Tein-Fu Wang

Half-sandwich complexes with intramolecular amino group coordination: synthesis and structure of cationic molybdenum dienyl complexes

A half-sandwich cationic molybdenum dienyl complex with intramolecular amino group coordination was obtained from η5-C5H4CH2CH2N(CH3)2Mo(CO)2(η3-C6H9) via hydride abstraction followed by CO extrusion. It crystallized as an orange monoclinic compound with a = 10.4867(14), b = 14.843(3), c = 11.882(3) A, β = 94.057(15)°. The cyclohexadienyl ligand is shown as boat conformation. A second bidentate complex was isolated. Spectroscopic and elemental analysis data support the demethylation product of [η5-C5H4CH2CH2NH(CH3)Mo(CO)( η3-C6H8)]+ PF6−.

Synthesis of a novel bidentate complex of η5-C5H4CH2CH(CH3N(CH3)(C3H5)Mn(CO)2

Abstract Irradiation of the half-sandwich manganese tricarbonyl complex η 5 -C 5 H 4 CH 2 CH(CH 3 )NH(CH 3 )Mn(CO) 3 m, which itself contained a secondary amine branch on the cyclopendatidenyl group, to give bidentate complex, η 5 -C 5 H 4 CH 2 (CH 3 ) NHCH 3 M n(CO) 2 . Deprotonation followed by allylation gave N -allylation compound, η 5 -C 5 H 4 CH 2 CH(CH 3 ) N(CH 3 )(C 3 H 5 )M n(CO) 2 , which was unequivocally identified by spectroscopic and X-ray diffraction studies.

Preparations of novel half-sandwich iron carbonyl phosphine complexes: Intramolecular link between the cyclopentadienyl and the phosphine ligand

Abstract The novel iron half-sandwich complex ( η 5 : η 1 0C 5 H 4 CH 2 PPh 2 )Fe(CO)Cl ( 4 ), in which the ligating phosphine was connected to the cyclopentadienyl ring, was prepared by reacting the LiC 5 H 4 CH 2 CH 2 PPh 2 ( 2 ) with FeCl 2 followed by CO bubbling. Reaction of 4 with sp-, sp 2 - and sp 3 -hybridized carbon nucleophiles provided formal substitution product ( η 5 : η 1 -C 5 H 4 CH 2 CH 2 PPh 2 )Fe(CO)R ( 5 ). Solid state structures of the methyl complex 5a , phenylacetylide 5g and trimethylsilylacetylide 5j were characterized by single-crystal X-ray analyses.

Photoexcitation of iron-allyl complexes (η5: η1-C5H4CH2CH2PPh2Fe(CO)(η1-CH2CR=CH2) (R = H, CH3) which contains a tethered phosphine ligand

Abstract Photoexcitation of the phosphino ligand chelated iron-allyl complexes ( η 5 : η ′-C 5 H 4 CH 2 CH 2 PPh 2 )Fe(CO)( η ′-CH 2 CR=CH 2 ) ( 1a : R = H; 1b : R = CH 3 ) gives a mixture of Fe−CO bond cleavaged compound ( η 5 : η 1 -C 5 H 4 CH 2 CH 2 PPh 2 )Fe( η 3 -CH 2 CRCH 2 ) ( 2 ) and Fe-allyl bond homolysis compounds [ η 4 : η 1 -(1-CH 2 CR−CH 2 )C 5 H 4 CH 2 CH 2 PPh 2 ]Fe(CO) 2 ( 3 ) and [ η 4 : η 1 -(3-CH 2 CR−CH 2 )C 5 H 4 CH 2 CH 2 PPh 2 ]Fe(CO) 2 ( 4 ) in a ratio of 20:5:1. Their structures were determined spectroscopically. No phosphine exchange products were observed when the reaction was conducted in the presence of triphenylphosphine.

Preparation and reactions of half-sandwich rhenium nitrosyl complexes containing a tethered amino ligand

Abstract The aminorhenium nitrosyl complex [ η 5 : η 1 -C 5 H 4 CH 2 CH 2 N(CH 3 ) 2 Re(NO)(CO)] + BF 4 − ( 5a ), in which the ligating amino group was connected to the cyclopentadienyl ring, was prepared by reacting the η 5 -C 5 H 4 CH 2 CH 2 N(CH 3 ) 2 Re(NO)(CO)Br ( 4 ) with AgBF 4 . Reaction of 5a with alkylmetal reagents provided the acyl complex η 5 : η 1 -C 5 H 4 CH 2 CH 2 N(CH 3 ) 2 Re(NO)COR ( 8 ) (R  n-butyl, methyl, ethyl, isopropyl, benzyl). Solid state structures of 5b (X −  BPh 4 − ) and the acetyl complex 8b were characterized by single-crystal X-ray analyses.

Carbonyl ligand substitution of an aminerhenium benzyl complex. Interconversion of η1- and η3-benzyl complexes

Removal of a CO ligand from the η1-benzyl complex [Re(CO)2(η1-CH2Ph){NH(Me)CH2CH2(η5-C5H4)}]+Br– yielded an η3-benzyl complex. The η3 co-ordination mode was converted into η1 when the compound was dissolved in acetonitrile. Evaporation of acetonitrile removed the labile acetonitrile ligand and regenerated the η3-benzyl complex. The η3-benzyl complex [Re(CO)(η3-CH2Ph){NH(Me)CH2CH2(η5-C5H5)}]+BF4– is stable to air and moisture. The corresponding perrhenate salt has been characterized crystallographically. The tetrafluoroborate reacted with bromide, chloride and acetate anion to give the corresponding neutral η1-benzyl complexes in excellent yield. When treated with two-electron donor ligands, such as tert-butyl isocyanide and pyridine, it was converted into the corresponding (η1-benzyl)(isocyanide) and pyridine complexes.