Szesni, Normen and Drexler, Matthias and Maurer, Joerg and Winter, Rainer F. and de Montigny, Frederic and Lapinte, Claude and Steffens, Stefan and Heck, Juergen and Weibert, Bernhard and Fischer, Helmut (2006) Intermetallic communication through carbon wires in heterobinuclear cationic allenylidene complexes of chromium. ORGANOMETALLICS, 25 (24). pp. 5774-5787. ISSN 0276-7333
Full text not available from this repository.Abstract
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.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TRANSITION-METAL-COMPLEXES; HYPER-RAYLEIGH SCATTERING; AZA-COPE REARRANGEMENT; RAY CRYSTAL-STRUCTURE; 3 OXIDATION-STATES; 2 IRON CENTERS; ELECTRON-TRANSFER; SPECTROSCOPIC PROPERTIES; COORDINATED CARBON; MOLECULAR WIRES; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie > Alumni or Retired Professors > Arbeitskreis Prof. Dr. Rainer Winter |
| Depositing User: | Petra Gürster |
| Date Deposited: | 04 Mar 2021 06:49 |
| Last Modified: | 04 Mar 2021 06:49 |
| URI: | https://pred.uni-regensburg.de/id/eprint/33754 |
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