5,6-BENZO-4,7,13,16,21,24-HEXAOXA-1,10-DIAZABICYCLO[8.8.8]HEXACOS-5-ENE Property

Boiling point:

557.6±50.0 °C(Predicted)

Density 

0.995 g/mL at 25 °C

refractive index 

n20/D 1.516

Flash point:

40 °F

pka

7.11±0.20(Predicted)

BRN 

586455

Safety

Hazard Codes 

F,Xn,Xi

Risk Statements 

11-20-36/37/38-67-65-48/20-38-63

Safety Statements 

16-25-26-29-36/37/39-62-36/37

RIDADR 

UN 1993 3/PG 2

WGK Germany 

3

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

H336May cause drowsiness or dizziness

H373May cause damage to organs through prolonged or repeated exposure

H412Harmful to aquatic life with long lasting effects

Precautionary statements

P201Obtain special instructions before use.

P202Do not handle until all safety precautions have been read and understood.

P273Avoid release to the environment.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P308+P313IF exposed or concerned: Get medical advice/attention.

5,6-BENZO-4,7,13,16,21,24-HEXAOXA-1,10-DIAZABICYCLO[8.8.8]HEXACOS-5-ENE Chemical Properties,Usage,Production

Uses

5,6-Benzo-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacos-5-ene can be used as a model ligand:
In the metal-ligand complex formation studies to predict ligand coordination with metal ions (Eu & Gd) using magnetic resonance imaging (MRI) technique.
In the study of coordination environment as well as redox and electronic properties of its Yb^II complexes.

Reactions

[Eu(2.2.2B)Cl][BPh4]·2CH3OH. (2.2.2B = C22H36N2O6): In an argon atmosphere glovebox, 14.0 mg of EuCl2 was dissolved in 1.5 mL of distilled methanol in a 20 mL scintillation vial. Separately, 50.0 mg of [NBu4][BPh4] was dissolved in THF dropwise in a 6 mL scintillation vial. The [NBu4][BPh4] was carefully pipetted into the methanolic solution containing EuCl2 with stirring. 222 μL of a 0.1 M solution of 2.2.2B cryptand in THF was added to the reaction mixture which was briefly stirred before being allowed to sit overnight undisturbed. Colorless block crystals of [Eu(2.2.2B)Cl][BPh4]·2CH3OH formed overnight (Yield: 67.7%). Crystals were isolated via pipet and stored under immersion oil until single-crystal X-ray diffraction analysis could be performed. 1H NMR (CD3CN-d3): 7.30 (s, CH, 2H), 7.02 (s, CH, 2H), 6.87 (s, CH, 1H), 6.32 (s, broad), 3.67 (m, CH2O), 3.30 (s, CH3), 2.18 (s, OH, 1H), 1.83 (s, CH2) (Figure S3). PXRD analysis appears in the Supporting Information (SI) (Figure S5).
[Eu(2.2.2B)(CH3OH)][BPh4]2·CH3OH. Synthesis of [Eu(2.2.2B)(CH3OH)][BPh4]2·CH3OH was achieved as described for [Eu(2.2.2B)Cl][BPh4]·2CH3OH with the exception of the dissolution of the [NBu4][BPh4] solid in acetonitrile rather than THF. Combination of the two colorless solutions produced a yellow solution. Addition of 222 μL of 0.1 M 2.2.2B cryptand in THF yielded no distinguishable change, but colorless block crystals of [Eu(2.2.2B)(CH3OH)][BPh4]2·CH3OH formed overnight (Yield: 74.2%). These crystals were isolated and stored in the same fashion as [Eu(2.2.2B)Cl][BPh4]·2CH3OH. 1H NMR (CD3CN-d3): 7.30 (s, CH, 2H), 7.01 (s, CH, 2H), 6.86 (s, CH, 1H), 6.21 (s, broad), 3.66 (s, CH2O), 3.28 (s, CH3), 2.27 (s, OH, broad), 1.82 (s, CH2) (Figure S4). PXRD analysis appears in the SI (Figure S6).
A solution of 5,6-benzo-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacos-5-ene (2.2.2B cryptand, 50% wt in toluene, Sigma-Aldrich) was prepared by first isolating the ligand in vacuo, and a 0.1 M stock solution of 2.2.2B cryptand in THF was prepared.
[1] TODD N. POE. Understanding the Stabilization and Tunability of Divalent Europium 2.2.2B Cryptates[J]. Inorganic Chemistry, 2021, 60 11: 7815-7826. DOI:10.1021/acs.inorgchem.1c00300.

Structure and conformation

Figure S3. 1H NMR spectrum of [Eu(2.2.2B)Cl][BPh4] ? 2CH3OH. Major peaks that did not experience significant broadening are labelled.

Figure S4. 1H NMR spectrum of [Eu(2.2.2B)(CH3OH)][BPh4]2 ? CH3OH. The significant broadening of the methanol signal at 2.27 ppm is attributed to the coordination of methanol to the cryptate complex, unlike in [Eu(2.2.2B)Cl][BPh4] ? 2CH3OH.