Coordination polymer

About: Coordination polymer is a research topic. Over the lifetime, 11988 publications have been published within this topic receiving 212219 citations.

Benzoate acid-dependent formation of a series of interpenetrating metal–organic frameworks based on the cobalt∩1,4-bis(imidazolyl)benzene coordination substrate

Abstract: In this work, three structurally related aromatic polycarboxylic acids, 1,4-benzenedicarboxylic acid (H2bdc), 1,3,5-benzenetricarboxylic acid (H3btc), and 1,2,4,5-benzenetetracarboxylic acid (H4bttc), have been utilized as the ancillary ligands to perform a systematic study on the structure diversity of coordination polymer based on the Cobalt∩1,4-bis(imidazolyl)benzene matrix. The solvothermal reactions of Co(NO3)2 with the aromatic acids and bib ligand afford three novel coordination polymers, [Co(bib)(bdc)]∞ (1), {[Co3(btc)2(bib)2(H2O)2](H2O)2}∞ (2), and {[Co2(bttc)(bib)2](H2O)2}∞ (3). Compounds 1–3 illustrate a series of interpenetrating networks built up of different benzoate-bridging 1D chains. Owing to the different situation of the carboxylic group, the benzoates adopt bidentate linear, tridentate T-shaped and tetradentate double-track bridging modes to link metal centers into a W-type chain, ladder and double-center chain, respectively. These chains are further decorated by bib rods to afford a parallel interpenetrating (4,4) sheet for 1, and two three-fold interpenetrating α-Po networks based on different units for 2 and 3. The variety of structures and topologies indicates that aromatic acids play essential roles in the assembly of the final frameworks.

Ferromagnetic Coupling in a 1D Coordination Polymer Containing a Symmetric [Cu(μ1,1-N3)2Cu(μ1,1-N3)2Cu]2+ Core and Based on an Organic Ligand Obtained from the Solid State

Abstract: Addition of rctt-tetrakis(2-pyridyl)cyclobutane (2,2'-tpcb) in a Cu(II)/N(3)- solution afforded the 1D coordination polymer [Cu(3)(N(3))(6)(2,2'-tpcb)(DMF)(2)](n) (1). The ligand 2,2'-tpcb serves as a tetradentate bis-chelating ligand by linking linear [(DMF)Cu(mu(1,1)-N(3))(2)Cu(N(3))(2)(mu(1,1)-N(3))(2)Cu(DMF)] trinuclear units to produce a zigzag chain. Within each centrosymmetric trinuclear unit there exist two irregularly asymmetric end-on double azido-bridged [Cu(mu(1,1)-N(3))(2)Cu](2+) cores, while one of the largest Cu-Nazide-Cu angles is observed. Magnetic susceptibility data, measured from 2 to 300 K, show bulk moderate ferromagnetic coupling within the magnetically isolated trinuclear units. These data were fitted to the appropriate equation derived from the Hamiltonian H = -J(1)(S(A1)S(B) + S(A2)S(B)) - J(2)S(A1)S(A2), giving the parameters J1 = +70(3) cm(-1), J2 = -3(2) cm(-1), g = 2.12(1), with an intertrimer interaction parameter theta = -0.74(2) K. The coupling constants were correlated with the structural parameters. Density functional calculations reproduce very well the experimental J values and show that ferromagnetism for this complex is mainly due to the topology of the magnetic orbitals and the different coordination spheres of two neighboring Cu(II) atoms, resulting in a small overlap of the orbitals possessing the unpaired electrons.

Influence of the co-ligand on the magnetic and relaxation properties of layered cobalt(II) thiocyanato coordination polymers.

Abstract: Reaction of Co(NCS)2 with 1,2-bis(4-pyridyl)-ethane (bpa) leads to the formation of [Co(NCS)2(bpa)2]n, which, on heating, transforms into the new layered coordination polymer [Co(NCS)2(bpa)]n. This compound can also be prepared in solution, but because no reasonable single crystals are available, its crystal structure was determined from X-ray powder data from scratch. In the crystal structure of [Co(NCS)2(bpa)]n, the cobalt(II) cations are coordinated by two S-bonded and two N-bonded thiocyanato anions and two N atoms of the bpa co-ligands in a distorted octahedral geometry. The cobalt(II) cations are linked into chains by pairs of μ-1,3 bridging thiocyanato anions. These chains are further connected into layers by the 1,2-bis(4-pyridyl)-ethane ligand. The compound was magnetically characterized, and, for comparative purposes, the complementary magnetic study of a known and very similar compound, [Co(NCS)2(bpe)]n (bpe = 1,2-bis(4-pyridyl)-ethylene), was also undertaken. The compounds differ in their inte...

Quantification of Ultrasound‐Induced Chain Scission in PdII–Phosphine Coordination Polymers

Abstract: A kinetically inert, reversible coordination polymer (3) was obtained through complexation of dicyclohexylphosphine telechelic poly(tetrahydrofuran) with palladium(II) dichloride. This coordination polymer is unreactive towards palladium(II) dichloride bis(1-diphenylphosphino)dodecane (4), because ligand dissociation in the coordination polymer is slow. However, upon ultrasonication of solutions of 3 in toluene in the presence of 4, formation of palladium(II) heterocomplexes was observed with 31P NMR spectroscopy. Heterocomplex formation, the consumption of 4, and changes in molecular weight were used to quantify the scission process. In the presence of 60 equivalents of the alkyldiphenylphosphine stopper complex, the reduction in molecular weight was strongly enhanced; over a period of eight hours the weight-averaged molecular weight was reduced from 1.1×105 to 2.3×104 g mol−1 while 47 % of the palladium(II) complexes in the coordination polymer had been converted into heterocomplexes. These results show that the system of 3 in combination with scavenger 4 is a suitable system to study the efficiency of ultrasound-induced chain scission of coordination polymers.