Peiju Yang

Magnesium−Magnesium Bond Stabilized by a Doubly Reduced α-Diimine: Synthesis and Structure of [K(THF)3]2[LMg−MgL] (L = [(2,6-iPr2C6H3)NC(Me)]22−)

A new Mg-Mg-bonded compound stabilized by a doubly reduced alpha-diimine ligand, [K(THF)(3)](2)[LMg-MgL] (L = [(2,6-(i)Pr(2)C(6)H(3))NC(Me)](2)(2-)), has been synthesized and characterized by single-crystal X-ray diffraction and density functional theory analysis. The Mg-Mg bond length is 2.9370(18) A.

Tris Chelating Phosphate Complexes of Bis(thio)urea Ligands

Two bisurea (L(1), L(2)) and one bisthiourea (L(3)) ligands were synthesized and their anion coordination behavior was studied. These ligands can readily form the tris chelates [PO4(L)3](3-) (1, 5, and 6) with phosphate ion (PO4(3-)) in the solid state, in which the anion is coordinated by six urea groups through 12 hydrogen bonds. Solution binding studies by (1)H NMR and UV-vis spectroscopy revealed different binding properties of the ligands toward phosphate ion. While the bis(p-nitrophenyl)-substituted bisurea L(1) retains the 3:1 (host to guest) binding ratio in solution, the diethyl derivative L(2) only forms 1:1 complex with phosphate ion. The more acidic thiourea L(3) undergoes deprotonation/decomposition in the presence of phosphate ion. Moreover, the sulfate complex (2) of L(1) and bicarbonate (3) and carbonate (4) complexes of L(2) have also been obtained, which show lower coordination numbers both in the solid state and in solution.

Isolation of the Half-Condensed Pyrazoline Intermediates en Route to N-(1,10-Phenanthroline)-pyrazole Derivatives from the Knorr Reaction

Abstract During the synthesis of 2-pyrazole-1,10-phenanthroline derivatives by the Knorr reaction from benzoylacetone and 2-hydrazine-1,10-phenanthroline, three half-condensed intermediates, the 5-hydroxyl pyrazolines (2b–2d), were isolated and characterized by NMR spectroscopy and x-ray diffraction (for 2b and 2d). These pyrazoline intermediates could be readily dehydrated under the catalysis of acetic acid to afford the corresponding pyrazoles with high regioselectivity.

Dichlorido(2-chloro-9-mesityl-1,10-phenanthroline-κ2N,N′)cobalt(II) dichloro­methane hemisolvate

The title compound, [CoCl2(C21H17ClN2)]·0.5CH2Cl2, crystallizes from dichloromethane as a 2:1 solvate [CoCl2L]2·CH2Cl2 (L is 2-chloro-9-mesityl-1,10-phenanthroline). There are two independent CoCl2 L molecules in the asymmetric unit and both molecules have similar conformations. They are connected by a weak C—H⋯π interaction involving the mesityl ring. The cobalt center is four-coordinated by the two N-atom donors of the bidentate ligand and two chloride ions in a distorted tetrahedral geometry. The packing of the molecules is stabilized by weak slipped π–π stacking interactions between symmetry-related phenanthroline groups.