X-ray diffraction studies of group 9 transition-metal complexes containing an sp3 C-H activated functionalized triphenylphosphine

Article abstract of DOI:10.1021/om990563n

Treatment of the hemilabile tertiary phosphino amide o-Ph₂PC₆H₄CH₂N(Me)C(O)Et (DPPBA; 1) with the appropiate Rh(I) or Ir(I) precursor complex results in cyclometalation by oxidative addition of the benzylic C - H bond to the metal center. The solution structures of the two synthesized complexes [RhH(PPh₃)₂-(DPPBA)][PF₆] (2) and [IrH(1,5-COD)(DPPBA)][BF₄] (3) have been unambiguously identified by various NMR spectroscopic techniques. Also, single-crystal X-ray diffraction studies have been performed for 2 and 3. These are the first crystal structures obtained with DPPBA as a ligand, giving final confirmation of the capability of 1 to trischelate in platinum group metal complexes.

Full text of DOI:10.1021/om990563n

5412
Organometallics 1999, 18, 5412-5415
X-r a y Diffr a ction Stu d ies of Gr ou p 9 Tr a n sition -Meta l
Com p lexes Con ta in in g a n sp 3 C-H Activa ted
F u n ction a lized Tr ip h en ylp h osp h in e
Sven Sjo¨vall, Per H. Svensson, and Carlaxel Andersson*
Inorganic Chemistry 1, Centre for Chemistry and Chemical Engineering, Lund University,
P.O. Box 124, S-221 00 Lund, Sweden
Received J uly 20, 1999
Sch em e 1
Summary: Treatment of the hemilabile tertiary phos-
phino amide o-Ph2PC6H4CH2N(Me)C(O)Et (DPPBA; 1)
with the appropiate Rh(I) or Ir(I) precursor complex
results in cyclometalation by oxidative addition of the
benzylic C-H bond to the metal center. The solution
structures of the two synthesized complexes [RhH(PPh3)2-
(DPPBA)][PF6] (2) and [IrH(1,5-COD)(DPPBA)][BF4] (3)
have been unambiguously identified by various NMR
spectroscopic techniques. Also, single-crystal X-ray dif-
fraction studies have been performed for 2 and 3. These
are the first crystal structures obtained with DPPBA as
a ligand, giving final confirmation of the capability of
1 to trischelate in platinum group metal complexes.
In tr od u ction
Transition-metal complexes with tridentate PCP-type
ligands were first reported in the early 1970s1 and have
been extensively studied since.2 These structurally well-
defined complexes, and the related compounds with
NCN or SCS ligands,3 have proved to be excellent
catalytic precursors over a wide range encompassing
dehydrogenation,4 coupling,5 addition,6 insertion,7 and
asymmetric8 reactions. However, metal insertion into
an sp3 C-H bond, instead of a C-H aryl bond, would
result in a more electron-rich metal center, which may
alter the catalytic activity. A recent comparative study
by Ohff et al. showed that a Pd(II) PCP-type complex,
formed by palladium insertion into an sp3 C-H bond of
1,3-bis[(diisopropylphosphino)methyl]-2,4,6-trimethyl-
benzene, was indeed a remarkable active catalyst in the
Heck reaction.9 To develop new functionalized tertiary
phosphines capable of forming tridentate metallacycles
by intramolecular metal insertion into sp3 C-H bonds
could be of importance in catalysis.
We have recently published an article elucidating the
coordination chemistry of the ligand DPPBA (1)
(N-methyl-N-propionyl-2-(diphenylphosphino)benzyl-
amine) in different rhodium complexes.10 There were
strong indications that this potential PCO-type ligand
coordinates tridentately by oxidative addition of a
benzylic C-H bond to the rhodium center, given the
right conditions. In this paper we would like to give final
confirmation of this by presenting the first crystal
structures obtained with 1 as a ligand coordinating in
a PCO manner in platinum group metal complexes.
(1) Moulton, C. J .; Shaw, B. L. J . Chem Soc., Dalton Trans. 1975,
1020.
(2) For examples see: (a) Shaw, B. L. J . Organomet. Chem. 1980,
200, 307. (b) Rybtchinski, B.; Milstein, D. Angew. Chem., Int. Ed. Engl.
1999, 38, 870.
(3) Steenwinkel, P.; Gossage, R. A.; van Koten, G. Chem. Eur. J .
1998, 4, 759.
Resu lt a n d Discu ssion
Syn t h esis a n d Sp ect r oscop ic P r op er t ies. To
achieve oxidative insertion of a rhodium center into
ligand 1, it is necessary to generate a species having a
metal center with high electron density and vacant
coordination sites.10 Accordingly, complex 2 could only
be synthesized by treating the precursor [Rh(2,5-NBD)-
(PPh3)2][PF6] with ligand 1 under an atmosphere of
dihydrogen (Scheme 1) and thereby removing the π-ac-
cepting diene from the coordination sphere. The result-
ing complex was unambiguously characterized by vari-
(4) (a) Gupta, M.; Hagen, C.; Flesher, R. J .; Kaska, W. C.; J ensen,
C. M. Chem. Commun. 1996, 2083. (b) Gupta, M.; Kaska, W. C.;
J ensen, C. M. Chem. Commun. 1997, 461. (c) Gupta, M.; Kaska, W.
C.; J ensen, C. M. Chem. Commun. 1997, 2273. (d) Gupta, M.; Kaska,
W. C.; Cramer, R. E.; J ensen, C. M. J . Am. Chem. Soc. 1997, 119, 840.
(5) van Koten, G. Pure Appl. Chem. 1994, 66, 1455.
(6) (a) Grove, D. M.; Verschuuren, A. H. M.; van Koten, G.; van Beck,
J . A. M. J . Organomet. Chem. 1989, 372, C1. (b) Knapen, J . W. J .; van
der Made; A. W.; de Wilde, J . C.; van Leeuwen, P. W. N. M.; Wijkens,
P.; Grove, D. M.; van Koten, G. Nature 1994, 372, 659.
(7) (a) Canty, A. J .; van Koten, G. Acc. Chem. Res. 1995, 28, 406.
(b) Donkervoort, J . G.; Vicario, G. L.; J astrzebski, J . T. B. H.; Gossage,
R. A.; Cahiez, G.; van Koten, G. J . Organomet. Chem. 1998, 558, 61.
(8) (a) Gorla, F.; Togni, A.; Venanzi, L. M.; Albinati, A.; Lianza, F.
Organometallics 1994, 13, 267. (b) Longmire, J . M.; Zhang, X. Organo-
metallics 1998, 17, 4374.
(9) Ohff, M.; Ohff, A.; van der Boom, M. E.; Milstein, D. J . Am.
Chem. Soc. 1997, 119, 11687.
(10) Sjo¨vall, S.; Kloo, L.; Nikitidis, A.; Andersson, C. Organometallics
1998, 17, 579.
10.1021/om990563n CCC: $18.00 © 1999 American Chemical Society
Publication on Web 11/11/1999

Notes
Organometallics, Vol. 18, No. 25, 1999 5413
ous NMR spectroscopic techniques. The 31P{1H} NMR
spectrum of 2 exhibits an ABCX pattern; two doublet
of doublet of doublet resonances at 54.8 (1J RhP ) 114
2
Hz, J PP ) 383, 23 Hz) and 40.1 ppm (1J RhP ) 110 Hz,
2J PP ) 383, 23 Hz) and a doublet of triplets at 26.2 ppm
1
(1J RhP ) 87 Hz, 2J PP ) 23 Hz). In the H NMR spectrum
the Rh-H group gives rise to a doublet of quartets
2
positioned at -16.5 ppm (1J RhH ) 7.3 Hz, J PH ) 16.9
Hz), which collapses to a doublet in 1H{31P} NMR. In
addition, the remaining benzylic proton resonates at
4.30 ppm (3J PH ) 19.8 Hz). The benzylic carbon appears
in the 13C{1H} NMR as an unresolved multiplet at 73.1
ppm. Also, the IR spectrum reveals both a Rh-H band
(2117 cm-1) and a coordinating CdO stretching fre-
quency (1570 cm-1). X-ray crystallography of 2 has been
carried out, and all spectroscopic evidence suggests that
the solution and solid-state structures are the same.
As we will see, when using the last member of group
9 as the transition-metal center, it is not essential to
generate a complex exclusively with σ-donors to achieve
metallacyclic formation with 1 as a ligand (cf. complex
2). Complex 3 was obtained by treating a dichloro-
methane solution of the diene complex [Ir(1,5-COD)2]-
[BF4] with 1. The obtained set of NMR data strongly
suggest the configuration of 3 in solution to be as
depicted in Scheme 1. In the 31P{1H} NMR spectrum a
singlet at 33.2 ppm is observed. Metal insertion at the
F igu r e 1. Perspective view (ORTEP) of cation 2. Bond
distances (Å) and angles (deg) with estimated standard
deviations: Rh-P1 ) 2.317(2); Rh-P2 ) 2.411(1); Rh-P3
) 2.354(2); Rh-O ) 2.150(4); Rh-C5 ) 2.123(6); Rh-H1
) 1.46(6); P1-Rh-P2 ) 99.63(6); P1-Rh-P3 ) 160.46(5);
P1-Rh-C5 ) 80.04(17); P1-Rh-O ) 90.88(12); C5-
Rh-O ) 79.89(19).
benzylic group results in two doublets at 5.32 (3J PH
)
bond length between the sp3-hybridized carbon and the
rhodium atom (Rh-C5 ) 2.123(6) Å), as well as the Rh-
H1 (1.46(6) Å) bond distance, is in agreement with the
values observed in other metalated Rh(III) species.12
The cyclometalated trischelating DPPBA ligand is
displaying a fac arrangement around the rhodium atom,
resulting in two five-membered chelate rings. Both the
P1-Rh-C5 (80.04(17)°) and C5-Rh-O (79.89(19)°)
angles are acute due to ring strain, and the Rh-P1 and
Rh-O bonds are nearly perpendicular to each other
(P1-Rh-O angle is 90.88(12)°).
2.7 Hz) and -17.8 ppm (2J PH ) 11.7 Hz) exhibited in
the H NMR spectrum and a doublet at 61.6 ppm (2J PC
1
) 6.7 Hz) in the 13C{1H} NMR spectrum. HMQC NMR
spectroscopy verifies these assignments. Furthermore,
the positions of the Ir-H (2195 cm-1) and the CdO
(1581 cm-1) stretches in the IR spectrum also indicate
the hydride to be apical and coordination of the carbonyl
functionality. Final confirmation of a metallacyclic
structure in 3 has been obtained by X-ray crystal-
lography.
X-r a y Diffr a ction Stu d ies. The convincing spectro-
scopic evidence suggesting complex 2 to be the result of
an oxidative addition of a benzylic C-H bond to the
rhodium center has been supported by a single-crystal
X-ray analysis. Colorless blocks of 2 were obtained upon
crystallization by layering diethyl ether onto a chloro-
form solution. Four chloroform molecules are present
in the triclinic unit cell. A perspective view of the
molecular structure is shown in Figure 1, including
selected bond distances and angles.
The complex has a distorted-octahedral configuration
in which the rhodium center is surrounded in the
equatorial plane by the three phosphorus atoms and the
metalated carbon atom. The apical positions are oc-
cupied by the strongest trans director, the hydride
ligand, being located trans to the weakest one, the
carbonyl oxygen atom. The Rh-P1 and Rh-P3 bond
distances are of normal magnitude,11 and the signifi-
cantly longer Rh-P2 bond distance (2.411(1) Å) mani-
fests the strong trans influence exerted by the C5 atom.
Note the correlation between the rhodium-phosphorus
bond lengths and the positions of the individual phos-
phorus resonances in the 31P{1H} NMR spectrum. The
For the definite characterization of complex 3, a
single-crystal X-ray diffraction analysis was carried out.
Slow vapor diffusion of diethyl ether into a dichloro-
methane solution led to the deposition of 3 as colorless
blocks. The triclinic unit cell belongs to the space group
P1h. A view of the molecular structure is shown in Figure
2, including selected bond distances and angles.
The coordination geometry about the iridium center
can be rationalized as a distorted octahedron, where the
equatorial plane is constituted by the phosphorus and
nitrogen atoms and the midpoints of the η2:η2 coordinat-
ing diene. As for complex 2, the apical positions are
occupied by the hydride and the carbonyl oxygen atom.
The observed Ir-H1 bond distance (1.57(8) Å) is in good
agreement with those established for other hydrido-
iridium(III) complexes.13 The hydride, one alkene π-bond,
and the iridium center are coplanar, but clearly the
exclusive cis addition of the metal hydride to the diene
does not take place,14 a phenomenon seen in other
(12) (a) Sharp, R. P. Compr. Organomet. Chem. II 1995, 8, Chapter
2. (b) Liou, S.-Y.; Gozin, M.; Milstein, D. J . Am. Chem. Soc. 1995, 117,
9774. (c) Lesueur, W.; Solari, E.; Floriani, C.; Chiesa-Villa, A.; Rizzoli,
C. Inorg. Chem. 1997, 36, 3354.
(13) For examples see: (a) Milstein, D.; Calabrese, J . C.; Williams,
I. D. J . Am. Chem. Soc. 1986, 108, 6387. (b) Stoutland, P. O.; Bergman,
R. G. J . Am. Chem. Soc. 1988, 110, 5732. (c) Sjo¨vall, S.; J ohansson,
M.; Andersson, C. Organometallics 1999, 18, 2198.
(11) For examples see: (a) Orpen, A. G.; Brammer, L.; Allen, F. H.;
Kennard, O.; Watson, D. G.; Taylor, R. J . Chem. Soc., Dalton Trans.
1989, S1. (b) Dunne, B. J .; Morris, R. B.; Orpen, A. G. J . Chem. Soc.,
Dalton Trans. 1991, 653.
(14) J ames, B. R. Compr. Organomet. Chem. 1982, 8, 306.

5414 Organometallics, Vol. 18, No. 25, 1999
Notes
Exp er im en ta l Section
The general procedures and purification of solvents have
been previously described.10 Commercially available reagents
were purchased and used without further purification. The
phosphine DPPBA (1)17 and the complexes [Ir(1,5-COD)2]-
[BF4]18 and [Rh(2,5-NBD)(PPh3)2][PF6]19 were prepared ac-
cording to literature procedures.
1H, 31P, and 13C NMR spectra were recorded at 300, 121,
and 75 MHz, respectively, using a Varian Unity 300 MHz
spectrometer. HMQC (2D inverse 1H, 13C correlation) NMR
spectra were recorded at 500 MHz using a Bruker ARX 500
MHz spectrometer. All NMR measurements were performed
in CDCl3. Infrared spectra were recorded on a Bio-Rad FTS
6000 FT-IR spectrometer. Melting points were determined in
argon-sealed capillary tubes and are uncorrected. Elemental
analyses were performed by AB Mikro Kemi, Uppsala, Swe-
den.
Rea ction of [Rh (2,5-NBD)(P P h 3)2][P F 6] w ith 1. F or m a -
t ion of [R h H (P P h 3)2(DP P BA)][P F 6] (2). A red dichloro-
methane solution (10 mL) of DPPBA (1; 140 mg, 0.162 mmol)
and [Rh(2,5-NBD)(PPh3)2][PF6] (58.8 mg, 0.163 mmol) was
cooled to -10 °C. The argon atmosphere was replaced by
molecular hydrogen, and the solution was allowed to reach
room temperature. After 1 h the solution was yellow and once
again the atmosphere was replaced, this time from dihydrogen
to argon. Upon leaving the solution for half an hour, it turned
slightly brown. The solvent was concentrated under vacuum
to ca. 2 mL, and addition of diethyl ether yielded an off-white
precipitate. The suspension was filtered in air and washed
with diethyl ether (2 × 10 mL) and n-hexane (2 × 10 mL).
Isolated yield: 169 mg (92%). 31P{1H} NMR: δ 54.8 (ddd, 1J RhP
F igu r e 2. Perspective view (ORTEP) of cation 3. Bond
distances (Å) and angles (deg) with estimated standard
deviations: Ir-P ) 2.284(2); Ir-O ) 2.149(4); Ir-C5 )
2.082(6); Ir-C24 ) 2.276(7); Ir-C25 ) 2.285(7); Ir-C28
) 2.270(6); Ir-C29 ) 2.244(7); Ir-H1 ) 1.57(8); C24-C25
) 1.364(12); C28-C29 ) 1.375(10); P-Ir-C5 ) 82.2(2);
P-Ir-O ) 89.1(1); C5-Ir-O ) 80.3(2).
related complexes.15 The Ir-P bond distance (2.284(2)
Å) matches well the values reported for other iridium-
phosphine complexes11 and is very close to that estab-
lished for the related cyclometalated phosphino ester
complex [IrH(1,5-COD)(2-Ph2PC6H4CHOC(O)Et)][BF4].13c
Also, the Ir-O bond length (2.149(4) Å) is somewhat
shorter than in the aforementioned complex, probably
reflecting a slightly stronger donor strength for the
amide than for the ester group. In fact, the interaction
between the iridium and oxygen atoms is strong since
it is close to the sum of the covalent radii (2.02 Å). The
Ir-C5 bond distance (2.082(6) Å) falls within the range
reported for other sp3-cyclometalated hydridoiridi-
um(III) complexes.16 In contrast to complex 2 there is
just a slight difference in trans influence between the
C5 and the P donor atoms, reflected by the following
properties: (i) the Ir-C(olefin) bond distances for Ir-
C24 and Ir-C25 are 2.276(7) and 2.285(7) Å, respec-
tively, compared to the values for Ir-C28 (2.270(6) Å)
and Ir-C29 (2.244(7) Å); (ii) the respective bond dis-
tances between the sp2-carbon atoms in the diene ligand
are 1.364(12) Å for C24-C25 and 1.375(10) Å for C28-
C29. As for complex 2, the cyclometalated DPPBA
ligand is capping one triangular face of the octahedron
in which the P-Ir-C5 and C5-Ir-O angles are acute
(82.2(2)° and 80.3(2)°, respectively) and the Ir-P and
Ir-O bonds are nearly perpendicular to each other (P-
Ir-O angle is 89.1(1)°).
2
1
2
) 114 Hz, J PP ) 383, 23 Hz), 40.1 (ddd, J RhP ) 110 Hz, J PP
1
2
) 383, 23 Hz), 26.2 (dt, J RhP ) 87 Hz, J PP ) 23 Hz), -143.7
(sept, J PF ) 712 Hz). 1H NMR: δ 7.42-7.02 (m, 42H, Ar),
1
3
3
6.75 (bt, J HH ) 8.2 Hz, 1H, Ar), 5.96 (bt, J HH ) 9.4 Hz, 1H,
3
Ar), 4.30 (d, J PH ) 19.8 Hz, 1H, Ar-C(R)H-Rh), 1.91 (s, 3H,
3
N-CH3), 1.27-0.82 (m, 2H, -CH2-), 0.73 (bt, J HH ) 6.4 Hz,
1
2
3H, -CH3), -16.5 (dq, J RhH ) 7.3 Hz, J PH ) 16.9 Hz, 1H,
Rh-H)). 13C{1H} NMR: δ 179 (s, -C(O)-), 152-128 (md, Ar),
73.1 (m, Ar-C(R)H-Rh), 34.1 (s, N-CH3), 26.7 (s, -CH2-),
7.92 (s, -CH3), (assignment of H and 13C{1H} NMR signals
1
were confirmed by 1H{31P} and HMQC NMR experiments). IR
(KBr): 2117 cm-1 (w, Rh-H), 1570 cm-1 (s, CdO); mp 165-
170 °C dec. Anal. Calcd for C59H54F6NOP4Rh: C, 62.5; H, 4.8;
P, 10.9. Found: C, 62.3; H, 5.1; P, 10.6.
Rea ction of [Ir (1,5-COD)2][BF 4] w ith 1. F or m a tion of
[Ir H(1,5-COD)(DP P BA)][BF 4] (3). When [Ir(1,5-COD)2][BF4]
(102 mg, 0.206 mmol) and DPPBA (1; 74.4 mg, 0.206 mmol)
were mixed in dichloromethane (10 mL), the solution gradually
changed color from dark red to light yellow within minutes.
After 30 min an off-white powder was isolated by evaporation
of the solvent, which was sequentially washed in air with
diethyl ether (3 × 10 mL) and n-hexane (3 × 10 mL). Isolated
yield: 125 mg (81%). 31P{1H} NMR: δ 33.2 (s). 1H NMR: δ
3
7.75-6.94 (m, 14H, Ar), 5.70 (m, 1H, COD), 5.32 (d, J PH
)
In summary, these crystallographic investigations
have clearly shown that the triphenyl phosphine deriva-
tive DPPBA (1) does oxidatively add one of its benzylic
C-H bonds to platinum group metals, given the right
conditions. In doing so it adopts a fac configuration, and
the resulting hydride ultimately resides in an apical
position trans to the coordinated carbonyl functionality.
2.7 Hz, 1H, Ar-C(R)H-Ir), 5.01 (m, 1H, COD), 4.55 (m, 1H,
COD), 4.43 (m, 1H, COD), 2.89 (s, 3H, N-CH3), 2.56-2.30 (m,
8H, COD), 2.16 (m, 1H, -CH2-), 1.48 (m, 1H, -CH2-), 0.60
3
2
(t, J HH ) 7.3 Hz, 3H, -CH3), -17.8 (d, J PH ) 11.7 Hz, 1H,
Ir-H); 13C{1H} NMR: δ 180 (s, -C(CO)-), 156-125 (md, Ar),
2
97.1 (d, J PC ) 14.8 Hz, COD), 96.6 (m, COD), 90.4 (s, COD),
2
88.8 (s, COD), 61.6 (d, J PC ) 6.7 Hz, Ar-C(R)H-Ir), 35.5 (s,
COD), 33.1 (s, N-CH3), 32.9 (s, COD), 29.2 (s, COD), 27.8 (s,
1
COD), 26.7 (s, -CH2-), 8.1 (s, -CH3) (assignment of H and
(15) For examples see: (a) Fernandez, M. J .; Esteruelas, M. A.; Oro,
L. A.; Apreda, M. C.; Foces-Foces, C.; Cano, F. H. Organometallics
1987, 6, 1751. (b) Bianchini, C.; Farnetti, E.; Graziani, M.; Nardin,
G.; Vacca, A.; Zanobini, F. J . Am. Chem. Soc. 1990, 112, 9190. (c)
Esteruelas, M. A., Olivan, M.; Oro, L. A.; Schulz, M.; Sola, E.; Werner,
H. Organometallics 1992, 11, 3659.
1
13C{1H} NMR signals were confirmed by H{31P} and HMQC
(17) Nikitidis, A.; Andersson, C. Phosphorous, Sulfur Silicon Relat.
Elem. 1993, 78, 141.
(18) Schenck, T. G.; Downes, J . M.; Milne, C. R. C.; Mackenzie, P.
B.; Boucher, H.; Whelan, J .; Bosnich, B. Inorg. Chem. 1985, 24, 2334.
(19) Schrock, R. R.; Osborn, J . A. J . Am. Chem. Soc. 1976, 98, 2143.
(16) (a) Clark, G. R.; Greene, T. R.; Roper, W. R. J . Organomet.
Chem. 1985, C25, 293. (b) Reference 13c.

Notes
Organometallics, Vol. 18, No. 25, 1999 5415
Ta ble 1. Cr ysta llogr a p h ic Da ta for Com p lexes 2 a n d 3
formula
fw
C59H54F6NOP4Rh (2) + 2CHCl3
C31H36BF4IrNOP (3)
748.59
1372.56
0.26 × 0.18 × 0.11
triclinic
P1h (No. 2)
12.4288(9)
15.4089(11)
16.3996(12)
88.746(2)
87.840(2)
79.276(2)
3083.4(4)
2
cryst size, mm3
cryst syst
space group
a, Å
0.21 × 0.16 × 0.09
triclinic
P1h (No. 2)
10.3296(5)
11.4514(6)
13.3332(8)
79.426(1)
77.561(1)
77.746(1)
1489.3(1)
2
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
d
calcd, g cm-3
1.478
1.669
diffractometer
radiation (graphite monochr)
temp, K
smart CCD system
Mo KR (0.710 73 Å)
293(2)
0.700
ω
50
smart CCD system
Mo KR (0.710 73 Å)
293(2)
4.587
ω
55
µ, mm-1
scan method
2θ(max), deg
abs corr20
ω-scan/multiscan
0.831
ω-scan/multiscan
0.372
Tmin
Tmax
Rint
0.926
0.0576
0.662
0.0493
23
total no. of rflns
no. of unique rflns
no. of obsd rflns (2σ(I))
no. of params refined
R24
18646
10809
5871
724
0.0606
0.1262
10846
6787
5552
379
0.0580
0.1110
25
Rw
rfln:param ratio
14.93
0.848
17.91
1.670
resid electron density, e Å-3
NMR experiments). IR (KBr): 2195 cm-1 (m, Ir-H), 1581 cm-1
(s, CdO); mp 188-193 °C dec. Anal. Calcd for C31H36BF4-
IrNOP: C, 49.7; H, 4.8; P, 4.1. Found: C, 49.5; H, 4.9; P, 4.0.
X-r a y Str u ctu r a l An a lyses of Com p lexes 2 a n d 3. Single
crystals were grown from chloroform/diethyl ether (2) and
dichloromethane/diethyl ether (3) solutions at room temper-
ature. The crystal data, data collection, and refinement details
are provided in Table 1. Intensity data were collected at 293
K with a Smart CCD system using ω scans and a rotating
anode with Mo KR radiation (λ ) 0.710 73 Å). All reflections
were corrected for Lorentz and polarization effects as well as
absorption.20 No significant changes in intensities were noticed
throughout the data collections.
atoms were constrained to parent sites, using a riding model.
The coordinated hydrides in 2 and 3, respectively, were located
from the difference Fourier map after anisotropic refinement,
and then the hydrides were isotropically refined. No high
electron density residues were found in the structures.
Ack n ow led gm en t. Financial support by the TFR
(The Swedish Research Council for Technological Sci-
ences) and the NFR (The Swedish Natural Science
Research Council) is gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Tables of structure
refinement, atomic coordinates, bond lengths and angles,
anisotropic displacement parameters, and hydrogen coordi-
nates for complexes 2 and 3. Figures of complexes 2 and 3
showing complete atomic numbering. This material is available
free of charge via the Internet at http://pubs.acs.org.
The structures were solved by Patterson methods using
SHELXS-97,21 while the structure refinements were performed
on F2 using SHELXL-97.22 All non-H atoms were refined with
anisotropic displacement parameters, while the hydrogen
(20) Sheldrick; G. M. SADABS: Program for Absorption Correction;
University of Go¨ttingen, Go¨ttingen, Germany, 1996.
OM990563N
(21) Sheldrick; G. M. SHELXS-97: Structure Solution Program;
University of Go¨ttingen, Go¨ttingen, Germany, 1990.
(22) Sheldrick; G. M. SHELXL-97: Structure Refinement Program;
University of Go¨ttingen, Go¨ttingen, Germany, 1997.
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2
(23) Rint ) ∑|Fo - Fo2(mean)|/∑|Fo |.
(24) R ) ∑|Fo| - |Fc||/∑|Fo|.
(25) Rw ) [∑(w(Fo - Fc2)2)/∑(w(Fo2)2)].
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