Transition-Metal Carbonyl Complexes of 2,5-Diferrocenyl-1-phenyl-1H-phosphole

Dominique Miesel, Alexander Hildebrandt, Marcus Korb, Dieter Schaarschmidt, Heinrich Lang

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Pentacarbonyl(2,5-diferro cenyl-1-phenyl-1Hphosphole)metal complexes 3a-c (3a, M = Cr; 3b, M = Mo; 3c, M = W) have successfully been synthesized by the reaction of 2,5-diferrocenyl-1-phenyl-1H-phosphole (1) with M(CO)(5)(thf) (2a, M = Cr; 2b, M = Mo; 2c, M = W). Further irradiation of 3a-c with 1 equiv of 1 in tetrahydrofuran leads to tetracarbonylbis (2,5 - diferrocenyl-1-phenyl-1H-phosphole)metal complexes 4a-c (4a, M = Cr; 4b, M = Mo; 4c, M = W). In addition, the reaction of 1 with Fe2(C0)9 gave tetracarbonyl(2,5-diferrocenyl-1-phenyl-1H-phosphole)iron (6) and heptacarbonyl [mu- (2,3,4-eta)-1- (2,5- diferro cenyl-1-phenyl-1H-phosphole) diiron (7), respectively. Treatment of 2,5-diferrocenyl- 1-phenyl- 1H-phosphole sulfide ( 8) with Fe-2 (CO)(9) afforded tricarbonyl[(2,3,4,5-eta)-(2,5-diferrocenyl-1-phenyl-1H-phosphole 1-sulfide)]iron (9). Complexes 3b,c, 4c, 7, and 9 have been characterized by single-crystal X-ray diffraction. Molecules 3b,c and 4c exhibit a distorted-octahedral geometry, whereas in 4c the two phosphole units are cis-oriented. Coordination of the dienic system to Fe(C0)3 in 7 and 9, respectively, resulted in a deflection of the phosphorus atom from the C-4 plane. Electrochemical measurements of 3a-c, 4a-c, and 9 demonstrated that the ferrocenyl units can be oxidized separately. The coordination of the dienic system to the Fe(C0)3 building block leads to a decrease of the redox splitting (Delta E degrees' = 190 mV) in comparison to 8 (Delta E degrees' = 240 mV). Mixed-valence [3a-c](+), [4a-c](2+), and [9](+) show IVCT absorptions of weak to moderate strengths. The coordination of the phosphorus atom to M(CO)5 in 3a-c has no significant influence on the metal-metal interaction in the mixed-valent species. However, the coordination of the dienic system in 9 results in a significantly decreased electronic communication of the Pc/Fe termini -via the heterocyclic core.

Original languageEnglish
Pages (from-to)4293-4304
Number of pages12
JournalOrganometallics
Volume34
Issue number17
DOIs
Publication statusPublished - 14 Sep 2015
Externally publishedYes

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