Photoinduced oxidative addition of a distal aromatic carbon-hydrogen bond of a benzyl group. Isolation and characterization of [cyclic]-(.eta.5-C5R4CH2C6H4)Fe(CO)2 from irradiation of (.eta.5-C5R4CH2C6H5)Fe(CO)2Me

The Effects of Ancillary Ligands on Metal–Carbon Bond Strengths as Determined by C–H Activation

“…366 nm irradiation of the yellow complex 1 led to the colorless phenyl hydride product in good yield. The quantum yield was determined to be 1.0 AE 0.3, which is higher than for many other organometallic photoprecursors [2][3][4][5][6] …”

“…The true mechanism, however, is one in which the benzene is displaced. If neopentyl isocyanide is added to 2, a bimolecular reaction occurs to generate Tp 0 Rh(CNR) 2 . The rate is first order in [CNR] at low isocyanide concentrations but zero order in [CNR] at high isocyanide concentrations, which is consistent with a pre-equilibrium between 2 and the η 2 complex (κ 2 -Tp 0 )Rh(η 2 -C 6 H 6 )(CNR) followed by associative substitution of the benzene at a square planar coordinatively unsaturated intermediate (Eq.…”

“…In both of the latter cases, the sp 3 C-H activation products are unstable and convert to the terminal alkynyl products at room temperature after a few days (Scheme 1). Similarly, the activation of arylalkynes leads to mixtures of sp and sp 2 by irradiation of 1 or by reductive elimination of methane from 3 in the presence of the alkyne [13]. The fragment [Tp 0 Rh(CNR)], prepared from irradiation of 1 or reductive elimination of methane from 3, was found to react with a wide variety of substituted methanes.…”

New chemical and stereochemical applications of organoiron complexes

“…Other reported reactions involve the photoinduced, oxidative addition of an aromatic C–H bond of a distal benzyl group to the Fe center [ 522 ], and photoinduced conversion of the (η 5 -C 5 H 5 )Fe(CO) 2 (η 1 -C 5 H 5 ) complex into the ferrocene derivative [ 523 ]; also the photochemistry of some (η 4 -cyclopentadiene)Fe(CO) 3 complexes [ 524 ], and photochemical insertion of alkynes into the PR bridged clusters, e.g., (η 3 -PR)Fe 3 (CO) 10 [ 525 ] and (η 4 -PR) 2 Fe 4 (CO) 11 [ 526 ] have been reported. The low temperature studies also include photochemical reaction of alkenes with Fe(CO) 5 [ 527 ], photochemical reaction of Fe(CO) 2 (NO) 2 with 1,3-butadienes [ 528 ]; also, photochemistry of [Fe 2 (CO) 7 L](L=2,2′-bipyridine, 1,10′-phenanthroline), causing substitution of CO by nucleophiles [ 529 ], and photochemical rearrangement of (η 2 -C 5 Me 5 )Fe(CO) 2 CH 2 SiMe 2 H into (η 5 -C 5 Me 5 )Fe(CO) 2 SiMe 3 [ 530 , 531 ].…”

“…The stereodirection of the phosphine ligand (PPh 3 ) in triphenylphosphine-substituted organoiron complexes has been recognized [ 60 , 64 , 192 , 209 , 286 – 289 , 293 ] and importance of the phosphorus atoms in transition metal complexes including organoiron complexes is of current interest [ 36 , 41 , 471 , 531 , 533 – 535 ]. A series of new iron complexes of phosphinine [ 537 , 538 ], phosphine [ 539 – 542 ] and phosphane [ 522 , 543 , 544 ] derivatives have been prepared and their reactions studied.…”