4,5-BIS(DIPHENYLPHOSPHINO)ACRIDINE - A NEW-TYPE OF TRIDENTATE PHOSPHORUS-NITROGEN-PHOSPHORUS LIGANDS

Reaction of 4,5-difluoroacridine (8) with two equivalents of potassium diphenylphosphide (Ph2PK) yielded the title compound 3. Contrarily, d iphenylphosphine (Ph2PH) reacted with 8 under addition, and 4,5-difluo ro-9-diphenyl-9,10-dihydroacridine (12) was obtained. Compound 8 was p repared from 2-amino-3-fluorobenzoic acid (13) in a four step synthesi s. As it is shown by the preparation of the metal complexes 4,5-bis(di phenylphosphino)acridine-palladium dichloride (16) and 4,5-bis(dipheny lphosphino)acridine-molybdenum tricarbonyl (17), compound 3 is capable of acting as a tridentate PNP ligand which coordinates transition met als in an approximately ''T-shaped'' planar coordination geometry. Sin gle crystal X-ray structure analyses are reported for 3 and 17. (C) 19 98 Elsevier Science Ltd. All rights reserved.