The novel flexible polymers with even alkyl chains P-1

P-2 and P-3 are prepared from the monomers S-M-1

S-M-2 and S-M-3 with (R

R)-1

2-aminocyclohexane via a nucleophilic addition-elimination reaction

respectively.The Eu(Ⅲ)-grafting chiral polymers P-4

P-5 and P-6 prepared from the corresponding non-conjugated chiral polymers P-1

P-2 and P-3 by direct coordination reaction of Eu(TTA)32H2O displayed high quantum yield and tunable circularly polarized luminescence (CPL).The CD profile and glum value of dissymmetry of CPL for Eu(Ⅲ) varied with alkyl length of P-1

P-2

and P-3 with high luminescent efficiency observed for P-4

P-5 and P-6.The P-4

P-5 and P-5 all exhibit exclusively red color emission from Eu(Ⅲ) (5D07F2) transition due to almost complete excitation energy transfer from the macromolecular chain to the Eu(TTA)3 moiety.The fluorescent efficiency of P-4

P-5 and P-6 could be tuned by choicing the alkyl chain and further corroborated by emission quantum yields and emission lifetimes.The glum values of the dissymmetry factors of CPL for electronic dipole (5D07F2) transition of Eu(Ⅲ) for P-4 and P-5 are as large as +0.0873 and +0.0115

respectively

whereas P-6 exhibits the largest glum value of about +0.0539 at magnetic dipole (5D07F1) transition.Tunable CPL and luminescent efficiency for Eu(Ⅲ) of corresponding Eu(Ⅲ)-grafting polymer reveal the decisive role of alkyl chain in determining asymmetric coordination environment of Eu(Ⅲ).