Half-sandwich aminorhenium complexes: preparation and regioselective N-versus re-alkylations

Article abstract of DOI:10.1021/om960980p

The aminorhenium complex (CO)₂ReNH(CH₃)CH₂CH₂(η ⁵-C₅H₄) (3), in which the ligating amino group is connected to the cyclopentadienyl ligand, was prepared by irradiation of (η⁵-C₅H₄CH₂CH ₂NHCH₃)Re(CO)₃ (2) in THF. Alkylation of the corresponding anion [(CO)₂ReN(CH₃)CH₂CH₂(η ⁵-C₅H₄)]^-Li⁺ (4) as well as the neutral aminorhenium complex 3 with a variety of electrophiles has been studied. The anion 4 reacted with electrophiles, such as CH₃I, CH₂=CHCH₂Br, C₆H₅CH₂Br, and HC≡CCH₂Br, at the nitrogen center to provide (CO)₂ReNR(CH₃)CH₂CH₂(η ⁵-C₅H₄) (5a-d). However, 4 reacted with electrophiles having a carbonyl group or a nitrile group next to the electrophilic carbon, such as BrCH₂-CO₂CH₃, BrCH₂CO₂C₂H₅, and BrCH₂CN, to give rhenium alkylation compounds [(CO)₂(R)-ReNH(CH₃)CH₂CH₂(η ⁵-C₅H₄)]⁺Br^- (7e-g) after protonation. The neutral aminorhenium complex 3 reacted with the electrophiles mentioned above to provide exclusive Re-alkylation compounds 7a-g. The structure of the tetraphenylborate salt of 7c, [(CO)₂(C₆H₅-CH₂)ReNH(CH ₃)CH₂CH₂(η⁵-C₅H ₄)]⁺BPh₄^- (8), has been determined by X-ray diffraction.

Full text of DOI:10.1021/om960980p

1218
Organometallics 1997, 16, 1218-1223
Ha lf-Sa n d w ich Am in or h en iu m Com p lexes: P r ep a r a tion
a n d Regioselective N-ver su s Re-Alk yla tion s
Tein-Fu Wang,* Ching-Yih Lai, Chong-Chen Hwu, and Yuh-Sheng Wen
Institute of Chemistry, Academia Sinica, Taipei, Taiwan
Received November 19, 1996X
The aminorhenium complex (CO)2ReNH(CH3)CH2CH2(η5-C5H4) (3), in which the ligating
amino group is connected to the cyclopentadienyl ligand, was prepared by irradiation of
(η5-C5H4CH2CH2NHCH3)Re(CO)3 (2) in THF. Alkylation of the corresponding anion
[(CO)2ReN(CH3)CH2CH2(η5-C5H4)]-Li+ (4) as well as the neutral aminorhenium complex 3
with a variety of electrophiles has been studied. The anion 4 reacted with electrophiles,
such as CH3I, CH2dCHCH2Br, C6H5CH2Br, and HCtCCH2Br, at the nitrogen center to
provide (CO)2ReNR(CH3)CH2CH2(η5-C5H4) (5a -d ). However, 4 reacted with electrophiles
having a carbonyl group or a nitrile group next to the electrophilic carbon, such as BrCH2-
CO2CH3, BrCH2CO2C2H5, and BrCH2CN, to give rhenium alkylation compounds [(CO)2(R)-
ReNH(CH3)CH2CH2(η5-C5H4)]+Br- (7e-g) after protonation. The neutral aminorhenium
complex 3 reacted with the electrophiles mentioned above to provide exclusive Re-alkylation
compounds 7a -g. The structure of the tetraphenylborate salt of 7c, [(CO)2(C6H5-
CH2)ReNH(CH3)CH2CH2(η5-C5H4)]+BPh4 (8), has been determined by X-ray diffraction.
-
Sch em e 1
In tr od u ction
Transition-metal complexes with an amino group
tethered to the cyclopentadienyl ligand have attracted
attention recently.1 Most of the investigations have
concentrated on the early-transition-metal compounds
for application as metallocene catalysts in olefin polym-
erization.2 There has not been much study on the
middle-3 and late-transition-metal4 compounds. Strong
σ donation of the amino ligand to the low-valent
transition metals may make the metal center electron-
rich, thereby enhancing the ability of the metal to
undergo nucleophilic reactions. This property is quite
interesting. Therefore, we wish to explore some of their
chemistry. Here, we report our results on the synthesis
and alkylation reactions of aminorhenium complexes.
of the neutral aminorhenium complex 3 gives exclusive
Re selectivity. The details are reported as follows.
Resu lts a n d Discu ssion
A. Syn th esis of Am in or h en iu m Com p lex 3. Ad-
dition of an excess of NaCp to ClCH2CH2NHCH3‚HCl
in THF provides a useful route to the substituted-
cyclopentadienyl compound C5H5CH2CH2NHCH3 (1),
which was obtained as a 1:1 mixture of the double-bond
isomers 1a and 1b.2c,3c Subsequent deprotonation with
n-BuLi gave a homogeneous cyclopentadienyl anion.
Reaction of the anion with Re(CO)5Br in refluxing THF
provided the half-sandwich rhenium tricarbonyl 2 (see
Scheme 1) in 82% yield as a pale yellow oil after column
chromatography and vacuum distillation. When stored
in a freezer, 2 became a waxy solid. The terminal
carbonyl stretchings of 2 appeared at 2021 and 1926
cm-1 as a strong and a broad strong bands, respectively,
in the infrared spectra, similar to those for the unsub-
stituted CpRe(CO)3. The methylamino group appeared
at δ 2.44, as is usual for amines, in the 1H NMR spectra.
Irradiation of a THF solution of 2 at 0 °C gave 3 as a
yellow powder in 64% yield. Presumably, carbon mon-
oxide was extruded upon irradiation followed by in-
tramolecular amino group coordination; alternatively,
Deprotonation of an aminorhenium complex such as
3 provides the anion 4. Nucleophilic reaction of 4 with
an electrophile may occur at either rhenium or nitrogen.
The behavior resembles the C- versus O-alkylation of
an enolate anion.5 The site of alkylation depends on
the nature of the alkylating agent. However, reaction
X Abstract published in Advance ACS Abstracts, February 15, 1997.
(1) For a brief review on functionalized cyclopentadienyl ligands,
see: Okuda, J . Comments Inorg. Chem. 1994, 16, 185.
(2) (a) Shapiro, P. J .; Bunel, E.; Schaefer, W. P.; Bercaw, J . E.
Organometallics 1990, 9, 867. (b) Shapiro, P. J .; Cotter, W. D.; Schaefer,
W. P.; Labinger, J . A.; Bercaw, J . E. J . Am. Chem. Soc. 1994, 116,
4623. (c) Hughes, A. K.; Meetsma, A.; Teuben, J . H. Organometallics
1993, 12, 1936. (d) Okuda, J .; Schattenmann, F. J .; Wocadlo, S.; Massa,
W. Organometallics 1995, 14, 789. (e) Flores, J . C.; Chien, J . C. W.;
Rousch, M. D. Organometallics 1994, 13, 4140, (f) J utzi, P.; Kleimeier,
J . J . Organomet. Chem. 1995, 486, 287. (g) Herrmann, W. A.;
Morawietz, M. J . A.; Priermeier, T.; Mashima, K. J . Organomet. Chem.
1995, 486, 291. (h) Herrmann, W. A.; Anwander, R.; Munck, F. C.;
Scherer, W. Chem. Ber. 1993, 126, 331. (i) van der Hende, J . R.;
Hitchcock, P. B.; Lappert, M. F.; Nile, T. A. J . Organomet. Chem. 1994,
472, 79.
(3) (a) Wang, T. F.; Lee, T. Y.; Wen, Y. S.; Liu, L. K. J . Organomet.
Chem. 1991, 403, 353. (b) Wang, T. F.; Wen, Y. S. J . Organomet. Chem.
1992, 439, 155. (c) Wang, T. F.; Lee, T. Y.; Chou, J . W.; Ong, C. W. J .
Organomet. Chem. 1992, 423, 31.
(4) (a) J utzi, P.; Kristen, M. O.; Dahlhaus, J .; Neumann, B.;
Stammler, H. G. Organometallics 1993, 12, 2980. (b) J utzi, P.;
Dahlhaus, J .; Kristen, M. O. J . Organomet. Chem. 1993, 450, C1.
(5) Carey, F. A.; Sundberg, R. J . Advanced Organic Chemistry, Part
B: Reactions and Synthesis, 3rd ed.; Plenum Press: New York, 1990;
pp 23-27.
S0276-7333(96)00980-6 CCC: $14.00 © 1997 American Chemical Society

Half-Sandwich Aminorhenium Complexes
Organometallics, Vol. 16, No. 6, 1997 1219
Sch em e 2
When the anion 4 was allowed to react with electro-
philes having a carbonyl or a nitrile group next to the
electrophilic carbon, such as BrCH2CO2CH3, BrCH2-
CO2C2H5, and BrCH2CN, alkylation occurred exclu-
sively at rhenium to give 6e-g, respectively. Because
they are very sensitive to moisture, 6e-g are protonated
upon exposure to moisture. Therefore, a small amount
of water was added after alkylation to provide cationic
7e-g (see Scheme 2), respectively, in 62-98% yield. The
neutral amido intermediates 6e-g could be observed
in the infrared spectra, which displayed low terminal
carbonyl stretchings at 1896 and 1824 cm-1
. The
carbonyl stretchings of 7e-g appeared at much higher
frequencies, around 2052 ((3) and 1980 ((5) cm-1. In
1
the H NMR spectra, all four Cp protons of compounds
THF might fill the vacant site first6 followed by pendant
amino group substitution to give 3. The terminal
carbonyl stretchings of 3 appeared at 1893 and 1816
cm-1, much lower frequencies than those for CpRe-
(CO)2L compounds (L ) THF,6 N2,7 carbene,8 alkyne,9
and thiophene10 ). This indicates that the Re to CO π*
back-bonding for the aminorhenium complex 3 is much
stronger than that of the other complexes with ligands
other than the amino group. The amino group ligation
is further suggested by the downfield shift (0.71 ppm)
of the N-methyl resonance in the 1H NMR spectrum.
Due to vicinal coupling with the N-H proton, the
N-methyl appeared at δ 3.15 as a doublet (J ) 6 Hz).
The N-H proton appeared at δ 4.46 as a broad signal
and remained unchanged after shaking with D2O.
Yellow powders of 3 could be stored under air in a
refrigerator for several months without noticeable de-
composition. In solution, however, minor decomposition
was observed after 24 h at room temperature in air.
7e-g split into four different resonances, and one of the
resonances appeared below δ 7.00. Due to the vicinal
coupling with the N-H proton, the N-methyl group
appeared at δ 2.93 ((0.02) as a doublet (J ) 5.7 Hz).
However, unlike 3, the signal of the N-H proton (δ
9.49-9.04) disappeared upon shaking with D2O.
The effect of alkylating agent on the site selectivity
can be rationalized by use of the hard-soft acid-base
principle.12 The alkylating agents CH3I, CH2dCHCH2-
Br, C6H5CH2Br, and HCtCCH2Br favor the N-alkyla-
tion complex 5, while the “softer” alkylating agents
BrCH2CO2CH3, BrCH2CO2C2H5, and BrCH2CN choose
the “softer” rhenium as the reaction site to provide
exclusively the Re-alkylation complex 7. Cationic com-
plexes 7e-g could also be obtained by direct reaction
of 3 with the corresponding alkylating agents and will
be discussed in the following section.
C. Rea ction of th e Neu tr a l Am in or h en iu m Com -
p lex 3 w ith Electr op h iles: Exclu sive Re-Alk yla -
tion s. As described previously, the ligated amino group
could be making the rhenium center much more electron
rich, thereby enhancing the ability of the metal to react
with electrophiles. Indeed, the neutral aminorhenium
complex 3 is reactive enough toward electrophiles. For
example, 3 reacted with CH3I without addition of a
solvent gave exclusively the Re-alkylation compound 7a
in 97% yield. The addition product could be easily
characterized by the terminal CO stretchings. High CO
stretching frequencies appearing at 2040 and 1971 cm-1
for the reaction product suggest that the cationic Re-
alkylation compound 7a was obtained instead of the
neutral N-alkylation compound 5a . Similarly, reaction
of 3 with electrophiles such as CH2dCHCH2Br, C6H5-
CH2Br, HCtCCH2Br, BrCH2CO2CH3, BrCH2CO2C2H5,
and BrCH2CN, also provided exclusive Re-alkylation
compounds 7b-g in good yields (74 - 98%). None of
the N-alkylation compounds were observed. Because
the N-H is tightly bonded in complex 3, the nitrogen
is now fully substituted and has no room for accepting
an electrophile. This may be the rationale for the
observation of exclusive Re selectivity. A total of three
isomers, one trans and two cis, is possible for the Re-
alkylation reactions. However, only one isomer was
obtained. The rhenium tricarbonyl complex CpRe(CO)3
does not show similar reactivity. When it was treated
with the reagents mentioned above, only CpRe(CO)3 was
recovered.
B. Rea ction of th e An ion 4: Re- ver su s N-
Alk yla tion s. Although the N-H proton of 3 does not
exchange with D2O, it could be removed by n-BuLi to
give the anion 4, which showed characteristic low CO
stretching frequencies at 1836 and 1708 cm-1. Treat-
ment of 4 with CH3I gave the N,N-dimethyl complex
5a (see Scheme 2) in 72% yield. Having a plane of
symmetry, 5a showed quite simple 1H and 13C NMR
spectra. 5a has been obtained previously by irradiation
of the dimethylamino compound [η5-C5H4CH2CH2N-
(CH3)2]Re(CO)3 in THF.11 Reaction of the anion 4 with
other electrophiles, such as CH2dCHCH2Br, C6H5CH2-
Br, and HCtCCH2Br, also provided exclusive N-alky-
lation compounds (5b-d ) in comparable yields (67-
78%). The spectroscopic properties (IR, 1H and 13C
NMR) of 5b-d are not much different from those of 3.
The terminal carbonyl stretchings were evident around
1
1898 ((4) cm-1 and 1822 ((5) cm-1. In the H NMR
spectra, cyclopentadienyl protons appeared between δ
5.27 and 4.85 for compounds 5a -d .
(6) Barrientos-Penna, C. F.; Einstein, F. W. B.; J ones, T.; Sutton,
D. Inorg. Chem. 1982, 21, 2578.
(7) (a) Einstein, F. W. B.; Klahn-Oliva, A. H.; Sutton, D.; Tyers, K.
G. Organometallics 1986, 5, 53. (b) Sellmann, D. J . Organomet. Chem.
1972, 36, C27.
(8) (a) Casey, C. P.; Vosejpka, P. C.; Askham, F. R. J . Am. Chem.
Soc. 1990, 112, 3713. (b) Casey, C. P.; Czerwinki, C. J .; Hayashi, R.
K. J . Am. Chem. Soc. 1995, 117, 4189.
(9) (a) Einstein, F. W. B.; Tyers, K. G.; Sutton, D. Organometallics
1985, 4, 489. (b) Casey, C. P.; Yi, C. S. J . Am. Chem. Soc. 1992, 114,
6597.
(12) (a) Pearson, R. G. J . Am. Chem. Soc. 1963, 85, 3533. (b) Pearson,
R. G. J . Chem. Educ. 1968, 45, 581. (c) Pearson, R. G. J . Chem. Educ.
1968, 45, 643. (d) Pearson, R. G.; Songstad, J . J . Am. Chem. Soc. 1967,
39, 1827. (e) Ho, T. L. Tetrahedron 1985, 41, 3.
(10) Choi, M. G.; Angelici, R. J . J . Am. Chem. Soc. 1989, 111, 8753.
(11) Wang, T. F.; J uang, J . P.; Lin, K. J . Bull. Inst. Chem., Acad.
Sin. 1995, 42, 41.

1220 Organometallics, Vol. 16, No. 6, 1997
Wang et al.
cells with CaF2 windows. Melting points were determined by
using a Yanaco Model MP micro melting point apparatus and
were uncorrected. 1H NMR (200 or 300 MHz) and 13C NMR
(50 or 75 MHz) were obtained with Bruker AC-200 FT and
AC-300 FT spectrophotometers. For the assignment of 1H and
13C NMR data, the carbon bound to the nitrogen was desig-
nated as C1 and the hydrogens on C1 were designated as H1a
and H1b
. The next carbon was designated as C2, and the
hydrogens on C2 were designated as H2a and H2b. All chemical
shifts are reported in parts per million (ppm) relative to Me4-
Si. Elemental analyses were obtained on a Perkin-Elmer 2400
CHN elemental analyzer. Mass spectra were recorded on a
VG 70-250S mass spectrophotometer.
P r ep a r a tion of C5H5CH2CH2NHCH3 (1). A THF solution
of sodium cyclopentadienide (2 M, 190 mL, 0.38 mol) was
added to a stirred suspension of 2-(methylamino)ethyl chloride
hydrochloride (19.5 g, 0.15 mol) in THF (100 mL) and HMPA
(45 mL) at 0 °C over 20 min. The resulting mixture was
heated under reflux for 4 h. The resulting brown solution was
concentrated under water aspirator pressure. To the residue
was added water (500 mL), which was then extracted twice
with pentane (800 mL). The pentane layer was washed once
with water and then concentrated under water aspirator
pressure. The residue was then distilled (Kugelrohr), using a
dry ice cooling device, at 0.5 Torr and 40 °C. Colorless
distillates were collected to give 10.3 g of 1 (55% yield) as a
1:1 mixture of double-bond isomers. 1H NMR (CDCl3, 200
MHz): δ 6.45-6.07 (3H, m), 2.97-2.87 (2H, m), 2.82-2.73 (2H,
m), 2.64-2.57 (2H, m), 2.44 (3H, s).
-
F igu r e 1. ORTEP drawing of 8. BPh4 is omitted for
simplicity.
Treatment of 7c with sodium tetraphenylborate in
methanol provided the anion-exchanged compound 8.
The structure of 8 was determined unambiguously by
an X-ray diffraction study. Crystals of 8 were obtained
by slow diffusion of a CH2Cl2 solution of 8 into hexane.
Figure 1 shows that the benzyl group is trans to the
amino group with an angle of 144.6° (N-Re-C(9)). The
trans terminal CO groups have an angle of 103.2°
(C(16)-Re-C(17)), much smaller than that of N-Re-
C(9). These angles are close to the 138.9° value for the
angle methyl carbon-Re-acyl carbon and 101.2° for the
angle CO carbon-Re-CO′ carbon seen in the unteth-
ered four-legged piano-stool complex trans-CpRe(CO)2-
(COCH3)(CH3).13 The alkyl tether of 8 is bent down 6.7°
from the cyclopentadienyl ring toward rhenium (C(2)-
C(3)-Cp(centroid) ) 173.3°). This angle is smaller than
that of the tethered methoxycarbene complex (CO)2RedC-
(OCH3)CH2CH2(η5-C5H4),8b in which the alkyl tether is
bent down 9°. This may suggest that the strain
introduced by tethering a ligand to the cyclopentadienyl
ligand is smaller for a tethered four-legged piano-stool
complex, such as 8, than that of the tethered three-
legged piano stool complex, such as (CO)2RedC(OCH3)-
CH2CH2(η5-C5H4).
The cyclopentadiene species 1 (10.3 g, 83.6 mmol) was
dissolved in THF (104 mL). The solution was cooled in an ice-
water bath. A hexane solution of n-BuLi (1.6 M, 53 mL) was
then added over a period of 40 min. The resulting suspension
was 0.5 M (C5H4CH2CH2NHCH3)-Li+ and was ready for the
next reaction.
P r ep a r a tion of (η5-C5H4CH2CH2NHCH3)Re(CO)3 (2). A
suspension of (C5H4CH2CH2NHCH3)-Li+ in THF (0.5 M, 45
mL) was added to a stirred suspension of Re(CO)5Br (7.98 g,
19.65 mmol) in THF (100 mL) at room temperature. The
resulting orange solution was then heated under reflux for 20
h. The resulting brown solution was concentrated. The
residue was then chromatographed on neutral aluminum oxide
(activity V). The nonpolar fraction, possibly rhenium carbonyl,
was removed by using 5% ethyl acetate in hexanes. The
desired yellow band was collected by eluting with 100% ethyl
acetate. The yellow liquid that remained after solvents were
removed was distilled (Kugelrohr) at 0.5 Torr. A fraction
boiling at 130-140 °C was collected to give 6.326 g of 2 (82%
yield) as a pale yellow liquid at room temperature: mp 10.5
Con clu sion
We have demonstrated that a stable aminorhenium
complex could easily be prepared when the amino group
was tethered to the cyclopentadienyl ligand. The amino
ligand is an important element for promoting the
rhenium complex reactivity toward carbon electrophiles.
Alkylation of the neutral aminorhenium complex 3 gives
exclusive Re selectivities. The resulting cationic com-
plex 7 provides, further opportunity for studying the
reactivity of half-sandwich rhenium complexes, such as
ligand exchanges, electrophilic reactions, and others.
Alkylation of the anionic 4 with electrophiles provides
either Re- or N-alkylation complexes. The regioselec-
tivity is dependent on the nature of the electrophiles
and can be explained by use of the hard-soft acid-base
principle.12
°C. IR (CH2Cl2): 2021 (s), 1926 (br s) cm-1
.
1H NMR (CDCl3,
300 MHz): δ 5.30 (2H, t, J ) 2.0 Hz, Cp H), 5.24 (2H, t, J )
2.0 Hz, Cp H), 2.72 (2H, t, J ) 6.8 Hz), 2.57 (2H, t, J ) 6.8
Hz), 2.44 (3H, s). 13C NMR (CDCl3, 75 MHz): δ 194.2 (CO ×
3), 108.5 (C, Cp), 83.6 (CH × 2, Cp), 83.4 (CH × 2, Cp), 53.5
(CH2), 36.2 (CH3), 28.4 (CH2). Anal. Calcd for C11H12NO3Re:
C, 33.67; H, 3.08; N, 3.57. Found: C, 33.42; H, 3.35; N, 3.82.
P r ep a r a tion of (CO)2ReNH(CH3)CH2CH2(η5-C5H4) (3).
Complex 2 (6.326 g, 16.12 mmol) was placed in a cylindrical
borosilicate reaction vessel. THF (500 mL) was added. The
vessel containing the pale yellow solution was evacuated and
flushed with argon. Argon was then kept flowing during the
course of the reaction. The reaction vessel was immersed in
an ice-water bath. An irradiation source (Hanovia 450 W
medium-pressure Hg lamp) with a quartz filter was placed in
the middle of the reaction vessel. The reaction was monitored
by examining the carbonyl absorption in the infrared spectra.
After 2 h, about 30% of 2 remained unreacted. Prolonged
irradiation resulted in formation of side products. Therefore,
the reaction was terminated at this point and the resulting
yellow-brown solution was concentrated. The residue was then
flash-chromatographed on silica gel, with 50% ethyl acetate
in hexanes as eluent followed by 100% ethyl acetate. The first
Exp er im en ta l Section
Reactions that required anhydrous conditions were per-
formed under an argon atmosphere by means of Schlenk-tube
techniques. Infrared solution spectra were recorded on a
Perkin-Elmer 882 infrared spectrophotometer using 0.1 mm
(13) Goldberg, K. I.; Bergman, R. G. J . Am. Chem. Soc. 1989, 111,
1285.

Half-Sandwich Aminorhenium Complexes
Organometallics, Vol. 16, No. 6, 1997 1221
yellow band was collected and concentrated to give 3.78 g of 3
3.34 (3H, s), 2.49 (1H, t, J ) 2.5 Hz, -CtCH), 2.25-2.20 (2H,
m, H2’s). 13C NMR (CDCl3, 75 MHz): δ 204.8 (CO), 204.7 (CO),
119.7 (C, Cp), 80.5 (CH, Cp), 79.7 (CH, Cp), 77.3 (C, -Ct),
76.3 (CH, tCH), 76.0 (CH2, C1), 74.9 (CH2, Cp), 74.5 (CH, Cp),
62.8 (CH2, Re-CH2), 59.3 (CH3), 24.8 (CH2, C2). Mass spec-
trum (FAB, 187Re; m/ e (relative intensity (%)): 403 (80, M+),
375 (100, M+ - CO), 347 (38, M+ - 2CO). Anal. Calcd for
(64% yield) as a yellow powder: mp 110 °C (dec). IR (CH2-
Cl2): 1893 (s), 1816 (s) cm-1 1H NMR (CDCl3, 300 MHz): δ
.
5.28-5.26 (1H, m, Cp H), 5.23-5.21 (1H, m, Cp H), 5.05-5.03
(1H, m, Cp H), 4.88-4.86 (1H, m, Cp H), 4.46 (1H, br, -NH),
3.69-3.61 (1H, m), 3.15 (3H, d, J ) 6.0 Hz), 3.19-3.07 (1H,
m), 2.15 (1H, dt, J ) 14.4, 4.7 Hz), 1.98 (1H, ddd, J ) 14.4,
10.4, 5.3 Hz). 13C NMR (CDCl3, 75 MHz): δ 205.3 (CO), 205.1
(CO), 121.4 (C, Cp), 81.2 (CH, Cp), 78.0 (CH, Cp), 76.6 (CH,
Cp), 74.0 (CH, Cp), 72.8 (CH2), 52.4 (CH3), 26.0 (CH2). Mass
spectrum (FAB, 187Re; m/ e (relative intensity (%)): 365 (100,
M+). Anal. Calcd for C10H12NO2Re: C, 32.96; H, 3.32; N, 3.84.
Found: C, 32.69; H, 3.41; N, 3.57.
C
13H14NO2Re: C, 38.80; H, 3.51; N, 3.48. Found: C, 38.56;
H, 3.82; N, 3.71.
Gen er a l P r oced u r e for th e P r ep a r a tion of [(CO)2(R)-
ReNH(CH3)CH2CH2(η5-C5H4)]+Br - (7e-g; R ) CH2CO2CH3,
CH2CO2C2H5, CH 2CN). Over a period of 3 min, a hexane
solution of n-BuLi (1.6 M, 0.75 mL, 1.2 mmol) was added to a
stirred solution of 3 (365 mg, 1.0 mmol) in THF (15 mL) at
-78 °C. After the mixture was stirred for an additional 10
min, an electrophile (BrCH2CO2CH3, BrCH2CO2C2H5, or BrCH2-
CN; 2-3 mmol) was added. The cool bath was removed, and
the resulting solution was stirred at room temperature for 20-
30 min. The infrared spectra showed the terminal carbonyl
stretching frequencies at 1896 and 1824 cm-1, suggesting that
the intermediate is the neutral amidorhenium complex 6. One
drop of water was then added. Solvents were evaporated to
dryness. The resulting yellow-brown solids were extracted
with CH2Cl2. After filtration, CH2Cl2 was evaporated until
about 10 mL was left. Ether was added to effect precipitation.
Solids were collected and washed twice with ether to give 7e-g
in 53-80% yield.
Gen er a l P r oced u r e for th e P r ep a r a tion of (CO)2ReNR-
(CH3)CH2CH2(η5-C5H4) (5a -d ; R ) Meth yl, Allyl, Ben zyl,
P r op a r gyl). Over a period of 3 min, a hexane solution of
n-BuLi (1.6 M, 0.75 mL, 1.2 mmol) was added to a stirred
solution of 3 (365 mg, 1.0 mmol) in THF (15 mL) at -78 °C.
After the mixture was stirred for an additional 10 min, an
electrophile (CH3I, CH2dCHCH2Br, C6H5CH2Br, or HCtCCH2-
Br; 2-3 mmol) was added. After another 5 min of stirring,
the cool bath was removed and the solution was stirred at room
temperature for 20-30 min. The resulting yellow-brown
solution was concentrated and flash-column-chromatographed
on silica gel (230-400 mesh) upon elution with 10-30% EtOAc
in hexanes. The first yellow band was collected and concen-
trated to provide the desired product in 67-78% yield.
(CO)2ReN(CH3)2CH2CH2(η5-C5H4) (5a ): pale yellow crystal
(72% yield). Mp: 195 °C dec. This compound has been
reported previously.11
[(CO)2(CH2CO2CH3)ReNH(CH 3)CH2CH2(η5-C5H4)]+Br -
(7e): yellow crystal (80% yield). Mp: 148 °C dec. IR (CH2-
Cl2): 2051 (s), 1975 (s), 1696 (m) cm-1 1H NMR (CDCl3, 300
.
(CO)2ReN(CH3)(CH2CHdCH2)CH2CH2(η5-C5H4) (5b): yel-
low crystal (78% yield). Mp: 86-88 °C. IR (CH2Cl2): 1898
MHz): δ 9.16-9.04 (1H, br s, N-H), 7.11-7.09 (1H, m, Cp
H), 6.45-6.43 (1H, m, Cp H), 5.14-5.12 (1H, m, Cp H), 5.02-
5.00 (1H, m, Cp H), 4.34-4.28 (1H, m, H1a), 3.65 (3H, s,
-OCH3), 3.62-3.46 (1H, m, H1b), 3.07 (1H, ddd, J ) 13.4, 12.8,
6.3 Hz, H2a), 2.94 (3H, d, J ) 5.6 Hz, N-CH3), 2.56 (2H, s,
Re-CH2R), 2.33 (1H, dd, J ) 13.4, 6.2 Hz, H2b). 13C NMR
(CDCl3, 75 MHz): δ 196.9 (CO), 193.7 (CO), 179.3 (-COOCH3),
130.4 (C, Cp), 93.6 (CH, Cp), 91.0 (CH, Cp), 88.5 (CH, Cp),
87.4 (CH, Cp), 79.3 (CH2, C1), 51.2 (CH3, -OCH3), 48.7 (CH3,
N-CH3), 24.3 (CH2, C2), -12.7 (CH2, Re-CH2R). Mass
spectrum (FAB, 187Re; m/ e (relative intensity (%)): 438 (100,
M+), 410 (13, M+ - CO). Anal. Calcd for C13H17BrNO4Re: C,
30.18; H, 3.31; N, 2.71. Found: C, 29.85; H, 3.35; N, 2.93.
[ ( C O ) 2 ( C H 2 C O 2 C 2 H 5 ) R e N H ( C H 3 ) C H 2 C H 2 ( η5 -
C5H4)]+Br - (7f): hygroscopic solid (75% yield). IR (CH2Cl2):
(s), 1823 (s) cm-1 1H NMR (CDCl3, 300 MHz): δ 6.26-6.13
.
(1H, m, internal olefinic H), 5.43 (1H, doublets of multiplet, J
) 9.9 Hz, terminal olefinic Hc), 5.32 (1H, doublets of multiplet,
J ) 17 Hz, terminal olefinic Ht), 5.23-5.21 (1H, m, Cp H),
5.17-5.15 (1H, m, Cp H), 4.90-4.87 (1H, m, Cp H), 4.88-4.85
(1H, m, Cp H), 3.86 (1H, dd, J ) 12.8, 5.6 Hz, allylic Ha), 3.54
(1H, dd, J ) 12.8, 8.2 Hz, allylic Hb), 3.44-3.28 (2H, m, H1’s),
3.07 (3H, s, N-CH3), 2.35-2.15 (2H, m, H2’s). 13C NMR
(CDCl3, 75 MHz): δ 205.5 (CO), 205.0 (CO), 133.6 (CH,
internal olefin), 122.1 (CH2, terminal olefin), 119.6 (C, Cp), 82.0
(CH, Cp), 78.8 (CH2, C1), 78.2 (CH, Cp), 75.9 (CH2, Re-CH2),
75.7 (CH, Cp), 73.9 (CH, Cp), 58.9 (CH3), 24.7 (CH2, C2). Mass
spectrum (FAB, 187Re; m/ e (relative intensity (%)): 406 (80,
M+ + 1), 404 (100), 377 (86, M+ - CO), 362 (16, M+ - CO -
CH3), 349 (68, M+ - 2CO), 334 (20, M+ - 2CO - CH3). Anal.
Calcd for C13H16NO2Re: C, 38.60; H, 3.99; N, 3.46. Found:
C, 38.72; H, 4.15; N, 3.13.
2050 (s), 1981 (s), 1695 (m) cm-1
.
1H NMR (CDCl3, 300
MHz): δ 9.35-9.25 (1H, br s, N-H), 7.20-7.18 (1H, m, Cp
H), 6.25-6.23 (1H, m, Cp H), 5.18-5.16 (1H, m, Cp H), 5.03-
5.01 (1H, m, Cp H), 4.37-4.30 (1H, m, H1a), 4.11 (1H, dq, J )
10.9, 7.0 Hz, -OEt), 4.07 (1H, dq, J ) 10.9, 7.0 Hz, -OEt),
3.51-3.37 (1H, m, H1b), 3.15 (1H, td, J ) 13.0, 6.3 Hz, H2a),
2.93 (3H, d, J ) 5.7 Hz, N-CH3), 2.54 (2H, s, Re-CH2), 2.24
(1H, dd, J ) 13.4, 6.3 Hz, H2b), 1.28 (3H, t, J ) 7.0 Hz, -OEt).
13C NMR (CDCl3, 75 MHz): δ 196.7 (CO), 193.8 (CO), 178.6
(-CO2Et), 130.2 (C, Cp), 93.5 (CH, Cp), 90.5 (CH, Cp), 88.6
(CH, Cp), 87.1 (CH, Cp), 79.1 (CH2, C1), 59.9 (CH2, -OEt), 48.5
(CH3, N-CH3), 24.1 (CH2, C2), 13.9 (CH3, -OEt), -12.7 (CH2,
Re-CH2). Mass spectrum (FAB, 187Re; m/ e (relative intensity
(%)): 452 (100, M+), 424 (16, M+ - CO). Anal. Calcd for
(CO)2ReN(CH3)(CH2C6H5)CH2CH2(η5-C5H4) (5c): yellow
crystal (75% yield). Mp: 167 °C dec. IR (CH2Cl2): 1897 (s),
1821 (s) cm-1 1H NMR (CDCl3, 300 MHz): δ 7.39-7.30 (3H,
.
m), 7.23-7.19 (2H, m), 5.28-5.26 (1H, m, Cp H), 5.22-5.20
(1H, m, Cp H), 4.90-4.88 (1H, m, Cp H), 4.88-4.86 (1H, m,
Cp H), 4.65 (1H, d, J ) 13.8 Hz, benzylic Ha), 4.59 (1H, d, J )
13.8 Hz, benzylic Hb), 3.45-3.36 (1H, m, H1a), 3.21-3.14 (1H,
m, H1b), 3.14 (3H, s), 2.30 (1H, dt, J ) 14.6, 5.5 Hz, H2a), 2.19
(1H, ddd, J ) 14.6, 8.7, 5.1 Hz, H2b). 13C NMR (CDCl3, 75
MHz): δ 205.4 (CO × 2), 132.6 (C, Ph), 131.6 (CH × 2, Ph),
128.6 (CH, Ph), 128.3 (CH × 2, Ph), 119.7 (C, Cp), 81.1 (CH,
Cp), 79.2 (CH, Cp), 77.2 (CH2, benzylic), 75.0 (CH, Cp), 74.9
(CH2, C1), 74.2 (CH, Cp), 58.1 (CH3), 24.9 (CH2, C2). Mass
spectrum (FAB, 187Re; m/ e (relative intensity (%)): 455 (100,
M+), 364 (60, M+ - benzyl). Anal. Calcd for C17H18NO2Re:
C, 44.92; H, 3.99; N, 3.08. Found: C, 44.63; H, 3.82; N, 2.94.
(CO)2ReN(CH3)(CH2CtCH)CH2CH2(η5-C5H4) (5d ): yel-
low liquid (67% yield). IR (CH2Cl2): 3300 (w), 1902 (s), 1825
C
14H19BrNO4Re: C, 31.64; H, 3.60; N, 2.64. Found: C, 31.18;
H, 3.75; N, 2.78.
[(CO)2(CH2CN)ReNH(CH 3)CH2CH2(η5-C5H4)]+Br - (7g):
yellow solid (53% yield). Mp: 145 °C dec. IR (CH2Cl2): 2219
(w), 2055 (s), 1986 (s) cm-1
.
1H NMR (C3D6O, 300 MHz): δ
9.49-9.39 (1H, br s, N-H), 7.12-7.10 (1H, m, Cp H), 6.88-
6.86 (1H, m, Cp H), 5.70-5.68 (1H, m, Cp H), 5.31-5.29 (1H,
m, Cp H), 4.19-4.12 (1H, m, H1a), 3.78-3.69 (1H, m, H1b),
3.00-2.94 (1H, m, H2a), 2.91 (3H, d, J ) 5.7 Hz, N-CH3), 2.45-
2.33 (3H, m, H2b and Re-CH2CN). 1H NMR (CD3OD, 300
MHz): δ 6.77-6.75 (1H, m, Cp H), 6.61-6.59 (1H, m, Cp H),
5.43-5.41 (1H, m, Cp H), 5.36-5.34 (1H, m, Cp H), 4.04 (1H,
ddd, J ) 11.4, 4.7, 3.4 Hz, H1a), 3.72-3.62 (1H, m, H1b), 2.98
1
(s) cm-1; terminal acetylenic absorption was not observed. H
NMR (CDCl3, 300 MHz): δ 5.24-5.22 (1H, m, Cp H), 5.19-
5.17 (1H, m, Cp H), 4.89-4.85 (2H, m, Cp H’s), 4.19 (1H, dd,
J ) 17, 2.5 Hz, acetylenic Ha), 4.17 (1H, dd, J ) 17, 2.5 Hz,
acetylenic Hb), 3.62-3.53 (1H, m, H1a), 3.49-3.41 (1H, m, H1b),

1222 Organometallics, Vol. 16, No. 6, 1997
Wang et al.
Ta ble 1. Cr ysta llogr a p h ic Da ta a n d Str u ctu r e
Refin em en ts for 8
(3H, s, N-CH3), 2.43-2.38 (2H, m), 2.35 (2H, s, Re-CH2CN).
13C NMR (CD3OD, 75 MHz): δ 197.3 (CO), 196.2 (CO), 133.5
(CN), 127.9 (C, Cp), 94.0 (CH, Cp), 92.0 (CH, Cp), 91.1 (CH,
Cp), 90.0 (CH, Cp), 79.0 (CH2, C1), 50.4 (CH3, N-CH3), 26.2
(CH2, C2), -37.7 (CH2, Re-CH2CN). Mass spectrum (FAB,
187Re; m/ e (relative intensity (%)): 405 (95, M+), 377 (12, M+
- CO), 154 (100). Anal. Calcd for C12H14BrN2O2Re: C, 29.76;
H, 2.91; N, 5.78. Found: C, 30.04; H, 2.98; N, 5.93.
formula
fw
C41H39BNO2Re
774.77
cryst size (mm)
cryst syst
space group
a (Å)
b (Å)
c (Å)
0.13 × 0.16 × 0.44
monoclinic
P21/c
10.163(3)
19.329(3)
17.145(3)
100.078(20)
3315.9(13)
4
Rea ction of 3 w ith Electr op h iles: Gen er a l P r oced u r e
for th e P r ep a r a tion of [(CO)2(R)ReNH(CH3)CH2CH2(η5-
C5H4)]+X- (7a -g; R ) CH3, CH2CHdCH2, CH2C6H5, CH2-
CtCH, CH2CO2CH3, CH2CO2C2H5, CH2CN; X ) I for 7a
a n d X ) Br for 7b-g). For complexes 7a , 7c, and 7d , a sus-
pension of 3 (364 mg, 1 mmol) in 3 mL of electrophile (CH3I,
BrCH2C6H5, or BrCH2CtCH) was stirred at room tempera-
ture. Solids were dissolved gradually during the course of the
reaction. The progress of the reaction was monitored by
checking the carbonyl absorptions in the infrared spectrum.
After the reaction was complete (30 min to 2 h), ether was
added to allow the product to precipitate. The precipitates
were washed twice with ether to give 7a , 7c, and 7d ,
respectively. For complexes 7b , 7e, 7f and 7g, the amino-
rhenium complex 3 (364 mg, 1 mmol) was dissolved in CH2-
Cl2 (2 mL). Three equivalents of electrophile (BrCH2CHdCH2,
BrCH2CO2CH3, BrCH2CO2C2H5, or BrCH2CN) was then added.
The solution was stirred at room temperature. After the
carbonyl absorptions of 3 disappeared in the infrared spectrum
(30 min to several hours), ether was added to allow the product
to precipitate. The precipitates were washed twice with ether
to give 7b, 7e, 7f, and 7g, respectively.
â (deg)
V (Å3)
Z
Dc (g cm-3
F(000)
)
1.552
1547
λ(Mo KR) (Å)
µ(Mo KR) (cm-1
transmissn
0.710 69
37.491
0.898; 1.000
2.06-8.24
2(0.90 + 0.35 tan θ)
45.0
)
scan speed (deg min-1
θ/2θ scan width (deg)
2θmax (deg)
)
unit cell detn: no.; 2θ range (deg) 25; 15.84-32.72
hkl range
(-10 to +10), (0-20), (0-18)
4606
4320
3243
415
0.026; 0.026
1.19
0.000 100
+0.660; -0.510
no. of collected rflns
no. of unique rflns
no. of obsd rlfns (I > 2.5σ(I))
no. of refined params
RF;a Rw
b
GOF
2
weight modifier k in kFo
(∆F)max,min (e Å-3
)
a
b
2 1/2
RF ) ∑(Fo - Fc)/∑(Fo). Rw ) [∑w(Fo - Fc)2/∑wFo
] .
[(CO)2(CH3)ReNH(CH3)CH2CH2(η5-C5H4)]+I- (7a ): yellow
solid (97% yield). Mp: 120-122 °C dec. IR (CH2Cl2): 2040
1966 (s) cm-1
.
1H NMR (CDCl3, 300 MHz): δ 9.00 (1H, br s,
(s), 1971 (s) cm-1 1H NMR (CDCl3, 300 MHz): δ 8.34 (1H, br
.
N-H), 7.25-7.20 (2H, m, Ph), 7.09-7.04 (3H, m, Ph), 6.88-
6.86 (1H, m, Cp H), 6.17-6.15 (1H, m, Cp H), 4.33-4.31 (1H,
m, Cp H), 4.28-4.26 (1H, m, Cp H), 4.18-4.12 (1H, m, H1a),
3.56 (1H, d, J ) 10.5 Hz, benzylic Ha), 3.42 (1H, d, J ) 10.5
Hz, benzylic Hb), 3.36-3.25 (1H, m, H1b), 3.12 (1H, td, J )
13.1, 6.0 Hz, H2a), 2.94 (3H, d, J ) 5.7 Hz, N-CH3), 2.12 (1H,
dd, J ) 13.5, 5.7 Hz, H2b). 13C NMR (CDCl3, 75 MHz): δ 198.2
(CO), 196.8 (CO), 147.2 (C, Ph), 130.1 (C, Cp), 127.8 (CH × 2,
Ph), 127.2 (CH × 2, Ph), 125.2 (CH, Ph), 92.9 (CH, Cp), 90.7
(CH, Cp), 88.4 (CH, Cp), 88.2 (CH, Cp), 77.8 (CH2, C1), 48.8
(CH3, N-CH3), 24.3 (CH2, C2), -2.7 (CH2, Re-CH2Ph). Mass
spectrum (FAB, 187Re; m/ e (relative intensity (%)): 456 (100,
M+), 428 (8, M+ - CO), 365 (75, M+ - CH2C6H5). Anal. Calcd
for C17H19BrNO2Re: C, 38.13; H, 3.58; N, 2.62. Found: C,
37.94; H, 3.72; N, 2.68.
s, N-H), 6.93-6.91 (1H, m, Cp H), 6.14-6.12 (1H, m, Cp H),
5.09-5.07 (1H, m, Cp H), 4.70-4.68 (1H, m, Cp H), 4.22-4.17
(1H, m), 3.38-3.15 (2H, m), 2.90 (3H, d, J ) 5.8 Hz, N-CH3),
2.23-2.16 (1H, m), 0.98 (3H, s, Re-CH3). 1H NMR (C3D6O,
300 MHz): δ 8.22 (1H, br s, N-H), 6.74-6.72 (1H, m, Cp H),
6.66-6.64 (1H, m, Cp H), 5.39-5.37 (1H, m, Cp H), 5.15-5.13
(1H, m, Cp H), 4.06-4.01 (1H, m, H1a), 3.69-3.56 (1H, m, H1b),
2.99-2.90 (1H, m, H2a), 2.88 (3H, d, J ) 5.8 Hz, N-CH3), 2.39-
2.33 (1H, ddd, J ) 13.4, 6.0, 1.2 Hz, H2b), 0.96 (3H, s, Re-
CH3). 1H NMR (CD3OD, 300 MHz): δ 7.39 (1H, br s, N-H),
6.58-6.56 (1H, m, Cp H), 6.43-6.41 (1H, m, Cp H), 5.18-5.15
(2H, m, Cp H), 4.01-3.94 (1H, m), 3.71-3.55 (1H, m), 2.99
(3H, d, J ) 5.8 Hz, N-CH3), 2.53-2.36 (2H, m), 0.98 (3H, s,
Re-CH3). 13C NMR (CD3OD, 75 MHz): δ 198.4 (CO), 197.4
(CO), 130.3 (C, Cp), 91.8 (CH, Cp), 90.4 (CH, Cp), 89.3 (CH,
Cp), 88.1 (CH, Cp), 77.5 (CH2), 50.7 (CH3, N-CH3), 26.4 (CH2),
-27.6 (CH3, Re-CH3). Mass spectrum (FAB, 187Re; m/ e
(relative intensity (%)): 380 (100, M+). Anal. Calcd for
[(CO)2(CH 2CtCH )R eNH (CH 3)CH 2CH 2(η5-C5H 4)]+Br -
(7d ): yellow solid (98% yield). Mp: 134-139 °C dec. IR (CH2-
Cl2): 2047(s), 1978(s) cm-1
.
1H NMR (CDCl3, 300 MHz): δ
9.16 (1H, br s, N-H), 7.15-7.13 (1H, m, Cp H), 6.25-6.23 (1H,
m, Cp H), 5.38-5.36 (1H, m, Cp H), 4.90-4.88 (1H, m, Cp H),
4.27-4.20 (1H, m, H1a), 3.43-3.29 (1H, m, H1b), 3.14 (1H, ddd,
J ) 13.4, 12.6, 6.1 Hz, H2a), 2.94 (3H, d, J ) 5.7 Hz, N-CH3),
2.43 (1H, dd, J ) 15.4, 2.8 Hz, acetylenic Ha), 2.35 (1H, dd, J
) 15.4, 2.8 Hz, aceylenic Hb), 2.20 (1H, dd, J ) 13.4, 6.1 Hz,
C
11H15INO2Re: C, 26.09; H, 2.99; N, 2.77. Found: C, 25.85;
H, 3.06; N, 2.82.
[ ( C O ) 2 ( C H 2 C H dC H 2 ) R e N H ( C H 3 ) C H 2 C H 2 ( η5 -
C5H4)]+Br - (7b): unstable yellow solid (80% yield, about 90%
purity). IR (CH2Cl2): 2034 (s), 1967 (s) cm-1 1H NMR (CDCl3,
.
H
2b), 2.09 (1H, t, J ) 2.8 Hz, alkyne-H). 13C NMR (CDCl3,
300 MHz): δ 8.74 (1H, br s, N-H), 6.90-6.88 (1H, m, Cp H),
6.36-6.34 (1H, m, Cp H), 6.02-5.85 (1H, m, internal olefinic
H), 4.90-4.88 (1H, m, Cp H), 4.69 (1H, dd, J ) 16.5, 1.2 Hz,
terminal olefinic Ht), 4.64 (1H, dd, J ) 9.8, 1.2 Hz, terminal
olefinic Hc), 4.42-4.40 (1H, m, Cp H), 4.23-4.13 (1H, m, H1a),
3.63-3.57 (1H, m, allylic Ha), 3.46-3.35 (1H, m, H1b), 3.08-
2.97 (1H, m, H2a), 2.94 (3H, d, J ) 5.6 Hz, N-CH3), 2.78-2.73
(1H, m, allylic Hb), 2.28-2.21 (1H, m, H2b). 13C NMR (CDCl3,
75 MHz): δ 197.7 (CO), 195.6 (CO), 142.3 (CH, dCHR), 128.8
(C, Cp), 111.6 (CH2, dCH2), 94.0 (CH, Cp), 90.9 (CH, Cp), 88.9
(CH, Cp), 88.1 (CH, Cp), 78.0 (CH2, C1), 49.3 (CH3, N-CH3),
24.5 (CH2, C2), -2.0 (CH2, Re-CH2). Mass spectrum (FAB,
187Re; m/ e (relative intensity (%)): 406 (100, M+), 365 (45, M+
- C3H5).
75 MHz): δ 197.1 (CO), 194.3 (CO),129.7 (C, Cp), 93.9 (CH,
Cp), 90.9 (CH, Cp), 90.3 (C, RCt), 89.5 (CH, Cp), 87.7 (CH,
Cp), 78.5 (CH2, C1), 69.8 (CH, tCH), 49.3 (CH3, N-CH3), 24.6
(CH2, C2), -28.6 (CH2, Re-CH2). Mass spectrum (FAB,
187Re; m/ e (relative intensity (%)): 404 (4, M+). Anal. Calcd
for C13H15BrNO2Re: C, 32.30; H, 3.13; N, 2.90. Found: C,
32.25; H, 3.28; N, 3.03.
[(CO)2(CH2CO2CH3)ReNH(CH 3)CH2CH2(η5-C5H4)]+Br -
(7e): yellow crystal (90% yield).
[ ( C O ) 2 ( C H 2 C O 2 C 2 H 5 ) R e N H ( C H 3 ) C H 2 C H 2 ( η5 -
C5H4)]+Br - (7f): hygroscopic solid (83% yield).
[(CO)2(CH2CN)ReNH(CH 3)CH2CH2(η5-C5H4)]+Br - (7g):
yellow solid (75% yield).
[(CO)2(CH2C6H5)ReNH(CH3)CH2CH2(η5-C5H4)]+Br - (7c):
hygroscopic yellow solid (90% yield). IR (CH2Cl2): 2034 (s),
P r ep a r a tion a n d cr ysta l str u ctu r e of [(CO)2(CH2C6H5)-
-
R eNH (CH3)CH2CH 2(η5-C5H 4)]+BP h 4 (8). Sodium tetra-

Half-Sandwich Aminorhenium Complexes
Organometallics, Vol. 16, No. 6, 1997 1223
Ta ble 2. Selected Bon d Len gth s (Å) a n d Bon d
An gles (d eg) for 8
CAD-4 automated diffractometer by use of a graphite-mono-
chromated Mo KR radiation (λ ) 0.710 69 Å) with the θ-2θ
scan mode. The unit cell was determined and refined using
25 randomly seleced reflections obtained with the automatic
search, center, index, and least-squares routines. Lorentz/
polarization and empirical absorption corrections based on
three azimuthal scans were applied to the data. The space
group (P21/n) was determined from the systematic absences
observed during data collection. All data reduction and
refinements were carried out on a DecAlpha 3400/400 com-
puter using the NRCVAX program.14 The structure was solved
by direct methods and refined by a full-matrix least-squares
routine15 with anisotropic thermal parameters for all non-
Re-N
2.223(5))
2.337(7))
1.949(6)
1.935(7)
N-C(1)
1.493(9)
1.114(8)
1.139(8)
1.491(10)
Re-C(9)
Re-C(16)
Re-C(17)
C(16)-O(16)
C(17)-O(17)
C(2)-C(3)
N-Re-C(9)
144.6(2)
C(16)-Re-C(17)
C(1)-C(2)-C(3)
Re-C(16)-O(16)
Re-C(17)-O(17)
Re-C(9)-C(10)
103.2(3)
107.6(6)
173.9(5)
177.3(6)
119.4(4)
N-Re-C(16)
N-Re-C(17)
C(9)-Re-C(16)
C(9)-Re-C(17)
84.5(2)
84.2(2)
73.2(2)
74.8(2)
phenylborate (140 mg, 0.4 mmol) was added to a yellow
solution of complex 7c (107 mg, 0.2 mmol) in methanol (4 mL)
at room temperature. The mixture was shaken until NaBPh4
dissolved. The solution was then cooled in a freezer (-20 °C)
for 20 h. Orange solids were collected and washed twice with
methanol to give 145 mg (94%) of 8. Recrystallization of 8
from CH2Cl2/hexane gave yellow needles. Mp: 144-146 °C
hydrogen atoms. The structure was refined by minimizing
2
∑w|Fo
- Fc| , where w ) (1/σ2)Fo was calculated from the
counting statistics. Hydrogens were included in the structure
factor calculations in their expected positions on the basis of
idealized bonding geometry but not refined in least squares.
The final cell parameters and data collection parameters are
listed in Table 1 and selected bond distances and angles in
Table 2.
dec. IR (CH2Cl2): 2035 (s), 1964 (s) cm-1 1H NMR (CD2Cl2,
.
300 MHz): δ 7.45-7.39 (8H, m), 7.27-7.22 (3H, m), 7.12-
7.04 (10H, m), 6.94-6.89 (4H, m), 5.96-5.94 (1H, Cp H), 5.91-
5.89 (1H, Cp H), 4.31-4.29 (1H, Cp H), 4.26-4.24 (1H, Cp H),
3.48 (1H, d, J ) 10.4 Hz, benzylic Ha), 3.39 (1H, d, J ) 10.4
Hz, benzylic Hb), 3.19-3.11 (1H, m, H1a), 2.91-2.81 (1H, m,
Ack n ow led gm en t. We are grateful to the National
Science Council of Taiwan, ROC, for financial support.
H
1b), 2.64 (3H, d, J ) 5.8 Hz, N-CH3), 1.77-1.72 (2H, m, H2’s).
Su p p or tin g In for m a tion Ava ila ble: Tables of data col-
lection parameters, bond lengths and bond angles, fractional
atomic coordinates, and anisotropic thermal parameters for 8
(6 pages). Ordering information is given on any current
masthead page.
1H NMR (C3D6O, 300 MHz): δ 7.36-7.30 (8H, m), 7.25-7.18
(4H, m), 7.10-7.03 (1H, m), 6.92 (8H, t, J ) 7.4 Hz), 6.79 (4H,
t, J ) 7.4 Hz), 6.69-6.67 (1H, Cp H), 6.47-6.45 (1H, Cp H),
4.90-4.88 (1H, Cp H), 4.78-4.76 (1H, Cp H), 4.16-4.08 (1H,
m, H1a), 3.83-3.70 (1H, m, H1b), 3.53 (2H, s, benzylic H’s), 3.12
(3H, d, J ) 5.8 Hz, N-CH3), 2.45-2.40 (2H, m, H2’s). Mass
spectrum (FAB, 187Re; m/ e (relative intensity (%)): 456 (32,
M+), 365 (12, M+ - C7H7). Anal. Calcd for C41H39BNO2Re:
C, 63.56; H, 5.07; N, 1.81. Found: C, 63.61; H, 5.12; N, 1.85.
A single crystal of 8 was obtained by slow diffusion of a CH2-
Cl2 solution of 8 into hexane at 5 °C for several days.
Diffraction measurement was made on an Enraf-Nonius
OM960980P
(14) Gabe, E. J .; LePage, Y.; Charland, J . P.; Lee, F. L; White, P. S.
J . Appl. Crystallogr. 1989, 22, 384.
(15) Main, P. In Crystallographic Computing 3: Data Collection,
Structure Determination, Proteins and Databases; Sheldrick, G. M.,
Krueger, C., Goddard, R., Eds.; Clarendon Press: Oxford, U.K., 1985;
pp 206-215.