You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Insertion of CO2 and COS into Bi-C Bonds: Reactivity of a Bismuth NCN Pincer Complex of an Oxyaryl Dianionic Ligand, [2,6-(Me2NCH2)2C6H3]Bi(C6H2tBu2O). The reactivity of the unusual oxyaryl dianionic ligand, (C6H2tBu2-3,5-O-4)2-, in the Bi3+ NCN pincer complex Ar'Bi(C6H2tBu2-3,5-O-4), 1, [Ar' = 2,6-(Me2NCH2)2C6H3] has been explored with small molecule substrates and electrophiles. The first insertion reactions of CO2 and COS into Bi-C bonds are observed with this oxyaryl dianionic ligand complex. These reactions generate new dianions that have quinoidal character similar to the oxyaryl dianionic ligand in 1. The oxyarylcarboxy and oxyarylthiocarboxy dianionic ligands were identified by X-ray crystallography in Ar'Bi[O2C(C6H2tBu2-3-5-O-4)-κ2O,O'], 2 and Ar'Bi[OSC(C6H2tBu2-3-5-O-4)-κ2O,S], 3, respectively. Silyl halides and pseudohalides, R3SiX (X = Cl, CN, N3; R = Me, Ph), react with 1 by attaching X to bismuth and R3Si to the oxyaryl oxygen to form Ar'Bi(X)(C6H2tBu2-3,5-OSiR3-4) complexes, a formal addition across five bonds. These react with additional R3SiX to generate Ar'BiX2 complexes and R3SiOC6H3tBu2-2,6. The reaction of 1 with I2 forms Ar'BiI2 and the coupled quinone, 3,3',5,5'-tetra-tert-butyl-4,4'-diphenoquinone, by oxidative coupling.
{"Chemical": ["COS", "Oxyaryl", "oxyarylthiocarboxy", "Bismuth NCN", "I2", "Silyl halides", "R3SiX", "Ar\u0027Bi[OSC(C6H2tBu2-3-5-O-4)-\u03ba2O,S]", "R3SiOC6H3tBu2-2,6", "oxyaryl", "quinone", "Bi-C", "Bi3+ NCN", "2,6-(Me2NCH2)2C6H3", "Ar\u0027BiI2", "Ar\u0027BiX2", "(C6H2tBu2-3,5-O-4)2", "Ar\u0027Bi(C6H2tBu2-3,5-O-4)", "Me", "bismuth", "Ar\u0027Bi(X)(C6H2tBu2-3,5-OSiR3-4)", "CO2", "[2,6-(Me2NCH2)2C6H3]Bi(C6H2tBu2O)", "oxygen", "Ar\u0027Bi[O2C(C6H2tBu2-3-5-O-4)-\u03ba2O,O\u0027]", "Ph", "CN", "3,3\u0027,5,5\u0027-tetra-tert-butyl-4,4\u0027-diphenoquinone", "oxyarylcarboxy", "pseudohalides", "Cl", "N3", "R3Si"]}