5-Methylquinoxaline as a versatile mono-, bi- and tridentate ligand in palladium(II) chemistry. Crystal structures of [Pd(OAc)(C, N4-CH2C8H5N2-5) (PPh 3)]

José Vicente; M. Cristina Lagunas; Elke Bleuel; M. Carmen Ramírez De Arellano

doi:10.1016/S0022-328X(01)01394-8

5-Methylquinoxaline as a versatile mono-, bi- and tridentate ligand in palladium(II) chemistry. Crystal structures of [Pd(OAc)(C, N4-CH₂C₈H₅N₂-5) (PPh ₃)]

José Vicente, M. Cristina Lagunas, Elke Bleuel, M. Carmen Ramírez De Arellano

Queen's University Belfast

Research output: Contribution to journal › Article › peer-review

18 Citations (Scopus)

Abstract

To study the potential coordination versatility of 5-methylquinoxaline, the preparation of complexes which contain it as a mono-, bi- or tridentate ligand was carried out. On reaction with [Pd(OAc)₂] ₃ it coordinates to the metal through its less sterically blocked nitrogen atom (N(1), distal to the Me group) to give trans-[Pd(OAc)₂(N1-C₈H₅N₂ Me-5)₂] (1). Reflux of 1, or a mixture of [Pd(OAc)₂]₃ and 5-methylquinoxaline, in glacial acetic acid gave the cyclometallated acetate-bridged dimer [Pd(C, N4-CH₂C₈H₅N₂-5) (μ-OAc)]₂ (2). Complex 2 reacted with: (i) LiCl to give [Pd(C, N4-CH₂C₈H₅N₂-5) (μ-Cl)]₂ (3); (ii) PPh₃ to give [Pd(C, N4-CH₂C₈H₅N₂-5) (OAc)(PPh₃)] (4); (iii) PR₃ and LiCl to give [Pd(C, N4-CH₂C₈H₅N₂-5)Cl (PR₃)][R = Ph (5), Me (6), Et (7)]; (iv) Tl(acac) to give [Pd(C, N4-CH₂C₈H₅N ₂-5)(O, O-acac)] (8); and (v) 2,2′-bipyridine (bpy)-NaClO₄H₂O to give [Pd(C, N4-CH ₂C₈H₅N₂-5) (bpy)]ClO ₄ (9). Complex 5 reacted with [PdCl₂(NCPh) ₂] in a 2:1 molar ratio to form the C, N4, N1-coordinated tripalladium derivative [PdCl₂(PdCl(C, N4, N1-CH₂ C₈H₅N₂-5)(PPh₃)₂] (10). By contrast, when this reaction was carried out with an excess or equimolecular amount of PdCl₂(NCPh)₂] compound 3 was obtained together with [PdCl(μ-Cl)(PPh₃)]₂. We present evidence for formation of novel multimetallic species of the type [Pd(C, N4, N1-CH₂C₈H₅N₂-5) (PR₃)]_nX_n by reaction of 5 or 6 with TlOTf (OTf = O₃SCF₃), AgClO₄ or TlClO ₄. The crystal structures of 1 and 4·2CHCl₃ were determined by X-ray diffraction studies. They conclusively prove that Pd is coordinated to N(1) in 1 and to N(4) in 4.

Original language	English
Pages (from-to)	62-71
Number of pages	10
Journal	Journal of Organometalic Chemistry
Volume	648
Issue number	1-2
DOIs	https://doi.org/10.1016/S0022-328X(01)01394-8
Publication status	Published - 01 Apr 2002

Keywords

Cyclometallation
Methylquinoxaline
Palladium
X-ray diffraction

ASJC Scopus subject areas

Biochemistry
Physical and Theoretical Chemistry
Organic Chemistry
Inorganic Chemistry
Materials Chemistry

Access to Document

10.1016/S0022-328X(01)01394-8

Cite this

@article{6243761897404edfb2b1541ef6daa2d4,

title = "5-Methylquinoxaline as a versatile mono-, bi- and tridentate ligand in palladium(II) chemistry. Crystal structures of [Pd(OAc)(C, N4-CH2C8H5N2-5) (PPh 3)]",

abstract = "To study the potential coordination versatility of 5-methylquinoxaline, the preparation of complexes which contain it as a mono-, bi- or tridentate ligand was carried out. On reaction with [Pd(OAc)2] 3 it coordinates to the metal through its less sterically blocked nitrogen atom (N(1), distal to the Me group) to give trans-[Pd(OAc)2(N1-C8H5N2 Me-5)2] (1). Reflux of 1, or a mixture of [Pd(OAc)2]3 and 5-methylquinoxaline, in glacial acetic acid gave the cyclometallated acetate-bridged dimer [Pd(C, N4-CH2C8H5N2-5) (μ-OAc)]2 (2). Complex 2 reacted with: (i) LiCl to give [Pd(C, N4-CH2C8H5N2-5) (μ-Cl)]2 (3); (ii) PPh3 to give [Pd(C, N4-CH2C8H5N2-5) (OAc)(PPh3)] (4); (iii) PR3 and LiCl to give [Pd(C, N4-CH2C8H5N2-5)Cl (PR3)][R = Ph (5), Me (6), Et (7)]; (iv) Tl(acac) to give [Pd(C, N4-CH2C8H5N 2-5)(O, O-acac)] (8); and (v) 2,2′-bipyridine (bpy)-NaClO4H2O to give [Pd(C, N4-CH 2C8H5N2-5) (bpy)]ClO 4 (9). Complex 5 reacted with [PdCl2(NCPh) 2] in a 2:1 molar ratio to form the C, N4, N1-coordinated tripalladium derivative [PdCl2(PdCl(C, N4, N1-CH2 C8H5N2-5)(PPh3)2] (10). By contrast, when this reaction was carried out with an excess or equimolecular amount of PdCl2(NCPh)2] compound 3 was obtained together with [PdCl(μ-Cl)(PPh3)]2. We present evidence for formation of novel multimetallic species of the type [Pd(C, N4, N1-CH2C8H5N2-5) (PR3)]nXn by reaction of 5 or 6 with TlOTf (OTf = O3SCF3), AgClO4 or TlClO 4. The crystal structures of 1 and 4·2CHCl3 were determined by X-ray diffraction studies. They conclusively prove that Pd is coordinated to N(1) in 1 and to N(4) in 4.",

keywords = "Cyclometallation, Methylquinoxaline, Palladium, X-ray diffraction",

author = "Jos{\'e} Vicente and Lagunas, {M. Cristina} and Elke Bleuel and {Ram{\'i}rez De Arellano}, {M. Carmen}",

year = "2002",

month = apr,

day = "1",

doi = "10.1016/S0022-328X(01)01394-8",

language = "English",

volume = "648",

pages = "62--71",

journal = "Journal of Organometalic Chemistry",

issn = "0022-328X",

publisher = "Elsevier B.V.",

number = "1-2",

}

TY - JOUR

T1 - 5-Methylquinoxaline as a versatile mono-, bi- and tridentate ligand in palladium(II) chemistry. Crystal structures of [Pd(OAc)(C, N4-CH2C8H5N2-5) (PPh 3)]

AU - Vicente, José

AU - Lagunas, M. Cristina

AU - Bleuel, Elke

AU - Ramírez De Arellano, M. Carmen

PY - 2002/4/1

Y1 - 2002/4/1

N2 - To study the potential coordination versatility of 5-methylquinoxaline, the preparation of complexes which contain it as a mono-, bi- or tridentate ligand was carried out. On reaction with [Pd(OAc)2] 3 it coordinates to the metal through its less sterically blocked nitrogen atom (N(1), distal to the Me group) to give trans-[Pd(OAc)2(N1-C8H5N2 Me-5)2] (1). Reflux of 1, or a mixture of [Pd(OAc)2]3 and 5-methylquinoxaline, in glacial acetic acid gave the cyclometallated acetate-bridged dimer [Pd(C, N4-CH2C8H5N2-5) (μ-OAc)]2 (2). Complex 2 reacted with: (i) LiCl to give [Pd(C, N4-CH2C8H5N2-5) (μ-Cl)]2 (3); (ii) PPh3 to give [Pd(C, N4-CH2C8H5N2-5) (OAc)(PPh3)] (4); (iii) PR3 and LiCl to give [Pd(C, N4-CH2C8H5N2-5)Cl (PR3)][R = Ph (5), Me (6), Et (7)]; (iv) Tl(acac) to give [Pd(C, N4-CH2C8H5N 2-5)(O, O-acac)] (8); and (v) 2,2′-bipyridine (bpy)-NaClO4H2O to give [Pd(C, N4-CH 2C8H5N2-5) (bpy)]ClO 4 (9). Complex 5 reacted with [PdCl2(NCPh) 2] in a 2:1 molar ratio to form the C, N4, N1-coordinated tripalladium derivative [PdCl2(PdCl(C, N4, N1-CH2 C8H5N2-5)(PPh3)2] (10). By contrast, when this reaction was carried out with an excess or equimolecular amount of PdCl2(NCPh)2] compound 3 was obtained together with [PdCl(μ-Cl)(PPh3)]2. We present evidence for formation of novel multimetallic species of the type [Pd(C, N4, N1-CH2C8H5N2-5) (PR3)]nXn by reaction of 5 or 6 with TlOTf (OTf = O3SCF3), AgClO4 or TlClO 4. The crystal structures of 1 and 4·2CHCl3 were determined by X-ray diffraction studies. They conclusively prove that Pd is coordinated to N(1) in 1 and to N(4) in 4.

AB - To study the potential coordination versatility of 5-methylquinoxaline, the preparation of complexes which contain it as a mono-, bi- or tridentate ligand was carried out. On reaction with [Pd(OAc)2] 3 it coordinates to the metal through its less sterically blocked nitrogen atom (N(1), distal to the Me group) to give trans-[Pd(OAc)2(N1-C8H5N2 Me-5)2] (1). Reflux of 1, or a mixture of [Pd(OAc)2]3 and 5-methylquinoxaline, in glacial acetic acid gave the cyclometallated acetate-bridged dimer [Pd(C, N4-CH2C8H5N2-5) (μ-OAc)]2 (2). Complex 2 reacted with: (i) LiCl to give [Pd(C, N4-CH2C8H5N2-5) (μ-Cl)]2 (3); (ii) PPh3 to give [Pd(C, N4-CH2C8H5N2-5) (OAc)(PPh3)] (4); (iii) PR3 and LiCl to give [Pd(C, N4-CH2C8H5N2-5)Cl (PR3)][R = Ph (5), Me (6), Et (7)]; (iv) Tl(acac) to give [Pd(C, N4-CH2C8H5N 2-5)(O, O-acac)] (8); and (v) 2,2′-bipyridine (bpy)-NaClO4H2O to give [Pd(C, N4-CH 2C8H5N2-5) (bpy)]ClO 4 (9). Complex 5 reacted with [PdCl2(NCPh) 2] in a 2:1 molar ratio to form the C, N4, N1-coordinated tripalladium derivative [PdCl2(PdCl(C, N4, N1-CH2 C8H5N2-5)(PPh3)2] (10). By contrast, when this reaction was carried out with an excess or equimolecular amount of PdCl2(NCPh)2] compound 3 was obtained together with [PdCl(μ-Cl)(PPh3)]2. We present evidence for formation of novel multimetallic species of the type [Pd(C, N4, N1-CH2C8H5N2-5) (PR3)]nXn by reaction of 5 or 6 with TlOTf (OTf = O3SCF3), AgClO4 or TlClO 4. The crystal structures of 1 and 4·2CHCl3 were determined by X-ray diffraction studies. They conclusively prove that Pd is coordinated to N(1) in 1 and to N(4) in 4.

KW - Cyclometallation

KW - Methylquinoxaline

KW - Palladium

KW - X-ray diffraction

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DO - 10.1016/S0022-328X(01)01394-8

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VL - 648

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JO - Journal of Organometalic Chemistry

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