Crystal structures of di-μ-bromido-bis{di-bromido-[η-2-(di-methyl-amino)-inden-yl]zirconium(IV)} and di-bromido-bis-[η-2-(di-methyl-amino)-inden-yl]zirconium(IV).

In the title compounds, [ZrBr(CHN)], (I) and [ZrBr(CHN)], (II), the positions of the η-binding 2-di-methyl-amino-indenyl units are fixed by intra-molecular C-H⋯Br inter-actions involving aromatic or di-methyl-amino H atoms. The binuclear mol-ecule of (I) is located on a general position, while the mononuclear mol-ecule of (II) is situated on a twofold rotation axis. Both Zr atoms in (I) are ligated by one cyclo-penta-dienyl (CP) ring and four Br ligands (two bridging, two terminal), while in (II) the Zr atom is ligated by two CP rings and two terminal Br ligands. The crystal structures of both (I) and (II) comprise of strands of π-π- and N-π-bonded mol-ecules, which in turn are linked by C-H⋯Br inter-actions.