Synthesis of vanadium(v) hydrazido complexes with tris(2-hydroxyphenyl) amine ligands

Article abstract of DOI:10.1039/c3dt50533b

The reaction of the oxidovanadium(v) complexes with N,N-dimethylhydrazine was demonstrated to afford the corresponding vanadium(v) dimethylhydrazido complexes. The substituent at the 3-position of the tris(2-hydroxyphenyl)amine ligand was found to influen

Full text of DOI:10.1039/c3dt50533b

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Synthesis of vanadium(V) hydrazido complexes with
tris(2-hydroxyphenyl)amine ligands†
Cite this: Dalton Trans., 2013, 42, 11824
Toshiyuki Moriuchi,*a Kousuke Ikeuchia and Toshikazu Hirao*a,b
The reaction of the oxidovanadium(V) complexes with N,N-dimethylhydrazine was demonstrated to
afford the corresponding vanadium(V) dimethylhydrazido complexes. The substituent at the 3-position of
the tris(2-hydroxyphenyl)amine ligand was found to influence the electronic environment of the
vanadium center. The crystal structure of the non-substituted vanadium(V) dimethylhydrazido complex
exhibited a distorted trigonal bipyramidal geometry with phenolate oxygen atoms in equatorial positions
and the near-linear V(1)–N(2)–N(3) angle. The vanadium(V) diphenylhydrazido complexes could be
obtained by the reaction of the oxidovanadium(V) complexes with N,N-diphenylhydrazine. A distorted
trigonal bipyramidal geometry with phenolate oxygen atoms in equatorial positions was also observed
in the crystal structure of the non-substituted vanadium(V) diphenylhydrazido complex.
Received 27th February 2013,
Accepted 11th April 2013
DOI: 10.1039/c3dt50533b
www.rsc.org/dalton
of the tris(2-hydroxyphenyl)amine ligand on the vanadium
center.
Introduction
Much attention has been devoted to metal hydrazido com-
pounds due to their intermediacy in dinitrogen activation.1 In
particular, most of the studies have focused on molybdenum
hydrazido compounds because molybdenum is present in an
active site of nitrogenases.2 On the other hand, the biochemi-
cal roles of vanadium have gained growing interest which is
related to the insulinomimetic ability of vanadium com-
pounds3 and vanadium-dependent haloperoxidases.4 Although
vanadium is known to be an essential constituent in certain
nitrogenases,1a–d,5 vanadium hydrazido complexes have
attracted less attention.6 We have already demonstrated that
the substituents in the para position on the benzene rings of
(arylimido)vanadium(V) complexes affect the nature of the
imido bonds through π conjugation.7 The coordination from
the apical nitrogen in the (arylimido)vanadium(V) triethanol-
aminates was also performed to influence the electron donation
from the imido nitrogen to vanadium metal.8 The substituent
effect of the basal ligand in the vanadium(V) hydrazido
complex has not been investigated so far. From these points of
view, we herein report the synthesis of the vanadium(V) hydra-
zido complexes with tris(2-hydroxyphenyl)amine ligands to
reveal the influence of the apical nitrogen and the substituent
Results and discussion
The substituted tris(2-hydroxyphenyl)amines 2 were prepared
by the deprotection of methoxy groups of the ligand precursors
1, which were synthesized by Ullmann-type reaction of the sub-
stituted 2-methoxyaniline with 1-iodo-2-methoxybenzene. The
reaction of VO(OiPr)3 with the substituted tris(2-hydroxyphe-
nyl)amines
2 in dichloromethane at room temperature
afforded the corresponding oxidovanadium(V) complexes 3 as
shown in Scheme 1.9 The vanadium(V) dimethylhydrazido
complexes 4 with the tris(2-hydroxyphenyl)amine ligand could
be obtained by the treatment of the corresponding oxidovana-
dium(V) complexes 3 with N,N-dimethylhydrazine in dichloro-
methane at room temperature. 51V NMR measurements were
performed in order to clarify the substituent effect on the elec-
tronic environment of the vanadium species. The 51V chemical
shift of the non-substituted vanadium(V) dimethylhydrazido
complex 4b was detected at 335 ppm. In the 51V NMR spec-
trum of 4a with the electron-donating substituent, the
51V chemical shift was observed at 328 ppm. In contrast, the
electron-withdrawing substituent caused the 51V chemical
shift to higher frequency (4c: 381 ppm; 4d: 378 ppm). The sub-
stituent at the 3-position of the tris(2-hydroxyphenyl)amine
ligand was found to influence the electron density of the
vanadium center directly. A similar substituent effect was
observed in the vanadium(V) diphenylhydrazido complexes 5
(5a: 164 ppm; 5b: 178 ppm; 5c: 206 ppm; 5d: 209 ppm),
which were prepared by the reaction of the corresponding
aDepartment of Applied Chemistry, Graduate School of Engineering,
Osaka University, Yamada-oka, Suita, Osaka 565-0871, Japan.
E-mail: moriuchi@chem.eng.osaka-u.ac.jp, hirao@chem.eng.osaka-u.ac.jp;
Fax: +81-6-6879-7415; Tel: +81-6-6879-7413
bJST, ACT-C, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
†CCDC 925607–925609. For crystallographic data in CIF or other electronic
format see DOI: 10.1039/c3dt50533b
11824 | Dalton Trans., 2013, 42, 11824–11830
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Scheme 1 Synthesis of the vanadium(V) hydrazido complexes 4 and 5.
Table 1 Crystallographic data for 4b, 4d-DMH-4d, and 5b
Table 2 Selected bond lengths (Å) and angles (°) for 4ba and 5ba
4b
4d-DMH-4d
5b
4b
5b
Formula
Formula weight
Crystal system
Space group
a (Å)
b (Å)
c (Å)
C20H18N3O3V
399.31
C42H42N8O6F2V2
894.72
C30H22N3O3V
523.45
Monoclinic
Bond lengths
V1–N1
V1–N2
2.2751(18)
1.6891(19)
1.8685(16)
1.8536(16)
1.8538(15)
1.304(3)
2.2782(18)
1.6837(19)
1.8572(16)
1.8548(16)
1.8574(16)
1.312(3)
2.255(4)
1.683(4)
1.841 (3)
1.845(3)
1.848(3)
1.315(5)
2.268(4)
1.692(4)
1.830(3)
1.852(3)
1.836(3)
1.316(5)
Monoclinic
P21/n (no. 14)
16.2235(5)
11.8240(3)
18.6632(5)
96.4640(10)
3557.32(18)
8
1.491
−170
0.71075
0.046
0.117
Monoclinic
P21 (no.4)
9.3304(11)
18.403(2)
12.1985(14)
102.631(3)
2043.9(4)
2
1.454
−150
0.71075
0.074
P21/n (no. 14) V1–O1
20.7200(15)
9.1557(6)
25.6467(18)
99.487(2)
4798.8(6)
8
1.449
−150
0.71075
0.066
V1–O2
V1–O3
N2–N3
β (°)
Bond angles
V1–N2–N3
N1–V1–N2
N1–V1–O1
N1–V1–O2
N1–V1–O3
N2–V1–O1
N2–V1–O2
N2–V1–O3
O1–V1–O2
O1–V1–O3
O2–V1–O3
V (Å3)
176.60(17)
178.88(8)
81.03(7)
80.92(7)
81.02(6)
99.00(8)
98.09(8)
99.95(8)
117.35(7)
116.25(7)
119.17(7)
173.11(16)
177.02(8)
81.18(7)
80.40(7)
81.35(6)
96.69(8)
99.04(8)
101.42(8)
121.21(7)
111.48(8)
120.00(7)
173.7(4)
161.8(3)
Z
175.63(18)
81.08(14)
80.18(14)
81.52(14)
102.33(18)
95.59(17)
99.42(17)
123.79(16)
113.74(15)
115.06(16)
174.57(17)
80.12(14)
80.95(14)
81.81(14)
95.39(17)
98.56(17)
103.30(17)
117.08(15)
123.42(16)
112.16(16)
Dcalcd (g cm−3
T (°C)
)
λ(Mo Kα) (Å)
a
R1
b
wR2
0.180
0.177
a R1 = Σ||Fo| − |Fc||/Σ|Fo|. b wR2 = [Σw(Fo2| − |Fc2|)2/Σw(Fo2)2]1/2
.
a Two independent molecules exist in the asymmetric unit.
oxidovanadium(V) complexes 3 with N,N-diphenylhydrazine.
51V chemical shifts of 5 were observed at the lower frequency
compared to those of 4. The electron-withdrawing diphenyl
substituent, in which the nitrogen atom of the imido bond
becomes more electronegative to increase 51V nuclear shield-
ing, is considered to cause the 51V chemical shift to the lower
frequency. These results are consistent with those of the (aryl-
imido)vanadium(V) trichlorides reported.7,8,10 Structural charac-
terization of the vanadium(V) dimethylhydrazido complex 4b
was demonstrated by single-crystal X-ray structure determi-
nation to elucidate the influence of the coordination from the
apical nitrogen on the vanadium center in the hydrazido struc-
ture (Table 1). The important bond lengths and angles are
listed in Table 2. The crystal structure of 4b, in which two inde-
pendent molecules exist in the asymmetric unit, exhibited the
near-linear V(1)–N(2)–N(3) angles of 176.60(17) and 173.11(16)°
with the V(1)–N(2) distances of 1.6891(19) and 1.6837(19)
Å as shown in Fig. 1, suggesting the high participation of an
sp-hybridized character in the nitrogen of the imido bond. The
geometry at the metal center is a distorted trigonal bipyrami-
dal geometry with the phenolate oxygen atoms in equatorial
Fig. 1 Molecular structure of 4b.
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Table 3 Selected bond lengths (Å) and angles (°) for 4d-OMH-4d
Bond lengths
V1–N1
V1–N2
V1–N7
V1–O1
V1–O2
V1–O3
N2–N3
2.295(7)
1.663(7)
2.349(7)
1.903(6)
1.902(6)
1.862(6)
1.315(10)
1.512(9)
V2–N4
V2–N5
V2–N8
V2–O4
V2–O5
V2–O6
N5–N6
2.270(7)
1.690(7)
2.245(7)
1.913(6)
1.895(6)
1.910(6)
1.300(10)
N7–N8
Bond angles
V1–N2–N3
V1–N7–N8
N1–V1–N2
N1–V1–N7
N1–V1–O1
N1–V1–O2
N1–V1–O3
N2–V1–N7
N2–V1–O1
N2–V1–O2
N2–V1–O3
N7–V1–O1
N7–V1–O2
N7–V1–O3
O1–V1–O2
O1–V1–O3
O2–V1–O3
171.8(7)
106.9(4)
172.0(3)
101.9(2)
79.8(3)
77.7(2)
79.5(2)
85.6(3)
92.6(3)
101.0(3)
104.6(3)
178.2(3)
81.0(2)
82.3(3)
98.9(3)
98.6(3)
148.2(2)
V2–N5–N6
V2–N8–N7
N4–V2–N5
N4–V2–N8
N4–V2–O4
N4–V2–O5
N4–V2–O6
N5–V2–N8
N5–V2–O4
N5–V2–O5
N5–V2–O6
N8–V2–O4
N8–V2–Q5
N8–V2–O6
04–V2–O5
04–V2–O6
05–V2–O6
174.0(7)
133.4(5)
173.6(3)
90.1(2)
79.5(2)
77.6(2)
80.1(2)
96.3(3)
102.3(3)
102.4(3)
93.6(3)
76.9(3)
85.3(3)
168.6(3)
150.9(2)
95.4(3)
98.2(2)
Fig. 2 Molecular structure of 4d-DMH-4d.
positions. The vanadium atom is pulled out of the plane
formed by the phenolate oxygen atoms in the direction of the
hydrazido nitrogen. Three equatorial vanadium–oxygen bond
distances are statistically identical. The V(1)–N(2) distances of
4b with the coordination from the apical nitrogen is longer
than that of the vanadium(V) dimethylhydrazido complex,
shown in Table 2. As 5b crystallized in the space group P21/n
with Z = 8, two independent molecules exist in the asymmetric
unit. The metal centers are distorted trigonal bipyramidal ge-
ometries with phenolate oxygen atoms in equatorial positions
as shown in Fig. 3. One molecule of 5b shows the V(1)–N(2)–
N(3) angle of 173.7(4)° with the V(1)–N(2) distance of 1.683(4) Å,
indicating the high participation of an sp-hybridized character
in the nitrogen of the imido bond. This hydrazido structure
is almost similar to that of 4b. The V(1)–N(2)–N(3) angle of
161.8(3)° with the V(1)–N(2) distance of 1.692(4) Å based on
some contribution of an sp2-hybridized character in the nitro-
gen of the imido bond was observed in the crystal structure of
another molecule as depicted in Fig. 3.
i
[V(NNMe2)(OC6H3 Pr2-2,6)3], with tetrahedral geometry at the
vanadium center (V(1)–N(2), 1.653(3) Å),6d probably due to the
coordination of the apical nitrogen. The electron donation
from N(2) to vanadium metal might be weakened to some
extent.
The N,N-dimethylhydrazine-bridged dinuclear vanadium(V)
hydrazido complex 4d-DMH-4d could be obtained by recrystal-
lization of 4d in the presence of N,N-dimethylhydrazine. The
structure of 4d-DMH-4d was confirmed by single-crystal X-ray
structure determination. Table 3 shows the selected bond
lengths and angles. The solid-state molecular structure reveals
that two 4d units are bridged by N,N-dimethylhydrazine to
form the 2 : 1 complex in anti-configuration as depicted in
Fig. 2. The 3-fluoro group on the benzene ring might decrease
the electron density of the vanadium center, resulting in the
coordination of N,N-dimethylhydrazine to the vanadium
center to form a hexacoordinate geometry. This hydrazido
complex 4d-DMH-4d showed the near-linear V(1)–N(2)–N(3)
angles of 171.8(7) and 174.0(7)° with the V(1)–N(2) distances of
1.663(7) and 1.690(7) Å, respectively. The V(1)–N(7) distance
(2.349(7) Å) is longer than that of the V(2)–N(8) bond (2.245(7)
Å) probably due to the steric hindrance of the dimethyl
moieties.
Conclusions
In conclusion, the vanadium(V) hydrazido complexes with the
tris(2-hydroxyphenyl)amine ligand were demonstrated to
reveal the influence of the coordination from the apical nitro-
gen and the substituent of the tris(2-hydroxyphenyl)amine
ligand on the vanadium center in solid and/or solution states.
The coordination of the apical nitrogen to the vanadium
center was performed to weaken the V–N multiple bond
through the coordination from the apical nitrogen. The substi-
tuent at the 3-position of the tris(2-hydroxyphenyl)amine
ligand was found to influence the electronic environment of
the vanadium center directly. Further characterization of the
hydrazido structures and the application of the vanadium(V)
hydrazido complexes for catalysis are now in progress.
The structure of the vanadium(V) diphenylhydrazido
complex 5b was also confirmed by single-crystal X-ray structure
determination. The important bond lengths and angles are
11826 | Dalton Trans., 2013, 42, 11824–11830
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external standard. Mass spectra were run on a JEOL JMS
DX-303 spectrometer.
Synthesis of 2-methoxy-3-methyl-N,N-bis(2-methoxyphenyl)-
aniline (1a)
A mixture of 2-methoxy-3-methylaniline (549 mg, 4.0 mmol),
1-iodo-2-methoxybenzene (1.56 mL, 12.0 mmol), Cu (890 mg,
14.0 mmol), K2CO3 (2.76 g, 20.0 mmol) and 18-crown-6
(137 mg, 0.52 mmol) in 1,2-dichlorobenzene (50 mL) was
refluxed under Ar for 24 h. After cooling, the insoluble in-
organic material was filtered off. The solvent of the resulting
filtrate was removed under reduced pressure and the residue
was chromatographed on a silica-gel column (eluent, hexane–
dichloromethane 1 : 1) to give the desired product 1a (572 mg,
1.64 mmol) as a white solid.
1a: yield 41%; mp 80–82 °C; 1H NMR (400 MHz, CDCl3)
δ 7.04 (td, 2H, J = 7.3, 1.8 Hz), 6.89–6.78 (m, 8H), 6.65 (dd, 1H,
J = 7.3, 2.2 Hz), 3.63 (s, 3H), 3.56 (s, 6H), 2.22 (s, 3H); 13C NMR
(100 MHz, CDCl3) 153.9, 151.7, 141.7, 137.8, 132.1, 125.5,
125.2, 124.2, 123.4, 122.3, 121.0, 113.1, 58.8, 56.0, 16.4 ppm;
HRMS (EI) m/z Calcd for C22H23N1O3 (M+), 349.1678; Found,
349.1677.
Synthesis of 3-bromo-2-methoxy-N,N-bis(2-methoxyphenyl)-
aniline (1c)
A mixture of 3-bromo-2-methoxyaniline (1.62 g, 8.0 mmol),
1-iodo-2-methoxybenzene (3.12 mL, 24.0 mmol), Cu (1.78 g,
28.0 mmol), K2CO3 (5.53 g, 40.0 mmol) and 18-crown-6
(275 mg, 1.04 mmol) in 1,2-dichlorobenzene (80 mL) was
refluxed under Ar for 24 h. After cooling, the insoluble in-
organic material was filtered off. The solvent of the resulting
filtrate was removed under reduced pressure and the residue
was chromatographed on a silica-gel column (eluent, hexane–
ethyl acetate 5 : 1) to give the desired product 1c (1.39 g,
3.36 mmol) as a white solid.
1c: yield 42%; mp 94–95 °C; 1H NMR (400 MHz, CDCl3)
δ 7.15 (dd, 1H, J = 7.6, 1.8 Hz), 7.04 (td, 2H, J = 7.8, 2.0 Hz),
6.89–6.81 (m, 6H), 6.74 (t, 1H, J = 7.6 Hz), 6.71 (dd, 1H, J = 8.0,
2.0 Hz), 3.65 (s, 3H), 3.57 (s, 6H); 13C NMR (100 MHz, CDCl3)
154.0, 150.1, 143.4, 137.1, 126.6, 126.0, 124.8, 124.6, 123.3,
121.1, 118.2, 113.0, 59.3, 55.9 ppm; HRMS (FAB) m/z Calcd for
C21H20Br1N1O3 (M+), 413.0627; Found, 413.0631.
Fig. 3 Molecular structures of two independent molecules in the asymmetric
unit of 5b.
Synthesis of 3-fluoro-2-methoxy-N,N-bis(2-methoxyphenyl)-
aniline (1d)
Experimental
General methods
A mixture of 3-fluoro-2-methoxyaniline (602 μL, 5.0 mmol),
All reagents and solvents were purchased from commercial 1-iodo-2-methoxybenzene (1.95 mL, 15.0 mmol), Cu (1.05 g,
sources and were further purified by the standard methods, if 16.5 mmol), K2CO3 (3.46 g, 25.0 mmol) and 18-crown-6
necessary. All manipulations were carried out under nitrogen. (172 mg, 0.65 mmol) in 1,2-dichlorobenzene (60 mL) was
Melting points were determined on a Yanagimoto Micromelt- refluxed under Ar for 24 h. After cooling, the insoluble in-
ing Point Apparatus and were uncorrected. 1H NMR and 13C organic material was filtered off. The solvent of the resulting
NMR spectra were recorded on a JEOL JNM-ECP 400 (400 and filtrate was removed under reduced pressure and the residue
100 MHz, respectively) spectrometer with tetramethylsilane as was chromatographed on a silica-gel column (eluent, hexane–
an internal standard. 51V NMR spectra were obtained with a dichloromethane 1 : 1) to give the desired product 1d (1.3 g,
JEOL JNM-ECP 400 (105 MHz) spectrometer with VOCl3 as an 3.7 mmol) as a white solid.
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1
1d: yield 74%; mp 107–108 °C; H NMR (400 MHz, CDCl3) After evaporation of the solution, the desired product 2d was
δ 7.06 (td, 2H, J = 7.8, 1.8 Hz), 6.9–6.7 (m, 8H), 6.56 (dt, 1H, isolated as a white solid (168 mg, 0.54 mmol) by reprecipita-
J = 8.2, 1.8 Hz), 3.59 (s, 6H), 3.52 (s, 3H); 13C NMR (100 MHz, tion from ethyl acetate and hexane.
1
3
1
CDCl3) 156.8 (d, JF–C = 244.4 Hz), 154.0, 143.5 (d, JF–C
=
2d: yield 54%; mp 138–139 °C; H NMR (400 MHz, CDCl3)
2
3.8 Hz), 141.1 (d, JF–C = 12.5 Hz) 137.4, 125.8, 124.7, 122.7 δ 7. 11 (td, 2H, J = 7.6, 1.6 Hz), 6.99–6.85 (m, 7H), 6.78 (td, 1H
(d, JF–C = 9.6 Hz), 121.1, 119.3, 113.1, 110.5 (2JF–C = 19.2 Hz), J = 8.2, 6.0 Hz), 6.72 (dt, 1H, J = 8.2, 1.4 Hz), 5.56 (s, 2H), 5.33
3
60.1 (d, JF–C = 3.8 Hz), 56.0 ppm; HRMS (EI) m/z Calcd for (s, 1H); 13C NMR (100 MHz, CDCl3) 152.2 (d, JF–C = 239.6 Hz),
4
1
C21H20F1N1O3 (M+), 353.1427; Found, 353.1429.
150.6, 138.3 (d, 2JF–C = 15.3 Hz), 135.8 (d, 3JF–C = 2.9 Hz), 133.4,
127.1, 126.2, 121.4, 120.4 (d, 3JF–C = 8.6 Hz), 120.2, 117.1, 112.4
(2JF–C = 18.2 Hz) ppm; HRMS (EI) m/z Calcd for C18H14F1N1O3
(M+), 311.0958; Found, 311.0954.
Synthesis of 2-hydroxy-3-methyl-N,N-bis(2-hydroxyphenyl)-
aniline (2a)
To a dichloromethane (15 mL) solution of 2-methoxy-3-methyl-
N,N-bis(2-methoxyphenyl)aniline (1a) (349 mg, 1.0 mmol) was
added a 1 M BBr3 in dichloromethane (3.0 mL, 3.0 mmol)
Synthesis of oxidovanadium(V) complex 3a
A
mixture of the tris(2-hydroxyphenyl)amine ligand 2a
solution under Ar at −78 °C. The resulting mixture was stirred (154 mg, 0.50 mmol) and VO(OiPr)3 (118 μL, 0.50 mmol) was
at −78 °C for a few minutes. The mixture was allowed to warm stirred in dichloromethane (15 mL) under Ar at room tempera-
to room temperature and was stirred for 3 h. The resulting ture for 3 h. After evaporation of the solution, the oxidovana-
mixture was diluted with ethyl acetate and washed with water. dium(V) complex 3a was isolated as a blue-purple solid
After evaporation of the solution, the desired product 2a was (122 mg, 0.33 mmol) by reprecipitation from dichloromethane
isolated as a white solid (239 mg, 0.78 mmol) by reprecipita- and hexane.
tion from ethyl acetate and hexane.
3a: yield 66%; 1H NMR (400 MHz, CDCl3) δ 7.72 (dd, 2H,
1
2a: yield 78%; mp 120–121 °C; H NMR (400 MHz, CDCl3) J = 8.0, 1.4 Hz), 7.56 (d, 1H, J = 8.2 Hz), 7.22 (t, 2H, J = 7.8 Hz),
δ 7.11 (td, 2H, J = 8.0, 1.4 Hz), 7.01–6.77 (m, 9H), 5.33 (s, 1H), 7.08 (d, 1H, J = 7.3 Hz), 6.93 (t, 2H, J = 7.8 Hz), 6.85 (t, 1H,
5.15 (s, 2H), 2.24 (s, 3H); 13C NMR (100 MHz, CDCl3) 150.1, J = 7.8 Hz), 6.59 (d, 2H, J = 7.8 Hz), 2.18 (s, 3H); 13C NMR
148.6, 133.5, 132.8, 128.6, 126.4, 125.5, 123.3, 121.7, 120.8, (100 MHz, CDCl3) 164.2, 162.7, 140.8, 140.7, 131.8, 130.4,
117.4, 16.1 ppm; HRMS (EI) m/z Calcd for C19H17N1O3 (M+), 127.5, 126.1, 124.8, 123.9, 123.7, 115.7, 16.7 ppm; 51V NMR
307.1208; Found, 307.1210.
(105 MHz, CDCl3) −292 ppm; HRMS (FAB) m/z Calcd for
C19H14N1O4V1 (M+), 371.0362; Found, 371.0362.
Synthesis of 3-bromo-2-hydroxy-N,N-bis(2-hydroxyphenyl)-
aniline (2c)
Synthesis of oxidovanadium(V) complex 3c
To a dichloromethane (15 mL) solution of 3-bromo-2-methoxy-
A mixture of the tris(2-hydroxyphenyl)amine ligand 2c
N,N-bis(2-methoxyphenyl)aniline (1c) (207 mg, 0.5 mmol) was (186 mg, 0.50 mmol) and VO(OiPr)3 (118 μL, 0.50 mmol) was
added a 1 M BBr3 in dichloromethane (2.0 mL, 2.0 mmol) stirred in dichloromethane (15 mL) under Ar at room tempera-
solution under Ar at room temperature. The resulting mixture ture for 3 h. After evaporation of the solution, the oxidovana-
was stirred at room temperature for 3 h. The resulting mixture dium(V) complex 3c was isolated as a blue-green solid (218 mg,
was diluted with ethyl acetate and washed with water. After 0.50 mmol) by reprecipitation from dichloromethane and
evaporation of the solution, the desired product 2c was iso- hexane.
1
lated as a white solid (80 mg, 0.21 mmol) by reprecipitation
3c: yield 100%; H NMR (400 MHz, CDCl3) δ 7.66 (m, 3H),
7.44 (dd, 1H, J = 8.2, 1.4 Hz), 7.23 (td, 2H, J = 1.8, 8.2 Hz), 6.93
from ethyl acetate and hexane.
1
2c: yield 43%; mp 138–139 °C; H NMR (400 MHz, CDCl3) (td, 2H, J = 7.8, 1.4 Hz), 6.80 (t, 1H, J = 8.2 Hz), 6.58 (dd, 2H,
δ 7.29 (dd, 1H, J = 8.2, 1.4 Hz), 7.12 (td, 2H, J = 8.0, 1.4 Hz), J = 8.0, 1.2 Hz); 13C NMR (100 MHz, CDCl3) 164.2, 140.9, 140.4,
6.98–6.85 (m, 7H), 6.72 (t, 1H J = 7.8 Hz) 5.52 (s, 1H), 5.47 137.5, 133.9, 130.6, 127.3, 127.1, 124.4, 124.2, 115.7 ppm;
(s, 2H); 13C NMR (100 MHz, CDCl3) 150.7, 147.0, 135.0, 133.5, 51V NMR (105 MHz, CDCl3) −299 ppm; HRMS (FAB) m/z Calcd
128.8, 127.1, 126.2, 124.7, 121.9, 121.3, 117.0 ppm; HRMS for C18H11Br1N1O4V1 (M+), 434.9311; Found, 434.9314.
(FAB) m/z Calcd for C18H14Br1N1O3 (M+), 371.0157; Found,
Synthesis of oxidovanadium(V) complex 3d
371.0168.
A
mixture of the tris(2-hydroxyphenyl)amine ligand 2d
Synthesis of 3-fluoro-2-hydroxy-N,N-bis(2-hydroxyphenyl)-
aniline (2d)
(156 mg, 0.50 mmol) and VO(OiPr)3 (118 μL, 0.50 mmol) was
stirred in dichloromethane (15 mL) under Ar at room tempera-
To a dichloromethane (15 mL) solution of 3-fluoro-2-methoxy- ture for 3 h. After evaporation of the solution, the oxidovana-
N,N-bis(2-methoxyphenyl)aniline (1d) (353 mg, 1.0 mmol) was dium(V) complex 3d was isolated as a blue-purple solid
added a 1 M BBr3 in dichloromethane (3.0 mL, 3.0 mmol) (184 mg, 0.49 mmol) by reprecipitation from dichloromethane
solution under Ar at −78 °C. The resulting mixture was stirred and hexane.
1
at −78 °C for a few minutes. The mixture was allowed to warm
3d: yield 98%; H NMR (400 MHz, CDCl3) δ 7.68 (dd, 2H,
to room temperature and was stirred for 3 h. The resulting J = 8.0, 1.4 Hz), 7.50 (d, 1H, J = 7.8 Hz), 7.21 (t, 2H, J = 8.7 Hz),
mixture was diluted with ethyl acetate and washed with water. 6.99 (t, 1H J = 8.7 Hz), 6.92 (td, 2H, J = 8.7 Hz), 6.85 (td, 1H,
11828 | Dalton Trans., 2013, 42, 11824–11830
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J = 8.2, 5.5 Hz), 6.59 (d, 2H, J = 8.2 Hz); 13C NMR (100 MHz, pressure. The resulting red-purple solid was washed with
2
1
CDCl3) 164.3, 152.5 (d, JF–C = 11.5 Hz), 146.5 (d, JF–C
=
=
hexane to give the desired vanadium(V) diphenylhydrazido
complex 5.
3
251.1 Hz), 141.2, 139.7, 130.2, 127.1, 124.2, 123.0 (d, JF–C
3
2
7.7 Hz), 122.4 (d, JF–C = 3.8 Hz), 117.1 (d, JF–C = 17.3 Hz),
5a: yield 68%; 1H NMR (400 MHz, CDCl3) δ 7.75 (dd, 4H,
115.4 ppm; 51V NMR (105 MHz, CDCl3) −304 ppm; HRMS J = 8.0, 0.8 Hz), 7.66 (dd, 2H, J = 7.6, 1.2 Hz), 7.52 (d, 1H,
(FAB) m/z Calcd for C18H11F1N1O4V1 (M+), 375.0112; Found, J = 6.8 Hz), 7.50 (t, 4H, J = 7.6 Hz), 7.18 (td, 2H, J = 8.4, 2.0 Hz),
375.0112.
7.08 (d, 1H, J = 7.2 Hz), 6.82 (td, 2H, J = 8.0, 1.2 Hz), 6.76
(t, 1H, J = 7.6 Hz), 6.72 (dd, 2H, J = 8.4, 1.6 Hz); 13C NMR
(100 MHz, CDCl3) 164.1, 149.4, 141.3, 137.8, 131.1, 130.1,
Synthesis of vanadium(V) dimethylhydrazido complexes 4a–d
A mixture of the corresponding oxidovanadium(V) complex 3 129.5, 129.4, 129.2, 126.8, 126.2, 123.6, 122.1, 120.9, 120.7,
(0.10 mmol), N,N-dimethylhydrazine (15 μL, 0.20 mmol) and a 120.1, 119.6, 118.0, 117.1, 16.2 ppm; 51V NMR (105 MHz,
small amount of MS4A (4 Å molecular sieves) was stirred in CDCl3) 164 ppm; HRMS (FAB) m/z Calcd for C31H24N3O3V1
dichloromethane (10 mL) under an atmosphere of nitrogen in (M+), 537.1257; Found, 537.1256.
a drybox at room temperature for 2 h. The resulting solution
5b: yield 68%; 1H NMR (400 MHz, CDCl3) δ 7.71 (dd, 4H,
was filtered off, and the filtrate was evaporated under reduced J = 8.7, 0.9 Hz), 7.66 (dd, 3H, J = 8.0, 1.4 Hz), 7.50 (t, 4H,
pressure. The resulting red-brown solid was washed with J = 8.7 Hz), 7.31–7.15 (m, 5H), 7.17 (td, 3H, J = 8.2, 1.4 Hz),
hexane to give the desired vanadium(V) dimethylhydrazido 6.83 (td, 3H, J = 7.8, 1.4 Hz), 6.73 (dd, 3H, J = 8.2, 1.4 Hz);
complex 4.
13C NMR (100 MHz, CDCl3) 117.2, 119.6, 120.1, 121.1, 126.2,
4a: yield 56%; 1H NMR (400 MHz, CDCl3) δ 7.57 (dd, 2H, 126.9, 129.2, 129.4, 130.2, 137.8, 141.2, 164.2 ppm; 51V NMR
J = 8.0, 1.4 Hz), 7.46 (d, 1H, J = 6.9 Hz), 7.09 (td, 2H, J = 7.8, (105 MHz, CDCl3) 178 ppm; HRMS (FAB) m/z Calcd for
1.4 Hz), 6.75–6.69 (m, 4H), 6.67 (t, 1H, J = 7.8 Hz), 3.57 (s, 6H), C30H22N3O3V1 (M+), 523.1101; Found, 523.1099.
2.23 (s, 3H); 13C NMR (100 MHz, CDCl3) 164.1, 162.8, 137.5,
5c: yield 71%; 1H NMR (400 MHz, CDCl3) δ 7.77–7.75
136.8, 130.7, 129.6, 126.0, 125.9, 123.4, 120.2, 119.9, 117.1, (m, 3H), 7.62 (dd, 1H, J = 6.0, 1.6 Hz), 7.60 (dd, 1H, J = 6.4,
43.7, 16.1 ppm; 51V NMR (105 MHz, CDCl3) 328 ppm; HRMS 1.2 Hz), 7.52–7.47 (m, 3H), 7.31–7.16 (m, 8H), 6.98 (td, 1H,
(FAB) m/z Calcd for C21H20N3O3V1 (M+), 413.0944; Found, J = 8.0, 1.2 Hz), 6.81 (td, 2H, J = 8.0, 1.2 Hz), 6.73–6.71 (m, 2H);
413.0955.
13C NMR (100 MHz, CDCl3) 164.0, 149.3, 141.1, 138.5, 137.3,
4b: yield 71%; 1H NMR (400 MHz, CDCl3) δ 7.60 (dd, 3H, 133.3, 130.4, 129.6, 129.2, 127.1, 126.0, 125.4, 122.1, 121.4,
J = 8.1, 1.4 Hz), 7.14 (td, 3H, J = 8.1, 1.4 Hz), 6.76 (m, 6H), 3.58 121.2, 120.2, 119.6, 117.2 ppm; 51V NMR (105 MHz, CDCl3)
(s, 6H); 13C NMR (100 MHz, CDCl3) 164.3, 137.3, 129.6, 125.8, 206 ppm; HRMS (FAB) m/z Calcd for C30H21Br1N3O3V1 (M+),
120.3, 117.1, 43.7 ppm; 51V NMR (105 MHz, CDCl3) 335 ppm; 601.0206; Found, 601.0223.
HRMS (FAB) m/z Calcd for C20H18N3O3V1 (M+), 399.0788;
Found, 399.0805.
5d: yield 61%; 1H NMR (400 MHz, CDCl3) δ 7.71 (dd, 4H,
J = 8.7, 0.9 Hz), 7.64 (dd, 2H, J = 8.2, 1.4 Hz), 7.50 (t, 4H,
4c: yield 62%; 1H NMR (400 MHz, CDCl3) δ 7.54 (d, 1H, J = 7.8 Hz), 7.45 (d, 1H, J = 8.4 Hz), 7.39–7.17 (m, 7H), 6.84
J = 7.8 Hz), 7.48 (d, 2H, J = 7.8 Hz), 7.33 (d, 1H, 7.8 Hz), 7.08 (td, 2H, J = 7.8, 1.4 Hz), 6.78–6.71 (m, 3H); 13C NMR (100 MHz,
2
1
(t, 2H, J = 7.6 Hz), 6.75–6.68 (m, 4H), 6.59 (t, 1H, J = 7.8), 3.56 CDCl3) 164.1, 152.7 (d, JF–C = 12.5 Hz), 149.3, 148.9 (d, JF–C
=
(s, 6H); 13C NMR (100 MHz, CDCl3) 164.3, 161.9, 137.5, 137.0, 249.2 Hz), 141.0, 139.4 (d, JF–C = 3.8 Hz), 137.2, 130.3, 129.2,
132.3, 129.2, 125.3, 124.6, 119.9, 119.8, 117.0, 110.6, 43.8 ppm; 127.0, 126.0, 122.1, 121.6 (d, 3JF–C = 2.9 Hz), 119.6, 117.2, 116.6
51V NMR (105 MHz, CDCl3) 382 ppm; HRMS (FAB) m/z Calcd (d, 2JF–C = 18.2 Hz) ppm; 51V NMR (105 MHz, CDCl3) 209 ppm;
3
for C20H17Br1N3O3V1 (M+), 476.9893; Found, 476.9911.
HRMS (FAB) m/z Calcd for C30H21F1N3O3V1 (M+), 541.1007;
4d: yield 53%; 1H NMR (400 MHz, CDCl3) δ 7.55 (d, 2H, Found, 541.1004.
J = 7.8 Hz), 7.35 (d, 1H, J = 8.2 Hz), 7.12 (td, 2H, J = 7.8,
X-ray structure analysis
1.4 Hz), 6.92 (td, 1H, J = 9.0, 1.4 Hz), 6.76–6.71 (m, 4H), 6.64
(td, 1H, J = 8.2, 5.5 Hz); 13C NMR (100 MHz, CDCl3) 164.3, All measurements for 4d-DMH-4d and 5b were made on a
2
1
153.1 (d, JF–C = 13.4 Hz), 149.5 (d, JF–C = 247.2 Hz), 139.1 Rigaku R-AXIS RAPID diffractometer using graphite monochro-
3
(d, JF–C = 3.8 Hz), 136.9, 129.6, 125.8, 121.0, 120.3, 118.8 (d, mated Mo Kα radiation. All measurements for 4b were made
3JF–C = 7.7 Hz), 117.1, 116.0 (d, JF–C = 18.2 Hz), 43.7 ppm; on a Rigaku R-AXIS RAPID diffractometer using filtered Mo Kα
2
51V NMR (105 MHz, CDCl3) 378 ppm; HRMS (FAB) m/z Calcd radiation. The structures of 4b, 4d-DMH-4d and 5b were solved
for C20H17F1N3O3V1 (M+), 417.0694; Found, 417.0700.
by direct methods and expanded using Fourier techniques. All
calculations were performed using the Crystal Structure crystal-
lographic software package except for the refinement, which
Synthesis of vanadium(V) diphenylhydrazido complexes 5a–d
A mixture of the corresponding oxidovanadium(V) complex 3 was performed using SHELXL-97. The non-hydrogen atoms
(0.10 mmol), N,N-diphenylhydrazine (33 μL, 0.20 mmol) and a were refined anisotropically. The H atoms were placed in ideal-
small amount of MS4A (4 Å molecular sieves) was stirred in ized positions and allowed to ride with the C atoms to which
dichloromethane (10 mL) under an atmosphere of nitrogen in each was bonded. Crystallographic details are given in Table 1.
a drybox at room temperature for 2 h. The resulting solution Crystallographic data (excluding structure factors) for the
was filtered off, and the filtrate was evaporated under reduced structures reported in this paper have been deposited with the
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Cambridge Crystallographic Data Centre as supplementary
publication no. CCDC-925607 for 4b, CCDC-925608 for
4d-DMH-4d and CCDC-925609 for 5b.
bromoperoxidase, in Vanadium: Biochemical and Molecular
Biological Approaches, ed. H. Michibata, Springer-Verlag,
Berlin, 2012, pp. 127–142.
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Acknowledgements
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This work was supported partly by a Grant-in-Aid for Scientific
Research ACT-C from JST, Japan. We thank Dr Hideki Sugi-
moto and Prof. Shinobu Itoh for the single-crystal X-ray struc-
ture determination, and Dr Masato Ohashi and Prof. Sensuke
Ogoshi for its discussion. Thanks are due to the Analytical
Center, Graduate School of Engineering, Osaka University.
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11830 | Dalton Trans., 2013, 42, 11824–11830
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