Homo- and heterometallic coordination networks based on linear trinuclear Co(ii) units: syntheses, structures and magnetic properties

Abstract

Two three-dimensional (3D) coordination networks, [Co 3 (1,4-BDC)3(L 1 )] N (L 1 ¼ N,N 0 -bis(3-pyridinyl)-1,4-benzenedicarboxamide; 1,4-H 2 BDC ¼ 1,4-benzenedicarboxylic acid), 1, and [K 2 Co 3 (L 2 ) 4 ] N (H 2 L 2 ¼ 5-acetamidoisophthalic acid), 2, have been synthesized by hydrothermal reactions and characterized by single crystal X-ray crystallography. Complex 1 consists of linear trinuclear Co(II) centers, which are linked by the 1,4-BDC À and L 1 ligands to form a rare (1 + 3) self-catenated 3D net with the new (3 6 ,4 10 ,5 11 ,6) topology, and complex 2 reveals a 3p-3d heterometallic coordination network based on linear trinuclear Co(II) and dinuclear K(I) centers bridged by the m 6 -L 2 ligands, forming a 4,4,8-connected trinodal net with the new (4 14 $6 10 $8 4 )(4 2 $6 4 )(4 4 $6 2 ) topology. The linear trinuclear Co(II) centers in 1 adopt the square pyramidal-octahedral-square pyramidal geometries, whereas those in 2 are tetrahedral-octahedral-tetrahedral. Both of the complexes exhibit paramagnetism that is consistent with the Curie-Weiss law between 60 and 300 K. The effective magnetic moments (hm eff i) of both complexes are larger than the estimated value of 6.71 m B /f.u., revealing the spin-orbit couplings that are invoked by the different distorted geometries of the linear trinuclear Co(II) centers. The dinuclear K(I) centers in 2 weaken the magnetic coupling, and reduce the antiferromagnetic ordering at 6 K.

Self-Catenated Coordination Polymers Involving Bis-pyridyl-bis-amide

“…Although the self-catenated coordination polymers have been the subject of studies during recent years, those that involve bis-pyridyl-bis-amide ligands remain scarcely reported. While {[Cu­( L 1 )­(1,4-pda)]·2H 2 O} n (1,4-H 2 pda = 1,4-phenylenediacetic acid) is the first 1D self-catenated coordination polymer, the complex [Co3­(1,4-bdc)­3­(L 3 )] n (L 3 = N,N ′-bis­(3-pyridinyl)-1,4-benzenedicarboxamide) forms a unique self-catenated 3D net with the (3 6 ·4 10 ·5 11 ·6)-8T53 topology (with catenation of 6-rings), and {[Cd 2 (1,4-bdc) 2 ( L 2 ) 2 ]·3H 2 O 3 } n exhibits self-catenated 3D net of {4 24 ·5·6 3 }- ilc topology (with self-catenation of 4-rings with four other 4-rings).…”

Metal and Ligand Effects on the Construction of Divalent Coordination Polymers Based on bis-Pyridyl-bis-amide and Polycarboxylate Ligands

“…The reagent Ni(OAc) 2 ·4H 2 O, 3,5-pyridinedicarboxylic acid, and 1,3,5-benzenetricarboxylic acid were purchased from Alfa Aesar Co. (Heysham, UK); Cu(OAc) 2 ·H 2 O and Zn(OAc) 2 ·2H 2 O from SHOWA Co. (Tokyo, Japan); Co(OAc) 2 ·4H 2 O from J. T. Baker Co. (Phillipsburg, MO, USA); and 5- tert -butylisophthalic acid from ALDRICH Co. (St. Louis, MO, USA) N , N ′-di(3-pyridyl)suberoamide ( L 1 ), N , N ′-di(3-pyridyl)adipoamide ( L 2 ), N , N ′-di(4-pyridyl)adipoamide ( L 3 ), N , N ′-bis(3-pyridinyl)terephthalamide ( L 4 ), and 5-acetamido isophthalic acid (H 2 AIPA) were prepared according to published procedures [ 5 , 9 ].…”