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Syntheses of Molybdenum and Tungsten Imido Alkylidene Complexes that Contain a Bidentate Oxo/Thiolato Ligand
Author(s) -
Tafazolian Hosein,
VenkatRamani Sudarsan,
Tsay Charlene,
Schrock Richard R.,
Müller Peter
Publication year - 2020
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.202000068
Subject(s) - chemistry , ethylene , ligand (biochemistry) , denticity , stereochemistry , molybdenum , tungsten , crystallography , molecule , benzene , medicinal chemistry , yield (engineering) , crystal structure , inorganic chemistry , organic chemistry , catalysis , biochemistry , receptor , materials science , metallurgy
3,3′,5,5′‐Tetra‐ tert ‐butyl‐2′‐sulfanyl[1,1′‐biphenyl]‐2‐ol (H 2 [ t Bu 4 OS]) was prepared in 24 % yield overall from the analogous biphenol using standard techniques. Addition of H 2 [ t Bu 4 OS] to Mo(NAr)(CHCMe 2 Ph)(2,5‐dimethylpyrrolide) 2 led to formation of Mo(NAr)(CHCMe 2 Ph)[ t Bu 4 OS], which was trapped with PMe 3 to give Mo(NAr)(CHCMe 2 Ph)[ t Bu 4 OS](PMe 3 ) ( 1 (PMe 3 )). An X‐ray crystallographic study of 1 (PMe 3 ) revealed that two structurally distinct square pyramidal molecules are present in which the alkylidene ligand occupies the apical position in each. Both 1 (PMe 3 ) A and 1 (PMe 3 ) B are disordered. Mo(NAd)(CHCMe 2 Ph)( t Bu 4 OS)(PMe 3 ) ( 2 (PMe 3 ); Ad=1‐adamantyl) and W(NAr)(CHCMe 2 Ph)( t Bu 4 OS)(PMe 3 ) ( 3 (PMe 3 )) were prepared using analogous approaches. 1 (PMe 3 ) reacts with ethylene (1 atm) in benzene within 45 minutes to give an ethylene complex Mo(NAr)( t Bu 4 OS)(C 2 H 4 ) ( 4 ) that is isolable and relatively stable toward loss of ethylene below 60 °C. An X‐ray study shows that the bond distances and angles for the ethylene ligand in 4 are like those found for bisalkoxide ethylene complexes of the same general type. Complex 1 (PMe 3 ) in the presence of one equivalent of B(C 6 F 5 ) 3 catalyzes the homocoupling of 1‐decene, allyltrimethylsilane, and allylboronic acid pinacol ester at ambient temperature. 1 (PMe 3 ), 2 (PMe 3 ), and 3 (PMe 3 ) all catalyze the ROMP of rac ‐ endo , exo ‐5,6‐dicarbomethoxynorbornene ( rac ‐DCMNBE) in the presence of B(C 6 F 5 ) 3 , but the polyDCMNBE that is formed has a random structure.