Alkyl yttrium complexes of doubly cyclometallated xanthene- and naphthalene-backbone Bis(phosphinimine) ligands

Publication date: Available online 17 October 2019Source: Journal of Organometallic ChemistryAuthor(s): Aathith Vasanthakumar, David J.H. Emslie, James F. BrittenAbstractThe synthesis of a rigid 4,5-bis(triphenylphosphinimino)-2,7-di-tert-butyl-9,9-dimethylxanthene {(Ph3PN)2XT} ligand is outlined, along with a modified synthesis for previously reported 1,8-bis(triphenylphosphinimino)naphthalene {(Ph3PN)2NAP}. Reaction of neutral (Ph3PN)2XT with [Y(CH2SiMe3)3 (THF)2] resulted in double cyclometallation, yielding the base-free monoalkyl complex, [({Ph2(C6H4)PN2XT)Y(CH2SiMe3)] (1). Layering a concentrated THF solution of 1 with hexanes at −28 °C afforded THF-coordinated [({Ph2(C6H4)PN}2XT)Y(CH2SiMe3) (THF)]·2THF (1-THF·2THF), with a distorted pentagonal pyramidal geometry and approximately meridional coordination of the pentadentate {Ph2(C6H4)PN}2XT dianion. Similarly, (Ph3PN)2NAP reacted with [Y(CH2SiMe3)3 (THF)2] to afford a THF-coordinated monoalkyl complex, [{(Ph2(C6H4)PN)2NAP}Y(CH2SiMe3) (THF)] (2-THF). Layering a DME solution of 2-THF with hexanes at −28 °C afforded X-ray quality crystals of [[{(Ph2(C6H4)PN)2NAP}Y(CH2SiMe3) (κ2-DME)]·hexane (2-DME·hexane), with a highly distorted pentagonal pyramidal geometry and a facial coordination mode of the tetradentate {Ph2(C6H4)PN}2NAP dianion.Graphical abstract

Source: Journal of Organometallic Chemistry - October 19, 2019 Category: Chemistry Source Type: research