The synthesis and structural characterization of the first coordination compounds of bis(diphosphacyclobutadiene) cobaltate anions [M(P(2)(2)R(2))(2)](-) is described. Reactions of the new potassium salts [K(thf)(3){Co(η(4)-P(2)C(2)tPent(2))(2)}] (1) and [K(thf)(4){Co(η(4)-P(2)C(2)Ad(2))(2)}] (2) with [AuCl(tht)] (tht = tetrahydrothiophene), [AuCl(PPh(3))] and Ag[SbF(6)] afforded the complexes [Au{Co(P(2)C(2)tPent(2))(2)}(PMe(3))(2)] (3), [Au{Co(P(2)C(2)Ad(2))(2)}](x) (4), [Ag{Co(P(2)C(2)Ad(2))(2)}](x) (5), [Au(PMe(3))(4)][Au{Co(P(2)C(2)Ad(2))(2)}(2)] (6), [K([18]crown-6)(thf)(2)][Au{Co(P(2)C(2)Ad(2))(2)}(2)] (7), and [K([18]crown-6)(thf)(2)][M{Co(P(2)C(2)Ad(2))(2)}(2)] (8: M = Au 9: M = Ag) in moderate yields. The molecular structures of 2 and 3, and 6-9 were elucidated by X-ray crystallography. Complexes 4-9 were thoroughly characterized by (31)P and (13)C solid state NMR spectroscopy. The complexes [Au{Co(P(2)C(2)Ad(2))(2)}](x) (4) and [Ag{Co(P(2)C(2)Ad(2))(2)}](x) (5) exist as coordination polymers in the solid state. The linking mode between the monomeric units in the polymers is deduced. The soluble complexes 1-3, 6, and 7 were studied by multinuclear (1)H-, (31)P{(1)H}-, and (13)C{(1)H} NMR spectroscopy in solution. Variable temperature NMR measurements of 3 and 6 in deuterated THF reveal the formation of equilibria between the ionic species [Au(PMe(3))(4)](+), [Au(PMe(3))(2)](+), [Co(P(2)C(2)R(2))(2)](-), and [Au{Co(P(2)C(2)R(2))(2)}(2)](-) (R = tPent and Ad).

Molecular squares are among the most common supramolecular architectures, but phospha-organometallic complexes have not been used as building blocks for this type of structure. Herein we describe the formation of the molecular square [Au{Co(P2C2tBu2)2}]4 (1) by the self-assembly of anionic 1,3-diphosphacyclobutadiene cobalt complexes and gold(I) cations. The X-ray crystallographic determination of the molecular structure of 1 is complemented by solid-state (31)P and (13)C NMR investigations. High-level DFT calculations confirm the assignment of the (31)P and (13)C NMR resonances.

A practical cobalt-catalyzed hetero-biaryl coupling reaction between aryl chlorides and arylmagnesium halides with unprecedented selectivity has been developed. The protocol utilizes 1 mol% of cheap Co(acac) 3 as pre-catalyst and effects clean reactions of deactivated chlorostyrenes with only 1.1 equiv. of the Grignard reagent under mild conditions (30 C, 5-30 min). Highly chemoselective reactions were realized even in the presence of activated bromoarenes. The olefin substituent facilitates the activation of the C-Cl bond by coordination to the catalyst. Kinetic studies indicate the operation of an arylcobaltate(I) catalyst species. Catalyst formation during the induction period was studied in the presence of cobalt(III), (I), and (ÀI) pre-catalysts. Results and discussion Discovery of a cobalt-catalyzed cross-couplingBuilding on earlier work with iron catalysts, 5 we studied the reaction of 2-chlorostyrene (1) with p-anisylmagnesium bromide

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The dissymmetrical naphthalene-bridged complexes [Cp′Fe(μ-C 10 H 8 )FeCp*] (3; Cp* = η 5 -C 5 Me 5 , Cp′ = η 5 -C 5 H 2 -1,2,4-tBu 3 ) and [Cp′Fe(μ-C 10 H 8 )RuCp*] (4) were synthesized via a one-pot procedure from FeCl 2 (thf) 1.5 , Cp′K, KC 10 H 8 , and [Cp*FeCl(tmeda)] (tmeda = N,N,N′,N′tetramethylethylenediamine) or [Cp*RuCl] 4 , respectively. The symmetrically substituted iron ruthenium complex [Cp*Fe(μ-C 10 H 8 )RuCp*] (5) bearing two Cp* ligands was prepared as a reference compound. Compounds 3−5 are diamagnetic and display similar molecular structures, where the metal atoms are coordinated to opposite sides of the bridging naphthalene molecule. Cyclic voltammetry and UV/vis spectroelectrochemistry studies revealed that neutral 3−5 can be oxidized to monocations 3 + −5 + and dications 3 2+ −5 2+ . The chemical oxidation of 3 and 4 with [Cp 2 Fe]PF 6 afforded the paramagnetic hexafluorophosphate salts [Cp′Fe(μ-C 10 H 8 )FeCp*]PF 6 ([3]PF 6 ) and [Cp′Fe(μ-C 10 H 8 )RuCp*]PF 6 ([4]PF 6 ), which were characterized by various spectroscopic techniques, including EPR and 57 Fe Mossbauer spectroscopy. The molecular structure of [4]PF 6 was determined by X-ray crystallography. DFT calculations support the structural and spectroscopic data and determine the compositions of frontier molecular orbitals in the investigated complexes. The effects of substituting Cp* with Cp′ and Fe with Ru on the electronic structures and the structural and spectroscopic properties are analyzed.

We report the synthesis of functionalized 1,3-bis(diphosphacyclobutadiene) complexes via the insertion of carbon-oxygen bonds of ethers, esters, aldehydes and amides into the P–Si bond of silylated complexes. Reactions of [K(tol)2][Co(η4-P2C2R2)2] [[K(tol)2][1a]: R=tBu, [K(tol)2][1b]: R=tPent (=tert-pentyl)] with Me3SiCl afford the trimethylsilyl-substituted derivatives [Co(η4-P2C2R2SiMe3)(η4-P2C2R2)] (2a,b, R=tBu, tPent). The Me3Si group is connected to a phosphorus atom of one of the 1,3-diphosphacyclobutadiene ligands. 2a,b readily react with organic substrates containing C–O single and C=O double bonds at ambient temperature. [Co(η4-P2C2R2(CH2)4OSiMe3)(η4-P2C2R2)] (3a, b) are formed by reaction of 2a, b with traces of THF. They can also be isolated by reacting the THF solvates [K(thf)2{Co(P2C2tBu2)2}] ([K(thf)2][1a]) and [K(thf)3{Co(P2C2tPent2)2}] ([K(thf)3][1b]) with Me3SiCl in toluene or THF. The adamantyl-substituted complex [Co(η4-P2C2Ad2(CH2)4OSiMe3)(η4-P2C2Ad2)] (3c) was prepared analogously from [K(thf)4{Co(P2C2Ad2)2}] and Me3SiCl. [K(thf)2][1a] reacts cleanly with Ph3SnCl affording [Co(η4-P2C2tBu2SnPh3)(η4-P2C2tBu2)] (4) in high yield. Reaction of 2a with styrene oxide affords [Co(η4-P2C2tBu2PhC2H3OSiMe3)(η4-P2C2tBu2)] (5) as a single regioisomer. By contrast, multinuclear NMR spectroscopic studies indicate mixtures of two isomeric insertion products 6/6′ and 7/7′, respectively, which result from the insertion of 1,2-epoxy-2-methylpropane and 1,2-epoxyoctane. Moreover, these monitoring studies show that reactions of 2a with acyclic ethers afford alkyl substituted complexes such as [Co(η4-P2C2tBu2Et)(η4-P2C2tBu2)] (8) and alkylsilyl ethers. Reaction of 2a with γ-butyrolactone gives [Co(η4-P2C2tBu2(CH2)3C(O)OSiMe3)(η4-P2C2tBu2)] (9) via cleavage of the endocyclic C–O single bond of the lactone. Benzaldehyde and acetone cleanly react with 2a to [Co(η4-P2C2tBu2CH(Ph)OSiMe3)(η4-P2C2tBu2)] (10) and [Co(η4-P2C2tBu2CMe2OSiMe3)(η4-P2C2tBu2)] (11), while the sterically more demanding ketones 3-pentanone and acetophenone selectively yield the known hydride complex [Co(η4-P2C2tBu2)2H] (A). Phenyl isocyanate reacts with 2a at elevated temperature to form [Co(η3-P2C2tBu2CON(Ph)SiMe3)(η4-P2C2tBu2)] (12) with a functionalized η3-coordinated ligand. [K(tol)2][1a], [K(tol)2][1b], 2a, 2b, 3a–c, 4, 5, and 9–12 were isolated and characterized by multinuclear NMR spectroscopy, UV/Vis spectroscopy and elemental analysis. [K(tol)2][1b], 2a, 2b, 3c, 4, 5, and 9–12 were additionally characterized by X-ray crystallography.

Keywords: Copper / Silver / Cobalt / Phosphorus / Sandwich complexes 1,3-Diphosphacyclobutadiene complexes have previously been employed as metalloligands to a few transition metals such as tungsten, cobalt, rhodium, platinum, and gold. Here, we describe the synthesis and the structural and spectroscopic characterization of novel copper(I) and silver(I) complexes with the sandwich anions [Co(η 4 -P 2 C 2 R 2 ) 2 ] -(R = tBu or tPent). Reactions of [K(thf) 3 {Co(P 2 C 2 tPent 2 ) 2 }] and [K(thf) 2 -{Co(P 2 C 2 tBu 2 ) 2 }] with CuCl(PPh 3 )/PPh 3 yielded mononuclear copper(I) complexes [Cu{Co(P 2 C 2 R 2 ) 2 }(PPh 3 ) 2 ] [R = tPent (1), tBu (2)]. The salt [Cu(PMe 3 ) 4 ][Co(P 2 C 2 tPent 2 ) 2 ] (3), which consists of a [Cu(PMe 3 ) 4 ] + cation and a noncoordinated [Co(P 2 C 2 tPent 2 ) 2 ]anion, was obtained when [K(thf) 3 -{Co(P 2 C 2 tPent 2 ) 2 }] was treated with CuCl(PPh 3 ) in the presence of an excess amount of PMe 3 . Salt metathesis of [K(thf) 3 -{Co(P 2 C 2 tPent 2 ) 2 }] with AgCl and AgSbF 6 in the presence of [a]

Molekulare Quadrate gehçren zu den bekanntesten Typen von supramolekularen Architekturen. Phosphorhaltige metallorganische Baueinheiten fanden in derartigen Strukturen bisher allerdings keine Verwendung. Hier beschreiben wir die Synthese eines molekularen Quadrats aus vier Gold-und vier Cobaltatomen, das durch Selbstorganisation von anionischen 1,3-Diphosphacyclobutadien-Komplexen und Gold