Synthesis,Structure and Magnetic Properties of Two Cobalt(II) Dicyanamide (dca) Complexes with Heterocyclic Nitrogen Donors Tetra(2‐pyridyl)pyrazine (tppz) and 2,4,6‐Tri(2‐pyridyl)‐1,3,5‐triazine (tptz): [Co2(tppz)(dca)4]·CH3CN and [Co(tptz)(dca)(H2O)](dca) |
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Authors: | Jun Luo Lijuan Qiu Baoshu Liu Xinrong Zhang Feng Yang Lili Cui |
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Affiliation: | School of Pharmacy, Second Military Medical University of PLA, Shanghai 200433, China |
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Abstract: | Two new transition metal dicyanamide complexes [Co2(tppz)(dca)4]·CH3CN ( 1 ) [tppz=tetra(2‐pyridyl)pyrazine, dca=dicyanamide] and [Co(tptz)(dca)(H2O)](dca) ( 2 ) [tptz=2,4,6‐tri(2‐pyridyl)‐1,3,5‐triazine] were synthesized and characterized by single crystal X‐ray diffraction analysis. In 1 each cobalt(II) atom is coordinated to three dca anions and one tppz molecule to form a distorted octahedral geometry, the neigbour two cobalt(II) atoms are bridged by one tppz ligand to form a dimer, then the cobalt(II) atoms in each dimer are joined together to form a ladder chain structure. In 2 the coordination geometry around the central metal is also distorted octahedral, each cobalt(II) atom is coordinated by two dca anions, one tptz molecule and one water ligand to form a cationic part, and the cationic part is linked with the free dca anions via the electrostatic attraction to give an infinite chain structure. Magnetic susceptibility measurement in the range of 2–300 K indicates that there are antiferromagnetic couplings between adjacent metal ions in 1 (T>29 K, (=?9.78 K, C=4.92 cm3·K·mol?1) and ferromagnetic couplings in 2 (T>150 K, (=7.97 K, C=2.59 cm3·K·mol?1) respectively. |
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Keywords: | dicyanamide tetra(2‐pyridyl)pyrazine 2,4,6‐tri(2‐pyridyl)‐1,3,5‐triazine cobat(II) complex crystal structure magnetic property |
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