Preparation and structure of [Cr2IIIF3(TPyA)2](BF4)3 [TPyA = tris(2-pyridylmethyl)amine] possessing terminal and bridging fluorides

Reaction of [CrIII(NCMe)6](BF4)3 with tris(2-pyridylmethyl)amine (TPyA) in MeCN results in a fluoride abstraction from BF4- yielding the formation of the unexpected [Cr2IIIF3(TPyA)2](BF4)3 that has a linear, symmetric F− bridging two CrIII ions with each CrIII ion also having a terminal fluoride. Antiferromagnetic coupling is observed between the two CrIII ions with a J/kB of −19 K (−13 cm−1) (H = −2JSa · Sb), and this is an order of magnitude stronger than expected for two bent fluoride linkages.

Fluoride abstraction from BF4- leads to the formation of [Cr2IIIF3(TPyA)2](BF4)3 that possesses two terminal as well as one bridging fluorides.Figure optionsDownload as PowerPoint slide