Arene Molybdenum Lab
Arene Molybdenum lab
Introduction:
Organometallic chemistry is the study of chemical compounds that contain carbon atoms bound to a metal atom. Organometallic compounds can contain main group elements, or more metallic elements such as zinc or carbon. These compounds tend to have carbon atoms bound to the metal center by σ-bonds. Alternatively, transition metals can be involved in the compound, which leads to a variety of interesting and diverse chemical characteristics. For example, a promising use of Mo(CO)6 is in the fabrication of nanowires used in electronic and optoelectronic devices1, where gaseous Mo(CO)6 is reacted with oxygen and then deposited on an SiO2 substrate. Another entirely different use of this complex is in the synthesis of potential fire retardants, that uses Mo(CO)6 and 4-chlorophenol to catalyze polymerization reactions2 (By way of the Bunz Adimet process). The metal-carbon bonding in these transition metal complexes often have localized metal to carbon σ-bonding, and a degree of π-back bonding, which is well observed in carbonyl containing species. π-back bonding occurs when empty π* (anti bonding) orbitals accepts electrons from the metal center’s d-orbitals. Back bonding allows metals like Mo to exist in a wide range of oxidation states, as it allows the metal to distribute electron density to the ligand. When back bonding occurs, it causes the M-C bond to shorten, and the C-O bond lengthens6. In this lab, molybdenum hexacarbonyl (Mo(CO)6) was used to synthesize 3 different compounds, (η6-C6H3(CH3)3)Mo(CO)3, Mo(CO)5dppm and Mo(CO)4C2H6N2. Each of these compounds replaces either 1, 2 or 3 carbonyl groups from the Mo center with a different ligand. From these compounds, observations about how changing out CO ligands will affect the remaining CO bonds can be seen. Since it is hypothesized that by replacing a CO ligand with a different ligand, the IR stretch of the remaining CO bonds will be shifted to a lower IR frequency if the ligand
Introduction:
Organometallic chemistry is the study of chemical compounds that contain carbon atoms bound to a metal atom. Organometallic compounds can contain main group elements, or more metallic elements such as zinc or carbon. These compounds tend to have carbon atoms bound to the metal center by σ-bonds. Alternatively, transition metals can be involved in the compound, which leads to a variety of interesting and diverse chemical characteristics. For example, a promising use of Mo(CO)6 is in the fabrication of nanowires used in electronic and optoelectronic devices1, where gaseous Mo(CO)6 is reacted with oxygen and then deposited on an SiO2 substrate. Another entirely different use of this complex is in the synthesis of potential fire retardants, that uses Mo(CO)6 and 4-chlorophenol to catalyze polymerization reactions2 (By way of the Bunz Adimet process). The metal-carbon bonding in these transition metal complexes often have localized metal to carbon σ-bonding, and a degree of π-back bonding, which is well observed in carbonyl containing species. π-back bonding occurs when empty π* (anti bonding) orbitals accepts electrons from the metal center’s d-orbitals. Back bonding allows metals like Mo to exist in a wide range of oxidation states, as it allows the metal to distribute electron density to the ligand. When back bonding occurs, it causes the M-C bond to shorten, and the C-O bond lengthens6. In this lab, molybdenum hexacarbonyl (Mo(CO)6) was used to synthesize 3 different compounds, (η6-C6H3(CH3)3)Mo(CO)3, Mo(CO)5dppm and Mo(CO)4C2H6N2. Each of these compounds replaces either 1, 2 or 3 carbonyl groups from the Mo center with a different ligand. From these compounds, observations about how changing out CO ligands will affect the remaining CO bonds can be seen. Since it is hypothesized that by replacing a CO ligand with a different ligand, the IR stretch of the remaining CO bonds will be shifted to a lower IR frequency if the ligand