1,3‐Diphosphacyclobutene Cobalt Complexes

Abstract

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).

Low-oxidation state cobalt–magnesium complexes: ion-pairing and reactivity

“…Although the coordination of a heterometal to the diphosphacyclobutadiene ring in metal sandwich complexes is a common motif, complexes 4 and 5 are the first instances of such heterometallic compounds involving a group 2 metal. 17 …”

Low-Valent Transition Metalate Anions in Synthesis, Small Molecule Activation, and Catalysis

“…1095), in which both P 2 C 2 rings have been functionalized. 652 In addition, oxygen-containing substrates (ethers, epoxides, lactones, aldehydes, ketones or isocyanates) insert into the Si−P bond of the silyl-derivative 1091, thereby generating new P−O bonds (1096, Scheme 154, bottom right). 653 The phosphorus atom on the diphosphacyclobutadiene ligands of 189−191 can further coordinate other metal centers, acting as metalloligands, to obtain oligonuclear complexes.…”

“…The hydride complex 1087 reacts with lithium organyls (R′Li, R′ = Ph, n Bu, t Bu) to generate rare 1,3-diphospha­cyclobutene complexes [R′ = Ph ( 1092 ), n Bu ( 1093 ), t Bu ( 1094 ); Scheme , bottom left-center]. Reaction of the anionic complex 1093 with Me 3 SiCl led to the quantitative formation of [Co­(η 3 -P 2 C 2 t Bu 2 H n Bu)­(η 4 -P 2 C 2 t Bu 2 SiMe 3 )] ( 1095 ), in which both P 2 C 2 rings have been functionalized . In addition, oxygen-containing substrates (ethers, epoxides, lactones, aldehydes, ketones or isocyanates) insert into the Si–P bond of the silyl-derivative 1091 , thereby generating new P–O bonds ( 1096 , Scheme , bottom right) …”

Synthesis of a carborane-substituted bis(phosphanido) cobaltate(i), ligand substitution, and unusual P4fragmentation

“…We have previously highlighted how the dimerisation of phosphaalkynes in the coordination sphere of low-valent Co complexes can be used to access coordinatively and chemically versatile complexes of 1,3-diphosphabutadienes. [33][34][35] Thus, the reaction between [K(18-c-6)(thf)][rac-1] and tert-butyl phosphaalkyne, tBuCP, was investigated. As hoped, this leads to the clean and exclusive formation of the 16 VE complex [K (18-…”