Binuclear Vanadium Complex Research Articles

Synthesis, characterization and ethylene (Co)polymerization of binuclear Vanadium(IV) catalysts based on xanthene-bridged bis-salicylaldiminato ligands

Bimetallic complexes have attracted much attention due to their excellent catalytic performances in many fields. Herein six xanthene-bridged bis-salicylaldiminato [ON] bidentate binuclear vanadium(IV) complexes V2L1-V2L6 were synthesized and characterized by MALDI-TOF-MS, FTIR spectroscopy and elemental analysis, and the crystal structures of V2L1 and V2L2 were further characterized by XRD, in which each vanadium atom was found coordinated with three O, one Cl and one N atoms to form a twisted trigonal bipyramidal configuration. Under Et2AlCl and ethyl trichloroacetate (ETA) activation, all the binuclear vanadium(IV) complexes exhibited high activity over 106 g/mol(V)·h·atm towards ethylene polymerization and copolymerization with 1-hexene. The activity of binuclear V2L4 for ethylene polymerization was much higher than that of its mononuclear counterpart VL, indicating that strong bimetallic synergetic effect existed in these binuclear vanadium complexes. The substituents on the ligands have a great influence on the catalytic performances of the vanadium complexes. The introduction of bulky isopropyl group into the ligand had little effect on the activity, but the introduction of electron-withdrawing fluorine atoms could significantly increase the activity, suggesting that the electronic, rather than the steric factors had a greater impact. As the amount of fluorine substituent on the iminophenyl moiety of the complex increased, the catalytic activity increased appreciably. With five fluorine atoms on the benzene ring of the imine moiety, the complex V2L6 showed the highest activity of 1.10 × 107 g/mol(V)·h·atm for ethylene polymerization to produce the highest molecular weight of polyethylene. Furthermore, the introduction of fluorine atoms into ligands could also increase the catalytic activity of vanadium complexes, comonomer incorporation and molecular weight of obtained copolymer towards ethylene/1-hexene copolymerization. The highest copolymerization activity of V2L6 was 4.13 × 106 g/molV·h·atm, which was more than three time that of the fluorine-free complex V2L1. The insertion rate of 1-hexene for the fluorine-containing complex V2L3-V2L6 was also higher than that for V2L1.

Design and synthesis of binuclear vanadium catalysts for copolymerization of ethylene and polar monomers

Binuclear vanadium complexes exhibited higher activity than monometallic complexes in ethylene polymerization and afforded UHMWPE. The binuclear catalysts also showed moderate activity in copolymerization with 10-undecen-1-ol and methyl 10-undecenoate.

Inside Cover Picture

The cover picture shows binuclear vanadium complexes for ROMP, which revealed unexpected backbiting reaction between two in‐situ formed alkylidenes. The following REMP gives the formation of polymer with cyclic topology. More details are discussed in the article by Wu et al. on page 1181—1187.image

Hydrogen-Bond Influenced Synthesis and Crystal Structures of (4-Chloro-2-[(2-dimethylaminoethylimino)methyl] phenolato)dioxovanadium(V) and Bis(2-[(2-aminoethylimino)methyl]-4-bromophenolato) dioxovanadium(V)

A mononuclear vanadium complex, [VO2La] (1) (La = 4-chloro- 2-[(2-dimethylaminoethylimino)methyl]phenolate), and a binuclear vanadium complex, [VO2Lb]2 (2) (Lb = 2-[(2-aminoethyl imino)methyl]-4-bromophenolate), were prepared and characterized by physical chemical methods (IR and UV-Vis spectra, elemental analysis), and single crystal X-ray diffraction. The V coordinate center in (1) is ligated by three NNO donor atoms of the Schiff base ligand La, and two oxo groups, generating pyramidal coordination. Each V coordinate center in (2) is ligated by three NNO donor atoms of the Schiff base ligand Lb, and three oxo groups, generating octahedral coordination. Close examination on the relationship between structures of Schiff base ligands and the final complexes, hydrogen bonds are the substantial influence factors in the self-assembly processes.

A binuclear oxovanadium(V) complex containing a tetrasulphido bridging ligand: synthesis, characterization, mechanism, TG-DTA analysis and UV–Vis spectra

A binuclear vanadium(V) complex {[VO(OCH3)C9H7ON3S2]2} was synthesized by reaction of VCl3 with 2-hydroxyacetophenone thiosemicarbazone (ONS ligand). The tridentate thiosemicarbazone did not utilize the thiolate or thione sulfur for coordination to vanadium, but rather employed the–NH2 moiety; a binuclear vanadium complex containing a tetrasulphido bridging ligand was formed. The title complex is monoclinic, space group P21/n.

Ab Initio Analysis of Exchange Interactions in [V2O(BIPY)4CL2]2+ Complex

In this work an ab initio analysis of the binuclear vanadium complex [V2O(bipy)4Cl2]2+ electronic structure is performed. The ground state was calculated to be a quintet, which means a ferromagnetic interaction between centers. The orbitals participating in exchange interaction according to ROHF+CI calculations are two molecular orbitals consisting of vanadium d-orbitals and two molecular orbitals with main contributions from p-orbitals of bipyridine ligands perpendicular to V-V axis, vanadium d- and p-orbitals and μ-oxygen p-orbital. Calculated energy values of the multielectronic states are placed in accordance with Lande rule. The value of magnetic moment at 293K calculated for the complex in vacuum taking into consideration the Boltzmann distribution and the energies of the excited states is 3.95BM which is in accordance with experimental value of 3.99BM (for complex in acetone).

Synthesis and crystal structures of low-valent binuclear vanadium complexes using the tethering ligand m-xylylenebis(acetylacetonate) (m-xba2−)

An intriguing structural type new to low-valent vanadium chemistry and the binucleating ligand m-H2xba is exhibited by the reported VIII dimers and the first structurally characterized bis(acetylacetonate) ligated complex of VII.

Metal-metal coupling and metal-ligand interactions in four binuclear complexes of vanadium(I), -(II), and -(III). An ab initio CI study

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetal-metal coupling and metal-ligand interactions in four binuclear complexes of vanadium(I), -(II), and -(III). An ab initio CI studyCharles Poumbga, Chantal Daniel, and Marc BenardCite this: J. Am. Chem. Soc. 1991, 113, 4, 1090–1102Publication Date (Print):February 1, 1991Publication History Published online1 May 2002Published inissue 1 February 1991https://doi.org/10.1021/ja00004a006RIGHTS & PERMISSIONSArticle Views124Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts

ChemInform Abstract: Syntheses, Electrochemistry, and Spectroscopic and Magnetic Properties of New Mononuclear and Binuclear Complexes of Vanadium(III), ‐(IV), and ‐(V) Containing the Tridentate Macrocycle 1,4,7‐Trimethyl‐1,4,7‐triazacyclononane (L). Crystal Structures of (L2V2(acac)2(μ‐O))I2·2 H2O, (L2V2O4(μ‐O))·14 H2O, and (L2V2O2(OH)2(μ‐O))(ClO4)2.

Abstract(I) and (III), containing the blocking macrocyclic ligand and labile ionic ligands, are useful starting materials for a variety of mono‐ and binuclear complexes of vanadium.

Syntheses, electrochemistry, and spectroscopic and magnetic properties of new mononuclear and binuclear complexes of vanadium(III), -(IV, and -(V) containing the tridentate macrocycle 1,4,7-trimethyl-1,4,7-triazacyclononane (L). Crystal structures of [L2V2(acac)2(.mu.-O)]I2.2H2O, [L2V2O4(.mu.-O)].14H2O, and [L2V2O2(OH)2(.mu.-O)](ClO4)2

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSyntheses, electrochemistry, and spectroscopic and magnetic properties of new mononuclear and binuclear complexes of vanadium(III), -(IV, and -(V) containing the tridentate macrocycle 1,4,7-trimethyl-1,4,7-triazacyclononane (L). Crystal structures of [L2V2(acac)2(.mu.-O)]I2.2H2O, [L2V2O4(.mu.-O)].14H2O, and [L2V2O2(OH)2(.mu.-O)](ClO4)2Petra Knopp, Karl Wieghardt, Bernhard Nuber, Johannes Weiss, and William S. SheldrickCite this: Inorg. Chem. 1990, 29, 3, 363–371Publication Date (Print):February 1, 1990Publication History Published online1 May 2002Published inissue 1 February 1990https://doi.org/10.1021/ic00328a004RIGHTS & PERMISSIONSArticle Views464Altmetric-Citations84LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Binuclear vanadium complexes containing sulfur and selenium ligands: The reactions of the half-sandwich compounds CpV(CO) 4 and Cp ★V(CO) 4 with dichalcogenides E 2R 2 (E = S, Se; R = Me, Ph). The X-ray crystallographic structures of Cp ★2V 2(CO) 4(μ-SR) 2 (R = Me, Ph; Cp ★ = C 5Me 5)

Both the photo-induced reaction of CpV(CO) 4 ( 1) and Cp ★V(CO) 4 ( 1 ★) (Cp = C 5H 5, Cp ★ = C 5Me 5) with diorganochalcogenides, E 2R 2 (E = S, Se; R = Me, Ph) at room temperature in THF solution and the thermal reaction of the kinetically labile derivatives CpV(CO) 3(SMe 2) ( 7) and Cp ★V(CO) 3(SMe 2) ( 7 ★) with E 2R 2 in solution lead to binuclear, diamagnetic complexes Cp 2- and Cp 2 ★-V 2(CO) 4(μ-ER) 2 ( 8, R = Me and 9, R = Ph). In the presence of excess E 2R 2, further decarbonylation takes place to give paramagnetic Cp 2- and Cp 2 ★-V 2(μ-ER) 4 ( 10, R = Me and 11, R = Ph). With H 2S, both 1 ★ and 7 ★ can be converted into a labile intermediate Cp ★ 2V 2(CO) 4(μ-S) 2 ( 12 ★) which tends to lose the CO ligands. No carbonyl-containing intermediates were observed in the reactions of 1 ★ and 7 ★ with excess sulfur or selenium to give Cp ★ 2V 2E 5 (E = S ( 2a ★) and Se ( 2b ★)) and Cp ★ 2V 2E 4 (E = S, 3a ★ and Se, 3b ★), respectively. The carbonylvanadium complexes were characterized by their 1H, 13C and 51V NMR spectra. X-Ray crystallographic structure analyses carried out for Cp ★ 2V 2(CO) 4(μ-SMe) 2 ( 8a ★) and Cp ★ 2V 2(CO) 4(μ-SPh) 2 ( 9a ★) revealed a bent V 2(μ-SR) 2 core. The Cp ★ ligands are arranged cis to each other, and the organo substituents occupy the exo/ exo positions. The vanadium-vanadium distance is 3.083(1) Å in 8a ★ and 3.070(1) Å in 9a ★.

CRYSTAL STRUCTURE INVESTIGATION OF VANADYL COMPLEXES OF TRIDENTATE LIGAND (I)——THE CRYSTAL STRUCTURES OF BIS[(1-(2,4-PENTANE- DIONATO(NITROBENZOYL) HYDRAZONE)-2- ETHOXY)OXOVANADIUM] AND BIS-[(1-(2, 4-PENTANEDIONATO-(3-NITROBENZOYL) HYDRAZONE)-2

The title complexes were obtained by the reactions of bis(2,4-pentanedionato)oxovanadium VO(Acac) 2 and m-nitrophenylhydrazide m-NO 2 PhCONHNH 2 in the media EtOH and MeOH respectively. The compound (Ⅰ) crystallizes in the space group PT with unit cell dimensions a =8.123(2), b =10.409(5), c =10.822(4), α =65.78(3)°, β =85.50(3)°, γ =89.04(3)°. The compound (Ⅱ) crystallizes in the space group P2 1 /a with unit cell dimensions a =7.745(2), b =19.164(5), c =10.787(4), β=107.87(2)°. The resuhs of structural analyses show that the two compounds have the same characteristics: the tridentate ligand formed by condensation occupies three of the four equatorial positions of vanadium and the rest equatorial position is occupied by alkoxy group RO - . As RO - group also bridges the sixth coordinated position of each vanadium atom, it brings about the formation of the new type binuclear complexes of vanadium.

Darstellung und Struktur eines zweikernigen Vanadium(V)-Komplexes mit den terminal gebundenen Stickstoffliganden NtC4H9, NHtC4H9 und NH2 tC4H9: [ VCl(μ-Cl)(NtC4H9)(NHtC4H9) (NH2 tC4H9) ]2 / Synthesis and Molecular Structure of a Binuclear Vanadium(V) Complex Containing the Terminal Nitrogen Ligands NtC4H9, NHtC4H9, NH2 tC4H9: [VCl(μ-Cl)(NtC4H9)(NHtC4H9)(NH2 tC4H9)]2

tC4H9N = VCl2(NHtC4H9) and the tert-butylamine complex [tC4H9N=VCl2(NHtC4H9)(NH2 tC4H9)] have been prepared by reaction of tC4H9N=VCl3 with NH2 tC4H9. 1H and 51V NMR data of these compounds are reported. The complex was investigated by X-ray diffraction analysis; the structure has been found to be a binuclear vanadium complex bridged by two Cl-atoms with a distorted octahedral arrangement of the ligands.