Inorganic Chemistry
Article
dissociative path can involve solvent stabilization: e.g., of the
dissociated metal species as noted by Wilker and Lippard.
Both associative and dissociative mechanisms have been
assigned as operative in a variety of reactivity studies with
metal−thiolates.
In the interest of providing a comprehensive examination of
electrophilic alkylation for complexes of the type M-ER, herein
NMR (C
6
D
6
, 400 MHz): δ 68.8 (4-Pz, s, 3H), 22.3 (m-Ph, SePh, s,
21
2
H), 9.6 (o-Ph, m, 6H), 7.8 (m-Ph, m, 6H), 7.1 (p-Ph, m, 3H), 4.9 (5-
Me, s, 9H), −8.5 (B-H, br, 1H), −23.0 (o-Ph, SePh, s, 2H), −29.8 (p-
−
1
Ph, SePh, s, 2H). FTIR (KBr pellet, ν, cm ): 2545 (B−H). Anal.
Calcd for C H N BNiSe: C, 61.93, H, 4.76, N, 12.04. Found: C,
3
6
33
6
6
1.90, H, 4.68, N, 12.08. μ = 2.80(4) μB.
eff
Ph,Me
Synthesis of [Tp
]Ni(SeC H -4-Cl). To a solution of
6 4
Ph,Me
[Tp
]NiI (370 mg, 0.55 mmol) in toluene (20 mL) was added
are presented the synthesis, characterization, and reactivity of a
a slurry of NaSeC H -4-Cl (181 mg, 0.85 mmol) in toluene (5 mL).
6
4
Ph,Me
series of arylchalcogenolate nickel complexes, [Tp
]Ni-
The solution turned from dark red-brown to dark violet. The reaction
mixture was stirred overnight, followed by removal of the solvent
under vacuum. The product was recrystallized by vapor diffusion of
pentane into a concentrated toluene solution: 273 mg, 67% crystalline
Ph,Me
(
[
EAr). The Tp
Tp
ligand was found to support the series of
]Ni(EAr) complexes, including those for E = O, Se,
Ph,Me
Te and Ar = C H , as well as the arylselenolate series
6
5
−1
−1
Ph,Me
yield. UV−vis (THF): λ , nm (ε, M c m ) 570 (3188), 910
1
max
[Tp
]Ni(SeC H -4-X) (X = H, Cl, Me, OMe) designed to
6 4
(579). H NMR (C D , 400 MHz): δ 69.8 (4-Pz, s, 3H), 22.3 (m-Ph,
6 6
uncover the impact of the electronic effects of the aryl
selenolates on alkylation reactions. The development of the
complete arylchalcogenolate series has presented an oppor-
tunity to explore the reactivity of these complexes. In an effort
to elucidate the nature of the electrophilic alkylation
mechanism for nickel(II) arylchalcogenolates, a combination
of experimental methods and complementary density func-
tional theory (DFT) results is presented.
SePh, s, 2H), 9.2 (o-Ph, m, 6H), 7.8 (m-Ph, m, 6H), 7.0 (p-Ph, m,
3
2
H), 5.2 (5-Me, s, 9H), −8.5 (B-H, br, 1H), −22.2 (o-Ph, SePh, s,
−1
H). FTIR (KBr pellet, ν, cm ): 2537 (B−H). Anal. Calcd for
C H N BNiSeCl: C, 59.02, H, 4.40, N, 11.47. Found: C, 58.75, H,
3
6
32
6
4.19, N, 11.19. μeff = 2.85(6) μ .
B
Ph,Me
Synthesis of [Tp
]Ni(SeC H -4-Me). To a solution of
6 4
Ph,Me
[Tp
]NiI (100 mg, 0.15 mmol) in toluene (20 mL) was added
a slurry of NaSeC H -4-Me (44 mg, 0.23 mmol) in toluene (5 mL).
6
4
The solution turned from dark red-brown to dark blue. The reaction
mixture was stirred overnight, followed by removal of the solvent
under vacuum. The product was recrystallized by vapor diffusion of
pentane into a concentrated toluene solution: 67 mg, 63% crystalline
EXPERIMENTAL SECTION
■
General Considerations. All reactions were performed under an
inert atmosphere of nitrogen either in a Vacuum Atmospheres
glovebox or by using standard Schlenk techniques. All reagents
purchased from commercial sources were used as received. para-
Substituted aromatic diselenide reagents, if not commercially
available, were prepared according to literature methods. Sodium
salts of chalcogenides were prepared through addition of either Na
−1
−1
yield. UV−vis (THF): λmax, nm (ε, M cm ) 585 (5353), 935
1
(915). H NMR (C D , 400 MHz): δ 68.3 (4-Pz, s, 3H), 39.5 (pMe-
6 6
Ph, SePh, s, 3H), 22.3 (m-Ph, SePh, s, 2H), 9.6 (o-Ph, m, 6H), 7.8
(m-Ph, m, 6H), 7.1 (p-Ph, m, 3H), 4.8 (5-Me, s, 9H), −8.4 (B-H, br,
25
−1
1H), −23.7 (o-Ph, SePh, s, 2H). FTIR (KBr pellet, ν, cm ): 2534
(B−H). Anal. Calcd for C37
H N BNiSe: C, 62.40, H, 4.95, N, 11.80.
35 6
26
metal or NaBH to a solution of the corresponding dichalcogenide.
Found: C, 62.19, H, 5.09, N, 11.69. μeff = 2.85(4) μ .
B
4
1
Ph,Me
H NMR spectra were recorded on a Bruker AVIII 400 MHz NMR
spectrometer, and chemical shifts (δ) were referenced to the residual
protons in the deuterated solvents. Electronic absorption spectra were
recorded on a Varian Cary 50 spectrophotometer. Chemical kinetic
reactions monitored through UV−vis were temperature-controlled
using a Unisoku CoolSpek UV Cryostat. Solid-state IR samples were
prepared as KBr pellets, and FT-IR spectra were recorded on a
Nicolet Magna-IR 560 spectrophotometer with a resolution of 4
Synthesis of [Tp
]Ni(SeC
]NiI (100 mg, 0.15 mmol) in toluene (20 mL) was added a
slurry of NaSeC -4-OMe (48 mg, 0.23 mmol) in toluene (5 mL).
6 4
H -4-OMe). To a solution of
Ph,Me
[Tp
H
4
6
The solution turned from dark red-brown to dark blue. The reaction
mixture was stirred overnight, followed by removal of the solvent
under vacuum. The product was recrystallized by vapor diffusion of
pentane into a concentrated toluene solution: 92 mg, 85% crystalline
−1
−1
yield. UV−vis (THF): λmax, nm (ε, M cm ) 600 (4165), 935
−
1
1
cm . The Evans method was used to obtain solution magnetic
(877). H NMR (C D , 400 MHz): δ 68.1 (4-Pz, s, 3H), 21.3 (m-Ph,
6 6
27
moments in toluene-d , at 298 K. High-resolution mass spectra were
SePh, s, 2H), 9.7 (o-Ph, m, 6H), 7.8 (m-Ph, m, 6H), 7.1 (p-Ph, m,
3H), 6.8 (pOMe-Ph, SePh, 3H), 4.7 (5-Me, s, 9H), −8.2 (B-H, br,
8
recorded using a Waters GCT mass spectrometer with a liquid field
desorption ionization (LIFDI) source. Elemental analyses were
−
1
1H), −24.9 (o-Ph, SePh, s, 2H). FTIR (KBr pellet, ν, cm ): 2516
(B−H). Anal. Calcd. for C H N BNiSeO: C, 61.03, H, 4.84, N,
obtained from Robertson Microlit (Ledgewood, NJ).
3
7
35
6
Ph,Me
]Ni(OC H ). To a solution of [TpPh,Me]NiI
Synthesis of [Tp
11.54. Found: C, 61.33, H, 4.76, N, 11.59. μ = 2.78(2) μ .
6
5
eff B
Ph,Me
]Ni(TeC H ). To a solution of [TpPh,Me]NiI
(100 mg, 0.15 mmol) in toluene (15 mL) was added a slurry of
Synthesis of [Tp
6 5
NaOC H (26 mg, 0.22 mmol) in toluene (5 mL). The solution
(140 mg, 0.21 mmol) in toluene (20 mL) was added a solution of
NaTeC H (71 mg, 0.31 mmol) in toluene (5 mL). The solution
6
5
turned from dark red-brown to brown-orange. The reaction mixture
was stirred overnight, followed by removal of the solvent under
vacuum. The product was recrystallized by vapor diffusion of pentane
into a concentrated toluene solution: 64 mg, 67% crystalline yield.
6
5
turned from a dark red-brown to a dark teal. The reaction mixture was
stirred for 2 h, followed by removal of the solvent under vacuum.
Dark green crystals were obtained by diffusion of pentane into an
ethyl ether solution: 83 mg, 53% crystalline yield. UV−vis (THF):
UV−vis (THF): λ , nm (ε, M− cm ) 430 (2608), 500 (sh, 1200),
1
−1
max
1
−1
−1
1
9
05 (273). H NMR (C D , 400 MHz): δ 74.2 (4-Pz, s, 3H), 37.2
λ
, nm (ε, M cm ) 440 (800), 670 (2755). H NMR (C D , 400
6
6
m
a
x
6
6
(
m-Ph, OPh, s, 2H), 16.1 (o-Ph, m, 6H), 8.4 (m-Ph, m, 6H), 7.1 (p-
MHz): δ 66.7 (4-Pz, s, 3H), 19.2 (m-Ph, TePh, s, 2H), 8.2 (o-Ph, m,
6H), 7.6 (m-Ph, m, 6H), 6.9 (p-Ph, m, 3H), 6.5 (5-Me, s, 9H), −5.3
(B-H, br, 1H), −20.2 (o-Ph, TePh, s, 2H), −23.7 (p-Ph, TePh, s, 2H).
Ph, m, 3H), −1.6 (5-Me, s, 9H), −20.5 (B-H, br, 1H), −43.6 (p-Ph,
−
1
OPh, s, 2H), −48.9 (o-Ph, OPh, s, 1H). FTIR (KBr; ν, cm ): 2543
B−H). Combustion analysis was attempted, but adequate results
were not obtained. LIFDI-MS (m/z): calcd for C H N BNiO,
−
1
(
FTIR (KBr, ν/cm ): 2536 (B−H). Anal. Calcd for C H N BNiTe:
36
33
6
3
6
33
6
C, 57.90, H, 4.45, N, 11.25. Found: C, 58.06, H, 4.88, N, 11.61. μ
=
eff
6
34.22; found, 634.22. μ = 3.04(4) μB.
2.73(1) μB.
eff
Ph,Me
]Ni(SeC H ). To a solution of [TpPh,Me]NiI
6 5
Monitoring of the Kinetics of [TpPh,Me]Ni(EAr) Reacting with
Synthesis of [Tp
100 mg, 0.15 mmol) in toluene (15 mL) was added a slurry of
NaSeC H (40 mg, 0.22 mmol) in toluene (5 mL). The solution
(
MeI. All reaction solutions were prepared under a nitrogen
Ph,Me
atmosphere. A 5 mL solution of the appropriate [Tp
]Ni(EAr)
6
5
turned from dark red-brown to deep cobalt blue. The reaction mixture
was stirred overnight, followed by removal of the solvent under
vacuum. The product was recrystallized by vapor diffusion of pentane
into a concentrated toluene solution: 82 mg, 79% crystalline yield.
complex was prepared and placed into a cuvette that was then sealed
with a rubber septum. The reaction kinetics were conducted at 25 °C
under pseudo-first-order conditions. Temperatures were maintained
using a Unisoku CoolSpek UV Cryostat. Neat methyl iodide was
added via a gastight syringe in at least 100-fold excess, ensuring
UV−vis (THF): λmax, nm (ε, M− cm ) 580 (5695), 910 (880). H
1
−1
1
6
328
Inorg. Chem. 2021, 60, 6327−6338