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Experimental evidence that the dinuclear complex Me 2 Si[η 5 -C 5 H 4 Fe(CO) 2 -(η 1 -CH 2 C 6 H 5 )] 2 shows enhanced reactivity over its mononuclear analogy η 5 -C 5 H 5 Fe(CO) 2 (η 1 -CH 2 C 6 H 5 in photogragmentation to produce bibenzyl and FeFe bonded product is presented. Information from a series of competition and crossover experiments indicate that two factors are involved in the enhancement: (1) the ability to photochemically produce a 16-electron unsaturated benzyl unit in close proximity to a saturated partner, and (2) the inability of the FeFe bonded species 4 to quench free benzyl radicals in solution. Chemical reaction of Me 2 Si[η 5 -C 5 H 4 Fe(CO) 2 (η 1 -CH 2 C 6 H 5 )] 2 with Me 3 NO produces bibenzyl and establishes that loss of CO is the initial step in the fragmentation reaction. In addition, trapping experiments with 9,10-dihydroanthracene show that bibenzyl is formed from free benzyl radical; BBased on these results an overall mechanism is proposed.

Benzylideneacetoneiron tricarbonyl (BDAFe(CO) 3 ) reacts with acyclic conjugated dienes to give good to moderate yields of dieneiron tricarbonyl complexes. Competition experiments demonstrate that there is a large difference in relative reactivities among a series of acyclic and cyclic dienes. Certain cyclic and nonconjugated dienes are essentially inert. These differences are rationalized primarily on the basis of the conformation of the diene. Results of the reaction of cycloheptatriene with BDAFe(CO) 3 /BDA mixtures support a mechanism of BDAFe(CO) 3 selectivity previously postulated.

A new metal-metal bonded binuclear iron system [Me 2 SiCH 2 CH 2 SiMe 2 ][η 5 -C 5 H 4 Fe(CO) 2 ] 2 ( 2 ) has been prepared by treating two equivalents of NaCp with one equivalent of ClSi(Me) 2 CH 2 CH 2 SiClMe 2 obtaining the intermediate (C 5 H 5 )Si(Me) 2 CH 2 CH 2 Si(Me) 2 (C 5 H 5 ) which then is directly allowed to react with Fe(CO) 5 given 2 in 30% yield. From this cyclopentadienyldisilyl linked system three new binuclear irom complexes are formed. Treatment of 2 with Na/Hg in THF produced the dianion [Me 2 SiCH 2 CH 2 SiMe 2 ][η 5 -C 5 H 4 Fe(CO) 2 − ] 2 which is quenched with CH 3 I giving [Me 2 SiCH 2 CH 2 SiMe 2 ][η 5 -C 4 H 4 Fe(CO) 2 CH 3 ] 2 ( 4 ) in 76% yield. Complex 2 is oxidized with 1.2 equivalent of I 2 to give [Me 2 SiCH 2 CH 2 SiMe 2 ][η 5 -C 5 H 4 Fe(CO) 2 I] 2 ( 5 ) in 85% yield. Photolysis of 5 (1 equiv.) and PPh 3 (3 equiv.) results in the formation of the bis-substituted compound [Me 2 SiCH 2 CH 2 SiMe 2 ][η 5 -C 5 H 4 Fe(CO)(PPh 3 )I] 2 ( 6 ). These four new binuclear iron complexes are characterized by 1 H, 13 C, and 31 P NMR and IR spectroscopy.

The amine substituted phosphines (C 6 H 5 ) 2 PN(H)CH 2 CH 3 and (C 6 H 5 ) 2 PN(H)CH 2 C 6 H 5 react with C 5 H 5 Fe(CO) 2 CH(C 6 H 5 ) (OCH 3 ) photolytically to give moderate yields of the four-membered chelate ring complexes C 5 H 5 Fe (CO) [(C 6 H 5 ) 2 PN (CH 2 CH 3 ) C H (C 6 H 5 )] and C 5 H 5 Fe (CO) [(C 6 H 5 ) 2 PN (CH 2 C 6 H 5 )C H(C 6 H 5 )], respectively. Photolysis of C 5 H 5 Fe(CO) 2 CH(C 6 H 5 ) (OCH 3 ) in the presence of (S)-(−)-diphenyl(1-phenylethylamino)phosphine leads to the isolation of C 5 H 5 Fe(CO)[(C 6 H 5 )2PNC(CH 3 ) (C 6 H 5 )]CH 2 C 6 H 5 which is proposed to arise from a formally 1,3-hydrogen shift rearrangement of an intermediate four-membered chelate ring complex.

The compounds (η 5 -C 5 R 5 ) 2 Fe 2 (CO) 2 (μ-CO)(μ-CH 2 ) (R = H, CH 3 ) have been prepared through the reaction of chloromethyl pivalate with the appropriate metal anions, η 5 -C 5 H 5 Fe(CO) 2 K and η 5 -C 5 Me 5 Fe(CO) 2 K.

Photolysis of Me 2 Si[C 5 H 4 Fe(CO) 2 ] 2 [1] in the presence of bis-phosphine ligands (dppe and dppm) gives good yields of doubly linked diiron complexes. In the reaction with dppe, a mechanically linked tetranuclear species can also be isolated.