3-Amino-1-propanol and N-methylaminoethanol: coordination to zinc(ii) vs. decomposition to ammonia

The coordination of amino alcohols 3-amino-1-propanol and N-methylaminoethanol to zinc(ii) and their decomposition to ammonia were investigated.

Five complexes based on a new racemic tetraoxaspiro ligand: correlation of potential coordination preferences with the structure, magnetic properties and luminescence properties

A new ligand, rac-(R,S)-3,9-bis(pyridin-3-yl)-2,4,8,10-tetraoxaspiro[5.5]undecane ((R,S)-bptu), is synthesized, and five novel complexes, namely, {[Cu[(R,S)-bptu]Cl2]·0.5NMP}n (1), {[Zn[(R,S)-bptu]Cl2]·CH3CN}n (2), {Cd2[(R,S)-bptu]2Cl4(NMP)2}n (3), {[Cd[(R,S)-bptu]2Cl2]·2CH3CN}n (4), and {Cd3[(R,S)-bptu]2Cl6(DMF)2}n (5), (NMP = N-methyl-2-pyrrolidone, DMF = N,N-dimethylformamide), are obtained via a layered diffusional reaction. (R,S)-bptu and complexes 1-5 are characterized by single-crystal X-ray diffraction, element analyses, powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA). Complexes 1-3 show three different 1D structures: 1 is a mesomeric looped chain, 2 is a racemic helix compound, and 3 is a mesomeric zigzag chain, while 4 and 5 are two different mesomeric 2D structures, of which 4 is a 2D wave-like layer and 5 is a 2D cellular layer. Structural diversity indicates that the coordination preferences (cis- and trans-configurations) of (R,S)-bptu play a leading role in the self-assembly of complexes: cis-bptu tends to form one-dimensional structures 1-3, while trans-bptu is easier to construct higher dimensional structures 4-5. Secondly, the different transition metal atom M(ii) adopts diverse geometry in 1-5: Cu(ii) adopts square pyramidal geometry in 1, Zn(ii) employs a tetrahedron configuration in 2, and especially in 3-5, Cd(ii) displays a trigonal bipyramidal configuration, cis-cis-trans, cis and trans octahedral configuration. Finally, the different solvent system, the coordinated/free solvent, and the secondary building units (SBUs) affect the diversification of the structure. A variable temperature magnetic susceptibility investigation manifests that antiferromagnetic interactions exist between the neighbouring metal ions in 1. Furthermore, the luminescence properties of 2-5 are investigated in the solid state at room temperature, and 4 shows highly selective and sensitive sensing for Fe3+ ions.

A green and efficient method for the synthesis of pyrroles using a deep eutectic solvent ([CholineCl][ZnCl2]3) under solvent-free sonication

A green and efficient method for Paal–Knorr pyrrole synthesis has been developed under mild conditions.