Syntheses, structures and magnetic properties of tetranuclear and trinuclear nickel(II) complexes with β-diketone-functionalized pyridinecarboxylate ligand

The new β-diketone-functionalized pyridinecarboxylate ligand 2-(3-oxo-3-phenyl-propionyl)-6-pyridinecarboxylic acid (H₂L) has been synthesized and fully characterized. Its tetranuclear and trinuclear nickel(II) coordination compounds [Ni₄L₄(DMF)(H₂O)₃]·2.5DMF·3H₂O (1) and [Ni₃L₂(OAc)₂(DMF)₂ (H₂O)₂]·DMF·H₂O (2) have also been synthesized and characterized by single crystal X-ray diffraction. Compound 1 has a [2 × 2] molecular grid structure and 2 is a trinuclear structure. The magnetic properties study of 1 and 2 revealed the intramolecular antiferromagnetic exchange coupling between the Ni(II) ions exists.     

The effect of reaction conditions on the nature of cadmium 1,3,5-benzenetricarboxylate metal-organic frameworks

The product from the reaction between Cd(NO₃)₂·4H₂O and 1,3,5-benzenetricarboxylic acid (H₃btc) in DMF at 95 °C depends on the reaction time, with [Cd(Hbtc)(H₂O)₂] 1 and [Cd(Hbtc)(DMF)₂] 2 isolated after heating for 10 min, the latter after standing the solution for 1-2 weeks at room temperature. [Cd₃(btc)₂(H₂O)₉]·4H₂O 3 was isolated after heating for 1 h, whereas [Cd₁₂(btc)₈(DMF)₁₄(OH₂)₂]·1.5DMF 4 was isolated after heating for 2 days. Compounds 1 and 3 have been previously reported, whereas 2 and 4 are both new. Compound 2 adopts a two-dimensional sheet structure, with the coordinated DMF ligands projecting from both sides of the sheets, whereas 4 has a complex three-dimensional structure related to the fsc net. When the reaction was repeated in the presence of pyrazine (pyz), the product [Cd(Hbtc)(pyz)(DMF)]·DMF 5 was isolated as a minor compound. Compound 5 has a two-dimensional structure, with Cd-Hbtc zig-zag chains linked into sheets through the pyrazine ligands.     

Syntheses, structures and photoluminescence properties of cadmium(II) and zinc(II) complexes with pyridinylcarboxamide-containing ligand

Four new coordination complexes [Cd(DPBA-3)₂(H₂O)₂](ClO₄)₂·2H₂O (1), [Cd(DPBA-3)(DMF)(NO₃)₂]·DMF (2), [Cd₃(DPBA-3)₂(SCN)₆]·2DMF·4H₂O (3) and [Zn(DPBA-3)(SCN)₂] (4) [DPBA-3 = N,N′-di(pyridin-3-yl)pyridine-3,5-dicarboxamide] have been synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. Complexes 1, 3 and 4 exhibit three different types of one-dimensional (1D) chain structures constructed by the metal ions and DPBA-3 ligands, and the Cd(II)-DPBA-3 1D chains in 3 are further linked by bridging SCN⁻ ligands to afford a three-dimensional (3D) framework. Complex 2 possesses a (6,3) two-dimensional (2D) layer structure. In 1-4, the hydrogen bonds involving the amide groups play important role to stabilize the resultant frameworks. The photoluminescence properties of the DPBA-3 and the complexes were studied in the solid state at room temperature.     

A series of metal-organic frameworks constructed with 2,2′-bipyridine-3,3′-dicarboxylate: Syntheses, structures, and physical properties

To determine the influence of metal ion and the auxiliary ligand on the formation of metal-organic frameworks, six new coordination polymers, {[Mn₂(bpdc)(bpy)₃(H₂O)₂] · 2ClO₄ · H₂O}_n (1), {[Mn(bpdc)(dpe)] · CH₃OH · 2H₂O}_n (2), {[Cu(bpdc)(H₂O)₂]}_n (3), {[Zn(bpdc)(H₂O)₂]}_n (4), {[Cd(bpdc)(H₂O)₃] · 2H₂O}_n (5), and {[Co(bpdc)(H₂O)₃] · 0.5dpe · H₂O}_n (6) (H₂bpdc = 2,2′-bipyridine-3,3′-dicarboxylic acid, bpy = 2,2′-bipyridine, dpe = 1,2-di(4-pyridyl) ethylene), have been synthesized and characterized. Compound 1 forms 1D helical chain structure containing two unique Mn^II ions. In 2, the bridging ligand dpe links Mn-bpdc double zigzag chains to generate a layer possesses rectangular cavities. In 3, bpdc²⁻ ligand connects to three metal centers forming a 2D network. Different from the above compounds, 4 displays a 1D double-wavelike chain. Compound 5 features a helical chain. Compound 6 also displays a helical chain with guest molecule dpe existing in the structure. These diverse structures illustrate rational adjustment of metal ions and the second ligand is a good method for the further design of helical compounds with novel structures and properties. In addition, the magnetic properties of 2, 3 and 6, the thermal stabilities and photoluminescence properties of 4 and 5 were also studied.     

Preparation, structures and properties of dinuclear and trinuclear copper(II) complexes bridged by one oximato and one hydroxo ligands

The dinuclear and trinuclear copper(II) complexes [Cu₂(L)(OH)(ClO₄)(phen)(H₂O)]ClO₄ · [Cu₂(L)(OH)(ClO₄)₂(phen)(CH₃OH)] (1) and [Cu₃(L)₂(OH)₂(H₂O)₂](NO₃)₂ (2) (HL=2-[2-(α-pyridyl)ethyl]imino-3-butanone oxime and phen=1,10-phenanthroline) were prepared and their crystal structures have been determined by X-ray crystallography. Complex 1 is composed of [Cu₂(L)(OH)(ClO₄)(phen)(H₂O)]ClO₄ (1a) and [Cu₂(L)(OH)(ClO₄)₂(phen)(CH₃OH)] (1b). In 1a and 1b, one oximato of L and one hydroxo group bridge two copper(II) ions. The linear trinuclear cation [Cu₃(L)₂(OH)₂(H₂O)₂]²⁺ in 2 is centrosymmetric, and one oximato and one hydroxo group bridge the central and terminal copper(II) ions. The strong antiferromagnetic interactions within the dinuclear and trinuclear complexes 1 and 2 have been observed (2J=∼−900 cm⁻¹ for 1 and 2, respectively, H=−2JS₁·S₂).     

Four coordination polymers constructed from a multicarboxylate ligand and metal centers various from Ba, Cu, Zn to Gd: Syntheses, crystal structures and properties

Hydrothermal reactions between H₄ODPA (2,2′,3,3′-oxydiphthalic acid) and metal ion salts of Ba²⁺, Cu²⁺, Zn²⁺ and Gd³⁺ afford four novel coordination polymers [Ba(H₂ODPA)(H₂O)₄] · H₂O (1), [Cu₂(ODPA)(H₂O)₃] · H₂O (2), Zn₂(ODPA)(H₂O)₂ (3) and [Gd(HODPA)(H₂O)_3.5] · H₂O (4), accordingly. These polymers show great differences in regard to their structures and properties originated from the variation of size and coordination geometry of the metal ions. Compound 1 presents puckered achiral layer structure with (4.8²) topology with helices, 2 has a 6³ topology with copper tetramer as SBUs, 3 has chiral layer with two kinds of helices built up from Zn-binuclear “paddle-wheel” like SBUs, and 4 features a simple 1D helix with opposite chirality. Compound 3 shows obvious fluorescent emissions upon excitation. Compound 2 shows ferromagnetic interactions between Cu^II centers bridged by carboxylate groups, whereas compound 4 presents weak ferromagnetic interaction between Gd^III ions.     

Assembly of two novel cadmium(II) supramolecular architectures constructed from pyridine-functionalized 1,10-phenanthroline ligand

Two novel cadmium(II) coordination polymers [Cd(pyip)(ox)]·H₂O (1) and [Cd₂(pyip)₂(ox)₂·(H₂O)][Cd(pyip)(ox)]·4(H₂O) (2) (pyip = 2-(pyridin-3-yl-1H-imidazo [4,5-f][1,10]phenanthroline, H₂ox = oxalic acid), have been hydrothermal synthesized and characterized by single crystal X-ray diffraction. Compound 1 is 1D zigzag chain, in which oxalate anion as bridging ligand is responsible for the formation of the main framework and pyip as chelating ligand grafts on two sides of the zigzag chain. Compound 2 contains two kinds of independent polymers [Cd₂(pyip)₂(ox)₂(H₂O)] (A) and [Cd(pyip)(ox)] (B) to form an interdigitated 1D + 1D structure, in which polymers A and B are paratactically assembled in an ABCD sequence. The fundamental unit of polymer B in 2 is the same as that in 1. For compounds 1-2, weak interactions, primarily hydrogen bonding and π?π stacking interactions, have greatly influence on the supramolecular motifs recognized in the crystal packing. Especially, the oxalate anions as bridging ligand simultaneously adopt multiform coordination modes in two compounds. In addition, 1 and 2 displayed a strong fluorescent emission in the solid state at room temperature.     

Assembly of coordination networks: Role of the different M(II)-cysteate chain in structural diversification

In this paper, we have presented the synthesis and crystal structures of five coordination polymers, namely, {[Ni₂(cysteate)₂(bpy)₂(H₂O)₂]·3H₂O}_n (1), {[Cu₂(cysteate)₂(bpy)₂(H₂O)₂]·4H₂O}_n (2), {[Mn₂(cysteate)₂(bpy)(H₂O)₄](bpy)·H₂O}_n (3), {[Zn₂(cysteate)₂(bpy)(H₂O)₄](bpy)·H₂O}_n (4), {[Cd(cysteate)(bpy)(H₂O)]·4H₂O}_n (5), using homochiral l-cysteate and 4,4′-bipyridine (bpy) as mixed ligands, reacted with Ni(II), Cu(II), Mn(II), Zn(II) and Cd(II) ions, respectively. When different metal centers being used, l-cysteate gave rise to three different architectures based on coordination polymeric chains: (1) a helical chain, which is further connected by bpy pillars to generate a racemic twofold 3D (4².8⁴)-lvt net in 1 and 2; (2) a zigzag chain, which is further linked by bpy pillars into a homochiral 2D brick-wall structure in 3 and 4; (3) a zigzag chain, which is further linked by bpy pillars into a homochiral 2D 4⁴ grid network in 5. These results indicate that the metal-directed M(II)-cysteate chain has an important effect on the structural diversification of such complexes.     

Neutral and cationic palladium(II) and platinum(II) complexes of 2,2′-dipyridylamine with saccharinate: Syntheses, spectroscopic, structural, fluorescent and thermal studies

Four palladium(II) and platinum(II) complexes of 2,2′-dipyridylamine (dpya) with saccharinate (sac), cis-[Pd(dpya)(sac)₂]·H₂O (1), cis-[Pt(dpya)(sac)₂]·H₂O (2), [Pd(dpya)₂](sac)₂·2H₂O (3) and [Pt(dpya)₂](sac)₂·2H₂O (4), have been synthesized and characterized by elemental analysis, IR, NMR, TG-DTA and X-ray diffraction. In 1 and 2, the metal ions are coordinated by two N-bonded sac ligands, and two nitrogen atoms of dpya, resulting in a neutral square-planar coordination sphere, while in 3 and 4, the metal ions are coordinated by two dpya ligands to generate square-planar cationic species, which are stabilized by two sac counter-ions. The mononuclear species of 1 and 2 interact each other through weak intermolecular N-H?O, C-H?O and π?π interactions to form a three-dimensional network, while the ions of 3 and 4 are connected by N-H?N and OW-H?O hydrogen bonds into one-dimensional chains. On heating at 250 °C, the solid cationic complexes of 3 and 4 convert to corresponding anhydrous neutral complexes of 1 and 2 after elimination of a dpya ligand. In addition, all complexes 1-4 are luminescent at room temperature and their emissions seem to be attributed to the MLCT fluorescence.     

Syntheses, crystal structures and magnetic properties of 1D and 2D cobaltous coordination polymers with mixed ligands

Two new Co(II) coordination polymers with mixed ligands, {[Co(BTA)_0.5(DBI)₂]·DBI·H₂O}_n (1) and [Co(PDA)(DBI)(H₂O)]_n (2) (H₄BTA = benzene-1,2,4,5-tetracarboxylic acid; H₂PDA = 2,2′-(1,2-phenylene)diacetic acid; DBI = 5,6-dimethyl-1H-benzoimidazole) have been synthesized under hydrothermal conditions, respectively. Both of them are characterized by elemental analyses, powder X-ray diffraction, thermogravimetric analysis, single-crystal X-ray diffraction, and magnetic susceptibilities. In 1, the Co(II) ions are four-coordinated and lie in distorted tetrahedron coordination environment. 1D ladder-like chain structure is formed by the bridging BTA⁴⁻ ligand. In 2, the Co(II) ions are in slightly distorted octahedral coordination geometry, and linked by PDA²⁻ ligand exhibiting a 2D layer structure. Temperature-dependent magnetic susceptibility measurements of 1 and 2 revealed that there are antiferromagnetic interactions between Co(II) ions.     

Synthesis and structures of three d metal coordination polymers constructed from flexible polycarboxylate and 1,10-phenanthroline ligands

Three novel d¹⁰ metal coordination polymers, {[Cd(H₂odpa)(phen)₂]·H₂O}_n (1), [Cd₂(odpa)(phen)(H₂O)₂]_n (2), {[Zn₄(odpa)₂(phen)₂(H₂O)₂]·H₂O}_n (3), (H₄odpa = 4,4′-oxydiphthalic acid, phen = 1,10-phenanthroline) were obtained with different metal/ligand ratios through hydrothermal method and characterized. Compound 1 forms a one dimensional zigzag chain, in which two phen ligands chelate to one cadmium atom. Compound 2 shows a three dimensional network structure comprised of new tetranuclear cadmium clusters as the nodes and (odpa)⁴⁻ anions as the linkers, exhibits an unusual topological structure. Compound 3 is an unprecedented three dimensional polymer based on octanuclear zinc clusters cross-linked by (odpa)⁴⁻ anions. In 1-3, central Cd^II/Zn^II ions and (odpa)⁴⁻ ligand display completely different coordination modes and conformations. In addition, the thermal stabilities and photoluminescence properties of 1-3 were also studied.     

Synthesis, structure and magnetic behavior of new 1D metal-organic coordination polymer with Fe3O core

New metal-organic coordination polymer, (Me₃NH)[Fe₃(μ₃-O)(μ-HCOO)₈]·DMF (1), was synthesized by heating of Fe(NO₃)₃·9H₂O and [NH(CH₃)₃]Cl in DMF/HCOOH solution. The single-crystal X-ray structure analysis reveals this compound has 1D anionic framework structure built from Fe₃O(μ-HCOO)₆ cluster units linked by formate bridges. Compound 1 was characterized by elemental analysis, IR and TGA. The magnetic susceptibility measurements indicate a strong antiferromagnetic exchange interaction between Fe^III ions in the cluster and intercluster magnetic interaction.     

Third-order NLO properties of the DMF solutions of 3-D network and 2-D layered organic-metal polymers with (4, 4) grid units

Reactions of 1,1′-(1,4-butanediyl)bis-1H-benzimidazole (bbbm) with Cd(II), Ni(II), or Co(II) afford three organic-metal polymers: {[Cd(bbbm)(SO₄)(H₂O)₂]CH₃OH}_n (1), {[Ni(bbbm)₂(H₂O)₂](NO₃)₂ · 2CH₃OH · 6H₂O}_n (2) and {[Co(bbbm)₂(H₂O)₂](NO₃)₂ · 2CH₃OH · 6H₂O}_n (3). In 1, bbbm and coordinate to Cd(II) simultaneously leading to a 3-D structure. In 2 and 3, each bridging bbbm ligand links two Ni(II) or Co(II) ions forming the 2-D layered structure with (4, 4) grid units. Each (4, 4) grid unit is a 44-membered ring and constructed by four bbbm ligands acting as four sides and four Ni(II) or Co(II) ions representing four corners. Their third-order nonlinear optical (NLO) properties in DMF solution have been studied by Z-scan technique. The results show that the DMF solution of 2 possesses both the large third-order NLO absorptive and strong refractive behaviors; and 3’s shows large NLO absorptive effect and weak NLO refractive behavior. A reasonably good fit between the experimental data and the theoretical curve suggests that the experimentally obtained NLO effects are effective third-order in nature.     

Synthesis, crystal structures and properties of novel zinc(II) and cadmium(II) polymeric and cyclic bimetallic complexes with fluconazole and dicarboxylate co-ligands

Four new fluconazole-bridged zinc(II) and cadmium(II) complexes with dicarboxylate co-ligands, namely [Zn(HFlu)(TPA)]_n (1), {[Cd(HFlu)₂(TPA)]·2CH₃OH}_n (2), [Zn(HFlu)₂(Suc)(H₂O)₂]·H₂O (3), and [Cd(HFlu)₂(Suc)(H₂O)₂]·H₂O (4), have been synthesized and characterized by elemental analysis, IR, TG, and single-crystal X-ray diffraction (HFlu = 2-(2,4-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol, H₂TPA = terephthalic acid, and H₂Suc = succinic acid). Complex 1 displays a 2-D corrugated network with common (4,4) topology, in which two types of grids constructed by two bridging TPA dianions and two HFlu ligands are found. Complex 2 shows an unusual (3,6) coordination layer consisting of alternative PMPM Cd-HFlu helical chains in which the Cd(II) nodes are also fixed by terephthalate dianions in a cis fashion. The isostructural complexes 3 and 4 have 20-membered dimeric macrocyclic motifs with the Zn···Zn and Cd···Cd distances of 11.258(2) and 11.528(2) Å, respectively. The fluorescence and thermal stability of complexes 1-4 have also been investigated.     

pH-value-controlled assembly of photoluminescent zinc coordination polymers

By pH-value adjustment, the reactions of zinc salt, 1,3,5-benzenetricarboxylic acid (H₃btc) and 4,4′-bipyridine (bpy) yield three coordination polymers, formulated as [Zn₃(btc)₂(bpy)(H₂O)₂]_n (1), [Zn(Hbtc)(bpy)(H₂O)]_n · 3nH₂O (2) and [Zn(Hbtc)(bpy)(H₂O)]_n · 4nH₂O (3), respectively. The structure of 1 is a 3D network containing channels filled with bpy ligands. Compound 2 consists of twofold interpenetrating (10,3)-b networks, while compound 3 is a 2D layer structure. The fluorescent studies reveal that they exhibit intense violet luminescence in solid state.     

Two new supermolecular structures of organic-inorganic hybrid compounds: [Zn(phen)(SO4)(H2O)2]n and [Cu(phen)(H2O)2] · SO4 (phen = 1,10-phenanthroline)

Two new organic-inorganic hybrid compounds [Zn(phen)(SO₄)(H₂O)₂]_n (1) and [Cu(phen)(H₂O)₂] · SO₄ (2) have been prepared by conventional aqueous solution synthesis and characterized by single-crystal X-ray diffraction, IR spectroscopy, thermal gravimetric analysis (TGA) and fluorescent spectroscopy. In compound 1, the sulfate group adopts bidentate mode to coordinate with two Zn(II) ions to form one-dimensional polymer. The one-dimensional polymers are further linked together via the intermolecular hydrogen-bonding and π-π stacking interactions to form a 3D supramolecular framework. Compound 2 is build up of discrete [Cu(phen)(H₂O]²⁺ cations and SO₄²⁻ anions to form a three-dimensional framework via hydrogen-bonding and π-π stacking interactions. Furthermore, the luminescent properties of both 1 and 2 were studied. The complexes 1 and 2 excited at 280 nm wavelength produced characteristic luminescence features, arising maybe due to the π-π transitions.     

Crystal structures and luminescent properties of zinc(II) and cadmium(II) compounds constructed from 5-sulfoisophthalic acid and flexible bis-triazole ligands

Four new cadmium(II) and zinc(II) coordination polymers {[Zn(btrp)(SIP)][Zn_0.5(H₂O)₃]}_n (1), {[Cd_1.5(btrp)(SIP)(H₂O)₂]·2H₂O}_n (2), {[Cd_1.5(btrb)(SIP)(H₂O)₃]·2H₂O}_n (3), {[Zn_1.5(btrb)_1.5(SIP)(H₂O)₂]·2H₂O}_n (4) (btrp = 1,3-bis(1,2,4-triazol-1-yl)propane, btrb = 1,3-bis(1,2,4-triazol-1-yl)butane, NaH₂SIP = 5-sulfoisophthalic acid monosodium salt) have been synthesized under hydrothermal conditions and structurally characterized. Compound 1 possesses an infinite 1D ladder-like chain structure with [Zn(H₂O)₆]²⁺ trapped in the pores, which is further interconnected by π?π interactions to lead to a 2D supramolecular architecture. Compounds 2 and 3 features two similar 2D layer structures, and the resulting 2D structures are interconnected by hydrogen-bond interactions to lead to 3D supramolecular architectures. Compound 4 is a 2D parallel ladder structure, and through the interpenetrating btrb ligand, it constructs into 3D architectures. Luminescence analyses were performed on all the four compounds, which show strong fluorescent emissions in the solid state at room temperature.     

Platinum(II) and palladium(II) saccharinato complexes with 2,2′:6′,2″-terpyridine: Synthesis, characterization, crystal structures, photoluminescence and thermal studies

[Pd(sac)(terpy)](sac)·4H₂O (1), [Pt(sac)(terpy)](sac)·5H₂O (2), [PdCl(terpy)](sac)·2H₂O (3) and [PtCl(terpy)](sac)·2H₂O (4) (sac = saccharinate, and terpy = 2,2′:6′,2″-terpyridine) have been synthesized and characterized by elemental analysis, FT-IR, ¹H NMR and ¹³C NMR. In 1 and 2, a tridentate terpy ligand together with an N-coordinated sac ligand form the square-planar geometry around the palladium(II) or platinum(II) ions, while one sac anion remains outside the coordination sphere as a counter-ion. X-ray single crystal studies show that the [M(sac)(terpy)]⁺ ions in 1 and 2 reside in the centers of a hydrogen bonded honeycomb network formed by the uncoordinated sac ions and the lattice water molecules. Complexes 3 and 4 are isostructural and consist of a [M(Cl)(terpy)]⁺ cation, a sac anion and two lattice water molecules. The [M(Cl)(terpy)]⁺ ions interact with each other via M-M and π-π stacking interactions and these π interacted units are assembled to a 2D network by water bridges involving the sac ions and lattice water molecules. Convenient synthetic paths for 1-4 are also presented, and spectral, luminescence and thermal properties were discussed.     

Synthesis, structures, and magnetic properties of dicopper(II) and dinickel(II) complexes with a new bis(macrocycle), 7,7-(2-hydoxypropane-1,3-diyl)bis{3,7,11,17-tetraazabicyclo[11.3.1]- heptadeca-1(17),13,15-triene}

A new bis(macrocycle) ligand, 7,7^′-(2-hydoxypropane-1,3-diyl)-bis{3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene} (HL), and its dicopper(II) ([Cu₂(HL)Cl₂](NO₃)₂ · 4H₂O (4a), [Cu₂(HL)I₂]I₂ · H₂O (4b)) and dinickel(II) ([Ni₂(L)(OH₂)](ClO₄)₃ (5a), [Ni₂(L)(OH₂)]I₃ · 2H₂O (5b), [Ni₂(L)N₃](N₃)₂ · 7H₂O (5c)) complexes have been synthesized. The alkoxide bridged face-to-face structure of the dinickel(II) complex 5c has been revealed by X-ray crystallography, as well as the “half-opened clamshell” form of the bis(macrocyclic) dicopper(II) complex 4b. Variable temperature magnetic susceptibility studies have indicated that there exists intramolecular antiferromagnetic coupling (J=−33.8 cm⁻¹ (5a), −32.5 cm⁻¹ (5b), and −29.7 cm⁻¹ (5c)) between the two nickel(II) ions in the nickel(II) complexes.     

Temperature effect on the conversions of phthalato and maleato manganese(II) complexes with diamine ligands

1,10-Phenanthroline hydrogen phthalato manganese(II) dimer [Mn₂(Hphth)₂(phen)₄] · 2Hphth · 6H₂O (1), monomeric phenanthroline phthalato manganese(II) monomer [Mn(phth)(phen)₂(H₂O)] · 2.5H₂O (2), 2,2′-bipyridine phthalato manganese(II) polymer [Mn(phth)(bpy)(H₂O)₂]_n (3) and 1,10-phenanthroline maleato polymer [Mn(male)(phen)(H₂O)₂]_n · 2nH₂O (4) (H₂phth = o-phthalic acid, male = maleic acid, phen = 1,10-phenanthroline and bpy = 2,2′-bipyridine) have been synthesized and characterized spectroscopically and structurally. Each Mn(II) atom in dimeric 1 is octahedrally coordinated by two oxygen atoms of phthalate anions and by two cis-phenanthroline ligands. The hydrogen phthalato anion bridges the Mn(II) ions through the deprotonated carboxyl groups, while the carboxylic acid group remains free. In the monomeric 2, the Mn(II) ion is octahedrally surrounded by four nitrogen atoms from two cis-phen ligands, one carboxyl oxygen from a monodentate phth ion, and one coordinated water molecule. The dimeric phthalato complex 1 can be cleaved into monomer 2 under heating with deprotonation, and the course of the reaction can be qualitatively traced by IR spectra. The phthalate group in the complex 3 binds to two manganese atoms through the vicinal carboxyl-oxygen atoms in syn-syn bridging mode. The Mn(II) atoms are linked by the phthalate group to yield a one-dimensional chain running along the a-axis. The coordination polymer 3 can be obtained from the reaction of dichloro dibipyridine manganese with phthalate under heating. In polymer 4, the manganese atom is six-coordinated by two nitrogen atoms from phen, two oxygen atoms from the coordinated water molecules and two oxygen atoms from two different maleate dianions. Each maleato unit links two neighboring manganese atoms to yield one-dimensional chain along b-axis in bis-monodentate mode. The single-chain polymer 4 prepared at low temperature can be converted to double-chain coordination polymer [Mn(male)(phen)]_n · nH₂O (5) with dehydration in warm solution.