Synthesis and1H-,15N-,31P-,183W-Multinuclear Magnetic Resonance Study of the Cyclotriphosphazenes [N3P3(dobp)2(OC5H4N-4)2] and [N3P3(dobp)(OC5H4N-4)4] and Their W(CO)5 Complexes (dobp = 2,2′-dioxybiphenyl)

Abstract

The reactions of [N3P3(dobp)2Cl2] and [N3P3(dobp)Cl4] with a mixture of HOC5H4N‐4 and K2CO3 in acetone give the cyclotriphosphazenes [N3P3(dobp)2(OC5H4N‐4)2] and [N3P3(dobp)(OC5H4N‐4)4], respectively. These compounds react with [W(MeOH)(CO)5] in methanol to give mixtures of the polymetallic complexes [N3P3(dobp)2(OC5H4N‐4)2{W(CO)5}x] (x = 1, 2) and [N3P3(dobp)(OC5H4N‐4)4{W(CO)5}x] (x = 1–4), which are unstable in solution, slowly undergoing loss of the pentacarbonyl moiety. A complete characterization by multinuclear 1H, 15N, 31P, 183W magnetic resonance has revealed that the complexation of the N atom of one 4‐oxypyridine ligand by the W(CO)5 fragment has a measurable effect on other parts of the phosphazene molecule very far away from the coordination site. The changes observed in δ183W have been used to identify the components in mixtures of compounds incorporating different numbers of tungsten atoms in the molecule. The characterization of less sensitive nuclei has been accomplished by means of indirect detection methods.

Small Molecule and High Polymeric Phosphazenes Containing Oxypyridine Side Groups and Their Organometallic Derivatives: Useful Precursors for Metal Nanostructured Materials

“…In the NMR spectrum, of special significance was the effect on the o-H signals of the pyridine groups, which change from 7.89 ppm in free HOC 5 H 4 N to 8.47 ppm upon coordination. However, and as found in other MLn systems, where L is a ligand containing pyridine, 16 partial dissociation of the pyridinemetal bond occurred. In fact, other signals at 7.71 ppm corresponding to o-H of the uncoordinated 4-hydroxypyridine were seen.…”

“…Thus, similarly to what has been found in other phosphazenes containing oxypyridine side groups, 16 dissociation of the metal fragment occurred:…”

“…Thus, similarly to what has been found in other phosphazenes containing oxypyridine side groups, dissociation of the metal fragment occurred: Using 31 P NMR data, an equilibrium constant of K = 6.4 was estimated. As mentioned above, the ν(CO) bands in CH 2 Cl 2 solution are split compared to those of ν(CO) in the solid state, suggesting the presence of two species: one containing the coordinated W(CO) 5 unit and the other one the free W(CO) 5 .…”

Metallocyclo‐ and Polyphosphazenes Containing Gold or Silver: Thermolytic Transformation into Nanostructured Materials

“…As previously observed in the analogous cyclotriphosphazene with W(CO) 5 that were synthesized by Carriedo and co‐workers,21, 22 IR spectra of all of these complexes clearly show the coordination of the metal fragments Au(C 6 F 5 ), Au(C 6 F 5 ) 3 , Au(PPh 3 ), or Ag(OTf)PPh 2 R to the pendant pyridines. Thus, the strong oxypyridine band at 1582 cm −1 of the starting cyclophosphazene ( I ) disappeared after coordination of the metal and a new band at approximately 1600 cm −1 appeared (see the Experimental Section for details), which was also noted in the IR spectrum of the tungsten complex with the analogous polymer 22.…”

Diastereoselective Ortho Lithiation of Phosphinimidic Amides: A Multinuclear Magnetic Resonance and Computational Study

“…The 15 N chemical shifts are consistent with those recently described for intermediate 8 and previous data reported in the literature for similar phosphazenes. 27 As was expected, the 2D 7 Li, 31 P-HMQC NMR experiment 28 showed correlation of both lithiums with the phosphorus. All this information revealed that the dilithiated intermediate 10 consists of a N,C ortho and O,N α double chelate, in which the phosphazenyl nitrogen stabilizes the ortho-lithiated position whereas the carboxymethyl fragment does the same with the lithium amide.…”