Synthesis and Structures of New Borylferrocenes, and Structures of, 2‐Chalcogeno‐bis(aminoboryl)[3]ferrocenophanes and 1,1′‐Tris(di‐methylaminoboryl))][3]ferrocenophane [1, 2]

The reaction of Br 2 BCpFeCp with (Me 3 Si) 2 S affords the hexacyclic tris(ferrocenyl)trithia‐triborine (CpFeCp‐BS) 3 , whereas the tris(ferrocenyl)boroxine is obtained from CpFeCpB(NMe 2 ) 2 and H 2 O via the isolated intermediate [CpFeCpBO) 3 ·HNMe 2 . In this compound there are two ferrocenyl units in trans ‐orientation and a third one is bonded to an O 2 BNHMe 2 unit with formation of a tetracoordinated boron atom (We use the symbol Cp here not only for the C 5 H 5 unit but also for C 5 H 4 or C 5 H 3 units). The structures of several bromo(dialkylamino)borylferrocenes and the 1,1′‐bis[bromo(dialkylamino)boryl]ferrocenes were determined. They show no Fe–B interaction. The Br( R 2 N)B and the ( R 2 N) 2 B groups are increasingly twisted against their Cp planes. In case of 1,1′‐[Br( i Pr 2 N)BCp] 2 Fe the CB(Br)N planes are twisted against the respective Cp planes by 38.7 and 112.5°, which brings the bromine atoms closer to the iron atom. This twisting is enhanced by an increase of the steric demands by the amino groups and is largest for ( i Pr 2 N t BuHNBCp) 2 Fe. The structures of two 1,1′‐chalcogeno‐bis(diorganylaminoboryl)[3]ferrocenophanes X [( R 2 N)BCp] 2 Fe ( X = O. S; R = Me, i Pr) are reported as well as the new 1,1′‐tris(dimethylaminoboryl)[3]ferrocenophane.