A new possibility of a Rh(I) complex is demonstrated. An inverted sandwich Rh(I) complex bearing a dianionic plumbole ligand was synthesized by the reaction a dilithioplumbole with [Rh(cod)Cl] 2 . The plumbole ligand functions as a π-donor stronger than the cyclopentadienyl ligand, as evidenced by quantum-chemical calculations. The Rh(I)−plumbole complex can be applied as a catalyst for an intramolecular [2+2+2] cycloaddition reaction of a triyne.

A series of some aryl hydrazides have been synthesized. These hydrazides purities were analyzed by physical constants and spectral data. The assigned spectral group frequencies were correlated with Hammett substituent constants and Swain-Lupton parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the spectral group frequencies has been discussed

Density functional theory (DFT) and zeroth-order regular approximation DFT calculations were performed to investigate the electronic structures and 13C and 207Pb nuclear magnetic resonance (NMR) chemical shifts of metal-coordinated plumboles, namely, mono­rho­dio­plumbole ([Rh–plumbole]−), di­rhodio­plumbole (Rh2–plumbole), and di­lithio­plumbole (Li2–plumbole), which have a five-membered ring containing lead. The molecular orbital correlation diagram and extended transition state–natural orbitals for chemical valence analysis of the [Rh–plumbole]− and Rh2–plumbole complexes showed that the plumbole is primarily a π-donor, with π-donation being dominant in the Rh2–plumbole complex. The present calculations show that the Pb–Cα internuclear distances are longer in the Rh2–plumbole complex than in [Rh–plumbole]− because of the combined effect of strong π-donation and weak π-back-donation in the Rh2–plumbole complex. The calculated 207Pb and 13Cα NMR chemical shifts agree with the experimental trends reasonably well. The influences of the relativistic effect, role of the functional, effect of the solvent, and dependence of the exact exchange admixture on the calculated 207Pb and 13Cα NMR chemical shifts were investigated. The NMR chemical shift trend of the 207Pb atom in the complexes originates from the paramagnetic and spin–orbit contributions. NMR component analysis revealed that the upfield shift of the 13Cα atoms of the [Rh–plumbole]− and Rh2–plumbole complexes compared to that of the Li2–plumbole complex is mainly due to the decrease in the paramagnetic term.

Identification of methyl acetate in the interstellar medium (ISM) and its spectroscopic studies have prompted us to investigate the structure of crystalline methyl acetate using numerical calculations. Here, we present a theoretical study of the structure of crystalline methyl acetate and its isotopologues and compare the calculated infrared (IR) spectra with the available experimental data. The optimized structure and vibrational properties were calculated using SIESTA software at 0 K. In the optimization process, the Perdew-Burke-Ernzerhof functional and conjugate gradient methods were used with double zeta polarization basis functions. After optimization of the periodic structure, the vibrational frequencies and normal modes were calculated within the harmonic approximation. Using the calculated results, we refine the mode assignments of experimental work on crystalline methyl acetate and determine the low frequency modes (below 650 cm(-1)). To investigate the accuracy of the pseudopotential and confirm the IR frequencies, we performed molecular calculations using a periodic model of methyl acetate and its isotopologues using SIESTA and compared them with results obtained from Gaussian 09 (all electron method) calculations. Finally, we assigned the vibrational modes of crystalline CD3-COO-CH3 and CH3-COO-CD3, for which experimental data are not available in the crystalline phase under ISM conditions. For all of the calculation methods, the IR vibrational modes of molecular and crystalline methyl acetate and its isotopologues were in good agreement with the available experimental data and predict the unavailable values.