The synthesis and X-ray structures of η¹-, η³-, and η⁵-dienolate complexes of manganese carbonyl

Abstract

, and -q5-ester dienolate complexes of Mn(CO),, have been prepared and the crystal structures of the phenyl ester member have been obtained for all three bonding modes. The allyl (anti--q3) member shows some bonding distortions compared to a simple allyl ligand. The structure of the r15-1-oxapentadienyl ligand complex is substantially different from a rhenium analog in that the organic ligand is non-planar with significantly different bond distances. The r15-complex reacts rapidly with triphenylphosphine to generate the syn--q3-complex.Key

Fluoroalkyl Radical Generation by Homolytic Bond Dissociation in Pentacarbonylmanganese Derivatives

“…In the ordered structure of complex 5 , which has three α‐F substituents, the Mn−CF 3 distance (2.067(3) Å) is ≈0.1 Å shorter than the Mn−CH 2 CF 3 distance in compound 7 (2.162(2) Å). For comparison, other distances to the sp 3 ‐hybridized C atoms without any F substituents are 2.214(3) Å in [(CO) 5 Mn(CH 2 CH=CHCOOPh)] and 2.195(6) and 2.196(8) Å in [(CO) 5 Mn(CH 2 CH 2 ‐ o ‐C 6 H 4 −CH 2 CH 2 )Mn(CO) 5 ], whereas positional disorder in the simpler reference compound [(CO) 5 Mn(CH 3 )] prevented an accurate determination of the Mn−CH 3 distance . The distance in [(CO) 5 Mn(CH 2 Cl)], which has one α‐Cl substituent, is 2.125(10) Å .…”

Adventitious formation of a new oxopentadienyl Mn(I) tricarbonyl complex: Structural study and bonding investigation of (η5-CH2C(Fc)CHC(Fc)O)Mn(CO)3

“…The 1 H NMR spectrum of 3 displayed all expected signals with the 2 typical broad multiplets of the ferrocenyl's cyclopentadienyl entities at 4.31 and 4.19 ppm. The 13 C NMR spectrum of 3 at 263 K displayed also all the expected signals. The chemical shifts of the three carbonyl ligands coordi- The ORTEP-type diagram of 3 shown in Fig.…”

“…Noteworthy, such one-pot aldol condensation was already observed for acetylferrocene by Bruce [10] using MeMn(CO) 5 as well as by Woodgate [11] for [h 6 -(phenyl)-ethanone]Cr(CO) 3 6 using (h 1 -benzyl)Mn(CO) 5 . Moreover, Wu [12] and Sorensen [13] reported separately the preparation of the 1,3-diferrocenyl-buten-1-one ligand 7 through aldol condensation under conventional conditions. The case reported by Bruce [10] resembles the one dealt with herein: in the formation of 3 the putative "aldol" condensation of 1 should result formally only in the loss of water and the formation of toluene, the presence of which was practically not sought (Scheme 1).…”

“…complex 6, two p-bonded Cr(CO) 3 fragments are oriented trans to each other (Chart 1, Table 1). Table 1 shows related examples of h 5 or h 3 -tricarbonylmanganese complexes 8 [13], 9 [14] and 10 [15] which can be compared with complex 3 and the ligand 1,3-diferrocenyl-buten-1-one 7 [16].…”

“…The13 C NMR signal at 168.8 ppm was assigned to the oxygen-bearing carbon atom of the oxopentadienyl ligand (see experimental part for details).Scheme 1. Synthetic scheme leading to complex 3.…”