Pyrazole metal complex for absorbing carbon dioxide, method for preparing pyrazole metal complex, and method for absorption of carbon dioxide

A method for absorbing carbon dioxide, comprising:

• step (i):
• providing a pyrazole metal complex of formula (I)
• wherein R1 is selected from the group consisting of hydrogen, methyl group, and benzyl group;
• each of R2 and R3 is independently hydrogen;
• and
• M1n+ is selected from the group consisting of Na+, K+, and [K-18-crown-6 ether]+;
• and
• step (ii):
• reacting the pyrazole metal complex with carbon dioxide for absorbing carbon dioxide, wherein a product obtained by reacting the pyrazole metal complex and carbon dioxide is a pyrazole amide formate of formula (II):
• and
• step (iii):
• providing a double nitroso iron complex of formula (III) for reacting with the pyrazole amide formate of formula (II) to obtain a metal complex having structure of formula (IV):
• wherein M is Na+ or K+.