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1.
Chemistry ; 19(51): 17608-12, 2013 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-24218369

RESUMO

Mono- and dinuclear hydridoborylene complexes were prepared by intermetallic borylene transfer from Group VI borylene or metalloborylene reagents. The hydride and borylene ligands were found to interact with each other significantly, although the boron ligand retains much of its former borylene character. Zero-valent platinum fragments were successively added to the dinuclear hydridoborylene complexes, resulting in tri- and tetranuclear borido complexes, in which the B-H interaction has been lost, and the hydride ligands now bridge two metal centers. The complexes were studied spectroscopically, crystallographically, and by DFT methods, and the unusual bonding situation in the M-B-H triangles of hydridoborylene complexes were evaluated.

2.
Chemistry ; 19(40): 13402-7, 2013 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-23959699

RESUMO

The synthesis of base-stabilized boryl and borylene complexes is reported. An N-heterocyclic carbene (NHC)-stabilized iron-dihydroboryl complex was prepared by two different routes including methane liberation and salt elimination. A range of base-stabilized iron-dichloroboryl complexes was prepared by addition of Lewis bases to boryl complexes. Base-stabilized, cationic monochloroborylene complexes were synthesized from these boryl complexes by halide abstraction by using weakly coordinating anions.

4.
Chemistry ; 18(8): 2327-34, 2012 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-22267281

RESUMO

Upon treating transition-metal-dihaloboryl complexes of the form [L(n)MBX(2)] with K[(η(5)-C(5)H(5))MnH(CO)(2)], salt elimination occurs along with a migration of the Mn-bound hydride ligand onto the boron atom, thereby forming dinuclear σ-(halo)boranyl complexes of the form [L(n)M(µ-BHX)Mn(CO)(2)(η(5)-C(5)H(5))]. Most of these complexes react further at room temperature to lose HX and provide metalloborylene complexes [L(n)M-B = Mn(CO)(2)(η(5)-C(5)H(5))]; however, when ML(n) = Re(CO)(5) the σ-(halo)boranyl complex decomposes into unidentifiable products. We found through DFT calculations that two electronically and structurally distinct forms of the intermediate σ-(halo)boranyl complexes exist, one of which easily loses HX and one that does not.

7.
Chem Commun (Camb) ; 47(35): 9900-2, 2011 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-21808766

RESUMO

Intermetallic borylene transfer has been applied to synthesise new borido complexes. Starting from [{(η(5)-C(5)Me(5))Fe(CO)(2))}(µ-B){Cr(CO)(5)}] (1) the borylene moiety has been transferred successfully to different transition metal fragments. In the manner described, two new compounds have been fully characterised in solution and by X-ray crystallography.

8.
Chemistry ; 17(37): 10379-87, 2011 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-21812040

RESUMO

An improved protocol for the selective dilithiation of [V(η(5)-C(5)H(5))(η(7)-C(7)H(7))] has been developed, which afforded [V(η(5)-C(5)H(4)Li)(η(7)-C(7)H(6)Li)]·PMDTA (5; PMDTA=N,N,N',N'',N''-pentamethyldiethylenetriamine) in almost quantitative yield (98%). In the solid state, the species features a dimeric structure with two terminal and two bridging lithium atoms, with the latter connecting both sandwich subunits. Reaction with suitable Group 4 dihalide compounds enabled the isolation of highly strained silicon- and germanium-bridged [1]trovacenophanes 6 and 7. Similarly, reaction of 5 with Cl(2)Sn(2)tBu(4) afforded the rather unstrained complex [V(η(5)-C(5)H(4))(η(7)-C(7)H(6))Sn(2)tBu(4)] (8), which together with 7 represent the first trovacenophanes to incorporate heavier analogues of silicon in the ansa-bridge. Ring-opening polymerization reactions of [V(η(5)-C(5)H(4))(η(7)-C(7)H(6))SiRR'] (2a: R=R'=Me; 6: R=Me, R'=iPr) were performed by heating in a solution of toluene in the presence of the Karstedt catalyst, which resulted in the formation of the corresponding soluble poly(trovacenylsilanes) in yields of 41 and 33%, respectively. As estimated by gel permeation chromatography (GPC), the macromolecules possess molecular weights of M(n)=10,010 and 5580 g mol(-1) with polydispersity indices of 2.31 and 1.64 for 9 and 10, respectively. ESR spectroscopic studies on 9 and 10 revealed only a single broad resonance in each case without any identifiable (51)V hyperfine coupling.

10.
Chemistry ; 16(39): 11985-92, 2010 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-20836094

RESUMO

Syntheses of the first heteroleptic N-heterocyclic carbene (NHC)-phosphane platinum(0) complexes and formation of the corresponding Lewis acid-base adducts with aluminum chloride is reported. The influence of N-heterocyclic carbenes on tuning the Lewis basic properties of the metal complexes was judged from spectroscopic, structural, and computational data. Conclusive experimental evidence for the enhanced Lewis basicity of NHC-containing complexes was provided by a transfer reaction.

11.
Chemistry ; 16(38): 11732-43, 2010 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-20803585

RESUMO

A novel one-pot method was developed for the preparation of [Ti(η(5)-C(5)H(5))(η(7)-C(7)H(7))] (troticene, 1) by reaction of sodium cyclopentadienide (NaCp) with [TiCl(4)(thf)(2)], followed by reduction of the intermediate [(η(5)-C(5)H(5))(2)TiCl(2)] with magnesium in the presence of cycloheptatriene (C(7)H(8)). The [n]troticenophanes 3 (n=1), 4, 8, 10 (n=2), and 11 (n=3) were synthesized by salt elimination reactions between dilithiated troticene, [Ti(η(5)-C(5)H(4)Li)(η(7)-C(7)H(6)Li)]⋅pmdta (2) (pmdta = N,N',N',N'',N''-pentamethyldiethylenetriamine), and the appropriate organoelement dichlorides Cl(2)Sn(Mes)(2) (Mes = 2,4,6-trimethylphenyl), Cl(2)Sn(2)(tBu)(4), Cl(2)B(2)(NMe(2))(2), Cl(2)Si(2)Me(4), and (ClSiMe(2))(2)CH(2), respectively. Their structural characterization was carried out by single-crystal X-ray diffraction and multinuclear NMR spectroscopy. The stanna[1]- and stanna[2]troticenophanes 3 and 4 represent the first heteroleptic sandwich complexes bearing Sn atoms in the ansa bridge. The reaction of 3 with [Pt(PEt(3))(3)] resulted in regioselective insertion of the [Pt(PEt(3))(2)] fragment into the Sn-C(ipso) bond between the tin atom and the seven-membered ring, which afforded the platinastanna[2]troticenophane 5. Oxidative addition was also observed upon treatment of 4 with elemental sulfur or selenium, to produce the [3]troticenophanes [Ti(η(5)-C(5)H(4)SntBu(2))(η(7)-C(7)H(6)SntBu(2))E] (6: E=S; 7: E=Se). The B-B bond of the bora[2]troticenophane 8 was readily cleaved by reaction with [Pt(PEt(3))(3)] to form the corresponding oxidative addition product [Ti(η(5)-C(5)H(4)BNMe(2))(η(7)-C(7)H(6)BNMe(2))Pt(PEt(3))(2)] (9). The solid-state structures of compounds 5, 6, and 9 were also determined by single-crystal X-ray diffraction.

13.
Chem Commun (Camb) ; 46(42): 7894-6, 2010 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-20589310

RESUMO

The synthesis and full characterisation of trans-[PtCl(PCy(3))(2){BiCl(2)}] is reported via the oxidative addition of the bismuth-chloride bond across [Pt(PCy(3))(2)]; this represents the first instance of such an oxidative addition reaction to be undertaken by a bismuth halide bond.

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