Synthesis and Characterization of Three New Zipper‐like Lanthanide [Ln = TmIII,NdIII, CeIII] Coordination Polymers Containing 1,3‐Benzenedicarboxylate and 2‐Phenyl‐1H‐1,3,7,8‐tetraazacyclopenta[l]phenanthrene Ligands

Reaction of the ligands 2‐phenyl‐1H‐1,3,7,8‐tetraazacyclopenta[l]phenanthrene (PTCP) and benzene‐1,3‐dicarboxylic acid (m‐H₂BDC) with Ln₂O₃ under hydrothermal conditions lead to three isomorphous coordination polymers [Ln₂(PTCP)₂(m‐BDC)₃·H₂O]_n (Ln = Tm, 1 ; Nd, 2 ; Ce, 3 ). The coordination polymers crystallize in monoclinic, space group P2₁/m with a = 9.8340(2), b = 17.9140(4), c = 15.6050(3) Å, β = 100.51(3)° for 1 , with a = 9.8423(3), b = 18.3562(4), c = 15.6209(3) Å, β = 102.138(3)° for 2 , and with a = 9.8620(2), b = 18.4960(4), c = 15.6530(3) Å, β = 102.42(3)° for 3 , respectively. The metal ions (Ln³⁺) are located in an octacoordinated environment and the dinuclear [Ln₂O₁₂N₄] units act as octahedral secondary building units (SBU), which are bridged in two coordination modes by six m‐BDC ligands to form a three‐strand‐like chain. These chains are decorated by PTCP ligands and form unique three zipper‐like structures, which are further assembled into three‐dimensional supramolecular nets by π ··· π stacking interactions. Additionally, hydrogen bonds are observed in the structures. Furthermore, compounds 1 – 3 were studied by IR spectrocopy and thermogravimetric analyses.     

Crystal Structure of the [(C5H4BMe2)2Fe]‐4,4′‐bipyridine Polymer from High Resolution X‐Ray Powder Diffraction

The crystal structure of [(C₅H₄BMe₂)₂Fe]‐4,4′‐bipyridine [ 2 · bipy]_n has been determined by the method of simulated annealing from high resolution X‐ray powder diffraction at room temperature. The compound is of interest, because it proves that highly ordered organometallic macromolecules can be formed in the solid state via the self‐assembly of N–B‐donor‐acceptor bonds. [ 2 · bipy]_n crystallizes in the triclinic space group, P 1, Z = 2, with unit cell parameters of a = 8.3366(2) Å, b = 11.4378(3) Å, c = 12.6740(5) Å, α = 112.065(2)°, β = 108.979(1)°, γ = 90.551(2)°, and V = 1047.06(6) ų. For the structure solution of [ 2 · bipy]_n 11 degrees of freedom (3 translational, 3 orientational, 5 torsion angles) were determined within several hours, demonstrating that the crystal packing and the molecular conformation of medium sized (< 50 non‐hydrogen atoms) coordination compounds can nowadays be solved routinely from high resolution powder diffraction data.     

The Structural Systematics of Protonation of Some Important Nitrogen‐base Ligands. I Some Univalent Anion Salts of Doubly Protonated 2, 2′:6′, 2″‐Terpyridyl

A number of salts of 2,2′:6′,2″ ‐terpyridyl (‘tpy’) with univalent anions (halides : X = Cl, Br, I; oxyanions of increasing basicity: ClO₄, NO₃, ‘tfa’ = trifluoroacetate, ‘tca’ = trichloroacetate), variously solvated, have been structurally characterized by single crystal X‐ray studies. In all cases the tpy moieties are found to be doubly protonated [tpyH₂]²⁺, the hydrogen atoms being associated with the nitrogen atoms of the peripheral rings, these together with the central nitrogen atom being directed towards a common focus, in most cases ‘chelating’ one of the counter‐ion components in diverse ways. Thus the chloride and bromide compounds are isomorphous [(tpyH₂)X]⁺X⁻·H₂O arrays; a second dihydrate phase is also described for the chloride, the two forms having the unchelated anion and water molecules engaged in hydrogen‐bonded networks essentially independent of [(tpyH₂)X]⁺. The iodide is anhydrous, and of a different structural type, the anions, presumably too large for chelation, lying out of plane to either side, and linking different cations into a one‐dimensional polymer; in the perchlorate, the unsolvated aggregate is now discrete [(tpyH₂)X₂], a pair of perchlorate ions disposed to either side of the tpy plane, lying each with one oxygen atom interacting with both of the two protonating hydrogen atoms. In the anhydrous X = NO₃, tfa, tca arrays, the lattices are solvated by the parent acids; one oxygen atom of each anion is chelated by the [tpyH₂]²⁺ as in the chlorides, the other anion, with the acid, forming an independent ‘acid salt’ counterion [XHX]⁻ in each case, retaining the additional protonic hydrogen rather than further protonating the central ring, all being of the form [(tpyH₂)X]X·HX = [(tpyH₂)X][X(HX)].     

Poly­[[[(1,10‐phenanthroline‐κ2N,N′)­zinc(II)]‐μ3‐5‐hydroxy­isophthalato‐κ4O,O′:O′′:O′′′] monohydrate]

In the title compound, {[Zn(C₈H₄O₅)(C₁₂H₈N₂)]·H₂O}_n or {[Zn(OH‐BDC)(phen)]·H₂O}_n (where OH‐H₂BDC is 5‐hydroxy­isophthalic acid and phen is 1,10‐phenanthroline), the Zn atoms are coordinated by two N atoms from the phen ligands and by four O atoms from hydroxy­isophthalate ligands in a highly distorted octahedral geometry, with Zn—O distances in the range 2.042 (4)–2.085 (5) Å and Zn—N distances of 2.133 (5) and 2.137 (5) Å. The {[Zn(OH‐BDC)(phen)]·H₂O}_n infinite zigzag polymer forms a helical chain of [Zn₂(OH‐BDC)₂]_n units. Face‐to‐face π–π interactions (3.60–3.75 Å) occur between two phen rings belonging to the same helical chain. Consolidation of the packing structure is achieved by O—H⋯O hydrogen‐bonding interactions between the carboxyl­ate O atoms, the hydroxyl group and the water mol­ecule, forming two‐dimensional sheets.     

Synthesis,Structures, Fluorescence Properties,and Natural Bond Orbital (NBO) Analysis of Two Metal [EuIII,CoII] Coordination Polymers Containing 1, 3‐Benzenedicarboxylate and 2‐(4‐methoxyphenyl)‐1H‐imidazo[4, 5‐f][1, 10]phenanthroline Ligands

Two new metal‐organic coordination polymers[Eu(m‐BDC)_1.5(MOPIP) · 1/2H₂O]_n ( 1 ) and [Co(m‐BDC)(MOPIP)₂ · 2H₂O]_n ( 2 ) [m‐H₂BDC = benzene‐1, 3‐dicarboxylic acid, MOPIP = 2‐(4‐methoxyphenyl)‐1H‐imidazo[4, 5‐f] 1 , 10 phenanthroline] were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. The coordination polymers crystallize in monoclinic space group P2₁/m for 1 ( 2 : P2₁/n), with a = 9.779(2), b = 18.242(4), c = 17.146(3) Å, β = 106.41(3)° for 1 , and with a = 8.2153(16), b = 27.974(6), c = 17.974(4) Å, β = 100.40(3)° for 2 . The crystal structure of complex 1 is a zipper‐like chain of octacoordinate Eu³⁺ ions, in which Eu³⁺ ions are bridged in two coordination modes by m‐BDC²⁺ ligands and decorated by MOPIP ligands. The molecular structure of complex 2 consists of a hexacoordinte Co²⁺ atom, which generates a slightly distorted octahedral arrangement, and assembles into three‐dimensional supramolecular nets by π ··· π stacking interactions. Additionally, these two compounds show strong fluorescence in the solid state at room temperature. Natural bond orbital (NBO) analysis is performed by using the NBO method built in Gaussian 03 Program. The calculation results show a weak covalent interaction between the coordinated atoms and metal ions.     

Syntheses,Crystal Structures,and Fluorescence Properties of Two Transition Metal‐Organic Coordination Polymers Based on 4,4′‐Dimethyl‐2,2′‐bipyridine

Two transition metal‐organic coordination polymers, [Mn₂(1,3‐bdc)₂(Me₂bpy)₂] · Me₂bpy ( 1 ) and [Co(4,4′‐oba)(Me₂bpy)] ( 2 ) were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, TG, and single‐crystal X‐ray diffraction [1,3‐H₂bdc = benzene‐1,3‐dicarboxylic acid, H₂oba = 4,4′‐oxybis(benzoic acid) Me₂bpy = 4,4′‐dimethyl‐2,2′‐bipyridine]. Compound 1 crystallizes in the orthorhombic system, space group P2₁2₁2₁, with a = 23.371(5), b = 14.419(3), and c = 14.251(3) Å. Compound 2 crystallizes in the monoclinic system, space group P2₁/c, with a = 7.4863(15), b = 18.272(4), c = 16.953(5) Å, and β = 107.44(3)°. The crystal structure of complex 1 is a wave‐like layer with central Mn²⁺ atoms bridged by 1,3‐bdc ligands, whereas the structure of compound 2 presents a ladder chain of hexacoordinate Co²⁺ atoms, in which the metal atoms are bridged by 4,4′‐oba ligands and decorated by Me₂bpy ligands. The two compounds are further extended into 3D supramolecular structures through π–π stacking interactions. Additionally, the compounds show intense fluorescence in solid state at room temperature.     

Three Ternary Rare Earth(III) Complexes Based on 3‐[(4,6‐Dimethyl‐2‐pyrimidinyl)thio]‐propanoic Acid and 1,10‐Phenanthroline: Synthesis,Crystal Structure and Antioxidant Activity

Three ternary rare earth [Nd^III ( 1 ), Sm^III ( 2 ) and Y^III ( 3 )] complexes based on 3‐[(4,6‐dimethyl‐2‐pyrimidinyl)thio]‐propanoic acid (HL) and 1,10‐phenanthroline (Phen) were synthesized and characterized by IR and UV/Vis spectroscopy, TGA, and single‐crystal X‐ray diffraction. The crystal structures showed that complexes 1 – 3 contain dinuclear rare earth units bridged by four propionate groups and are of general formula [REL₃(Phen)]₂ · nH₂O (for 1 and 2 : n = 2; for 3 : n = 0). All rare earth ions are nine‐coordinate with distorted mono‐capped square antiprismatic coordination polyhedra. Complex 1 crystallizes in the monoclinic system, space group P2₁/c with a = 16.241(7) Å, b = 16.095(7) Å, c = 19.169(6) Å, β = 121.48(2)°. Complex 2 crystallizes in the monoclinic system, space group P2₁/c with a = 16.187(5) Å, b = 16.045(4) Å, c = 19.001(4) Å, β = 120.956(18)°. Complex 3 crystallizes in the triclinic system, space group P1 with a = 11.390(6) Å, b = 13.636(6) Å, c = 15.958(7) Å, α = 72.310(17)°, β = 77.548(15)°, γ = 78.288(16)°. The antioxidant activity test shows that all complexes own higher antioxidant activity than free ligands.     

Metal Derivatives of 1,3‐Imidazolidine‐2‐thione with Divalent d10 Metal Ions (Zn–Hg) : Synthesis and Structures

Reactions of divalent Zn‐Hg metal ions with 1,3‐imidazolidine‐2‐thione (imdtH₂) in 1 : 2 molar ratio have formed monomeric complexes, [Zn(η¹‐S‐imdtH₂)₂(OAc)₂] ( 1 ), [Cd((η¹‐SimdtH₂)₂I₂] ( 2 ), [Cd(η¹‐S‐imdtH₂)₂Br₂] ( 3 ), and [Hg(η¹‐S‐imdtH₂)₂I₂] ( 4 ). Complexes 1 – 4 , have been characterized by elemental analysis (C, H, N), spectroscopy (IR, ¹H, NMR) and x‐ray crystallography ( 1 ‐ 4 ). Hydrogen bonding between oxygen of acetate and imino hydrogen of ligand, {N(2)–H(2C)···O(2)^#} in 1 , ring CH and imino hydrogen, {C(2A)–H(2A)···Br(2)^#} in 3 have formed H‐bonded dimers. Similarly, the interactions between molecular units of complexes 2 and 4 have yielded 2D polymers. The polymerization occurs via intermolecular interactions between thione sulfur and imino hydrogen, {N(2)–H(2)···S(1)^#}, imino hydrogen and the iodine atom, {NH(1)···I(2)^#} in 2 and imino hydrogen – iodine atom {N(2A)–H(2A)···I(2)} and I···I interaction in 4 . Crystal data: [Zn(η¹‐S‐imdtH₂)₂(OAc)₂] ( 1 ), C₁₀H₁₈N₄O₄S₂Zn, orthorhombic, Pbcn, a = 9.3854(7) Å, b = 12.4647(10) Å, c = 13.2263(11) Å; V = 1547.3(2) ų, Z = 4, R = 0.0280 [Cd((η¹‐S‐imdtH₂)₂I₂] ( 2 ), C₆H₁₂CdI₂N₄S₂, orthorhombic, Pnma, a = 13.8487(10) Å, b = 14.4232(11) Å, c = 7.0659(5) Å; Z = 4, V = 1411.36(18) ų, R = 0.0186.     

Synthesis,Structure, and Properties of a New Calcium(II) Complex of 1,10‐Phenanthroline, 1,2,4,5‐Benzenetetracarboxylic Acid,and a New Precursor to Produce Pure Phase Micro‐crystalline Calcite Particles

The self‐assembly of 1, 0‐phenanthroline (phen) and 1,2,4,5‐benzenetetracarboxylic acid(H₄btc) with Ca(NO₃)₂ gives rise to a two‐dimensional network structure coordination polymer, [Ca(phen)(btc)_0.5(H₂O)] ( 1 ), which was characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. This compound is monoclinic, space group C2/c, with Z = 8 in a unit cell with dimensions a = 21.744(3) Å, b = 10.0151(12) Å, c = 14.7122(17) Å, β = 110.2850(10)°. The structure contains one crystallographic unique Ca^II atom, one phen coordinated molecule and a half of btc^4– anion. The phen molecule acts as a didentate ligand chelating with a Ca^II atom, whereas the btc^4– anion acts as a μ₆‐bridge linking six different Ca^II atoms to form a two‐dimensional network with (4, 4) topological structure. The three dimensional stacking structures are formed by C–H ··· O hydrogen bonding and π–π interaction. The thermal stability and fluorescent properties of 1 were investigated. Calcite particles are produced by calcination of compound 1 at 580 °C. The obtained calcite was characterized by XRD and SEM analyses.     

Hydrothermal Synthesis and Crystal Structure of a New Oxalato‐bridged Lead(II) Polymer: {[Pb(phen)2(ox)]·5H20}n (phen = 1, 10‐phenanthroline,ox = oxalate)

A new one‐dimensionally neutral coordination polymer, namely {[Pb(phen)₂(ox)]·5H₂0}_n (phen = 1, 10‐phenanthroline, ox = oxalate) ( 1 ), has been synthesized under hydrothermal condition and characterized by X‐ray crystallography. Complex 1 crystallizes in the orthorhombic space group Pban (No. 50) with a = 19.358(2), b = 6.8135(6), c = 9.7015(8)Å, V = 1279.6(2)ų, and Z = 2. Each Pb(II) atom is eight‐coordinated in a square‐antiprismatic D_4d geometry by four nitrogen atoms from two phen groups and four oxygen atoms from two ox ligands. The polymeric chains further constructed into a three‐dimensional network via strong π—π stacking interactions and hydrogen bonds. The complex exhibits intense blue photoluminescence with an emission maximum at 403 nm at room temperature.     

Crystal Structures and Solution Studies of Two Novel Zinc(II) Complexes of a Proton Transfer Compound Obtained from 2, 6‐Pyridinedicarboxylic Acid and 1, 10‐Phenanthroline: Observation of Strong Intermolecular Hydrogen Bonds

The proton transfer compound LH₂ , (phenH⁺)₂(pydc^2—), has been prepared from 1, 10‐phenanthroline, phen, and 2, 6‐pyridinedicarboxylic acid, (dipicolinic acid), pydcH₂. Characterization was performed using solution and solid phase CP/MAS ¹³C NMR and IR spectroscopy. The reactions of this adduct with ZnSO₄·7H₂O and Zn(NO₃)₂·4H₂O give the complexes, [Zn(pydc)₂][Zn(phen)₂(H₂O)₂]·7H₂O (1) and [Zn(phen)₃]₄(H(Hpydc)₂)(NO₃)₇·26H₂O (2) , respectively. These complexes were characterized by ¹H and ¹³C NMR spectroscopy and single crystal X‐ray analysis. The complexes crystallize in the triclinic space group P1 with Z = 2. The unit cell dimensions for complex 1 and 2 are: a = 9.9838(9) Å, b = 14.7483(13) Å, c = 14.8365(13) Å and a = 12.640(4) Å, b = 15.855(5) Å, c = 21.830(7) Å, respectively. In complex 1 (pydc^2—) and phen, are tri‐ and bidentate ligands, respectively, and an anionic [Zn(pydc)₂]^2— and cationic [Zn(phen)₂(H₂O)₂]²⁺ complex are formed simultaneously. In complex 2 , three phen participate in complexation leaving hydrogen‐bis(pyridine‐2‐carboxylate), (H(Hpydc)₂)^— as a supramolecular anion. The fragments (H(Hpydc)₂)^—, 7 NO₃^—, and 26 H₂O in complex 2 are joined together by extensive and strong H‐bonding; therefore, the structure is composed of [Zn(phen)₃]₄⁸⁺, and an anionic hydrogen bond supramolecular assembly with the formula, {(H(Hpydc)₂(NO₃)₇)^8— · 26H₂O}_n. The anionic species (H(Hpydc)₂)^— has a special position at the inversion center, as well as one of the NO₃^— anions, which is disordered over the inversion center. Most of the hydrogen bonds in complex 2 represent strong H‐bonding. The protonation constants of the building blocks of the pydc‐phen adduct, the equilibrium constants for the reaction of (pydc^2—) with phenanthroline and the stoichiometry and stability of the Zn^II complex with LH₂ on aqueous solution were determined by potentiometric pH titration. The solution study results support self‐association between (pydc^2—) and (phenH⁺) with a stoichiometry for the Zn(II) complex similar to that observed for the isolated crystalline complex.     

Supramolecular Assemblies of Mononuclear and Polymeric Nickel(II) Glutarato Complexes via π‐π Stacking Interactions and Hydrogen Bonds: [Ni(H2O)3(phen)(C5H6O4)] · H2O and [Ni(H2O)2(phen)(C5H6O4)]

Syntheses of the sky blue complex compounds [Ni(H₂O)₃(phen)(C₅H₆O₄)] · H₂O ( 1 ) and [Ni(H₂O)₂(phen)(C₅H₆O₄)] ( 2 ) were carried out by the reactions of 1,10‐phenanthroline monohydrate, glutaric acid, NiSO₄ · 6 H₂O and Na₂CO₃ in CH₃OH/H₂O at pH = 6.9 and 7.5, respectively. The crystal structure of 1 (P 1 (no. 2), a = 14.289 Å, b = 15.182 Å, c = 15.913 Å, α = 67.108°, β = 87.27°, γ = 68.216°, V = 2934.2 ų, Z = 2) consists of hydrogen bonded [Ni(H₂O)₃‐ (phen)(C₅H₆O₄)]₂ dimers and H₂O molecules. The Ni atoms are octahedrally coordinated by two N atoms of one phen ligand, three water O atoms and one carboxyl O atom from one monodentate glutarato ligand (d(Ni–N) = 2.086, 2.090 Å; d(Ni–O) = 2.064–2.079 Å). Through the π‐π stacking interactions and intermolecular hydrogen bonds, the dimers are assembled to form 2 D layers parallel to (0 1 1). The crystal structure of 2 (P2₁/n (no. 14), a = 7.574 Å, b = 11.938 Å, c = 18.817 Å, β = 98.48°, V = 1682.8 ų, Z = 4) contains [Ni(H₂O)₂(phen)(C₅H₆O₄)_2/2] supramolecular chains extending along [010]. The Ni atoms are octahedrally coordinated by two N atoms of one phen ligand, two water O atoms and two carboxyl O atoms from different bis‐monodentate glutarato ligands with d(Ni–N) = 2.082, 2.105 Å and d(Ni–O) = 2.059–2.087 Å. The supramolecular chains are assembled into a 3 D network by π‐π stacking interactions and interchain hydrogen bonds. A TG/DTA of 2 shows two endothermic effects at 132 °C and 390 °C corresponding to the complete dehydration and the lost of phen.     

An Azelaato‐bridged Dinuclear Copper(II) Complex, [Cu2(phen)2(C9H14O4)2] · 6 H2O (phen = 1,10‐phenanthroline)

The title compound [Cu₂(phen)₂(C₉H₁₄O₄)₂] · 6 H₂O was prepared by the reaction of CuCl₂ · 2 H₂O, 1,10‐phenanthroline (phen), azelaic acid and Na₂CO₃ in a CH₃OH/H₂O solution. The crystal structure (monoclinic, C2/c (no. 15), a = 22.346(3), b = 11.862(1), c = 17.989(3) Å, β = 91.71(1)°, Z = 4, R = 0.0473, wR² = 0.1344 for 4279 observed reflections) consists of centrosymmetric dinuclear [Cu₂(phen)₂(C₉H₁₄O₄)₂] complexes and hydrogen bonded H₂O molecules. The Cu atom is square‐planar coordinated by the two N atoms of the chelating phen ligand and two O atoms of different bidentate bridging azelaate groups with d(Cu–N) = 2.053, 2.122(2) Å and d(Cu–O) = 1.948(2), 2.031(2) Å. Two azelaate anions bridge two common Cu atoms via the terminal O atoms (d(C–O) = 1.29(2) Å; d(C–C) = 1.550(4)–1.583(4) Å). Phen ligands of adjacent complexes cover each other at distances of about 3.62 Å, indicating π‐π stacking interaction, by which the complexes are linked to 1 D bands.     

Molecular and Low‐dimensional Coordination Compounds of Copper(II) and 3, 5‐Dimethylpyrazole — Synthesis,Crystal Structure,and Properties

Three 3, 5‐dimethylpyrazole (pz*) copper(II) complexes, [Cu(pz*)₄(H₂O)](ClO₄)₂ ( 1 ), [Cu(pz*)₂(NCS)₂]·H₂O ( 2 ), and [Cu(pz*)₂(OOCCH=CHCOO)(H₂O)]·1.5H₂O ( 3 ), have been synthesized and characterized with single crystal X‐ray structure analysis. 1 crystallizes in the tetragonal space group, 14/m, with a = 14.027 (3) Å, c = 16.301 (5) Å, and Z = 4. 2 crystallizes in the monoclinic space group, P2₁/c, with a = 8.008 (3) Å, b = 27.139 (9) Å, c = 8.934 (3) Å, β = 106.345 (6)°, and Z = 4. 3 crystallizes in the triclinic space group, P1¯, with a = 7.291 (9) Å, b = 10.891 (13) Å, c = 11.822 (14) Å, α = 80.90 (2)°, β = 79.73(2)°, γ = 70.60(2)°, and Z = 2. In 1 , one water molecule and four pz* ligands are coordinated to Cu^II. Two [Cu(pz*)₄(H₂O)]²⁺ units are connected to ClO₄^— via hydrogen bonds. One lattice water molecule is found in the unit cell of 2 , which forms an one‐dimensional chain via intermolecular hydrogen bonds with the N‐H atom of pz*. In 3 , the oxygen atom of the coordinated water molecule is connected with two C=O groups of two neighbouring maleic acid molecules to form a linear parallelogram structure. Another C=O group of maleic acid forms a hydrogen bond with the N‐H atom of pz* to create a two‐dimensional structure. The spectroscopic and bond properties are also discussed.     

Synthesis and Crystal Structure of CeIII and BiIII Complexes and Solution Studies of ZnII,CdII, PbII,CeIII, and BiIII Complexes Obtained from Proton Transfer Compounds Containing 2,6‐Pyridinedicarboxylate Ion

The two complexes (pydaH)₂[Ce(pydc)₂(H₂O)₂]₂ · 2H₂O (1) and (phenH)₂[Bi(pydc)₂(H₂O)]₂ · 5H₂O (2) were prepared from the proton transfer compounds containing the 2,6‐pyridinedicarboxylate ion. 1 was synthesized from the reaction of Ce(NO)₃ · 6H₂O with the proton transfer compound, (pydaH₂)(pydc), (pyda=2,6‐diaminopyridine, pydcH₂=2,6‐pyridinedicarboxylic acid). 2 was synthesized from the reaction of proton transfer compound, (phenH)₂(pydc), (phen=1,10‐phenanthroline), with Bi(NO₃)₃ · 5H₂O. The characterization was carried out using IR, ¹H and ¹³C NMR spectroscopy, elemental analysis and single crystal X‐ray diffraction. The complex 1 crystallizes in the space group of the triclinic system, and contains two molecules per unit cell. The structure has been refined to a final value for the crystallographic R factor of 0.0342 based on 8851 reflections. The unit cell parameters are: a = 9.753(2) Å, b = 10.503(2) Å, c = 10.774(2) Å, α = 83.905(4)°, β = 88.089(4)°, and γ = 82.636(3)°. The crystal structure illustrates that cerium atoms are connected together through the four‐membered ring Ce₂O₂. 2,6‐Pyridinedicarboxylate fragment acts as a tridentate ligand. The molecular structure contains four (pydc)^2? ligands, two of which are bridge ligands linking the two central atoms. The complex 2 crystallizes in the space group of the triclinic system and contains two molecules per unit cell. The unit cell dimensions are: a = 8.8860(4) Å, b = 12.0132(6) Å, c = 13.0766(6) Å, α = 100.967(1)°, β = 96.681(1)° and γ = 94.191(1)°. The structure has been refined to a final value for the crystallographic R factor of 0.0471 based on 9576 reflections. In this complex, 2,6‐pyridinedicarboxylate moiety has acted as a tridentate ligand and the lattice is composed of binuclear unit, [Bi(pydc)₂(H₂O)]₂^2?, (phenH)⁺ counter ions and five lattice waters. In both complexes hydrogen bonds, π‐π stacking and ion‐pairing play important roles in stabilizing the corresponding lattice. The stoichiometry and stability of the Zn^II, Cd^II, Pb^II, and Ce^III complexes with (pydaH₂)(pydc) in aqueous solution were investigated by potentiometric pH titration. The solution studies revealed that the stoichiometry of the crystalline complexes of the proton transfer system (pydaH₂)(pydc) with Ce^III, obtained in this study, and those with Zn^II, Cd^II and Pb^II, reported in our previous studies, are in close agreements. The complexation reactions of phen, pydc, and 2phen+pydc with Bi^III in aqueous solution were investigated by potentiometric pH titrations, and the equilibrium constants for all major complexes formed are described.     

A Sterically Hindered Phosphonic Acid with a Hydrogen‐Bonded Cage Structure: [4‐tert‐Bu‐2,6‐Mes2‐C6H2P(O)(OH)2·H2O]4

The synthesis and molecular structure of the novel phosphonic acid 4‐tert‐Bu‐2,6‐Mes₂‐C₆H₂P(O)(OH)₂ ( 1 ) is reported. Compound 1 crystallizes in form of its monohydrate as a hydrogen‐bonded cluster ( 1·H₂O )₄ comprizing four phosphonic acid molecules (O···O 2.383(3)‐3.006(4) Å). Additionally, sterically hindered terphenyl‐substituted phosphorus compounds of the type 4‐tert‐Bu‐2,6‐Mes₂‐C₆H₂PR(O)(OH) ( 5 , R = H; 7 , R = O₂CC₆H₄‐3‐Cl; 9 , R = OEt) were prepared, which all show dimeric hydrogen‐bonded structures with O···O distances in the range 2.489(2)–2.519(3) Å. Attempts at oxidizing 5 using H₂O₂, KMnO₄, O₃, or Me₃NO in order to give 1 failed. Crystallization of 5 in the presence of Me₃NO gave the novel hydrogen bonded aggregate 4‐tert‐Bu‐2,6‐Mes₂‐C₆H₂PH(O)(OH)·ONMe₃ ( 6 ) showing an O–H···O distance of 2.560(4) Å.     

Syntheses and Crystal Structures of Cadmium Complexes with Thiophenedicarboxylate and Bipyridine‐like Ligands

Two new coordination polymers [Cd(tdc)(bpy)(H₂O)]_n ( 1 ) and [Cd(tdc)(phen)]_n ( 2 ) (H₂tdc = thiophene‐2,5‐dicarboxylic acid, bpy = 2,2′‐bipyridine and phen = 1,10‐phenanthroline) have been synthesized under hydrothermal condition. Their crystal structures have been established by X‐ray single‐crystal diffraction. Complex 1 crystallizes in the orthorhombic space group Fdd2 with a = 14.757(7), b = 45.38(2), c = 10.518(5) Å, V = 7044(6) ų, Z = 16; 2 in the monoclinic space group P2₁/c with a = 7.262(1), b = 21.970(2), c = 10.051(1) Å, β = 105.01(1)°, V = 1548.8(2) ų, Z = 4. Both of them are double‐stranded chains and further assembled into three‐dimensional networks by π‐π stacking interactions. 1 and 2 are stable in air, and show blue photoluminescence at 415 nm and 410 nm, respectively.     

Synthesis and single crystal X‐ray determination of the Schiff base 1‐[(2‐isopropyl‐5‐methylphenoxy)hydrazono] ethyl ferrocene

The reaction of acetylferrocene [Fe(η‐C₅H₅)(η‐C₅H₄COCH₃)] (1) with (2‐isopropyl‐5‐methylphenoxy) acetic acid hydrazide [CH₃C₆H₃CH(CH₃)₂OCH₂CONHNH₂] (2) in refluxing ethanol gives the stable light‐orange–brown Schiff base 1‐[(2‐isopropyl‐5‐methylphenoxy)hydrazono] ethyl ferrocene, [CH₃C₆H₃CH(CH₃)₂OCH₂CONHN?C(CH₃)Fe(η‐C₅H₅)(η‐C₅H₄)] (3). Complex 3 has been characterized by elemental analysis, IR, ¹H NMR and single crystal X‐ray diffraction study. It crystallizes in the monoclinic space group P2₁/n, with a = 9.6965(15), b = 7.4991(12), c = 29.698(7) Å, β = 99.010(13) °, V = 2132.8(7) ų, D_calc = 1.346 Mg m^?3; absorption coefficient, 0.729 mm^?1. The crystal structure clearly shows the characteristic [N? H···O] hydrogen bonding between the two adjacent molecules of 3. This acts as a bidentale ligand, which, on treatment with [Ru(CO)₂Cl₂] _n, gives a stable bimetallic yellow–orange complex (4). Copyright © 2002 John Wiley & Sons, Ltd.     

An Aqua‐Bridged Helical‐Chain Copper(II)‐Saccharinato Polymer Linked into a Two‐Dimensional Supramolecular Framework

A new assembly [Cu₂(sac)₂(μ‐dmea)₂(μ‐H₂O)]_n (sac = saccharinate and Hdmea = 2‐dimethylaminoethanol) has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X‐ray diffraction. The complex crystallizes in the monoclinic space group C2/c and consists of dinuclear modules of [Cu₂(sac)₂(dmea)₂]. The sac ligand is N‐coordinated, while the dmea ligand is in the deprotanated form by losing the ethanol hydrogen atom and acts as a bidentate donor through the alkoxo group and N atom. The alkoxo group also serves as a bridge between two copper(II) ions, leading to an intra‐dimer Cu···Cu separation of 3.0229(7) Å. The dimeric units are bridged by aqua ligands to generate a one‐dimensional water‐bridged helical chain, in which the copper(II) ions exhibit a distorted square‐pyramidal CuN₂O₃ coordination. The Cu–Cu distance in the chain separated by the bridging aqua ligands is 5.297Å. The polymeric chains are further linked by π(sac)···π(sac) and C–H···π(sac) interactions into a two‐dimensional supramolecular network.     

Copper(I) π‐Complexes with 2‐Butyne‐1,4‐diol. Synthesis and Crystal Structure of Na[CuCl2(HOCH2C≡CCH2OH)]·2H2O

Crystals of anionic Na[CuCl₂(HOCH₂C≡CCH₂OH)]·2H₂O π‐complex have been synthesized by interaction of 2‐butyne‐1,4‐diol with CuCl in a concentrated aqueous NaCl solution and characterized by X‐ray diffraction at 100 K. The crystals are triclinic: space group , a = 7.142(3), b = 7.703(3), c = 10.425(4) Å, α = 105.60(3), β = 99.49(3), γ = 110.43(3)°, V = 495.9(4) ų, Z = 2, R = 0.0203 for 3496 reflections. The structure is built of discrete [CuCl₂(HOCH₂C≡CCH₂OH)]^? anionic stacks and polymeric cations among the stacks. The Cu^I atom adopts trigonal planar coordination of two Cl^? anions and the C≡C bond of 2‐butyne‐1,4‐diol, Cu–(C≡C) distance is equal to 1.903(3) Å. Na⁺ cations environment is octahedral and consists of O and Cl atoms. The crystal packing is governed by strong hydrogen bonds of O–H···Cl and O–H···O types.