Molybdenum nitrides have been employed in a variety of applications. For use in catalysis, the cubic γ phase with the nominal stoichiometry Mo 2 N and the space group Fm3̅ m is typically prepared by high-temperature reaction of MoO 3 with NH 3 . The literature presents conflicting reports of the possible presence of residual oxygen from typical ammonolysis reactions and whether such species influence the crystal structure and morphology. With the aim of resolving these open questions, a comprehensive study of the chemistry, crystal structure, and electronic structure of molybdenum nitride materials prepared by ammonolysis has been undertaken here, with particular focus on the role of reaction temperature. Ammonolysis of MoO 3 was carried out at 973 and 1073 K and yielded single-phase cubic products. Using electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis, prompt gamma-ray neutron activation analysis, and combustion analysis, significant concentrations of oxygen and, to a lesser extent, hydrogen were found in both materials. The crystal structure of each phase was refined by Rietveld analysis using combined synchrotron X-ray diffraction and neutron diffraction data. The structures were found to be derivatives of the B1 rock salt (halite) structure, as is often reported for "γ-Mo 2 N." However, both materials adopt the space group Pm3̅ m, as opposed to the typically presumed space group of Fm3̅ m, and both have much higher anion content than implied by the stoichiometry Mo 2 N. Ordering of cation vacancies and of anion species is responsible for the loss of the translational symmetry expected for the space group Fm3̅ m. X-ray absorption spectroscopy studies, along with the EELS and XPS results, showed the Mo oxidation state to be diminished with higher temperature synthesis, consistent with the retention of a lower concentration of anions and in particular oxygen. The difficulty in differentiating oxygen and nitrogen and the impossibility of detecting hydrogen by X-ray and electron diffraction methods, especially in the presence of the heavy element Mo, have likely inhibited accurate identification of Mo 1−x (N 1−y O y )H z as the product of MoO 3 ammonolysis. The findings reported here offer a critical assessment for understanding the properties of molybdenum "nitrides" in electronic and catalytic applications.

<p>Novel ring-disubstituted isobutyl phenylcyanoacrylates, RPhCH=C(CN)CO₂CH₂CH(CH₃)₂ (where R is 2,5-dibromo, 3,5-dibromo, 2,3-dichloro, 2,4-dichloro, 2,5-dichloro, 2,6-dichloro, 3,4-dichloro, 3,5-dichloro) were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-disubstituted benzaldehydes and isobutyl cyanoacetate and characterized by CHN analysis, IR, ¹H and ¹³C NMR. The acrylates were copolymerized with styrene in solution with radical initiation (ABCN) at 70C. The compositions of the copolymers were calculated from nitrogen analysis.</p>

Novel dibromo and dichloro ring-disubstituted isobutyl phenylcyanoacrylates, RPhCH=C(CN)CO2CH2CH(CH3)2 (where R is 2,5-dibromo, 3,5-dibromo, 2,3-dichloro, 2,4-dichloro, 2,5-dichloro, 2,6-dichloro, 3,4-dichloro, 3,5-dichloro) were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-disubstituted benzaldehydes and isobutyl cyanoacetate and characterized by CHN analysis, IR, 1H and 13C NMR. The acrylates were copolymerized with styrene in solution with radical initiation at 70C. The compositions of the copolymers were calculated from nitrogen analysis.

Novel alkyl ring-substituted t-butyl phenylcyanoacrylates, RPhCH=C(CN)CO2C(CH3)3 (where R is H, 2-methyl, 3-methyl, 4-methyl, 2-ethyl, 4-ethyl, 4-propyl, 4-i-propyl, 4-butyl, 4-i-butyl) were prepared and copolymerized with styrene. The acrylates were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and t-butyl cyanoacetate, and characterized by CHN analysis, IR, 1H and 13C NMR. All the ethylenes were copolymerized with styrene in solution with radical initiation (ABCN) at 70C. The compositions of the copolymers were calculated from nitrogen analysis.