“…Additionally, the molecule has a crystallographic inversion center and the conformation of the Cp′ ligands corresponds to that of the meso diastereomer (Figure 2). A similar conformation has been found in the related compound [Cp′ 4 Zr 2 (μ‐Te) 2 ] 10. From the distances (>3.6 Å) one can exclude direct bonding interactions between opposite atoms of the core.…”
Reaction of [Cp′2NbTe2H] (1) (Cp′ = η5‐tBuC5H4) with [W(CO)6] in decane at 140 °C gives red [{(Cp′2Nb)2WTe4}⋅W(CO)4] (2), whereas in the reaction of 1 with [Cr(CO)6] green‐black [Cp′4Nb2Te2] (3) is formed. The crystal structures of 2 and 3 have been determined. The structure of 2 contains a slightly distorted WTe4 tetrahedron to which two niobocene fragments and one W(CO)4 group are coordinated. The crystal structure determination of 3 reveals the presence of two Cp′2Nb units bridged by two Te atoms. Complex 2 represents the first example of an organometallic derivative of the unknown WTe42− anion.
“…Additionally, the molecule has a crystallographic inversion center and the conformation of the Cp′ ligands corresponds to that of the meso diastereomer (Figure 2). A similar conformation has been found in the related compound [Cp′ 4 Zr 2 (μ‐Te) 2 ] 10. From the distances (>3.6 Å) one can exclude direct bonding interactions between opposite atoms of the core.…”
Reaction of [Cp′2NbTe2H] (1) (Cp′ = η5‐tBuC5H4) with [W(CO)6] in decane at 140 °C gives red [{(Cp′2Nb)2WTe4}⋅W(CO)4] (2), whereas in the reaction of 1 with [Cr(CO)6] green‐black [Cp′4Nb2Te2] (3) is formed. The crystal structures of 2 and 3 have been determined. The structure of 2 contains a slightly distorted WTe4 tetrahedron to which two niobocene fragments and one W(CO)4 group are coordinated. The crystal structure determination of 3 reveals the presence of two Cp′2Nb units bridged by two Te atoms. Complex 2 represents the first example of an organometallic derivative of the unknown WTe42− anion.
“…The isopropyl groups in this conform er are arranged towards the front of the bent metallocene wedge as com pared to e.g. bis(tef7-alkyl-Cp)metallocenedihalides in which the dihedral substituent an gles tend to be close to 90: [6,7]. In addition to the different orientations of the Cp-rings about the central metal atom the isopro pyl groups at the Cp-rings are twisted slightly dif ferent in the three isomers (Table II) in accordance with the crystallographic independence of the three molecules 1 a, 1 b, and 1 c.…”
Section: Resultsmentioning
confidence: 94%
“…In contrast, bulky rm -alkyl substituents at the Cp-rings favour the bislateral:anti orientation. Almost ideal B-type exam ples are bis(/m -butylcyclopentadienyl)zirconiumdichloride and many derivatives thereof [6]. Bis [( 1 '-methylcyclohexyl)cyclopentadienyl]ZrCl2 is another good example [7].…”
“…Disorder involving the bridging selenides (see below) precludes any meaningful discussion on the bond lengths and bond angles of the Zr 2 Se 2 core. The core in Cp 2 Ti(μ-Se) 2 TiCp(Cl) is butterflied a total of 14.6°, while those in [( t BuCp) 2 Zr(μ-E)] 2 (E = Se 48 , Te , are planar and nearly perfect squares. 4 ORTEP view of the molecular structure of {Zr[SeSi(SiMe 3 ) 3 ] 2 (μ-Se)(μ-DMPM)} 2 .…”
A combination of either salt metathesis reactions between MCl 4 (M ) Zr, Hf) and (THF) 2 LiSeSi(SiMe 3 ) 3 (THF ) tetrahydrofuran) or between TiCl 3 (THF) 3 and (THF) 2 LiESi(SiME 3 ) 3 (E ) Se, Te), or chalcogenolysis reactions between M(CH 2 Ph) 4 (M ) Zr, Hf) and HESi(SiMe 3 ) 3 (E ) Se, Te) afforded the series of compounds M[ESi-(SiMe 3 ) 3 ] 4 (M ) Ti, Zr, Hf; E ) Se, Te). The X-ray structures of M[TeSi(SiMe 3 ) 3 ] 4 (M ) Zr, Hf) and Zr[SeSi-(SiMe 3 ) 3 ] 4 have been determined and are presented for comparison. Reaction of group 4 tetrabenzyls with 3 equiv of HSeSi(SiMe 3 ) 3 gave the complexes M[SeSi(SiMe 3 ) 3 ] 3 (CH 2 Ph) (M ) Ti, Zr, Hf) in high yields. Treatment of the zirconium and hafnium homoleptic tellurolates with 2 equiv of xylyl isocyanide produced the bis-L trans adducts M[TeSi(SiMe 3 ) 3 ] 4 [CN(xylyl)] 2 (M ) Zr, Hf) in moderate yields. The related six-coordinate DMPE adducts M[TeSi(SiMe 3 ) 3 ] 4 (DMPE) (M ) Zr, Hf; DMPE ) 1,2-bis(dimethylphosphino)ethane) were similarly prepared. Reaction of the mono-DMPE complexes with a second equilvalent of DMPE led to the elimination of Te[Si-(SiMe 3 ) 3 ] 2 and the formation of the seven-coordinate bis(tellurolate), bis(DMPE), terminal tellurides M[TeSi-(SiMe 3 ) 3 ] 2 (Te)(DMPE) 2 (M ) Zr, Hf). Both of the tellurides have been structurally characterized. The homoleptic zirconium selenolate reacts with 1 equiv of DMPE, yielding a bright red material with the stoichiometry Zr[SeSi-(SiMe 3 ) 3 ] 2 (Se)(DMPE). The diphosphine DMPM (DMPM ) 1,2-bis(dimethylphosphino)methane) also reacted with M[SeSi(SiMe 3 ) 3 ] 4 (M ) Zr, Hf) to give the bis(µ-Se), A-frame dimers {M[SeSi(SiMe 3 ) 3 ] 2 (µ-Se)(µ-η 2 -DMPM)} 2 (M ) Zr, Hf) in relatively low yields (40 and 23%). The structure of the zirconium derivative has been confirmed using X-ray crystallography. Crystallographic data are as follows: Zr[SeSi(SiMe 3 ) 3 ] 4 , monoclinic, P2 1 /c, a ) 22.6944(34) Å, b ) 15.2943(55) Å, c ) 22.7758(61) Å, β ) 105.695(17)°, Z ) 4, R ) 5.29, R w ) 3.69; Hf[TeSi(SiMe 3 ) 3 ] 4 , monoclinic, P2 1 /c, a ) 22.494(5) Å, b ) 15.609(5) Å, c ) 22.742(5) Å, β ) 104.480(5)°, Z ) 4, R ) 4.48, R w ) 5.45; Hf[TeSi(SiMe 3 ) 3 ] 2 (Te)(DMPE) 2 , monoclinic, P2 1 , a ) 14.795(3) Å, b ) 14.289(3) Å, c ) 15.4212(2) Å, β ) 102.543(3)°, Z ) 2, R ) 4.78, R w ) 6.70; {Zr[SeSi(SiMe 3 ) 3 ] 2 (µ-Se)(µ-η 2 -DMPM)} 2 , monoclinic, P2 1 /n, a ) 14.7651(13) Å, b ) 18.8579(17) Å, c ) 18.6072(17) Å, β ) 111.031(1)°, Z ) 2, R ) 8.26, R w ) 8.13.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
