Specific synthesis and reaction of hetero- and homobridged diruthenium carbonyl complexes containing one or two μ-azolato bridges

Article abstract of DOI:10.1021/om9600708

Diruthenium(I) carbonyl complexes with either hetero- or homobridges, [Ru₂(μ-Pz)₂(CO)₄-(HPz)₂] (1), [Ru₂(μ-Pz′)(μ-O₂CMe)(CO) ₄(HPz′)₂] (2), and [Ru₂(μ-Pz′)₂(CO)4(HPz′)₂] (3), can be prepared specifically. These complexes reacted with either nucleophiles or electrophiles to produce selectively only one product. The terminal azole groups, pyrazole (HPz) or 3,5-dimethylpyrazole (HPz′), of 1-3 are easily replaced by the phosphine ligands to give [Ru₂-(μ-Pz)₂(CO)₄(PPh₃) ₂] (4), [Ru₂(μ-Pz′)(μ-O₂CMe)(CO)₄(PPh ₃)₂] (5), [Ru₂(μ-Pz′)₂(CO)₄(PPh ₃)₂] (6), and [Ru₂(μ-Pz)₂(CO)₄(η ¹-dppm)₂] (7). The μ-acetato bridge is more fragile than the μ-azolato bridge, and only the former bridge of 5 can be replaced by Pz^- and SR^- to afford [Ru₂(μ-Pz′)(μ-Pz)(CO)₄(PPh₃) ₂] (8) and [Ru₂(μ-Pz′)(μ-SR)(CO)₄(PPh₃) ₂] (R = Ph (9), ^tBu (10)). Heating the mixture of 3 with dppm in THF gave a product retaining all the μ-azolato bridges but losing two carbonyls, [Ru₂(M-Pz′)₂(CO)₂(μ ₁,η²-dppm)₂] (11), whereas a similar reaction between 1-3 and nitrogen-bidentate ligands gave products retaining all four carbonyls but only one μ-azolato bridge, [Ru₂(μ-L)(μ-CO)₂(CO)₂(μ ₁,η²-(N-N))₂]⁺ (L = Pz, N-N = bpy ([12]⁺), phen ([13]⁺); L = Pz′, N-N = bpy ([14]⁺), phen ([15]⁺)). The electrophilic addition of 4 with I₂ produced [Ru₂(μ-Pz)₂(μ-I)(CO)₄(PPh ₃)₂][I₃] (16). The X-ray structure of this product confirms the cleavage of the Ru-Ru bond rather than the μ-azolato bridges. However, the μ-azolato and -acetato bridges, as well as the terminal azole groups, of 1-6 can be easily removed by an electrophilc reagent such as Et₃O⁺BF₄^- in the presence of MeCN to give [Ru₂(CO)₄-(MeCN)₆][BF₄]₂ and [Ru₂(CO)₄(MeCN)₄(PPh₃) ₂][BF₄]₂.

Full text of DOI:10.1021/om9600708

Organometallics 1996, 15, 2979-2987
2979
Sp ecific Syn th esis a n d Rea ction of Heter o- a n d
Hom obr id ged Dir u th en iu m Ca r bon yl Com p lexes
Con ta in in g On e or Tw o µ-Azola to Br id ges
Kom-Bei Shiu,* Wei-Ming Lee, and Chen-Lan Wang
Department of Chemistry, National Cheng Kung University,
Tainan, Taiwan 701, Republic of China
Sue-Lein Wang and Fen-Ling Liao
Department of Chemistry, National Tsing Hua University,
Hsinchu, Taiwan 300, Republic of China
J u-Chun Wang and Lin-Shu Liou
Department of Chemistry, Soochow University,
Taipei, Taiwan 111, Republic of China
Shie-Ming Peng and Gene-Hsiang Lee
Department of Chemistry, National Taiwan University,
Taipei, Taiwan 106, Republic of China
Michael Y. Chiang
Department of Chemistry, National Sun Yat-Sen University,
Kaohsiung, Taiwan 804, Republic of China
Received February 5, 1996X
Diruthenium(I) carbonyl complexes with either hetero- or homobridges, [Ru2(µ-Pz)2(CO)4-
(HPz)2] (1), [Ru2(µ-Pz′)(µ-O2CMe)(CO)4(HPz′)2] (2), and [Ru2(µ-Pz′)2(CO)4(HPz′)2] (3), can be
prepared specifically. These complexes reacted with either nucleophiles or electrophiles to
produce selectively only one product. The terminal azole groups, pyrazole (HPz) or 3,5-
dimethylpyrazole (HPz′), of 1-3 are easily replaced by the phosphine ligands to give [Ru2-
(µ-Pz)2(CO)4(PPh3)2] (4), [Ru2(µ-Pz′)(µ-O2CMe)(CO)4(PPh3)2] (5), [Ru2(µ-Pz′)2(CO)4(PPh3)2] (6),
and [Ru2(µ-Pz)2(CO)4(η1-dppm)2] (7). The µ-acetato bridge is more fragile than the µ-azolato
bridge, and only the former bridge of 5 can be replaced by Pz- and SR- to afford [Ru2(µ-
Pz′)(µ-Pz)(CO)4(PPh3)2] (8) and [Ru2(µ-Pz′)(µ-SR)(CO)4(PPh3)2] (R ) Ph (9), tBu (10)). Heating
the mixture of 3 with dppm in THF gave a product retaining all the µ-azolato bridges but
losing two carbonyls, [Ru2(µ-Pz′)2(CO)2(µ1,η2-dppm)2] (11), whereas a similar reaction between
1-3 and nitrogen-bidentate ligands gave products retaining all four carbonyls but only one
µ-azolato bridge, [Ru2(µ-L)(µ-CO)2(CO)2(µ1,η2-(N-N))2]+ (L ) Pz, N-N ) bpy ([12]+), phen
([13]+); L ) Pz′, N-N ) bpy ([14]+), phen ([15]+)). The electrophilic addition of 4 with I2
produced [Ru2(µ-Pz)2(µ-I)(CO)4(PPh3)2][I3] (16). The X-ray structure of this product confirms
the cleavage of the Ru-Ru bond rather than the µ-azolato bridges. However, the µ-azolato
and -acetato bridges, as well as the terminal azole groups, of 1-6 can be easily removed by
an electrophilc reagent such as Et3O+BF4 in the presence of MeCN to give [Ru2(CO)4-
-
(MeCN)6][BF4]2 and [Ru2(CO)4(MeCN)4(PPh3)2][BF4]2.
In tr od u ction
in being either involved as the active intermediates in
homogeneously catalyzed reactions or catalytic precur-
sors for the carbonylation of amines, the hydrogenation
of carboxylic acids, and the addition of acetic acid to
alkynes,3 we decided to explore the synthesis and
reactivity some diruthenium(I) carbonyl complexes con-
taining the µ-azolato linkage.
The coordination chemistry of the dirhodium and
-iridium complexes has been well studied recently.
Particularly, those containing the µ-azolato bridging
group are under intensive investigations, due to the
ability of the apparently strong µ-azolato bridge en-
abling to straddle an unusual range of intermetallic
separations to hold two adjacent metal centers in
chemically extremely stable configurations.1 In view of
the rarely studied coordination chemistry of the diru-
thenium complexes with the µ-azolato bridge,2 and the
significance of the diruthenium(I) carbonyl complexes
In this paper, we present the following new informa-
tion: (1) a convenient approach to prepare specifically
both hetero- and homobridged diruthenium carbonyl
complexes with one or two µ-azolato linkages, (2) the
selective nucleophilic and electrophilic reactions of these
complexes to give only one type of product, (3) the X-ray
X Abstract published in Advance ACS Abstracts, May 15, 1996.
S0276-7333(96)00070-2 CCC: $12.00 © 1996 American Chemical Society
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2980 Organometallics, Vol. 15, No. 13, 1996
Shiu et al.
structures of eight representative reaction products, and
(4) the novel propensity of the µ-azolato linkage, espe-
cially the cleavable feature first found in the dimetal
system.
Resu lts a n d Discu ssion
Syn th esis. Although complexes [Ru2(µ-L)2(CO)6] (HL
) pyrazole (HPz), 3,5-dimethylpyrazole (HPz′)) were
previously described to be important precursors to
several other ruthenium derivatives, the synthetic ap-
proaches used suffer either a low yield2a,e or a tedious
procedure.2c As demonstrated below, new dinuclear
species in the types of [Ru2(µ-L)2(CO)4(HL)2] and [Ru2(µ-
Pz′)(µ-O2CMe)(CO)4(HPz′)2] can be obtained specifically
in satisfactory yield and employed as better precursors
to a variety of other Ru(I) and Ru(II) derivatives.
Importantly, all the conversions appear to follow selec-
tive pathways.
F igu r e 1. ORTEP plot of 2 with 50% thermal ellipsoids.
Sch em e 1
In the presence of Et3N, catena-[Ru(O2CMe)(CO)2]
reacted with excess HPz or HPz′ in EtOH gave only one
diruthenium derivative with either homo- or hetero-
bridges, [Ru2(µ-Pz)2(CO)4(HPz)2] (1) and [Ru2(µ-Pz′)(µ-
O2CMe)(CO)4(HPz′)2] (2), respectively. The homo-
bridged compounds 1 can be obtained alternatively from
the reaction of [Ru2(CO)4(MeCN)6][BF4]2 with HPz/Et3N
and H2O. Complex [Ru2(µ-Pz′)2(CO)4(HPz′)2] (3) can be
obtained likewise. The reactions involve obviously first
the substitution of MeCN in [Ru2(CO)4(MeCN)6][BF4]2
with a better σ-donor, L-, via HL/Et3N to give [Ru2(µ,η2-
L)2(CO)4(η1-L)]2- and then protonation with H2O to give
1 and 3 (Scheme 1). The specific formation of 2 rather
than a mixture of 2 and 3 reflects probably that the
nucleophilic substitution is stepwise and the steric
hindrance of µ-Pz′ in 2 may inhibit a subsequent
replacement of the remaining µ-acetato group by a
second Pz′-.
Compound 2 was structurally characterized (Figure
1). The heterobridged feature and the two HPz′ groups
ligated to Ru at the axial sites were confirmed. The
Ru-Ru distance of 2.682(1) Å in 2 (Table 1) is signifi-
cantly shorter than that of 2.705(2) Å in [Ru2(η2-Pz′)2-
(CO)6].2a,e The longer distance may be due to a combi-
nation of both electronic and steric factors. The higher
trans influence of the axial carbonyls in this compound,
compared with that of the axial HPz′ groups in 2, and
the larger nonbonded interactions between two bulky
µ-Pz′ groups and other groups in [Ru2(η2-Pz′)2(CO)6],
compared with those between one such µ-Pz′ group and
other groups in 2, may contribute to the Ru-Ru elonga-
tion.
Reaction s with Nu cleoph iles. The two axial groups
in either [Ru2(η2-L)2(CO)6]2e or [Ru2(CO)4(MeCN)6]2+ 4a
were previously reported to be substitution labile.
Complexes 1-3 behave similarly. The two axial HL
groups of 1-3 are easily replaced by phosphine groups
to give [Ru2(µ-Pz)2(CO)4(PPh3)2] (4), [Ru2(µ-Pz′)(µ-O2-
CMe)(CO)4(PPh3)2] (5), [Ru2(µ-Pz′)2(CO)4(PPh3)2] (6),
and [Ru2(µ-Pz)2(CO)4(η1-dppm)2] (7) (Scheme 2) with 5
structurally characterized to confirm the heterobridged
feature (Figure 2). The Ru-Ru distance increases from
2.682(1) Å in 2 to 2.7261(9) Å in 5, apparently due to
the increased nonbonded interactions between the
bulkier PPh3 groups and other groups in the molecule.
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Diruthenium Carbonyl Complexes
Organometallics, Vol. 15, No. 13, 1996 2981
F igu r e 2. ORTEP plot of 5 with 50% probability ellipsoids.
Sch em e 2
Sch em e 3
F igu r e 3. (a) Top: ORTEP plot of 10 with 50% thermal
ellipsoids. (b) Bottom: ORTEP plot of 10 along the Ru-
Ru axis with phenyl and tert-butyl groups omitted.
The 31P{1H} NMR spectrum of 7, like that of [Ru2(µ-
O2CMe)2(CO)4(η1-dppm)2],5 appears as two sets of mul-
tiplets at δ 12.12 and -26.18 ppm consistent with an
AA′XX′ spin system. The structure of 7 is hence believed
to be similar to that of 5.
in a 31P{1H} NMR spectrum.2d However, such a sug-
gestion was questioned, on the basis of our findings that
the µ-Pz′ linkage is rather strong and resistant even
with respect to a strong nucleophile such as a thiolate
anion and that the axial groups in [Ru2(η2-L)2(CO)6],
[Ru2(CO)4(MeCN)6]2+, or 1-3 are substitution labile. In
order to obtain a clear-cut conclusion, we attempted a
similar substitution reaction by following their reaction
condition, i.e., by heating a mixture of 3 and excess
dppm in THF for more than 24 h. The compound we
The µ-acetato bridge, rather than the µ-Pz′ bridge, in
5 can be replaced further by any smaller or stronger
anionic σ-donor, like Pz- or thiolate anion, to give [Ru2-
(µ-Pz′)(µ-Pz)(CO)4(PPh3)2] (8) and [Ru2(µ-Pz′)(µ-SR)-
t
(CO)4(PPh3)2] (R ) Ph (9), Bu (10)) (Scheme 3), respec-
tively. The 31P{1H} NMR spectrum of 10 appears as
two doublets indicating probably the asymmetric ori-
entation of either two PPh3 groups and/or the thiolate
bridge with respect to the Ru-Ru bond. 10 may be rigid
in solution at room temperature on the NMR time scale.
The single-crystal structure of 10 was thus carried out
(Figure 3a). It reveals two asymmetrical PPh3 groups
(Figure 3b) with the P(2) group at the axial site and
the P(1) group at the equatorial site, probably alleviat-
ing the repulsive nonbonded interactions if both groups
are at the axial sites. The Ru-Ru distance is
2.7469(5) Å.
1
obtained shows very similar IR and H-NMR spectral
data to those reported by Su¨ss-Fink’s group. It also
exhibits two multiplets consistent with an AA′XX′ spin
system at δ 11.41 and -30.26, but these two values
differ about 3.6-4.0 ppm from those reported. Further,
the elemental analysis results clearly indicate that the
compound should not be formulated as [Ru2(Pz′)2(CO)4-
(dppm)2] but [Ru2(Pz′)2(CO)2(dppm)2] (11) with only two,
rather than four, carbonyls suggested. The crystal
structure of 11 was hence determined to support this
formulation. As shown in the simplified ORTEP plot
of 11 (Figure 4), each Ru atom of 11 has one chelate
dppm and one CO. The two carbonyls, C(1)O(1) and
C(2)O(2), are in a gauche conformation with the torsion
angle C(1)-Ru(1)-Ru(2)-C(2) ) 85.9°. Obviously the
bidentate ligand dppm can replace only the axial HPz′
and carbonyl groups rather than cleave one or two
apparently strong µ-Pz′ linkages in 3 (Scheme 4).
The reaction product between [Ru2(µ-Pz′)2(CO)6] and
excess dppm was previously reported by Su¨ss-Fink’s
group to be [Ru2(µ-Pz′)2(CO)4(η1-dppm)2], a formula
similar to 7, but an unusal structure was suggested to
have two η1-dppm and one CO groups at one Ru atom
and three CO groups at the other metal atom, probably
on the basis of a typical AA′XX′ spin system observed
(5) Sherlock, S. J .; Cowie, M.; Singleton, E.; Steyn, M. M. d. V.
Organometallics 1988, 7, 1663.
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2982 Organometallics, Vol. 15, No. 13, 1996
Shiu et al.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles (d eg)
Bond Lengths for 2
Ru(1)-Ru(2)
Ru(1)-N(3)
Ru(1)-C(4)
Ru(2)-N(4)
Ru(2)-C(6)
2.682(1)
2.111(7)
1.82(1)
2.103(7)
1.839(10)
Ru(2)-O(6)
C(5)-O(2)
C(7)-O(4)
C(20)-O(6)
N(3)-N(4)
2.170(5)
Ru(1)-N(2)
Ru(1)-C(5)
Ru(1)-O(5)
Ru(2)-N(5)
Ru(2)-C(7)
2.261(7)
1.846(10)
2.170(6)
2.213(7)
1.850(10)
C(4)-O(1)
C(6)-O(3)
C(20)-O(5)
N(1)-N(2)
N(5)-N(6)
1.17(1)
1.135(10)
1.155(10)
1.252(10)
1.376(8)
1.160(10)
1.278(10)
1.362(9)
1.341(9)
Bond Angles for 2
Ru(2)-Ru(1)-N(2)
Ru(2)-Ru(1)-O(5)
O(5)-C(20)-O(6)
C(5)-Ru(1)-C(4)
162.2(2)
84.3(2)
123.6(8)
92.1(3)
O(6)-Ru(2)-C(7)
C(6)-Ru(2)-N(4)
Ru(1)-C(5)-O(2)
Ru(2)-C(7)-O(4)
178.1(3)
169.5(3)
179.0(8)
178.9(9)
Ru(1)-Ru(2)-N(5)
Ru(1)-Ru(2)-O(6)
O(5)-Ru(1)-C(5)
C(4)-Ru(1)-N(3)
160.0(2)
83.7(1)
178.6(3)
167.9(3)
C(7)-Ru(2)-C(6)
Ru(1)-C(4)-O(1)
Ru(2)-C(6)-O(3)
88.1(4)
176.5(9)
178.3(9)
Bond Lengths for 5
Ru(1)-Ru(2)
Ru(1)-N(1)
Ru(1)-C(2)
Ru(2)-P(2)
Ru(2)-C(3)
2.7261(9)
2.129(6)
1.871(8)
2.4324(21)
1.828(8)
Ru(2)-O(6)
C(5)-O(6)
C(2)-O(2)
C(4)-O(4)
Ru(1)-P(1)
2.136(5)
1.246(8)
1.134(9)
1.140(9)
2.4357(21)
Ru(1)-C(1)
1.834(9)
2.142(5)
2.127(6)
1.865(7)
C(5)-O(5)
C(1)-O(1)
C(3)-O(3)
N(1)-N(2)
1.265(9)
1.142(11)
1.147(10)
1.379(8)
Ru(1)-O(5)
Ru(2)-N(2)
Ru(2)-C(4)
Bond Angles for 5
Ru(2)-Ru(1)-P(1)
Ru(1)-Ru(2)-O(6)
O(5)-C(5)-O(6)
C(1)-Ru(1)-C(2)
166.35(7)
83.66(13)
125.1(7)
89.8(4)
O(6)-Ru(2)-C(3)
C(4)-Ru(2)-N(2)
Ru(1)-C(2)-O(2)
Ru(2)-C(4)-O(4)
174.8(3)
164.8(3)
179.2(8)
177.7(8)
Ru(1)-Ru(2)-P(2)
167.04(6)
82.94(13)
176.0(3)
166.4(3)
C(3)-Ru(2)-C(4)
Ru(1)-C(1)-O(1)
Ru(2)-C(3)-O(3)
92.4(3)
178.8(7)
175.8(7)
Ru(2)-Ru(1)-O(5)
O(5)-Ru(1)-C(1)
C(2)-Ru(1)-N(1)
Bond Lengths for 10
Ru(1)-Ru(2)
Ru(1)-S
Ru(1)-C(1)
Ru(2)-P(2)
2.7469(5)
2.3795(10)
1.906(4)
Ru(2)-N(2)
Ru(2)-C(4)
C(1)-O(1)
C(3)-O(3)
2.153(3)
1.859(4)
1.136(6)
1.146(5)
Ru(1)-P(1)
2.3735(10)
2.095(3)
1.865(4)
Ru(2)-C(3)
N(1)-N(2)
C(2)-O(2)
C(4)-O(4)
1.871(4)
1.375(4)
1.144(5)
1.139(5)
Ru(1)-N(1)
Ru(1)-C(2)
Ru(2)-S
2.4261(10)
2.4276(10)
Bond Angles for 10
92.43(12) Ru(1)-Ru(2)-P(2) 157.30(3)
Ru(2)-Ru(1)-P(1) 103.54(3)
Ru(1)-S-Ru(2) 69.69(3)
Ru(1)-Ru(2)-C(4)
N(2)-Ru(2)-C(4)
Ru(1)-C(2)-O(2)
Ru(2)-C(4)-O(4)
C(3)-Ru(2)-C(4)
87.34
162.97(4)
176.0(4)
175.5(4)
C(1)-Ru(1)-C(2)
88.32(18) Ru(1)-C(1)-O(1) 171.2(4)
Ru(2)-Ru(1)-C(1) 154.94(12)
Ru(2)-Ru(1)-C(2) 102.05(12) Ru(2)-C(3)-O(3) 179.2(4)
Ru(1)-Ru(2)-C(3) 102.52(12)
C(2)-Ru(1)-N(1)
172.98(15)
Bond Lengths for 11
Ru(1)-Ru(2)
Ru(1)-P(4)
Ru(1)-N(3)
Ru(2)-P(1)
2.738(1)
2.309(1)
2.112(3)
2.386(1)
Ru(2)-N(2)
Ru(2)-C(2)
C(2)-O(2)
N(3)-N(4)
2.120(3)
1.828(4)
1.168(5)
1.371(4)
Ru(1)-P(3)
2.416(1)
2.136(3)
1.846(4)
2.316(1)
Ru(2)-N(4)
C(1)-O(1)
N(1)-N(2)
2.169(3)
1.150(5)
1.368(4)
Ru(1)-N(1)
Ru(1)-C(1)
Ru(2)-P(2)
Bond Angles for 11
Ru(2)-Ru(1)-P(3)
P(4)-Ru(1)-N(3)
C(1)-Ru(1)-N(3)
175.6(1)
176.1(1)
95.6(1)
P(1)-Ru(2)-P(2)
C(2)-Ru(2)-N(4)
Ru(1)-C(1)-O(1)
72.0(1)
164.5(2)
176.7(3)
P(3)-Ru(1)-P(4)
C(1)-Ru(1)-N(1)
Ru(1)-Ru(2)-P(1)
72.3(1)
157.5(1)
172.3(1)
P(2)-Ru(2)-N(2)
C(2)-Ru(2)-N(2)
Ru(2)-C(2)-O(2)
177.5(1)
88.7(1)
178.4(3)
Bond Lengths for 12
Ru(1)-Ru(2)
Ru(1)-C(24)
Ru(1)-N(1)
Ru(1)-N(5)
Ru(2)-C(27)
2.701(1)
2.009(6)
2.196(5)
2.097(5)
1.866(8)
Ru(2)-C(25)
Ru(2)-N(3)
C(26)-O(3)
C(25)-O(2)
Ru(1)-C(26)
2.009(6)
2.192(4)
1.136(9)
1.178(9)
1.868(7)
Ru(1)-C(25)
2.016(9)
2.194(7)
1.365(8)
2.033(8)
Ru(2)-N(6)
Ru(2)-N(4)
C(27)-O(4)
C(24)-O(1)
2.093(5)
2.192(6)
1.133(10)
1.184(8)
Ru(1)-N(2)
N(5)-N(6)
Ru(2)-C(24)
Bond Angles for 12
Ru(1)-C(24)-Ru(2)
C(24)-Ru(1)-C(25)
C(24)-Ru(1)-N(1)
C(25)-Ru(1)-N(2)
83.9(3)
93.4(3)
169.4(3)
168.9(2)
N(1)-Ru(1)-N(2)
N(5)-Ru(1)-C(26)
Ru(1)-C(26)-O(3)
Ru(1)-C(25)-Ru(2)
74.2(2)
174.5(3)
177.4(8)
84.3(3)
C(24)-Ru(2)-C(25)
C(24)-Ru(2)-N(4)
C(25)-Ru(2)-N(3)
92.9(3)
170.4(2)
167.9(3)
N(3)-Ru(2)-N(4)
N(6)-Ru(2)-C(27)
Ru(2)-C(27)-O(4)
74.0(2)
174.6(3)
177.6(8)
Bond Lengths for 14A
Ru(1)-Ru(2)
Ru(1)-C(5)
Ru(1)-N(1)
Ru(1)-N(3)
Ru(2)-C(2)
2.6953(5)
2.024(4)
2.185(4)
2.124(4)
1.862(5)
Ru(2)-C(6)
Ru(2)-N(5)
C(1)-O(1)
C(5)-O(5)
Ru(1)-C(1)
2.016(4)
2.209(4)
1.136(6)
1.177(5)
1.880(5)
Ru(1)-C(6)
2.008(5)
2.197(4)
1.383(5)
2.017(4)
Ru(2)-N(4)
Ru(2)-N(6)
C(2)-O(2)
C(6)-O(6)
2.132(4)
2.196(4)
1.149(6)
1.182(5)
Ru(1)-N(2)
N(3)-N(4)
Ru(2)-C(5)
Bond Angles for 14A
Ru(1)-C(5)-Ru(2)
C(5)-Ru(1)-C(6)
C(5)-Ru(1)-N(2)
C(6)-Ru(1)-N(1)
83.7(2)
94.6(2)
170.6(2)
167.6(2)
N(1)-Ru(1)-N(2)
N(3)-Ru(1)-C(1)
Ru(1)-C(1)-O(1)
Ru(1)-C(6)-Ru(2)
74.23(14)
172.5(2)
176.8(4)
84.1(2)
C(5)-Ru(2)-C(6)
C(5)-Ru(2)-N(5)
C(6)-Ru(2)-N(6)
94.6(2)
169.3(2)
168.6(2)
N(5)-Ru(2)-N(6)
N(4)-Ru(2)-C(2)
Ru(2)-C(2)-O(2)
73.71(14)
171.5(2)
176.0(4)
Bond Lengths for 15
Ru(1)-Ru(2)
Ru(1)-N(2)
Ru(1)-C(1)
Ru(1)-C(4)
C(3)-O(3)
2.685(1)
2.191(4)
1.873(6)
2.013(6)
1.188(8)
Ru(2)-N(3)
Ru(2)-N(5)
Ru(2)-C(3)
C(2)-O(2)
2.198(4)
2.141(5)
1.997(6)
1.144(9)
2.200(4)
Ru(1)-N(6)
2.103(4)
2.026(6)
1.134(8)
1.175(8)
Ru(2)-N(4)
Ru(2)-C(2)
Ru(2)-C(4)
N(5)-N(6)
2.185(4)
1.851(7)
2.025(6)
1.393(6)
Ru(1)-C(3)
C(1)-O(1)
C(4)-O(4)
Ru(1)-N(1)
+
+

Diruthenium Carbonyl Complexes
Organometallics, Vol. 15, No. 13, 1996 2983
Ta ble 1 (Con tin u ed )
Bond Angles for 15
Ru(1)-C(3)-Ru(2)
C(3)-Ru(1)-C(4)
C(3)-Ru(1)-N(2)
C(4)-Ru(1)-N(1)
83.7(2)
94.7(2)
168.8(2)
171.1(2)
N(1)-Ru(1)-N(2)
N(6)-Ru(1)-C(1)
Ru(1)-C(1)-O(1)
Ru(1)-C(4)-Ru(2)
75.6(2)
172.7(2)
176.8(6)
83.4(2)
C(3)-Ru(2)-C(4)
C(3)-Ru(2)-N(4)
C(4)-Ru(2)-N(3)
95.2(2)
169.4(2)
168.1(2)
N(3)-Ru(2)-N(4)
N(5)-Ru(2)-C(2)
Ru(2)-C(2)-O(2)
75.0(2)
173.6(2)
178.5(6)
Bond Lengths for 16
Ru(1)-I(1)
Ru(2)-I(1)
Ru(1)-P(1)
Ru(1)-N(3)
Ru(1)-C(8)
2.731(2)
Ru(2)-N(2)
Ru(2)-C(9)
C(7)-O(1)
C(9)-O(3)
N(1)-N(2)
2.113(11)
I(2)-I(3)
2.926(2)
Ru(2)-N(4)
Ru(2)-C(10)
C(8)-O(2)
C(10)-O(4)
N(3)-N(4)
2.147(13)
1.903(20)
1.153(25)
1.124(24)
1.347(16)
2.733(1)
2.386(4)
2.105(10)
1.869(20)
1.868(16)
1.131(19)
1.140(21)
1.360(16)
I(3)-I(4)
2.902(2)
2.123(13)
1.877(15)
2.398(4)
Ru(1)-N(1)
Ru(1)-C(7)
Ru(2)-P(2)
Bond Angles for 16
Ru(1)-I(1)-Ru(2)
I(1)-Ru(2)-P(2)
N(1)-Ru(1)-N(3)
87.1(1)
178.9(1)
88.2(4)
C(7)-Ru(1)-C(8)
Ru(1)-C(7)-O(1)
Ru(2)-C(9)-O(3)
90.8(7)
175.8(14)
174.1(11)
I(1)-Ru(1)-P(1)
177.5(1)
173.9(1)
88.7(5)
C(9)-Ru(2)-C(10)
Ru(1)-C(8)-O(2)
Ru(2)-C(10)-O(4)
89.6(8)
173.9(14)
174.0(17)
I(2)-I(3)-I(4)
N(2)-Ru(2)-N(4)
F igu r e 6. ORTEP plot of [14A]+ with 50% probability
ellipsoids.
F igu r e 4. ORTEP plot of 11 with 50% probability el-
lipsoids. Only the ipso-carbon atoms of the phenyl groups
of dppm are shown for clarity.
Sch em e 4
F igu r e 7. ORTEP plot of [15]+ with 50% probability
ellipsoids.
Sch em e 5
F igu r e 5. ORTEP plot of [12]+ with 30% thermal el-
lipsoids.
L)(µ-CO)2(CO)2(µ1,η2-(N-N))2]+ (L ) Pz, N-N ) bpy
([12]+), phen ([13]+); L ) Pz′, N-N ) bpy ([14]+), phen
([15]+)) (Scheme 5). The crystal structures of 12, 14,
and 15 were carried out to confirm the formulation, and
it was found that in each asymmetric unit of the crystal
used were two similar diruthenium molecules, 14A and
14B, found for 14, although only one dimer was ob-
served for 12 and 15. The structures of [12]+, [14A]+,
and [15]+ are shown in Figures 5-7, respectively.
Apparently the more severe steric effect required by bpy
Consistent with the structure of 10 (Figure 3b), phos-
phine groups can occupy the equatorial sites if neces-
sary.
However, excepting the replacement of the axial HL
groups, the less-flexible bidentate ligands such as bpy
and phen can cleave one µ-O2CMe or µ-L bridge, but
without losing any carbonyl in 1-3, to afford [Ru2(µ-
+
+

2984 Organometallics, Vol. 15, No. 13, 1996
Shiu et al.
Sch em e 6
served in the dirhodium and -iridium systems1 but not
yet reported in the diruthenium system.2 From the
crystal structures of 2, 5, 10-12, and 14-16, it is
apparent that the µ-azolato linkage is flexible to main-
tain two metal fragments in close proximity, both within
and beyond the requirements of metal-metal interac-
tions in the dimetal system.
F igu r e 8. ORTEP plot of [16]+ with 50% probability
ellipsoids.
and phen, relative to dppm,5,6 results in a geometry in
12-15 totally different from that in 11.
From the aforementioned results, one or two µ-azolato
linkages in 1-3 appear to be able to survive during a
nucleophilic or electrophilic reaction (Schemes 1-5).
However, some other reactions are present enabling
removal of all the µ-acetato and -azolato linkages in the
compounds.
The µ-O2CMe linkage was previously reported to be
cleavable, and the product [Ru2(µ-O2CMe)(µ-CO)2(CO)2-
(µ1,η2-(N-N))2]+ can be obtained from the reaction of
catena-[Ru(O2CMe)(CO)2] with bpy or phen in EtOH.7
Here we wish to add that the apparently strong µ-L
linkage, previously reported to be a stable bridge in all
dirhodium and -iridium complexes,1 can be cleaved. The
reaction between the heterobridged dimer 2 and N-N
did not give a mixture of [Ru2(µ-O2CMe)(µ-CO)2(CO)2-
(µ1,η2-(N-N))2]+ and [Ru2(µ-L)(µ-CO)2(CO)2(µ1,η2-(N-
N))2]+ but only the latter one, consistent with the
weaker µ-acetato linkage compared with the µ-Pz′
linkage, and the cleaving process is also selective when
bpy or phen is used.
The comparable Ru-Ru distances of 2.701(1) Å in
[12]+, 2.6953(5) Å in [14A]+, 2.6988(5) Å in [14B]+,
2.685(1) Å in [15]+, 2.701(1) Å in [Ru2(µ-O2CMe)(µ-CO)2-
(CO)2(µ1,η2-bpy)2]+,7a and 2.709(1) Å in [Ru2(µ-O2CMe)-
(µ-CO)2(CO)2(µ1,η2-phen)2]+ 7b can be attributed to the
similar flexibility of two bidentate ligands bpy and phen
with the averaged torsion angles N-C-C-N, such as
N(3)-C(15)-C(16)-N(4) in 12, less than 6.4°. The
identical distance of 2.701(1) Å found in both cations
12+ and [Ru2(µ-O2CMe)(µ-CO)2(CO)2(µ1,η2-bpy)2]+ prob-
ably indicates a µ-O2CMe linkage in a steric bulk similar
to a µ-Pz linkage and further supports the facile
replacement of two µ-O2CMe linkages in 1 by µ-Pz
groups to give 4 (Scheme 1).
Rea ction s w ith Electr op h iles. Electrophiles such
as I2 can react with 4. However, it was strange to find
that the reaction should consume up to 2 equiv of I2 to
complete the reaction for every dinuclear compound 4.
Later, the crystal structure of the product compound
was revealed to have an I3- as a counterion for [Ru2(µ-
Pz)2(µ-I)(CO)4(PPh3)2]+ ([16]+; cf., Figure 8 and Scheme
6). Though with two µ-Pz linkages, the two Ru atoms
are separated by 3.762(2) Å, indicating no metal-metal
bonding interactions. Obviously, the electrophilic re-
agent I2 can cleave the Ru-Ru bond and raise the
oxidation state of each Ru atom, but cannot break the
µ-azolato linkage. Such a feature was previously ob-
-
An electrophilic reagent such as Et3O+BF4 in the
presence of MeCN was previously reported by our
laboratory to convert a series of [Ru2(CO)4(µ-O2CMe)2-
(L′)2] (L′ ) MeCN or phosphine (PR3)) into [Ru2(CO)4-
(MeCN)6][BF4]2 and [Ru2(CO)4(MeCN)4(PR3)2][BF4]2,
probably involving an abstraction reaction by transfor-
mation of a µ-acetato bridge into the weakly coordinat-
ing ethyl acetate.4b We found that a similar reaction
also occurs for 1-3 and 4-6 into [Ru2(CO)4(MeCN)6]-
[BF4]2 and [Ru2(CO)4(MeCN)4(PPh3)2][BF4]2, respec-
tively. The former product, [Ru2(CO)4(MeCN)6][BF4]2,
can be converted by adding PPh3 into the latter one,
[Ru2(CO)4(MeCN)4(PPh3)2][BF4]2 (Scheme 6).4a
Con clu sion
Our investigation into the diruthenium carbonyl
complexes containing the µ-azolato linkage resulted in
the specific synthesis of 1-3 in satisfactory yield. Both
nucleophilic and electrophilic reactions of 1-3 produce
selectively one type of product containing either hetero-
or homobridges (Schemes 1-6) as confirmed in eight
X-ray crystal structures (Figures 1-8). The µ-azolato
linkage has been demonstrated to promote formation
of novel compounds such as 11 and to maintain two
ruthenium fragments in close proximity, both within
and beyond the requirements of metal-metal inter-
actions. More importantly, if necessary, the µ-azolato
linkages can be cleaved partially by using the less-
flexible bidentate nucleophiles such as bpy or phen or
removed totally by using electrophiles such as trialkyl-
oxonium reagents. The latter reaction can produce
potentially versatile compounds such as [Ru2(CO)4-
(MeCN)6][BF4]2 and [Ru2(CO)4(MeCN)4(PPh3)2][BF4]2.4
Exp er im en ta l Section
Gen er a l Com m en ts. All solvents were dried and purified
by standard methods [ethers, paraffins, and arenes from
potassium with benzophenone as indicator; halocarbons and
acetonitrile from CaH2; alcohols from the corresponding alkox-
ide] and were freshly distilled under nitrogen immediately
before use. All reactions and manipulations were carried out
in standard Schlenk ware, connected to a switchable double
(6) (a) Puddephatt, R. J . Chem. Soc. Rev. 1983, 12, 99. (b) Balch, A.
L. Homogeneous Catalysis with Metal Phosphine Complexes; Pignolet,
L. H., Ed.; Plenum: New York, 1983; pp 167-213. (c) Chaudret, B.;
Delavaux, B.; Poilblanc, R. Coord. Chem. Rev. 1988, 86, 191.
(7) (a) Steyn, M. M. d. V.; Singleton, E. Acta Crystallogr. 1988, C44,
1722. (b) Frediani, P.; Bianchi, M.; Salvini, A.; Guarducci, R.; Carluccio,
L. C.; Piacenti, F.; Ianelli, S.; Nardelli, M. J . Organomet. Chem. 1993,
463, 187.
+
+

Diruthenium Carbonyl Complexes
Organometallics, Vol. 15, No. 13, 1996 2985
manifold providing vacuum and nitrogen. Reagents and
phosphines were used as supplied by either Aldrich or Strem.
1H and 31P NMR spectra were measured on a Bruker AM-200
(1H, 200 MHz), Bruker AMC-400, or Varian Unity Plus-400
(1H, 400 MHz; 31P, 162 MHz) NMR spectrometer. 1H chemical
shifts (δ in ppm, J in Hz) are defined as positive downfield
relative to internal MeSi4 (TMS) or the deuterated solvent,
while 31P chemical shifts are defined as positive downfield
relative to external 85% H3PO4. The IR spectra were recorded
on a Hitachi Model 270-30 or Bio-Rad FTS 175 instrument.
The following abbreviations were used: s, strong; m, medium;
w, weak; s, singlet; d, doublet; t, triplet; dd, doublet of doublet;
br, broad unresolved signal. Microanalyses were carried out
by the staff of the Microanalytical Service of the Department
of Chemistry, National Cheng Kung University.
(PPh3)2] by comparison of both the NMR and IR spectral
evidences with those reported.2c
Rea ction betw een 2 a n d P P h 3. The yellow compound 5
was prepared from 2 in a procedure similar to that used for 4.
The yield is 97%. Anal. Calcd for C47H40N2O6P2Ru2: C, 56.85;
H, 4.06; N, 2.82. Found: C, 56.78; H, 4.04; N, 2.72. 1H NMR
(25 °C, 200 MHz, CDCl3): PPh3 at 7.60 (br, 12 H), 7.40 (m, 18
H); H4 on µ-Pz′ at 5.67 (s, 1 H); Me3 or Me5 on µ-Pz′ at 1.57
(br, 6 H); µ-O2CMe at 1.75 (s, 3 H). 31P{1H} NMR (25 °C, 162
MHz, CDCl3): 12.50 (s, 2 P). IR (CH2Cl2): vCO, 2028 s, 1982
m, 1954 s cm-1
.
Rea ction betw een 3 a n d P P h 3. The yellow compound 6
was prepared from 3 in a procedure similar to that used for 4.
The yield is 94%. Anal. Calcd for C50H44N4O4P2Ru2: C, 58.36;
H, 4.31; N, 5.44. Found: C, 58.29; H, 4.28; N, 5.57. 1H NMR
(25 , 200 MHz, CDCl3): PPh3 at 7.54-7.23 (m, 30 H); H4 on
µ-Pz′ at 5.63 (s, 1 H), 5.58 (s, 1 H); Me3 or Me5 on µ-Pz′ at 2.27
(s, 3 H), 1.80 (s, 3 H), 1.51 (s, 3 H), 1.46 (s, 3 H). 31P{1H}
NMR (25 °C, 162 MHz, CDCl3): 12.69 (s, 2 P). IR (CH2Cl2):
Syn th esis of [Ru 2(CO)4(µ-P z)2(HP z)2] (1). In a 100-mL
Schlenk flask was added catena-[Ru(O2CMe)(CO)2] (1.0 g, 2.33
mmol), HPz (0.83 g, 12.2 mmol), 5 mL of Et3N, and 30 mL of
EtOH at room temperature. The mixture was then heated
under reflux for 2 h and cooled to room temperature. The
solvent and Et3N were removed under vacuum and the
resulting solid residue was redissolved in 5 mL of MeOH. Upon
addition of 50 mL of H2O, a milky yellow precipitate formed
immediately, which was collected on a medium frit. Recrys-
tallization from CH2Cl2/MeOH afforded the pure product in
91% yield. Alternatively, as described below for 3, 1 can also
be prepared from [Ru2(CO)4(MeCN)6][BF4]2 and HPz/Et3N.
Anal. Calcd for C16H14N8O4Ru2: C, 32.88; H, 2.41; N, 19.17.
Found: C, 32.54; H, 2.39; N, 18.85. 1H NMR (25 °C, 400 MHz,
acetone-d6): NH at 12.87 (br, 2 H); H3 or H5 on HPz at 8.10
(m, 2 H), 7.83 (m, 2 H); H3 and H5 on µ-Pz at 7.09 (m, 4 H); H4
on HPz at 6.64 (m, 2 H,); H4 on µ-Pz at 6.02 (m, 2 H). IR:
v
CO, 2016 s, 1990 m, 1944 s, 1924 m cm-1
Rea ction betw een 1 a n d d p p m . The yellow compound
.
7 was prepared from 1 using dppm in a procedure similar to
that used for 4. The yield is 93%. Anal. Calcd for C60H50
N4O4P4Ru2: C, 59.22; H, 4.14; N, 4.60. Found: C, 59.28; H,
4.08; N, 4.59. 1H NMR (25 °C, 200 MHz, CDCl3): PPh3 at
7.65-7.10 (m, 40 H); H3 and H5 on µ-Pz at 6.46 (d, 4 H, J )
2.2); H4 on µ-Pz at 5.63 (t, 2 H); CH2 of dppm at 3.47 (m, 4 H).
31P{1H} NMR (25 °C, 162 MHz, CDCl3): 12.12 (m, 2 P), -26.18
(m, 2 P). IR (CH2Cl2): vCO, 2024 s, 1982 m, 1954 s cm-1
.
Rea ction betw een 5 a n d Na P z, Na SP h , a n d Na StBu .
A typical reaction is shown as follows. In a 100-mL Schlenk
flask was added 5 (108 mg, 0.109 mmol), NaPz (0.30 g, 3.33
mmol), and 20 mL of THF at room temperature. The mixture
was then heated under reflux for 4 h and cooled to room
temperature. The solvent was removed under vacuum. Re-
crystallization from CH2Cl2/hexane afforded the pure product
(8) in 85% yield. Anal. Calcd for C48H40N4O4P2Ru2: C, 57.59;
H, 4.02; N, 5.59. Found: C, 57.65; H, 3.91; N, 5.54. 1H NMR
(25 °C, 200 MHz, CDCl3): PPh3 at 7.57 (br, 12 H), 7.39 (br, 18
H); H3 and H5 on µ-Pz at 6.89 (d, 2 H, J ) 2.0); H4 on µ-Pz at
5.78 (t, 1 H); H4 on µ-Pz′ at 5.61 (s, 1 H); Me3 and Me5 on µ-Pz′
at 1.56 (s, 6 H). 31P{1H} NMR (25 °C, 162 MHz, CDCl3): 12.12
v
CO, 2024 s, 1976 m, 1942 s cm-1 in CH2Cl2; vNH, 3436 w; vCO
2016 s, 1964 m, 1934 s cm-1 in KBr.
,
Syn th esis of [Ru 2(CO)4(µ-P z′)(µ-O2CMe)(HP z′)2] (2).
The yellow compound 2 was prepared from catena-[Ru(O2-
CMe)(CO)2] using HPz′ in a procedure similar to that used for
1. The yield is 87%. Anal. Calcd for C21H16N6O6Ru2: C, 38.18;
H, 3.97; N, 12.72. Found: C, 38.51; H, 3.99; N, 12.39. 1H NMR
(25 °C, 200 MHz, CDCl3): NH at 10.92 (br, 2 H); H4 on HPz′
at 6.02 (s, 1 H), 6.01 (s, 1 H); H4 on µ-Pz′ at 5.57 (s, 1 H); Me3
or Me5 on HPz′ at 2.48 (br, 6 H), 2.29 (br, 6 H); Me3 or Me5 on
(s, 2 P). IR (CH2Cl2): vCO, 2028 s, 1986 m, 1958 s cm-1
.
µ-Pz′ at 1.38 (br, 6 H); µ-O2CMe at 2.15 (s, 3 H). IR: vCO
,
Compound 9 was prepared from 5 using NaSPh in a procedure
similar to that used for 8. The yield is 87%. Anal. Calcd for
2024 s, 1974 m, 1940 s cm-1 in CH2Cl2; vNH, 3328 w, vCO, 2024
s, 1970 m, 1942 s cm-1 in KBr.
C
51H42N2O4P2Ru2S: C, 58.72; H, 4.05; N, 2.69. Found: C,
Syn th esis of [Ru 2(CO)4(µ-P z′)2(HP z′)2] (3). To the solu-
tion of [Ru2(CO)4(MeCN)6][BF4]2, prepared in situ by the
reaction of [Ru2(CO)4(µ-O2CMe)2(MeCN)2] (0.28 mmol) with
excess Et3O+BF4-,4 in a 100-mL Schlenk flask was added HPz′
(0.14 g, 1.4 mmol), 1 mL of Et3N, and 20 mL of MeOH at room
temperature. The mixture was then heated under reflux for
2 h and cooled to room temperature. The volume of the
solution was reduced to ca. 5 mL under vacuum. Upon
addition of 40 mL of H2O, a milky yellow precipitate formed
immediately, which was collected on a medium frit. Recrys-
tallization from CH2Cl2/MeOH afforded the pure product in
83% yield. Anal. Calcd for C24H30N8O4Ru2: C, 41.38; H, 4.34;
N, 16.08. Found: C, 41.35; H, 4.28; N, 15.83. 1H NMR (25
°C, 200 MHz, CDCl3): NH at 9.80 (br, 2 H); H4 on HPz′ at
6.05 (s, 1 H), 5.81 (s, 1 H); H4 on µ-Pz′ at 5.31 (s, 1 H); Me3 or
Me5 on HPz′ at 2.55 (br, 6 H), 2.24 (br, 6 H); Me3 or Me5 on
µ-Pz′ at 1.55 (br, 12 H). IR: vCO, 2016 s, 1968 m, 1934 s cm-1
in CH2Cl2; vNH, 3424 w, vCO, 2012 s, 1960 m, 1928 s cm-1 in
KBr.
58.76; H, 3.94; N, 2.78. 1H NMR (25 °C, 200 MHz, CDCl3):
PPh3 at 7.38 (br, 12 H), 7.27 (m, 18 H); SPh at 6.81 (m, 5 H);
H4 on µ-Pz′ at 5.42 (s, 1 H); Me3 and Me5 on µ-Pz′ at 1.26 (s,
6 H). 31P{1H} NMR (25 °C, 162 MHz, CDCl3): 24.66 (s, 2 P).
IR (CH2Cl2) vCO, 2016 s, 1982 m, 1946 s cm-1. Compound 10
was prepared from 5 using NaStBu in a procedure similar to
that used for 8. The yield is 90%. Anal. Calcd for C49H44
-
N2O4P2Ru2S: C, 57.53; H, 4.53; N, 2.74. Found: C, 57.33; H,
4.34; N, 2.69. 1H NMR (25 °C, 200 MHz, CDCl3): PPh3 at
7.55-7.26 (m, 30 H); H4 on µ-Pz′ at 5.23 (s, 1 H); Me3 and Me5
on µ-Pz′ at 1.54 (br, 6 H); StBu at 1.12 (s, 9 H). 31P{1H} NMR
(25 °C, 162 MHz, CDCl3): 22.46 (d, 1 P, J ) 8.7), 41.9 (d, 1 P).
IR (CH2Cl2): vCO, 2004 s, 1980 vs, 1934 s cm-1
.
Rea ction betw een 3 a n d d p p m . In a 100-mL Schlenk
flask was added 3 (133 mg, 0.191 mmol), dppm (168 mg, 0.438
mmol), and 30 mL of THF at room temperature. The mixture
was first stirred at this temperature for 10 min and then
heated under reflux for 28 h, giving a clear orange-red solution.
The solvent was removed under vacuum and the resulting solid
redissolved in 40 mL of CH2Cl2. After filtration through a
medium frit, the volume of the filtrate was reduced to ca. 15
mL. A 45 mL volume of hexane was carefully added on the
top of the solution and the two-layer mixture was cooled to
-40 °C for 1 week, giving orange-red crystals. The crystals
were collected on a medium frit and dried in vacuo to give 157
mg of [Ru2(µ-Pz′)2(CO)2(µ1,η2-dppm)2] (11), containing a solvate
Rea ction betw een 1 a n d P P h 3. In a 100-mL Schlenk
flask was added 1 (0.100 g, 0.17 mmol), PPh3 (0.18 g, 0.69
mmol), and 25 mL of MeCN at room temperature. The
solution gradually formed pale yellow precipitate. After 0.5
h, the yellow solid was collected on a medium frit, washed
three times with 5 mL of MeCN, and dried in vacuo to give
0.096 g (80%). This solid was identified as [Ru2(CO)4(µ-Pz)2-
+
+

2986 Organometallics, Vol. 15, No. 13, 1996
Shiu et al.
Ta ble 2. Cr ysta l Da ta
5
compd
2
10
11
formula
fw
C21H26N6O6Ru2
660.61
C47H40N2O6P2Ru2
992.92
C49H46N2O4P4Ru2S
1023.05
C63H60Cl2N4O2P4Ru2
1302.1
color, habit
diffractometer used
space group
a, Å
b, Å
yellow, prism
Rigaku AFC6S
monoclinic,P 21/c
14.069(5)
13.288(3)
14.545(3)
98.25(2)
2691(1)
orange, prism
Nonius CAD4
monoclinic,P21/c
10.4555(16)
16.113(3)
26.063(4)
91.420(13)
4389.6(13)
4
orange, prism
Nonium CAD4
monoclinic, P21/n
13.0086(18)
17.363(3)
20.945(3)
104.251(12)
4585.3(12)
4
orange, equant
Siemens SMART-CCD
monoclinic, P21/n
13.970(3)
25.737(5)
16.826(3)
92.65(3)
6043(2)
4
1.431
c, Å
â, deg
V, Å3
Z
4
D
calcd, g cm-3
1.630
1.502
1.482
λ(Mo KR), Å
F(000)
0.710 69
1320
0.710 69
1998
0.710 69
2070
0.710 73
2656
unit cell detn: no. 2θ range, deg
20, 8-12
25, 17-23
25, 17-26
whole data
hemisphere
1-52
scan type
ω-2θ
θ-2θ
θ-2θ
2θ range, deg
6-50
16,15,(17
11.67
2-50
(12,19,30
7.89
2-50
(15,20,24
7.57
h,k,l range
(17,31,20
7.40
µ(Mo KR), cm-1
cryst size, mm
temp, K
0.41 × 0.41 × 0.66
0.20 × 0.20 × 0.30
0.30 × 0.35 × 0.35
0.4 × 0.4 × 0.4
296
298
298
297
no. of measd reflns
no. of unique reflns
no. of obsd reflns (No)
5228
5014
3407 (>3σ)
0.047, 0.048
4.00
4227
4227
2345 (>2σ)
0.044, 0.041
1.08
8063
8063
5956 (>2σ)
0.031, 0.031
1.28
27 384
10 543
7883 (>3σ)
0.038, 0.038
1.70
R,a Rw
a
GOFa
refinement program
no. of ref params (Np)
weighting scheme
g (2nd ext coeff) × 10e4
TEXSAN
316
NRCVAX
532
NRCVAX
SHELXTL-PLUS
695
542
[σ2(Fo)]-1
0
[σ2(Fo) + 0.0002Fo
]
[σ2(Fo) + 0.0001Fo
0.95(4)
]
[σ2(Fo) + 0.0001Fo
0.000052(8)
0.42
]
2
-1
2
-1
2 -1
0
(
(
F)max, e Å-3
F)min, eÅ-3
0.79
-1.28
0.40
-0.41
0.44
-0.36
-0.44
compd
12
14
15
16
formula
fw
C52H41BCl2N6O4Ru2
1097.8
C59H48Cl2F12N12O8P2Ru4 C34H25Cl2F6N2O4PRu2 C47.5H36Cl3I4N4O4P2Ru2
1818.21 999.6 1604.8
color, habit
diffractometer used
orange, rhombohedron orange, equant
Siemens SMART-CCD Siemens SMART-CCD
yellow-brown, lamellar orange-brown, irregular
Siemens SMART-CCD Siemens P4
space group
a, Å
b, Å
triclinic, P1h
10.712(4)
13.939(4)
17.871(7)
67.156(14)
84.40(2)
85.273(16)
2444.5(17)
2
triclinic, P1h
14.4764(2)
15.0429(2)
17.0034(1)
97.829(1)
106.942(1)
103.125(1)
3367.16(7)
2
orthorhombic, Pbca
17.614(2)
13.624(2)
31.294(2)
90
triclinic, P1h
11.744(1)
13.357(1)
20.173(2)
93.19(1)
95.09(1)
112.90(1)
2889.3(4)
2
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
90
90
7509.6(15)
8
1.768
D
calcd, g cm-3
1.491
1.793
1.845
λ(Mo KR), Å
F(000)
0.710 73
1108
0.710 73
1796
0.710 73
3952
0.710 73
1524
unit cell detn: no. 2θ range, deg whole data
whole data
hemisphere
3-51
whole data
hemisphere
3-53
25, 24 < 2θ < 25
scan type
hemisphere
3-47
(11,(15,19
7.78
θ-ω
2θ range, deg
4-45
12,(14,(21
28.96
h,k,l range
(17,(17,20
11.02
20,16,36
10.66
µ(Mo KR), cm-1
cryst size, mm
temp, K
0.3 × 0.3 × 0.4
0.48 × 0.45 × 0.38
0.61 × 0.46 × 0.08
0.15 × 0.3 × 0.4
298
296
296
298
no. of measd reflns
no. of unique reflns
no. of obsd reflns (No)
9549
6877
5837 (>4σ)
0.055, 0.068
1.89
19 376
11 036
11033 (>2σ)
0.040, 0.051
1.09
32 873
6756
4934 (>3σ)
0.047, 0.051
1.34
7994
7546
4260 (>6σ)
0.048, 0.057
1.61
R,a Rw
a
GOFa
refinement program
no. of ref params (Np)
weighting scheme
g (2nd ext coeff) × 10e4
SHELXTL-PLUS
556
SHELXTL-PLUS
893
SHELXTL-PLUS
497
SHELXTL-PLUS
429
[σ2(Fo) + 0.0004Fo
0
]
[σ2(Fo) + 0.0014Fo
0.0024(2)
0.94
]
[σ2(Fo) + 0.00014Fo
0.00027(3)
0.95
]
[σ2(Fo) + 0.0002Fo
0.00011(2)
0.95
]
2
-1
2
-1
2
-1
2 -1
(
(
F)max, eÅ-3
F)min, eÅ-3
0.72
-0.77
-0.60
-0.51
-0.93
a
2
R ) [∑||Fo| - |Fc||/∑|Fo]. Rw ) [∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2. GOF ) [∑w(|Fo| - |Fc|)2/(No - Np)]1/2
.
molecule of CH2Cl2, which was later confirmed by the elemen-
tary analysis results and the 1H NMR spectral evidence.
Yield: 63%. Anal. Calcd for C63H58Cl2N4O2P4Ru2: C, 58.11;
H, 4.64; N, 4.30. Found: C, 58.14; H, 4.67; N, 4.40. 1H NMR
(25 °C, 200 MHz, CDCl3): dppm at 7.71-6.99 (m, 40 H), 4.95
(m, 4 H); H4 on µ-Pz′ at 5.44 (br, 2 H); Me3 and Me5 on µ-Pz′
+
+

Diruthenium Carbonyl Complexes
Organometallics, Vol. 15, No. 13, 1996 2987
at 2.10 (s, 6 H), 1.15 (s, 6 H). 31P{1H} NMR (25 °C, 162 MHz,
CH2Cl2/MeOH gave 105 mg of pure solid. It was identified as
[Ru2(CO)4(MeCN)4(PPh3)2][BF4]2 by comparing the spectral
evidences with those reported.4 Yield: 88%.
CDCl3): 11.41 (m, 2 P), -30.26 (m, 2 P). IR (CH2Cl2): vCO
,
1914 s, 1892 s cm-1
.
Rea ction betw een 1-3 a n d N-N (N-N ) bp y, p h en ).
A typical reaction is shown as follows. In a 100-mL Schlenk
flask was added 1 (205 mg, 0.350 mmol), bpy (116 mg, 0.742
mmol), and 25 mL of MeOH at room temperature. The
mixture was then heated under reflux for 5 h and then cooled
to room temperature. A 252 mg amount of NaBPh4 (0.732
mmol) dissolving in 10 mL of MeCN was added to the mixture,
forming a precipitate within 30 min. The solvents were
removed under vacuum. Recrystallization from CH2Cl2/MeOH
gave crude product, which was then washed three times each
with 5 mL of MeOH and 5 mL of Et2O to remove completely
the unreacted bpy and dried in vacuo to give 207 mg of pure
[Ru2(µ-Pz)(µ-CO)2(CO)2(µ1,η2-bpy)2][BPh4] (12) (58%). Anal.
Rea ction betw een 4 a n d I2. In a 100-mL Schlenk flask
was added 4 (107 mg, 0.110 mmol) and 5 mL of CH2Cl2 at room
temperature. This solution was then added dropwise with a
CH2Cl2 solution of I2, prepared by dissolving 2 equiv of I2 (ca.
0.060 g) in 5 mL of CH2Cl2. The mixture was stirred for 0.5
h, and the solvent was then removed under vacuum. Recrys-
tallization from CH2Cl2/MeOH afforded 0.108 g of the pure
product [Ru2(µ-Pz)2(µ-I)(CO)4(PPh3)2][I3] (16) in 73% yield.
Anal. Calcd for C46H36I4N4O4P2Ru2: C, 37.32; H, 2.45; N, 3.78.
Found: C, 37.56; H, 2.54; N, 3.92. 1H NMR (25 °C, 200 MHz,
acetone-d6): PPh3 at 7.79-7.53 (m, 30 H); H3 and H5 on µ-Pz
at 6.99 (d, 4 H, J ) 2.3); H4 on µ-Pz at 5.74 (t, 2 H). 31P{1H}
NMR (25 °C, 162 MHz, acetone-d6): 38.74 (s, 2 P). IR: vCO
,
2072 s, 2024 s cm-1 in CH2Cl2; vCO, 2068 s, 2016 s cm-1 in
KBr.
Calcd for
C51H39BN6O4Ru2: C, 60.47; H, 3.88; N, 8.29.
Found: C, 60.27; H, 3.78; N, 8.14. 1H NMR (25 °C, 200 MHz,
acetone-d6): bpy at 10.16 (m, 4 H), 8.92 (m, 4 H), 8.50 (m, 4
H), 8.14 (m, 4 H); BPh4 at 7.35 (m, 8 H), 6.87 (m, 8 H), 6.75
(m, 4 H); H3 and H5 on µ-Pz at 5.80 (d, 2 H, J ) 2.2); H4 on
µ-Pz at 5.29 (t, 1 H). IR (CH2Cl2): vCO, 2028 s, 1994 w, 1801
w, 1746 s cm-1. A similar reaction between 1 and phen gave
[Ru2(µ-Pz)(µ-CO)2(CO)2(µ1,η2-phen)2][BPh4] (13) (68%). Anal.
Sin gle-Cr ysta l X-r a y Diffr a ction Stu d ies of 2, 5, 10-
12, a n d 14-16. Suitable single crystals were grown from CH2-
Cl2/hexane or CH2Cl2/Et2O at room temperature to do the
single-crystal structure determination. The X-ray diffraction
data for 2, 5, 10, and 16 were measured on a four-circle
diffractometer, and those for 11, 12, 14, and 15 were measured
in frames with increasing ω (0.3°/frame) and with the scan
speed at 10.00 s/frame on a Siemens SMART-CCD instrument,
equipped with a normal focus and 3 kW sealed-tube X-ray
source. For data collected on the four-circle diffractometer,
three standard reflections were monitored every 1 h or every
50 reflections throughout the collection. The variation was
less than 2%. Empirical absorption corrections were carried
out on the basis of an azimuthal scan. For 2, the structure
was solved by direct methods and refined by a full-matrix
least-squares procedure using TEXSAN.8 For 5 and 10, the
structures were solved by heavy-atom method and refined by
a full-matrix least-squares procedure using NRCVAX.9 For 11,
12, and 14-16, the structures were solved by direct methods
and refined by a full-matrix least-squares procedure using
SHELXTL-PLUS.10 The other essential details of single-
crystal data measurement and refinement are given in Table
2. One molecule of CH2Cl2 was found in the asymmetric unit
of the crystals used for 11, 12, and 14, whereas one and a half
molecules of CH2Cl2 were located for 16. The solvent hydrogen
positions in this structure were not included in the structure
refinement.
Calcd for
C55H39BN6O4Ru2: C, 62.26; H, 3.71; N, 7.92.
Found: C, 62.03; H, 3.46; N, 8.02. 1H NMR (25 °C, 200 MHz,
acetone-d6): phen at 10.50 (dd, 4 H, J ) 1.4, 5.2), 9.11 (dd, 4
H, J ) 1.4, 8.2), 8.49 (dd, 4 H, J ) 5.2, 8.2), 8.46 (s, 4 H); BPh4
at 7.34 (m, 8 H), 6.92 (m, 8 H), 6.75 (m, 4 H); H3 and H5 on
µ-Pz at 5.34 (d, 2 H, J ) 2.0); H4 on µ-Pz at 5.06 (t, 1 H). IR
(CH2Cl2): vCO, 2028 s, 1994 w, 1801 w, 1746 s cm-1. Following
a procedure similar to that for 12, the reaction of 2 and 3 with
bpy in the presence of NaPF6 gave only one identical product
[Ru2(µ-Pz′)(µ-CO)2(CO)2(µ1,η2-bpy)2][PF6] (14) in 73 and 85%
yield, respectively. Anal. Calcd for C29H23F6N6O4PRu2: C,
1
40.19; H, 2.67; N, 9.69. Found: C, 39.88; H, 2.81; N, 9.80. H
NMR (25 °C, 200 MHz, CDCl3): bpy at 10.24 (m, 4 H), 8.67
(m, 4 H), 8.38 (m, 4 H), 7.95 (m, 4 H); H4 on µ-Pz′ at 4.84 (s,
1 H); Me3 and Me5 on µ-Pz′ at 3.50 (br, 6 H). IR (CH2Cl2):
v
CO, 2027 s, 1992 w, 1800 w, 1743 s cm-1
. Following a
procedure similar to that for 12, the reaction of 2 and 3 with
phen in the presence of NaPF6 gave only one identical product
[Ru2(µ-Pz′)(µ-CO)2(CO)2(µ1,η2-phen)2][PF6] (15) in 78 and 80%
yield, respectively. Anal. Calcd for C33H23F6N6O4PRu2: C,
1
43.33; H, 2.53; N, 9.18. Found: C, 43.28; H, 2.60; N, 9.37. H
NMR (25 °C, 200 MHz, CDCl3): phen at 10.65 (d, 4 H, J )
5.2), 9.20 (d, 4 H, J ) 8.2), 8.62 (dd, 4 H, J ) 5.2, 8.2), 8.54 (s,
4 H); H4 on µ-Pz′ at 4.78 (s, 1 H); Me3 and Me5 on µ-Pz′ at 2.81
(s, 6 H). IR (CH2Cl2): vCO, 2026 s, 1991 w, 1801 w, 1744 s
Ack n ow led gm en t. Financial support for this work
by the National Science Council of Republic of China
(Contract NSC85-2113-M006-012) is gratefully acknowl-
edged.
cm-1
.
-
Rea ction betw een Et3O+BF 4 a n d 1-3. A typical reac-
tion is shown as follows. To the solution of 1, prepared by
dissolving 1 (100 mg, 0.171 mmol) in 1 mL of MeCN and 10
mL of CH2Cl2 in a 100-mL Schlenk flask, was added with 1
mL of Et3O+BF4- solution (1 M in CH2Cl2). The mixture was
then stirred for 1 h at room temperature, giving a solution IR
spectrum with three typical carbonyl stretching bands at 2062
m, 2033 s, and 1993 s cm-1 for [Ru2(CO)4(MeCN)6][BF4]2,4
which can be converted into [Ru2(CO)4(MeCN)4(PPh3)2][BF4]2
by following the established procedure.4a Yield: 90%.
Su p p or tin g In for m a tion Ava ila ble: An ORTEP plot for
14B (Figure 9) and tables of non-hydrogen atomic coordinates
and equivalent isotropic displacement coefficients, complete
bond lengths and angles, anisotropic displacement coefficients,
and hydrogen coordinates and B values for 2, 5, 10-12, and
14-16 (58 pages). Ordering information is given on any
current masthead page.
OM9600708
-
Rea ction betw een Et3O+BF 4 a n d 4-6. A typical reac-
tion is shown as follows. To the solution of 4, prepared by
dissolving 5 (100 mg, 0.101 mmol) in 10 mL of CH2Cl2 and 1
mL of MeCN in a 100-mL Schlenk flask, was added with 0.5
mL of Et3O+BF4- solution (1 M in CH2Cl2). The mixture was
(8) Crystal Structure Analysis Package, Molecular Structure Corp.,
The Woodlands, TX, 1985, 1992.
(9) Gabe, E. J .; Le page, Y.; Charland, J .-P.; Lee, F. L.; White, P. S.
J . Appl. Crystallogr. 1989, 22, 384.
(10) (a) Sheldrick, G. M. SHELXTL-Plus Crystallographic System,
release 4.21; Siemens Analytical X-ray Instruments: Madison, WI,
1991. (b) Siemens Analytical X-ray Instruments Inc., Karlsruhe,
Germany, 1991.
then stirred for 2 h at room temperature, and 5 mL of MeOH
-
was added to decompose unreacted Et3O+BF4
.
Volatile
substance was removed under vacuum. Recrystallization from
+
+