UC Santa Barbara

Reacting the known [K(18-crown-6)(THF)2][CPh3] with excess CS2 yields a novel dithiocarboxylate, [K(18-crown-6)][S2CCPh3] (2.1). Further reaction of 2.1 with 0.5 equiv. of I2 yields the thiocarbonyl disulfide Ph3CC(S)SS(S)CCPh3 (2.2). Alternatively, reaction of 2.2 with 1 equiv. Ph3CCl yields the dithiocarboxylate ester Ph3CC(S)SCPh3 (2.3). Compounds 2.1-2.3 were characterized by NMR, IR, and UV-Vis spectroscopy, as well as X-ray diffraction. Additionally, compounds 2.2 and 2.3 were investigated as potential photolytic CS2 delivery agents. Photolysis of 2.2 in a medium-pressure Hg lamp photolysis chamber for 24 h yields Ph3CSSCPh3, 2.3, triphenylmethane, 9-phenylfluorene, triphenylmethanethiol, the unreported Ph3CC(S)SSH (2.4), as well as CS2 in a 50% yield. Photolysis of 2.3 in a medium-pressure Hg lamp photolysis chamber for 6 h also yields Ph3CSSCPh3, triphenylmethane, 9-phenylfluorene, triphenylmethanethiol, and (2.4). However, in this photolysis, the yield of CS2 is only 8%, which suggests that CS2 is not one of the major pathways of this reaction.Rather than small molecule delivery, trityl molecules can also be used as M(0) synthons. After synthesizing the organocobalt complex [Co(η5 -CPh3)(η2 ,η2 -1,5-cod)], reacting it further with tBuNC or CO yields the expected dicobalt M(0) complexes. This suggests that [Co(η5 - CPh3)(η2 ,η2 -1,5-cod)] can be used as a Co(0) synthon. With this result in mind, reacting [Co(η5 -CPh3)(η2 ,η2 -1,5-cod)] with 2 equiv. of PEt3 at 60 °C yields [Co(η5 -CPh3)(PEt3)] (3.1). Further reaction of 3.1 with varying amounts of SePEt3 at 80 °C leads to the formation of Co9Se6(PEt3)8, Co8Se6(PEt3)8 (3.2), and Co6Se6(PEt3)6 (3.3), identified via ESI-MS and X-ray diffraction in the case of 3.2 and 3.3. The observed lability of the 1,5-cod ligand at elevated temperatures makes 3.1 a favorable intermediate for cluster formation, making [Co(η5 - CPh3)(η2 ,η2 -1,5-cod)] a good candidate for future cluster syntheses.