Supporting Information
Table of Contents
1.
General
2.
Preparation of Compound 1
3.
Preparation of Compound 2-4
4.
Preparation of Compound 5-6
5.
Preparation of Compound 7
6.
Preparation of Compound 8
7.
Preparation of Compound 9
8.
Preparation of Compound 10
9.
Preparation of Compound 11
10. Preparation of Compound 12
11. Stability of W3O2 Clusters
General
The chemicals used for the synthetic work were of reagent grade quality and were used as obtained.
NMR spectra were recorded on Bruker Avance 300 or 400 MHz instruments at ambient temperature in D 2O or
CDCl3. The residual solvent protons were used as internal standards. Chemical shifts are reported in parts per
million (ppm), and coupling constants are reported in hertz (Hz). Splitting patterns are reported as singlet (s),
doublet (d), triplet (t) and broad triplet (bt). Splitting patterns that could not be interpreted or easily visualized are
designated as multiplet (m).
Compound 1-12 were analyzed and characterized by the following HPLC based analytical methods to determine
characteristic retention time and mass spectrum:
Method 1: UPLC (ACN-HCOOH):
Instrument: Waters Acquity UPLC-MS SQD 3001; column: Acquity UPLC BEH C18 1.7 50x2.1mm; eluent A:
water + 0.1% formic acid, eluent B: acetonitril; gradient: 0-1.6 minutes 1-99% B, 1.6-2.0 minutes 99% B; flow 0.8
mL/minute; temperature: 60 °C; injection: 2 µL; DAD scan: 210-400 nm; ELSD
Method 2: UPLC (ACN-HCOOH polar):
Instrument: Waters Acquity UPLC-MS SQD 3001; column: Acquity UPLC BEH C18 1.7 50x2.1mm; eluent A:
water + 0.1% formic acid, eluent B: acetonitril; gradient: 0-1.7 minutes 1-45% B, 1.7-2.0 minutes 45-99% B; flow
0.8 mL/minute; temperature: 60 °C; injection: 2 µL; DAD scan: 210-400 nm; ELSD
The animals were kept under standard laboratory conditions at a temperature of 22°C and a dark/light rhythm of 12
hours. Standard food (ssniff R/M-H from Sniff, Germany) and water were provided ad libitum. The animals were
handled and treated according to the German animal welfare regulations.
2. Preparation of Compound 1
Monoaqua-κO-hexakis(µ-acetato-κ2O)-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–
W)(IV)
H
H
O
O
O
H3C
W
O
O
O
H3C
O
O
W
OH
CH3
4+
2-
O
O
2-
4+
W
CH3
4+
O
OH
O
O
O
O
CH3
CH3
Sodium hexakis(µ-acetato-κ2O)-tris(acetato-κO)-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV)
H3C
O
O
H3C
O
O
W
O
H3C
O
O
O
W
H3C
O
O
O
CH3
4+
2-
O
O
2-
4+
O
W
O
O
4+
CH3
O
O
O
+
Na
CH3
CH3
O
CH3
A suspension of sodium tungstate (26.4 g, 89.8 mmol) and tungsten hexacarbonyl (Aldrich, 97% purity, 130.4 g,
359.4 mmol) in acetic anhydride (2173 mL, 23.0 mol) was heated to 80°C. Air (approx. 5 L per minute) was
bubbled through the mixture for 15 minutes, then the air stream was stopped and the bath temperature was raised to
145°C. After 18 hours, the mixture was cooled to rt. The yellow-brownish precipitate was filtered, washed with
acetic anhydride (100 mL), THF (200 mL) and tert-butylmethyl ether (200 mL) and dried (50°C, 50 mbar) to give
sodium hexakis(µ-acetato-κ2O)-tris(acetato-κO)-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV) (127.8g,
112.3 mmol, 93,7% based on tungsten hexacarbonyl).
1
H-NMR (300 MHz, deuterium oxide) δ = 2.08 (s, 9 H), 2.28 (s, 18 H) ppm.
LC/MS ES- m/z 1115.03 (M-23).
Sodium hexakis(µ-acetato-κ2O)-tris(acetato-κO)-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV) (20 g,
17.6 mmol) was refluxed in water (500mL) for 15 hours. The mixture was concentrated under vacuum and
lyophilized to yield 18.3 g of raw monoaqua-κO-hexakis(µ-acetato-κ2O)-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6Otriangulo-tritungsten(3 W–W)(IV) together with sodium acetate and acetic acid.
1
H-NMR (300 MHz, deuterium oxide) δ = 2.25 (s, 18 H) ppm.
LC/MS ES- m/z = 989.3 (M-1).
3. Preparation of Compound 2 - 4
3,3'-[Ethane-1,2-diylbis(oxy)]dipropanoic acid
O
HO
O
OH
O
O
3,3'-[Ethane-1,2-diylbis(oxy)]dipropanoic acid was synthesized analogous to Ashikaga et al. Bull.Chem.Soc.Jpn
1988, 61, 2443-2449 via bis nitrile.
1
H-NMR (300 MHz, D2O) δ = 2.62 (t, 4H), 3.63 (s, 4H), 3.75 (t, 4H) ppm.
A suspension of 3,3'-[ethane-1,2-diylbis(oxy)]dipropanoic acid (750 mg, 3.64 mmol) and hexakis(µ-acetato-κ2O)monoaqua-κO-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV) (1.8 g, 1.82 mmol) in acetic acid
(0.63 mL, 10.9 mmol) and water (36 mL) was irradiated in a micowave reactor for one at 120°C. The reaction
mixtures were filtrated and the fitrate was concentrated in vacuum. Separation on a preparative HPLC (YMC RP C18 AQ 10μm, acetonitrile water + acetic acid) yielded 44 mg of compound 2, 66 mg of compound 3 and 71 mg of
compound 4.
Compound 2 (cis)
Tetra-µ-acetato-1κ2O1,O2:2κ3O1’,O3,O4:3κ3 O2’,O3’,O4’-)- monoaqua-κO-{µ3-3,3’-[ethanediylbis(oxy)] dipropanoato}1κO1:2κ2O1’,O2:3κO2’-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV)(3 W–W) compound 2(cis)
O H
H
W
O
4+
O
O
O
O
O
O
O
2-
O
2-
4+
W
O OH
O
O
1
O
W
O
O
4+
OH
O
H-NMR (300 MHz, D2O) δ = 2.19 (s 3H), 2.26 (s, 6H), 2.27 (s, 3H), 2.64 - 2.77 (m, 2H), 2.78 - 2.92 (m, 2H), 3.42
- 3.52 (m, 2H), 3.53 - 3.63 (m, 4H), 3.90 (td, 2H) ppm.
LC/MS ES- m/z = 1074.94 (M-1).
Compound 3 (trans)
Tetra-µ-acetato-1κ2O1,O2:2κ4O3,O4:3κ4 O1’,O2’,O3’,O4’-monoaqua-κO-{µ-3,3’-[ethanediylbis(oxy)] dipropanoato}1κ2O:2κ2O’-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV)(3 W–W) compound 3 (trans)
O H
H
W
O
O
4+
O
O
O
O
O
O
O
2-
O
O
2-
O
4+
W
O
OH
1
W
O
4+
OH
O
O
H-NMR (300 MHz, D2O) δ = 2.27 (s, 12H), 2.74 (t, 4H), 3.59 (s, 4H), 3.82 (t, 4H) ppm.
LC/MS ES- m/z = 1074.29 (M-1).
Compound 4 (cis, trans)
Monoaqua-κO-di-µ-acetato-1κO:2κO’:2κO:3κO’-{µ3-3,3’-[ethanediylbis(oxy)]dipropanoato}-1κO1:2κ2O1’,O2:3κO2’{µ-3,3’-[ethanediylbis(oxy)]dipropanoato}-1κ2O:3κ2O’-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulotritungsten(IV)(3 W–W)
O H
H 4+
W
O
O
O
O
O
O
O
O
O
2-
O
2-
O
O
4+
W
O OH
O
O
1
W
O
O
4+
OH
O
H NMR (300 MHz, D2O) δ = 2.27 (s, 6H), 2.63 - 2.79 (m, 6H), 2.80 - 2.93 (m, 2H), 3.41 - 3.52 (m, 2H), 3.53 - 3.64
(m, 4H), 3.59 (s, 4H), 3.82 (t, 4H), 3.92 (td, 2H) ppm.
LC/MS ES- m/z = 1158.60 (M-1).
4. Preparation of Compound 5 - 6
A suspension of 3,3'-[ethane-1,2-diylbis(oxy)]dipropanoic acid (250 mg, 3.64 mmol) and hexakis(µ-acetato-κ2O)monoaqua-κO-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV) (400 mg, 0.404 mmol) in water (36
mL) was irradiated in a micowave reactor for 15 minutes at 140°C. The reaction mixture was filtrated and the fitrate
was concentrated in vacuum. Separation on a preparative HPLC (YMC RP C-18 AQ 10μm, acetonitrile, water +
acetic acid) yielded 76 mg of compound 5 and 67 mg of compound 6.
Compound 5 (cis, cis, trans)
Monoaqua-κO-bis{µ3-3,3’-[ethanediylbis(oxy)]dipropanoato-1κO1:2κ2O1’,O2:3κO2’}{µ-3,3’[ethanediylbis(oxy)]dipropanoato}1κ2O1,O2:3κ2O1’,O2’-{µ-3,3’-[ethanediylbis (oxy)]dipropanoato}-1κ2O:2κ2O’dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV)(3 W–W)
O H
H 4+
W
O
O
O
O
O
O
O
O
O
2-
O
2-
4+
W
O OH
O
O
O
O
O
W
O
O
4+
OH
O
O
1
H-NMR (300 MHz, D2O) δ = 2.65 - 2.80 (m, 8 H), 2.81 - 2.94 (m, 4 H), 3.42 - 3.54 (m, 4 H), 3.55 - 3.68 (m, 12
H), 3.84 (t, 4 H), 3.94 (td, 4 H) ppm.
LC/MS ES- m/z = 1247.12 (M-1).
Compound 6 (trans trans trans)
Monoaqua-κO-tris{µ-3,3’-[ethanediylbis(oxy)]dipropanoato}1κ4O1,O2,O3,O4: 2κ4O1’,O2’,O5,O6:3κ4O3’,O4’,
O5’,O6’-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV)(3 W–W)
O H
H 4+
W
O
O
O
O
O
O
O
O
O
O
O
2-
O
O
2-
O
4+
W
OH
O
W
O
OH
O
O
O
1
4+
O
H NMR (300 MHz, D2O) δ = 2.79 (t, 12 H), 3.61 (s, 12 H), 3.85 (t, 12 H) ppm.
LC/MS ES- m/z = 1246.86 (M-1).
5. Preparation of Compound 7
Monoaqua-κO-bis{µ3-3,3’-[propane-1,3-diylbis(oxy)]dipropanoato-1κO1:2κ2O1’,O2: 3κO2’}{µ-3,3’-[propane1,3-diylbis(oxy)]dipropanoato}1κ2O1,O2:3κ2O1’,O2’-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulotritungsten(IV)(3 W–W)
O
O H
H W 4+
O
O
O
O
O
O
O
2-
O
2-
O
O
3,3'-[Propane-1,2-diylbis(oxy)]dipropanoic acid
O
W
O
O
O
O
4+
W
O OH
O
O
4+
OH
O
O
O
HO
O
O
OH
3,3'-[Propane-1,2-diylbis(oxy)]dipropanoic acid was synthesized analogous to Senkyr et al. Analytical Chemistry
1979, 51, 786 via bis nitrile.
1
H-NMR (400 MHz, D2O) δ = 1.78 (quin, 2H), 2.60 (t, 4H), 3.54 (t, 4H), 3.71 (t, 4H) ppm.
A suspension of 3,3'-[propane-1,2-diylbis(oxy)]dipropanoic acid (267 mg, 1.21 mmol) and hexakis(µ-acetato-κ2O)monoaqua-κO-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV) (400 mg, 0.40 mmol) in acetic acid
(93 µL, 1.62 mmol) and water (30 mL) was irradiated in a micowave reactor for 15 minutes at 140°C. The reaction
mixtures were filtrated and the fitrates was concentrated in vacuum. Separation on a preparative HPLC (YMC RP C18 AQ 10μm, acetonitrile, water + acetic acid) yielded 30.6 mg monoaqua-κO-bis{µ3-3,3’[propanediylbis(oxy)]dipropanoato-1κO1:2κ2O1’,O2:3κO2’}{µ-3,3’-[propane diylbis(oxy)]dipropanoato}1κ2O1,O2:2κ2O1’,O2’-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV)(3 W–W)
1
H-NMR (300 MHz, D2O) δ = 1.58 - 1.68 (m, 4 H), 1.75 - 1.86 (m, 2 H), 2.63 - 2.86 (m, 12 H), 3.31 (t, 8 H), 3.54
(t, 4 H), 3.73 - 3.96 (m, 12 H) ppm.
LC/MS ES- m/z = 1289.21 (M-1).
6. Preparation of Compound 8
Monoaqua-κO-bis(µ3-3,3’-{oxybis[2,1-ethanediylbis(oxy)]}dipropanoato-1κO1: 2κ2O1’,O2:3κO2’)(µ-3,3’{oxybis[2,1-ethanediylbis(oxy)]}dipropanoato)1κ2O1,O2: 3κ2O1’,O2’-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6Otriangulo-tritungsten(IV)(3 W–W)
O H
O
H
W
O
O
4+
O
O
O
O
O
O
O
O
2-
O
2-
O
O
O W
OH
O
4+
W
O
O
O
O
4+
OH
O
O
O
3,3'-[Oxybis(ethane-2,1-diyloxy)]dipropanoic acid
O
HO
O
O
O
O
OH
3,3'-[Oxybis(ethane-2,1-diyloxy)]dipropanoic acid was synthesized analogous to Ashikaga et al. Bull.Chem.Soc.Jpn
1988, 61, 2443-2449 via bis nitrile.
1
H-NMR (300 MHz, D2O) δ = 2.64 (t, 4H), 3.64 (s, 8H), 3.76 (t, 4H) ppm.
A suspension of 3,3'-[oxybis(ethane-2,1-diyloxy)]dipropanoic acid (303 mg, 1.21 mmol) and hexakis(µ-acetatoκ2O)-monoaqua-κO-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV) (400 mg, 0.40 mmol) in water
(30 mL) was irradiated in a micowave reactor for 15 minutes at 140°C. The reaction mixtures were filtrated and the
fitrate was concentrated in vacuum. Separation on a preparative HPLC (YMC RP C-18 AQ 10μm, acetonitrile,
water + acetic acid) yielded 37 mg of monoaqua- O-bis(µ3-3,3’-{oxybis[2,1-ethanediylbis(oxy)]}dipropanoato1κO1:2κ2O1’,O2:3κO2’)(µ-3,3’-{oxybis[2,1-ethanediylbis (oxy)]}dipropanoato)1κ2O1,O2:3κ2O1’,O2’-dihydroxidoκ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(IV)(3 W–W).
1
H NMR (400 MHz, D2O) δ = 2.80 - 2.89 (m, 8 H), 2,91 - 2.96 (m, 4H), 3.49 - 3.56 (m, 8 H), 3.57 - 3.61 (m, 8 H),
3.66 - 3.70 (m, 4 H), 3.72 - 3.75 (m, 4 H), 3.83 - 3.92 (m, 12 H) ppm.
LC/MS ES- m/z = 1379.09 (M-1).
7. Preparation of Compound 9
Monoaqua-κO-bis{µ3-3,3’,3’’-[methylidynetris(methyleneoxy)]tripropanoato1κ2O1,O2:2κ2O1’,O3:3κ2O2’,O3’}dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV)
O
O
O
H
O
H
O
H O
O
4+
W
O
O
O
O
O
O
O
W
O
2-
H
O
O
O
2-
O
O
4+
W
OH
4+
OH
O
3-{3-(3-Tert-butoxy-3-oxopropoxy)-2-[(3-tert-butoxy-3-oxopropoxy)methyl]propoxy}propanoate
O
CH3
O
O
CH3
CH3
O
O
H
O
O
O
O
CH3
CH3
CH3
CH3
CH3
CH3
2-(Hydroxymethyl)propane-1,3-diol (2.0 g, 18.8 mmol) and tert-butyl prop-2-enoate are stirred in DMSO (3.3 mL)
and 5 M aqueous sodium hydroxide solution (0.37 mL) at 20°C for 48 hours. The mixture was concentrated and the
residue was purified by chromatography on silica gel (ethyl acetate in hexane, 20 to 100%) to yield 0.29 g of tertbutyl 3-{3-(3-tert-butoxy-3-oxopropoxy)-2-[(3-tert-butoxy-3-oxopropoxy)methyl]propoxy}propanoate and 2.7 g of
the di- or mono ether which were reacted under the same conditions to yield additional 4.0 g of the desired triether
compound.
1
H-NMR (400 MHz, CDCl3): δ = 1.47 (s, 27 H), 2.08 - 2.21 (m, 1 H), 2.46 (t, 6 H), 3.44 (d, 6 H), 3.63 (t, 6 H) ppm.
3-{3-(2-Carboxyethoxy)-2-[(2-carboxyethoxy)methyl]propoxy}propanoic acid
O
O
OH
O
H
O
OH
OH O
O
To a solution of tert-butyl 3-{3-(3-tert-butoxy-3-oxopropoxy)-2-[(3-tert-butoxy-3-oxopropoxy)methyl]propoxy}propanoate (4.0 g, mmol) in dioxane (20 mL) was added 6 M aqueous hydrochloric acid (6.5 mL,
39 mmol) and a 4 M solution of hydrochloric acid in dioxane (16.3 mL, 65.2 mmol). After stirring for 120 hours the
solvent was removed under vacuum to yield 2.66 g 3-{3-(2-carboxyethoxy)-2-[(2-carboxyethoxy)methyl]propoxy}propanoic acid as a yellow oil.
1
H-NMR (400 MHz, D2O) δ = 2.11 (m, 1 H), 2.58 (t, 6 H), 3.46 (d, 6 H), 3.69 (t, 6 H) ppm.
LC/MS ES+ m/z 323.44 (M+1).
A suspension of 3-{3-(2-carboxyethoxy)-2-[(2-carboxyethoxy)methyl]propoxy}propanoic acid (2.6 g, 8.06 mmol)
and monoaqua-κO-hexakis(µ-acetato-κ2O)- dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–
W)(IV) (4.0 g, 4.03 mmol) in acetic acid (462 µL, 8.06 mmol) and water (300 mL) was separated into 10 pressure
vessels which were irradiated in a microwave reactor for 15 minutes at 140°C. The reaction mixtures were filtrated
and the combined filtrates were concentrated in vacuum. Separation on a preparative HPLC (YMC RP C-18 AQ
10μm, acetonitrile water + acetic acid) yielded 0.56g of monoaqua-κO-bis{µ3-3,3’,3’’-[methylidynetris(methyleneoxy)]tripropanoato-1κ2O1,O2:2κ2O1’,O3:3κ2O2’,O3’}dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulotritungsten(3 W–W)(IV) after lyophilization.
1
H-NMR (400 MHz, D2O) δ = 1.71 - 1.82 (m, 2 H), 2.77 (br. t, 12 H), 3.43 (d, 12 H), 3.86 (br. t, 12 H) ppm.
LC/MS ES- m/z 1273.06 (M-1).
8. Preparation of Compound 10
Monoaqua-κO-bis{µ3-3,3’,3’’-[aminomethylidynetris(methyleneoxy)]tripropanoato1κ2O1,O2:2κ2O1’,O3:3κ2O2’,O3’}dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV)
O
O
O
H2 N
O
H
O
H O
O
4+
W
O
O
O
O
O
O
O
O
W
2-
NH2
O
O
O
2-
O
O
4+
W
4+
OH
OH
O
Tert-butyl 3-{2-amino-3-(3-tert-butoxy-3-oxopropoxy)-2-[(3-tert-butoxy-3-oxopropoxy)methyl]propoxy}propanoate
O
O
CH3
CH3
CH3
CH3
O
CH3
CH3
O
O
H2 N
O
O
O
CH3
CH3
CH3
O
Tert-butyl 3-{2-amino-3-(3-tert-butoxy-3-oxopropoxy)-2-[(3-tert-butoxy-3-oxopropoxy)methyl]propoxy}propanoate was synthesized following the procedure of Cardona, C.M.; Gawley, R.E. J. Org. Chem. 2002,
67, 1411 – 1413 yielding 16.2 g product starting from 15.7 g tris(hydroxymethyl)amino methane after
chromatography on silica gel.
1
H-NMR (400 MHz, CDCl3) δ = 1.46 (s, 27 H), 2.46 (t, 6 H), 3.32 (s, 6 H), 3.65 (t, 6 H) ppm.
3-{2-Amino-3-(2-carboxyethoxy)-2-[(2-carboxyethoxy)methyl]propoxy}propanoic acid
O
O
OH
O
H2 N
O
OH
OH O
O
To a solution of tert-butyl 3-{2-amino-3-(3-tert-butoxy-3-oxopropoxy)-2-[(3-tert-butoxy-3oxopropoxy)methyl]propoxy}propanoate (9.3 g, 18.9 mmol) in dioxane (16.4mL) was added 6 molar aqueous
hydrochloric acid (2.6 mL, 15.5 mmol) and a 4 molar solution of hydrochloric acid in dioxane (6.5 mL, 25.9 mmol).
After stirring for 96 hours the solvent was removed under vacuum to yield the hydro chloride salt, which was treated
with ion exchange resin IRA 67 for three days. The ion exchange resin was washed with water followed by 20%
aqueous acetic acid. The washing solutions were fractionated and fractions where no chloride was detected were
concentrated under vacuum to yield 1.0 g 3-{2-amino-3-(2-carboxyethoxy)-2-[(2carboxyethoxy)methyl]propoxy}propanoic acid as free base.
1
H-NMR (300 MHz, D2O) δ = 2.55 (t, 6 H), 3.59 (s, 6 H), 3.66 - 3.81 (m, 6 H) ppm.
A suspension of 3-{2-amino-3-(2-carboxyethoxy)-2-[(2-carboxyethoxy)methyl]propoxy}propanoic acid (2.94 g,
8.73 mmol) and monoaqua-κO-hexakis(µ-acetato-κ2O)- dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulotritungsten(3 W–W)(IV) (4.32 g, 4.36 mmol) in acetic acid (500 µL, 8.73 mmol) and water (136 mL) was separated
into 10 pressure vessels which were irradiated in a microwave reactor for 15 minutes at 140°C. The reaction
mixtures were filtrated and the combined filtrates were concentrated in vacuum. Separation on a preparative HPLC
(acetonitrile / water + acetic acid) yielded monoaqua-κO-bis{µ3-3,3’,3’’-[aminomethylidynetris(methyleneoxy)]tripropanoato-1κ2O1,O2:2κ2O1’,O3:3κ2O2’,O3’}dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten (3 W–
W)(IV).
1
H-NMR (300 MHz, D2O) δ = 2.83 (t, 12 H), 3.55 (s, 12 H), 3.93 (t, 12 H) ppm.
LC/MS ESI- m/z 1303 (M-1).
For the generation of crystalline triaqua-κ3O-bis{µ3-3,3’,3’’-[aminomethylidynetris(methyleneoxy)]tripropanoato1κ2O1,O2:2κ2O1’,O3:3κ2O2’,O3’}di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV) dichloride the W3O2
complex was prepared from 3-{2-amino-3-(2-carboxyethoxy)-2-[(2-carboxyethoxy)methyl]propoxy}propanoic acid
in form of its hydrochloride. Final crystallization was done from a water acetonitrile mixture.
9. Preparation of Compound 11
Monoaqua-κO- bis{µ3-3,3’,3’’-[propane-1,2,3-triyltris(oxy)]tripropanoato-1κ2O1,O2:2κ2O1’,O3:3κ2O2’,O3’}
dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten (3 W–W)(IV)
O
O
O
O
H
H
O
O
O
O
O
O
O
W
OH
4+
H
O
O
4+
W
2-
O
O
O
2-
O
O
O
O
W
H
4+
OH
O
Tert-butyl 3-[2,3-bis(3-tert-butoxy-3-oxopropoxy)propoxy]propanoate
CH3
O
O
CH3
O
CH3
CH3
O
O
H
CH3
CH3
O
O
O
CH3
O
CH3
CH3
To propan-1,2,3-triol (105 g, 1.14 mol) and tert-butyl prop-2-enoate (835 mL, 5.7 mol) in DMSO (248 mL) was
added a 5 molar aqueous sodium hydroxide solution (22.8 mL, 114 mmol) at 5°C. The mixture is quenched with
aqueous NH4Cl solution and extracted with ethyl acetate. The mixture was concentrated and the residue was purified
by chromatography on silica gel (ethyl acetate in hexane, 20 to 100%) to yield 12.3 g of tert-butyl 3-[2,3-bis(3-tertbutoxy-3-oxopropoxy)propoxy]propanoate.
1
H-NMR (400 MHz, CDCl3): δ = 1.45 (s, 27 H), 2.48 (t, 6 H), 3.43 - 3.54 (m, 4 H), 3.58 (m, 1 H), 3.68 (t, 4 H), 3.81
(t, 2 H) ppm.
3,3',3''-[Propane-1,2,3-triyltris(oxy)]tripropanoic acid
O
O
OH
OH
O
H
O
O
OH
O
To a solution of tert-butyl 3-[2,3-bis(3-tert-butoxy-3-oxopropoxy)propoxy]propanoate (12.3 g, 23.2 mmol) in
dioxane (99 mL) was added 6 molar aqueous hydrochloric acid (18.6 mL, 111 mmol) and a 4 molar solution of
hydrochloric acid in dioxane (46.5mL, 186mmol). After stirring for 24 hours additional 6 molar aqueous
hydrochloric acid (1.86 mL, 11.1 mmol) and a 4 molar solution of hydrochloric acid in dioxane (4.65mL,
18.6mmol) was added and the solution was stirred for 2 hours at 40°C. The organic solvent was removed under
vacuum, water was added to the residue and a final lyophilization yielded 8.0 g of 3,3',3''-[propane-1,2,3-triyltris(oxy)]tripropanoic acid.
1
H-NMR (400 MHz, deuterium oxide) δ = 2.59 (t, 2 H), 2.60 (t, 4 H), 3.50 (dd, 2 H), 3.58 (dd, 2 H), 3.67 - 3.70 (m,
1 H), 3.69 - 3.77 (m, 4 H), 3.81 (t, 2 H) ppm.
A suspension of 3,3',3''-[propane-1,2,3-triyltris(oxy)]tripropanoic acid (187 mg, 0.61 mmol) and monoaqua-κOhexakis(µ-acetato-κ2O)- dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV) (400 g, 0.404
mmol) in acetic acid (90 µL, 0.81 mmol) and water (30 mL) was separated into 5 pressure vessels which were
irradiated in a microwave reactor for 15 minutes at 120°C. The reaction mixtures were filtrated and the filtrate was
concentrated in vacuum. Separation on a preparative HPLC (YMC RP C-18 AQ 10μm, acetonitrile, water + acetic
acid) yielded 8.4 mg of monoaqua-κO-bis{µ3-3,3’,3’’-[propane-1,2,3-triyltris(oxy)]tripropanoato-1κ2O1,O2:
2κ2O1’,O3:3κ2O2’,O3’}dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O- triangulo-tritungsten (3 W–W)(IV).
1
H-NMR (300 MHz, deuterium oxide) δ = 2.70 (br. t, 4H), 2.77 (br. t, 8H), 3.21 - 3.32 (m, 2H), 3.37 (d, 8H), 3.69 -
3.86 (m, 8H), 3.87 - 4.02 (m, 8H) ppm.
LC/MS ES- m/z = 1244.75 (M-1).
10. Preparation of Compound 12
Monoaqua-κO-bis(µ3-3,3’,3’’-{[(2,3-dihydroxypropyl)amino]methylidynetris(methyleneoxy)}tripropanoato1κ2O1,O2:2κ2O1’,O3:3κ2O2’,O3’)-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV)
O
O
OH
HO
H
N
O
O
H
O
H O
O
O
O
W
OH
4+
2-
O
OH
O
O
O
H
N
O
O
O
OH
O
4+
W
O
2-
O
O
W
4+
OH
O
3-{3-(2-carboxyethoxy)-2-[(2-carboxyethoxy)methyl]-2-[(2,3-dihydroxypropyl)amino]propoxy}propanoic acid
O
CH3
O
O
OH
O
H
N
HO
CH3
CH3
O
O
O
CH3
CH3
CH3
O
CH3
O
CH3
CH3
Tert-butyl 3-{2-amino-3-(3-tert-butoxy-3-oxopropoxy)-2-[(3-tert-butoxy-3-oxopropoxy)methyl]propoxy}propanoate (25 g, 49.4 mmol) and rac-2,3-dihydroxypropanal were shaken under an hydrogen atmosphere
in methanol in presence of 10% palladium on charcoal (263 mg) for 18 hours at room temperature. The mixture was
filtered through cellites and concentrated in vacuum. The residue was purified by chromatography on silica gel
(ethyl acetate in hexane, 20 to 100%) to yield 12.47 g of tert-butyl 3-{3-(3-tert-butoxy-3-oxopropoxy)-2-[(3-tertbutoxy-3-oxopropoxy)methyl]-2-[(2,3-dihydroxypropyl)amino]propoxy}propanoate as light yellow oil.
1
H-NMR (400 MHz, CDCl3): δ = 1.46 (s, 27 H), 2.47 (t, 6 H), 2.76 (dd, 1 H), 2.87 (dd, 1 H), 3.37 (s, 6 H), 3.54 -
3.79 (m, 3 H), 3.64 (t, 6H) ppm.
3-{3-(2-Carboxyethoxy)-2-[(2-carboxyethoxy)methyl]-2-[(2,3-dihydroxypropyl)amino]propoxy}propanoic
acid
O
O
OH
HO
OH
O
H
N
O
OH
OH O
O
To a solution of tert-butyl 3-{3-(3-tert-butoxy-3-oxopropoxy)-2-[(3-tert-butoxy-3-oxopropoxy)methyl]-2-[(2,3dihydroxypropyl)amino]propoxy}propanoate (4.8 g, 8.3 mmol) in dioxane (48 mL) was added 6 molar aqueous
hydrochloric acid (6.6 mL, 39.6 mmol) and a 4 molar solution of hydrochloric acid in dioxane (16.6 mL, 66 mmol).
After stirring for 40 hours the solvent was removed under vacuum to yield the hydro chloride salt, which was treated
with ion exchange resin IR 67 (200mL) in water for two hours. The ion exchange resin was washed with water
followed by 15 % aqueous acetic acid. The washing solutions were fractionated and fractions with a negative
chloride detection were combined and concentrated under vacuum to yield 3.18 g 3-{3-(2-carboxyethoxy)-2-[(2carboxyethoxy)methyl]-2-[(2,3-dihydroxypropyl)amino]propoxy}propanoic acid as free base.
1
H-NMR (300 MHz, deuterium oxide) δ = 2.54 (t, 6 H), 3.05 (dd, 1 H), 3.23 (dd, 1 H), 3.54-3.58 (m, 2 H), 3.65 (s,
6H), 3.71 (t, 6 H), 3.83 - 3.95 (m, 1 H) ppm.
A suspension of 3-{3-(2-carboxyethoxy)-2-[(2-carboxyethoxy)methyl]-2-[(2,3-dihydroxypropyl)amino]propoxy}propanoic acid (1.58 g, 3.84 mmol) and monoaqua-κO-hexakis(µ-acetato-κ2O)-dihydroxido-κ2O-diµ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV) (1.9 g, 1.92 mmol) in acetic acid (220 µL, 3.84 mmol) and
water (136 mL) was separated into 5 pressure vessels which were irradiated in a microwave reactor for 15 minutes at
140°C. The reaction mixtures were filtrated and the combined filtrates were concentrated in vacuum. Separation on
a preparative HPLC (YMC RP C-18 AQ 10μm, acetonitrile water + acetic acid) yielded 0.24 g of monoaqua-κObis(µ3-3,3’,3’’-{[(2,3-dihydroxypropyl)amino]methylidynetris(methyleneoxy)}tripropanoato1κ2O1,O2:2κ2O1’,O3:3κ2O2’,O3’)-dihydroxido-κ2O-di-µ3-oxido-1:2:3κ6O-triangulo-tritungsten(3 W–W)(IV).
1
H-NMR (300 MHz, deuterium oxide) δ = 2.80 (t, 12 H), 2.99 - 3.10 (m, 2 H), 3.14 - 3.25 (m, 2 H), 3.48 - 3.66 (m,
16 H), 3.89 (t, 14 H) ppm.
LC/MS ES- m/z = 1451.1 (M-1).
11. Stability of W3O2 Clusters
The stability of W3O2 clusters was determined in aqueous, buffered solution at pH 7.4. The solution containing 5
mmol/L of the compound in a tightly sealed vessel in which the air had been replaced by an argon atmosphere was
heated to 121 °C for 45 min in a steam autoclave. In case of the formation of insoluble material, the precipitated
material was removed by centrifugation. The tungsten concentration of the solution was determined by ICP-OES
before and after heat treatment. The integrity of the compound was determined by HPLC analysis before and after
heat treatment. Absolute stability was calculated as the ratio of the peak area of the compound after and before the
heat treatment multiplied with the ratio of the tungsten concentration of the solution after and before heat treatment.
HPLC system:
Column: Symmetry C18, 4.6 x 75 mm (Waters).
Solvent A1: 0.1 mM Na-citrate, pH 6-7
Solvent A2: 5 mM tetrabutylammonium phosphate pH 6
Solvent A3: 100 mM NH4-acetate pH 6-7
For selection of solvents A1 to A3 see the table below.
Solvent B: methanol, HPLC grade
Gradient: a linear gradient starting from 100 % A and 0% B and ending at 5% A and 95% B after 10 min was used.
Flow: 1 mL/min
Two Detector were used in a serial connection: UV-vis, 200-600 nm, at 254 nm and specific absorption of W 3O2clusters at 460 nm. The UV-detector was connected to an ICP-MS running at m/z 184 for 184W, the most abundant
isotope of tungsten.
Chromatographic
conditions
Compound
Stability
Solvent A
1
55 %
A2
2
45 %
A2
3
54 %
A2
4
80 %
A2
5
100 %
A1
6
100 %
A1
9
100 %
A3
10
100 %
A3
11
100 %
A3
12
100 %
A3
No