Photodissociation of Solvated Metal Cation Complexes Mg+(OCNC2H5)n (n = 1−3)

Ethyl isocyanate-solvated magnesium cation complexes Mg + (OCNC 2 H 5 ) n were produced in a laser-ablation supersonic expansion nozzle source. Photoinduced reactions in the complexes of Mg + (OCNC 2 H 5 ) n ( n = 1−3) have been studied as a function of the number of solvent molecules. Photodissociation action spectra of Mg + (OCNC 2 H 5 ) 1 - 3 were recorded in the spectral range of 230−440 nm. Except for minor reactive products C 2 H 5 + and Mg + OCN at short wavelengths from the photoreaction of the singly solvated complex Mg + (OCNC 2 H 5 ), only evaporation products were observed from photodissociation of Mg + (OCNC 2 H 5 ) n ( n = 1−3). For all three complexes we studied, the ligands are believed to be in the first solvation shell. The action spectra of Mg + (OCNC 2 H 5 ) 1 - 3 consist of two or three peaks on the red and blue sides of the Mg + 3 2 P ← 3 2 S atomic transition. The ground-state geometries of Mg + (OCNC 2 H 5 ) 1 - 3 were fully optimized at the B3LYP/6-31+G** level by using the GAUSSIAN 98 package. The absorption spectra of the complexes Mg + (OCNC 2 H 5 ) 1 - 3 were calculated by using the optimized structures of their ground states with the CIS/6-31+G** method. The theoretical predictions appear to be consistent with the experimental results. An sp hybridization mechanism was proposed for the complexation of Mg + and OCNC 2 H 5, which results in the formation of big π bonds between the magnesium cation and the ethyl isocyanate molecule, and further rationalizes the nearly linear backbone of Mg + −O−C−N−C in the complex Mg + (OCNC 2 H 5 ).