The transition-metal chemistry of amidinatosilylenes, -germylenes and -stannylenes

Álvarez-Rodríguez, Lucía; Cabeza, Javier A.; García‐Álvarez, Pablo; Polo, Diego

doi:10.1016/j.ccr.2015.04.008

Cited by 211 publications

(99 citation statements)

References 232 publications

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“…As shown by DFT calculations, in the Zn−Si compounds [PhC(N t Bu) 2 (R)SiZn(R)Cl] reported by us, a strong Zn−Si bond and a weak Zn−Cl bond are formed, suggesting an ion pair consisting of a silyl cation with a Zn−Si single bond rather than a classical donor–acceptor bond of a silylene (Scheme ). A similar polarization may be anticipated in other metal NHSi complexes . This raises the question under which conditions a “true” silylene with a classical donor–acceptor bond is formed.…”

Section: Introductionsupporting

confidence: 66%

Investigations of the Nature of Zn^II−Si^II Bonds

Schäfer

Köppe

Roesky

2016

Chemistry A European J

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A series of zinc(II) silylenes was prepared by using the silylene {PhC(NtBu)2 }(C5 Me5 )Si. Whereas reaction of the silylene with ZnX2 (X=Cl, I) gave the halide-bridged dimers [{PhC(NtBu)2 }(C5 Me5 )SiZnX(μ-X)]2 , with ZnR2 (R=Ph, Et, C6 F5 ) as reagent the monomers [{PhC(NtBu)2 }(C5 Me5 )SiZnR2 ] were obtained. The stability of the complexes and the Zn-Si bond lengths clearly depend on the substitution pattern of the zinc atom. Electron-withdrawing groups stabilize these adducts, whereas electron-donating groups destabilize them. This could be rationalized by quantum chemical calculations. Two different bonding modes in these molecules were identified, which are responsible for the differences in reactivity: 1) strong polar Zn-Si single bonds with short Zn-Si distances, Zn-Si force constants close to that of a classical single bond, and strong binding energy (ca. 2.39 Å, 1.33 mdyn Å(-1) , and 200 kJ mol(-1) ), which suggest an ion pair consisting of a silyl cation with a Zn-Si single bond; 2) relatively weak donor-acceptor Zn-Si bonds with long Zn-Si distances, low Zn-Si force constants, and weak binding energy (ca. 2.49 Å, 0.89 mdyn Å(-1) , and 115 kJ mol(-1) ), which can be interpreted as a silylene-zinc adduct.

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Section: Introductionsupporting

confidence: 66%

Investigations of the Nature of Zn^II−Si^II Bonds

Schäfer

Köppe

Roesky

2016

Chemistry A European J

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“…Within the family of donor‐stabilized silylenes, those having an amidinato fragment are being increasingly used because their syntheses are relatively easy and their electronic and steric properties can be easily tuned . In this context, we have recently achieved the first insertion of a carbene fragment into an N−Si bond by treating an amidinatosilylene with a tungsten Fischer methyl(ethoxy)carbene complex at room temperature (Scheme ) .…”

Section: Methodsmentioning

confidence: 99%

Unexpected Zwitterionic Allenyls from Silylenes and a Fischer Alkynylcarbene: A Remarkable Silylene‐Promoted Rearrangement

Cabeza

García‐Álvarez

Gallego

et al. 2019

Chemistry A European J

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The silylenes Si(tBu2bzam)R (tBu2bzam=N,N′‐bis(tertbutyl)benzamidinate; R=mesityl, CH2SiMe3) attack the Ccarbene atom of the Fischer alkynyl(ethoxy)carbene complex [W(CO)5{C(OEt)C2Ph}] to give, after a striking rearrangement, zwitterionic σ‐allenyl complexes in which the original carbene C atom forms part of the allene C3 fragment and also of a Si‐C‐N‐C‐N five‐membered ring after insertion into a Si−N bond of the original amidinatosilylene. These remarkable allenyl products, which contain two stereogenic groups, are selectively formed as single diastereomers.

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“…[5] Some of the low valent main group metal/oid amidinate complexes are frequently used as ligands for complexation of transition metals. [6] In particular, the biggest attention has been paid to the investigation of various metal complexes containing amidinate or guanidinate ligands, or its variations, as catalysts for various organic chemistry transformations. [7,8,9,10] The application of these complexes as a single source precursors of new materials [11] together with stabilization of unusual [12,13], generally lower, oxidation states of metals in its complexes opened new areas of chemistry [14].…”

Section: Introductionmentioning

confidence: 99%