Synthesis of (η6-arene)tricarbonylmetal and (σ-nitrogen)pentacarbonylmetal complexes of 1,2,3,4-tetrahydroquinoline and 1,2,3,4-tetrahydroisoquinoline with chromium, molybdenum and tungsten

Thermal reactions of [M(CO)6] with 1,2,3,4-tetrahydroquinoline (1) afford the corresponding (η6-arene)tricarbonylmetal complex (M=Cr, 3; M=Mo, 4; and M=W, 5). In contrast, thermolysis of the same hexacarbonyl complexes with 1,2,3,4-tetrahydroisoquinoline (2) affords the (σ-nitrogen)pentacarbonylmetal derivatives (M=Cr, 7; M=Mo, 8; and M=W, 9). For chromium the (η6-arene)tricarbonylmetal complex (6) was also isolated. X-ray crystal structures are reported for 3, 4, 7 and 9.