Die Chemie von niedrig koordiniertem Phosphor

By employing strategies based on frustrated Lewis pair chemistry, new routes to phosphino-phosphonium cations and zwitterions have been developed. B(C(6)F(5))(3) is shown to react with H(2) and P(2)tBu(4) to effect heterolytic hydrogen activation yielding the phosphino-phosphonium borate salt [(tBu(2)P)PHtBu(2)] [HB(C(6)F(5))(3)] (1). Alternatively, alkenylphosphino-phosphonium borate zwitterions are accessible by reaction of B(C(6)F(5))(3) and PhC[triple chemical bond]CH with P(2)Ph(4), P(4)Cy(4), or P(5)Ph(5) affording the species [(Ph(2)P)P(Ph)(2)C(Ph)=C(H)B(C(6)F(5))(3)] (2), [(P(3)Cy(3))P(Cy)C(Ph)=C(H)B(C(6)F(5))(3)] (3), and [(P(4)Ph(4))P(Ph)C(Ph)=C(H)B(C(6)F(5))(3)] (4). A related phosphino-phosphonium borate species-[(Ph(4)P(4))P(Ph)C(6)F(4)B(F)(C(6)F(5))(2)] (5) is also isolated from the thermolysis of B(C(6)F(5))(3) and P(5)Ph(5).

New Strategies to Phosphino–Phosphonium Cations and Zwitterions

Geier

Dureen

Ouyang

et al. 2010

A Phosphorus Analogue of p‐Quinodimethane with a Planar P₄ Ring: A Metal‐Free Diphosphorus Source

Rottschäfer

Neumann

Stammler

et al. 2019

Para-quinodimethane (pQDM) is af undamental structural component in many p-conjugated organic molecules andm aterials. The incorporation of phosphorus atom into p-conjugated frameworks offersu nique opportunitiesf or controlling the properties of derived species. A phosphorus analogueo fp-quinodimethane (pQDM), (IPrC) 2 P 4 [5,I Pr = C{N(Ar)CH 2 } 2 ;A r= 2,6-iPr 2 C 6 H 3 ]f eaturinga planar P 4 ring, was readily accessible by KC 8 -reduction of (IPrC)(PCl 2 ) 2 (2). Base-mediatedC ÀHf unctionalizationo f IPrCH 2 (1)w ith PCl 3 afforded 2.T he formation of 5 was expected to occur through ad imerization of the transient 3H-diphosphirene (IPrC)P 2 (4), which was theoretically suggested to have an intermediate diradical character.C ompound 5 underwentp hoto-induced ring-contraction reaction to form the singlet diradicaloid (IPrCP) 2 VI and white phosphorus (P 4 ). Thef ormationo fa nd VI andP 4 suggested the formald iphosphorus( P 2 )e limination from 5.

1,3‐Diphosphacyclobutene Cobalt Complexes

Rödl

Schwedtmann

Weigand

et al. 2019

The synthesis andc haracterization of rare 1,3-diphosphacyclobutene transition-metal complexes is described. Reactions of the cobalt-hydride complex [Co(P 2 C 2 tBu 2 ) 2 H] (G)w ith nBuLi, tBuLi, or PhLi afforded [Li-(solv) x {Co(h 3 -P 2 C 2 tBu 2 HR)(h 4 -P 2 C 2 tBu 2 )}] (1:R = nBu, (solv) x = (Et 2 O) 2 ; 2:R = tBu, (solv) x = (thf) 2 ; 3:R = Ph, (solv) x = (Et 2 O)(thf) 2 ), with an h 3 -coordinated 1,3-diphosphacyclobutene ligand as ar esult of organyl-anion attacka to ne of the phosphorus atoms of the bis(1,3-diphosphacyclobutadiene) backbone. In contrast to the reactions with PhLi, the arylmagnesium compounds p-tolyl magnesium chloride and p-fluorophenyl magnesiumbromide deprotonate [Co(P 2 C 2 tBu 2 ) 2 H] to give the magnesium salt [Mg(MeCN) 6 ] [Co(h 4 -P 2 C 2 tBu 2 ) 2 ] 2 (4), whichc ontainsabis(1,3-diphosphacyclobutadiene)-cobaltatea nion. The [Co(h 4 -P 2 C 2 tBu 2 ) 2 ] À anions are well separated from the octahedral [Mg(MeCN) 6 ] 2 + cationi nt he molecular structure of 4.C ompound 1 reacts with Me 3 SiCl to give neutral [Co(h 3 -P 2 C 2 tBu 2 HnBu)(h 4 -P 2 C 2 tBu 2 SiMe 3 )] (5,5 2% yield) with an SiMe 3 group attached to one of the Pa toms of the previously unfunctionalized backbone. Figure 1. Previously reported derivatizations of 1,3-diphosphacyclobutadiene complexes through the attack of nucleophiles. [7][8][9] [a] C. Rçdl,P rof. Dr.R.W olf Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.Figure 2. a) FunctionalizationofF by treatment with electrophiles (previous work): i) HCl·Et 2 O;ii)MeI ;iii)Ph 2 PCl ;b)synthesis of anionic 1,3-diphosphacyclobutenec omplexes 1-3 by addition of lithium organyls to G (this work).