Intermolecular Electronic Coupling of Organic Units for Efficient Persistent Room‐Temperature Phosphorescence

Although persistent room‐temperature phosphorescence (RTP) emission has been observed for a few pure crystalline organic molecules, there is no consistent mechanism and no universal design strategy for organic persistent RTP (pRTP) materials. A new mechanism for pRTP is presented, based on combining the advantages of different excited‐state configurations in coupled intermolecular units, which may be applicable to a wide range of organic molecules. By following this mechanism, we have developed a successful design strategy to obtain bright pRTP by utilizing a heavy halogen atom to further increase the intersystem crossing rate of the coupled units. RTP with a remarkably long lifetime of 0.28 s and a very high quantum efficiency of 5 % was thus obtained under ambient conditions. This strategy represents an important step in the understanding of organic pRTP emission.     

Levi Extension Theorems for Meromorphic Functions of Weak Type in Infinite Dimension

The aim of paper is to give some results, that prepare for studying the problem on cross theorems for separately \((\cdot , W)\)-meromorphic functions. Some general versions of extension theorem of Levi type are extended to the classes of meromorphic functions f on \(D \times (\Delta _r {\setminus } \overline{\Delta })\) with values in a locally convex space F. Here, the function f is assumed that, for each \(z \in D_*,\) the function \(f_z = f(z, \cdot )\) has a (F, W)-meromorphic extension to \(\Delta _r,\) where F is either a locally (or sequentially) complete locally convex space or a Fréchet space, the space \(W \subseteq F'\) is separating (or determines boundedness), \(\Delta _r = \{\lambda \in {\mathbb C}: |\lambda | < r\}\) with \(r > 1, \Delta = \Delta _1\) and D is either a domain in \({\mathbb C}^n\) or a balanced domain in a Fréchet space containing a non-pluripolar balanced convex compact subset, \(D_*\) is dense in D.     

A non-empirical molecular orbital study of valence tautomers of C2H3N

The valence tautomers of C₂H₃N have been examined by non-empirical molecular orbital calculations using two split-valence shell basis sets. All geometries were fully optimized using the 4–31G basis set and these structures were then used in 6–31G basis set calculations. The order of stability of the three possible cyclic isomers is 1-azirine > cyclic carbene > 2-azirine. The profiles for conversion of vinylmethylene into cyclopropene, vinylnitrene into 1-arizine, and iminomethylene into 2-azirine have all been shown to have barriers.     

An AB initio molecular orbital study of ten isomers on the C2SiH4 energy surface

Double-zeta basis set calculations employing gradient techniques have been used to locate minima on the C₂SiH₄ energy hypersurface. 3-silapropyne is the most stable molecule and structures containing divalent silicon are more stable than those containing carbon-silicon multiple bonds. Inclusion of polarisation functions is most important for cyclic structures.     

Optimum Gaussian basis set for the Bromine atom. Ab initio calculations on the HBr molecule

An optimum (15 ^s 12 ^p 2 ^d ) Gaussian basis set was obtained for the Bromine atom by minimizing the open shell energy functional. In the minimization procedure the method of conjugate gradients was applied. The optimum (15 ^s 12 ^p 2 ^d ) basis set was contracted to an [8 ^s 6 ^p 2 ^d ] “double zeta” quality basis set and this contracted set was tested on the HBr molecule.     

Synthesis and Cytotoxicity of 6‐Pyrrolidinyl‐2‐(2‐Substituted Phenyl)‐4‐Quinazolinones

In our continuing search for potential anticancer candidates, 2‐(3‐methoxyphenyl)‐6‐pyrrolidinyl‐4‐quinazolinone ( JJC‐1 ) was selected as the lead compound. Starting 5‐pyrrolidinyl‐2‐aminobenzamide was prepared using standard methodology from 5‐chloro‐2‐nitrobenzoic acid by reaction with SOCl₂, NH₃, pyrrolidine, and H₂. The starting benzamide then was reacted with 2‐substituted benzaldehyde or benzoyl chloride in N,N‐dimethylacetamide (DMAC) in the presence of NaHSO₃ at 150 °C. Thermal cyclodehydration/dehydrogenation gave the target 6‐pyrrolidinyl‐2‐(2‐substituted phenyl)‐4‐quinazolinones ( 15–22 ). These target compounds were assayed for their cytotoxicity in vitro against six cancer cell lines, including human monocytic leukemia cells (U937), mouse monocytic leukemia cells (WEHI‐3), human hepatoma cells (HepG2, Hep3B) and human lung carcinoma cells (A549, CH27). Most of them exhibited significant cytotoxic effect toward U937 and WEHI‐3 cells, with EC₅₀ values ranging from 0.30 to 10.10 μM. Compound 19 was investigated further for its action mechanisms. Preliminary findings indicated that compound 19 induced G2/M arrest and apoptosis on U937 cells.