Terminale und verbrückende Koordination von Indium‐Indium‐Bindungen – bemerkenswerte Polymorphie an der Verbindung In 2 R 2 [(OCC 6 H 5 ) 2 CH] 2 [R = C(SiMe 3 ) 3 ]

Terminal and Bridging Coordination of Indium‐Indium Bonds – Remarkable Polymorphism with the Compound In 2 R 2 [(OCC 6 H 5 ) 2 CH] 2 [R = C(SiMe 3 ) 3 ] Treatment of the dimeric indium(II) subhalide (In 2 R 2 Cl 2 ) 2 ( 1 ) [R = C(SiMe 3 ) 3 ] with four equivalents of lithium dipivaloylmethanide or lithium dibenzoylmethanide afforded by the release of lithium chloride the corresponding diindium diacetylacetonates ( 2 and 3 ). The In‐In single bonds of the products were terminally coordinated by chelating acectylacetonato ligands and the bulky alkyl groups. Three different crystal structures were determined for the dibenzoylmethanide derivative 3 which in the solid state adopted trans and gauche conformations across the In‐In bonds. In contrast to the terminally arranged acetylacetonato ligands of compounds 2 and 3 alkylbenzoato ligands R‐COO − (3,5‐dimethylbenzoate and p ‐ tert ‐butylbenzoate) gave the bridging coordination of the In‐In bonds by two chelating carboxylato groups ( 4 and 5 ). This particular coordination caused a strong shortening of the In‐In bond length in 4 compared to the unsupported bonds in 2 and 3 (264.6 versus 274.7 to 279.3 pm).