環状オレフィンの開環メタセシス重合に有効な高性能バナジウム錯体触媒の設計·創製

摘要

(Imido)vanadium(V)-alkylidene complexes of type V(NR)(CHSiMe_3)(OR')(PMe_3)_2 [R = Ad, C_6H_5, 2, 6-Me_2C_6H_3, 2, 6C1_2C_6H_3; R' = 2, 6-Me_2C_6H_3, 2, 6-~iPr_2C_6H_3, 2, 6-F_2C_6H_3, C_6F_5, C_6Cl_5, C(CH_3)(CF_3)_2, C(CF_3)_3] exhibited moderate to remarkable catalytic activities for ring-opening metathesis polymerization (ROMP) of norbomene (NBE). In particular, V(N-2,6-Cl_2C_6H_3)(CHSiMe_3)(OC_6X_5)(PMe_3)_2 (X = F, Cl) demonstrated exceptionally high catalytic activities for ROMP of NBE and these complexes polymerize cis-cyclooctene. The catalytic activities increased upon increasing the temperature and the highest activity was observed at 120℃ upon addition of small amount of PMe_3. Cis-specific ROMP of NBE has been attained by V(CHSiMe_3)(N-2, 6-Cl_2C_6H_3)[OC(CF_3)_3](PMe_3)_2, and the activity increased at high temperature with high cis specificity (98%) even at 80℃. This is the rare demonstration of thermally robust, highly cis-specific catalysts, which are apparently different from known molybdenum and ruthenium catalysts.%要旨環状ォレフィンの開環メタセシス重合(Ring-Opening Metathesis Polymerization, ROMP)に高'い触媒活 性を示すィミド配位子およびフエノキシ配位子を有する バナジゥム錯体を設計·創製した．ノルボルネン(NBE) のROMPにおける触媒活性は，配位子上の置換基の影響 を強く受け，V(CHSiMe_3)(N-2,6-Cl_2C_6H_3)(OC_6F_5)(PMe_3)_2が 最も高活性を示した．この錯体ではcis-シクロォクテン (COE)の重合も進行し，高温ほど高活性を示した．さらに V(CHSiMe_3)(N-2,6-Cl_2C_6H_3) [OC(CF_3)_3] (PMe_3)_2によるNBEの ROMPでは，得られるポリマーのォレフィン二重結合がほ とんどcisで，PMe_3の添加により高温で高活性·高選択性 を示した．この種の重合を末端ォレフィン存在下で実施す ると，速やかに連鎖移動反応が進行した．