Periphery-palladated carbosilane dendrimers: Synthesis and reactivity of organopalladium(II) and -(IV) dendritic complexes. Crystal structure of [PdMe(C6H4(OCH2Ph)-4)(bpy)] (bpy = 2,2′-bipyridine)

Neides J. Hovestad; Jason L. Hoare; Johann T B H Jastrzebski; Allan J. Canty; Wilberth J J Smeets; Anthony L. Spek; Gerard Van Koten

Periphery-palladated carbosilane dendrimers: Synthesis and reactivity of organopalladium(II) and -(IV) dendritic complexes. Crystal structure of [PdMe(C6H4(OCH2Ph)-4)(bpy)] (bpy = 2,2′-bipyridine)

Neides J. Hovestad, Jason L. Hoare, Johann T B H Jastrzebski, Allan J. Canty, Wilberth J J Smeets, Anthony L. Spek, Gerard Van Koten^*

^*Corresponding author for this work

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

Abstract

A carbosilane dendrimer with 12 peripheral iodoarene groups, [Si{(CH₂)₃Si((CH₂)₃-SiMe ₂(C₆H₄CH₂OC₆H ₄I-4))₃}₄] (G₁-ArI, 9), and the corresponding G₀ model compound [Si-{(CH₂)₃SiMe₂(C₆H ₄CH₂OC₆H₄I-4)}₄] (G₀-ArI, 8) have been prepared from [Si{(CH₂)₃Si((CH₂)₃-SiMe ₂(C₆H₄CH₂Br))₃} ₄] (G₁-Br, 7) and the corresponding G₀ model compound [Si{(CH₂)₃SiMe₂-(C₆H ₄CH₂Br)}₄] (G₀-Br, 6). These dendritic species react with [Pd₂(dba)₃·dba/tmeda] (dba = dibenzylideneacetone, tmeda = N,N,N′,N′-tetramethylethylenediamine) to yield the periphery-palladated complexes [Si{(CH₂)₃SiMe₂(C₆H ₄CH₂O(C₆H₄-4)PdI(tmeda))} ₄] (G₀-ArPdI(tmeda), 10) and [Si{(CH₂)₃Si((CH₂)₃SiMe ₂(C₆H₄CH₂O(C₆H ₄-4)PdI(tmeda))3}4] (G₁-ArPdI(tmeda), 11). Complexes 10 and 11 react with LiMe and 2,2′-bipyridine (bpy) to yield the air-stable [Si-{(CH₂)₃SiMe₂(C₆H ₄CH₂OC₆H₄PdMe(bpy))}₄] (G₀-PdMe(bpy), 12) and [Si{(CH₂)₃Si((CH₂)₃-SiMe ₂(C₆H₄CH₂OC₆H ₄PdMe(bpy)))₃}₄] (G₁-ArPdMe(bpy), 13). Complexes 12 and 13 undergo oxidative addition with benzyl bromide to form species containing Pd(IV) centers. These complexes can undergo subsequent reductive elimination at ambient temperature involving both Me-Ar and Me-CH₂Ph coupling on decomposition. Iodoarenes that model the arms of carbosilane-based dendrimers have been synthesized, and procedures have been developed for maximizing yields of organopalladium(II) and -(IV) derivatives of the iodoarenes as part of a program directed toward the isolation and study of organopalladium functionalized dendrimers. The iodoarenes RC₆H₄(CH₂OC₆H ₄I-4′)-4 (R = H (1a), SiMe₃ (1b)) were obtained and found to undergo facile oxidative addition to [Pd₂(dba)₃·dba/tmeda] to form [PdI(Ar)-(tmeda)] (2a,b), which react with LiMe to form [PdMe(Ar)(tmeda)] (3a,b). Bpy displaces tmeda to form [PdMe(Ar)(bpy)] (4a,b), and the latter complexes undergo oxidative addition with benzyl bromide to form the complexes [PdBrMeAr(CH₂Ph)(bpy)] (5a,b). The palladium-(IV) complex 5a undergoes facile and clean reductive elimination at ambient temperature in CDCl₃ to form the coupling products Me-C₆H₄(OCH₂Ph)-4 (89%), PhCH₂-C₆H₄(OCH₂Ph)-4 (9%), and Me-CH₂Ph (2%). However, 5b undergoes more complex behavior to form Me-C₆H₄-(OCH₂C₆H ₄(SiMe₃)-4′)-4 (87%), Me-CH₂Ph (6%), and PhCH₂-CH₂Ph (7%) together with [PdBr₂(bpy)]. The complex [PdMe(C₆H₄(OCH₂Ph)-4)(bpy)] (4a) has been characterized by X-ray diffraction. The asymmetric unit contains two similar but crystallographically independent molecules. Each molecule has square-planar geometry for palladium with the aryl ring tilted by 76.2(4) and 67.1(3)° to the coordination plane, respectively. The crystal examined by X-ray diffraction exhibits significant substitutional disorder at one site: [PdX-(C₆H₄(OCH₂Ph)-4)(bpy)] (X = Me (71%), Cl (29%)).

Original language	English
Pages (from-to)	2970-2980
Number of pages	11
Journal	Organometallics
Volume	18
Issue number	16
Publication status	Published - 2 Aug 1999

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@article{212b867dbd9742dbbf81e7ddc4d40fa0,

title = "Periphery-palladated carbosilane dendrimers: Synthesis and reactivity of organopalladium(II) and -(IV) dendritic complexes. Crystal structure of [PdMe(C6H4(OCH2Ph)-4)(bpy)] (bpy = 2,2′-bipyridine)",

abstract = "A carbosilane dendrimer with 12 peripheral iodoarene groups, [Si{(CH2)3Si((CH2)3-SiMe 2(C6H4CH2OC6H 4I-4))3}4] (G1-ArI, 9), and the corresponding G0 model compound [Si-{(CH2)3SiMe2(C6H 4CH2OC6H4I-4)}4] (G0-ArI, 8) have been prepared from [Si{(CH2)3Si((CH2)3-SiMe 2(C6H4CH2Br))3} 4] (G1-Br, 7) and the corresponding G0 model compound [Si{(CH2)3SiMe2-(C6H 4CH2Br)}4] (G0-Br, 6). These dendritic species react with [Pd2(dba)3·dba/tmeda] (dba = dibenzylideneacetone, tmeda = N,N,N′,N′-tetramethylethylenediamine) to yield the periphery-palladated complexes [Si{(CH2)3SiMe2(C6H 4CH2O(C6H4-4)PdI(tmeda))} 4] (G0-ArPdI(tmeda), 10) and [Si{(CH2)3Si((CH2)3SiMe 2(C6H4CH2O(C6H 4-4)PdI(tmeda))3}4] (G1-ArPdI(tmeda), 11). Complexes 10 and 11 react with LiMe and 2,2′-bipyridine (bpy) to yield the air-stable [Si-{(CH2)3SiMe2(C6H 4CH2OC6H4PdMe(bpy))}4] (G0-PdMe(bpy), 12) and [Si{(CH2)3Si((CH2)3-SiMe 2(C6H4CH2OC6H 4PdMe(bpy)))3}4] (G1-ArPdMe(bpy), 13). Complexes 12 and 13 undergo oxidative addition with benzyl bromide to form species containing Pd(IV) centers. These complexes can undergo subsequent reductive elimination at ambient temperature involving both Me-Ar and Me-CH2Ph coupling on decomposition. Iodoarenes that model the arms of carbosilane-based dendrimers have been synthesized, and procedures have been developed for maximizing yields of organopalladium(II) and -(IV) derivatives of the iodoarenes as part of a program directed toward the isolation and study of organopalladium functionalized dendrimers. The iodoarenes RC6H4(CH2OC6H 4I-4′)-4 (R = H (1a), SiMe3 (1b)) were obtained and found to undergo facile oxidative addition to [Pd2(dba)3·dba/tmeda] to form [PdI(Ar)-(tmeda)] (2a,b), which react with LiMe to form [PdMe(Ar)(tmeda)] (3a,b). Bpy displaces tmeda to form [PdMe(Ar)(bpy)] (4a,b), and the latter complexes undergo oxidative addition with benzyl bromide to form the complexes [PdBrMeAr(CH2Ph)(bpy)] (5a,b). The palladium-(IV) complex 5a undergoes facile and clean reductive elimination at ambient temperature in CDCl3 to form the coupling products Me-C6H4(OCH2Ph)-4 (89%), PhCH2-C6H4(OCH2Ph)-4 (9%), and Me-CH2Ph (2%). However, 5b undergoes more complex behavior to form Me-C6H4-(OCH2C6H 4(SiMe3)-4′)-4 (87%), Me-CH2Ph (6%), and PhCH2-CH2Ph (7%) together with [PdBr2(bpy)]. The complex [PdMe(C6H4(OCH2Ph)-4)(bpy)] (4a) has been characterized by X-ray diffraction. The asymmetric unit contains two similar but crystallographically independent molecules. Each molecule has square-planar geometry for palladium with the aryl ring tilted by 76.2(4) and 67.1(3)° to the coordination plane, respectively. The crystal examined by X-ray diffraction exhibits significant substitutional disorder at one site: [PdX-(C6H4(OCH2Ph)-4)(bpy)] (X = Me (71%), Cl (29%)).",

author = "Hovestad, {Neides J.} and Hoare, {Jason L.} and Jastrzebski, {Johann T B H} and Canty, {Allan J.} and Smeets, {Wilberth J J} and Spek, {Anthony L.} and {Van Koten}, Gerard",

year = "1999",

month = aug,

day = "2",

language = "English",

volume = "18",

pages = "2970--2980",

journal = "Organometallics",

issn = "0276-7333",

publisher = "American Chemical Society",

number = "16",

}

Periphery-palladated carbosilane dendrimers: Synthesis and reactivity of organopalladium(II) and -(IV) dendritic complexes. Crystal structure of [PdMe(C6H4(OCH2Ph)-4)(bpy)] (bpy = 2,2′-bipyridine). / Hovestad, Neides J.; Hoare, Jason L.; Jastrzebski, Johann T B H et al.
In: Organometallics, Vol. 18, No. 16, 02.08.1999, p. 2970-2980.

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

TY - JOUR

T1 - Periphery-palladated carbosilane dendrimers

T2 - Synthesis and reactivity of organopalladium(II) and -(IV) dendritic complexes. Crystal structure of [PdMe(C6H4(OCH2Ph)-4)(bpy)] (bpy = 2,2′-bipyridine)

AU - Hovestad, Neides J.

AU - Hoare, Jason L.

AU - Jastrzebski, Johann T B H

AU - Canty, Allan J.

AU - Smeets, Wilberth J J

AU - Spek, Anthony L.

AU - Van Koten, Gerard

PY - 1999/8/2

Y1 - 1999/8/2

N2 - A carbosilane dendrimer with 12 peripheral iodoarene groups, [Si{(CH2)3Si((CH2)3-SiMe 2(C6H4CH2OC6H 4I-4))3}4] (G1-ArI, 9), and the corresponding G0 model compound [Si-{(CH2)3SiMe2(C6H 4CH2OC6H4I-4)}4] (G0-ArI, 8) have been prepared from [Si{(CH2)3Si((CH2)3-SiMe 2(C6H4CH2Br))3} 4] (G1-Br, 7) and the corresponding G0 model compound [Si{(CH2)3SiMe2-(C6H 4CH2Br)}4] (G0-Br, 6). These dendritic species react with [Pd2(dba)3·dba/tmeda] (dba = dibenzylideneacetone, tmeda = N,N,N′,N′-tetramethylethylenediamine) to yield the periphery-palladated complexes [Si{(CH2)3SiMe2(C6H 4CH2O(C6H4-4)PdI(tmeda))} 4] (G0-ArPdI(tmeda), 10) and [Si{(CH2)3Si((CH2)3SiMe 2(C6H4CH2O(C6H 4-4)PdI(tmeda))3}4] (G1-ArPdI(tmeda), 11). Complexes 10 and 11 react with LiMe and 2,2′-bipyridine (bpy) to yield the air-stable [Si-{(CH2)3SiMe2(C6H 4CH2OC6H4PdMe(bpy))}4] (G0-PdMe(bpy), 12) and [Si{(CH2)3Si((CH2)3-SiMe 2(C6H4CH2OC6H 4PdMe(bpy)))3}4] (G1-ArPdMe(bpy), 13). Complexes 12 and 13 undergo oxidative addition with benzyl bromide to form species containing Pd(IV) centers. These complexes can undergo subsequent reductive elimination at ambient temperature involving both Me-Ar and Me-CH2Ph coupling on decomposition. Iodoarenes that model the arms of carbosilane-based dendrimers have been synthesized, and procedures have been developed for maximizing yields of organopalladium(II) and -(IV) derivatives of the iodoarenes as part of a program directed toward the isolation and study of organopalladium functionalized dendrimers. The iodoarenes RC6H4(CH2OC6H 4I-4′)-4 (R = H (1a), SiMe3 (1b)) were obtained and found to undergo facile oxidative addition to [Pd2(dba)3·dba/tmeda] to form [PdI(Ar)-(tmeda)] (2a,b), which react with LiMe to form [PdMe(Ar)(tmeda)] (3a,b). Bpy displaces tmeda to form [PdMe(Ar)(bpy)] (4a,b), and the latter complexes undergo oxidative addition with benzyl bromide to form the complexes [PdBrMeAr(CH2Ph)(bpy)] (5a,b). The palladium-(IV) complex 5a undergoes facile and clean reductive elimination at ambient temperature in CDCl3 to form the coupling products Me-C6H4(OCH2Ph)-4 (89%), PhCH2-C6H4(OCH2Ph)-4 (9%), and Me-CH2Ph (2%). However, 5b undergoes more complex behavior to form Me-C6H4-(OCH2C6H 4(SiMe3)-4′)-4 (87%), Me-CH2Ph (6%), and PhCH2-CH2Ph (7%) together with [PdBr2(bpy)]. The complex [PdMe(C6H4(OCH2Ph)-4)(bpy)] (4a) has been characterized by X-ray diffraction. The asymmetric unit contains two similar but crystallographically independent molecules. Each molecule has square-planar geometry for palladium with the aryl ring tilted by 76.2(4) and 67.1(3)° to the coordination plane, respectively. The crystal examined by X-ray diffraction exhibits significant substitutional disorder at one site: [PdX-(C6H4(OCH2Ph)-4)(bpy)] (X = Me (71%), Cl (29%)).

AB - A carbosilane dendrimer with 12 peripheral iodoarene groups, [Si{(CH2)3Si((CH2)3-SiMe 2(C6H4CH2OC6H 4I-4))3}4] (G1-ArI, 9), and the corresponding G0 model compound [Si-{(CH2)3SiMe2(C6H 4CH2OC6H4I-4)}4] (G0-ArI, 8) have been prepared from [Si{(CH2)3Si((CH2)3-SiMe 2(C6H4CH2Br))3} 4] (G1-Br, 7) and the corresponding G0 model compound [Si{(CH2)3SiMe2-(C6H 4CH2Br)}4] (G0-Br, 6). These dendritic species react with [Pd2(dba)3·dba/tmeda] (dba = dibenzylideneacetone, tmeda = N,N,N′,N′-tetramethylethylenediamine) to yield the periphery-palladated complexes [Si{(CH2)3SiMe2(C6H 4CH2O(C6H4-4)PdI(tmeda))} 4] (G0-ArPdI(tmeda), 10) and [Si{(CH2)3Si((CH2)3SiMe 2(C6H4CH2O(C6H 4-4)PdI(tmeda))3}4] (G1-ArPdI(tmeda), 11). Complexes 10 and 11 react with LiMe and 2,2′-bipyridine (bpy) to yield the air-stable [Si-{(CH2)3SiMe2(C6H 4CH2OC6H4PdMe(bpy))}4] (G0-PdMe(bpy), 12) and [Si{(CH2)3Si((CH2)3-SiMe 2(C6H4CH2OC6H 4PdMe(bpy)))3}4] (G1-ArPdMe(bpy), 13). Complexes 12 and 13 undergo oxidative addition with benzyl bromide to form species containing Pd(IV) centers. These complexes can undergo subsequent reductive elimination at ambient temperature involving both Me-Ar and Me-CH2Ph coupling on decomposition. Iodoarenes that model the arms of carbosilane-based dendrimers have been synthesized, and procedures have been developed for maximizing yields of organopalladium(II) and -(IV) derivatives of the iodoarenes as part of a program directed toward the isolation and study of organopalladium functionalized dendrimers. The iodoarenes RC6H4(CH2OC6H 4I-4′)-4 (R = H (1a), SiMe3 (1b)) were obtained and found to undergo facile oxidative addition to [Pd2(dba)3·dba/tmeda] to form [PdI(Ar)-(tmeda)] (2a,b), which react with LiMe to form [PdMe(Ar)(tmeda)] (3a,b). Bpy displaces tmeda to form [PdMe(Ar)(bpy)] (4a,b), and the latter complexes undergo oxidative addition with benzyl bromide to form the complexes [PdBrMeAr(CH2Ph)(bpy)] (5a,b). The palladium-(IV) complex 5a undergoes facile and clean reductive elimination at ambient temperature in CDCl3 to form the coupling products Me-C6H4(OCH2Ph)-4 (89%), PhCH2-C6H4(OCH2Ph)-4 (9%), and Me-CH2Ph (2%). However, 5b undergoes more complex behavior to form Me-C6H4-(OCH2C6H 4(SiMe3)-4′)-4 (87%), Me-CH2Ph (6%), and PhCH2-CH2Ph (7%) together with [PdBr2(bpy)]. The complex [PdMe(C6H4(OCH2Ph)-4)(bpy)] (4a) has been characterized by X-ray diffraction. The asymmetric unit contains two similar but crystallographically independent molecules. Each molecule has square-planar geometry for palladium with the aryl ring tilted by 76.2(4) and 67.1(3)° to the coordination plane, respectively. The crystal examined by X-ray diffraction exhibits significant substitutional disorder at one site: [PdX-(C6H4(OCH2Ph)-4)(bpy)] (X = Me (71%), Cl (29%)).

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M3 - Article

AN - SCOPUS:0001537870

SN - 0276-7333

VL - 18

SP - 2970

EP - 2980

JO - Organometallics

JF - Organometallics

IS - 16

ER -

Periphery-palladated carbosilane dendrimers: Synthesis and reactivity of organopalladium(II) and -(IV) dendritic complexes. Crystal structure of [PdMe(C6H4(OCH2Ph)-4)(bpy)] (bpy = 2,2′-bipyridine)

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