Crystal structure of cyclic tris(ferrocene-1,1′-diyl)

Abstract

The molecular structure of the trinuclear title compound, [Fe 3 (C 10 H 8 ) 3 ] {systematic name: tris [-( 5 : 5 )-1,1 0 -bicyclopentadienyl]triiron(II)}, consists of three ferrocene subunits (each with an eclipsed conformation) that are condensed via C-C bonds of the fulvalene moieties into a cyclic trimer. The angles between the planes of the cyclopentadienyl (Cp) rings within the three fulvalene moieties are 76.1 (3), 80.9 (3) and 81.7 (3) . In the crystal, C-HÁ Á Á interactions between neighbouring molecules lead to the cohesion of the structure.Keywords: crystal structure; ferrocene; eclipsed conformation; C-HÁ Á Á interactions.CCDC reference: 1016442 Related literatureThe title compound was obtained as a side product during the synthesis of (ferrocene-1,1 0 -diyl)bis(H-phosphinic acids) (Shekurov et al., 2014). In the molecular structure of the related binuclear ferrocene derivative bis(fulvalene)diiron (Churchill & Wormald, 1969), the Cp rings of the fulvalene moieties are coplanar.

Oligomeric ferrocene rings

“…1a), prepared from pure 1,1′-dibromoferrocene or 1,1′-diiodoferrocene (fc 1 I 2 , fc = ferrocene-1,1′-diyl) 31,32 . The only other reported cyclo(1,1′-oligoferrocene) is cyclo(1,1′-terferrocene) (cyclo [3]), recently observed as a side product during the synthesis of (ferrocene-1,1′-diyl)bis(Hphosphinic acids) 33,34 . To the best of our knowledge, the only other isolated cyclic ferrocene oligomers are isomeric cyclo(1,2-terferrocene)s 23,35 and cyclo(1,1′,2,2′-terferrocene) 36 .…”

Development and Characterisation of Highly Conjugated Functionalised Ferrocenylene Macrocycles

“…For example, previous works have studied the synthesis of molecules which contain direct C−C connections between ferrocene units in the synthesis and isolation of a limited number of biferrocenylene, triferrocenylene and higher‐order macrocycles, albeit in low‐yields [73,74,77–82] . Other groups have utilised longer carbon‐based chains to form connections between ferrocene units.…”

“…However, a number of groups have previously reported the successful isolation of ferrocene-containing macrocycles which could be considered as highly conjugated. [73][74][75][76][77][78][79][80][81][82][83][84][85][86][87] For example, previous works have studied the synthesis of molecules which contain direct CÀ C connections between ferrocene units in the synthesis and isolation of a limited number of biferrocenylene, triferrocenylene and higher-order macrocycles, albeit in low-yields. [73,74,[77][78][79][80][81][82] Other groups have utilised longer carbon-based chains to form connections between ferrocene units.…”

“…Unfortunately, relatively few studies have reported the synthesis of highly conjugated ferrocenylene macrocycles, due to complexities associated with the synthesis of these systems, such as rotation around the ferrocene unit, and the need for cross‐coupling methodologies, which often lead to competitive side‐reactions. However, a number of groups have previously reported the successful isolation of ferrocene‐containing macrocycles which could be considered as highly conjugated [73–87] …”

“…[73][74][75][76][77][78][79][80][81][82][83][84][85][86][87] For example, previous works have studied the synthesis of molecules which contain direct CÀ C connections between ferrocene units in the synthesis and isolation of a limited number of biferrocenylene, triferrocenylene and higher-order macrocycles, albeit in low-yields. [73,74,[77][78][79][80][81][82] Other groups have utilised longer carbon-based chains to form connections between ferrocene units. For instance, a number of ferrocenylene macrocycles have been constructed which contain alkyne, diyne and oligoethylene connections between ferrocene (or biferrocene) motifs.…”