Rearrangement of a P 4 Butterfly Complex—The Formation of a Homoleptic Phosphorus–Iron Sandwich Complex

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The versatile coordination behavior of the P4 butterfly complex [{Cp*Cr(CO)3}2(μ,η1:1‐P4)] (1) towards Lewis acidic pentacarbonyl compounds of Cr, Mo and W is reported. The reaction of 1 with [W(CO)4(nbd)] (nbd=norbornadiene) yields the complex [{Cp*Cr(CO)3}2(μ3,η1:1:1:1‐P4){W(CO)4}] (2) in which 1 serves as a chelating P4 butterfly ligand. In contrast, reactions of 1 with [M(CO)4(nbd)] (M=Cr (a), Mo (b)) result in the step‐wise formation of [{Cp*Cr(CO)2}2(μ3,η3:1:1‐P4){M(CO)5}] (3 a,b) and [{Cp*Cr(CO)2}2‐(μ4,η3:1:1:1‐P4){M(CO)5}2] (4 a,b) which contain a folded cyclo‐P4 unit. Complex 4 a undergoes an unprecedented P1/P3‐fragmentation yielding the cyclo‐P3 complex [Cp*Cr(CO)2(η3‐P3)] (5) and the as yet unknown phosphinidene complex [Cp*Cr(CO)2{Cr(CO)5}2(μ3‐P)] (6). The identity of 6 is confirmed by spectroscopic methods and by the in situ formation of [{Cp*Cr(CO)2(tBuNC)}P{Cr(CO)5}2(tBuNC)] (7). DFT calculations throw light on the bonding situation of the reported products.

Section: Methodsmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The Butterfly Complex [{Cp*Cr(CO)₃}₂(μ,η^1:1‐P₄)] as a Versatile Ligand and Its Unexpected P₁/P₃ Fragmentation

Grünbauer

Baláȥs

Scheer

2020

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“…Moreover, the cationic derivatives of type A show an interesting reactivity towards water, unexpectedly leading to the formation of PH 3 , P 2 H 4 , and other phosphorus‐containing products such as PO n H m species, showing a different reaction behavior in comparison to free P 4 ,. Furthermore, the reductive degradation of the P 4 tetrahedron leads to a stepwise P 4 transformation, revealing as the next step either the P 4 2− species, mono‐ or dicoordinated by transition‐metal fragments, or the square planar cyclo ‐P 4 2− species as an “end‐deck” (type D ), a middle deck in a triple‐decker sandwich complex (type F ), or, as recently reported, as end‐decks in homoleptic iron sandwich complexes (type G ) …”

Section: Methodsmentioning

confidence: 99%

“…[4b,h, 7] Furthermore, the reductive degradationo ft he P 4 tetrahedron leads to as tepwise P 4 transformation,r evealing as the next step either the P 4 2À species, monoor dicoordinated by transition-metal fragments, [5] or the square planar cyclo-P 4 2À speciesa sa n" enddeck" (type D), [8] am iddle deck in at riple-decker sandwich complex( type F), [9] or,a sr ecently reported, as end-decks in homoleptic iron sandwich complexes (type G). [10] As ar epresentative approach, the triple-decker complex [(Cp'''Co) 2 (m-C 7 H 8 )] (1,C p ''' = C 5 H 2 -1,2,4-tBu 3 ), [11] which exists in solutiona sa14-valence-electron (VE) [Cp'''Co] fragment, enables the reaction with P 4 under very mild conditions. Tuning both the stoichiometry and the reaction conditions of 1 with free white phosphorus, different polyphosphorus (P n )a ggregates (n 29) and the binuclear derivative[ (Cp'''Co) 2 (m,h 2:2 -P 2 ) 2 ] were obtained.…”

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confidence: 99%

Metal‐Assisted Opening of Intact P₄ Tetrahedra

Modl

Heinl

Baláȥs

et al. 2019

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The reactivity of ruthenium and manganese complexes bearing intact white phosphorus in the coordination sphere was investigated towards the low‐valent transition‐metal species [Cp′′′Co] (Cp′′′=η5‐C5H2‐1,2,4‐tBu3) and [L0M] (L0=CH[CHN(2,6‐Me2C6H3)]2; M=Fe, Co). Remarkably, and irrespective of the metal species, the reaction proceeds by the selective cleavage of two P–P edges and the formation of a square‐planar cyclo‐P4 ligand. The reaction products [{CpRu(PPh3)2}{CoCp′′′}(μ,η1:4‐P4)][CF3SO3] (5), [{CpBIGMn(CO)2}2{CoCp′′′}(μ,η1:1:4‐P4)] (6) and [{CpBIGMn(CO)2}2{ML0}(μ,η1:1:4‐P4)] (CpBIG=C5(C6H4nBu)5; L0=CH[CHN(2,6‐Me2C6H3)]2; M=Fe (7 a), Co (7 b)), respectively, were fully characterized by single‐crystal X‐ray diffraction and spectroscopic methods. The electronic structure of the cyclo‐P4 ligand in the complexes 5–7 is best described as a π‐delocalized P42− system, which is further stabilized by two and three metal moieties, respectively. DFT calculations envisaged a potential intermediate in the reaction to form 5, in which a quasi‐butterfly‐shaped P4 moiety bridges the two metals and behaves as an η3‐coordinated ligand towards the cobalt center.

Coordination Behavior of a P₄‐Butterfly Complex towards Transition Metal Lewis Acids: Preservation versus Rearrangement

Müller

Scheer

2021

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The reactivity of the P4 butterfly complex [{Cp’’’Fe(CO)2}2(μ,η1:1‐P4)] (1, Cp’’’=η5‐C5H2tBu3) towards divalent Co, Ni and Zn salts is investigated. The reaction with the bromide salts leads to [{Cp’’’Fe(CO)2}2(μ3,η2:1:1‐P4){MBr2}] (M=Co (2Co), Ni (2Ni), Zn (2Zn)) in which the P4 butterfly scaffold is preserved. The use of the weakly ligated Co complex [Co(NCCH3)6][SbF6]2, results in the formation of [{(Cp’’’Fe(CO)2)2(μ3,η4:1:1‐P4)}2Co][SbF6]3 (3), which represents the second example of a homoleptic‐like octaphospha‐metalla‐sandwich complex. The formation of the threefold positively charged complex 3 occurs via redox processes, which among others also enables the formation of [{Cp’’’Fe(CO)2}4(μ5,η4:1:1:1:1‐P8){Co(CO)2}][SbF6] (4), bearing a rare octaphosphabicyclo[3.3.0]octane unit as a ligand. On the other hand, the reaction with [Zn(NCCH3)4][PF6]2 yields the spiro complex [{(Cp’’’Fe(CO)2)2(μ3,η2:1:1‐P4)}2Zn][PF6]2 (5) under preservation of the initial structural motif.