186788-33-0Relevant academic research and scientific papers
Synthesis and reactivity of bimetallic iron-rhenium silyl complexes: Crystal structures of [(OC)3{(MeO)3Si}Fe(μ-dppm) Re(CO)4] and [(OC)3Fe(μ-Br)(μ-dppm)Re(CO)3]
Knorr, Michael,Braunstein, Pierre,Tiripicchio, Antonio,Ugozzoli, Franco
, p. 105 - 116 (1996)
The dppm-bridged heterobimetallic alkoxysilyl complex [(OC)3{(MeO)3Si}Fe(μ-dppm)Re(CO)4] (2a) has been prepared by the reaction of K[Fe{Si(OMe)3}(CO)3(η1-dppm)] (K · 1) with fac-[Re(μ-Br)(CO)3(THF)]2 in THF. The Re centre prefers to coordinate an additional CO molecule rather than a lone pair from the potentially bridging Si(OMe)3 ligand. Addition of BF3 · xEt2O resulted in replacement of one methoxy group of the Si(OMe)3 ligand by fluorine to afford [(OC)3{(MeO)2FSi}Fe(μ-dppm)Re(CO)4] (3). Upon treatment of [HFe{Si(OMe)3}(CO)3(η1-dppm)] (H · 1) with fac-[Re(μ-Br)(CO)3(THF)]2 elimination of HSi(OMe)3 occurred, yielding the bromide-bridged complex [(OC)3Fe(μ-Br)(μ-dppm)Re(CO)3] (4). The reactivity of 4 towards phosphines, phosphites, isonitriles and CO has been investigated. Addition of two equivalents of PR3 to 4 opens the metal-metal bond, yielding [(OC)3(R3P)Fe(μ-dppm)ReBr(CO)3(PR3)] (5) (PR3 = P(OPh)3, PMePh2, PMe2Ph). The complexes [(OC)3(RN≡C)Fe(μ-dppm)ReBr(CO)3] (8) (R = 2,6-xylyl, tBu) containing a dative metal-metal bond were formed by addition of one equivalent of RNC to a solution of 4. This dative metal-metal bond is cleaved after addition of a second equivalent of isonitrile to afford [(OC)3(RN≡C)Fe(μ-dppm)ReBr(C≡NR)(CO)3] (9). The related complex [(OC)4Fe(μ-dppm)ReBr(CO)4] (11) was obtained by carbonylation of 4 in an autoclave. The corresponding bis(diphenylphosphino)amine-bridged derivative [(OC)4Fe(μ-dppa)ReBr(CO)4] (13) was isolated after refluxing a mixture of [Fe(CO)4(dppa-P)] (12) and [ReBr(CO)5] in toluene. The molecular structures of 2a and 4 · 0.5CH2Cl2 have been determined by X-ray diffraction methods. In the former, the Re(CO)4 and Fe(CO)3{Si(OMe)3} fragments are linked by a rather long metal-metal bond [Fe-Re 3.013(2) A] and by a bridging dppm ligand, whereas in 4 the metal-metal bond linking the Re(CO)3 and Fe(CO)3 moieties is much shorter [Fe-Re 2.866(4) A], being supported by a double bridge: a dppm and a bromine ligand.
