Solid state structure of the tantalum bis-aryl compounds Ta(OAr-2,6R2)3(C6H5)2 (R = CH3, Pri; OAr-2,6R2 = 2,6-dialkylphenoxide): Observation of a lack of correlation of MOAr distances and MOAr angles for aryloxide derivatives of niobium(V) and tantalum(V)

Autor: Phillip E. Fanwick, Bryan D. Steffey, Ian P. Rothwell
Rok vydání: 1990
Předmět:
Zdroj: Polyhedron. 9:963-968
ISSN: 0277-5387
DOI: 10.1016/s0277-5387(00)84298-9
Popis: Treatment of the tantalum dichloride compounds Ta(OAr-2,6Me2)3Cl2 or Ta(OAr-2,6Pr2i)3Cl2 (OAr-2,6Me2 = 2,6-dimethylphenoxide; OAr-2,6Pr2i = 2,6-diisopropylphenoxide) with phenyl lithium (2 equiv) leads to the formation of the bis-phenyl compounds Ta(OAr-2,6Me2)3(C6H5)2 (1) and Ta(OAr-2,6Pr2i)3(C6H5)2 (2), respectively, in moderate yields. Single crystal X-ray diffraction analyses of both 1 and 2 show them to be isostructural. In both compounds a trigonal bipyramidal environment about the metal centre is evident with trans, axial aryloxide oxygen atoms. Short TaO distances in the range of 1.848(5)-1.881(3) A and almost linear TaOAr angles are present. The central coordination environments in 1 and 2 are strikingly similar to those found for the biscyclometallated compound Ta(OC6H3Ph-C6H4)2(OAr-2,6Ph2). Combining the structural data for 1 and 2 with those of other alkyl, aryloxide compounds of niobium(V) and tantalum(V) shows that the MOAr distances span a narrow range of 1.85-1.95 A, while the corresponding MOOAr angles vary from 135 to 180° with no correlation between the two parameters. Crystal data for TaO3C36H37 (1) at 19°C: a = 19.313(3), b = 11.652(1), c = 15.288(1) A, β = 113.13(1)°, Z = 4, dcalc = 1.446 g cm−3 in space C2/c; for TaO3C48H61 (2) at 21°C: a = 11.955(2), b = 19.585(2), c = 19.337(2) A, β = 103.742(9)°, Z = 4, dcalc = 1.309 g cm−3 in space group P21/n.
Databáze: OpenAIRE
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