Dinuclear niobium(III) and tantalum(III) complexes with thioether and selenoether ligands [{MIIIX2(L)}2(μ-X) 2(μ-L)] (M = Nb, Ta; X = Cl, Br; L = R2S, R 2Se): Syntheses, structures, and the optimal conditions and the mechanism of the catalysis for regioselective cyclotrimerization of alkynes

Masatoshi Matsuura, Takashi Fujihara, Masaki Kakeya, Tomoaki Sugaya, Akira Nagasawa

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

A series of dinuclear niobium(III) and tantalum(III) halide complexes with chalcogen donors [{MIIIX2(L)}2(μ-X) 2(μ-L)] (M = Nb; X = Cl, Br; L = R2S, R2Se) (M = Ta; X = Cl, Br; L = R2S) have been prepared by the reaction of dimetal(V) decahalide (M2X10) with magnesium and L. The structures of five of those new complexes were determined by X-ray crystallography to have a M-M double bond. It is evidenced that the solvent and the temperature play important roles in achieving high yield and regioselectivity for cyclotrimerization of alkynes. The reaction of the niobium(III) chloride complexes (L = dimethyl sulfide (Me2S), tetrahydrothiophene (C4H8S, THT, thiolane)) with phenylacetylene at room temperature in toluene gave both head-to-tail cycloadded trimers of alkyne, 1,3,5-(Ph)3-2,4,6-(H)3-benzene and head-to-head cycloadded 1,2,4-(Ph)3-3,5,6-(H)3-benzene, in high yields. The smaller the thioether ligands, the higher the catalytic activity. The niobium(III) chloride complexes with selenoether (L = dimethyl selenide (Me2Se), tetrahydroselenophene (C4H 8Se, THSe, selenolane) have higher rates for the reaction with alkynes, but low activity for the cyclotrimerization. Tantalum(III) chloride complexes (L = Me2S, THT, tetrahydrothiopyran (C5H 10S, THTP, thiane)) have lower catalytic activities than the niobium(III) ones, because the Ta-S(μ-L) bond lengths are shorter than those of niobium analogs. The stability of the precursor complexes toward the first oxidative addition depends on the M-S(μ-L) bond strength, and controls the concentration of catalytic active species. The niobium(III) bromide complexes (L = Me2S, THT) and the tantalum(III) bromide one (L = Me2S) react with alkynes to give head-to-tail compounds regioselectively, but are less catalytically active than those of chloride complexes.

Original languageEnglish
Pages (from-to)288-298
Number of pages11
JournalJournal of Organometallic Chemistry
Volume745-746
DOIs
Publication statusPublished - 2013
Externally publishedYes

Fingerprint

Niobium
Tantalum
Alkynes
Sulfides
alkynes
tantalum
Catalysis
niobium
catalysis
Ligands
ligands
Chlorides
synthesis
chlorides
Benzene
Bromides
catalytic activity
bromides
Catalyst activity
Chalcogens

Keywords

  • Alkyne
  • Chalcogen
  • Cyclotrimerization
  • Niobium
  • Regioselectivity
  • Tantalum

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Organic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Biochemistry

Cite this

@article{e59605e0a00f4c53b7580d75b8a8bb33,
title = "Dinuclear niobium(III) and tantalum(III) complexes with thioether and selenoether ligands [{MIIIX2(L)}2(μ-X) 2(μ-L)] (M = Nb, Ta; X = Cl, Br; L = R2S, R 2Se): Syntheses, structures, and the optimal conditions and the mechanism of the catalysis for regioselective cyclotrimerization of alkynes",
abstract = "A series of dinuclear niobium(III) and tantalum(III) halide complexes with chalcogen donors [{MIIIX2(L)}2(μ-X) 2(μ-L)] (M = Nb; X = Cl, Br; L = R2S, R2Se) (M = Ta; X = Cl, Br; L = R2S) have been prepared by the reaction of dimetal(V) decahalide (M2X10) with magnesium and L. The structures of five of those new complexes were determined by X-ray crystallography to have a M-M double bond. It is evidenced that the solvent and the temperature play important roles in achieving high yield and regioselectivity for cyclotrimerization of alkynes. The reaction of the niobium(III) chloride complexes (L = dimethyl sulfide (Me2S), tetrahydrothiophene (C4H8S, THT, thiolane)) with phenylacetylene at room temperature in toluene gave both head-to-tail cycloadded trimers of alkyne, 1,3,5-(Ph)3-2,4,6-(H)3-benzene and head-to-head cycloadded 1,2,4-(Ph)3-3,5,6-(H)3-benzene, in high yields. The smaller the thioether ligands, the higher the catalytic activity. The niobium(III) chloride complexes with selenoether (L = dimethyl selenide (Me2Se), tetrahydroselenophene (C4H 8Se, THSe, selenolane) have higher rates for the reaction with alkynes, but low activity for the cyclotrimerization. Tantalum(III) chloride complexes (L = Me2S, THT, tetrahydrothiopyran (C5H 10S, THTP, thiane)) have lower catalytic activities than the niobium(III) ones, because the Ta-S(μ-L) bond lengths are shorter than those of niobium analogs. The stability of the precursor complexes toward the first oxidative addition depends on the M-S(μ-L) bond strength, and controls the concentration of catalytic active species. The niobium(III) bromide complexes (L = Me2S, THT) and the tantalum(III) bromide one (L = Me2S) react with alkynes to give head-to-tail compounds regioselectively, but are less catalytically active than those of chloride complexes.",
keywords = "Alkyne, Chalcogen, Cyclotrimerization, Niobium, Regioselectivity, Tantalum",
author = "Masatoshi Matsuura and Takashi Fujihara and Masaki Kakeya and Tomoaki Sugaya and Akira Nagasawa",
year = "2013",
doi = "10.1016/j.jorganchem.2013.07.035",
language = "English",
volume = "745-746",
pages = "288--298",
journal = "Journal of Organometallic Chemistry",
issn = "0022-328X",
publisher = "Elsevier",

}

TY - JOUR

T1 - Dinuclear niobium(III) and tantalum(III) complexes with thioether and selenoether ligands [{MIIIX2(L)}2(μ-X) 2(μ-L)] (M = Nb, Ta; X = Cl, Br; L = R2S, R 2Se)

T2 - Syntheses, structures, and the optimal conditions and the mechanism of the catalysis for regioselective cyclotrimerization of alkynes

AU - Matsuura, Masatoshi

AU - Fujihara, Takashi

AU - Kakeya, Masaki

AU - Sugaya, Tomoaki

AU - Nagasawa, Akira

PY - 2013

Y1 - 2013

N2 - A series of dinuclear niobium(III) and tantalum(III) halide complexes with chalcogen donors [{MIIIX2(L)}2(μ-X) 2(μ-L)] (M = Nb; X = Cl, Br; L = R2S, R2Se) (M = Ta; X = Cl, Br; L = R2S) have been prepared by the reaction of dimetal(V) decahalide (M2X10) with magnesium and L. The structures of five of those new complexes were determined by X-ray crystallography to have a M-M double bond. It is evidenced that the solvent and the temperature play important roles in achieving high yield and regioselectivity for cyclotrimerization of alkynes. The reaction of the niobium(III) chloride complexes (L = dimethyl sulfide (Me2S), tetrahydrothiophene (C4H8S, THT, thiolane)) with phenylacetylene at room temperature in toluene gave both head-to-tail cycloadded trimers of alkyne, 1,3,5-(Ph)3-2,4,6-(H)3-benzene and head-to-head cycloadded 1,2,4-(Ph)3-3,5,6-(H)3-benzene, in high yields. The smaller the thioether ligands, the higher the catalytic activity. The niobium(III) chloride complexes with selenoether (L = dimethyl selenide (Me2Se), tetrahydroselenophene (C4H 8Se, THSe, selenolane) have higher rates for the reaction with alkynes, but low activity for the cyclotrimerization. Tantalum(III) chloride complexes (L = Me2S, THT, tetrahydrothiopyran (C5H 10S, THTP, thiane)) have lower catalytic activities than the niobium(III) ones, because the Ta-S(μ-L) bond lengths are shorter than those of niobium analogs. The stability of the precursor complexes toward the first oxidative addition depends on the M-S(μ-L) bond strength, and controls the concentration of catalytic active species. The niobium(III) bromide complexes (L = Me2S, THT) and the tantalum(III) bromide one (L = Me2S) react with alkynes to give head-to-tail compounds regioselectively, but are less catalytically active than those of chloride complexes.

AB - A series of dinuclear niobium(III) and tantalum(III) halide complexes with chalcogen donors [{MIIIX2(L)}2(μ-X) 2(μ-L)] (M = Nb; X = Cl, Br; L = R2S, R2Se) (M = Ta; X = Cl, Br; L = R2S) have been prepared by the reaction of dimetal(V) decahalide (M2X10) with magnesium and L. The structures of five of those new complexes were determined by X-ray crystallography to have a M-M double bond. It is evidenced that the solvent and the temperature play important roles in achieving high yield and regioselectivity for cyclotrimerization of alkynes. The reaction of the niobium(III) chloride complexes (L = dimethyl sulfide (Me2S), tetrahydrothiophene (C4H8S, THT, thiolane)) with phenylacetylene at room temperature in toluene gave both head-to-tail cycloadded trimers of alkyne, 1,3,5-(Ph)3-2,4,6-(H)3-benzene and head-to-head cycloadded 1,2,4-(Ph)3-3,5,6-(H)3-benzene, in high yields. The smaller the thioether ligands, the higher the catalytic activity. The niobium(III) chloride complexes with selenoether (L = dimethyl selenide (Me2Se), tetrahydroselenophene (C4H 8Se, THSe, selenolane) have higher rates for the reaction with alkynes, but low activity for the cyclotrimerization. Tantalum(III) chloride complexes (L = Me2S, THT, tetrahydrothiopyran (C5H 10S, THTP, thiane)) have lower catalytic activities than the niobium(III) ones, because the Ta-S(μ-L) bond lengths are shorter than those of niobium analogs. The stability of the precursor complexes toward the first oxidative addition depends on the M-S(μ-L) bond strength, and controls the concentration of catalytic active species. The niobium(III) bromide complexes (L = Me2S, THT) and the tantalum(III) bromide one (L = Me2S) react with alkynes to give head-to-tail compounds regioselectively, but are less catalytically active than those of chloride complexes.

KW - Alkyne

KW - Chalcogen

KW - Cyclotrimerization

KW - Niobium

KW - Regioselectivity

KW - Tantalum

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U2 - 10.1016/j.jorganchem.2013.07.035

DO - 10.1016/j.jorganchem.2013.07.035

M3 - Article

AN - SCOPUS:84883174991

VL - 745-746

SP - 288

EP - 298

JO - Journal of Organometallic Chemistry

JF - Journal of Organometallic Chemistry

SN - 0022-328X

ER -