Experimental Raman spectra of dilute and laser-light-sensitive [Rh(4)(CO)(9)(mu-CO)(3)] and [(mu(4)-eta(2)-3-hexyne)Rh(4)(CO)(8)(mu-CO)(2)]. Comparison with theoretically predicted spectra

The reaction of Rh(4)(CO)(9)(mu-CO)(3)] with 3-hexyne to form the butterfly cluster (mu(4)-eta(2)-3-hexyne)Rh(4)(CO)(8)(mu-CO)(2)] was monitored viain-situ Raman spectroscopy using an NIR laser source, at room temperature and under atmospheric argon using n-hexane as solvent. The collected raw spectra were deconvoluted using band-target entropy minimization (BTEM). The pure component mid-Raman spectra of the Rh(4)(CO)(9)(mu-CO)(3)] and the butterfly cluster (mu(4)-eta(2)-3-hexyne)Rh(4)(CO)(8)(mu-CO)(2)], were reconstructed with a high signal-to-noise ratio. Full geometric optimization and Raman vibrational prediction were carried out using DFT. The experimental and predicted Raman spectra were in good agreement. In particular, the far-Raman vibrational modes in the region 100-280 cm(-1) provided characterization of the metal-metal bonds and direct confirmation of the structural integrity of the polynuclear frameworks in solution.