Method for preparing glutaryl-bridged bis-biogenic guanidine chelate and method for preparing polybutylene succinate

A method for preparing glutaryl-bridged bis-biogenic guanidine chelate (GbG)MX2, the method comprising:

• 1) contacting biogenic guanidine (G) with glutaryl chloride, to yield glutaryl-bridged bis-biogenic guanidine GbG (G-b-G), with a reaction formula as follows:
• wherein, biogenic guanidine (G) is selected from arginine (Arg), guanidine acetic acid (Gaa), creatine (Cra), and creatinine (Cran);
• DMSO is dimethyl sulfoxide;
• operations in 1) comprise:
• adding DMSO to a first reactor, and adding biogenic guanidine (G) and glutaryl chloride to the first reactor, and stirring a first mixture in the first reactor under nitrogen protection;
• recycling DMSO from the first mixture through vacuum distillation and obtaining a resulting first solid;
• transferring the first solid to Buchner funnel, washing the first solid with deionized water and ethanol in sequence, removing the water and ethanol through filtration under reduced pressure, vacuum drying, to yield glutaryl-bridged bis-biogenic guanidine GbG, with a yield of ≥98%;
• 2) mixing the glutaryl-bridged bis-biogenic guanidine GbG as a chelating ligand and a non-toxic metal salt MX2 in an amphiphilic mixed solvent DMSO-H2O for a ligand addition reaction, to yield glutaryl-bridged bis-biogenic guanidine chelate (GbG)MX2, with a reaction formula as follows:
• wherein, M represents Fe2+, Mg2+, or Zn2+;
• and X represents CI−, AcO−(CH3COO−), LaO−(CH3CH(OH)COO−);
• operations in 2) comprise:
• adding the amphiphilic mixed solvent DMSO-H2O to a second reactor, and adding the glutaryl-bridged bis-biogenic guanidine GbG and the non-toxic metal salt MX2 to the second reactor, stirring a second mixture in the second reactor under nitrogen protection;
• recycling the amphiphilic mixed solvent from the second mixture through vacuum distillation and collecting a resulting second solid;
• transferring the second solid in a Buchner funnel, washing the second solid with deionized water and ethanol in turn, decompression draining to remove residual ethanol, vacuum drying, to yield glutaryl-bridged bis-biogenic guanidine chelate (GbG)MX2, with a yield of ≥99%.