Highly Stereoselective 1,3-Dipolar Cycloaddition of Nitrones to (Nitrile)2PtII Species Furnishing Diastereomerically Pure 2,3-Dihydro-1,2,4-oxadiazole Ligands

Zinc(ii)-mediated generation of 5-amino substituted 2,3-dihydro-1,2,4-oxadiazoles and their further ZnII-catalyzed and O2-involving transformations

Zn^II-activated cyanamides NCNR₂ react with the acyclic N-alkyl ketonitrones Ph₂CN⁺(O⁻)R′ achieving uncomplexed 2,3-dihydro-1,2,4-oxadiazoles.

Dichloridobis[3-(4-chloro-phen-yl)-2,N,N-trimethyl-2,3-di-hydro-1,2,4-oxa-diazole-5-amine-κN (4)]platinum(II)-4-chloro-benzaldehyde (1/1)

In the title 1:1 co-crystal, [PtCl2(C11H14ClN3O)2]·C7H5ClO, the coordination polyhedron of the Pt(II) atom is slightly distorted square-planar with the chloride and 2,3-di-hydro-1,2,4-oxa-diazole ligands mutually trans, as the Pt atom lies on an inversion center. The 4-chloro-benzaldehyde mol-ecules are statistically disordered about an inversion centre with equal occupancies for the two positions. The Pt(II) complex forms a three-dimensional structure through C-H⋯Cl and weaker C-H⋯O inter-actions with the 4-chloro-benzaldehyde mol-ecule.

Dichloridobis[3-(4-meth-oxy-phen-yl)-2-methyl-5-(piperidin-1-yl)-2,3-di-hydro-1,2,4-oxa-diazole-κN (4)]platinum(II)

In title compound, [PtCl2(C15H21N3O2)2], the Pt(II) cation, located on an inversion center, is coordinated by two Cl(-) anions and two 3-(4-meth-oxy-phen-yl)-2-methyl-5-(piperidin-1-yl)-2,3-di-hydro-1,2,4-oxa-diazole ligands in a distorted Cl2N2 square-planar geometry. The di-hydro-oxa-diazole and piperidine rings display envelope (with the non-coordinating N atom as the flap atom) and chair conformations, respectively. In the crystal, weak C-H⋯Cl hydrogen bonds link the mol-ecules into supra-molecular chains running along the b axis. The piperidine ring is disordered over two positions with the occupancy ratio of 0.528 (4):0.472 (4).

Tetra-butyl-ammonium 2-[2,5-dimethyl-3-(4-nitro-phen-yl)-2,3-dihydro-1,2,4-oxadiazo-lium-4-yl]nona-hydro-closo-deca-borate

The title ionic compound, C16H36N(+)·C10H20B10N3O3(-), consists of a tetra-butyl-ammonium cation and a closo-deca-borate cluster anion, which is bound to the substituted 2,3-dihydro-1,2,4-oxadiazole ring through a B-N bond [1.540 (2) Å]. The distances between connected B atoms in the deca-borate cluster range from 1.689 (2) to 1.844 (2) Å. The 2,3-dihydro-1,2,4-oxadiazole ring adopts an envelope conformation with the N atom as the flap atom.

cis-Tetra-chloridobis(1H-imidazole-κN(3))platinum(IV)

In the title complex, cis-[PtCl(4)(C(3)H(4)N(2))(2)], the Pt(IV) ion lies on a twofold rotation axis and is coordinated in a slightly distorted octa-hedral geometry. The dihedral angle between the imidazole rings is 69.9 (2)°. In the crystal, mol-ecules are linked by N-H⋯Cl hydrogen bonds, forming a three-dimensional network.