Metallacycle expansion by alkyne insertion. Chemistry of a new family of ruthenium organometallics

Article abstract of DOI:10.1021/om970917f

Acetylene and phenylacetylene reacts with carbonylchloro[4-methyl-6-((R-imino)methyl)-phenolato-C,O] bis(triphenylphosphine)ruthenium(II), Ru(RL¹)(PPh₃)₂(CO)Cl (3), affording the inserted product carbonylchloro[2-vinyl-4-methyl-6-((R-imino)methyl)phenolato-C,O]bis- (triphenylphosphine)ruthenium(II), Ru(RL²,X)(PPh³)₂(CO)Cl (4), in virtually quantitative yield. The X-ray structures of 4b (R = X = Ph) and 4g (R = Et, X = H) have revealed the presence of distorted-octahedral RuC₂P₂ClO coordination spheres. In the conversion 3 → 4, the Ru(C,O) chelate ring expands from four-membered to six-membered. The insertion of phenylacetylene is regiospecific, and a reaction model implicating initial Ru-O cleavage and steric control is proposed. The Ru-O bond in 4 is significantly shorter (by ～0.14 ?) and stronger than that in 3. This is reflected in the lowering of the ruthenium(III)-ruthenium(II) reduction potential by ～200 mV. The uncoordinated Schiff base moiety in 4 is present in the hydrogen-bonded iminium-phenolato zwitterionic form, as revealed by the N?O distance as well as by IR and NMR data.

Full text of DOI:10.1021/om970917f

1956
Organometallics 1998, 17, 1956-1960
Meta lla cycle Exp a n sion by Alk yn e In ser tion . Ch em istr y
of a New F a m ily of Ru th en iu m Or ga n om eta llics
Kaushik Ghosh, Sujay Pattanayak, and Animesh Chakravorty*
Department of Inorganic Chemistry, Indian Association for the Cultivation of Science,
Calcutta 700 032, India
Received October 21, 1997
Acetylene and phenylacetylene reacts with carbonylchloro[4-methyl-6-((R-imino)methyl)-
phenolato-C,O]bis(triphenylphosphine)ruthenium(II), Ru(RL1)(PPh3)2(CO)Cl (3), affording
the inserted product carbonylchloro[2-vinyl-4-methyl-6-((R-imino)methyl)phenolato-C,O]bis-
(triphenylphosphine)ruthenium(II), Ru(RL2,X)(PPh3)2(CO)Cl (4), in virtually quantitative
yield. The X-ray structures of 4b (R ) X ) Ph) and 4g (R ) Et, X ) H) have revealed the
presence of distorted-octahedral RuC2P2ClO coordination spheres. In the conversion 3 f 4,
the Ru(C,O) chelate ring expands from four-membered to six-membered. The insertion of
phenylacetylene is regiospecific, and a reaction model implicating initial Ru-O cleavage
and steric control is proposed. The Ru-O bond in 4 is significantly shorter (by ∼0.14 Å)
and stronger than that in 3. This is reflected in the lowering of the ruthenium(III)-
ruthenium(II) reduction potential by ∼200 mV. The uncoordinated Schiff base moiety in 4
is present in the hydrogen-bonded iminium-phenolato zwitterionic form, as revealed by
the N‚‚‚O distance as well as by IR and NMR data.
In tr od u ction
which are known.2,3d,9-13 Herein we describe the new
insertion reaction stated in eq 1, where the four-
The insertion of atoms and small unsaturated mol-
ecules into metal-carbon bonds is of abiding interest
in chemical research. In the particular case of alkyne
insertionsa reaction first observed in the form of metal-
promoted oligomerization1,2sthe net outcome of the
primary process and secondary reactions that frequently
follow is the formation of new metal-carbon, carbon-
carbon, and/or carbon-nonmetal bonds. This makes
alkyne insertion a potentially versatile tool for organo-
metallic and organic synthesis.3-8
membered metallacycle 1 is expanded to the six-
membered type 2. The structure and properties of a
family of hitherto unknown organometallics incorporat-
ing 2 are reported. The pathway of the reaction of eq 1
is scrutinized.
The concern of the present work is alkyne insertion
into ruthenium-carbon bonds, several instances of
(1) (a) Keim, W. J . Organomet. Chem. 1969, 16, 191. (b) Ricci, J . S.;
Ibers, J . A. J . Organomet. Chem. 1971, 27, 261. (c) Maitlis, P. M. Acc.
Chem. Res. 1976, 9, 93. (d) Mague, J . T.; Wilkinson, G. Inorg. Chem.
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Resu lts a n d Discu ssion
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Trans. 1977, 621. (c) Bruce, M. I.; Gardner, R. C. F.; Stone, F. G. A. J .
Chem. Soc., Dalton Trans. 1979, 906.
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to the metal in the M-C bond undergoing insertion. Pd-C: (a) Tao,
W.; Silverberg, L. J .; Rheingold, A. L.; Heck, R. F. Organometallics
1989, 8, 2550. (b) Larock, R. C.; Doty, M. J .; Cacchi, S. J . Org. Chem.
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tallics 1996, 15, 3509. (d) Spencer, J .; Pfeffer, M.; Kyritsakas, N.;
Fischer, J . Organometallics 1995, 14, 2214. (e) Pfeffer, M. Pure Appl.
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Teuben, J . H.; Smeets, W. J . J .; Spek, A. L. Organometallics 1996, 15,
2523. (b) Moore, M.; Gambarotta, S.; Yap, G.; Liable-Sands, L. M.;
Rheingold, A. L. J . Chem. Soc., Chem. Commun. 1997, 643.
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Tremont, S. J . J . Org. Chem. 1989, 54, 669. (b) Grigsby, W. J .; Main,
L.; Nicholson, B. K. Organometallics 1993, 12, 397.
Th e New F a m ily. The precursor complexes incor-
porating the chelate ring 1 are of the type Ru(RL1)-
(PPh3)2(CO)Cl (3), formed by decarbonylative metalation
of 4-methyl-2,6-diformylphenol by Ru(PPh3)3Cl2 in the
(7) Ni-C: (a) Yang, K.; Bott, S. G.; Richmond, M. G. Organometallics
1994, 13, 3767. (b) Carmona, E.; Gutierrez-Puebla, E.; Monge, A.;
Marin, J . M.; Paneque, M.; Poveda, M. L. Organometallics 1989, 8,
967. (c) Martinez, M.; Muller, G.; Panyella, D.; Rocamora, M.; Solans,
X.; Font-Bardia, M. Organometallics 1995, 14, 5552. (d) Arlen, C.;
Pfeffer, M.; Fischer, J .; Mitschler, A. J . Chem. Soc., Chem. Commun.
1983, 928.
(8) Schore, N. E. Chem. Rev. 1988, 88, 1081.
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(10) Garn, D.; Knoch, F.; Kish, H. J . Organomet. Chem. 1993, 444,
155.
(11) Ferstl, W.; Sakodinskaya, I. K.; Beydoun-Sutter, N.; Borgne,
G. L.; Pfeffer, M.; Ryabov, A. D. Organometallics 1997, 16, 411.
(12) Bruce, M. I.; Catlow, A.; Cifuentes, M. P.; Snow, M. R.; Tiekink,
E. R. T. J . Organomet. Chem. 1990, 397, 187.
(13) Lutsenko, Z. L.; Aleksandrov, G. G.; Petrovskii, P. V.; Shubina,
E. S.; Andrianov, V. G.; Struchkov, Yu. T.; Rubezhov, A. Z. J .
Organomet. Chem. 1985, 281, 349.
(6) Fe-C: Butler, I. R. Can. J . Chem. 1990, 68, 1979.
S0276-7333(97)00917-5 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 04/15/1998

Metallacycle Expansion by Alkyne Insertion
Organometallics, Vol. 17, No. 10, 1998 1957
F igu r e 2. Perspective view and atom-labeling scheme for
4b‚CH2Cl2 (excluding CH2Cl2).
F igu r e 1. Alkyne-inserted organometallics synthesized in
the present work.
presence of primary amines (RNH2).14 The four-
membered ring in 3 is known to undergo facile cleavage
by ligands,15,16 and this prompted us to explore the
possible reactivity of 3 toward alkynes. A smooth and
virtually quantitative reaction is indeed observed (eq
2) in a boiling dichloromethane-methanol mixture,
F igu r e 3. Perspective view and atom-labeling scheme for
4g.
represents a rare11 example of straightforward two-
carbon metallacycle expansion uncomplicated by sub-
sequent reactions.
1
+
Ru(RL )(PPh3)2(CO)Cl
The type 4 species are diamagnetic and soluble in
halocarbon solvents, affording green (R ) aryl) or pink
(R ) alkyl) solutions. An allowed band in the 500-600
nm range (the range for the corresponding band in 3 is
480-540 nm14) is assigned to a t2 f π* MLCT transition
which is blue shifted by ∼60 nm on going from R ) aryl
3
2
HCtCX f
(2)
Ru(RL ,X)(PPh3)2(CO)Cl
4
X ) H, Ph
1
to R ) alkyl. In H NMR the olefinic CdCH(Ru) protons
affording the insertion product Ru(RL2,X)(PPh3)2(CO)-
Cl (4), which incorporates ring 2. The alkynes used are
acetylene and phenylacetylene. The eight species of
type 4 (4a -h ) are listed in Figure 1.
In previous studies only substituted acetylenes have
been inserted into ruthenium-carbon bonds.2,3d,9-13
Acetylene itself is successfully employed here (eq 2, X
) H) for the first time.17 The reaction of eq 2 also
resonate in the range δ 6.0-6.4 (J HH ≈ 9 Hz for X )
H).
Str u ctu r e. The X-ray structures of two representa-
tive compounds, viz. 4b‚CH2Cl2 and 4g, have been
determined, authenticating the insertion process. Mo-
lecular views are shown in Figures 2 and 3, and bond
parameters are listed in Table 1. The RuC2P2ClO
coordination sphere is distorted octahedral. The corre-
sponding bond parameters of the two complexes are
similar. The (σ-vinyl)phenolato chelate ring along with
the benzene ring and the aldimine function (R and Me
excluded), constitutes a good plane (mean deviation: 4b‚
CH2Cl2, 0.03 Å; 4g, 0.06 Å). The aryl rings at C9 and
N in 4g make dihedral angles of 122.5 and 24.8°,
respectively, with the above plane.
(14) (a) Ghosh, P.; Bag, N.; Chakravorty, A. Organometallics 1996,
15, 3042. (b) Bag, N.; Choudhury, S. B.; Pramanik, A.; Lahiri, G. K.;
Chakravorty, A. Inorg. Chem. 1990, 29, 5013. (c) Bag. N.; Choudhury,
S. B.; Lahiri, G. K.; Chakravorty, A. J . Chem. Soc., Chem. Commun.
1990, 1626.
(15) Ghosh, P.; Pramanik, A.; Chakravorty, A. Organometallics
1996, 15, 4147.
(16) (a) Ghosh, P.; Chakravorty, A. Inorg. Chem. 1997, 36, 64. (b)
Pramanik, K.; Ghosh, P.; Chakravorty, A. J . Chem. Soc., Dalton Trans.,
in press.
(17) Acetylene has however been inserted into the Ru-Si bond:
Maddock, S. M.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J .
Organometallics 1996, 15, 1793.
The average Ru-C10 distance (2.034(10) Å) is slightly
shorter than the usual Ru-C(σ-vinyl) lengths (∼2.1 Å).
The Ru-P, Ru-Cl, and Ru-C(carbonyl) lengths lie close

1958 Organometallics, Vol. 17, No. 10, 1998
Ghosh et al.
Ta ble 1. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) a n d Th eir Estim a ted Sta n d a r d Devia tion s
for Ru (EtL2,H)(P P h 3)2(CO)Cl‚CH2Cl2 (4b‚CH2Cl2)
a n d Ru (P h L2,P h )(P P h 3)2(CO)Cl (4g)
Hz) corresponding to trans disposition of the protons as
in 5. For R ) alkyl species, the azomethine hydrogen
is still a doublet but the N+-H signal is broadened,
presumably due to additional coupling with alkyl pro-
tons (on R-carbon).
4b‚CH2Cl2
4g
Distances
2.536(3)
2.040(9)
2.372(3)
2.372(3)
2.095(7)
1.809(10)
1.287(12)
1.149(12)
1.236(21)
1.352(13)
2.556(12)
Regiosp ecificity: A Rea ction Mod el. The reaction
of eq 2 is not hindered by the presence of large excesses
(10- to 50-fold) of either chloride (LiCl/Et4NCl) or PPh3
in the reaction solution. Therefore, the reaction does
not appear to proceed via equilibrium dissociation of
halide or phosphine ligands. Another crucial feature
of the reaction is that phenylacetylene inserts regiospe-
cifically, the tCPh and tCH carbons adding respec-
tively to the carbon and metal ends of the Ru-C bond
of 3. In this manner the Ph group gets positioned anti
to the metal site in 4 and is distanced from both PPh3
and Cl. Interestingly, diphenylacetylene fails to insert
into 3 under the conditions used for acetylene and
phenylacetylene. These findings are indicative of a
dominant steric control of the reaction path.
The Ru-O(phenolato) bond in 3 is known to be long
(∼2.24 Å),9 being subject to facile reversible cleavage
by ligands.14-16,20 The initial π-anchoring of the alkyne
to the metal is believed to be attended with Ru-O
cleavage, as in 6.20 Subsequent 2 + 2 alkyne addition
to the Ru-C bond is subject to steric crowding from the
Cl and PPh3 ligands (see 7).21,22
Ru-Cl
Ru-C10
Ru-P1
Ru-P2
Ru-O1
Ru-C11
O1-C1
O2-C11
N-C8
2.540(3)
2.029(10)
2.372(3)
2.396(3)
2.100(7)
1.803(11)
1.292(12)
1.175(14)
1.323(15)
1.346(13)
2.639(13)
C9-C10
O1...N
Angles
92.7(1)
163.4(3)
88.8(3)
77.5(2)
88.0(3)
175.8(1)
101.2(3)
95.3(4)
91.0(2)
85.9(3)
178.7(4)
179.5(7)
Cl-Ru-P1
95.2(1)
167.0(3)
88.9(4)
81.5(2)
90.5(3)
176.0(1)
98.8(4)
93.0(5)
90.9(2)
86.8(3)
179.7(5)
175.9(10)
Cl-Ru-C10
P1-Ru-C11
Cl-Ru-O1
P1-Ru-C10
P1-Ru-P2
Cl-Ru-C11
C10-Ru-C11
P1-Ru-O1
O1-Ru-C10
O1-Ru-C11
Ru-C11-O2
to those in type 3 precursor complexes.14 On the other
hand, the average Ru-O1 length (2.098(7) Å) in 4b ‚
CH2Cl2 and 4g is significantly shorter than that in the
type 3 complex Ru(MeC6H4L1)(PPh3)2(CO)Cl (2.235(4)
Å).14b Evidently the four-membered chelate ring of 3
is quite strained. Ring expansion via alkyne insertion
increases the chelate bite angle from ∼64° to ∼87°, and
the Ru-O(phenolato) bond becomes correspondingly
shorter and stronger.
Th e Zw itter ion ic Im in iu m -P h en ola to F u n ction .
The N‚‚‚O1 lengths in 4b‚CH2Cl2 and 4g (2.56(12) and
2.64(13) Å, respectively) are indicative of hydrogen
bonding. The presence of the zwitterionic fragment 5
The bulky tCPh end of phenylacetylene therefore
adds to the carbon site. After insertion, the Ru-O bond
is reestablished as in 4. The inertness of diphenyl-
acetylene to insertion is consistent with this model.
Oxid ized Sp ecies. Organometallics incorporating
trivalent ruthenium are scarce,23 and this prompted us
to explore the feasibility of generating ruthenium(III)
congeners of 4. In dichloromethane solution 4 was
indeed found to display a quasireversible one-electron
cyclic voltammetric response (eq 3) with E1/2 in the
range 0.3-0.4 V vs SCE (Table 2).
The E1/2 values for X ) Ph species are lower by 20-
30 mV than those of the corresponding X ) H species,
as expected. Significantly, the E1/2 values are much
lower (by ∼200 mV) than those of the corresponding
is consistent with IR and 1H NMR data. The N+-H
stretch occurs as a broad band of medium intensity in
the region 3400-3440 cm-1, suggesting the presence of
relatively weak hydrogen bonding.14,18 The CdN stretch-
ing frequency is relatively high (1620-1640 cm-1), and
this is consistent with the protonation of nitrogen.14,18,19
In compounds with R ) aryl the iminium (δ 11.9-
12.6; the signal disappears upon shaking with D2O) and
the azomethine (δ 6.9-7.4) 1H signals are mutually split
into well-resolved doublets, the coupling constant (∼20
(20) To exclude steric repulsion between the entering ligand and
the displaced phenolic oxygen, the cleavage process is associated with
a 180° rotation of the RL1 ligand around the Ru-C bond,15,16 as implied
in 6.
(18) (a) Sandorfy, C.; Vocelle, D. Mol. Phys., Chem., Biol. 1989, 4,
195. (b) Chevalier, P.; Sandorfy, C. Can. J . Chem. 1960, 38, 2524. (c)
Favrot, J .; Vocelle, D.; Sandorfy, C. Photochem. Photobiol. 1979, 30,
417.
(19) Bohme, H.; Haake, M. In Advances in Organic Chemistry;
Bohme, H., Viehe, H. G., Eds.; Interscience: New York, 1976; Part 1,
Vol. 9, p 1.
(21) Diagram 7 was generated using coordinates of solved struc-
tures9 of type 3 using the programs of SHELXTL-Plus.22
(22) Sheldrick, G. M. SHELXTL-Plus Structure Determination
Software Programs; Siemens Analytical X-ray Instruments Inc.,
Madison, WI, 1990.
(23) Ghosh, P.; Pramanik, A.; Bag, N.; Lahiri, G. K.; Chakravorty,
A. J . Organomet. Chem. 1993, 454, 237 and references therein.

Metallacycle Expansion by Alkyne Insertion
Organometallics, Vol. 17, No. 10, 1998 1959
photometers. For 1H NMR spectra a Bruker 300 MHz FT
NMR spectrophotometer was used (tetramethylsilane is the
internal standard). Magnetic properties were examined using
a PAR 155 vibrating-sample magnetometer fitted with a
Walker Scientific magnet. Microanalyses (C,H,N) were done
by using a Perkin-Elmer 240C elemental analyzer. Electro-
chemical measurements were performed under a nitrogen
atmosphere using a PAR 370-4 electrochemistry system. All
potentials reported in this work are uncorrected for junction
contribution.
P r ep a r a tion of Com p lexes. The Ru(RL2,X)(PPh3)2(CO)-
Cl (4) complexes were synthesized in nearly quantitative yields
by reacting Ru(RL1)(PPh3)2(CO)Cl with alkynes. Details are
given for representative cases only.
Ta ble 2. Cyclic Volta m m etr ic Red u ction
P oten tia lsa a t 298 K
E1/2[M(III)-M(II)],b
V (∆Ep, mV)
E1/2[M(III)-M(II)],b
compd
compd
V (∆Ep, mV)
4a
4b
4c
4d
0.35 (120)
0.34 (100)
0.37 (100)
0.39 (130)
4e
4f
4g
4h
0.32 (100)
0.31 (170)
0.38 (160)
0.35(140)
a
Conditions: solvent, dichloromethane; supporting electrolyte,
TEAP (0.1 M); working electrode, platinum; reference electrode,
b
SCE; solute concentration, ∼10-3 M. E1/2 ) 0.5(Epa + Epc) at scan
rate 50 mV s-1, where Epa and Epc are anodic and cathodic peak
potentials, respectively; ∆Ep ) Epa - Epc
.
[Ru (MeL2,H)(P P h 3)2(CO)Cl] (4a ). The orange solution of
Ru(MeL1)(PPh3)2(CO)Cl (50 mg, 0.06 mmol) in a warm 1:4
mixture (50 mL) of dichloromethane and methanol was first
purged with acetylene gas, and then the solution was heated
to reflux for 5 h in an acetylene atmosphere with the help of
a balloon filled with acetylene. The solution turned pink, and
upon concentrating and cooling a pink crystalline solid sepa-
rated, which was collected, washed thoroughly with methanol,
and dried in vacuo. Yield: 51 mg (99%). Anal. Calcd for
RuC48H42NO2P2Cl: C, 66.78; H, 4.87; N, 1.62. Found: C, 66.82;
H, 4.80; N, 1.59. 1H NMR (CDCl3, δ): 6.17 (s, 1H arom), 6.52
(s,1H arom), 7.14-7.62 (m, 30H arom and 1H, CHdC(Ru)),
2.04 (s, 3H, CH3), 6.06 (d, 1H, CdCH(Ru), J HH 9.0 Hz), 12.15
(s, 1H, dN+H), 6.93 (d, 1H, -CHdN+, J HH 11.8), 2.62 (d, 3H,
NCH3, J HH 6.0). IR (KBr, cm-1): ν(CdN) 1640; ν(CtO) 1900;
ν(N-H, hexachlorobutadiene) 3400. UV-vis (CH2Cl2, λmax, nm
(ꢀ, M-1 cm-1)): 520 (2850), 370 (3880), 310 (9830). Complexes
4b-d were prepared using the same procedure as above.
[Ru (EtL2,H)(P P h 3)2(CO)Cl] (4b). Using Ru(EtL1)(PPh3)2-
(CO)Cl (50 mg, 0.058 mmol) a pink crystalline solid of 4b was
RuIII(RL2,X)(PPh3)2(CO)Cl+ + e- h
RuII(RL2,X)(PPh3)2(CO)Cl (3)
couples of complexes of type 3.14a Coordination by the
phenolato group, a hard donor, has been documented
to stabilize trivalent ruthenium.23,24 The lowering of
E
1/2 values of 4 compared to those of 3 is associated with
the strengthening of the Ru-O(phenolato) bond and
formation of the Ru-C(vinyl) bond on going from 3 to
4. The oxidized species in eq 3 were however found to
be still too unstable for isolation via coulometry.
Con clu d in g Rem a r k s
The four-membered chelate ring of 3 smoothly ex-
pands by two carbon atoms upon insertion of acetylene/
phenylacetylene, affording the new organometallic fam-
ily 4. The regiospecificity of phenylacetylene insertion
and the inertness of diphenylacetylene are of steric
origin. This work has provided the first examples of
the insertion of unsubstituted acetylene into the Ru-C
bond.
obtained. Yield: 50 mg (98%). Anal. Calcd for RuC49H44
-
NO2P2Cl: C, 67.08; H, 5.01; N, 1.59. Found: C, 66.98; H, 4.99;
N, 1.63. 1H NMR (CDCl3, δ): 6.22 (s, 1H arom), 6.55 (s, 1H
arom), 7.17-7.61 (m, 30H arom and 1H, -CHdC(Ru)), 2.06
(s, 3H, CH3), 6.08 (d, 1H, CdCH(Ru), J HH 8.9 Hz), 12.25 (s,
1H, dN+H), 6.95 (d, 1H, CHdN+, J HH 11.2), 2.89 (q, 2H, NEt),
1.01 (t, 3H, NEt). IR (KBr, cm-1): ν(CdN) 1640; ν(CtO) 1895;
ν(N-H, hexachlorobutadiene) 3400. UV-vis (CH2Cl2, λmax, nm
(ꢀ, M-1 cm-1)): 520 (3240), 370 (3840), 310 (9490).
The hydrogen-bonded zwitterionic iminium-phenolato
function is retained on going from 3 to 4, even though
during the insertion process the Ru-O bond is believed
to be temporarily cleaved for initial anchoring of the
alkyne. The Ru-O bond length and the t2 f π* MLCT
exitation energy as well as the ruthenium(III)-ruthe-
nium(II) reduction potential systematically decrease on
going from 3 to 4.
[Ru (MeC6H4L2,H)(P P h 3)2(CO)Cl] (4c). Using Ru(MeC6-
H4L1)(PPh3)2(CO)Cl (50 mg, 0.054 mmol) a green crystalline
solid of 4c was obtained. Yield: 50 mg (98%). Anal. Calcd
for RuC54H46NO2P2Cl: C, 69.05; H, 4.90; N, 1.49. Found: C,
68.98; H, 4.96; N, 1.53. 1H NMR (CDCl3, δ): 6.25 (s, 1H arom),
6.52 (s, 1H arom), 7.09-7.65 (m, 34H arom and 1H, CHdC-
(Ru)), 2.06 and 2.30 (2s, 6H, 2CH3), 6.13 (d, 1H, CdCH(Ru),
J HH 9.1 Hz), 12.87 (d, 1H, dN+H, J HH 21.0), 7.37 (d, 1H,
-CHdN+, J HH 20.9). IR (KBr, cm-1): ν(CdN) 1620; ν(CtO)
1990; ν(N-H, hexachlorobutadiene) 3430. UV-vis (CH2Cl2,
The RL2 ligand in 4 is new, and we are trying to
liberate it from 4 via demetalation with the objective of
developing its organometallic chemistry with other
transition metals.
max, nm (ꢀ, M-1 cm-1)): 580 (3560), 428 (7010), 320 (10 460).
[R u (ClC6H 4L2,H )(P P h 3)2(CO)Cl] (4d ). Using Ru(ClC6-
Exp er im en ta l Section
λ
Ma ter ia ls. The starting materials Ru(PPh3)3Cl225 and Ru-
(RL1)(PPh3)2(CO)Cl14 were prepared by reported methods.
Phenylacetylene was obtained from Aldrich. The purification
of dichloromethane and the preparation of tetraethylammo-
nium perchlorate (TEAP) for electrochemical work were done
as described before.26 All other chemicals and solvents were
of analytical grade and were used as received.
H4L1)(PPh3)2(CO)Cl (50 mg, 0.053 mmol) a green crystalline
solid of 4d was obtained. Yield: 50.5 mg (99%). Anal. Calcd
for RuC53H43NO2P2Cl2: C, 66.32; H, 4.48; N, 1.45. Found: C,
66.29; H, 4.50; N, 1.48. 1H NMR (CDCl3, δ): 6.25 (s, 1H arom),
6.58 (s, 1H arom), 7.13-7.76 (m, 34H arom and 1H, CHdC-
(Ru)), 2.06 (s, 3H, CH3), 6.12 (d, 1H, CdCH(Ru), J HH 9.0 Hz),
12.82 (d, 1H, dN+H, J HH 20.9), 7.36 (d, 1H, -CHdN+, J HH
20.7). IR (KBr, cm-1): ν(CdN) 1620; ν(CtO) 1990; ν(N-H,
hexachlorobutadiene) 3430. UV-vis (CH2Cl2, λmax, nm (ꢀ, M-1
cm-1)): 585 (3610), 430 (7380), 320 (12 950).
P h ysica l Mea su r em en ts. Electronic and IR spectra were
recorded with Hitachi 330 and Perkin-Elmer 783 IR spectro-
(24) Lahiri, G. K.; Bhattacharya, S.; Mukherjee, M.; Mukherjee, A.
K.; Chakravorty, A. Inorg. Chem. 1987, 26, 3359.
(25) Stephenson, T. A.; Wilkinson, G. J . Inorg. Nucl. Chem. 1966,
28, 945.
(26) (a) Vogel, A. I. Practical Organic Chemistry, 3rd ed.; ELBS and
Longman Group: Harlow, England, 1965; Chapter 2, pp 176-177. (b)
Sawyer, D. T.; Roberts, J . L., J r. Experimental Electrochemistry for
Chemists; Wiley: New York, 1974; p 212.
[Ru (MeL2,P h )(P P h 3)2(CO)Cl] (4e). To a solution of Ru-
(MeL1)(PPh3)2(CO)Cl (50 mg, 0.06 mmol) in a warm 1:4
mixture (50 mL) of dichloromethane and methanol was added
phenylacetylene (30 mg, 0.30 mmol). The reaction mixture
was heated to reflux for 1.0 h. Upon concentrating and cooling,
a pink colored crystalline solid separated, which was collected,

1960 Organometallics, Vol. 17, No. 10, 1998
Ghosh et al.
Ta ble 3. Cr ysta l, Da ta Collection , a n d Refin em en t
washed thoroughly with methanol, and dried in vacuo. Yield:
56 mg (99%). Anal. Calcd for RuC54H46NO2P2Cl: C, 69.04; H,
4.90; N, 1.49. Found: C, 68.90; H, 4.93; N, 1.51. 1H NMR
(CDCl3, δ): 6.35 (s, 1H arom), 6.89 (s, 1H arom), 7.00-7.60
(m, 33H arom), 1.93 (s, 3H, CH3), 6.27 (s, 1H, CdCH(Ru)),
11.87 (s, 1H, dN+H), 6.95 (d, 1H, -CHdN+, J HH 11.7 Hz), 2.49
(d, 3H, NCH3, J HH 6.0), IR (KBr, cm-1): ν(CdN) 1640; ν(CtO)
1885; ν(N-H, hexachlorobutadiene) 3400. UV-vis (CH2Cl2,
P a r a m eter s for 4b‚CH2Cl2 a n d 4g
4b‚CH2Cl2
4g
mol formula
mol wt
cryst syst
space group
a, Å
C
50H46Cl3NO2P2Ru
C59H48ClNO2P2Ru
1001.4
monoclinic
P21/c
14.845(6)
15.010(4)
22.003(7)
93.57(3)
4922(3)
4
962.2
monoclinic
P21/n
12.129(4)
28.336(9)
13.349(5)
90.29(3)
4587(3)
4
λ
max, nm (ꢀ, M-1 cm-1)): 520 (3940), 360 (5150), 310 (11 200).
b, Å
c, Å
The following complexes (4f-h ) were prepared using the same
procedure as above.
â, deg
V, Å3
[Ru (EtL2,P h )(P P h 3)2(CO)Cl] (4f). Using Ru(EtL1)(PPh3)2-
(CO)Cl (50 mg, 0.058 mmol), a pink crystalline solid of 4f was
Z
λ, Å
0.710 73
6.28
0.710 73
4.84
µ, cm-1
F(000)
Dcalcd, g cm-3
obtained. Yield: 55 mg (99%). Anal. Calcd for RuC55H48
-
1976
2064
NO2P2Cl: C, 69.29; H, 5.03; N, 1.46. Found: C, 69.31; H, 5.06;
N, 1.45. 1H NMR (CDCl3, δ): 6.38 (s, 1H arom), 6.92 (s, 1H
arom), 6.99-7.60 (m, 33H arom), 1.94 (s, 3H, CH3), 6.32 (s,
1H, CdCH(Ru)), 12.01 (s, 1H, dN+H), 6.98 (d, 1H, -CHdN+,
J HH 11.0 Hz), 2.77 (q, 2H, NEt), 0.90 (t, 3H, NEt), 5.84 (d, 2H
arom, J HH 6.0 Hz). IR (KBr, cm-1): ν(CdN) 1640; ν(CtO) 1885;
ν(N-H, hexachlorobutadiene) 3400. UV-vis (CH2Cl2, λmax, nm
(ꢀ, M-1 cm-1)): 520 (3760), 360 (5060), 310 (10 890).
1.396
1.356
o
temp, C
22
22
R,a
%
6.36
6.02
R,b %
7.30
6.94
GOFc
1.27
1.30
a
b
2
R ) ∑||Fo| - |Fc||/∑|Fo|. Rw ) [∑w(||Fo| - |Fc|)2/∑w|Fo| ]1/2
;
w-1 ) σ2|Fo| + g|Fo| ; g ) 0.0005 for 4b‚CH2Cl2 and 0.0003 for 4g.
2
c The goodness of fit is defined as [∑w(|Fo| - |Fc|)2/(no - nv)]1/2
,
[R u (P h L2,P h )(P P h 3)2(CO)Cl] (4g). Using Ru(PhL1)-
(PPh3)2(CO)Cl (50 mg, 0.055 mmol) a green crystalline solid
of 4g was obtained. Yield: 54 mg (98%). Anal. Calcd for
Ru59H48NO2P2Cl: C, 70.76; H, 4.79; N, 1.39. Found: C, 70.71;
H, 4.82; N, 1.41. 1H NMR (CDCl3, δ): 6.42 (s, 1H arom), 7.00
(s, 1H arom), 7.02-7.70 (m, 38H arom), 1.94 (s, 3H, CH3), 6.34
(s, 1H, CdCH(Ru)), 12.63 (d, 1H, dN+H, J HH 21.03 Hz), 7.37
(d, 1H, -CHdN+, J HH 15.0), 5.95 (d, 2H arom, J HH 6.0). IR
(KBr, cm-1): ν(CdN) 1620; ν(CtO) 1920; ν(N-H, hexachlo-
robutadiene) 3440. UV-vis (CH2Cl2, λmax, nm (ꢀ, M-1 cm-1)):
585 (4330), 425 (8400), 320 (12 600).
where no and nv denote the numbers of data and variables,
respectively.
significant intensity reduction in any cases. All data were
corrected for Lorentz-polarization effects, and an empirical
absorption correction27 was done on the basis of an azimuthal
scan of six reflections for each crystal.
In each case the metal atom was located from a Patterson
map and the rest of the non-hydrogen atoms emerged from
successive Fourier synthesis. The structures were refined by
full-matrix least-squares procedures. The NEt group in 4b‚
CH2Cl2 is disordered. All non-hydrogen atoms except for the
NEt group in 4b‚CH2Cl2 were refined anisotropically, and
hydrogen atoms were added at calculated positions with fixed
U ) 0.08 Å2. The highest residuals were 1.43 e Å-3 (4b‚CH2-
Cl2) and 1.07 e Å-3 (4g). All calculations were done on a Micro
Vax II computer using the SHELXTL-PLUS program pack-
age.22 Significant crystal data are listed in Table 3.
[Ru (MeC6H4L2,P h )(P P h 3)2(CO)Cl] (4h ). Using Ru(MeC6-
H4L1)(PPh3)2(CO)Cl (50 mg, 0.054 mmol) a green crystalline
solid of 4h was obtained. Yield: 54 mg (98%). Anal. Calcd
for RuC60H50NO2P2Cl: C, 70.97; H, 4.92; N, 1.37. Found: C,
71.10; H, 4.96; N, 1.41. 1H NMR (CDCl3, δ): 6.41 (s, 1H arom),
7.01 (s, 1H arom), 7.02-7.68 (m, 37H arom), 1.93 and 2.30
(2s, 6H, 2CH3), 6.33 (s, 1H, CdCH(Ru)), 12.64 (d, 1H, dN+H,
J HH 20.1 Hz), 7.35 (d, 1H, -CHdN+, J HH 13.1), 5.96 (d, 2H
arom, J HH 6.0). IR (KBr, cm-1): ν(CdN) 1620; ν(CtO) 1900;
ν(N-H, hexachlorobutadiene) 3440. UV-vis (CH2Cl2, λmax, nm
(ꢀ, M-1 cm-1)): 585 (4040), 425 (8170), 320 (12 960).
Ack n ow led gm en t. We are grateful to the Depart-
ment of Science and Technology, New Delhi, India, the
Indian National Science Academy, New Delhi, India,
and The Council of Scientific and Industrial Research,
New Delhi, India, for financial support. Affiliation with
the J awharlal Nehru Centre for Advanced Scientific
Research, Bangalore, India, is acknowledged.
Attem p ted Rea ction betw een [Ru (MeC6H4L1)(P P h 3)2-
(CO)Cl] a n d Dip h en yla cetylen e. To a solution of Ru-
(MeC6H4L1)(PPh3)2(CO)Cl (50 mg, 0.06 mmol) in a warm 1:4
mixture of dichloromethane and methanol was added diphe-
nylacetylene (107 mg, 0.60 mmol). The reaction mixture was
heated to reflux up to 3.0 h. No green coloration appeared,
and the reaction mixture consisted of starting materials only.
X-r a y Str u ctu r e Deter m in a tion . The single crystals of
Ru(EtL2,H)(PPh3)2(CO)Cl.CH2Cl2 (4b‚CH2Cl2; 0.20 × 0.40 ×
0.40 mm3) and Ru(PhL2, Ph)(PPh3)2(CO)Cl (4g; 0.25 × 0.20 ×
0.30 mm3) were grown (at 298 K) by slow diffusion of hexane
into dichloromethane solution followed by evaporation. Cell
parameters were determined by a least-squares fit of 30
machine-centered reflections (2θ ) 15-30°). Data were col-
lected by the ω-scan technique in the range 3o e 2θ e 45° on
a Siemens R3m/V four-circle diffractometer with graphite-
monochromated Mo KR radiation (λ ) 0.710 73 Å). Two check
reflections measured after every 198 reflections showed no
Su p p or t in g In for m a t ion Ava ila b le: For Ru(EtL2,H)-
(PPh3)2(CO)Cl‚CH2Cl2 (4b‚CH2Cl2) and Ru(PhL2,Ph)(PPh3)2-
(CO)Cl (4g) tables of all bond distances (Tables S1 and S6)
and angles (Tables S2 and S7), anisotropic thermal parameters
(Tables S3 and S8), hydrogen atom positional parameters
(Tables S4 and S9), and non-hydrogen atomic coordinates and
U values (Tables S5 and S10) (13 pages). Ordering informa-
tion is given on any current masthead page.
OM970917F
(27) North, A. C. T.; Phillips, D. C.; Mathews, F. A. Acta Crystallogr.,
Sect. A 1968, A24, 351.