Crystalline Diuranium Phosphinidiide and μ‐Phosphido Complexes with Symmetric and Asymmetric UPU Cores

Abstract

Reaction of [U(TrenTIPS)(PH2)] (1, TrenTIPS=N(CH2CH2NSiPri 3)3) with C6H5CH2K and [U(TrenTIPS)(THF)][BPh4] (2) afforded a rare diuranium parent phosphinidiide complex [{U(TrenTIPS)}2(μ‐PH)] (3). Treatment of 3 with C6H5CH2K and two equivalents of benzo‐15‐crown‐5 ether (B15C5) gave the diuranium μ‐phosphido complex [{U(TrenTIPS)}2(μ‐P)][K(B15C5)2] (4). Alternatively, reaction of [U(TrenTIPS)(PH)][Na(12C4)2] (5, 12C4=12‐crown‐4 ether) with [U{N(CH2CH2NSiMe2But)2CH2CH2NSi(Me)(CH2)(But)}] (6) produced the diuranium μ‐phosphido complex [{U(TrenTIPS)}(μ‐P){U(TrenDMBS)}][Na(12C4)2] [7, TrenDMBS=N(CH2CH2NSiMe2But)3]. Compounds 4 and 7 are unprecedented examples of uranium phosphido complexes outside of matrix isolation studies, and they rapidly decompose in solution underscoring the paucity of uranium phosphido complexes. Interestingly, 4 and 7 feature symmetric and asymmetric UPU cores, respectively, reflecting their differing steric profiles.

A μ‐Phosphido Diiron Dumbbell in Multiple Oxidation States

“…The Mössbauer spectrum of 3 shows a quadruple doublet with parameters δ =0.01 mm s −1 and Δ E Q =1.94 mm s −1 , quite similar to those of [(LFe) 2 (μ‐O)](OTf) 4 ( δ =0.04 mm s −1 and Δ E Q =2.56 mm s −1 ) and indicative of ferric complexes of the tetracarbene macrocycle L . Although μ‐oxido diiron(III) complexes are abundant and a number of μ‐phosphido complexes have been reported, mainly for 4d and 5d metals, the Fe‐(μ‐P)‐Fe core with a “naked” bridging phosphido ligand is unprecedented.…”

Actinide–Pnictide (An−Pn) Bonds Spanning Non‐Metal, Metalloid, and Metal Combinations (An=U, Th; Pn=P, As, Sb, Bi)

“…This is clearly a delicate balance of sterics, since for the larger thorium neither Tren DMBS nor Tren TIPS can stabilise Th−Bi linkages. Such a fine balance of metal/ligand size ratio has been found previously with respect to μ‐phosphido linkages where thorium–Tren TIPS gives stable ThPTh linkages but uranium–Tren TIPS results in UPU linkages that readily decompose ,…”

Thorium(IV) and Uranium(IV) Phosphaazaallenes

“…For example, phosphaalkenes, P=C, have attracted interest for building blocks in organophosphorus chemistry [1][2][3], ligands to transition metal complexes [4,5], as well as potential applications as functional materials [6][7][8][9][10]. After nearly 20 years of dormancy [11][12][13][14][15], actinide-phosphorus has received greater attention recently [16][17][18][19] with researchers examining similarities and differences in the molecular and electronic structure of its more studied congener, nitrogen. Our interest in actinide-phosphido complexes has been on investigating small molecule reactivity.…”