Vibrational spectroscopic and force field studies of (η5-Cp)ML3-type complexes (M=Mn, Re; L=CO, O)

1,3,5‐Triamino‐1,3,5‐trideoxy‐cis‐inositol, a Ligand with a Remarkable Versatility for Metal Ions. Part XIII

“…Moreover, the observation of well-resolved bands is indicative of characteristic differences between the two type of donor groups in terms of s-and p-bonding properties (vide infra). Similarly, the trioxo complex 2 exhibited three strong and well-resolved bands at 934, 914, and 894 cm À1 , indicative of ReO stretching vibrations [20]. For both compounds, the observed positions of these bands are very similar to those reported for related [Re(CO) 3 ] and…”

“…Some information on the structural properties could be derived from IR spectroscopy. Binding of the fac-[Re(CO) 3 ] unit by the three O-or N-donors of taci (type (i) or type (iv)) would result in a C 3v structure for 1, and two characteristic CO stretching vibrations (symmetry species A and E) would be V complexes with extended taci-type ligands as reported in [14] and [15] expected around 1850 ± 2050 cm À1 [19] [20]. For an asymmetric coordination mode such as type (ii) or type (iii), the symmetry of the complex is lowered to C s , the degeneracy of the E-mode is lost, and, consequently, a total of three CO stretching vibrations should be observed.…”

Synthesis of Cyclopentadienyl-Based Trioxo-rhenium Complexes and Their Use as Deoxydehydration Catalysts

“…All 1 H NMR signals, particularly the distinct Cp−H resonances, are shifted to a low field region compared to the signals in the corresponding Cp′Re(CO) 3 39 The (Re−O) asym band of the less-substituted 2b (882 cm −1 ) and 3b (884 cm −1 ) are found at slightly higher energy than that of 1b (877 cm −1 ); this band for these three complexes appear at higher energy than that for the per-alkylated complexes 4b−6b (869−875 cm −1 ) ( Table 1). This suggests that the ReO multiple bond is weakened by strongly donating Cp-ligands.…”

Catalysis and Organometallic Chemistry of Monometallic Species

“…154 A similar conclusion to that of a related study 119 showed that the original interpretation of the X-ray data gave too disparate internal and terminal C-C bonds lengths. Photon electron spectroscopy and DFT calculations have been used to compare the electronic structures of alkyl and hydride complexes of the moiety {Re(η 5 -C 5 H 5 )(NO)(L)} that show that the methyl group may be acting as a weak π-donor 155 156 Time resolved IR and flash photolysis have been used to investigate reactive intermediates relevant to the carbonylation of MeMn(CO) 5 and determine activation parameters. 157 Relevant to Fischer-Tropsch an unusual reaction between [Mn(CO) 5 -(Si(p-Tol) 2 H)] (Tol = tolyl) and hydride transfer agents leads to reduction of the carbonyl ligands followed by Si-C and C-C bond formation to give MeSi(p-Tol) 2 OH and EtSi(p-Tol) 2 OH.…”