Distortional Effects of Noncovalent Interactions in the Crystal Lattice of a Cp*Ir(III) Acylhydroxamic Acid Complex: A Joint Experimental–Computational Study

[Cp*Ir­(μ-OH)3IrCp*]­OH
reacts with PhCONHOH to
give [Cp*Ir­(η2-ONCOPh)], in which the doubly deprotonated
−NHOH unit binds side-on via N and O, an otherwise unrecorded
binding mode. The X-ray structure shows pyramidalization at Ir together
with secondary bonding between the carbonyl oxygen and Ir (dIr···O = 2.873(8) Å). The
related o-hydroxyphenyl­hydroxamic acid gives
a conventional chelate structure in which both sp3 O atoms
are bound in deprotonated form. In contrast, PhSO2NHOH
reacts with S–N cleavage to give the nitrosyl, [Cp*Ir­(NO)­(SO2Ph)]. A detailed computational analysis identifies noncovalent
interactions in the crystal lattice (crystal-packing effects) as responsible
for the distortion in [Cp*Ir­(η2-ONCOPh)].