Crystal structure of chlorido-bis-[(1,2,5,6-η)-cyclo-octa-1,5-diene]iridium(I).

A K Fazlur Rahman,William D Jones,William W Brennessel,Miles Wilklow-Marnell

doi:10.1107/s2056989017000809

A K Fazlur Rahman, William D Jones + Show 2 more

Open Access

https://doi.org/10.1107/s2056989017000809

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Abstract

The title complex, [IrCl(C8H12)2], was synthesized directly from the reaction of IrCl3·3H2O with a large excess of cod (cod = cyclo-octa-1,5-diene) in alcoholic solvent. Large yellow needles were obtained by the slow cooling of a hot solution. Based on the positions of the chloride ligand and the mid-points of the four C=C bonds, the mol-ecule adopts a five-coordinate geometry that is midway between square pyramidal and trigonal bipyramidal. The material crystallizes in the ortho-rhom-bic space group Pbca with one mol-ecule per asymmetric unit in a general position and shows no significant inter-molecular inter-actions. Individual mol-ecules are aligned along [010], and these rows form a pseudo-hexa-gonal packing arrangement.

Highlights

A few years later it was reported that a cyclooctene-ligated dimer [Ir(C8H14)2(-Cl)]2
We have found that if Herde’s preparation using IrCl33H2O is carried out with a large excess of cod (10 ), the product isolated after removal of the alcoholic solvent is IrCl(cod)2 (Fig. 1)
This was apparent as the red–orange reaction mixture, which contained a mixture of red [Ir(cod)(-Cl)]2 and yellow

Summary

Chemical context

Analogous to thermally unstable IrCl(C2H4), which releases ethylene to form the (slightly) more stable dimer [Ir(C2H4)2(-Cl)]2 (Onderdelinden & van der Ent, 1972), IrCl(cod) readily generates stable [Ir(cod)(-Cl)]2 with the loss of one equivalent of cod per iridium. We have found that if Herde’s preparation using IrCl33H2O is carried out with a large excess of cod (10 ), the product isolated after removal of the alcoholic solvent is IrCl(cod) (Fig. 1). This was apparent as the red–orange reaction mixture, which contained a mixture of red [Ir(cod)(-Cl)]2 and yellow. Mid-point(C C) distances as they would involve the same metal and ligand orbitals, while ideal TBP geometry ( 5 = 1).

Structural commentary

Database survey

Synthesis and crystallization

Refinement