A ³¹P NMR STUDY OF THE WATER SOLUBLE DERIVATIVES OF 1,3,5-TRIAZA-7-PHOSPHAADAMANTANE (PTA)

The dual role of cis-[RuCl2(dmso)4] in the synthesis of new water-soluble Ru(II)–phosphane complexes and in the catalysis of redox isomerization of allylic alcohols in aqueous–organic biphasic systems

“…Literature values of the pKa of pta vary in the range of 5.63-6.0, [7,[36][37][38] so the protonation of coordinated pta in 2 takes place under more acidic conditions relative to the free ligand.…”

“…The water-soluble phosphane ligands, mtppms, [50] mtppts (mtppts = P(C6H4-3-SO3Na)3), [51] pta, [52] (pta-Bn)Cl (1-benzyl-1-azonia-3,5-diaza-7-phosphaadamantyl chloride), [36] and cis-[RuCl2(dmso)4] (1), [8] were prepared according to the literature. (ptaMe)CF3SO3 [25] was kindly supplied by Prof. A. Romerosa (U. Almería, Spain).…”

Intramolecular hydroamination of alkynylamines in aqueous media catalyzed by platinum(II) 1,3,5-triaza-7-phosphaadamantane (PTA) complexes

“…Compounds 1, 2, and 3 were active catalysts in the intramolecular hydroamination of 4-pentyn-1-amine in water. This is the first reported study of this metal-mediated transformation in aqueous media.The water-soluble phosphine 1,3,5-triaza-7-phosphaadamantane (PTA) has recently received quite a bit of attention because of its ease of preparation [1], its remarkably small cone angle (103°) [2], and its resistance to oxidation [3]. To date, PTA complexes of Cr, Mo, W, Re, Fe, Ru, Rh, Ir, Ni, Pd, Pt, Cu, Au, and Hg have been prepared [4].…”

Synthesis and structure of stable water-soluble phosphonium alkanoate zwitterions derived from 1,3,5-triaza-7-phosphaadamantane

“…Among other properties, similarity of pta to urotropine is shown also by the finding that dilute aqueous acids protonate one of the nitrogens of both compounds [20], while no P-protonated pta is known. Furthermore, reaction of both urotropine and pta with alkyl halides yield N-alkylated (azonia) products [18].…”

“…Namely, the lone electron pairs of the nitrogens (N) are donated to the unoccupied P-C and C-N bonds leading to increased stability of the molecule. It is known that on the action of strong acids (such as HCl) pta is protonated on one of its nitrogen atoms [20]. According to the calculations, protonation of pta on N 1 results in distortion in the electron density distribution and the donor-acceptor interactions of the protonated nitrogen disappear (Table 3).…”