Zusammenfassung
The reaction of [(CO)(5)M(THF)] (M = Cr, W) with lithiated 2-ethynylquinoline followed by alkylation of the resulting alkynylpentacarbonylmetalate with [R3O]BF4 (R = Me, Et) gives allenylidene complexes in which the terminal carbon atom of the allenylidene chain is part of an N-alkylated quinoline ring. The reaction of [(CO)5M(THF)] (M = Cr, W) with lithiated 2-ethynylpyridine derivatives, Li[C ...
Zusammenfassung
The reaction of [(CO)(5)M(THF)] (M = Cr, W) with lithiated 2-ethynylquinoline followed by alkylation of the resulting alkynylpentacarbonylmetalate with [R3O]BF4 (R = Me, Et) gives allenylidene complexes in which the terminal carbon atom of the allenylidene chain is part of an N-alkylated quinoline ring. The reaction of [(CO)5M(THF)] (M = Cr, W) with lithiated 2-ethynylpyridine derivatives, Li[C equivalent to CC5H4BrN], and [Et3O]BF4 affords allenylidene complexes that contain a terminal six-membered N-heterocycle brominated at the 5- or 6-position. Various alkynyl groups can be introduced into the 5-position of the ring through [PdCl2(PPh3)(2)]-catalyzed coupling of the 5-bromo-substituted allenylidene complexes with the terminal alkynes HC equivalent to CR '(R ' = TMS, Ph, C10H21, 4-C6H4-C equivalent to CPh, 4-C6H4-C equivalent to CH, Fc (Fc = (C5H4)FeCp), 4-C6H4-C equivalent to CFc, 4-C6H4-C equivalent to CC6H4C equivalent to CFc). The analogous replacement reaction of the 6-bromo-substituted chromium complex with HC equivalent to CFc yields the corresponding 6-ferrocenylalkynyl-substituted complex. Desilylation of [(CO)(5)Cr=C=C=C(CH)(2)C(C equivalent to CSiMe3)CHNEt] (6a) gives [(CO)(5)Cr=C=C= C(CH)(2)C(C equivalent to CH)CHNEt] (15a). CuI-catalyzed coupling of 15a with {M}-Br ({M}) Ru(CO)(2)Cp, Fe- CO)(2)Cp*) affords the binuclear complexes [(CO)(5)Cr=C=C=C(CH)(2)C(C equivalent to C-{M})CHNEt]. The symmetrical binuclear complex is formed by oxidative coupling of 15a with [Cu(OAc)(2)]. The attachment of a ferrocenyl group to the chromium center via PPh2 to give cis-[(CO)(4)(Ph(2)PFc)Cr=C=C=C(CH)(4)NEt] is achieved via displacement of a cis-CO ligand in [(CO)(5)Cr=C=C=C(CH)(4)NEt] by PPh(2)Fc. On addition of Co-2(CO)(8) to [(CO)(5)Cr=C=C=C(CH)(2)C(C equivalent to CPh)CHNEt] a Co-2(CO)(6) unit adds to the C equivalent to C bond to form a trinuclear complex. The ferrocenyl unit in [(CO)(5)Cr=C=C=C(CH)(2)C(C equivalent to CR)CHNEt] (R = Fc, C6H4C equivalent to CFc, C6H4C equivalent to CC6H4C equivalent to CFc) is readily oxidized. Spectroelectrochemical studies (IR, UV/vis) confirm that in the oxidized form there is strong electronic communication of the ferrocenyl group with the (CO)(5)Cr unit.