Inorganic Chemistry
Article
2H, J = 8.92, 2.28), 6.76 (d, 2H, J = 8.76), 1.36 (s, 18H). 13C NMR
(600 MHz, DMSO-d6): δ 171.05, 151.33, 139.97, 137.82, 131.55,
120.35, 113.29, 34.17, 31.42. FT-IR (ATR): 921 cm−1 (OUO,
ν3). λmax−1: 648 nm (12 634 M−1 cm−1). HRMS (ESI+) m/z [M + 1]
calcd 1241.4879, found 1241.4877.
groups was required to prepare the H and naphthyl derivatives (UO2-
2c and UO2-2f).
Synthesis of UO2-2a. Acenaphthenequinone (0.091g, 0.50 mmol)
was added to a 100 mL round-bottom flask charged with a stir bar and
heated to 68 °C in methanol (40 mL) with stirring until completely
dissolved. 2-Amino-4-methoxyphenol (0.139 g, 1.0 mmol) and
UO2(OAc)2·2H2O (0.212 g, 0.5 mmol) were added as solids, and
the flask was rinsed with an additional 5 mL of methanol. The
solution turned black within 10 min and was heated and stirred for 24
h, producing a black precipitate. After the solution was cooled to
room temperature, a small quantity of fine, black powder was
collected by filtration and rinsed with copious amounts of methanol.
Attempts to isolate additional product by concentrating the filtrate
and storing it in the freezer were unsuccessful. Yield: 0.064 g, 18.5%.
1H NMR: δ 8.81 (d, 2H, J = 7.28), 8.32 (d, 2H, J = 8.28), 7.93 (t, 2H,
J = 7.85), 7.59 (d, 2H, J = 2.59), 7.17 (dd, 2H, J = 8.98, 2.75), 6.83
(d, 2H, J = 9.80), 3.82 (s, 6H). FT-IR (ATR): 909 cm−1 (OUO,
ν3). λmax−1: 753 nm (5398 M−1 cm−1). Anal. calcd for
C78H54N6O18U3·H2O: C, 44.71; H, 2.69; N, 4.01. Found: C, 44.71;
H, 2.84; N, 4.09.
Synthesis of UO2-1c. A methanolic solution of gbha (0.057 g, 0.23
mmol) was heated to 65 °C in a 100 mL round-bottom flask and
stirred until dissolved. UO2(OAc)2·2H2O (0.100 g, 0.23 mmol) was
dissolved in a minimum amount of hot methanol and added to the
solution. The resulting dark blue solution was stirred at reflux
temperature for 3 h, yielding a dark precipitate. The solution was
cooled to room temperature, and a dark green solid was collected by
filtration. Yield: 0.068 g, 58.2%. Single crystals suitable for X-ray
diffraction were grown by vapor diffusion in a CH2Cl2 solution inside
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a vial of methanol. H NMR (400 MHz, DMSO-d6): δ 9.41 (s, 2H),
7.93 (d, 2H, J = 9.60), 7.46 (t, 2H, J = 4.46), 6.81 (m, 4H). 13C NMR
(600 MHz, DMSO-d6): δ 173.44, 152.76, 139.17, 134.43, 121.53,
118.00, 117.75. FT-IR (ATR): 913, 904 cm−1 (OUO, ν3).
λmax−1: 660 nm (6500 M−1 cm−1). HRMS (ESI+) m/z [M + 1] calcd
509.1227, found 509.1226.
Synthesis of UO2-1d. A methanolic solution (40 mL) of Me-gbha
(0.187 g, 0.7 mmol) was heated to 65°C in a 250 mL round-bottom
flask and stirred until dissolved. UO2(OAc)2·2H2O (0.297 g, 0.7
mmol) was dissolved in a minimum amount of hot methanol and
added to the solution, which turned dark blue. The reaction mixture
was stirred at reflux temperature for 2 h, producing a dark precipitate,
which then was cooled to room temperature. A dark green solid was
Synthesis of UO2-2c. The synthesis of o-trimethylsilyl-2-amino-
phenol was adapted from a published procedure.40 In a 50 mL round-
bottom flask, o-aminophenol (0.437 g, 4.0 mmol) was stirred at room
temperature in dichloromethane (5 mL). Chlorotrimethylsilane (0.51
mL, 4.0 mmol) and triethylamine (0.56 mL, 4.0 mmol) were added;
the mixture was stirred for 18 h, and the solvent was removed using a
rotary evaporator. The product was extracted into pentane and filtered
over a short pad of Celite to remove the triethylamine salt and then
dried to an orange oil which crystallized below room temperature.
Yield: 0.583 g, 80.5%. 1H NMR (400 MHz, CDCl3): δ 6.83−6.74 (m,
3H), 6.65 (td, 1H, J = 7.56, 1.60), 0.32 (s, 9H). 13C NMR (400 MHz,
CDCl3): 142.92, 138.35, 122.13, 118.69, 118.57, 115.81, 0.60.
Acenaphthenequinone (0.091 g, 0.5 mmol) was added to a 250 mL
round-bottom flask charged with a stir bar and heated to 78 °C in
ethanol (30 mL) with stirring until completely dissolved. O-
Trimethylsilyl-2-aminophenol (0.181 g, 1.0 mmol) and UO2(OAc)2·
2H2O (0.212 g, 0.5 mmol) were added, and the flask was rinsed with
an additional 5 mL of ethanol. The reaction mixture turned golden-
brown and was heated and stirred for 18 h, during which time it
turned black. After the solution was cooled to room temperature, a
fine, black powder was collected by filtration. Yield: 0.211 g, 67.0%.
1H NMR (400 MHz, DMSO-d6): δ 7.52 (d, 2H, J = 7.42), 7.17 (d,
2H, J = 8.20), 6.98 (d, 2H, 7.08), 6.81 (t, 2H, J = 7.84), 6.50 (t, 2H, J
= 8.28), 6.01 (m, 4H). FT-IR (ATR): 907, 902 cm−1 (OUO,
ν3). λmax−1: 753 nm (5398 M−1 cm−1). Anal. calcd for C24H14N2O4U·
Cl: C, 43.16; H, 2.11; N, 4.19. Found: C, 43.10; H, 2.23; N, 4.10.
Synthesis of UO2-2d. Acenaphthenequinone (0.091g, 0.50 mmol)
was added to a 250 mL round-bottom flask charged with a stir bar and
heated to 68 °C in methanol (40 mL) with stirring until completely
dissolved. 2-Amino-5-methylphenol (0.123 g, 1.0 mmol) and
UO2(OAc)2·2H2O (0.212 g, 0.5 mmol) were added as solids, and
the flask was rinsed with an additional 5 mL of methanol. The
solution turned dark immediately and was heated and stirred for 1 h,
producing purple precipitate. After the solution was cooled to room
temperature, the purple-black solid was collected by filtration. Yield:
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collected by filtration. Yield: 0.362 g, 96.0%. H NMR (400 MHz,
DMSO-d6): δ 9.30 (s, 2H), 7.78, d, 2H, J = 8.36), 6.62 (m, 4H), 2.35
(s, 6H). 13C NMR (600 MHz, DMSO-d6): δ 150.78, 144.30, 136.79,
121.00, 118.73, 116.99, 21.65. FT-IR (ATR): 915 cm −1 (OUO,
ν3). λmax−1: 613 nm (13 073 M−1 cm−1). HRMS (ESI+) m/z [M + 1]
calcd 537.1540, found 537.1531.
Synthesis of UO2-1e. A solution of glyoxal (40% w/w aq., 0.06 mL,
0.5 mmol) in methanol (5 mL) was heated to 65 °C with stirring.
UO2(OAc)2·2H2O (0.212 g, 0.5 mmol) was dissolved in a minimum
amount of hot methanol and added to the solution. 2-Amino-5-
fluorophenol (0.127 g, 1.00 mmol) was dissolved in ∼20 mL of hot
methanol and added to the reaction mixture, resulting in a dark purple
solution and formation of a dark precipitate. The solution was heated
and stirred for 5 h and then cooled to room temperature, and the dark
solid was collected by filtration. Yield: 0.164 g, 60.2%. Single crystals
suitable for X-ray diffraction were grown by vapor diffusion from a
THF solution inside a vial of pentane. 1H NMR: δ 8.40 (s, 2H), 7.99
(t, 2H, J = 7,42), 6.67 (m, 2H). 13C NMR (600 MHz, DMSO-d6): δ
174.15 (d), 167.78, 166.12, 152.72, 136.05, 118.77, 106.77, 104.95.
FT-IR (ATR): 919 cm−1 (OUO, ν3). λmax−1: 575 nm (9542 M−1
cm−1). HRMS (ESI+) m/z [M + Na] calcd 1111.1818, found
1111.1838.
Attempted Synthesis of UO2-1f. Several methods of synthesizing
UO2-1f were employed to acquire pure product; however, the poor
solubility of both the ligand (and stability of the cyclic form) and the
complex precludes their separation. Reaction of the ligand with uranyl
acetate in hot methanol either with or without base, in an 80:20
THF:methanol mixture with base, and by templation in methanol
with and without base each yielded a dark brown product which, by
NMR, contains a 50:50 mixture of the metal complex and ligand.
Attempts to separate the ligand from the complex with a variety of
solvent systems (including THF, THF/methanol mixtures, hexanes,
and dichloromethane) were unsuccessful. After these attempts, a
reduction in the ligand peaks was not observed by NMR; hence, the
complex may be unstable in solution. We were able to obtain a single
crystal of the product by crystallization from a benzene/methanol
mixture and pentane to confirm its identity. FT-IR (ATR): 917, 910
(OUO, ν3). λmax−1: ∼640 nm (∼4600−4900 M−1 cm−1). HRMS
(ESI+) m/z [M + 1] calcd 609.1540, found 609.1540
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0.184 g, 55.7%. H NMR (400 MHz, DMSO-d6): δ 8.78 (d, 2H, J =
7.37), 8.32 (d, 2H, J = 8.19), 7.98 (d, 2H, J = 8.68), 7.87 (t, 2H, J =
7.82), 6.70 (m, 4H), 4.11 (4, 2H, J = 5.25, MeOH), 3.17 (d, 6H, J =
5.25, MeOH), 2.39 (s, 6H). 13C NMR (600 MHz, DMSO-d6): δ
171.07, 160.22, 156.51, 143.20, 135.37, 131.34, 131.23, 128.33,
127.17, 123.20, 120.94, 120.60, 117.40, 21.76. FT-IR (ATR): 897
cm−1 (OUO, ν3). λmax−1: 674 nm (6611 M−1 cm−1). Anal. calcd
for C52H36N4O8U2·4(H2O): C, 44.84; H, 3.18; N, 4.02. Found: C,
44.86; H, 3.18; N, 4.00.
Synthesis of UO2-2e. Acenaphthenequinone (0.063 g, 0.35 mmol)
was added to a 100 mL round-bottom flask charged with a stir bar and
heated to 68 °C in methanol (40 mL) with stirring until completely
dissolved. 2-Amino-5-fluorophenol (0.102 g, 0.8 mmol) and
UO2(OAc)2·2H2O (0.170 g, 0.40 mmol) were added as solids, and
the flask was rinsed with an additional 5 mL of ethanol. The reaction
Synthesis of Phen-BIAN Complexes. The complex UO2-2b was
synthesized according to the previously published procedure.22 The
other phen-BIAN complexes were synthesized by templation of the
substituted ligand around uranyl. Protection of the alcohol with TMS
D
Inorg. Chem. XXXX, XXX, XXX−XXX