Abstract: To provide a method for producing a compound that enhances dispersibility of a pigment of respective colors in a water-insoluble solvent, as well as a pigment dispersant, and a pigment composition, a pigment dispersion and a toner having a good tinting power. A method for producing a compound, including the following: (i): subjecting a polymerizable monomer forming a monomer unit represented by formula (1) to radical polymerization in the presence of a radical polymerization initiator and an iodine molecule to provide a polymer; and (ii): binding a colorant to a terminal of a main chain of the polymer: wherein R1 represents a hydrogen atom and an alkyl group, and R2 represents a phenyl group, a carboxyl group, an alkoxycarbonyl group or a carboxamide group.

Abstract: Provided are a method of producing a compound having a colorant structure suitable for a pigment dispersant, and a pigment dispersant, a pigment composition, a pigment dispersion, and a toner each containing the compound. The production method is a method of producing a compound in which a polymer portion and a colorant portion are bonded to each other through a linking group, the method including the steps of: (a) polymerizing a vinyl-based polymerizable monomer represented by the formula (A) with a radical initiator having a protective group by living radical polymerization to provide a polymer having the protective group at a terminal thereof; (b) hydrolyzing the protective group of the polymer having the protective group at a terminal thereof obtained by the step (a) to deprotect the polymer; and (c) bonding the deprotected polymer obtained by the step (b) and a colorant to each other through a covalent bond.

Abstract: A ligand molecule-immobilized polymer has a structure represented by the following general formula (1). In the general formula (1), R1 represents a ligand molecule-containing group, R2 represents a hydrophobic group, R3 represents a spacer site, R4 represents a hydrophilic group, R5 represents a group having charge, a to d specify a composition ratio and each represent an integer of 1 or more, and n and m specify chain lengths and represent integers satisfying the relationships of 1?n(a+b+c+d)?10,000 and 1?m?350.

Abstract: A ligand molecule-immobilized polymer has a structure represented by the following general formula (1). In the general formula (1), R1 represents a ligand molecule-containing group, R2 represents a hydrophobic group, R3 represents a spacer site, R4 represents a hydrophilic group, R5 represents a group having charge, a to d specify a composition ratio and each represent an integer of 1 or more, and n and m specify chain lengths and represent integers satisfying the relationships of 1?n(a+b+c+d)?10,000 and 1?m?350.