Terminal Parent Phosphanide and Phosphinidene Complexes of Zirconium(IV)

Abstract

Well-defined transition-metal phosphinidene complexes (L n M = PR) are of interest owing to ad esire to better understand their bonding and PR-group transfer chemistry. [1,2] However, although such complexes were first reported three decades ago, [3] they remain ar elatively rare class of metal-ligand multiple bond. This relative paucity reflects the inherent nature of the phosphinidene functional group,which as af ree moiety is very reactive due to the P-triplet ground state and unsaturated valence shell.[4] Stabilization of aphosphinidene by metal-coordination is an attractive strategy, [1] but normally also demands as terically bulky group at phosphorus to kinetically stabilize the M=PR linkage.Indeed, it is notable that under ambient conditions all isolable transition-metal phosphinidene complexes exhibit sterically demanding Rg roups to kinetically protect these vulnerable M=PR bonds; [3,[5][6][7][8][9] in abroader sense the only exceptions are where fundamental, elegant species such as H 2 M = PH (M = Ti,Z r, and Hf) have been prepared and spectroscopically observed under cryogenic conditions.[10] Early transitionmetal phosphinidene complexes are perhaps the most developed of all metal-phosphinidenes,s oi ti ss urprising that an early transition-metal parent phosphinidene has not yet been realized under ambient conditions.Recently,a spart of our work on actinide-ligand multiple bonds, [11] we reported uranium and thorium phosphinidene complexes using the parent phosphinidene (HP) 2À , [12] despite the large triplet-singlet energy gap of approximately 22 kcal mol À1 for free PH, [4g] which had previously only been seldom observed as af leeting spectroscopic intermediate or probed theoretically.[4] Those two actinide complexes are the only two M = PH complexes yet isolated outside cryogenic spectroscopic experiments,a nd were supported by the very sterically demanding triamidoamine ligand N(CH 2 CH 2 NSiPr

Actinide Pnictinidene Chemistry: A Terminal Thorium Parent‐Arsinidene Complex Stabilised by a Super‐Bulky Triamidoamine Ligand

“…These metrics were determined by a combination of initial atom location in the Fourier difference map combined with crystallographic refinement guided by DFT calculations. Acute M−Pn−H angles (≈59–64°) have previously been found for H 2 M=PnH (M=Ti, Zr, Hf, Th, U) [7a,b] in cryogenic matrix isolation experiments and in structurally authenticated [Zr(Tren DMBS )(PH)][K(B15C5) 2 ] (Zr−P−H angle: 66.7(8)°; Tren DMBS ={N(CH 2 CH 2 NSiMe 2 Bu t ) 3 } 3− ), [10] [Th(Tren TIPS )(PH)][Na(12C4) 2 ] (Th−P−H angle: 67.45(8)°), [11b] A (Th−As−H angle: 79.1(2)°), [20] but this interaction is relaxed in [U(Tren TIPS )(PH)][K(B15C5) 2 ] (U−P−H angle: 118.8(9)°) [11c] and [U(Tren TIPS )(AsH)][K(B15C5) 2 ] (U−As−H angle: 90(6)°) [13] . We suggest this variance may depend on electronic factors, such as how electron rich M is (e.g.…”

“…Structurally authenticated molecules with terminal (i.e. the PnR group is bound to only one metal) PnH groups are sparse across the whole Periodic Table, with a handful of terminal parent phosphinidene (M=PH) compounds known for p‐, [9] d‐, [10] and f‐blocks [11] . Terminal arsinidene (M=AsR) congeners have emerged for p‐ [12] and f‐block [13] derivatives recently, but M=AsH remains unknown for the d‐block; indeed, only five M=AsR d‐block complexes have been crystallographically characterised in the past 28 years [14–17] .…”

Tungsten Hydride Phosphorus- and Arsenic-Bearing Molecules with Double and Triple W–P and W–As Bonds

“…21 Terminal parent phosphanide and phosphinidene complexes of zirconium(IV) have been prepared recently. 22 Tungsten phosphinidene and arsinidene complexes react to form four-membered heterocycles. 23 The reactivity of a phosphanylphosphinidene complex of tungsten(VI) with phosphines has also been investigated.…”

Synthesis and reactivity of low-valent uranium and neptunium complexes

“…The chemistry of low-valent actinide has been of great interest due to the isolation of actinides in rare divalent oxidation states, [111][112][113][114][115][116] small molecule activation, 133,134 and examining metal-ligand bonding. 149,[163][164][165][166][167][168][169] This is especially true of U(III), a powerful reducing agent. 170 However, when one traverses the actinide series, there is a propensity to favor the trivalent oxidation state, much like their lanthanide counterparts.…”