Cationic acetyl complexes of iron(II) and ruthenium(II) bearing neutral N,O ligands: Synthesis, characterization, and interionic solution structure by NOESY NMR spectroscopy

Article abstract of DOI:10.1021/om980460p

The reactions of complexes trans, cis-M(PMe₃)₂(CO)₂(Me)I (M = Fe (1a), Ru (1b)) with N,O ligands [2-acetylpyridine (2-apy), 2-benzoylpyridine (2-bzpy), and 2,2′-dipyridyl ketone (2,2′-dpk)] in the presence of NaBPh₄ afford a mixture of the two possible stereoisomers trans-[M(PMe₃)₂(CO)(COMe)(N, O)]BPh₄ having the N arm cis (A) or trans (B) to the acetyl group. The stereochemistry of the complexes was determined by ¹H NOESY NMR spectra. For all the iron complexes the major stereoisomer is B, while for ruthenium complexes it is A. When A/B mixtures are left in methylene chloride, the concentration of A increases, indicating that A and B are the thermodynamic and kinetic reaction products, respectively. Furthermore, the more basic the N,O ligands, the more B stereoisomer that forms. The solid-state structure of 4b was obtained using single-crystal X-ray diffraction. For all the complexes, the ion-pair structures and the localization of the counterion in solution with respect to the organometallic moiety were investigated by the detection of interionic contacts in the ¹H NOESY NMR spectra. Specific interactions were observed that indicate that the counterion is localized in solution in front of the face determined by PMe₃ and the two arms of the N,O ligands.

Full text of DOI:10.1021/om980460p

Organometallics 1998, 17, 5025-5030
5025
Ca tion ic Acetyl Com p lexes of Ir on (II) a n d Ru th en iu m (II)
Bea r in g Neu tr a l N,O Liga n d s: Syn th esis,
Ch a r a cter iza tion , a n d In ter ion ic Solu tion Str u ctu r e by
NOESY NMR Sp ectr oscop y
Gianfranco Bellachioma,† Giuseppe Cardaci,† Volker Gramlich,‡
Alceo Macchioni,*,† Massimiliano Valentini,† and Cristiano Zuccaccia†
Dipartimento di Chimica, Universita` di Perugia, Via Elce di Sotto 8, I-06123 Perugia, Italy,
and Institut fu¨r Kristallographie und Petrographie, ETH-Zentrum, Sonneggstrasse 5,
CH-8092 Zu¨rich, Switzerland
Received J une 4, 1998
The reactions of complexes trans, cis-M(PMe3)2(CO)2(Me)I (M ) Fe (1a ), Ru (1b)) with
N,O ligands [2-acetylpyridine (2-apy), 2-benzoylpyridine (2-bzpy), and 2,2′-dipyridyl ketone
(2,2′-dpk)] in the presence of NaBPh4 afford a mixture of the two possible stereoisomers
trans-[M(PMe3)2(CO)(COMe)(N, O)]BPh4 having the N arm cis (A) or trans (B) to the acetyl
1
group. The stereochemistry of the complexes was determined by H NOESY NMR spectra.
For all the iron complexes the major stereoisomer is B, while for ruthenium complexes it is
A. When A/B mixtures are left in methylene chloride, the concentration of A increases,
indicating that A and B are the thermodynamic and kinetic reaction products, respectively.
Furthermore, the more basic the N,O ligands, the more B stereoisomer that forms. The
solid-state structure of 4b was obtained using single-crystal X-ray diffraction. For all the
complexes, the ion-pair structures and the localization of the counterion in solution with
respect to the organometallic moiety were investigated by the detection of interionic contacts
1
in the H NOESY NMR spectra. Specific interactions were observed that indicate that the
counterion is localized in solution in front of the face determined by PMe3 and the two arms
of the N,O ligands.
In tr od u ction
insertion of carbon monoxide in compounds trans,cis-
M(PMe3)2(CO)2(Me)I (M ) Fe (1a ) Ru (1b)),3 we realized
that two processes can occur very easily: (1) the
ionization of the M-I bond and (2) the migration of Me
onto a cis CO. Depending on which process occurs first,
it is possible to hypothesize two different reaction
mechanisms (Scheme 1).
There has recently been increased interest in com-
plexes containing “hemilabile” N,O ligands because their
hemilability can facilitate the coordination of a substrate
into the coordination sphere of a transition metal.1
Furthermore, in the case of neutral N,O ligands, the
chelation of the O arm can stabilize reactive species.
Cavell and co-workers demonstrated that Pd compounds
containing N,O ligands can be used to isolate a reaction
intermediate of the ethene insertion.2
If both processes take place, two coordination sites
are left free for the attack of a bidentate ligand.4
Reactions with neutral N,O ligands, where the N arm
is reasonably considered to be the first to coordinate to
the metal, can give interesting information about the
stereochemistry of the reaction and the active mecha-
nism. Second, the reaction of neutral N,O ligands affords
cationic complexes where all but the CO coordination
sites around the metal contain nonequivalent protons.
This makes the formed complexes suitable for studying
their interionic structures in solution by detecting the
Our interest in neutral N,O ligands is based on the
above-mentioned properties and on two other reasons.
First, during the kinetic studies on the migratory
* Corresponding author.
† Universita` di Perugia.
‡ ETH.
(1) For examples, see: (a) Canty, A. J .; Traill P. R.; Skelton, B. W.;
White, A. H. Inorg. Chim. Acta 1997, 255, 117. (b) Frankcombe, K.;
Cavell, K.; Knott, R.; Yates, B. Chem. Commun. 1996, 781. (c)
J ablonski, C.; Zhou, Z.; Bridson, J . Inorg. Chim. Acta1997, 254, 315.
(d) J in, H.; Cavell, K. J .; Skelton, B. W.; White, A. H. J . Chem. Soc.,
Dalton Trans. 1995, 2159. (e) Desjardins, S. Y.; Cavell, K. J .; Hoare,
J . L.; Skelton, B. W.; Sobolev, A. N.; White, A. H.; Keim, W. J .
Organomet. Chem. 1997, 544, 163. (f) Britovsek, G. J . P.; Cavell, K.
J .; Green, M. J . Gerhards, F.; Skelton, B. W.; White, A. H. J .
Organomet. Chem. 1997, 533, 201; Devenson, A. C.; Heath, S. L.;
Harding, C. J .; Powell, A. K. J . Chem. Soc., Dalton Trans. 1996, 3173.
(2) Green, M. J .; Britovsek, G. J . P.; Cavell, K. J .; Skelton, B. W.;
White, A. H. Chem. Commun. 1996, 1563.
1
interionic contacts in the H NOESY spectra.5
(3) (a) Reichenbach, G.; Cardaci, G.; Bellachioma, G.; J . Chem. Soc.,
Dalton Trans. 1982, 847. (b) Bellachioma, G.; Cardaci, G.; Macchioni,
A.; Madami, A. Inorg. Chem. 1993, 32, 554. (c) Bellachioma, G.;
Cardaci, G.; Macchioni, A.; Reichenbach, G. Inorg. Chem. 1992, 31,
3018. (d) Bellachioma, G.; Cardaci, G.; Macchioni, A.; Reichenbach,
G. J . Organomet. Chem. 1992, 427, C37.
(4) (a) Macchioni, A.; Bellachioma, G.; Cardaci, G.; Gramlich, V.;
Ru¨egger, H.; Terenzi, S.; Venanzi, L. M. Organometallics, 1997, 16,
2139. (b) Bellachioma, G.; Cardaci, G.; Gramlich, V.; Macchioni, A.;
Pieroni, F.; Venanzi, L. M. J . Chem. Soc., Dalton Trans. 1998, 947.
10.1021/om980460p CCC: $15.00 © 1998 American Chemical Society
Publication on Web 10/16/1998

5026 Organometallics, Vol. 17, No. 23, 1998
Bellachioma et al.
Sch em e 1
Ch a r t 1
Sch em e 2
Here we report the results of our studies on the
reactivity of complexes 1a ,b with several N,O ligands
that allowed the new complexes 2-7, shown in Chart
1, to be synthesized and the previously reported meth-
odology, based on the nuclear Overhauser effect, has
been extended to investigate the ion-pair solution
structures of organometallic complexes.
Resu lts a n d Discu ssion
Syn th esis a n d Rea ctivity. The reactions of 1a ,b
with N,O ligands in the presence of NaBPh4 afford the
acetyl complexes 2-7 according to Scheme 2.
All ruthenium compounds are dark red, stable in solid
state, and relatively stable in solution, while iron
compounds are violet and stable only in the solid state.
In solution at room temperature they start to decompose
after ca. 5 h. It is interesting to outline that in the case
of the 2,2′-dpk ligand, where there is the possibility of
the coordination of the N,N arms, we also observe the
coordination of the N,O arms. For all ligands, a mixture
of two stereoismers A and B forms in a ratio that is
strongly affected by the metal: A is the preferred
stereoisomer for ruthenium, while B is favored in the
case of iron compounds. Leaving complexes in CH2Cl2
solution, the concentration of stereoisomer A increases
in both iron and ruthenium compounds. The ratios of
the two stereoisomers, as soon as they are dissolved in
CD2Cl2 and after ca. 6 h (evaluated by the integration
(5) (a) Bellachioma, G.; Cardaci, G.; Macchioni, A.; Reichenbach, G.;
Terenzi, S. Organometallics 1996, 15, 4349. (b) For references on
interionic studies of organic salts which catalyze phase-transfer
reactions, see: (b) Pochapsky, T. C.; Wang, A.-P.; Stone, P. M. J . Am.
Chem. Soc. 1993, 115, 11084. (c) Pochapsky, T. C.; Stone, P. M. J . Am.
Chem. Soc. 1990, 112, 6714. (d) Pochapsky, T. C.; Stone, P. M. J . Am.
Chem. Soc. 1991, 113, 1460. For references on interionic studies of
organolithium ion pairs, see: (e) Hoffman, D.; Bauer, W.; Schleyer, P.
v. R. J . Chem. Soc., Chem. Commun. 1990, 208. (f) Bauer, W.; Mu¨ller,
G.; Pi, R.; Schleyer, P. v. R. Angew. Chem., Int. Ed. Engl. 1986, 25,
1103. (g) Bauer, W.; Klusener, P. A. A.; Harder, S.; Kanters, J . A.;
Duisenberg, A. J . M.; Brandsma, L.; Schleyer, P. v. R. Organometallics
1988, 7, 552. (h) Bauer, W.; Clark, T.; Schleyer, P. v. R. J . Am. Chem.
Soc. 1987, 109, 970. (i) Bauer, W.; Feigel, M.; Mu¨ller, G.; Schleyer, P.
v. R. J . Am. Chem. Soc. 1988, 110, 6033.
1
of H and 31P NMR resonances) are reported in Table
1. This results can be explained by considering that B
and A are the kinetic and thermodynamic reaction
products, respectively. It is difficult to establish the
active mechanism because for both mechanisms shown

Cationic FeII and RuII Complexes with Neutral N,O Ligands
Organometallics, Vol. 17, No. 23, 1998 5027
Ta ble 1. Ra tios of th e Tw o Ster eoisom er s A a n d B
(A/B) in CD2Cl2 Deter m in ed by NMR Sp ectr a
M ) Fe
M ) Ru
after ca. 20 h
N,O ligand
after ca. 6 h
2-apy
2-bzpy
2, 2'-dpk
1/9
1/8
1/5
1/3
1/3
1/4
1/1
only A
only A
10/1
only A
only A
Ta ble 2. Exp er im en ta l Da ta for X-r a y Diffr a ction
Stu d y of 4b
empirical formula
mol wt
C45H50BNO3P2Ru
826.7
temperature (K)
system
293
monoclinic
space group
a (Å)
b (Å)
P21/c
15.46(2)
15.259(13)
F igu r e 1. ORTEP view of cationic fragment of 4b.
c (Å)
18.09(2)
100.70(9)
4193(7)
Ta ble 3. Selected Bon d Len gth s (Å) a n d Bon d
An gles (d eg) for 4b
â (deg)
V (Å3)
Z
4
Ru-P(1)
Ru-P(2)
Ru-N
Ru-O(3)
Ru-C(1)
Ru-C(3)
C(1)-O(1)
2.364(3)
2.360(3)
2.198(4)
2.226(4)
2.014(6)
1.832(6)
1.183(7)
C(3)-O(2)
N-C(4)
1.141(6)
1.331(6)
1.368(6)
1.470(7)
1.243(6)
1.478(7)
F(000)
1720
0.710 73
0.49
1.8-20.0
λ(Mo KR) (Å)
N-C(8)
µ(Mo KR) (mm-1
ϑ-range (deg)
index ranges
)
C(8)-C(9)
C(9)-O(3)
C(9)-C(10)
0 e h e 14, 0 e k e 14, -17 e l e 17
4113
3923
no. of measd reflcns
no. of unique reflcns
used in the refinement
no. of refined params
GOF on F2
P(2)-Ru-P(1)
P(1)-Ru-O(3)
P(1)-Ru-N
P(2)-Ru-O(3)
P(2)-Ru-N
Ru-N-C(8)
C(9)-C(8)-N
O(3)-C(9)-C(8)
Ru-O(3)-C(9)
P(1)-Ru-C(1)
P(1)-Ru-C(3)
177.34(6)
91.12(12)
89.09(13)
90.28(12)
89.15(13)
115.7(3)
114.8(4)
118.3(4)
117.2(3)
89.6(2)
P(2)-Ru-C(1)
P(2)-Ru-C(3)
C(1)-Ru-C(3)
O(3)-Ru-C(3)
N-Ru-C(1)
O(3)-Ru-C(1)
N-Ru-C(3)
Ru-C(3)-O(2)
C(9)-C(10)-C(11)
O(3)-C(9)-C(10)
O(3)-Ru-N
88.7(2)
90.6(2)
91.5(3)
485
0.918
0.039
0.099
95.0(2)
R1 (on F, I > 2σ(I)
wR2 (on F2)
100.2(2)
173.4(2)
168.3(2)
176.6(5)
117.7(5)
118.8(5)
73.3(2)
in Scheme 1 the nucleophile (in this case the N arm of
the N,O ligands) occupies the position trans to the
COMe group at the end of the reaction.6 This means
that in both mechanisms B is the kinetic reaction
product. However, previous studies suggest that in the
case of iron, the ionic mechanism is more probable than
in ruthenium.6 Furthermore, the reactivity of ruthe-
nium is about 10 times higher than that of iron;6e this
explains the greater amount of stereoisomer A in
ruthenium compounds. Several synthesis carried out at
233 K demonstrated that the same preferential ratios
remain.
There is also a slight dependence of the A/B ratios
on the type of N,O ligand (see Table 2), particularly
evident in the reaction of compound 1b with 2-apy. This
is the only case where stereoisomer B forms signifi-
cantly with ruthenium and may be due to the better
donor capacity of the oxygen of the ligand that partially
slows down the isomerization process.
Ch a r a cter iza tion a n d Str u ctu r e. (a ) Solid Sta te.
X-ray crystallographic studies of 4b were carried out.
An ORTEP plot of 4b is shown in Figure 1. Tables 2
and 3 show experimental parameters and a list of
selected bond lengths and angles, respectively. The
geometry at ruthenium in this complex is approximately
octahedral. The Ru-O(3) separation is substantially
elongated (2.226(4) Å) compared to similar compounds2,7
91.5(2)
because in trans position of O(3) there is the COMe
group that it is known to exert a high trans-effect.6a Due
to O(3) coordination to the ruthenium, the double bond
C(9)-O(3) (1.243(6) Å) is weakened and is longer than
the C(1)-O(1) bond (1.183(7) Å) but agrees with the
usually reported values.2,7 The five-member ring con-
taining Ru-O(3)-C(9)-C(8)-N atoms is approximately
coplanar with the equatorial ligands. There is however
a remarkable deviation from the coplanarity between
the phenyl group and the above-mentioned five-member
ring. The angle between the least-squares planes through
them is 43.4°. Other bond distances and angles fall
within expected ranges for compounds of this type. The
counterion is positioned close to the CO and O arm of
the N,O ligand. Interionic distances can be evaluated
by adding hydrogens to carbon atoms using standard
values. The more important contacts are as follows:
PMe3, p-H, 2.74 Å; H-2′ and H-3′, m-H and p-H (3.4-
4.0 Å).
(b) Solu tion s. In tr a m olecu la r Str u ctu r e. Char-
acterization of complexes 2-7 in this phase was carried
out by IR and H, 13C, and 31P NMR. The IR spectra of
1
complexes show two bands in the carbonyl stretching
region. The first, due to the COMe ligands, is metal-
insensitive and falls close to 1600 cm-1 and the second,
ν(CO), is at 1955 and 1935 cm-1 for the ruthenium and
iron complexes, respectively, and shows the typical
(6) (a) J ablonski, C. R.; Wang, Y.-P. Inorg. Chem. 1982, 21, 4037.
(b) Cardaci, G.; Reichenbach, G.; Bellachioma, G. Inorg. Chem. 1984,
23, 2936. (c) Cardaci, G.; Reichenbach, G.; Bellachioma, G.; Wassink,
B.; Baird, M. C. Organometallics 1988, 7, 2475. (d) Bellachioma, G.;
Cardaci, G.; Macchioni, A.; Reichenbach, G.; Foresti, E.; Sabatino, P.
J . Organomet. Chem. 1997, 531, 227. (e) Bellachioma, G.; Cardaci, G.;
Macchioni, A.; Reichenbach, G. J . Organomet. Chem. 1997, 540, 7. (f)
Aubert, M.; Bellachioma, G.; Cardaci, G.; Macchioni, A.; Reichenbach,
G.; Burla, M. C. J . Chem. Soc., Dalton Trans. 1997, 1759.
(7) (a) Bacchi, A.; Carcelli, M.; Costa, M.; Pelagatti, P.; Pelizzi, C.;
Pelizzi, G. J . Chem. Soc., Dalton Trans. 1996, 4239. (b) Sommerer, S.;
J ensen, W. P. Inorg. Chim. Acta 1990, 172, 3.

5028 Organometallics, Vol. 17, No. 23, 1998
Bellachioma et al.
F igu r e 2. Section of 1H NOESY spectrum of 2a (A) and 3a (B), recorded at 400.13 MHz in CD2Cl2, showing the interionic
contacts between the COMe groups of the ligands and o-H and p-H protons.
difference of 20 cm-1.8 The CdO stretching band relative
to the N,O ligands falls below 1600 cm-1, and it was
not clearly identified.
Com p lexes 4a a n d 5a . The PMe3 protons show
contacts with o-H and m-H, and H-4 and H-5 with o-H
and m-H, respectively.
The assignment of the proton resonances in different
fragments was obtained by combining information from
Com p lex 4b. H-5, H-4, and one of the H-2′ show
contacts with o-H of BPh4-. The protons of the PMe3
1
1H COSY and H NOESY NMR experiments. The latter
groups show strong contacts with all the protons of
-
experiments also provided the stereochemistry of the
formed isomers. In the case of stereoisomer A, a contact
between H-6 proton (see numeration reported in Chart
1) and the COMe protons was observed. Stereoisomer
B can be identified by the absence of such a contact or
directly from a contact between the COMe, H-2′, or H-3′
protons of the N,O ligand and the COMe proton for
complexes 3a ,b, 5a , or 7a , respectively. As a further
confirmation of the double bond character of the CdO
BPh4
.
Com p lexes 6a a n d 7a . There are strong contacts
-
among the o-H, m-H, and p-H of BPh4 and all the
protons of the ligand. The protons of the PMe3 groups
-
interact with all the protons of the BPh4
.
-
Com p lex 6b. o-H, m-H, and p-H of BPh4 show
contacts only with the protons of PMe3 groups; there
-
are weak contacts among the o-H and m-H of BPh4
and the protons of the ligand.
bond in coordinated N,O ligands, δCO falls close to 200
lig
-
For all complexes, BPh4 is specifically localized in
ppm.
front of the face determined by PMe3 and both arms of
the N,O ligands. As a confirmation of the specificity of
the contacts, we never observed the interionic contact
between the counterion and M-COMe protons. This
agrees with quantomechanical and molecular mechanic
calculations, recently carried out by us on analogous
compounds containing N,N ligands,9 that indicate a
nonspherical distribution of the positive charge. In
particular, the positive charge is partially delocalized
on the rings of N,N ligands, while some negative charge
is accumulated on the COMe group directly bonded to
the metal. Furthermore, owing to the presence in N,N
and N,O ligands of at least one aromatic ring, there is
also an energetic gain from the van der Waals point of
view for the counterion to stay close to such ligands.
In ter ion ic Str u ctu r es. In previous studies4,5a we
showed that it is possible to localize the position of the
counterion in solution by the detection of interionic
contacts, in 1H NOESY spectra, between protons be-
longing to it and some of the “organometallic” protons.
In weak polar solvents (like methylene chloride), where
only intimate ion pairs are present, we observed specific
counterion-cation interactions for iron and ruthenium
compounds4 similar to those here reported having a N,N
instead of N,O bidentate ligands. To see whether
compounds 2-7 in methylene chloride solution also
present specific anion-cation interactions and, conse-
quently, extend the methodology, we recorded the
phase-sensitive 1H NOESY spectra for all of them.
Specific interionic contacts were observed. In particular:
Com p lexes 2a a n d 3a . o-H and m-H of BPh4- show
contacts with COMe of the ligand (see Figure 2) and
H-4. PMe3 protons show contacts with all three types
of counterion protons.
The interionic structure of complex 4b determined by
single-crystal X-ray studies, presents the counterion
between the CO and O arm of the N,O bidentate ligand.
This means that the counterion position is slightly
different than that found in solution where we also
observed contacts between o-H and protons belonging
to the pyridyl ring.
Com p lexes 2b a n d 3b. o-H of BPh4- show contacts
with COMe of the ligand. The protons of the PMe3
groups interact with all the protons of BPh4.
(8) Braterman, P. S. Metal Carbonyl Spectra; Academic Press:
London, 1975.
(9) Macchioni, A.; Bellachioma, G.; Cardaci, G.; Cruciani, G.; Foresti,
E.; Sabatino, P.; Zuccaccia, C. Organometallics, in press.

Cationic FeII and RuII Complexes with Neutral N,O Ligands
Organometallics, Vol. 17, No. 23, 1998 5029
3a : 1H NMR (in CD2Cl2, 298 K, J values in Hz): δ 8.75 (ddtd,
Con clu sion s
4
5
4
3J HH ) 5.2, J HH ≈ J HH ≈ J HP ) 0.5, H-6), 7.70 (m, H-4 AB
3
3
Cationic acetyl complexes 2-7 have been synthesized
from the reaction of hemilabile N,O ligands with com-
pounds 1a ,b and their stereochemistry has been deter-
mined by phase-sensitive 1H NOESY NMR spectros-
copy. Stereoisomers A and B, preferentially formed for
ruthenium and iron, respectively, represent the ther-
modynamic and kinetic reaction products.
The interionic structure of complexes, investigated in
CD2Cl2 by the NOESY NMR spectroscopy, indicates that
the counterion is specifically localized in front of the face
determined by PMe3 and the two arms of the N,O
ligands.
system), 7.67 (m, H-3 AB system), 7.46 (ddd, J HH ) J HH
)
5.3, J HH ) 1.7, H-5), 7.41 (m, o-H), 7.05 (t, J HH ) 3J HH ) 7.3
4
3
m-H), 6.89 (t, 3J HH ) 7.2 p-H), 2.71 (t, 5J HP ) 2.9 COMe of the
2
ligand), 2.63 (s, COMe), 1.04 (Harris t, | J PH
+
4J PH| ) 8.3,
PMe3). 31P{1H} NMR: 15.8 (s, PMe3). 13C{1H} NMR: 276.7 (br,
COMe), 217.9 (t, 2J CP ) 30.1, CO), 206.4 (t, 4J CP ) 3.8 COMelig),
1
164.4 (q, J BC ) 49.1, C-ipso), 153.1 (s, C-2), 150.7 (s, C-6),
139.5 (s, C-5), 136.3 (s, o-C), 131.1 (s, C-4 and C-3), 126.2 (s,
m-C), 122.3 (s, p-C), 49.7 (s, COMe), 25.8 (t, 4J CP ) 5.0 COMelig),
1
3
13.4 (Harris t, | J PC + J PC| ) 27.3, PMe3).
P r ep a r a tion of tr a n s-[Fe(P Me3)2(CO)(COMe)(2-bzp y)]-
BP h 4 (4a a n d 5a ). The procedure was the same as that for
2a and 3a . The solid is a mixture of 4a and 5a in a ratio 1:8
(yield 70%). IR (CH2Cl2): νCO 1943 cm-1; νCOMe 1597 cm-1
.
Complex 4a : 1H NMR (in CD2Cl2, 294 K, J values in Hz): δ
Exp er im en ta l Section
3
3
4
10.33 (d, J HH ) 5.5, H-6), 8.18 (dd, J HH ) 7.6, J HH ) 1.2,
H-3), 2.58 (s, COMe), 1.01 (Harris t, | J PH + 4J PH| ) 8.4, PMe3).
2
Gen er a l Da ta . Complexes 1a and 1b were prepared ac-
cording to the literature.3a,b Reactions were carried out in a
dried apparatus under a dry inert atmosphere of nitrogen
using standard Schlenk techniques. Solvents were purified
prior to use by conventional methods.10 All the ligands were
purchased by Fluka and utilized without further purification.
IR spectra were taken on a 1725 X FTIR Perkin-Elmer
spectrophotometer. One and two-dimensional 1H, 13C, and 31P
NMR spectra were measured on Bruker DPX 200 and DRX
400 spectrometers. Referencing is relative to TMS and external
85% H3PO4. NMR samples were prepared dissolving about 20
mg of compound in 0.5 mL of CD2Cl2, bubbling for 5 min with
dried nitrogen. Two-dimensional 1H NOESY spectra were
measured with a mixing time of 800 ms.
31P{1H} NMR: 17.3 (s, PMe3). 13C{1H} NMR: 275.9 (t, COMe),
220.0 (t, 2J CP ) 29.4, CO), 202.3 (s, COPh), 136.4 (s, o-C), 126.0
(s, m-C), 122.2 (s, p-C), 49.4 (s, COMe). Complex 5a : 1H NMR
(in CD2Cl2, 294 K, J values in Hz): δ 8.85 (d, 3J HH ) 5.2, H-6),
3
3
8.22 (d, J HH ) 8.0, H-3), 7.85 (d, J HH ) 6.8, H-2′), 7.79 (t,
3J HH ) 8.4, H-4′), 7.68 (t, 3J HH ) 7.8, H-3′), 7.64 (d, 3J HH ) 7.6,
3
3
4
H-4), 7.44 (ddd, J HH ) 6.8, J HH ) 5.2, J HH ) 1.2, H-5), 7.33
3
3
(m, o-H), 6.99 (t, J HH ) 7.2, m-H), 6.84 (t, J HH ) 7.2, p-H),
2.69 (s, COMe), 1.05 (Harris t, | J PH + 4J PH| ) 8.4, PMe3). 31P-
2
{1H} NMR: 18.8 (s, PMe3). 13C{1H} NMR: 273.3 (br, COMe),
2
3
217.9 (t, J CP ) 31.1, CO), 199.6 (t, J CP ) 4.3, COPh), 164.5
(q, J BC ) 49.4, C-ipso), 155.4 (s, C-2), 153.9 (s, C-6), 139.8 (s,
1
C-1′), 139.1 (s, C-3), 136.4 (s, o-C), 136.1 (s, C-4), 133.2 (s, C-2′),
130.5 (s, C-4′), 130.2 (s, C-3′), 129.8 (s, C-5), 126.0 (s, m-C),
X-r a y Cr ysta llogr a p h y. Crystals of 4b, suitable for single-
crystal X-ray analysis, were obtained from CH2Cl2/ether/n-
hexane. Diffraction intensities were collected at room temper-
ature by the θ/2θ scan method on a graphite monochromatized
1
3
122.2 (s, p-C), 42.6 (s, COMe), 13.6 (Harris t, | J PC + J PC| )
13.4, PMe3).
P r ep a r a tion oftr a n s-[Fe(P Me3)2(CO)(COMe)(2,2′-d p k )]-
BP h 4 (6a a n d 7a ). The procedure was the same as that for
2a and 3a . The solid is a mixture of 6a and 7a in a ratio 1:5
2
Syntex P21 diffractometer and reduced to Fo values. The
structure was solved by Patterson methods and refined by full-
matrix least-squares calculations. For all computations, the
SHELXTL package of crystallographic programs was used.
Thermal vibrations were treated anisotropically for all non-H
atoms. All H atoms were positioned geometrically (C-H 0.96
Å) and refined with adequate constraints. Final difference
Fourier maps showed residual peaks lower than 1.3 e Å-3 in
the proximity of the Ru atom.
P r ep a r a tion of tr a n s-[F e(P Me3)2(CO)(COMe)(2-a p y)]-
BP h 4 (2a a n d 3a ). 1a (200 mg, 0.49 mmol) was dissolved in
8 mL of CH3OH, and NaBPh4 (large excess) was added.
2-Acetylpyridine (77 mg, 0.64 mmol) was slowly added. Im-
mediately a reddish solid precipitated. The solution was stirred
for an hour. The solid was filtered, washed with cold CH3OH,
and dried. The solid is a mixture of 2a and 3a in a ratio 1:9
(230 mg, yield 65%). Anal. Calcd (found) for C40H49BFeO3-
NP2: H, 1.92 (1.95); C, 62.57 (66.76); N, 6.29 (6.68). IR (CH2-
Cl2): νCO 1937 cm-1; νCOMe 1598 cm-1. Complex 2a : 1H NMR
(yield 68%). IR (CH2Cl2): νCO 1944 cm-1; νCOMe 1599 cm-1
.
Complex 6a : 1H NMR (in CD2Cl2, 298 K, J values in Hz): δ
3
3
10.32(d, J HH ) 4.0, H-6), 9.94 (d, J HH ) 7.9, H-3), 8.83 (d,
3J HH ) 4.5, H-6′), 8.24 (d, J HH ) 7.9, H-3′), 8.15 (m, H-4′),
3
3
4
8.00 (td, J HH ) 5.5, J HH ) 1.2, H-4), 7.91 (m,H-5), 7.65 (m,
3
3
H-5′), 7.33 (m, o-H), 7.02 (t, J HH ) 7.3, m-H), 6.90 (t, J HH
)
2
4
7.1, p-H), 2.63 (s, COMe), 1.02 (Harris t, | J PH + J PH| ) 8.4,
PMe3). 31P{1H} NMR: 15.0 (s, PMe3). 13C{1H} NMR: 268.1 (s,
1
COMe), 215.0 (s, CO), 163.7 (q, J BC ) 49.3, C-ipso), 153.7 (s,
C-6), 150.7 (s, C-2), 150.3 (s, C-2′), 149.3 (s, C-6′), 138.8 (s,
C-5), 138.0 (s, C-5′), 135.6 (s, o-C), 134.2 (s, C-3), 129.7 (s, C-3′),
128.5 (s, C-4), 125.9 (s, C-4′), 125.4 (s, m-C), 121.6 (s, p-C),
1
48.9 (s, COMe), 12.5 (Harris t, | J PC
+
3J PC| ) 25.9, PMe3).
Complex 7a : 1H NMR (in CD2Cl2, 298 K, J values in Hz): δ
3
3
10.07 (d, J HH ) 8.1, H-3), 8.92 (d, J HH ) 5.3, H-6), 8.88 (d,
3J HH ) 4.2, H-6′), 8.47 (d, 3J HH ) 7.9, H-3′) 8.09 (t, 3J HH ) 5.2,H-
3
3
4′), 7.99 (t, J HH ) 5.4,H-4), 7.72 (t, J HH ) 7.9, H-5′), 7.55 (t,
3J HH ) 6.1, H-5), 7.33 (m, o-H), 7.02 (t, J HH ) 7.3, m-H), 6.90
3
3
(in CD2Cl2, 298 K, J values in Hz): δ 10.25 (ddtd, J HH ) 5.6,
3
2
(t, J HH ) 7.1, p-H), 2.75 (s, COMe), 1.06 (Harris t, | J PH
+
4J HH ≈ J HP ) 1.6, J HH ) 0.7, H-6), 7.88 (td, J HH ) J HH
)
4
5
3
3
4J PH| ) 8.5, PMe3). 31P{1H} NMR: 16.9 (s, PMe3). 13C{1H}
4
3
3
4
7.5, J HH ) 1.7, H-4), 7.82 (td, J HH ≈ J HH ) 5.5, J HH ) 1.6,
1
NMR: 272.7 (s, COMe), 217.8 (s, CO), 163.7 (q, J BC ) 49.3,
H-5), 7.72 (dd, 3J HH ) 7.5, 4J HH ) 0.8, H-3), 7.41 (m, o-H), 7.05
C-ipso), 152.6 (s, C-6), 150.6 (s, C-2), 150.3 (s, C-2′), 149.7 (s,
C-6′), 138.3 (s, C-5), 137.9 (s, C-5′), 136.0 (s, C-3), 135.6 (s,
o-C), 130.2 (s, C-3′), 129.2 (s, C-4), 126.2(s, C-4′), 125.4 (s, m-C),
3
3
3
(t, J HH ) J HH ) 7.3 m-H), 6.89 (t, J HH ) 7.2 p-H), 2.60 (t,
5J HP ) 1.9, COMe of the ligand), 2.54 (s, COMe), 0.99 (Harris
t,11 | J PH + J PH| ) 8.3, PMe3). 31P{1H} NMR: 14.6 (s, PMe3).
2
4
1
3
121.6 (s, p-C), 42.5 (s, COMe), 12.8 (Harris t, | J PC + J PC| )
13C{1H} NMR: 274.8 (br, COMe), 220.2 (t, J CP ) 30.1, CO),
2
27.5, PMe3).
207.6 (s, COMelig), 164.4 (q, 1J BC ) 49.1, C-ipso), 154.8 (s, C-2),
149.2 (s, C-6), 140.3 (s, C-5), 136.3 (s, o-C), 130.6 (s, C-4), 129.7
(s, C-3), 126.2 (s, m-C), 122.3 (s, p-C), 50.8 (s, COMe), 26.1 (s,
P r ep a r a tion of tr a n s-[Ru (P Me3)2(CO)(COMe)(2-a p y)]-
BP h 4 (2b a n d 3b). Compound 1b (200 mg, 0.37 mmol) was
dissolved in 8 mL of CH3OH, and NaBPh4 (large excess) was
added. 2-Acetylpyridine (58 mg, 0.48 mmol) was slowly added.
Immediately a pale red solid precipitated. The solution was
stirred for 30 min. The solid was filtered, washed with cold
CH3OH, and dried. The solid is a mixture of 2b and 3b in a
1
COMelig), 13.3 (Harris t, | J PC + 3J PC| ) 26.2, PMe3). Complex
(10) Weissberger, A.; Proskauer, E. S. Technique of Organic Chem-
istry; Interscience: New York, 1955; Vol. VII.
(11) Harris, R. K. Can. J . Chem. 1964, 42, 2275.

5030 Organometallics, Vol. 17, No. 23, 1998
Bellachioma et al.
ratio 1:1 (yield 70%). Anal. Calcd (found) for C40H49BRuO3-
NP2: H, 6.28 (6.41); C, 62.83 (62.84); N, 1.83 (1.92). IR (CH2-
Cl2): νCO 1955 cm-1; νCOMe 1599 cm-1. Complex 2b: 1H NMR
C-3), 140.8 (br, C-1′), 136.3 (s, o-C), 134.7 (s, C-4), 133.3 (s,
C-5), 131.2 (s, C-4′), 130.1 (s, C-2′ and C-3′), 126.1 (s, m-C),
1
3
122.2 (s, p-C), 49.4 (s, COMe), 13.9 (Harris t, | J CP + J CP| )
3
(in CD2Cl2, 298 K, J values in Hz): δ 10.11 (d, J HH ) 4.2,
28.9 PMe3).
3
3
H-6), 7.88 (m, H-5), 7.79 (t, J HH ) 7.2, H-4), 7.70 (d, J HH
)
P r ep a r a t ion of tr a n s-[R u (P Me3)2(CO)(COMe)(2,2′-
d p k )]BP h 4 (6b). The procedure was the same of 2b and 3b
7.9, H-3), 7.47 (m, o-H), 7.02 (t, 3J HH ) 7.3, m-H), 6.87 (t, 3J HH
5
1
) 8.6 p-H), 2.56 (t, J HH ) 3.8, COMelig), 2.52 (s, COMe), 1.00
(yield 66%). IR (CH2Cl2): νCO 1956 cm-1; νCOMe 1607 cm-1. H
(Harris t, | J PH + J PH| ) 7.2, PMe3). 31P{1H} NMR: -3.6 (s,
PMe3). 13C{1H} NMR: 255.9 (br, COMe), 206.5 (s, COMelig),
204.7 (t, 2J CP ) 14.3, CO), 164.7 (q, 1J BC ) 49.2, C-ipso), 155.5
(s, C-2), 149.8 (s, C-6), 141.7 (s, C-5), 136.6 (s, o-C), 131.6 (s,
C-4), 131.0 (s, C-3), 126.5 (s, m-C), 122.6 (s, p-C), 49.7 (s,
NMR (in CD2Cl2, 298 K, J values in Hz): δ 10.23 (dd, J HH
)
2
4
3
4
3
4
6.2, J HH ) 1.1, H-6), 9.67 (dd, J HH ) 8.0, J HH ) 1.7, H-6′),
3
3
8.79 (d, J HH ) 5.8, H-3′), 8.16 (d, J HH ) 6.9, H-3), 8.02 (dd,
3J HH ) 7.7, J HH ) 1.7, H-5′), 7.96 (t, J HH ) 5.12, H-4), 7.89
4
3
(m, H-5), 7.65 (m, H-4′), 7.30 (m, o-H), 7.02 (t, 3J HH ) 6.9, m-H),
1
3
3
2
COMe), 27.1 (s, COMelig), 14.2 (Harris t, | J PC + J PC| ) 29.8,
7.87 (t, J HH ) 6.6, p-H), 2.59 (s, COMe), 1.05 (Harris t, | J PH
PMe3). Complex 3b: 1H NMR (in CD2Cl2, 298 K, J values in
+ J PH| ) 3.7, PMe3). 31P{1H} NMR: -3.3 (s, PMe3). 13C{1H}
4
Hz): δ 8.63 (d, 3J HH ) 4.6, H-6), 7.63 (m, H-4), 7.59 (d, 3J HH
)
NMR: 255.7 (s, COMe), 205.1 (s, CO), 196.6 (s, CO of the
3
3
1
7.6, H-3), 7.45 (t, J HH ) 6.8, H-5), 7.47 (m, o-H), 7.02 (t, J HH
) 7.3, m-H), 6.87 (t, J HH ) 8.6, p-H), 2.66 (t, J HH ) 3.4,
ligand), 164.8 (q, J BC ) 49.6, C-ipso), 155.7 (s, C-6), 152.5 (s,
3
5
C-2), 150.3 (s, C-6′), 149.8 (s, C-2′), 140.7 (s, C-3′), 139.1 (s,
C-3), 136.6 (s, o-C), 136.4 (s, C-5′), 131.5 (s, C-4), 129.9 (s, C-5),
128.0 (s, C-4′), 126.4 (s, m-C), 122.5 (s, p-C), 49.8 (s, COMe),
2
4
COMelig), 2.49 (s, COMe), 1.04 (Harris t, | J PH + J PH| ) 5.8,
PMe3). 31P{1H} NMR: -2.8 (s, PMe3). 13C{1H} NMR: 256.5 (br,
2
1
3
COMe), 208.0 (s, COMelig), 204.7 (t, J CP ) 14.3, CO), 165.8
(s, C-2), 164.7 (q, J BC ) 49.2, C-ipso), 153.6 (s, C-6), 141.3 (s,
14.3 (Harris t, | J PC + J PC| ) 29.8, PMe3)
1
C-4), 136.6 (s, o-C), 132.2 (s, C-3), 131.7 (s, C-5), 126.5 (s, m-C),
122.6 (s, p-C), 45.4 (s, COMe), 27.1 (s, COMelig), 14.3 (Harris
Ack n ow led gm en t. The authors wish to thank Dr.
Silvia Terenzi for the preliminary preparations of some
complexes. This work was supported by grants from the
Consiglio Nazionale delle Ricerche (CNR, Rome, Italy)
and the Ministero dell’Universita` e della Ricerca Sci-
entifica e Tecnologica (MURST, Rome, Italy).
1
3
t, | J PC + J PC| ) 29.9, PMe3).
P r ep a r a tion of tr a n s-[Ru (P Me3)2(CO)(COMe)(2-bzp y)]-
BP h 4 (4b). The procedure was the same as that for 2b and
3b (yield 68%). IR (CH2Cl2): νCO 1956 cm-1; νCOMe 1610 cm-1
.
3
1H NMR (in CD2Cl2, 294 K, J values in Hz): δ 10.23 (d, J HH
) 5.5, H-6), 8.18 (dd, 3J HH ) 7.7, 4J HH ) 1.1, H-3), 7.83 (t, 3J HH
Su p p or tin g In for m a tion Ava ila ble: Atomic coordinates
and equivalent isotropic displacement coefficients (Table S1),
anisotropic displacement coefficients (Table S2), H-atom co-
ordinates and isotropic displacement coefficients (Table S3),
and bond lengths and bond angles (Table S4) for 4b (8 pages).
Ordering information is given on any current masthead page.
3
) 7.0, H-4), 7.82 (dd J HH ) 5.3, 4J HH ) 1.7, H-5), 7.81 (d, 3J HH
) 7.2, H-4′), 7.68 (d, 3J HH ) 7.0, H-2′), 7.64 (t, 3J HH ) 7.3, H-3′),
3
3
7.31 (m, o-H), 6.99 (t, J HH ) 7.4, m-H), 6.85 (t, J HH ) 7.2,
p-H), 2.57 (s, COMe), 1.05 (Harris t, | J PH + 4J PH| ) 7.2, PMe3).
2
31P{1H} NMR: 17.4 (s, PMe3). 13C{1H} NMR: 255.5 (t, J CP
)
2
2
9.2, COMe), 204.6 (t, J CP ) 14.7, CO), 201.2 (s, COPh), 164.4
(q, J BC ) 49.2, C-ipso), 156.6 (s, C-2), 156.1 (s, C-6), 149.3 (s,
1
OM980460P