1,8-bis(phosphanyl)naphthalenes: 1,8-bis[(diethylamino)phosphanyl]naphthalene, 1,8-bis(dichlorophosphanyl)naphthalene, and 1,3-dichloro-2,3-dihydro-1,3-dioxo-2-oxa-1,3-diphosphaphenalene

1,8-Dilithionaphthalene 1 reacted with bis(diethylamino)chlorophosphane to form 1,8-bis[(diethylamino)phosphanyl]naphthalene 2, whose structure was confirmed by X-ray crystal structure analysis; there are two independent molecules, in which the P(NEt2)(2) groups adopt an eclipsed conformation. Reaction of 2 with gaseous HCl gave in low yield 1,8-bis(dichlorophosphanyl)naphthalene 3, which was characterized by H-1- and P-31-NMR spectroscopy, mass spectrometry and elemental analysis. Attempted recrystallization of 3 led to oxidative hydrolysis which furnished 4, an anhydride of a bis(chlorophosphonic acid), whose structure was elucidated by X-ray crystal structure analysis. The geometry of 4 reveals a relief of strain from the bis(aminophosphane) 2; the naphthalene groups are less distorted and the P atoms are displaced less far from the naphthalene best plane.