Dipnictogen f-Element Chemistry: A Diphosphorus Uranium Complex

Abstract

The first isolation and structural characterization of an f-element dinitrogen complex was reported in 1988, but an f-element complex with the first heavier group 15 homologue diphosphorus has to date remained unknown. Here, we report the synthesis of a side-on bound diphosphorus complex of uranium­(IV) using a 7λ3-(dimethyl­amino)­phospha­dibenzo­norborna­diene-mediated P atom transfer approach. Experimental and computational characterization reveals that the diphosphorus ligand is activated to its dianionic (P2)2– form and that in-plane U–P π-bonding dominates the bonding of the U­(μ-η2:η2-P2)U unit, which is supplemented by a weak U–P interaction of δ symmetry. A preliminary reactivity study demonstrates conversion of this diphosphorus complex to unprecedented uranium cyclo-P3 complexes, suggesting in situ generation of transient, reactive phosphido species.

Taming Phosphorus Mononitride (PN)

“…NMR spectra were obtained on Bruker Avance 400, 401 or Bruker Neo 500 instruments equipped with Magnex Scientific superconducting magnets. 1 H and 13 C NMR spectra were referenced to residual protiated solvent resonances; 54 31 P NMR spectra were referenced externally to 85% aqueous H3PO4 (δ = 0 ppm). Elemental analyses were performed by Midwest Microlab (Indianapolis, IN).…”

“…1 H NMR (benzene-d6, 400 MHz, 25 °C) δ 7.41 (m, 2H), 7.33 (m, 2H), 7.17(m, 2H), 6.98 (m, 2H), 4.06 (d, 2H, 2 JPH = 12.6 Hz, H4) ppm. 13 C{ 1 H} NMR (benzene-d6, 126 MHz, 25 °C) δ 145.9 (d, J = 3.1 Hz), 141.7 (d, J = 22.5 Hz), 126.5, 125.2, 124.5, 123.7 (d, J = 3.5 Hz), 56.8 (d, J = 18.9 Hz) ppm. 31 P{ 1 H} NMR (benzene-d6, 162 MHz, 25 °C) δ 181 ppm.…”

“…1 H NMR (diethyl ether (solvent suppressed), 500 MHz, 25 °C) δ 8.27 (m, 8H, BArF24), 8.10 (m, found 14H, expected 16H), 8.03 (m, 4 H), 7.91 (m, 4H, BArF24), 2.96 (m, 2H), 2.81 (m, 2H), 1.92 (s, 15H) ppm. 13 C{ 1 H} NMR (diethyl ether, 126 MHz, 25 °C) δ 162.1 (q, J = 50.0 Hz), 135.1 (m), 133.7 (m), 132.6 (m), 13.6 (d, J= 29.6 Hz), 130.9 (m), 129.6 (m), 125.0 (q, J = 272.0 Hz), 117.5 (m), 92.2 , 28.7, 9.0 ppm. 31…”

“…9 Klapötke et al described with P3N21 the smallest structurally characterized discrete binary PN molecule so far. 10 The stabilization and activation of dipnictogens, e.g., N2, 11 P2, 12,13 and just recently PN 14 is still an ongoing endeavor in inorganic chemistry. Due to its high reactivity and the absence of a suitable molecular precursor for a mild release of PN, molecules containing embedded phosphorus mononitride units have been synthesized and stabilized in various fashions, e.g., N-heterocyclic carbenes, 15 anthracene (APNA), 16 or cyclo-tetraphosphazene.…”

Trendbericht Anorganik 2022 Teil 2: Nebengruppen und Koordinationschemie, Bioanorganik und mehr

“…Da die zu untersuchenden Kerne mit den ungepaarten Elektronen interagieren, sind Signale oft stark verbreitert, und im Vergleich zu diamagnetischen Verbindungen liegen die chemischen Verschiebungen weit abseits. Gade und Mitarbeiter:innen haben nun für einen quadratisch-planaren Eisenhydridkomplex mit phosphanbasiertem Pinzettenliganden ein 31 P-Signal mit der extremen Verschiebung von mehr als 10 000 ppm detektiert.…”