2 .14 So we carried out the reaction in THF instead of
CH2Cl2 and obtained the Ru–Ag binuclear complex, although
the Ru–Cu complex proved to be unstable and was not isolated.
According to our previous findings,5b,15 when the organo-
metallic ligand trans-M(CO)3(PR3)2 coordinates with another
metal to form a binuclear complex, (i) the local symmetry of M
changes from D3h to C2v , which causes n(CO) splitting, and (ii)
the formation of a metal–metal dative bond decreases the
electron density at M and consequently the dp(M) ! p*(CO)
p-back bonding, which results in an increase of n(CO) with
respect to the free ligand. As expected, the n(CO) IR spectrum
of binuclear complex 3 shows both characteristics. The 31P
NMR spectrum of complex 3 exhibits a singlet at 59.4 ppm,
indicating that the two phosphine moieties are chemically
equivalent.
The molecular structure of compound 3 is depicted in Fig. 1,
and selected bond lengths and angles are listed in Table 2.
Complex 3 displays a distorted octahedral geometry about the
Ru atom, in which both P–Ru bonds are tilted toward the
silver atom with an unusually small P(1)–Ru(1)–P(2) angle of
155.53(6)ꢀ. This is rather different from what is seen in the
related binuclear complexes Ru(CO)3(m-Ph2Ppy)2MCl2
(M ¼ Zn, Cd, Hg),4b in which the RuP2 unit is much closer to
being linear [P–Ru–P angle: 169.6(1)–173.9(1)ꢀ], and in the
iron analogs Fe(CO)3(m-Ph2Ppy)2MX2 (M ¼ Cu, Ag, Cd, Hg;
X ¼ Cl, Br, I, SCN, ClO4), in which the FeP2 unit is also close
to linear (P–Fe–P angle: 168–174ꢀ). On the other hand, the
three CO ligands and silver atom lie approximately in a plane.
Ru3ðCOÞ12 þ NaðNH3Þ ! Na2½RuðCOÞ4ꢁ
ðiÞ 0:25 equiv: H2SO4
ÀÀÀÀÀÀÀÀÀ! trans-RuðCOÞ3ðLÞ2
ðiiÞ 2 equiv: L
The key intermediate [HRu(CO)4]À is more reactive than
[HFe(CO)4]À , as the reaction time of 2 h for the ruthenium
complex is 12 times less than that required for the iron
complex. It is worthy of note that an attempt to prepare the
osmium analog using Os3(CO)12 by the same procedure was
unsuccessful, though the reason is unclear.
The reaction of ligands 1 and 2 with different metal salts is
shown in Scheme 1. Ligand 1 has been employed to react with
group 12 metal salts in CH2Cl2 to form binuclear compounds
that feature a weak Ru–Zn bond, a strong Ru–Hg bond, and
strong Ru–Cd bonds.4b However, using copper(I) and silver(I)
salts under the same conditions resulted in a redox reaction in
which 1 suffered decomposition and the metal(I) ions were
reduced to metallic powder. This phenomenon is similar to that
observed in the reaction of Fe(CO)3(PR3)2 with silver salts
{which yield metallic silver and the unstable cationic radical
[Fe(CO)3(PR3)2]+}13 and indicates that the [Ru(CO)3-
(Ph2Ppy)2]+ radical is also formed. On the other hand, it has
been reported that silver salts are less exoergic in THF than in
The silver atom is four-coordinated and adopts a distorted
+
tetrahedral geometry with Ag–N ¼ 2.373(5) and 2.404(6) A,
+
+
Ag–O ¼ 2.295(6) A and Ru–Ag ¼ 2.7132(7) A, while the bond
angles vary from 93.2(1) to 144.0(2)ꢀ. The Ru–Ag distance is
smaller than the sum of the metallic radii of Ru and Ag
New J. Chem., 2002, 26, 113–119
115

View Article Online
+
Table 2 Selected bond lengths (A) and angles (ꢀ) for molecules 3–6
3
Ru(1)–C(1)
Ru(1)–C(2)
Ru(1)–C(3)
Ru(1)–P(1)
Ru(1)–P(2)
1.944(8)
1.926(7)
1.918(7)
2.367(2)
2.357(2)
Ag(1)–Ru(1)
Ag(1)–N(1)
Ag(1)–N(2)
Ag(1)–O(4)
2.7132(7)
2.373(5)
2.404(6)
2.295(6)
P(1)–Ru(1)–P(2)
C(1)–Ru(1)–C(2)
C(1)–Ru(1)–C(3)
C(2)–Ru(1)–C(3)
C(1)–Ru(1)–P(1)
C(2)–Ru(1)–P(1)
C(3)–Ru(1)–P(1)
C(1)–Ru(1)–P(2)
C(2)–Ru(1)–P(2)
C(3)–Ru(1)–P(2)
P(1)–Ru(1)–Ag(1)
155.53(6)
100.1(3)
156.5(3)
103.4(3)
89.0(2)
102.0(2)
86.5(2)
88.0(2)
P(2)–Ru(1)–Ag(1)
C(1)–Ru(1)–Ag(1)
C(2)–Ru(1)–Ag(1)
C(3)–Ru(1)–Ag(1)
O(4)–Ag(1)–Ru(1)
N(1)–Ag(1)–Ru(1)
N(2)–Ag(1)–Ru(1)
N(1)–Ag(1)–N(2)
O(4)–Ag(1)–N(1)
O(4)–Ag(1)–N(2)
78.10(4)
72.3(2)
172.4(2)
84.2(2)
144.0(2)
93.9(1)
93.2(1)
110.3(2)
105.4(2)
107.6(2)
102.4(2)
86.6(2)
77.86(4)
4 Á Et2O
Ru(1)–C(1)
Ru(1)–C(2)
Ru(1)–C(3)
Ru(1)–P(1)
1.950(4)
1.938(5)
1.947(5)
2.387(1)
Ru(1)–P(2)
Hg(1)–Ru(1)
Hg(1)–I(1)
Hg(1)–I(2)
2.389(1)
2.7075(4)
2.8128(4)
2.7948(4)
P(1)–Ru(1)–P(2)
C(1)–Ru(1)–P(1)
C(2)–Ru(1)–P(1)
C(3)–Ru(1)–P(1)
C(1)–Ru(1)–P(2)
C(2)–Ru(1)–P(2)
C(3)–Ru(1)–P(2)
C(2)–Ru(1)–C(1)
C(3)–Ru(1)–C(1)
178.83(4)
90.2(1)
89.0(1)
92.0(1)
88.6(1)
91.1(1)
89.1(1)
100.6(2)
158.0(2)
C(2)–Ru(1)–C(3)
P(1)–Ru(1)–Hg(1)
P(2)–Ru(1)–Hg(1)
C(1)–Ru(1)–Hg(1)
C(2)–Ru(1)–Hg(1)
C(3)–Ru(1)–Hg(1)
Ru(1)–Hg(1)–I(2)
Ru(1)–Hg(1)–I(1)
I(2)–Hg(1)–I(1)
101.3(2)
86.55(3)
93.37(3)
81.3(1)
175.1(1)
76.9(1)
127.74(1)
122.57(1)
106.62(1)
5 Á Et2O
Ru(1)–C(1)
Ru(1)–C(2)
Ru(1)–C(3)
Ru(1)–P(1)
Ru(1)–P(2)
1.930(8)
1.937(7)
1.941(7)
2.372(2)
2.379(2)
Ru(1)–Cd(1)
Cd(1)–N(1)
Cd(1)–I(1)
Cd(1)–I(2)
2.7750(9)
2.519(5)
2.7728(8)
2.7857(9)
P(1)–Ru(1)–P(2)
C(1)–Ru(1)–C(2)
C(1)–Ru(1)–C(3)
C(2)–Ru(1)–C(3)
C(1)–Ru(1)–P(1)
C(2)–Ru(1)–P(1)
C(3)–Ru(1)–P(1)
C(1)–Ru(1)–P(2)
C(2)–Ru(1)–P(2)
C(3)–Ru(1)–P(2)
178.64(6)
103.9(3)
154.1(3)
101.9(3)
93.0(2)
89.1(2)
90.1(2)
88.4(2)
90.6(2)
88.7(2)
C(1)–Ru(1)–Cd(1)
C(2)–Ru(1)–Cd(1)
C(3)–Ru(1)–Cd(1)
P(1)–Ru(1)–Cd(1)
P(2)–Ru(1)–Cd(1)
N(1)–Cd(1)–I(1)
N(1)–Cd(1)–Ru(1)
I(1)–Cd(1)–Ru(1)
N(1)–Cd(1)–I(2)
I(1)–Cd(1)–I(2)
74.7(2)
171.9(2)
80.2(2)
83.05(5)
97.28(5)
112.8(1)
93.8(1)
123.18(2)
93.3(1)
107.74(3)
6 Á CH2Cl2
Ru(1)–C(1)
Ru(1)–C(2)
Ru(1)–P(1)
1.854(9)
1.894(8)
2.411(2)
Ru(1)–P(2)
Ru(1)–Cl(1)
Ru(1)–Cl(2)
2.407(2)
2.441(2)
2.447(2)
C(1)–Ru(1)–C(2)
C(1)–Ru(1)–P(1)
C(2)–Ru(1)–P(1)
C(1)–Ru(1)–P(2)
C(2)–Ru(1)–P(2)
P(2)–Ru(1)–P(1)
C(1)–Ru(1)–Cl(1)
C(2)–Ru(1)–Cl(1)
90.6(3)
96.0(2)
92.4(2)
90.1(2)
91.0(2)
173.05(7)
92.9(3)
176.5(2)
P(1)–Ru(1)–Cl(1)
P(2)–Ru(1)–Cl(1)
C(1)–Ru(1)–Cl(2)
C(2)–Ru(1)–Cl(2)
P(1)–Ru(1)–Cl(2)
P(2)–Ru(1)–Cl(2)
Cl(1)–Ru(1)–Cl(2)
87.70(7)
88.59(7)
177.2(3)
86.6(2)
84.49(7)
89.63(6)
89.91(7)
a
6 Á 0.5CH2Cl2
Ru(1)–C(1)
Ru(1)–P(1)
1.880(9)
2.410(1)
Ru(1)–Cl(1)
2.432(2)
C(1)–Ru(1)–C(1)#1
C(1)–Ru(1)–P(1)
C(1)–Ru(1)–P(1)#1
P(1)#1–Ru(1)–P(1)
C(1)–Ru(1)–Cl(1)#1
89.7(5)
94.1(2)
91.3(2)
172.4(1)
90.5(2)
C(1)–Ru(1)–Cl(1)
P(1)–Ru(1)–Cl(1)#1
P(1)–Ru(1)–Cl(1)
Cl(1)#1–Ru(1)–Cl(1)
178.6(2)
87.24(5)
87.34(5)
89.4(1)
a
Symmetry code #1: À x + 1, À y + 3=2, z.
+
+
(2.78 A) and those in ruthenium clusters containing a Ru–Ag
(CF3CO2) Á 0.5CH2Cl2 , and 2.767 and 2.806 A16c in (dppm)-
Ru3(CO)12AgPPh3 . This is suggestive of the presence of a
fairly strong Ru ! Ag donor–acceptor bond in 3.
+
bond: 2.812 and 2.825 A16a in Ru4H2(CO)12Ag(Ph3P)2 Á
+
CH2Cl2 , 2.730 and 2.802 A16b in (dppm)2Ru3(CO)8Ag-
116
New J. Chem., 2002, 26, 113–119

View Article Online
Fig. 1 Perspective view (35% thermal ellipsoids) of the molecular
structure of [Ru(CO)3(m-Ph2Ppy)2AgCF3SO3], 3. In this and all other
figures, the hydrogen atoms have been omitted for clarity.
Fig. 2 Perspective view (35% thermal ellipsoids) of the molecular
structure of [Ru(CO)3(m-Ph2PCH2morph)2HgI2][Ph 2PCH2morph ¼
N-(diphenylphosphinomethyl)morpholine], 4, in 4 Á Et2O.
N-(Diphenylphosphinomethyl)morpholine, Ph2PCH2morph,
is a non-rigid ligand whose phosphorus and nitrogen atoms are
more basic than those in Ph2Ppy. On the other hand, the basicity
of Ru is higher than that of Fe.4b This may be the reason that
Ph2PCH2morph reacts with Na[RuH(CO)4]to give a higher
yield of compound 2 than the reaction of Ph2Ppy. Similar to the
:
and cis-Ru(CO)4[HgRu3(CO)9(m-C C-t-Bu)]2 [2.658(1) and
+
2.655(1) A],17b but shorter than those in [Ru6(m-Hg)4-
+
(m-ampy)2(CO)18][2.839(1), 2.859(1) and 2.841(1)
A,
ampy ¼ 2-amino-6-methyl-pyridine].17c The relatively long
iron analog, compound 2 exhibits a strong n(CO) at 1885 cmÀ 1
,
Hg(1)Á Á ÁN(1) and Hg(1)Á Á ÁN(2) distances of 2.790 and 3.789
indicating that the three CO groups are equivalent; the 31P NMR
signal of 2 is a singlet at 16.8 ppm, indicating that the two
phosphine moieties are chemically equivalent.
+
A imply that only one nitrogen atom has a weak interac-
+
tion with the mercury atom (the distance of 2.790 A is
+
longer than the range of 2.26–2.56 A found for mercury–
Treatment of 2 with HgI2 and CdI2 gave the corresponding
hetero-bimetallic complexes 4 and 5, respectively. The IR
spectra of 4 and 5 also show splitting and a shift to higher
wavenumbers, as expected. The 31P NMR spectra of com-
pounds 4 and 5 each exhibits a singlet with two low-intensity
satellite peaks [2J(199Hg, 31P) ¼ 123 Hz and 2J(111Cd, 31P) ¼ 28
Hz]. The coupling values are comparable with those in com-
plexes containing Ru–Hg and Ru–Cd bonds, for example: 432
Hz17a in cis-Ru(CO)3(m-Ph2Ppy)(HgBr)2 , 109.9 Hz4b in [trans-
Ru(CO)3(m-Ph2Ppy)2HgCl]2(Hg2Cl6) and 23 Hz4b in trans-
Ru(CO)3(m-Ph2Ppy)2Cd(ClO4)2 . Our attempt to prepare a
Ru–Hg complex by treating 2 with HgCl2 was unsuccessful
tertiary amine complexes18).
In complex 5, the Cd atom is four-coordinated with a Ru–
Cd bond distance of 2.7750(9) A, which is comparable to the
+
and compound
6
of formula trans, cis-Ru(CO)2(m-
Ph2PCH2morph)2Cl2 was isolated. Compound 6 was also
obtained from a solution of 6 in dichloromethane or chloro-
form upon prolonged standing. Single crystals of the solvates
6 Á CH2Cl2 and 6 Á 0.5CH2Cl2 were obtained from crystal-
lization of 6 from CH2Cl2–Et2O and CH2Cl2–MeOH, respec-
tively.
ORTEP drawings with atom numbering for molecules 4–6
in 4 Á Et2O, 5 Á Et2O, and 6 Á CH2Cl2 are shown in Figs. 2–4,
respectively. Selected bond lengths and angles are listed in
Table 2. All these complexes display a distorted octahedral
geometry about the Ru atom, in which the RuP2 unit is
nearly linear with a P–Ru–P angle close to 180ꢀ. The three
CO ligands and M in 4 and 5, as well as the two CO moieties
and two Cl atoms in 6, lie in a plane perpendicular to the
RuP2 axis.
Complexes 4 and 5 are isomorphous with their iron(0)
analogs.5b In complex 4, the Hg atom is only three-coor-
dinated with a Ru–Hg distance of 2.7075(4) A, which is
comparable to those of the Ru–Hg dative bond in cis-
+
Fig. 3 Perspective view (35% thermal ellipsoids) of the molecular
structure of [Ru(CO)3(m-Ph2PCH2morph)2CdI2], 5, in 5 Á Et2O.
+
Ru(CO)3(m-Ph2Ppy)(HgBr)2 [2.628(2) and 2.602(2) A]17a
New J. Chem., 2002, 26, 113–119
117

View Article Online
(c) C. Francio, R. Scopelliti, C. G. Arena, G. Bruno,
D. Drommi and F. Faraone, Organometallics, 1998, 17, 338;
(d ) K. B. Shiu, S. S. Young, S. I. Chen, J. Y. Chen, H. J. Wang,
S. L. Wang, S. M. Peng and Y. H. Liu, Organometallics, 1999,
18, 4244; (e) T. Yamaguchi, F. Yamazaki and T. Ito, J. Am.
Chem. Soc., 1999, 121, 7405; ( f ) T. Murahashi, T. Otani,
T. Okuno and H. Kurosawa, Angew. Chem., Int. Ed., 2000, 39,
537; (g) F. A. Cotton, E. V. Dikarev, M. A. Petrukhina and
R. E. Taylor, J. Am. Chem. Soc., 2001, 123, 5831; (h) C. Floriani,
E. Solari, F. Franceschi, R. Scopelliti, P. Belanzoni and M. Rosi,
Chem. Eur. J., 2001, 7, 3052; (i) P. Braunstein, J. Durand,
M. Knorr and C. Strohmann, Chem. Commun., 2001, 211;
( j ) P. Braunstein, M. Veith, J. Blin and V. Huch, Organome-
tallics, 2001, 20, 627; (k) S. M. Reid, J. T. Mague and
M. J. Fink, J. Am. Chem. Soc., 2001, 123, 4081; (l ) A. F. Heyduk
and D. G. Nocera, Science, 2001, 293, 1639.
2
3
For example: (a) R. J. Batchelor, H. B. Davis, F. W. B. Einstein
and R. K. Pomeroy, J. Am. Chem. Soc., 1990, 112, 2036; (b) J. L.
Male, H. B. Davis, R. K. Pomeroy and D. R. Tyler, J. Am. Chem.
Soc., 1994, 116, 9353.
(a) G. R. Newkome and D. C. Hager, J. Org. Chem., 1978, 43, 947;
(b) G. R. Newkome, Chem. Rev., 1993, 93, 2067; (c) Z.-Z. Zhang
and H. Cheng, Coord. Chem. Rev., 1996, 147, 1; (d) P. Espinet and
K. Soulantica, Coord. Chem. Rev., 1999, 195, 499; (e) V. J. Cata-
lano, B. L. Bennett, S. Muratidis and B. C. Noll, J. Am. Chem.
Soc., 2001, 123, 173; ( f ) S. Gladiali, L. Pinna, C. G. Arena,
E. Rotondo and F. Faraone, J. Mol. Catal., 1991, 66, 183;
(g) E. Drent, P. Arnoldy and P. H. M. Budzelaar, J. Organomet.
Chem., 1994, 475, 57; (h) A. Scrivanti and U. Matteoli, T etra-
hedron L ett., 1995, 36, 9015; (i) Z.-Z. Zhang, H.-P. Xi, W.-J. Zhao,
K.-Y. Jiang, R.-J. Wang, H.-G. Wang and Y. Wu, J. Organomet.
Chem., 1993, 454, 221.
Fig. 4 Perspective view (35% thermal ellipsoids) of the molecular
structure of trans,cis-[Ru(CO)2(Ph2PCH2morph)2Cl2], 6, in 6 Á CH2Cl2 .
4
5
For previous syntheses of this compound, see: (a) A. Maisonnet,
J. P. Farr, M. M. Olmstead, C. T. Hunt and A. L. Balch, Inorg.
Chem., 1982, 21, 3961; (b) W.-H. Chan, Z.-Z. Zhang, T. C. W.
Mak and C.-M. Che, J. Chem. Soc., Dalton T rans., 1998, 803.
(a) S.-M. Kuang, Z.-Z. Zhang, Q.-G. Wang and T. C. W. Mak,
Inorg. Chem., 1998, 37, 6090; (b) H.-B. Song, Q.-M. Wang,
Z.-Z. Zhang and T. C. W. Mak, J. Organomet. Chem., 2000,
605, 15.
Bruker SMART 5.0 and SAINT 4.0 for Windows NT, Area
Detector Control and Integration Software, Bruker Analytical
X-Ray Systems, Inc., Madison, WI, USA, 1998.
G. M. Sheldrick, SADABS, Program for Empirical Absorption
Correction of Area Detector Data, University of Gottingen,
¨
+
sum of Ru and Cd metallic radii (2.73 A) and those of the
Ru(0)–Cd(II) dative bond in trans-Ru(CO)3(m-Ph2Ppy)2CdCl2
+
[2.771(1)
A]and
trans-Ru(CO)3(m-Ph2Ppy)2Cd(ClO4)2
+
[2.705(1) A].4b This is suggestive of a strong Ru-Cd bond in
compound 5. The Cd–N distances are 2.519(5) and 4.0 A,
+
6
7
8
9
indicating that only one nitrogen atom is coordinated to the
cadmium atom.
The 1 : 1 and 2 : 1 solvates of compound 6 with CH2Cl2
crystallize in different space groups: triclinic (P1) and tetra-
gonal (I4t=a), respectively. Molecule 6 in 6 Á CH2Cl2 has
pseudo-Cs symmetry in which the two phosphine ligands are
almost mirror images across the plane containing the Ru atom,
two CO groups and two cis chloro ligands. In the crystal
structure of 6 Á 0.5CH2Cl2 , a crystallographic C2 axis bisects
the planar Ru(CO)2Cl2 unit of the molecule.
Germany, 1996.
T. Higashi, ABSCOR, An Empirical Absorption Correction
Based on Fourier Coefficient Fitting, Rugaku Corporation,
Tokyo, Japan, 1995.
G. M. Sheldrick, SHELXTL 5.10 for Windows NT, Structure
Determination Software Programs, Bruker Analytical X-Ray
Systems, Inc., Madison, WI, USA, 1997.
10 (a) N. Ahmad, J. J. Levison, S. D. Robinson and M. F. Uttley,
Inorg. Synth., 1974, 15, 45; (b) A. J. P. Domigos, J. A. S. Howell,
B. F. G. Johson and J. Lewis, Inorg. Synth., 1976, 16, 103;
(c) A. J. P. Domigos, J. A. S. Howell, B. F. G. Johson and
J. Lewis, Inorg. Synth., 1990, 28, 52.
Conclusion
We have successfully developed a convenient new procedure
for the preparation of trans-Ru(CO)3(L)2 (L ¼ phosphine
bearing a N-donor substituent) and used the tridentate orga-
nometallic ligands 1 [L ¼ 2-(diphenylphoshino)pyridine]and 2
[L ¼ N-(diphenylphosphinomethyl)morpholine]to react with
the Lewis acids AgCF3SO3 , HgI2 and CdI2 to form hetero-
binuclear complexes containing a Ru0 ! Mn+ [M ¼ Ag(I),
Hg(II), Cd(II)]dative bond.
11 (a) R. L. Keiter, E. A. Keiter, K. H. Hecker and C. A. Boecker,
Organometallics, 1988, 7, 2466; (b) R. L. Keiter, E. A. Keiter,
C. A. Boecker, D. R. Micher and D. R. Hecker, Inorg. Synth.,
1997, 31, 210; (c) J. J. Brunet, F. B. Kindela, D. Labroue
and D. Neibecher, J. Organomet. Chem., 1989, 368, 209;
(d) J. J. Brunet, G. Commenges, F. B. Kindela and D. Neibecker,
Organometallics, 1992, 11, 1343; (e) J. J. Brunet, F. B. Kindela
and D. Neibecker, Inorg. Synth., 1992, 29, 151; ( f ) J. J. Brunet,
R. Chauvin, O. Diallo, F. Kindela, P. Leglaye and D. Neibecker,
Coord. Chem. Rev., 1998, 180, 331.
12 (a) J. D. Cotlon, M. I. Bruce and F. G. A. Stone, J. Chem. Soc. A,
1968, 2162; (b) J. P. Collman, D. W. Murphy, E. B. Fleischer and
D. Swift, Inorg. Chem., 1974, 13, 1.
Acknowledgement
13 J. H. MacNeil, A. C. Chiverton, S. Fortier, M. C. Baird,
R. C. Hynes, A. J. Williams, K. F. Preston and T. Ziegler, J. Am.
Chem. Soc., 1991, 113, 9384.
This work was supported by Hong Kong Research
Grants Council Earmarked Grant ref. no. CUHK 4022/98P.
14 L. Song and W. C. Trogler, Angew. Chem., Int. Ed. Engl., 1992, 31,
770.
15 (a) S.-M. Kuang, H. Cheng, L.-J. Sun, Z.-Z. Zhang, Z.-Y. Zhou,
B.-M. Wu and T. C. W. Mak, Polyhedron, 1996, 15, 3417;
(b) S.-L. Li, T. C. W. Mak and Z.-Z. Zhang, J. Chem. Soc., Dalton
T rans., 1996, 3475; (d) S.-M. Kuang, Z.-Z. Zhang, B.-M. Wu,
T. C. W. Mak and Z.-Z. Zhang, J. Organomet. Chem., 1997, 540,
55; (e) H.-B. Song, Z.-Z. Zhang and T. C. W. Mak, Inorg.
References
1
See, for example: (a) J. P. Farr, M. M. Olmstead and
A. L. Balch, J. Am. Chem. Soc., 1980, 102, 6654; (b) A. L. Balch,
Prog. Inorg. Chem., 1993, 41, 239 and references therein;
118
New J. Chem., 2002, 26, 113–119

View Article Online
Chem., 2001, 40, 5928; ( f ) D.-J. Cui, Q.-S. Li, F.-B. Xu, X.-B.
Leng and Z.-Z. Zhang, Organometallics, 2001, 20, 4126.
16 (a) M. J. Freeman, M. Green, A. G. Orpen, I. D. Salter and
F. G. A. Stone, J. Chem. Soc., Chem. Commun., 1983, 1332;
(b) J. A. Ladd, H. Hope and A. L. Balch, Organometallics, 1984,
3, 1838; (c) M. I. Bruce, M. L. Williams, J. M. Patrick, B. W.
Skelton and A. H. White, J. Chem. Soc., Dalton T rans., 1986,
2557.
25, 194; (c) P. L. Andreu, J. A. Cabeza, A. Llamazares and V. Riera,
J. Organomet. Chem., 1991, 420, 431.
18 See, for example: (a) C. M. Hughes, M. C. Favas, B. W. Skelton
and A. H. White, Aust. J. Chem., 1985, 38, 1521; (b) C. A. Ghilardi,
S. Midollini, A. Orlandini and A. Vacca, J. Organomet. Chem.,
1994, 471, 29; (c) D. C. Bebout, D. E. Ehmann, J. C. Trinidad
and K. K. Crahan, Inorg. Chem., 1997, 36, 4257; (d) F. Cecconi,
C. A. Ghilardi, S. Midollini and A. Orlandin, Inorg. Chim. Acta,
1998, 269, 274; (e) A. Albinati, V. Gramlich, G. Anderegg and F.
Lianza, Inorg. Chim. Acta, 1998, 274, 219; ( f ) D. C. Bebout, J. F.
Bush II and K. C. Crahan, Inorg. Chem., 1998, 37, 4641.
17 (a) S.-M. Kuang, F. Xue, Z.-Y. Zhang, T. C. W. Mak and
Z.-Z. Zhang, J. Organomet. Chem., 1998, 559, 31; (b) E. Rosenberg,
D. Ryckman, I.-N. Hsu and R. W. Gellert, Inorg. Chem., 1986,
New J. Chem., 2002, 26, 113–119
119