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Diverse Structures and Magnetism of Cobalt(II) and Manganese(II) Compounds with Mixed Azido and Carboxylato Bridges Induced by Methylpyridinium Carboxylates
Author(s) -
Jia QinXiang,
Tian Hua,
Zhang JianYong,
Gao EnQing
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201001151
Subject(s) - carboxylate , antiferromagnetism , manganese , chemistry , crystallography , ferromagnetism , metamagnetism , magnetism , cobalt , spin canting , stereochemistry , inorganic chemistry , magnetization , magnetic field , condensed matter physics , physics , organic chemistry , quantum mechanics
Herein we present a systematic study of the structures and magnetic properties of six coordination compounds with mixed azide and zwitterionic carboxylate ligands, [M(N 3 ) 2 (2‐mpc)] (2‐mpc= N ‐methylpyridinium‐2‐carboxylate; M=Co for 1 and Mn for 2 ), [M(N 3 ) 2 (4‐mpc)] (4‐mpc= N ‐methylpyridinium‐4‐carboxylate; M=Co for 3 and Mn for 4 ), [Co 3 (N 3 ) 6 (3‐mpc) 2 (CH 3 OH) 2 ] ( 5 ), and [Mn 3 (N 3 ) 6 (3‐mpc) 2 ] ( 6 ; 3‐mpc= N ‐methylpyridinium‐3‐carboxylate). Compounds 1 – 3 consist of one‐dimensional uniform chains with (μ‐EO‐N 3 ) 2 (μ‐COO) triple bridges (EO=end‐on); 5 is also a chain compound but with alternating [(μ‐EO‐N 3 ) 2 (μ‐COO)] triple and [(EO‐N 3 ) 2 ] double bridges; Compound 4 contains two‐dimensional layers with alternating [(μ‐EO‐N 3 ) 2 (μ‐COO)] triple, [(μ‐EO‐N 3 )(μ‐COO)] double, and (EE‐N 3 ) single bridges (EE=end‐to‐end); 6 is a layer compound in which chains similar to those in 5 are cross‐linked by a μ 3 ‐1,1,3‐N 3 azido group. Magnetically, the three Co II compounds ( 1 , 3 , and 5 ) all exhibit intrachain ferromagnetic interactions but show distinct bulk properties: 1 displays relaxation dynamics at very low temperature, 3 is an antiferromagnet with field‐induced metamagnetism due to weak antiferromagnetic interchain interactions, and 5 behaves as a noninnocent single‐chain magnet influenced by weak antiferromagnetic interchain interactions. The magnetic differences can be related to the interchain interactions through π–π stacking influenced by different substitution positions in the ligands and/or different magnitudes of intrachain coupling. All of the Mn II compounds show overall intrachain/intralayer antiferromagnetic interactions. Compound 2 shows the usual one‐dimensional antiferromagnetism, whereas 4 and 6 exhibit different weak ferromagnetism due to spin canting below 13.8 and 4.6 K, respectively.