Preparation and Thermal Reaction of Tetrastannapalladacyclopentane. Sn−Sn Bond Formation and Cleavage

Tanabe, Makoto; Hanzawa, Masaya; Osakada, Kohtaro

doi:10.1021/om100281t

Cited by 15 publications

(5 citation statements)

References 63 publications

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“…While the typical region for the chemical shift of doubly bonded tin atoms is downfield of +400 ppm, the 119 Sn NMR resonances of 3 , 4 , 5 , 6 , and 10 were found to exhibit shifts of δ = −488.0 ppm, −280.3 ppm, −310.2 ppm, −316.3 ppm, and −430.2 ppm, respectively. A comparison with the 119 Sn shift of [(dmpe)Pd(SnPh 3 ) 2 ] 21 of −40.4 ppm suggests metallacycle stannyl–Pt/Pd type bonds with the resonances shifted further upfield because of the silyl substituents and the three-membered ring. In a similar way, also the 29 Si NMR shifts of the metal bound silicon atom can be interpreted.…”

Section: Resultsmentioning

confidence: 99%

Coordination Chemistry of Disilylated Stannylenes with Group 10 d¹⁰Transition Metals: Silastannene vs Stannylene Complexation

et al. 2013

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The coordination behavior of disilylated stannylenes toward zerovalent group 10 transition metal complexes was studied. This was accomplished by reactions of PEt3 adducts of disilylated stannylenes with zerovalent group 10 transition metal complexes. The thus obtained products differed between the first row example nickel and its heavier congeners. While with nickel stannylene complex formation was observed, coordination of the stannylenes to palladium and platinum compounds led to unusual silastannene complexes of these metals. A computational model study indicated that in each case metal stannylene complexes were formed first and that the disilylstannylene/silastannene rearrangement occurs only after complexation to the group 10 metal. The isomerization is a two-step process with relatively small barriers, suggesting a thermodynamic control of product formation. In addition, the results of the computational investigation revealed a subtle balance of steric and electronic effects, which determines the relative stability of the metalastannylene complex relative to its silastannene isomer. In the case of cyclic disilylstannylenes, the Pd(0) and Pt(0) silastannene complexes are found to be more stable, while with acyclic disilylstannylenes the Ni(0) stannylene complex is formed preferentially.

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Section: Resultsmentioning

confidence: 99%

Coordination Chemistry of Disilylated Stannylenes with Group 10 d¹⁰Transition Metals: Silastannene vs Stannylene Complexation

et al. 2013

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“…The reaction product contains only 2, PCy 3 , and [Pd(dmpe) 2 ] n (n = 1, 2), 13 as revealed by 31 P{ 1 H} NMR spectroscopy. Heating a mixture of the isolated 2 and dmpe (1:3) at 80 °C regenerates [{Pd(dmpe)} 2 (μ-Ge 2 Ph 4 )(μ-GePh 2 )], accompanied by the formation of [Pd(dmpe) 2 ] n .…”

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“…The treatment of a dipalladium complex with bridging digermene and germylene ligands, [{Pd(dmpe)} 2 (μ-Ge 2 Ph 4 )(μ-GePh 2 )], with twice the molar amount of [Pd(PCy 3 ) 2 ] and then with equimolar dmpe afforded a tetrapalladium complex with bridging germylene ligands, [Pd{Pd(dmpe)} 3 (μ 3 -GePh 2 ) 3 ] ( 2 ): The reaction product contains only 2 , PCy 3 , and [Pd(dmpe) 2 ] n ( n = 1, 2), as revealed by 31 P{ 1 H} NMR spectroscopy. Heating a mixture of the isolated 2 and dmpe (1:3) at 80 °C regenerates [{Pd(dmpe)} 2 (μ-Ge 2 Ph 4 )(μ-GePh 2 )], accompanied by the formation of [Pd(dmpe) 2 ] n .…”

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Tetrapalladium Complex with Bridging Germylene Ligands. Structural Change of the Planar Pd₄Ge₃ Core

et al. 2011

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A complex with a planar hexagonal Pd(4)Ge(3) core, [Pd{Pd(dmpe)}(3)(μ(3)-GePh(2))(3)], was synthesized and characterized by X-ray and NMR measurements as well as by DFT calculations. 4-tert-Butylbenzenethiol converted the Pd(4) complex into a hexapalladium complex, [{Pd(3)(μ-GePh(2))(2)(μ-H)(μ(3)-GePh(2)(SC(6)H(4)(t)Bu-4))}(2)(μ-dmpe)], composed of two Pd(3)Ge(3) units bridged by a dmpe ligand. The addition of CuI or AgI to the Pd(4) complex yielded [Pd(μ-MI){Pd(dmpe)}(3)(μ(3)-GePh(2))(3) ] (M = Cu, Ag), in which Cu or Ag bridges a Pd-Pd bond of the Pd(4)Ge(3) core. The CuI adducts in solution undergo a pivot motion of the CuI on the surface of the Pd(4)Ge(3) plane on the NMR time scale.

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“…The tetrastannapalladacyclopentane [Pd(SnPh 2 SnPh 2 SnPh 2 SnPh 2 )(dmpe)] ( 57 ) was also prepared by starting from the Pd(0) complex by treatment with H 2 SnPh 2 in 1:4 ratio (eq ). Sn−H bonds are easily activated in comparison to Ge−H or Si−H bonds, leading to the formation of a five-membered ring under mild conditions …”

Section: Persilylated and Pergermylated Metallacyclesmentioning

confidence: 99%

Sila- and Germametallacycles of Late Transition Metals

Tanabe

Osakada

2010

Organometallics

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This article reviews recent advances in late-transition-metal complexes with chelating Si and Ge ligands. Compounds with two Si-H bonds, such as bis(silyl)alkanes, bis(silyl)arenes, and tetramethyldisiloxanes, react with Re, Rh, Ir, Pd, and Pt complexes to form disilametallacycles with five-or six-membered chelate rings. Four-and five-membered disilacycloalkanes and disilanyldiylcarboranes undergo Si-Si bond cleavage promoted by Pd(0) and Pt(0) complexes to produce the corresponding disilametallacycles. High reactivity of the Si-Si bond toward oxidative addition facilitates the above ring enlargement, even for compounds with stable five-membered rings. Platinum complexes with a η 2 -silene ligand react with small molecules having electronegative atoms, such as O 2 and NH 3 , to produce metallacycles formed via addition of the electronegative atom to the Si-Si bond. The above disilametallacycles undergo insertion of alkynes and carbonyl compounds into the M-Si bonds of the disilametallacycles. The persilyl metallacycle [ À Pt(SiPh 2 SiPh 2 SiPh 2 À SiPh 2 )(PPh 3 ) 2 ] is obtained by the double oxidative addition of tetrakis-(diphenylsilane) with two Si-H groups and via a metathesis reaction of its dilithio derivative with [PtCl 2 (PPh 3 ) 2 ]. Reactions of H 2 GeAr 2 with Pd(II) and Pt(II) complexes having diphenylgermyl ligands yield the tetragerampalladacyclopentane and its Pt analogue. Trigermaplatinacyclobutane reacts with Ph 2 GeH 2 to produce the tetragermaplatinacyclopentane via formal insertion of GePh 2 into a Pt-Ge bond. C versus Si or Ge MetallacyclesThe chemistry of metallacycles 1 has been a major area of organometallic chemistry because of their role as key intermediates in the metathesis 2 and oligomerization 3 of alkenes catalyzed by transition-metal complexes. Five-and six-membered metallacycles are common, and they are stabilized kinetically in many cases. Their M-C bonds undergo various reactions such as insertion of small molecules, reductive elimination of cycloalkanes, and β-hydrogen elimination, but the reactions occur more slowly than for the usual alkyl complexes due to ring strain of the intermediates or the products. Metallacyclobutanes of Mo, W, and Ru with a four-membered-ring structure are known as the actual intermediates of olefin metathesis catalyzed by the transition-metal complexes. 4 Silyl and germyl complexes of late transition metals exhibit different reactivity from the alkyl metal complexes. For example, they prefer R-hydrogen elimination rather than β-hydrogen elimination, which is common as a decomposition pathway of the alkyl complexes. Chemical properties of the metallacycles, having Si or Ge as the coordinating atoms, are expected to be unique, being cyclic versions of the silyl and germyl complexes. Many research groups have investigated the preparation, structures, and chemical properties of such sila-or germametallacycles. Pd and Pt, in particular, are employed as the major elements among late transition metals, probably because the σ-bonds between Si or Ge and thes...

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Preparation and Thermal Reaction of Tetrastannapalladacyclopentane. Sn−Sn Bond Formation and Cleavage

Cited by 15 publications

References 63 publications

Coordination Chemistry of Disilylated Stannylenes with Group 10 d¹⁰Transition Metals: Silastannene vs Stannylene Complexation

Coordination Chemistry of Disilylated Stannylenes with Group 10 d¹⁰Transition Metals: Silastannene vs Stannylene Complexation

Tetrapalladium Complex with Bridging Germylene Ligands. Structural Change of the Planar Pd₄Ge₃ Core

Sila- and Germametallacycles of Late Transition Metals

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Preparation and Thermal Reaction of Tetrastannapalladacyclopentane. Sn−Sn Bond Formation and Cleavage

Cited by 15 publications

References 63 publications

Coordination Chemistry of Disilylated Stannylenes with Group 10 d10Transition Metals: Silastannene vs Stannylene Complexation

Coordination Chemistry of Disilylated Stannylenes with Group 10 d10Transition Metals: Silastannene vs Stannylene Complexation

Tetrapalladium Complex with Bridging Germylene Ligands. Structural Change of the Planar Pd4Ge3 Core

Sila- and Germametallacycles of Late Transition Metals

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Coordination Chemistry of Disilylated Stannylenes with Group 10 d¹⁰Transition Metals: Silastannene vs Stannylene Complexation

Coordination Chemistry of Disilylated Stannylenes with Group 10 d¹⁰Transition Metals: Silastannene vs Stannylene Complexation

Tetrapalladium Complex with Bridging Germylene Ligands. Structural Change of the Planar Pd₄Ge₃ Core