4-tert-Butylcalix[4]arene-tetraacetic acid tetraethyl ester
[CAS 97600-39-0]

Identification

• Classification: Chemical reagent >> Organic reagent >> Ester >> Ethyl ester compound
• Name: 4-tert-Butylcalix[4]arene-tetraacetic acid tetraethyl ester
• Molecular Formula: C₆₀H₈₀O₁₂
• Molecular Weight: 993.27
• CAS Registry Number: 97600-39-0
• EC Number: 619-280-6
• SMILES: CCOC(=O)COC1=C2CC3=CC(=CC(=C3OCC(=O)OCC)CC4=C(C(=CC(=C4)C(C)(C)C)CC5=C(C(=CC(=C5)C(C)(C)C)CC1=CC(=C2)C(C)(C)C)OCC(=O)OCC)OCC(=O)OCC)C(C)(C)C

Properties

• Density: 1.1$+/-$0.1 g/cm³ Calc.^*
• Melting point: 153 - 158 $degree$C (Expl.)
• Boiling point: 911.5$+/-$65.0 $degree$C 760 mmHg (Calc.)^*
• Flash point: 339.7$+/-$34.3 $degree$C (Calc.)^*
• Index of refraction: 1.529 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P264-P270-P271-P280-P301+P312+P330-P302+P352-P304+P340+P312-P305+P351+P338-P332+P313-P337+P313-P362-P403+P233-P405-P501

Discovery and Applications

4-tert-Butylcalix[4]arene-tetraacetic acid tetraethyl ester is a functionalized calixarene derivative belonging to the class of macrocyclic phenolic compounds. It is based on calix[4]arene, a cyclic tetramer composed of four phenolic units linked by methylene bridges at the para positions, forming a bowl-shaped macrocyclic structure. In this derivative, each phenolic unit is substituted at the upper rim with a tert-butyl group, and at the lower rim with tetraacetic acid ester functionalities in the form of ethyl esters.

The parent framework, calix[4]arene, is a macrocycle formed by the condensation of p-substituted phenols with formaldehyde under basic conditions. The resulting structure has a rigid yet conformationally flexible cavity that can adopt several conformations, including cone, partial cone, 1,2-alternate, and 1,3-alternate forms. The cone conformation is often stabilized in heavily substituted derivatives such as tert-butylcalix[4]arene due to steric effects.

In this compound, the four phenolic hydroxyl groups at the lower rim of calix[4]arene have been functionalized into acetic acid ester substituents, specifically –CH₂COOEt groups. This transformation introduces four ester-linked side arms, giving the molecule multiple coordination sites and increasing its ability to interact with metal ions or polar guest species. The ester groups also enhance solubility in organic solvents relative to the parent calixarene.

The tert-butyl groups at the upper rim serve both steric and electronic roles. Sterically, they lock the macrocycle into a more defined conformation, often favoring the cone structure. Electronically, they influence the aromatic ring system by donating electron density through inductive effects, which can subtly modify binding and reactivity at the lower rim.

Calixarene derivatives such as this compound are widely studied as host molecules in supramolecular chemistry. Their cup-like cavity allows them to bind guest species through noncovalent interactions such as hydrogen bonding, van der Waals forces, and π–π interactions. The presence of flexible ester arms further extends binding capability by providing additional coordination sites.

The tetraacetic acid ester substituents can participate in coordination chemistry, particularly with metal ions. The carbonyl oxygen atoms in the ester groups can act as electron donors, enabling formation of metal–ligand complexes. This property makes such calixarene derivatives useful in extraction chemistry, molecular recognition, and sensor design.

The synthesis of 4-tert-butylcalix[4]arene derivatives typically begins with tert-butylcalix[4]arene, followed by stepwise functionalization of the phenolic hydroxyl groups. Alkylation with ethyl bromoacetate or related haloacetates under basic conditions introduces the acetic ester substituents. Controlled reaction conditions are required to achieve full tetra-substitution at the lower rim.

From a structural perspective, the calix[4]arene core provides a preorganized cavity, while the flexible ester side arms can adapt to binding events. This combination of rigidity and flexibility is a key feature in host–guest chemistry, allowing selective binding of ions or neutral molecules depending on size and functionality.

In solution, calixarene derivatives may exhibit conformational dynamics, although bulky substituents such as tert-butyl groups tend to restrict inversion and stabilize a dominant conformation. This conformational control is important for reproducible molecular recognition behavior.

These compounds are of interest in areas such as ion sensing, molecular encapsulation, and selective extraction of metal ions or organic molecules. Functionalized calixarenes can be designed to recognize specific guests based on cavity size, charge distribution, and coordination geometry.

Overall, 4-tert-butylcalix[4]arene-tetraacetic acid tetraethyl ester is a heavily functionalized calixarene macrocycle featuring a tert-butyl-substituted aromatic upper rim and tetra-esterified acetic acid groups at the lower rim. Its combination of a rigid macrocyclic cavity and multiple coordinating ester groups makes it a versatile platform in supramolecular chemistry, molecular recognition, and coordination chemistry studies.

References

2026. A modular potentiometric sensor platform with detachable microfluidics for multiplexed analysis of low-volume biofluids. Analytical sciences : the international journal of the Japan Society for Analytical Chemistry.
DOI: 10.1007/s44211-026-00876-3