Mono-phenoxy oxo complexes of tungsten(VI) (original) (raw)
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Synthesis and Structural Characterization of ‘Non-VSEPR’ Structures of Oxo-Tungsten Complex
E-Journal of Chemistry, 2011
The crystal structure of [(CH3)4N]4[WOCl4F][WO3Cl4] was determined by single crystal x-ray diffraction technique. The crystal is monoclinic, space group C 2/m, with a= 28.23(10) Å, b= 11.60(4) Å,c= 13.48(5) Å, β=118.43(7)°, V= 3886(2)Å3, Z=4. The structure was solved by direct methods and refined by least-squares methods to a final R = 0.0512 for 3825 observed reflections with I>2σ(I). In crystal there are two crystallographic distinct anions, both with cis geometry; the O-W-F and O-W-O angles are 97.5(3)° and 103.1(3) ° respectively. All structures are cis configurations that confirm a preference for angles below 90° and 180° between cis and trans σ-donor ligands, respectively.
Polyhedron, 1987
Reaction of [w(NPh)Cl& with various quantities of ethanol and t-butylamine leads to [W(NPh)&-OEt)(OEt),],, w(NPh)(p-OEt)(OEt),Cl] and [w(NPh)(O-Et)Cl,(NH,CMe,)]. A 1: 1 proportionation reaction of [W(NPh)Cl& and [w(NPh)& 0Et)(OEt)3] gives [W(NPh)(p-OEt)(OEt)Cl&, whereas a 3 : 1 proportionation gives [W(NPh)b-OEt)Cl,],. Bridge-splitting reactions of [W(NPh)@-OEt)Cl,],, with PMe, or Et,NCl give ~(NPh)(OEt)Cl,(PMe,)] and [W(NPh)(OEt)Cld][Et,N]. [W(NPh)&-OEt)Cl& reacts with Ph&Cl to give [W(NPh)(OEt)Cl.,][Ph,Cj and [w(NPh)Cl& reacts with Ph,COEt to give [W(NPh)C&(OEt)][Ph,Cj. The trityl complexes do not react further to give amido complexes (W-NCPh3Ph). The products were characterized by analytical data, IR, 'H and13C NMR spectroscopy. The crystal and molecular structure of [W(NPh)@-OEt)(OEt),Cl], was determined from single-crystal X-ray diffractometer data. The crystals are triclinic with a = 9.637(2) & b = 11.135(l) A, c = 8.016(l) & a = 108.47(l)", B = 105.51(l)", y = 91.51(l)", and space group PT. The structure was solved by Patterson and Fourier methods and refined to R = 0.039 for the 1450 observed data. The molecule is a dimer with the two halves centrosymmetrically related. Both W atoms adopt a distorted octahedral coordination geometry and are linked by two ethoxo bridges. Tram to the bridging donors is a linear phenylimido group with a W-N bond length of 1.759(9) A and a W-N-C bond angle of 172.4(9)". The remaining octahedral sites are filled by a chloro ligand and two c&orientated alkoxide ligands where the W-O bond distances of 1.835(9) and 1.865(7) A indicate both ligands participate in z-bonding to the metal.
New types of organometallic oxo complexes containing tungsten
Organometallics, 1985
Finally, it should be noted that the $=diene-carbonyl complex (20) requires somewhat more forcing conditions for its preparation than do the related phosphine compounds (18 and 19). Thus, when L = CO in' reaction 8, a hexanes solution of the organometallic reactant must be subjected to 60 psig of carbon monoxide at room temperature for 5 days in order to effect complete conversion. This observation again gives a clear indication of the relatively high inertness of the Mo-~~-trans-diene linkage in 8 to undergo substitution reactions. Even more surprising is the fact that no CpMo(NO)(CO),, the disubstituted product, is formed during this transformation.
Characterization of new tungsten(VI) amide complexes
Inorganic Chemistry, 1993
Several examples of W(V1) imide derivatives have been synthesized and studied for their role in the metathesis and polymerization of olefins and for their reactivity in competitive 7r bonding situations.'-ll In contrast the syntheses of W(V1) amide complexes and their reactivities are less well developed. 2-17 Examples of tungsten imido and oxo complexes with amide coligands have been reported r e~e n t l y .~J~ In earlier work, Bradley and Chisholm and co-workers have reported the syntheses and characterization of the homoleptic amide complex W(NMe2)s and of some related derivatives.lf-l5 In contrast to the r e d u d dinuclear amides W2(NR2)6. for which an extensive reactivity at both the W=W bond and at the terminal ligand sites has been developed,1* viable ligand substitution reactions of the mononuclear W(V1) amide complexes were found to be quite limited.14 We report here the syntheses and characterization of new tungsten-(VI) amide-chloride complexes, and an examination of stability and reactivity relevant to the derivatization of the high-valent tungsten amide series. ResdQ d Discussion Syntheses of Tris(amide) Complexes, WCIJ(NR~)J. The reaction of WSC4 with 3 or 4 equiv of NJv-dialkyl(trimethylsily1)amine in THF at 0 OC led to the formation of a red solution, which, upon cooling, deposited a red or orange precipitate. This product was filtered and identified as WCls(NR2)3 (1 when R = Me, 2 when R = Et, and 3 when NR2 = pyrrolidine). Because
Tungsten(VI) and Tungsten(V) Fluoride Complexes
WF6 reacts with phosphines R3P forming 1:1 compounds. With R=P(CH3)3 the coordination around the tungsten atom is capped trigonal prismatic, with R=P(CH3)2C6H5 the coordination is capped octahedral, as established by single-crystal structure determinations: [(CH3)3P[BOND]WF6]: a=752.5(21), b=945.7(24), c=629.8(18) pm. β=110.36(13)°, space group Cm, Z=2; [(CH3)2(C6H5)P[BOND]WF6]: a=762.2(2), b=1123.5(2), c=2647.5(6) pm, space group Pbca, Z=8. [(CF3CH2)2N[BOND]WF5] reacts smoothly with P(C6H5)3 forming known P(C6H5)3(F)2 and [(CF3CH2)2N[BOND]WF4[BOND]P(C6H5)3], a stable, green, molecular species, identified among other methods with an crystal structure determination: a=914.9(1), b=956.0(1), c=1449.8(2) pm, α=7.642(4), β=81.648(3), γ=81.519°, space group Pequation image, Z=2.
Journal of Organometallic Chemistry, 2006
The first example of a monodentate complexation of 2-(2 0 -pyridyl)quinoxaline (pq) to a metal centre through N 4 is reported. Photochemical exchange of the THF ligand in W(CO) 5 THF by pq yields W(CO) 5 (N 4 -pq) (1), where the potentially bidentate pq ligand coordinates in an unusual monodentate fashion. Complex 1 is isolated as orange crystals and fully characterized on the basis of NMR, IR, UV-Vis and emission spectroscopy. The structure of 1 was determined by X-ray analysis. W(CO) 5 (N 4 -pq) (1) crystallizes in space group P2 1/n , monoclinic crystal system with a = 7.0237(5) Å , b = 10.4618(8) Å , c = 23.7768(18) Å , Z = 4 and V = 1731.9(2) Å 3 . Complex 1 exhibits intramolecular CHÁ Á ÁN and intermolecular CHÁ Á ÁO hydrogen bonds between the CH groups and nitrogen atoms of quinoxaline and CH groups and oxygen atoms of carbonyls, respectively, resulting in a supramolecular architecture in solid state. The preference to N 4 as coordination site is discussed in terms of electronic interactions. Solutions of 1 emits dually at 77 K while they are moderately instable at room temperature, as 1 undergoes chelation via a first-order kinetic process to form W(CO) 4 pq (2). The determined reaction rate of 1 in toluene is 2.3 · 10 À5 s À1 (at 298 K) and is compared with literature values for other W(CO) 5 L (L:diimine) complexes.
Organometallics, 1991
poor quality of these crystals. All data were collected with w / 2 8 scan mode. Data were corrected for Lp and for the obeerved linear decay of the reference reflections. Absorption correction was applied for 15 and 17 by using the DIFABS method;n redundant data were merged into a unique data set. The structures were solved with either standard Patterson methods (15,16), or with direct methods (14,17) (SHELXS~S)~ and subsequent difference Fourier synthew. Refinement on F was carried out by full-matrix least-squares techniques. H atoms were introduced on calculated positions (C-H = 0.98 A) and included in the refinement riding on their carried a h " All non-hydrogen atoms were refined with anisotropic thermal parameters, H atoms were refined with one common isotropic thermal parameter. Weights were introduced in the final refinement cycles. Final atomic coordinates and equivalent isotropic thermal parameters are listed in Tables 11-V. Neutral-atom scattering factors were taken from Cromer and Manna and corrected for anomalous dispersion.m All calculations (27) Walker, N.; Stuart, D. Acta Cryatallogr. A 1983,39, 158. (28) Sheldrick. G. M. SHELXS86. &?omam for crystal structure determination; Univereity of G8ttingen: G b b g e n , Federal Republic of Germany, 1986.
Supramolecular assemblies of tungsten complexes with unusual chelating groups
Polyhedron, 1998
Metal complexes of ligands with q~-O coordinated carbonyl moieties are well-known throughout the inorganic literature. However, metal complexes containing authentic acid chloride ligands have not previously been isolated. The synthesis and characterization of compounds with the formula W(X)C13(OPh-2-COCI) (2) [X = O (2a), NC6H3-2,6-(CH3)2 (2b), and Ph2C2 (2e)] are reported. The crystal structures of 2a and 2e were solved, showing the interaction of the acid chloride carbonyl moiety with the tungsten center. Complex 2e adopts a channelled structure having six-fold symmetric voids in the solid state. As was anticipated, the coordinated acid chloride of 2a reacts readily with nucleophiles to produce the ester WOC13(OPh-2-COPr n) (3) and the amide WOC13(OPh-2-CONHBu') (4a). A related amide complex WOCI~(OPh-2-CONH2) (4b), synthesized by the reaction of WOCI4 with salicylamide, displays an infinite-chain structure supported by hydrogen bonding between the amide group and the oxo ligand of an adjacent tungsten complex. The ,l~-O coordinated nitro compounds W(X)C13(OPh-2-NO2) (5) [X = O (5a), NC6H3-2,6-(CH3)2 (5b), and Ph2C2 (5e)] have also been isolated and the crystal structure of 5e is reported, ct2~