An in-depth comparison of the physical and chemical properties of Tetramethylguanidine (TMG) and other common guanidine compounds

Introduction

Guanidine compounds are widely used in organic synthesis, medicinal chemistry, materials science and other fields due to their unique chemical structures and properties. Tetramethylguanidine (TMG), as one of them, has strong alkalinity and good biocompatibility, and has attracted much attention. This article will make an in-depth comparison of the similarities and differences in the physical and chemical properties of TMG and other common guanidine compounds, in order to provide valuable reference for researchers in related fields.

Overview of common guanidine compounds

Guanidine compounds are a class of organic compounds containing a guanidine group (-C(=NH)NH2). Common guanidine compounds include tetramethylguanidine (TMG), 1,1,3,3-tetramethylguanidine (TMBG), 1,1,3,3-tetraethylguanidine (TEBG), 1,1, 3,3-Tetrapropylguanidine (TPBG), etc. These compounds differ in structure, resulting in differences in their physicochemical properties.

Tetramethylguanidine (TMG)

Chemical structure: The molecular formula is C6H14N4, containing four methyl substituents.
Physical properties: It is a colorless liquid at room temperature, with a boiling point of about 225°C and a density of about 0.97 g/cm³. It has good water solubility and organic solvent solubility.
Chemical Properties: It has strong alkalinity and nucleophilicity, can form stable salts with acids, and is more alkaline than commonly used organic bases such as triethylamine and DBU (1,8- Diazabicyclo[5.4.0]undec-7-ene).

1,1,3,3-Tetramethylbiguanide (TMBG)

Chemical structure: The molecular formula is C6H14N4, containing two guanidine groups and four methyl substituents.
Physical properties: It is a white solid at room temperature, with a melting point of about 150-155°C and a density of about 1.18 g/cm³. It is slightly soluble in water and easily soluble in organic solvents.
Chemical properties: It has strong alkalinity and nucleophilicity, can form stable salts with acids, and is more alkaline than TMG.

1,1,3,3-Tetraethylbiguanide (TEBG)

Chemical structure: The molecular formula is C8H18N4, containing two guanidine groups and four ethyl substituents.
Physical properties: It is a colorless liquid at room temperature, with a boiling point of about 240-245°C and a density of about 0.95 g/cm³. It has good water solubility and organic solvent solubility.
Chemical properties: It has strong alkalinity and nucleophilicity, can form stable salts with acids, and is more alkaline than TMG and TMBG.

1,1,3,3-Tripropylbiguanide (TPBG)

Chemical structure: The molecular formula is C10H22N4, containing two guanidine groups and four propyl substituents.
Physical properties: It is a colorless liquid at room temperature, with a boiling point of about 260-265°C and a density of about 0.93 g/cm³. It has good water solubility and organic solvent solubility.
Chemical properties: It has strong alkalinity and nucleophilicity, can form stable salts with acids, and is more alkaline than TMG, TMBG and TEBG.

Comparison of physical and chemical properties

Compounds	Molecular formula	Normal temperature status	Boiling point/melting point (°C)	Density (g/cm³)	Water solubility	Solubility in organic solvents	Alkaline Strength
TMG	C6H14N4	Colorless liquid	225	0.97	Good	Good	Strong
TMBG	C6H14N4	White solid	150-155	1.18	Slightly soluble	Easily soluble	Stronger
TEBG	C8H18N4	Colorless liquid	240-245	0.95	Good	Good	Stronger
TPBG	C10H22N4	Colorless liquid	260-265	0.93	Good	Good	Xeon

Comparison of physical properties

1. Normal temperature state

TMG: It is a colorless liquid at room temperature.
TMBG: It is a white solid at room temperature.
TEBG: It is a colorless liquid at room temperature.
TPBG: It is a colorless liquid at room temperature.

2. Boiling point/melting point

TMG: Boiling point is approximately 225°C.
TMBG: Melting point is approximately 150-155°C.
TEBG: Boiling point is approximately 240-245°C.
TPBG: Boiling point is approximately 260-265°C.

3. Density

TMG: Density is approximately 0.97 g/cm³.
TMBG: Density is approximately 1.18 g/cm³.
TEBG: Density is approximately 0.95 g/cm³.
TPBG: Density is approximately 0.93 g/cm³.

4. Solubility

Water solubility: TMG and TEBG have good water solubility, TMBG is slightly soluble in water, and TPBG has good water solubility.
Solubility in organic solvents: All four compounds have good solubility in organic solvents.

Comparison of chemical properties

1. BaseSexual intensity

TMG: Strongly alkaline and nucleophile.
TMBG: More basic and nucleophile.
TEBG: More basic and nucleophile.
TPBG: Extremely basic and nucleophilic.

2. Reactivity

TMG: Excellent in a variety of organic reactions, such as esterification, cyclization, reduction and oxidation reactions.
TMBG: Shows higher activity in certain reactions, such as Diels-Alder reaction and synthesis of macrocyclic compounds.
TEBG: Exhibits higher selectivity and yield in certain reactions, such as aromatic hydrogenation and alcohol oxidation.
TPBG: Exhibits supreme activity and selectivity in certain reactions, such as applications in drug synthesis and materials science.

Comparison of application fields

1. Organic synthesis

TMG: widely used in esterification reactions, cyclization reactions, reduction reactions and oxidation reactions.
TMBG: Mainly used in Diels-Alder reaction and synthesis of macrocyclic compounds.
TEBG: Used for hydrogenation of aromatic hydrocarbons and oxidation of alcohols.
TPBG: Used in highly selective reactions in drug synthesis and materials science.

2. Medicinal Chemistry

TMG: Used in drug delivery systems such as nanoparticles and liposomes.
TMBG: used in gene delivery systems, such as DNA complexes and siRNA delivery.
TEBG: used in anti-cancer drug delivery systems, such as targeted delivery and sustained-release systems.
TPBG: Used in anti-inflammatory drug delivery systems such as topical and transdermal delivery.

3. Materials Science

TMG: For controlled synthesis and functional modification of polymers.
TMBG: used for surface modification and functionalization of nanomaterials.
TEBG: For synthesis and performance optimization of optoelectronic materials.
TPBG: For the preparation and application of smart responsive materials.

Conclusion

There are significant differences in physical and chemical properties between Tetramethylguanidine (TMG) and other common guanidine compounds. TMG has good water solubility and organic solvent solubility, and is suitable for a variety of organic reactions and drug delivery systems. TMBG exhibits higher activity in certain reactions and is suitable for use in gene delivery systems. TEBG exhibits higher selectivity and yield in the hydrogenation of aromatic hydrocarbons and oxidation of alcohols, making it suitable for anticancer drug delivery systems. TPBG shows supreme activity and selectivity in drug synthesis and materials science, and is suitable for the preparation of anti-inflammatory drug delivery systems and smart response materials.

Through the in-depth comparison in this article, we hope that readers can have a comprehensive and profound understanding of the physical and chemical properties of tetramethylguanidine and other common guanidine compounds, and stimulate more research interests and innovative ideas. Scientific evaluation and rational application are key to ensuring that these compounds reach their maximum potential in various fields. Through comprehensive measures, we can maximize the value of these compounds in scientific research and industrial applications.