ic991426l_si_001.cif (71.66 kB)
Ligand Substitution Reactions of W6S8L6 with Tricyclohexylphosphine (L = 4-tert-Butylpyridine or n-Butylamine): 31P NMR and Structural Studies of W6S8(PCy3)n(4-tert-butylpyridine)6-n (0 < n ≤ 6) Complexes
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posted on 2000-06-07, 00:00 authored by Song Jin, D. Venkataraman, Francis J. DiSalvoThe substitution reactions by bulky tricyclohexylphosphine (PCy3) ligands on W6S8L6 (L = 4-tert-butylpyridine
or n-butylamine) clusters were investigated to prepare clusters with mixed axial ligands for low-dimensional
cluster linking. When 4−6 equiv of PCy3 are used to react with W6S8(4-tert-butylpyridine)6 (4) in THF, cis-W6S8(PCy3)4(4-tert-butylpyridine)2 (1) is preferentially formed. But when starting with W6S8(n-butylamine)6 (2),
only W6S8(PCy3)6 (3) is produced with 6 equiv of PCy3. Other conditions with fewer equivalents of PCy3 led to
mixtures of partially substituted complexes in the W6S8L6-n(PCy3)n (0 ≤ n ≤ 6, L = 4-tert-butylpyridine or
n-butylamine) series. A significantly distorted structure for 1 helps to explain its preferential formation. 1H NMR
spectra were collected for clusters 1 and 2 and 31P NMR spectra for 1 and W6S8(4-tert-butylpyridine)6-n(PCy3)n
complexes. P−P coupling through P−W−W−P is reported for the first time in octahedral metal clusters and
shown to be very useful in identifying nearly all the W6S8L6-n(PR3)n complexes and their stereoisomers in the
mixtures even before individual species are isolated.