Dihydrobis(pyrazolyl)borate alkylidyne complexes of tungsten

Anthony F. Hill; John M. Malget; Andrew J.P. White; David J. Williams

doi:10.1002/ejic.200300444

Dihydrobis(pyrazolyl)borate alkylidyne complexes of tungsten

Anthony F. Hill^*, John M. Malget, Andrew J.P. White, David J. Williams

^*Corresponding author for this work

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

20 Citations (Scopus)

Abstract

[W(≡CR)Br(CO)₂(NC₅H₄Me-4) ₂] (R = C₆H₃Me₂-2,6 1a, C ₆H₂Me₃-2,4,6 1b) react with K[H ₂B(pz)₂] (pz = pyrazol-1-y1) to provide two interconverting isomers of [W(≡CR)(CO)₂(NC₅H ₄Me-4){H₂B(pz)₂}] (2), one isomer having been structurally characterised for R = C₆H₃Me₂-2,6 (2a). The reactions of [W(≡CR)Br(CO)₂(CNR′)₂] (5: R′ = C₆H₃Me₂-2,6, CNMe₃) with K[H₂B(pz)₂] or of [W(≡CR)Br(CO) ₂(NC₅H₄Me-4){H₂B(pz)₂}] (2) with isocyanides are more complex due to the facile formation of unstable ketenyl derivatives. In the absence of light, the reaction of [W(≡CR)Br(CO)₂(CNR′)₂] (5) with K[H ₂B(pz)₂] provides [W(≡CR)(CO)₂(CNR′ ){H₂B(pz)₂}] (3) in moderate yield, similar yields were obtained from [W(∼CR)(CO)₂(NC₅H₄Me-4) {H₂B(pz)₂}] (2) and CNR′. Under mild photolytic conditions both combinations provide primarily the thermally unstable ketenyl complex [W(η²-OCCR)(CO)(CNR′)₂{H ₂B(pz)₂}] (4). The picoline ligand in [W(≡CR)Br(CO) ₂(NC₅H₄Me-₄){H₂B(pz) ₂}] (2) is readily replaced by PMe₂Ph to provide [W(≡CR)(CO)₂(PMe₂Ph){H₂B(pz) ₂}] (structurally characterised for R = C₆H ₃Me₂-2,6 6a). The reaction of either [W(≡CR)(CO) ₂(PMe₂Ph){H₂B(pz)₂}] (6) or [W(≡CR)-(CO)₂(NC₅H₄Me- ₄){H₂B{pz)₂}] (R= C₆H ₂Me₃-2,4,6 2b) with excess PMe₂Ph provides [W(≡CR)(CO)(PMe₂Ph)₂[H₂B(pz) ₂}] (7). This complex is also obtained from K[H₂B(pz) ₂] and [W(≡CR)Br(CO)(PMe₂Ph)₃] (8), the latter arising from the reaction of [W(≡CR)Br(CO)₂(NC ₅H₄Me-4)₂] (1b) with PMe₂Ph.

Original language	English
Pages (from-to)	818-828
Number of pages	11
Journal	European Journal of Inorganic Chemistry
Issue number	4
DOIs	https://doi.org/10.1002/ejic.200300444
Publication status	Published - 20 Feb 2004

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@article{1b9ed98be09c4267aff148495d4bb219,

title = "Dihydrobis(pyrazolyl)borate alkylidyne complexes of tungsten",

abstract = "[W(≡CR)Br(CO)2(NC5H4Me-4) 2] (R = C6H3Me2-2,6 1a, C 6H2Me3-2,4,6 1b) react with K[H 2B(pz)2] (pz = pyrazol-1-y1) to provide two interconverting isomers of [W(≡CR)(CO)2(NC5H 4Me-4){H2B(pz)2}] (2), one isomer having been structurally characterised for R = C6H3Me2-2,6 (2a). The reactions of [W(≡CR)Br(CO)2(CNR′)2] (5: R′ = C6H3Me2-2,6, CNMe3) with K[H2B(pz)2] or of [W(≡CR)Br(CO) 2(NC5H4Me-4){H2B(pz)2}] (2) with isocyanides are more complex due to the facile formation of unstable ketenyl derivatives. In the absence of light, the reaction of [W(≡CR)Br(CO)2(CNR′)2] (5) with K[H 2B(pz)2] provides [W(≡CR)(CO)2(CNR′ ){H2B(pz)2}] (3) in moderate yield, similar yields were obtained from [W(∼CR)(CO)2(NC5H4Me-4) {H2B(pz)2}] (2) and CNR′. Under mild photolytic conditions both combinations provide primarily the thermally unstable ketenyl complex [W(η2-OCCR)(CO)(CNR′)2{H 2B(pz)2}] (4). The picoline ligand in [W(≡CR)Br(CO) 2(NC5H4Me-4){H2B(pz) 2}] (2) is readily replaced by PMe2Ph to provide [W(≡CR)(CO)2(PMe2Ph){H2B(pz) 2}] (structurally characterised for R = C6H 3Me2-2,6 6a). The reaction of either [W(≡CR)(CO) 2(PMe2Ph){H2B(pz)2}] (6) or [W(≡CR)-(CO)2(NC5H4Me- 4){H2B{pz)2}] (R= C6H 2Me3-2,4,6 2b) with excess PMe2Ph provides [W(≡CR)(CO)(PMe2Ph)2[H2B(pz) 2}] (7). This complex is also obtained from K[H2B(pz) 2] and [W(≡CR)Br(CO)(PMe2Ph)3] (8), the latter arising from the reaction of [W(≡CR)Br(CO)2(NC 5H4Me-4)2] (1b) with PMe2Ph.",

keywords = "Borates, Carbyne ligands, Multiple bonds, N Ligands, Tungsten",

author = "Hill, {Anthony F.} and Malget, {John M.} and White, {Andrew J.P.} and Williams, {David J.}",

year = "2004",

month = feb,

day = "20",

doi = "10.1002/ejic.200300444",

language = "English",

pages = "818--828",

journal = "European Journal of Inorganic Chemistry",

issn = "1434-1948",

publisher = "Wiley-VCH Verlag GmbH",

number = "4",

}

TY - JOUR

T1 - Dihydrobis(pyrazolyl)borate alkylidyne complexes of tungsten

AU - Hill, Anthony F.

AU - Malget, John M.

AU - White, Andrew J.P.

AU - Williams, David J.

PY - 2004/2/20

Y1 - 2004/2/20

N2 - [W(≡CR)Br(CO)2(NC5H4Me-4) 2] (R = C6H3Me2-2,6 1a, C 6H2Me3-2,4,6 1b) react with K[H 2B(pz)2] (pz = pyrazol-1-y1) to provide two interconverting isomers of [W(≡CR)(CO)2(NC5H 4Me-4){H2B(pz)2}] (2), one isomer having been structurally characterised for R = C6H3Me2-2,6 (2a). The reactions of [W(≡CR)Br(CO)2(CNR′)2] (5: R′ = C6H3Me2-2,6, CNMe3) with K[H2B(pz)2] or of [W(≡CR)Br(CO) 2(NC5H4Me-4){H2B(pz)2}] (2) with isocyanides are more complex due to the facile formation of unstable ketenyl derivatives. In the absence of light, the reaction of [W(≡CR)Br(CO)2(CNR′)2] (5) with K[H 2B(pz)2] provides [W(≡CR)(CO)2(CNR′ ){H2B(pz)2}] (3) in moderate yield, similar yields were obtained from [W(∼CR)(CO)2(NC5H4Me-4) {H2B(pz)2}] (2) and CNR′. Under mild photolytic conditions both combinations provide primarily the thermally unstable ketenyl complex [W(η2-OCCR)(CO)(CNR′)2{H 2B(pz)2}] (4). The picoline ligand in [W(≡CR)Br(CO) 2(NC5H4Me-4){H2B(pz) 2}] (2) is readily replaced by PMe2Ph to provide [W(≡CR)(CO)2(PMe2Ph){H2B(pz) 2}] (structurally characterised for R = C6H 3Me2-2,6 6a). The reaction of either [W(≡CR)(CO) 2(PMe2Ph){H2B(pz)2}] (6) or [W(≡CR)-(CO)2(NC5H4Me- 4){H2B{pz)2}] (R= C6H 2Me3-2,4,6 2b) with excess PMe2Ph provides [W(≡CR)(CO)(PMe2Ph)2[H2B(pz) 2}] (7). This complex is also obtained from K[H2B(pz) 2] and [W(≡CR)Br(CO)(PMe2Ph)3] (8), the latter arising from the reaction of [W(≡CR)Br(CO)2(NC 5H4Me-4)2] (1b) with PMe2Ph.

AB - [W(≡CR)Br(CO)2(NC5H4Me-4) 2] (R = C6H3Me2-2,6 1a, C 6H2Me3-2,4,6 1b) react with K[H 2B(pz)2] (pz = pyrazol-1-y1) to provide two interconverting isomers of [W(≡CR)(CO)2(NC5H 4Me-4){H2B(pz)2}] (2), one isomer having been structurally characterised for R = C6H3Me2-2,6 (2a). The reactions of [W(≡CR)Br(CO)2(CNR′)2] (5: R′ = C6H3Me2-2,6, CNMe3) with K[H2B(pz)2] or of [W(≡CR)Br(CO) 2(NC5H4Me-4){H2B(pz)2}] (2) with isocyanides are more complex due to the facile formation of unstable ketenyl derivatives. In the absence of light, the reaction of [W(≡CR)Br(CO)2(CNR′)2] (5) with K[H 2B(pz)2] provides [W(≡CR)(CO)2(CNR′ ){H2B(pz)2}] (3) in moderate yield, similar yields were obtained from [W(∼CR)(CO)2(NC5H4Me-4) {H2B(pz)2}] (2) and CNR′. Under mild photolytic conditions both combinations provide primarily the thermally unstable ketenyl complex [W(η2-OCCR)(CO)(CNR′)2{H 2B(pz)2}] (4). The picoline ligand in [W(≡CR)Br(CO) 2(NC5H4Me-4){H2B(pz) 2}] (2) is readily replaced by PMe2Ph to provide [W(≡CR)(CO)2(PMe2Ph){H2B(pz) 2}] (structurally characterised for R = C6H 3Me2-2,6 6a). The reaction of either [W(≡CR)(CO) 2(PMe2Ph){H2B(pz)2}] (6) or [W(≡CR)-(CO)2(NC5H4Me- 4){H2B{pz)2}] (R= C6H 2Me3-2,4,6 2b) with excess PMe2Ph provides [W(≡CR)(CO)(PMe2Ph)2[H2B(pz) 2}] (7). This complex is also obtained from K[H2B(pz) 2] and [W(≡CR)Br(CO)(PMe2Ph)3] (8), the latter arising from the reaction of [W(≡CR)Br(CO)2(NC 5H4Me-4)2] (1b) with PMe2Ph.

KW - Borates

KW - Carbyne ligands

KW - Multiple bonds

KW - N Ligands

KW - Tungsten

UR - http://www.scopus.com/inward/record.url?scp=2942572471&partnerID=8YFLogxK

U2 - 10.1002/ejic.200300444

DO - 10.1002/ejic.200300444

M3 - Article

SN - 1434-1948

SP - 818

EP - 828

JO - European Journal of Inorganic Chemistry

JF - European Journal of Inorganic Chemistry

IS - 4

ER -

Dihydrobis(pyrazolyl)borate alkylidyne complexes of tungsten

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