Selective reaction of aminorhenium complexes and the formation of Cp-N-P tridentate complexes

Article abstract of DOI:10.1002/ejic.200300650

Rhenium complexes containing cyclopentadienyl-aminophosphanyl tridentate ligands have been prepared starting from a cyclopentadienyl-amino bidentate complex in a controlled manner. Dehydrobromination of [η⁵: η¹-C₅H₄CH₂CH ₂NH(CH₃)Re(CO)₂Br]⁺ (2) was carried out selectively at low temperature to give an exocyclic iminorhenium complex [η⁵:η¹-C₅H₄CH ₂CH₂N(=CH₂)Re(CO)₂]. (5). Selective N-methylation provided a cationic heterocyclopropane complex 8 which reacted with various nucleophiles (tBuNH₂, NaOCH₃, KPPh ₂) to give precursors for tridentate complexes. A formal oxidation of the carbonyl ligand to a labile carbon dioxide ligand was accomplished by oxidation with peroxy acid. Intramolecular N ligand displacement furnished the Cp-N-P tridentate complex. The relative stability of the N, P and CO ligands was revealed when an η³-allyl ligand was formed. The N ligand became detached from the metal rather than the P or CO ligands as the η¹-allyl was transformed to the corresponding η³-allyl coordination mode. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Full text of DOI:10.1002/ejic.200300650

FULL PAPER
Selective Reaction of Aminorhenium Complexes and the Formation of Cp-N-P
Tridentate Complexes
Tein-Fu Wang,*[a] Tan-Ching Wang,[a] and Yuh-Sheng Wen[a]
Keywords: Rhenium / Cyclopentadienes / N ligands / P ligands / Tridentate ligands
Rhenium complexes containing cyclopentadienyl-amino-
phosphanyl tridentate ligands have been prepared starting
complexes. A formal oxidation of the carbonyl ligand to a
labile carbon dioxide ligand was accomplished by oxidation
with peroxy acid. Intramolecular N ligand displacement fur-
nished the Cp-N-P tridentate complex. The relative stability
of the N, P and CO ligands was revealed when an η3-allyl
from
controlled
C5H4CH2CH2NH(CH3)Re(CO)2Br]+ (2) was carried out se-
a
cyclopentadienyl-amino bidentate complex in
a
manner. Dehydrobromination of
[η5:η1-
lectively at low temperature to give an exocyclic iminorhen- ligand was formed. The N ligand became detached from the
ium complex [η5:η1-C5H4CH2CH2N(=CH2)Re(CO)2] (5). Se- metal rather than the P or CO ligands as the η1-allyl was
lective N-methylation provided a cationic heterocyclopro- transformed to the corresponding η3-allyl coordination mode.
pane complex 8 which reacted with various nucleophiles ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
(tBuNH2, NaOCH3, KPPh2) to give precursors for tridentate Germany, 2004)
Introduction
Results and Discussion
Transition metal Cp complexes containing an amino
group functionalized side chain are of considerable current
interest.[1] The majority of studies have concentrated on
complex formation with early transition metals and their
behavior as the ethylene polymerization catalysts.[2] Rela-
tively little is known about the chemistry with low-valent
transition metals. Amino groups have no π-acceptor capa-
bilities, they coordinate only weakly to low-valent metals
and form relatively labile complexes. Through chelation,
several stable low-valent organometallic complexes have
been realized.[3] With the strong electron donating amino
group coordinated to the metal, the complexes show unpre-
cedented chemical properties. We have reported aminorhen-
ium complexes containing η2-carbamoyl,[4] η3-benzyl[5] and
η2-carbon dioxide[6] functionalities. These complexes are
quite stable under ambient conditions and further explo-
ration of the chemistry of this class of complexes is import-
ant.
Selective Reactions of Iminorhenium Complexes
We have previously reported that treatment of the ami-
norhenium bromide 2 with a base at room temperature af-
forded the η2-carbamoyl complex 4.[4] When the reaction
was carried out at 0 °C, however, a significant amount of
the iminorhenium complex 5 was isolated (Scheme 1). The
reaction presumably proceeds via the neutral intermediate
3, followed by two competitive pathways. Migratory CO in-
sertion gave complex 4, while dehydrobromination gave
complex 5. We assumed that the CO migratory insertion
might be more temperature dependent than that of the de-
hydrobromination. Low temperature reactions were there-
fore tested. Indeed, when 2 was treated with base at Ϫ78
°C, only the dehydrobromination products 5 and 6 (ഠ 3%)
were isolated. The exocyclic imino complex 5 and the endo-
cyclic imino complex 6 that were formed presumably via
1
kinetic control, could be easily differentiated by their H
NMR spectra. There are two imino protons (δ ϭ 7.90 and
7.79 ppm) for 5, while only one imino proton (δ ϭ 7.68
ppm) and a methyl group (δ ϭ 3.81 ppm) for 6.
In this study, we report some selective reactions of the
aminorhenium complexes and ultimate conversion into the
corresponding Cp-N-P tridentate complexes.[7] We intro-
duce a new approach for promoting the carbonyl ligand
substitution for the first time by an unprecedented peroxy
acid oxidation. The synthesis and chemistry are reported
herein.
Unlike the aminorhenium complex 1 in which the alky-
lation occurred selectively at the rhenium center,[8] the
methylation of the exocyclic iminorhenium complex 5
turned out to be non-selective. Both Re- and N-methylation
compounds 7 and 8 were obtained (Scheme 1). The forma-
tion of the Re-methylation compound is faster than that of
the N-methylation compound. When the reaction mixture
was stirred longer, however, the N-methylation compound
7 disappeared gradually by virtue of reversibility and finally
the iminium complex 8 was isolated in good yield. The im-
[a]
Institute of Chemistry, Academia Sinica,
Taipei, Taiwan
E-mail: tfwang@chem.sinica.edu.tw
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 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/ejic.200300650
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Selective Reaction of Aminorhenium Complexes
FULL PAPER
Scheme 1. Selective dehydrobromination and methylation
[9]
˚
inium protons of 8 are shifted upfield to δ ϭ 3.78 and 3.46 neutral rhenium complexes (2.325Ϫ2.356 A). The car-
ppm, respectively, compared with δ ϭ 8.42 and 8.11 ppm bonyl groups are bonded to the rhenium in a linear manner
for complex 7, suggesting that the iminium carbon is as indicated by the bond angles of 175.8° for ReϪC10ϪO10
bonded to the metal center. The N-methyl resonance ap- and 177.3° for ReϪC11ϪO11.
peared at δ ϭ 3.40 ppm indicating that the N ligand re-
mains coordinated. The iminium ligand is therefore better
viewed as a heterocyclopropane ring.
Reactions of the Cationic Complex 8 with Nucleophiles
Treatment of the cationic complex 8 with various nucleo-
philes (tBuNH2, NaOCH3) resulted in the opening of the
heterocyclopropane ring to give the neutral complex 9
(Scheme 2). The physical properties of 9a and 9b are similar
to those of N,N-disubstituted aminorhenium complexes
that we have reported previously.[8] When 8 was treated with
potassium diphenylphosphide, the phosphane-coordinated
complex 10 was obtained. The terminal carbonyl stretching
frequencies of 10 appeared at 1920 and 1848 cmϪ1 com-
pared with 1894 and 1818 cmϪ1 in 9a, and 1899 and 1823
cmϪ1 in 9b. Higher energy shifts of the carbonyl stretching
frequencies of 10 are consistent with the weaker electron
donating ability of the phosphanyl group compared with
that of the amino group. The N-methyl group of 10 ap-
peared at δ ϭ 2.30 ppm compared with δ ϭ 3.08 ppm in
9a and δ ϭ 3.26 ppm in 9b suggesting that the amino group
Scheme 2. Reactions of the heterocyclopropane complex 8 with nu-
cleophiles
of 10 is uncoordinated. The aminorhenium complex 9c was
assumed to be the initial reaction product. Phosphanyl
groups are generally considered to be better ligands for low
valent organometallic complexes than amino groups. The
amino ligand of 9c was therefore substituted intramolecu-
Formation of Cyclopentadienyl-Nitrogen-Phosphorous
Tridentate Complexes
larly by the newly generated phosphanyl group to give 10.
The intramolecular exchange of the two amino groups of
Formation of a Cp-N-P tridentate complex from the rhe-
9a was not observed. Unambiguous characterization of 10 nium phosphane compound 10 requires removal of a car-
was accomplished by a single-crystal X-ray diffraction bonyl ligand. Photochemical[10] and trimethylamine N-ox-
study and Figure 1 shows an ORTEP diagram of 10. The ide promoted[11] CO expulsion have been commonly used
˚
ReϪP bond length is 2.331 A, similar to those reported for for the removal of terminal carbonyl ligands. However,
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T.-F. Wang, T.-C. Wang, Y.-S. Wen
FULL PAPER
ReϪH bond had formed. The product was therefore pro-
posed as the Cp-N-P tridentate complex 13 (Scheme 3). The
reaction presumably proceeds through the rhenium carbon
dioxide complex 11 followed by intramolecular amino
group displacement of the labile CO2 to give the neutral
Cp-N-P tridentate complex 12. The basic rhenium center
picked up a proton and anion exchange furnished com-
plex 13.
Single crystals of 13 were obtained from a solution in
acetone and methanol. An ORTEP drawing of 13 is shown
in Figure 2. Both nitrogen and phosphorous are bonded to
˚
˚
the metal with distances of 2.146 A for ReϪN and 2.363 A
for ReϪP, respectively. The torsion angle of the heterocyclic
4Ϫmembered NϪReϪPϪC8 ring is 10.1°.
˚
Figure 1. ORTEP diagram of 10. Selective bond lengths (A) and
bond angles (°): ReϪP 2.331(2), ReϪC10 1.886(6), ReϪC11
1.874(6); PϪReϪC10 94.2(2), PϪReϪC11 88.6(2), ReϪC10ϪO10
175.8(6), ReϪC11ϪO11 177.3(5)
these methodologies are not useful for complex 10, owing
˜
to the relatively inert carbonyl groups (IR: ν ϭ 1920, 1848
cmϪ1). When 10 was treated with trimethylamine N-oxide
or ultraviolet irradiation, only the starting material was re-
covered accompanied by some decomposition. It has been
reported that an electron-rich aminorhenium complex such
as A (Scheme 3), reacts with electrophilic peroxy acids to
provide the CO2 complex B.[6] Although the phosphanyl li-
gand is less electron donating than the amino ligand, we
anticipated that the rhenium phosphane complex 10 would
still be reactive enough with elctrophilic peroxy acids. In-
deed, when 10 was treated with m-chloroperbenzoic acid, a
carbonyl group disappeared immediately. Only one car-
bonyl stretch appeared at 1926 cmϪ1 in the resultant infra-
red spectrum. The resonance of the N-methyl group ap-
1
Figure 2. ORTEP drawing of the cationic part of 13. Selective bond
peared at δ ϭ 3.41 ppm in the H NMR spectrum indicat-
ing that the amino group had become coordinated to the
metal. A hydride appeared at δ ϭ Ϫ6.15 suggesting that a 90.8(3), PϪReϪC10 100.5(2)
˚
lengths (A) and bond angles (°): ReϪP 2.363(2), ReϪN 2.146(7),
PϪC8 1.828(7), NϪC8 1.467(11); PϪReϪN 67.5(2), NϪReϪC10
Scheme 3. Formation of a Cp-N-P tridentate complex
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Eur. J. Inorg. Chem. 2004, 1668Ϫ1674

Selective Reaction of Aminorhenium Complexes
FULL PAPER
Reaction of the Cp-N-P Tridentate Complex with
Electrophiles
phosphanyl ligand towards the cationic metal center. To our
surprise, however, the amino group was expelled in prefer-
ence to the phosphanyl or the CO groups when the η3-allyl
complex was formed.
The spontaneous protonation of the neutral Cp-N-P tri-
dentate complex 12 to give the cationic complex 13
prompted us to investigate nucleophilic reactions of 12
(Scheme 3). Complex 12 was regenerated from the cationic
13 by deprotonation with nBuLi. Treatment of 12 with vari-
ous electrophiles (N-bromosuccinimide, methyl iodide,
benzyl bromide) gave the expected products 14aϪc in excel-
lent yield (Scheme 4). The spectroscopic properties of
14aϪc appeared similar to those of 13. The N-methyl
1
groups appeared at δ ϭ 3.36Ϫ3.52 ppm in the H NMR
spectra suggesting that the amino groups remained coordi-
nated. The ReϪCH3 methyl protons of 14b and the Re-
benzyl methylene protons of 14c show 3J couplings with the
phosphorous indicating that the alkylations were successful
and that the phosphanyl ligands remain coordinated to the
metal. The carbonyl stretching appeared at 1918 cmϪ1 for
both 14b and 14c. A relatively higher stretching frequency
appeared at 1953 cmϪ1 for 14a, consistent with the presence
of the electronegative bromine on the metal. Complex 14a
could also be obtained by direct treatment of 13 with N-
bromosuccinimide.
Figure 3. ORTEP drawing of the cationic part of 15. Selective bond
˚
lengths (A) and bond angles (°): ReϪP 2.414(2), ReϪC11 2.257(8),
ReϪC12 2.200(9), ReϪC13 2.244(8); PϪReϪC10 82.7(2),
PϪReϪC11 79.5(2), PϪReϪC12 92.1(2), PϪReϪC13 126.8(2),
C11ϪC12ϪC13 119.0(8)
Conclusion
We have demonstrated that CO migratory insertion and
dehydrobromination can be carried out selectively by tem-
perature control. The CO migratory insertion of compound
3 was drastically reduced at low temperature thereby al-
lowing selective dehydrobromination to give complex 5. By
learning that the rhenium-methylation is reversible, we suc-
cessfully obtained the N-methylation complex 8 exclusively
by prolonged reaction. Introduction of a P ligand was
achieved by nucleophilic addition to the activated methyl-
ene group of the iminium ligand. Removal of a carbonyl
ligand was demonstrated for the first time using a peroxy
acid which formally oxidized the CO to a labile CO2 ligand.
Intramolecular ligand displacement furnished the Cp-N-P
tridentate complex. It is worth noting that when the η1-allyl
was transformed to η3-allyl, the N ligand of the cationic
tridentate complex 14c was detached from the metal to
give 15.
Scheme 4. Reaction of the tridentate complex 13 and selective re-
moval of the N ligand
The reaction of 12 with allyl bromide doesn’t stop at the
η1-allyl complex 14d, but proceeds further to give the η3-
1
allyl complex 15. Examination of the H NMR spectrum
showed that the NϪCH3 group appeared at δ ϭ 1.98 ppm,
indicating that the amino group had become detached from
the metal. A single-crystal X-ray analysis confirmed this as-
signment. Figure 3 shows an ORTEP diagram of 15. The
allyl group is bonded to the rhenium in an η3-fashion with
Experimental Section
˚
bond lengths of 2.257, 2.200 and 2.244 A, respectively. The
General: Infrared solution spectra were recorded with
a
˚
rheniumϪphosphorous bond length is 2.414 A, slight
PerkinϪElmer 882 infrared spectrophotometer using 0.1 mm cells
longer than those in complexes 10 and 13. The amino group
with CaF2 windows. Melting points were determined using a Yan-
was generally thought to be a better ligand than that of the aco Model MP micro melting point apparatus and were uncor-
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T.-F. Wang, T.-C. Wang, Y.-S. Wen
FULL PAPER
rected. 1H NMR (300 MHz), 13C NMR (75 MHz) and 31P{1H}
NMR (121 MHz) were obtained with a Bruker AC-300 FT spec-
trometer. For the assignment of 1H and 13C NMR spectroscopic
data, the carbon bound to the nitrogen was designated as C1 and
the hydrogens on C1 were designated as H1a and H1b. The next
carbon was designated as C2, and the hydrogen atoms on C2 were
designated as H2a and H2b. 1H and 13C chemical shifts are reported
in parts per million (ppm) relative to Me4Si and 31P chemical shifts
on silica gel using 10% followed by 20% ethyl acetate in hexane as
eluents. A yellow band which appeared at Rf ϭ 0.65 (30% EtOAc/
hexane) was collected and concentrated to give a yellow solid
0.122 g (94% yield) of 9a. M.p. 147Ϫ150 °C (dec). IR (CH2Cl2):
1
ν˜ ϭ 1894 s, 1818 s cmϪ1. H NMR (CDCl3): δ ϭ 5.23Ϫ5.21 (m, 1
H, Cp), 5.13Ϫ5.11 (m, 1 H, Cp), 4.92Ϫ4.90 (m, 1 H, Cp),
a
4.89Ϫ4.87 (m, 1 H, Cp), 3.90 (d, J ϭ 11.5 Hz, 1 H, ϪNCH2 NϪ),
3.80 (d, J ϭ 11.5 Hz, 1 H, ϪNCH2bNϪ), 3.40Ϫ3.22 (m, 2 H, H1),
are relative to 85% H3PO4. Elemental analyses were obtained on a 3.08 (s, 3 H, NϪCH3), 2.29Ϫ2.14 (m, 2 H, H2), 1.10 (s, 9 H, tBu)
PerkinϪElmer 2400 CHN elemental analyzer.
ppm. 13C NMR (CDCl3): δ ϭ 205.4 (CO ϫ 2), 119.9 (C, Cp), 81.5
(CH, Cp), 79.0 (CH2, NCH2N), 78.3 (CH, Cp), 75.5 (CH, Cp),
74.3 (CH, Cp), 73.6 (CH2, C1), 56.4 (CH3, NϪCH3), 50.2 (C, tBu),
29.6 (CH3 ϫ 3, tBu), 24.6 (CH2, C2) ppm. C15H23N2O2Re (449.57):
calcd. C 40.07, H 5.16, N 6.23; found C 39.98, H 5.14, N 5.85.
Preparation of [η5:η1-C5H4CH2CH2N(؍CH2)Re(CO)2]: 5 To a
stirred solution of complex 1 (3.44 g, 9.44 mmol) in CH2Cl2
(120 mL) at 0 °C was added a solution of bromine in CH2Cl2
(18.9 mL, 0.5 ) slowly over 15 min. After stirring for an additional
5 min, the resultant orange-red solution was cooled in a dry ice-
acetone bath. A solution of triethylamine (4.5 mL) in CH2Cl2
(45 mL) was then added slowly over 1 h using a syringe pump.
After addition, the cooling bath was removed and the solution was
stirred at room temperature for 30 min. Solvents were then evapo-
rated under reduced pressure. The brown solid residue was chroma-
tographed on silica gel using 20% followed by 30% ethyl acetate in
hexane as eluents. The first yellow band was collected and concen-
trated to give yellow crystalline 5 (2.406 g, 70% yield). A slightly
more polar fraction was collected to give yellow crystalline 6
(0.112 g, 3% yield).
Preparation of 9b: A solution of sodium methoxide in methanol
(0.9 mL, 25 wt%) was added to a stirred solution of 8 (95 mg) in
methanol (10 mL) at room temperature. After stirring for 1.5 h,
methanol was evaporated under reduced pressure. The residue was
extracted with CH2Cl2, concentrated and flash chromatographed
on silica gel using 10% followed by 30% EtOAc in hexane as el-
uents. A yellow band appeared at Rf ϭ 0.62 (50% EtOAc/hexane)
which was collected and concentrated to give the yellow crystalline
complex 9b (70 mg, 90% yield). M.p. 98Ϫ103 °C. IR (CH2Cl2): ν˜ ϭ
1
1899 s, 1823 s cmϪ1. H NMR (CDCl3): δ ϭ 5.25Ϫ5.23 (m, 1 H,
Cp), 5.13Ϫ5.11 (m, 1 H, Cp), 4.95Ϫ4.93 (m, 1 H, Cp), 4.87Ϫ4.85
a
(m, 1 H, Cp), 4.35 (d, J ϭ 8.5 Hz, 1 H, ϪOCH2 ), 4.28 (d, J ϭ
Complex 5: Rf ϭ 0.57 (50% EtOAc in hexane). M.p. 169Ϫ171 °C.
8.5 Hz, 1 H, ϪOCH2b), 3.50Ϫ3.41 (m, 2 H, H1), 3.37 (s, 3 H), 3.26
(s, 3 H), 2.21Ϫ2.12 (m, 2 H, H2) ppm. 13C NMR (CDCl3): δ ϭ
204.6 (CO), 204.5 (CO), 119.6 (C, Cp), 97.0 (CH2, OCH2N), 80.3
(CH, Cp), 79.0 (CH, Cp), 74.9 (CH, Cp), 74.7 (CH, Cp), 73.0 (CH2,
C1), 57.5 (CH3, CH3), 56.6 (CH3), 24.7 (CH2, C2) ppm.
C12H16NO3Re (408.47): calcd. C 35.28, H 3.95, N 3.43; found C
35.29, H 3.70, N 3.30.
IR (CH2Cl2): ν˜ ϭ 1908 s, 1835 s cmϪ1 1H NMR (CDCl3): δ ϭ
.
7.90 (dt, J ϭ 12.9, 1.4 Hz, 1 H, imine), 7.79 (dt, J ϭ 12.9, 1.4 Hz,
1 H, imine), 5.31 (t, J ϭ 2.0 Hz, 2 H, Cp), 5.06 (t, J ϭ 2.0 Hz, 2
H, Cp), 4.34 (tt, J ϭ 6.6, 1.4 Hz, 2 H), 2.18 (t, J ϭ 6.6 Hz, 2 H)
ppm. 13C NMR (CDCl3): δ ϭ 203.6 (CO ϫ 2), 165.4 (CH2, imine),
119.6 (C, Cp), 84.0 (CH2), 80.4 (CH ϫ 2, Cp), 77.1 (CH ϫ 2, Cp),
26.7 (CH2) ppm. C10H10NO2Re (362.40): calcd. C 33.14, H 2.78,
N 3.86; found C 33.31, H 2.62, N 3.95.
Preparation of Complex 10: To a stirred suspension of 8 (1.955 g,
3.987 mmol) in THF (40 mL) at 0 °C was added a red solution of
potassium diphenylphosphide in THF (10.4 mL, 0.5 ) over 5 min.
After addition, the cold bath was removed and the mixture was
stirred at room temperature for 30 min. and then solvents were eva-
porated under reduced pressure. The residue was purified chroma-
tographically on silica gel using 10% followed by 20% EtOAc in
hexane as eluents. A yellow band appeared at Rf ϭ 0.59 (20%
EtOAc/hexane) which was collected and concentrated to give 10
(1.705 g, 80% yield) as a white solid. M.p. 145Ϫ149 °C. IR
Complex 6: M.p. 192Ϫ195 °C (dec). IR (CH2Cl2): ν˜ ϭ 1907 s, 1830
1
s cmϪ1. H NMR (CDCl3): δ ϭ 7.70Ϫ7.67 (m, 1 H, imine), 5.51
(t, J ϭ 2.0 Hz, 2 H, Cp), 5.07 (t, J ϭ 2.0 Hz, 2 H, Cp), 3.82Ϫ3.80
(m, 3 H, CH3), 3.18Ϫ3.15 (m, 2 H) ppm. 13C NMR (CDCl3): δ ϭ
205.2 (CO ϫ 2), 181.2 (CH, imine), 115.7 (C, Cp), 79.3 (CH ϫ 2,
Cp), 77.8 (CH
ϫ 2, Cp), 60.8 (CH3), 35.8 (CH2) ppm.
C10H10NO2Re (362.40): calcd. C 33.14, H 2.78, N 3.86; found C
33.15, H 2.88, N, 3.56.
(CH2Cl2): ν˜ ϭ 1920 s, 1848 s cmϪ1 1H NMR (CDCl3): δ ϭ
.
Preparation of 8: A suspension of complex 5 (0.875 g, 2.41 mmol)
in CH3I (15 mL) was heated under reflux for 5 days. Excess CH3I
was evaporated. The solids was washed four times with CH2Cl2
(5 mL ϫ 4) to give 0.852 g (72% yield) of 8 as a yellow powder.
M.p. 90 °C (dec). IR (CH3CN): ν˜ ϭ 2030 s, 1953 s cmϪ1. 1H NMR
(CD3CN): δ ϭ 6.41Ϫ6.39 (m, 1 H, Cp), 6.37Ϫ6.35 (m, 1 H, Cp),
6.16Ϫ6.14 (m, 1 H, Cp), 5.66Ϫ5.64 (m, 1 H, Cp), 4.29Ϫ4.22 (m, 1
H, H1a), 4.09Ϫ3.98 (m, 1 H, H1b), 3.78 (d, J ϭ 1.7 Hz, 1 H,
7.55Ϫ7.49 (m, 4 H, Ph), 7.39Ϫ7.32 (m, 6 H, Ph), 5.22Ϫ5.20 (m, 2
H, Cp), 5.05Ϫ5.03 (m, 2 H, Cp), 3.68 (s, 2 H, ϪPCH2N),
2.75Ϫ2.71 (m, 2 H, H1), 2.38Ϫ2.34 (m, 2 H, H2), 2.30 (s, 3 H,
NϪCH3) ppm. 13C NMR (CDCl3): δ ϭ 203.2 (d, JC,P ϭ 7.5 Hz,
CO ϫ 2), 138.8 (d, JC,P ϭ 46 Hz, C ϫ 2, Ph), 132.2 (d, JC,P
ϭ
9.6 Hz, CH ϫ 4, Ph), 129.4 (CH ϫ 2, Ph), 128.0 (d, JC,P ϭ 9.3 Hz,
CH ϫ 4, Ph), 103.5 (C, Cp), 88.7 (CH ϫ 2, Cp), 78.5 (CH ϫ 2,
Cp), 63.8 (CH2, C1), 62.9 (d, JC,P ϭ 52 Hz, CH2, PCH2), 45.9 (d,
JC,P ϭ 10.4 Hz, CH3, NϪCH3), 26.6 (CH2, C2) ppm. 31P NMR
(CDCl3): δ ϭ 26.0 (s) ppm. C23H23NO2PRe (562.62): calcd. C
49.10, H 4.12, N 2.49; found C 49.24, H 3.92, N 2.28.
a
ReϪCH2 ), 3.46 (d, J ϭ 1.7 Hz, 1 H, ReϪCH2b), 3.40 (s, 3 H,
NϪCH3), 2.21Ϫ2.15 (m, 2 H, H2Јs) ppm. 13C NMR (CD3CN):
δ ϭ 200.9 (CO), 196.8 (CO), 122.0 (C, Cp), 97.8 (CH, Cp), 92.9
(CH, Cp), 88.7 (CH, Cp), 84.6 (CH, Cp), 77.3 (CH2, C1), 58.4
(CH3), 30.7 (CH2, ReϪCH2), 22.4 (CH2, C2) ppm. C11H13INO2Re
(359.12): calcd. C 26.20, H 2.60, N 2.78; found C 26.04, H 2.75,
N 3.03.
Preparation of Complex 13: To a stirred solution of 10 (1.414 g,
2.66 mmol) in CH2Cl2 (35 mL) at 0 °C was added m-chloroperben-
zoic acid (0.67 g, 80%, 1.2 equiv.) in 3 portions over 5 min. The
initially colorless solution became yellow immediately. After stir-
ring for an additional 20 min, CH2Cl2 was evaporated. The residue
was dissolved in CH3OH (15 mL) and a solution of NaBPh4 (1.1 g)
in CH3OH (5 mL) was then added. The yellow solid was collected
Preparation of 9a: To a stirred suspension of 8 (0.149 g, 0.29 mmol)
in CH2Cl2 (10 mL) was added tert-butylamine (2 mL). The mixture
was stirred at room temperature for 17 h. The resultant yellow solu-
tion was concentrated and the residue was flash chromatographed
1672
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Eur. J. Inorg. Chem. 2004, 1668Ϫ1674

Selective Reaction of Aminorhenium Complexes
using a centrifuge and washed three times with CH3OH. The final suspension of 13 (342 mg, 0.4 mmol) in THF (6 mL) at 0 °C over
FULL PAPER
yellow solid was recrystallized from a solution of acetone and
1 min. After stirring for an additional 20 min, CH3I (0.4 mL) or
benzyl bromide (0.5 mL) was added to the resultant yellow-brown
solution. The cooling bath was removed and the solution was
methanol to give yellow crystalline 13 (1.377 g, 60%, yield). M.p.
1
190Ϫ196 °C. IR (acetone): ν˜ ϭ 1926 s cmϪ1. H NMR ([D6]ace-
tone): δ ϭ 8.00Ϫ7.55 (m, 10 H, Ph), 7.36Ϫ7.30 (m, 8 H, Ph), 6.91 stirred at room temperature for 1 h. The solution was concentrated
(t, J ϭ 7.3 Hz, 8 H, Ph), 6.67 (t, J ϭ 7.2 Hz, 4 H, Ph), 6.50 (dd, under reduced pressure and the residues were washed twice with
a
J ϭ 15.3, 6.0 Hz, 1 H, PCH2 ), 6.17Ϫ6.15 (m, 1 H, Cp), 5.76Ϫ5.67 methanol then twice with diethyl ether. The solids were then recrys-
(m, 3 H, Cp-H’s and PCH2b), 4.95Ϫ4.93 (m, 1 H, Cp), 4.06Ϫ4.39 tallized from a solution of acetone and hexane.
(m, 1 H, H1a), 3.95Ϫ3.85 (m, 1 H, H1b), 3.41 (s, 3 H, NϪCH3),
2.71Ϫ2.68 (m, 1 H, H2a), 2.50Ϫ2.45 (m, 1 H, H2b), Ϫ6.15 (d, J ϭ
14b: Orange crystals, 271 mg (78% yield). M.p. 210Ϫ215 °C (dec.).
41 Hz, 1 H, ReϪH) ppm. 31P NMR (CDCl3): δ ϭ Ϫ42.7 ppm.
C46H44BNOPRe (854.86): calcd. C 64.63, H 5.19, N 1.64; found C
64.50, H 5.12, N 1.80.
IR (CH3CN): ν˜ ϭ1918 s cmϪ1 1H NMR ([D6]acetone): δ ϭ
.
8.10Ϫ7.31 (m, 18 H, Ph), 6.91 (t, J ϭ 7.3 Hz, 8 H, Ph), 6.77 (t,
a
J ϭ 7.2 Hz, 4 H, Ph), 6.45 (dd, J ϭ 15.1, 5.8 Hz, 1 H, PCH2 ),
6.43Ϫ6.41 (m, 1 H, Cp), 6.34Ϫ6.32 (m, 1 H, Cp), 5.55 (dd, J ϭ
15.1, 6.5 Hz, 1 H, PCH2b), 5.25Ϫ5.23 (m, 1 H, Cp), 4.88Ϫ4.86 (m,
1 H, Cp), 4.09 (br. dd, J ϭ 12.1, 5.2 Hz, 1 H, H1a), 3.90 (td, J ϭ
12.1, 5.5 Hz, 1 H, H1b), 3.52 (s, 3 H, NϪCH3), 2.67 (ddd, J ϭ 14.4,
12.6, 5.2 Hz, 1 H, H2a), 2.37 (ddd, J ϭ 14.4, 5.4, 1.5 Hz, 1 H, H2b),
0.48 (d, J ϭ 12 Hz, 3 H, ReϪCH3) ppm. 31P NMR ([D6]acetone):
δ ϭ Ϫ36.6 ppm. C47H46BNOPRe (868.88): calcd. C 64.97, H 5.34,
N 1.61; found C 65.02, H 5.51, N 1.48.
Preparation of Complex 14a: To a stirred pale yellow solution of
13 (0.196 g, 0.23 mmol) in acetone (10 mL) at 0 °C was added N-
bromosuccinimide (62 mg, 1.5 equiv.). After stirring for 5 min, the
acetone was evaporated. The resultant solid was washed with di-
ethyl ether several times and recrystallized from a solution of ace-
tone and methanol to provide red crystals 168 mg (78% yield) of
14a. M.p. 199Ϫ210 °C (dec). IR (acetone): ν˜ ϭ 1953 s cmϪ1 1H
.
NMR (CD3CN): δ ϭ 7.99Ϫ6.82 (m, 30 H, Ph), 6.63Ϫ6.61 (m, 1
H, Cp), 6.41Ϫ6.39 (m, 1 H, Cp), 5.92 (dd, J ϭ 11.3, 4.2 Hz, 1 H,
14c: Orange crystals, 322 mg (85% yield). M.p. 165Ϫ170 °C (dec.).
a
PCH2 ), 5.65Ϫ5.63 (m, 1 H, Cp), 5.55Ϫ5.53 (m, 1 H, Cp), 5.48
IR (CH2Cl2): ν˜ ϭ1918 s cmϪ1 1H NMR ([D6]acetone): δ ϭ
.
(dd, J ϭ 11.3, 4.5 Hz, 1 H, PCH2b), 3.82Ϫ3.77 (m, 1 H, H1a),
3.62Ϫ3.56 (m, 1 H, H1b), 3.36 (s, 3 H, NϪCH3), 2.30Ϫ2.26 (m, 2
8.22Ϫ6.72 (m, 35 H, Ph), 6.55Ϫ6.53 (m, 1 H, Cp), 6.48 (dd, J ϭ
a
14.8, 5.6 Hz, 1 H, PCH2 ), 6.29Ϫ6.27 (m, 1 H, Cp), 5.59 (dd, J ϭ
H, H2Јs) ppm. 31P NMR ([D6]acetone):
δ ϭ Ϫ54.1 ppm.
14.8, 6.4 Hz, 1 H, PCH2b), 5.43Ϫ5.41 (m, 1 H, Cp), 4.10Ϫ4.06 (m,
1 H, H1a), 3.98Ϫ3.92 (m, 1 H, H1b), 3.65 (dd, J ϭ 9.8, 7.3 Hz, 1
H, benzylic-Ha), 3.49 (s, 3 H, NϪCH3), 3.39Ϫ3.37 (m, 1 H, Cp),
2.78 (dd, J ϭ 14, 9.8 Hz, 1 H, benzylic-Hb), 2.69Ϫ2.60 (m, 1 H,
C46H43BBrNOPRe (933.75): calcd. C 59.17, H 4.64, N 1.50; found
C 59.20, H 4.42, N 1.72.
General Procedure for the Preparation of 14b and 14c: A solution
nBuLi in hexane (1.6 , 0.31 mL, 1.2 equiv.) was added to a stirred H2a), 2.32Ϫ2.26 (m, 1 H, H2b) ppm. 31P NMR (CDCl3): δ ϭ
Table 1. Crystallographic data and structure refinements for 10, 13 and 15
Compound
10
13
15
Empirical formula
Formula mass
Crystal size (mm)
Color
C23H23NO2PRe
562.62
0.25 ϫ 0.31 ϫ 0.38
colorless
293
C46H43BNOPRe
853.84
0.29 ϫ 0.25 ϫ 0.17
yellow
C49H48BNOPRe
893.91
0.44 ϫ 0.22 ϫ 0.13
yellow
Temp. (K)
293
293
Crystal system
Space group
monoclinic
P21/c
9.396(2)
13.264(1)
17.399(3)
90
103.50(1)
90
2108.5(5)
4
1.772
1096
0.71069
59.331
monoclinic
P21
9.8352(9)
14.9626(8)
13.5028(14)
90
103.218(7)
90
1934.4(3)
2
1.466
857.81
0.71069
32.2
monoclinic
P21/c
17.6512(15)
12.0400(9)
18.8272(19)
90
90.968(8)
90
4000.6(6)
4
1.484
1803.61
0.71069
31.2
˚
a (A)
˚
b (A)
˚
c (A)
α (°)
β (°)
γ (°)
3
˚
V (A )
Z
Dcalcd. (g cmϪ3
F(000)
)
˚
λ (Mo-Kα) (A)
µ (Mo-Kα) (cmϪ1
)
Tmin.,max.
0.758, 1.00
2.06Ϫ8.24
0.70 ϩ 0.35tanθ
50
(Ϫ11;10), (0;15), (0;20)
3698
2893
254
0.025; 0.028
1.31
0.910; Ϫ0.690
0.391, 0.500
1.92Ϫ13.5
0.76 ϩ 0.39tanθ
50
(Ϫ11;11), (Ϫ17;0), (Ϫ16;16)
3534
3252
459
0.323, 0.500
1.22Ϫ6.74
0.60 ϩ 0.35tanθ
50
(Ϫ20;20), (0;14), (0;21)
5814
4102
488
0.031; 0.035
1.51
0.890; Ϫ0.980
Scan rate (°·minϪ1
)
θ/2θ scan width (°)
2θmax (°)
h,k,l range
Unique reflns.
Obsd. reflns. [I Ͼ 2.0σ(I)]
Refined parameters
RF;Rw
GOF
(∆ρ)max.,min. (e·A
0.023; 0.027
1.44
0.910; Ϫ0.530
Ϫ3
˚
)
Eur. J. Inorg. Chem. 2004, 1668Ϫ1674
www.eurjic.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1673

T.-F. Wang, T.-C. Wang, Y.-S. Wen
FULL PAPER
Ϫ36.5 ppm. C53H50BNOPRe (944.98): calcd. C 67.36, H 5.33, N
1.48; found C 67.11, H 5.35, N 1.62.
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were washed twice with methanol. The solid obtained was recrys-
tallized from a solution of CH2Cl2 (3 mL) and CH3OH (5 mL) at
room temperature. Pale yellow platelet crystals of the η3-allyl com-
plex 15 were collected (137 mg, 91% yield). M.p. 220Ϫ225 °C
(dec.). IR (CH2Cl2): ν˜ ϭ1960 s cmϪ1. 1H NMR ([D6]acetone): δ ϭ
7.61Ϫ7.31 (m, 18 H, Ph), 6.91 (t, J ϭ 7.4 Hz, 8 H, Ph), 6.76 (t,
J ϭ 7.2 Hz, 4 H, Ph), 6.40 (br., 1 H, Cp), 6.07 (br., 1 H, Cp), 5.90
(br., 1 H, Cp), 5.83 (br., 1 H, Cp), 4.20 (d, J ϭ 14.5 Hz, 1 H,
[2d]
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a
PCH2 ), 4.00 (dd, J ϭ 14.5, 1.5 Hz, 1 H, PCH2b), 3.14Ϫ2.79 (m, 9
H), 1.98 (s, 3 H, NϪCH3) ppm. 31P NMR ([D6]acetone): δ ϭ
10.2 ppm. C49H48BNOPRe (894.92): calcd. C 65.76, H 5.41, N
1.56; found C 65.58, H 5.70, N 1.62.
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[7a] A part of the results has been presented at the 220th Amer-
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tained from a solution of CH2Cl2 and hexane, 13 from a solution
of acetone and methanol, and 15 from a solution of CH2Cl2 and
methanol at room temperature, respectively. Diffraction measure-
ments were made on an EnrafϪNonius CAD-4 automated dif-
fractometer using graphite-monochromated Mo-Kα radiation (λ ϭ
August 20Ϫ24, 2000, INORϪ241. Recent publications con-
[7b]
cerning Cp-N-X tridentate complexes:
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˚
0.71069 A) with the θϪ2θ scan mode. The unit cells were deter-
[7d]
19, 4066Ϫ4076.
K. C. Hultzsch, P. Voth, K. Beckerle, T. P.
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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
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the systematic absences observed during data collection. All data
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solved by direct methods and refined by a full-matrix least-squares
routine[13] with anisotropic thermal parameters for all non-hydro-
gen atoms. The structures were refined by minimizing Σw|Fo Ϫ Fc|2,
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drogens were included in the structure factor calculations in their
expected positions on the basis of idealized bonding geometries
but were not refined in the least-squares procedure. The final cell
parameters and data collection parameters are listed in Table 1.
CCDC-219541 (for 10), -219542 (for 13) and -219543 (for 15) con-
tain the supplementary crystallographic data for this paper. Copies
of the data can be obtained free of charge on application to CCDC,
12 Union Road, Cambridge CB2 1EZ, UK [Fax: (internat.)
ϩ 44-1223-336-033; E-mail: deposit@ccdc.cam.ac.uk].
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T. F. Wang, C. Y. Lai, C. C. Hwu, Y. S. Wen, Organometallics
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[11]
[12]
[13]
Acknowledgments
We are grateful to the National Science Council of Taiwan for fin-
ancial support.
Received September 14, 2003
Early View Article
Published Online March 9, 2004
1674
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Eur. J. Inorg. Chem. 2004, 1668Ϫ1674