Photochemistry studies of matrix isolated carbonyl iron silyl complexes by FT-IR spectroscopy

Silylene-Bridged Dinuclear Iron Complexes [Cp(OC)2Fe]2SiX2 (X = H, F, Cl, Br, I). Synthesis, Molecular Structure, Vibrational Spectroscopy, and Theoretical Studies

“…In the Raman spectrum of 1 , the bands at 2074 and 2043 cm -1 were assigned to symmetrical SiH stretching modes. For the other peaks at 2028, 1987, 1978, and 1928 cm -1 , the theoretical calculations and literature indicate CO stretching modes strongly mixed with symmetrical and asymmetrical SiH 2 stretching vibrations. , For 2 − 4 , these vibrations are “pure” CO stretchings and no other internal coordinates are involved. − As expected, the DFT calculations, which were performed without any symmetry restriction, led to more than two ν(CO) modes in each case ( 1 − 5 ) (Table ). Taking into account that the X-ray structure determination indicated a C 2 symmetry for all complexes, we believe that the appearance of more than two bands in the CO spectral region of 2 (1999, 1983, 1956, 1944, and 1931 cm -1 ) is mostly due to the existence of different conformers, as previously reported for similar compounds …”

“…For the other peaks at 2028, 1987, 1978, and 1928 cm -1 , the theoretical calculations and literature indicate CO stretching modes strongly mixed with symmetrical and asymmetrical SiH 2 stretching vibrations. 32,33 For 2-4, these vibrations are "pure" CO stretchings and no other internal coordinates are involved. [32][33][34][35][36][37] As expected, the DFT calculations, which were performed without any symmetry restriction, led to more than two ν(CO) modes in each case (1-5) (Table 3).…”

“…32,33 For 2-4, these vibrations are "pure" CO stretchings and no other internal coordinates are involved. [32][33][34][35][36][37] As expected, the DFT calculations, which were performed without any symmetry restriction, led to more than two ν(CO) modes in each case (1-5) (Table 3). Taking into account that the X-ray structure determination indicated a ) for [Cp(CO)2Fe]2SiX2 with X ) H (1), F (2), Cl (3), Br (4), and I (5), Together with Their Tentative Wavenumbers are given in units of cm -1 .…”

2 Matrix isolation

“…The carbonyl iron silyl complexes of the type Cp(CO) 2 Fe-SiH 2 R (R = H or Me) have been photolysed in krypton matrices. 87 Matrix isolation and flash photolysis in room-temperature solution have been used to monitor the photochemistry of the complexes Ru(CO) 3 (dmpe) (dmpe = Me 2 PCH 2 CH 2 PMe 2 ) 88 and of cis-Ru(dmpm) 2 H 2 (dmpm = Me 2 PCH 2 PMe 2 ). 89 The carbonyl complex gives Ru(CO) 2 (dmpe)•S (S = matrix host) upon UV photolysis.…”