128550-94-7Relevant academic research and scientific papers
Isolation of chromium(0) thiols: Molecular structure of (ButSH)Cr(CO)5
Darensbourg, Marcetta Y.,Longridge, Elizabeth M.,Payne, Vilia,Reibenspies, Joseph,Riordan, Charles G.,Springs, Jerry J.,Calabrese, Joseph C.
, p. 2721 - 2726 (2008/10/08)
The synthesis and characterization of (RSH)Cr(CO)4L (L = CO, R = But, Pri, Et, Ph; L = PEt3, R = Ph, But) are reported as the first examples of thiols bound to zerovalent d6 metals. An X-ray crystal structure determination of (ButSH)Cr(CO)5 found minor distortions from octahedral geometry about the Cr; two carbonyls are bent below the equatorial plane by 6° in response to the bulky But group. The 〈Cr-S-C and 〈Cr-S-H angles are 121.3 (2) and 106°, respectively, and the Cr-S distance of 2.439 (2) A? is significantly shorter than that of the anion, (ButS)Cr(CO)5- (2.479 (1) A?). The complex crystallized in the monoclinic space group P21/n, with a = 6.545 (2) A?, b = 10.918 (2) A?, c = 17.731 (4) A?, β = 97.58 (2)°, V = 1256.0 A?3, and Z = 4. Restricted force field calculations (Cotton-Kraihanzel approximation) of the CO stretching force constants are used to contrast the RSH ligands with amines and phosphines according to their ability as σ-donating ligands (RSH 3 3) and as π-accepting ligands (NR3 3). When RSH ligands bind to the Cr(CO)5 moiety, the acidity of the thiols is moderately increased. There is no indication of S-H oxidative addition of isolated (ButSH)Cr(CO)5, (PhSH)Cr(CO)5, or cis-(ButSH)Cr-(CO)4(PEt3) in solution, under either photochemical or thermal conditions. The most easily accessible reaction path is RSH ligand loss.
