Articles written in Journal of Chemical Sciences

• Synthesis of monomeric and polymeric alkali and alkaline earth metal complexes using a phosphinoselenoic amide ligand in metal coordination sphere

We report the monomeric complexes of magnesium and calcium of composition [M(THF)$_n${$\eta^2$-Ph2P(Se)N(CMe3)}2] [M= Mg (3), n = 1 andM = Ca (4), n = 2)] and polymeric complexes of potassium and barium of composition [K(THF)2{Ph2P(Se)N(CMe3)}]$_n$ (2) and [K(THF)Ba{Ph2P(Se)N(CMe3)}3]$_n$(5) respectively. The potassium complex 2 was readily prepared by the reaction of potassium bis(trimethylsilyl)amide with phosphinoselenoic amide ligand (1) at ambient temperature. The calcium complex 4 was prepared by two synthetic routes: in the first method, commonly known as salt metathesis reaction, the potassium complex 2 was made to react with alkaline earth metal diiodide at room temperature to afford the corresponding calcium complex. The metal bis(trimethylsilyl)amides were made to react with protic ligand 1 in the second method to eliminate the volatile bis(trimethyl)silyl amine. The magnesium complex 3 and barium complex 5 were prepared only through the first method. Solid-state structures of all the new complexes were established by single crystal X-ray diffraction analysis. The smaller ionic radii of Mg2+ (0.72Å) and Ca2+ (0.99Å) ions form the monomeric complex, whereas the larger ions K+ (1.38Å) and Ba2+ (1.35Å) were found to form onedimensional polymeric complexes with monoanionic ligand 1. Compound 2 serves an example of magnesium complex with a Mg-Se direct bond.

• Formation of BH3 Adducts with Pyridine-2-Methylaminophosphine ligands: An experimental and computational study

The reaction of pyridine-2-methylaminophosphine [C5H4N-CH2NHPPh2] (1) and pyridine-2-methylphosphinoselenoic amide [C5H4N-CH2NHP(Se)Ph2] (2) with BH3·SMe2 yields the corresponding adducts [C5H4N(BH3)-CH2NHP(BH3)Ph2] (1a), and [C5H4N(BH3)-CH2NHP(Se)Ph2] (2a), respectively. The solid state structures of both the compounds were established by single crystal X-ray diffraction analysis. The phosphorus and the pyridine nitrogen atoms are coordinated to the boron atom in the case of 1a whereas only pyridine nitrogen atom is attached to the BH3 group in the case of 2a. To understand the nature of P-B/ N-B bonds and to compare the basicities of pyridine nitrogen, amino nitrogen and phosphorus atoms, density functional theoretical (DFT) calculations were performed on the BH3 adducts 1a and 2a. The results are consistent with the experimental results.

• # Journal of Chemical Sciences

Volume 132, 2020
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