Rui-Xiang Hu

Syntheses and crystal structures of cis - and trans -copper(II) complexes of L-arginine

Two copper(II) complexes of L-arginine, trans-[Cu(l-Arg)2(NO3)]NO3 · 3H2O (1) and {cis-[Cu(l-Arg)2](NO3)2 · 3H2O} n (2) (Arg = arginine) were prepared by reaction of Cu(NO3)2 · 3H2O and L-arginine in acetone and aqueous solution, respectively. X-ray analysis reveals 1 crystallizes in a monoclinic system, P21 with a = 10.3857(15), b = 16.885(3), c = 15.9586(19) Å, β = 15.9586(19)°, Z = 4, V = 2654.2(6) Å3. The copper(II) centers lie in a distorted N2O3 square-pyramidal environment. While 1 adopts a mononuclear structure, and the axial position occupied by a nitrate with Cu1–O9 = 2.535 Å and Cu2–O20 = 2.581 Å, 2 features a 1-D infinite chain structure. In 1, adjacent monomeric units connect with each other to give a 2-D layer structure of (4, 4) nets through hydrogen bonds between the guanidinium and carboxylic groups of arginine, and 2-D layers further assemble to a 3-D supermolecular structure via a series of inter-layer hydrogen bonds.

Structure and Magnetic Properties of a Three-dimensional Cobalt Metal-Organic Framework

A new 3D fourfold interpenetrated metal-organic framework, [Co(L)2(SO4)]・H2O (1), has been synthesized by the solvothermal reaction of L with CoSO4・6H2O (L = 1,4-bis(imidazolyl)benzene). Compound 1 crystallizes in the monoclinic space group P21/n, with the cell parameters: a = 9.943(2), b = 21.7104(15), c = 13.2658(18) Å , β = 97.638(3)◦, V = 2838.2(8) Å3, R1 = 0.0566 and wR2 = 0.1035. It represents a novel dia net, in which the cobalt atoms are alternately bridged by the imidazolyl N atoms of the ligands L into a three-dimensional network. Compound 1 displays antiferromagnetic interactions. From 2 to 300 K, χm −1 it obeys the Curie-Weiss law with C =2.68 emu K mol−1 and Θ = −2.59 K Graphical Abstract Structure and Magnetic Properties of a Three-dimensional Cobalt Metal-Organic Framework

Poly[[cobalt(II)-di-μ3-3,5-diamino-benzoato-κ3N:N':O] monohydrate]

In the title compound, ([Co(C 7 H 7 N 2 O 2 ) 2 ].H 2 O} n , the Co atom lies on an inversion centre and has octahedral geometry, defined by two O atoms in axial positions and four N atoms in equatorial sites from six different 3,5-diaminobenzoate ligands. Each 3,5-diaminobenzoate anion acts as a μ 3 -bridging ligand, linking three adjacent Co ions through one O atom and two N atoms to form a three-dimensional coordination polymer.