Molybdenum and tungsten structural differences are dependent on nd(Z)(2)/(n+1)s mixing: Comparisons of (silox)(3)MX/R (M = Mo, W; silox = (Bu3SiO)-Bu-t)

David S. Kuiper; Richard E. Douthwaite; Ana-Rita Mayol; Peter T. Wolczanski; Emil B. Lobkovsky; Thomas R. Cundari; Oanh P. Lam; Karsten Meyer

doi:10.1021/ic800139c

Molybdenum and tungsten structural differences are dependent on nd(Z)(2)/(n+1)s mixing: Comparisons of (silox)(3)MX/R (M = Mo, W; silox = (Bu3SiO)-Bu-t)

David S. Kuiper, Richard E. Douthwaite, Ana-Rita Mayol, Peter T. Wolczanski, Emil B. Lobkovsky, Thomas R. Cundari, Oanh P. Lam, Karsten Meyer

Chemistry

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

Abstract

Treatment of trans-(Et2O)(2)MoCl4 with 2 or 3 equiv of Na(silox) (i.e., (NaOSiBu3)-Bu-t) afforded (Silox)(3)MoCl2 (1-Mo) or (silox)(3)MoCl (2-Mo). Purification of 2-Mo was accomplished via addition of PMe3 to precipitate (Silox)(3)CIMoPMe3 (2-MoPMe3), followed by thermolysis to remove phosphine. Use of MoCl3(THF)(3) with various amounts of Na(silox) produced (Silox)(2)ClMoMoCl(Silox)(2) (3-Mo). Alkylation of 2-Mo with MeMgBr or EtMgBr afforded (Silox)(3)MoR (R = Me, 2-MoMe; Et, 2-MoEt). 2-MoEt was also synthesized from C2H4 and (Silox)(3)MoH, which was prepared from 2-Mo and NaBEt3H. Thermolysis of WCl6 with (HOSiBu3)-Bu-t afforded (Silox)(2)WCl4 (4-W), and sequential treatment of 4-W with Na/Hg and Na(silox) provided (Silox)(3)WCl2 (1-W, tbp, X-ray), which was alternatively prepared from trans-(Et2S)(2) WCl4 and 3 equiv of Tl(silox). Na/Hg reduction of 1-W generated (silox)(3)WCl (2-W). Alkylation of 2-W with MeMgBr produced (Silox)(3)WMe (2-WMe), which dehydrogenated to (Silox)(3)WCH (6-W) with Delta H-double dagger = 14.9(9) kcal/ mol and Delta S-double dagger = -26(2) eu. Magnetism and structural studies revealed that 2-Mo and 2-MoEt have triplet ground states (GS) and distorted trigonal monopyramid (tmp) and tmp structures, respectively. In contrast, 2-W and 2-WMe possess squashed-T-d (distorted square planar) structures, and the former has a singlet GS. Quantum mechanics/ molecular mechanics studies of the S = 0 and S = 1 states for full models of 2-Mo, 2-MoEt, 2-W and 2-WMe corroborate the experimental findings and are consistent with the greater nd(z)(2)/(n + 1)s mixing in the third-row transition-metal species being the dominant feature in determining the structural disparity between molybdenum and tungsten.

Original language	English
Pages (from-to)	7139-7153
Number of pages	15
Journal	Inorganic Chemistry
Volume	47
Issue number	16
DOIs	https://doi.org/10.1021/ic800139c
Publication status	Published - 18 Aug 2008

Keywords

FORBIDDEN CHEMICAL-REACTIONS
TRANSITION-METAL-COMPLEXES
OPEN-SHELL ORGANOMETALLICS
ELECTRONIC-STRUCTURE
BIS(DITHIOLENE) COMPLEXES
REACTION SYSTEMS
ALKYL COMPLEXES
BOND ACTIVATION
ATOM-TRANSFER
C-H

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@article{59b6d9c3120b494ba7a50845666b5171,

title = "Molybdenum and tungsten structural differences are dependent on nd(Z)(2)/(n+1)s mixing: Comparisons of (silox)(3)MX/R (M = Mo, W; silox = (Bu3SiO)-Bu-t)",

abstract = "Treatment of trans-(Et2O)(2)MoCl4 with 2 or 3 equiv of Na(silox) (i.e., (NaOSiBu3)-Bu-t) afforded (Silox)(3)MoCl2 (1-Mo) or (silox)(3)MoCl (2-Mo). Purification of 2-Mo was accomplished via addition of PMe3 to precipitate (Silox)(3)CIMoPMe3 (2-MoPMe3), followed by thermolysis to remove phosphine. Use of MoCl3(THF)(3) with various amounts of Na(silox) produced (Silox)(2)ClMoMoCl(Silox)(2) (3-Mo). Alkylation of 2-Mo with MeMgBr or EtMgBr afforded (Silox)(3)MoR (R = Me, 2-MoMe; Et, 2-MoEt). 2-MoEt was also synthesized from C2H4 and (Silox)(3)MoH, which was prepared from 2-Mo and NaBEt3H. Thermolysis of WCl6 with (HOSiBu3)-Bu-t afforded (Silox)(2)WCl4 (4-W), and sequential treatment of 4-W with Na/Hg and Na(silox) provided (Silox)(3)WCl2 (1-W, tbp, X-ray), which was alternatively prepared from trans-(Et2S)(2) WCl4 and 3 equiv of Tl(silox). Na/Hg reduction of 1-W generated (silox)(3)WCl (2-W). Alkylation of 2-W with MeMgBr produced (Silox)(3)WMe (2-WMe), which dehydrogenated to (Silox)(3)WCH (6-W) with Delta H-double dagger = 14.9(9) kcal/ mol and Delta S-double dagger = -26(2) eu. Magnetism and structural studies revealed that 2-Mo and 2-MoEt have triplet ground states (GS) and distorted trigonal monopyramid (tmp) and tmp structures, respectively. In contrast, 2-W and 2-WMe possess squashed-T-d (distorted square planar) structures, and the former has a singlet GS. Quantum mechanics/ molecular mechanics studies of the S = 0 and S = 1 states for full models of 2-Mo, 2-MoEt, 2-W and 2-WMe corroborate the experimental findings and are consistent with the greater nd(z)(2)/(n + 1)s mixing in the third-row transition-metal species being the dominant feature in determining the structural disparity between molybdenum and tungsten.",

keywords = "FORBIDDEN CHEMICAL-REACTIONS, TRANSITION-METAL-COMPLEXES, OPEN-SHELL ORGANOMETALLICS, ELECTRONIC-STRUCTURE, BIS(DITHIOLENE) COMPLEXES, REACTION SYSTEMS, ALKYL COMPLEXES, BOND ACTIVATION, ATOM-TRANSFER, C-H",

author = "Kuiper, {David S.} and Douthwaite, {Richard E.} and Ana-Rita Mayol and Wolczanski, {Peter T.} and Lobkovsky, {Emil B.} and Cundari, {Thomas R.} and Lam, {Oanh P.} and Karsten Meyer",

year = "2008",

month = aug,

day = "18",

doi = "10.1021/ic800139c",

language = "English",

volume = "47",

pages = "7139--7153",

journal = "Inorganic Chemistry",

issn = "0020-1669",

publisher = "American Chemical Society",

number = "16",

}

TY - JOUR

T1 - Molybdenum and tungsten structural differences are dependent on nd(Z)(2)/(n+1)s mixing: Comparisons of (silox)(3)MX/R (M = Mo, W; silox = (Bu3SiO)-Bu-t)

AU - Kuiper, David S.

AU - Douthwaite, Richard E.

AU - Mayol, Ana-Rita

AU - Wolczanski, Peter T.

AU - Lobkovsky, Emil B.

AU - Cundari, Thomas R.

AU - Lam, Oanh P.

AU - Meyer, Karsten

PY - 2008/8/18

Y1 - 2008/8/18

N2 - Treatment of trans-(Et2O)(2)MoCl4 with 2 or 3 equiv of Na(silox) (i.e., (NaOSiBu3)-Bu-t) afforded (Silox)(3)MoCl2 (1-Mo) or (silox)(3)MoCl (2-Mo). Purification of 2-Mo was accomplished via addition of PMe3 to precipitate (Silox)(3)CIMoPMe3 (2-MoPMe3), followed by thermolysis to remove phosphine. Use of MoCl3(THF)(3) with various amounts of Na(silox) produced (Silox)(2)ClMoMoCl(Silox)(2) (3-Mo). Alkylation of 2-Mo with MeMgBr or EtMgBr afforded (Silox)(3)MoR (R = Me, 2-MoMe; Et, 2-MoEt). 2-MoEt was also synthesized from C2H4 and (Silox)(3)MoH, which was prepared from 2-Mo and NaBEt3H. Thermolysis of WCl6 with (HOSiBu3)-Bu-t afforded (Silox)(2)WCl4 (4-W), and sequential treatment of 4-W with Na/Hg and Na(silox) provided (Silox)(3)WCl2 (1-W, tbp, X-ray), which was alternatively prepared from trans-(Et2S)(2) WCl4 and 3 equiv of Tl(silox). Na/Hg reduction of 1-W generated (silox)(3)WCl (2-W). Alkylation of 2-W with MeMgBr produced (Silox)(3)WMe (2-WMe), which dehydrogenated to (Silox)(3)WCH (6-W) with Delta H-double dagger = 14.9(9) kcal/ mol and Delta S-double dagger = -26(2) eu. Magnetism and structural studies revealed that 2-Mo and 2-MoEt have triplet ground states (GS) and distorted trigonal monopyramid (tmp) and tmp structures, respectively. In contrast, 2-W and 2-WMe possess squashed-T-d (distorted square planar) structures, and the former has a singlet GS. Quantum mechanics/ molecular mechanics studies of the S = 0 and S = 1 states for full models of 2-Mo, 2-MoEt, 2-W and 2-WMe corroborate the experimental findings and are consistent with the greater nd(z)(2)/(n + 1)s mixing in the third-row transition-metal species being the dominant feature in determining the structural disparity between molybdenum and tungsten.

AB - Treatment of trans-(Et2O)(2)MoCl4 with 2 or 3 equiv of Na(silox) (i.e., (NaOSiBu3)-Bu-t) afforded (Silox)(3)MoCl2 (1-Mo) or (silox)(3)MoCl (2-Mo). Purification of 2-Mo was accomplished via addition of PMe3 to precipitate (Silox)(3)CIMoPMe3 (2-MoPMe3), followed by thermolysis to remove phosphine. Use of MoCl3(THF)(3) with various amounts of Na(silox) produced (Silox)(2)ClMoMoCl(Silox)(2) (3-Mo). Alkylation of 2-Mo with MeMgBr or EtMgBr afforded (Silox)(3)MoR (R = Me, 2-MoMe; Et, 2-MoEt). 2-MoEt was also synthesized from C2H4 and (Silox)(3)MoH, which was prepared from 2-Mo and NaBEt3H. Thermolysis of WCl6 with (HOSiBu3)-Bu-t afforded (Silox)(2)WCl4 (4-W), and sequential treatment of 4-W with Na/Hg and Na(silox) provided (Silox)(3)WCl2 (1-W, tbp, X-ray), which was alternatively prepared from trans-(Et2S)(2) WCl4 and 3 equiv of Tl(silox). Na/Hg reduction of 1-W generated (silox)(3)WCl (2-W). Alkylation of 2-W with MeMgBr produced (Silox)(3)WMe (2-WMe), which dehydrogenated to (Silox)(3)WCH (6-W) with Delta H-double dagger = 14.9(9) kcal/ mol and Delta S-double dagger = -26(2) eu. Magnetism and structural studies revealed that 2-Mo and 2-MoEt have triplet ground states (GS) and distorted trigonal monopyramid (tmp) and tmp structures, respectively. In contrast, 2-W and 2-WMe possess squashed-T-d (distorted square planar) structures, and the former has a singlet GS. Quantum mechanics/ molecular mechanics studies of the S = 0 and S = 1 states for full models of 2-Mo, 2-MoEt, 2-W and 2-WMe corroborate the experimental findings and are consistent with the greater nd(z)(2)/(n + 1)s mixing in the third-row transition-metal species being the dominant feature in determining the structural disparity between molybdenum and tungsten.

KW - FORBIDDEN CHEMICAL-REACTIONS

KW - TRANSITION-METAL-COMPLEXES

KW - OPEN-SHELL ORGANOMETALLICS

KW - ELECTRONIC-STRUCTURE

KW - BIS(DITHIOLENE) COMPLEXES

KW - REACTION SYSTEMS

KW - ALKYL COMPLEXES

KW - BOND ACTIVATION

KW - ATOM-TRANSFER

KW - C-H

UR - http://www.scopus.com/inward/record.url?scp=50449103393&partnerID=8YFLogxK

U2 - 10.1021/ic800139c

DO - 10.1021/ic800139c

M3 - Article

SN - 0020-1669

VL - 47

SP - 7139

EP - 7153

JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 16

ER -

Molybdenum and tungsten structural differences are dependent on nd(Z)(2)/(n+1)s mixing: Comparisons of (silox)(3)MX/R (M = Mo, W; silox = (Bu3SiO)-Bu-t)

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Keywords

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