Synthesis, characterization, and liquid injection field desorption ionization mass spectrometry analysis of pincer ligated group 6 (Cr, Mo, W) carbonyl complexes

We report the synthesis of molybdenum and tungsten bromo dicarbonyl complexes (POCOPtBu)MIIBr(CO)2 (M = Mo or W; POCOPtBu = κ3-C6H3-1,3-[OP(tBu)2]2) supported by an anionic PCP pincer ligand, and the chromium complex (PNPtBu)Cr0(CO)3 (PNPtBu = 2,6-bis(di-tert-butyl-phosphinomethyl)pyridine) bearing a neutral PNP pincer scaffold. The three group six complexes described in this study have been characterized by Liquid Injection Field Desorption Ionization Mass Spectrometry (LIFDI-MS), NMR, and IR spectroscopy. Single crystal X-ray diffraction studies show the MoII and WII complexes adopt a six-coordinate distorted trigonal prismatic geometry, whereas the Cr0 complex exhibits a distorted octahedral geometry.