ISSN:
1572-8862
Schlagwort(e):
Alkoxide
;
tungsten
;
cluster
;
carbide
;
hydride
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Maschinenbau
,
Physik
Notizen:
Abstract A minor product in the reaction between W2(NMe2)6 and neopentanol in hydrocarbon solvents has been isolated and characterized by elemental analysis,1H and13C NMR spectroscopy and a single crystal X-ray study. At −174°C,a=11.669(1) Å,b=25.801(5) Å,c=24.345(4) Å, β=100.91(1)°,Z=4,d calcd=1.60 g cm−3, and space group P21/c. The compound is formulated as W4(μ4-C)(NMe)(OCH2Bu t )11 (H). There is a W4-butterfly and the carbido group is cradled between the wing-tip and back-bone W atoms with W-C=1.90–1.96 and 2.20–2.26 Å, respectively. The five W-W bonding distances span a narrow range 2.74–2.84 Å. The structure of this molecule resembles that previously reported for W4(μ4-C)(NMe)(OPr i )12 where one OPr i ligand bonded to a backbone W atom is replaced by a hydride ligand. The hydride was not located crystallographically but is implicated by (i)a void at one W atom, (ii) itstrans-influence as determined by the W-O bond distance of the group trans to the void, and (iii) electron counting which requires the presence of a W4(μ4-C)14+ rather than a W4(μ4-C)13+ moiety in order to account for the observed diamagnetism. The present finding is compared with the previous preparations and characterizations of W4(μ4-C)14+ alkoxide supported clusters.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00702712
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