PERI-INTERACTIONS IN NAPHTHALENES, 2¹. SUBSTITUENT EFFECTS IN (8-DIMETHYLAMINO-NAPHTH-1-YL)- AND [2-DIMETHYLAMINO-METHYL)PHENYL] - PHOSPHINES ON THE³¹P-NMR SIGNAL POSITIONS

Abstract

Contrary to claims in the literature, the "P NMR signal positions of ortho-dimethylaminomethyl-substituted triarylphosphines do not provide evidence for hypercoordination at phosphorus; the observed highfield shifts relative to triphenylphosphine are rather due to the ortho-effect. In (8-dimethylamino-naphth-I -yl)phosphines, the signal positions similar to that of triphenylphosphine are the result of the highfield orrho-effect and a lowfield peri-substituent effect of about the same magnitude whose nature remains to be explored.

Peri‐Interactions in 8‐Diphenylphosphino‐1‐bromonaphthalene, 6‐Diphenylphosphino‐5‐bromoacenaphthene, and Derivatives

“…The subsequent reaction with diphenylchlorophosphine afforded 8-diphenylphosphino-1bromonaphthalene, 1-Br-8-(Ph 2 P)-Nap (1a), and 6-diphenylphosphino-5-bromonaphthalene, 6-Br-5-(Ph 2 P)-Ace (1b), in 51% and 54% yield (Scheme 2). We note that the preparation of 1a has previously been reported, [65,85] but apart from the 31 As expected, the phenyl group attached to the Se atom does not increase the sterical strain, as it is not directed towards the peri-region. Due to the ethylene bridge on the opposite side of the peri-interaction, the bay angle C(10)-C(19)-C(18) is always larger in the acenaphthene than in naphthalene species.…”

Peptidyl Succinimidyl Peptides as Taspase 1 Inhibitors

“…We note that the preparation of 1a has previously been reported65,85 but apart from the 31 P NMR chemical shift, neither spectroscopic nor structural data were reported at the time. In 1a and 1b , both substituents in the peri ‐positions may be susceptible to undergo chemical transformations.…”

Naphthalene and Related Systems peri‐Substituted by Group 15 and 16 Elements

“…Other arguments, such as high-field shift of the phosphorus NMR signal on intramolecular DAN coordination (or its absence) were questioned by Schiemenz; additional support for non-existence of the dative bond was found in analysing the J(CH) coupling constants of NMe 2 groups [64] or the study of NMR properties of protonated DAN-phosphines. [62] During these comparative studies a range of DAN-phosphines and related compounds were synthesized by Schiemenz (Scheme 38) [62,63,[67][68][69] and (Scheme 34). [55] Schiemenz concluded that under favourable conditions DAN-phosphorus compounds can form dative N!P bonds and hexacoordination at phosphorus can occur, an example of this is molecule 64 (Scheme 34).…”