1,8-BIS(PHOSPHINO)NAPHTHALENES - SYNTHESIS AND MOLECULAR-STRUCTURES

A series of 1, 8-bis(phosphino)naphthalenes 2 was prepared by treating 1, 8-dilithionaphthalene with the appropriate chloro- or bromophosphi nes RR'PX; R, R' = Me (for 2a), iPr (for 2c), Cy (for 2d), Ph (for 2f) ; R = tBu, R' = Ph (for 2e) (X = Cl) and R, R' = Et; X = Br (for 2b). The resulting bisphosphines were characterized by NMR spectroscopy, ma ss spectrometry, and elemental analysis. X-ray crystal structure analy ses were performed for 1, 8-bis(diisopropylphosphino)naphthalene (2c), 1, 8-bis(dicyclohexylphosphino)naphthalene (2d), and rac-1, 8-bis(ter t-butylphenylphosphino)naphthalene (2e). In each case, the proximity o f the PR2 groups leads to distortion the main feature of which is the out-of-plane displacement of the P atoms. However, the distortions ari sing from the bulky PCy2 groups in 2d were remarkably small. (C) 1997 John Wiley & Sons, Inc.