Abstract: Anovel carbon carbon bond free radical initiator diisobutyl 23-dicyano-23-diphenyl succinate(DBCPS) was synthesized and characterized by elemental analysis, IR, FAB MSand ¹H NMRspectroscopy. The crystal structure of the compound DBCPSwas determined by single crystal Xray diffraction techniques. The analytical results show that this crystal belongs to triclinic with space group P₁, and the cell parameters are a=10603(2) nm, b=14702(3) nm, c=07944 nm, α=9340(3)°, β=9912(3)°, γ=10390(3)°, V=11808(4) nm³, Dc=1216 Mg/m³, Z=2, F (000)=452 The molecular structure of DBCPSexhibits as a central symmetry, anti conformation and mesomer and the severe steric hindrance in the molecule also exerts a distinct tension, abnormal bond angle and bond length. Its central C-Cbond length is 01592 nm, there is 0048 nm elongated, and the elongation ratio 311%(the normal bond length is 01544 nm; and its corresponding ethyl derivative is 01585 nm, the elongation ratio is 266%) There are two isomers, both meso and DL, can be found for dimethyl and diethyl derivatives respectively. However, because of the bigger steric hindrance, only one isomer, meso form which has a lower potential energy was obtained for DBCPS. The polymerization of methyl methacrylate(MMA) initiated by DBCPSshowed the number average molecular weight of the polymer(PMMA) increased while both conversion and polymerization time were increased, and the molecular weight distribution decreased with the increasing of reaction time correspondingly. Hence, it is inferred that DBCPScan serves as a thermal iniferter and follows "living" free radical polymerization. The PMMAcapped with the fragments initiated the polymerization of styrene to yield block copolymer PMMAb PSt.

Key words: Carbon carbon bond initiator, Synthesis, Crystal structure, "Living", free radical polymerization