Synthesis and spectroscopy of cyanotriacetylene (HC7N) in solid argon

Synthesis and Electronic Phosphorescence of Dicyanooctatetrayne (NC10N) in Cryogenic Matrixes

The rodlike 1,8-dicyano-octa-1,3,5,7-tetrayne (NC₁₀N) molecule was synthesized with UV-assisted coupling of rare-gas matrix-isolated cyanobutadiyne (HC₅N) molecules. Detection of NC₁₀N molecule was possible due to its strong orange-red (origin at 618 nm) electronic luminescence. Excitation spectra of this emission (ã ³Σ_u⁺-X̃ ¹Σ_g⁺ phosphorescence) gave access to studying the fully allowed H̃ ¹Σ_u⁺-X̃ ¹Σ_g⁺ UV system of NC₁₀N. The identification of observed spectral features was assisted with quantum chemical computations. Certain regularities shaping the electronic spectroscopy of NC_{2 n}N molecules have been discussed.

Bound and continuum-embedded states of cyanopolyyne anions

Equation-of-motion coupled-cluster calculations reveal systematic trends across bound and continuum-embedded excited states in cyanopolyyne anions.

Low Temperature Synthesis and Phosphorescence of Methylcyanotriacetylene

This paper reports on UV-stimulated synthesis of methylcyanotriacetylene carried out in cryogenic rare gas matrixes via coupling of smaller precursors: propyne and cyanodiacetylene. The detection was possible due to the strong visible ã ³A' → X̃ ¹A₁ phosphorescence of CH₃C₇N, discovered in the course of this work. The ensuing measurements of electronic spectroscopy revealed the formally forbidden B̃ ¹E-X̃ ¹A₁ system, as well as the allowed one Ẽ ¹A₁-X̃ ¹A₁, with origins at approximately 3.32 and 5.4 eV, respectively. It was also possible to revisit the spectroscopic characterization of cyanotriacetylene, HC₇N, formed in parallel to the title photoproduct. Spectral assignments were assisted with a density functional theory study.

Cryogenic Photochemical Synthesis and Electronic Spectroscopy of Cyanotetracetylene

HC₉N is a molecule of astrochemical interest. In this study, it was produced in cryogenic Ar and Kr matrices from UV-photolyzed diacetylene/cyanodiacetylene mixtures. Its strong phosphorescence was discovered and served for the identification of the compound. Vibrationally resolved phosphorescence excitation spectra gave insight into excited singlet electronic states. Two electronic systems were observed around 26 000-34 000 cm^-1 and 35 000-50 000 cm^-1. Energies of the second excited singlet and the lowest triplet state were derived from analysis of these systems. Vibrational and electronic spectroscopic features were assigned with the assistance of density functional theory calculations. Some trends concerning the electronic spectroscopy of HC_2n+1N family molecules are presented.