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We design a series of expanded porphyrins which are incorporated of dithienothiophene (DTT), 2,2′-bithiophene, inverted thiophene ring or selenophene ring and substituted of the pyrrole NH groups by S and Se heteroatoms. The molecule with 2,2′-bithiophene is more stable than the molecule with DTT. The expanded porphyrins with a thiophene or selenophene ring are more stable than the expanded porphyrins with an inverted thiophene or inverted selenophene ring. 6 shows special features due to its increased HOMO-LUMO gap, planar geometry, and strengthened aromaticity. We expect that this work can provide help to design and synthesize stable molecular materials.

On the basis of hard soft acid base theory, two neutral heterometallic M2Pd3 supramolecular cages, [Al2Pd3(L)6Cl6] (1) and [Fe2Pd3(L)6Cl6] (2) (where HL is 1-(4-(1H-imidazol-1-yl)phenyl)butane-1,3-dione), have been constructed by using the tripodal M(L)3 as metalloligands in combination with PdCl2 or Pd(MeCN)2Cl2. The supramolecular cage can be described as a trigonal bipyramid with two M3+ ions occupying at the two axial sites in ΔΔ or ΛΛ configurations and three Pd2+ ions sitting in the three equatorial positions with square planar geometry in trans configuration. The supramolecular cages exhibit high catalytic activity for the Suzuki–Miyaura coupling with arylbromide or arylchrolide and phenylboronic acid in biorenewable solvent glycerol under mild conditions. Moreover, the catalyst can be readily recycled and reused at least five times without loss of catalytic activity. The high catalytic performance may be attributed to the distinct properties of the cage structure with uniformly distributive and well-defined Pd active centres on the cage surfaces. The high stability in the cage structure also prevents Pd leaching out and agglomeration.

Diastereoselective synthesis of bis-cyclometalated Ir(III) stereoisomers Δ/Λ-[Ir(C∧N)2(d-pro)] and Δ/Λ-[Ir(C∧N)2(l-pro)] (where C∧N is 2-phenylpyridine (Hppy), (4,6-difluorophenyl)pyridine (Hdfppy), and 2-phenylquinoline (Hpq) and pro is proline) with dual stereogenic centers at the metal and auxiliary ligand has been developed. The diastereomers Λ-l and Λ-d, and Δ-l and Δ-d exhibit distinguishable photophysical properties in both solution and the solid state. The thermodynamically stable diastereomers Λ-[Ir(ppy)2(l-pro)], Λ-[Ir(dfppy)2(l-pro)], and Λ-[Ir(pq)2(l-pro)] emit a green emission at 524 nm (Φ = 3.5% and τ = 35 ns), a blue-green emission at 480 nm (Φ = 4.5% and τ = 59 ns), and a red emission at 588 nm (Φ = 6.5% and τ = 200 ns) in DCM solution, respectively, which are blue-shifted accompanied by a large quantum yield and long lifetime relative to the corresponding unstable diastereomers Δ-[Ir(ppy)2(l-pro)] at 537 nm (Φ = 2.3% and τ = 29 ns), Δ-[Ir(dfppy)2(l-pro)] at 489 nm (Φ = 2.8% and τ = 43 ns)...

With the idea of supramolecular hosts encircling monoanions, a series of urea-containing trinuclear cationic copper complexes were designed, prepared and structurally analyzed. Copper(I) acetylides [Cu3(μ-dppm)3(μ3-η1-CCC6H4-4-NHC(O)NHC6H4-4-R)2]+ (dppm = bis(diphenylphosphino)methane; R = NO2 (1), CF3 (2), Cl (3), H (4), tBu (5), and OCH3 (6)) were prepared with F−, BF4−, or NO3− present as the anion. Eight 1-D anion coordination polymers (ACPs), 1·F, 2·F, 3·BF4, 4·F, 5·F, 5·BF4, 5·NO3 and 6·0.5F·0.5BF4, were clearly determined by X-ray diffraction. Diversity in the polymeric architecture is generated by both the choice of R-group used and anion present. 2·F, 3·BF4, 4·F, and 5·F show linear 1-D structures; 5·BF4 and 5·NO3 feature single-stranded helical structures; 1·F and 6·0.5F·0.5BF4 exhibit meso-helical structures. Solid state UV-vis absorption and luminescence properties are also discussed.

Chiral precursors Λ-[Ir(ppy)2(l-pro)] (Λ-L, where ppy is 2-phenylpyridine; pro is proline), Λ-[Ir(ppy)2(MeCN)2](PF6) (Λ-1), Δ-[Ir(ppy)2(d-pro)] (Δ-D), and Δ-[Ir(ppy)2(MeCN)2](PF6) (Δ-1) were synthesized from rac-[(Ir(ppy)2)2Cl2] and l-pro or d-pro by means of the auxiliary ligand strategy with 99% de values. The enantiopure mono complexes Λ/Δ-[Ir(ppy)2(L)](PF6) (L is 2,2'-bipyridine, Λ/Δ-2; L is 2,2'-dipyrimidine (dpm), Λ/Δ-3; L is 2,2'-bibenzimidazole (H2bbim), Λ/Δ-4) with 99% ee values and binuclear complexes ΛΛ/ΔΔ-[(Ir(ppy)2)2(dpm)](PF6)2 (ΛΛ-5 and ΔΔ-5) and ΛΛ/ΔΔ-[(Ir(ppy)2)2(bbim)] (ΛΛ-6 and ΔΔ-6) with 99% de values were synthesized in one step using the corresponding chiral precursors. The absolute configurations at Ir(III) centers of precursor Δ-1, mononuclear Λ-3, and binuclear ΔΔ-6 were confirmed by single-crystal structural analysis and characterized by circular dichroism (CD) spectroscopy. The correlation between the absolute configuration at Ir(III) center and CD spectra was established. The configurations at Ir(III) centers are stable during the reactions, and the chiral precursors can be used for the asymmetric synthesis of enantiomerically pure mono- and polynuclear Ir(III) complexes. Moreover, meso ΛΔ-[(Ir(ppy)2)2(dpm)](PF6)2 (meso-5) and ΛΔ-[(Ir(ppy)2)2(bbim)] (meso-6) were also synthesized using these precursors.

The structures and properties of asymmetric heterocycles (HBrBN3) n (n = 1-4) are systematically studied at the B3LYP/6-31G* level. The molecules (HBrBN3) n (n = 2-4) have the core structures of a 2n-membered ring with alternating boron and α-nitrogen atoms. The relationships between geometrical parameters and oligomerization degree n are discussed. The calculated IR spectra have four main characteristic regions. Trends in thermodynamic properties with temperature and oligomerization degree n are discussed. Thermodynamic analysis of the gas-phase oligomerizations shows that formation of the most stable heterocycles (HBrBN3) n (n = 2-4) is enthalpy driven in the range of 200-800 K.

In an attempt to find single-source precursors, a series of small clusters of inorganic azides of indium (Br2InN3) n (n = 1–6) were studied using the dispersion correction density functional theory (wB97XD). The obtained (Br2InN3) n (n = 2–6) clusters have the core structures of 2n-membered ring with alternating indium and α-nitrogen atoms. The influences of cluster size (oligomerization degree n) on the structures, energies, IR spectra, and thermodynamic properties of clusters were discussed. The computed binding energies indicate the stability: 3A > 3B, 4B > 4C > 4A > 4D, 5E > 5D > 5B = 5C > 5A and 6I > 6C > 6D > 6G ≥ 6H > 6F > 6E > 6B > 6A. It is also found that (Br2InN3)2 and (Br2InN3)4 clusters possess higher stability than their neighbor sizes judged by the calculated second-order difference of energies (Δ2 E). Meanwhile, thermodynamic properties for (Br2InN3) n (n = 1–6) clusters increase with the increasing temperature and oligomerization degree n, and the oligomerizations are thermodynamically favorable at temperatures up to 800 K.

Magnetic coordination polymers have attracted considerable interest due to their novel structures and potential applications. In this paper, one new 2D magnetic manganese coordination polymer {[Mn(bimb)(OBA)]}n (1) was synthesized under solvothermal conditions based on 4,4′-bis(1H-imidazol-1-yl-methyl)biphenyl (bimb) and 4,4′-oxybis(benzoate) (H2OBA). Complex 1 contains [Mn(CO2)]n 1D chains and magnetic susceptibility measurements indicate that compound 1 exhibits an antiferromagnetic coupling interaction. In addition, complex 1 exhibits solid-state photoluminescence and high thermal stability.

The DFT-B3LYP/6-311++G(3df,2p) and MP2(full)/6-311++G(3df,2p) calculations were carried out on the binary complex formed by HM (M = Li, Na, K) and XH (X = F, Cl, Br) or C6H6, as well as the ternary system XH⋯HM⋯C6H6. The cooperativity effect between the dihydrogen-bonding and H M⋯π interactions was investigated. The result shows that the H⋯H and H M⋯π interactions are strengthened in the ternary complex in comparison with those in the corresponding binary system. The cooperativity effect of the dihydrogen bond on the H M⋯π interaction is more pronounced than that of the H M⋯π interaction on the H⋯H interaction for the ternary system with HNa or HK, while it is contrary in the ternary complex with HLi. Furthermore, the moderate cooperativity effects between the H⋯H and H M⋯π interactions exist in the ternary complexes with FH, while the remarkable cooperativity effects are present in those with the partially covalent ClH⋯HM or BrH⋯HM dihydrogen-bonding interaction. Cooperativity effects follow the order of XH⋯HNa⋯C6H6 > XH⋯HLi⋯C6H6 > XH⋯HK⋯C6H6 and ClH⋯HM⋯C6H6 > BrH⋯HM⋯C6H6 > FH⋯HM⋯C6H6. Cooperativity effect was analyzed using the surface electrostatic potentials, electron density shifts and AIM (Atoms in Molecules) methods as well as charges of the hydrogen atoms in H⋯H moiety. Although the same optimized geometry is obtained, the cooperativity energy obtained considering that it comes either from “X−⋯H2⋯M+⋯C6H6” or “XH⋯HM⋯C6H6” is different.

Three novel coordination polymers have been synthesized via hydrothermal reactions at different temperatures, namely [Cu2(H2tcbi)(H2O)4] (1), [Cd3(H3tcbi)2(H2O)6]·2H2O (2) and [Ca(H4tcbi)(H2O)2] (3) (H6tcbi = 4,4′,5,5′-tetracarboxyl-2,2′-biimidazole). This is the first report on complexes of the Hntcbi ligand. Single crystal X-ray analyses reveal that they have rich structural chemistry, ranging from one-dimensional (1), to two-dimensional (2 and 3). Three different coordination modes of the H6tcbi ligand, μ2, μ3 and μ4, have been observed. The coordination geometries of the metal sites vary from five-coordinate square pyramidal, six-coordinate octahedral to seven-coordinate pentagonal bipyramidal. The H6tcbi ligand in complexes 1, 2 and 3 is tetra-deprotonated to H2tcbi4−, tri-deprotonated to H3tcbi3− and bi-deprotonated to H4tcbi2−, and coordinates to the metal ions as a tetradentate, pentadentate and pentadentate ligand respectively, resulting in the formation of 1D, 2D and 2D coordination polymers. Photoluminscent investigation of complexes 2 and 3 shows intense blue and green fluorescent emissions respectively.

Two isostructural 1D coordination polymers {[Ln(OAc)2(H2O)(OBPT)]·3H2O}n (HOBPT = 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol, Ln = Eu(3+), 1; Tb(3+), 3) and two discrete complexes [Ln(OAc)2(DMF)2(OBPT)] (Ln = Eu(3+), 2; Tb(3+), 4) have been synthesized in H2O-MeOH or DMF solvents, respectively. Their structures were identified by powder X-ray diffraction. Single-crystal X-ray studies for complexes 1 and 2 revealed that the coordination geometries of the Eu(3+) ions are similar and can be described as a distorted tricapped trigonal prism with six oxygen atoms and three nitrogen atoms. The difference between them is that one aqua ligand and one oxygen atom from the OBPT ligand complete the coordination sphere in complex 1, whereas two DMF molecules complete the coordination sphere in complex 2. Interestingly, the solvent-mediated, reversible crystal-to-crystal transformation between them was achieved by immersing the crystalline samples in the corresponding solvent (H2O or DMF) or by exposing them to solvent vapor. Complex 1 shows a highly selective luminescence enhancement in response to DMF in comparison to that observed in response to other examined solvents such as acetone, ethyl acetate, ethanol, acetonitrile, methanol, and THF.

The novel three-dimensional chiral framework of the four-coordinate zinc complexes, [Zn 4 (biim) 3 (ina) 2 ] ( 1a and 1b ) (H 2 biim = 2,2′-biimidazole, ina = isoniconate), has been prepared via hydrothermal reaction. X-ray single crystal diffraction analysis shows the biim 2− in title complexes acts as a tetradentate ligand and links four different Zn 2+ ions. Spontaneous chiral resolution occurs in solvo-thermal reaction, which was confirmed by solid-state circular dichroism spectra. Photoluminescent spectra of compound 1 exhibit an intense blue emission at 440 nm.

Polyrotaxane metal-organic frameworks (PMOFs) have attracted considerable attention due to their aesthetic topologies and potential biological applications. In this paper, we synthesized two kinds of hcb networks with nanoscale macrocycles. The hcb networks interlocked with each other in inclined and parallel interlocking modes respectively, giving rise to two new PMOFs, {[Ni(DPDBT)(bdc)]·(H2O)2}n (1) and {[Zn(DPDBT)(fuma)]}n (2). DFT calculations are used to elucidate why the inclined interlocking mode is preferential for 1 while the parallel interlocking mode is preferential for 2. The networks of 1 with a parallel interlocking mode, as well as 2 with an inclined interlocking mode, were simulated. The total energies of the parallel and inclined structures proved that the as-synthesized interlocking modes of 1and 2 are more stable. Moreover, photophysical properties and thermal analyses of related ligands and complexes are investigated and discussed in detail.

College of Chemistry, Jilin University, Changchun 130023, P.R. ChinaReceived December 23, 2011, Accepted June 8, 2012We have theoretically investigated the magnetic properties of N-confused porphyrin (NCP), tetraphenyl-N-confused porphyrin (TPNCP) and their substituted derivatives with O, S and Se heteroatoms (2ONCP,2STPNCP, 2SeNCP, 2OTPNCP, etc.) by using DFT method. In the minimum energy structures of the2OTPNCP, the two couples opposite phenyl substitutes are staggered. In the case of TPNCP, 2STPNCP and2SeTPNCP, two phenyls being respectively close to or opposite to N-confused pyrrole are found to be pointedthe same direction, whilst others are in the opposite direction. Based on the equilibrium structures, the

Six new complexes [Zn2(L1)4]·2H2O·DMF (1), [Zn2(L2)4]3·13H2O (2), [Zn1.5(L3)3]2 (3), Zn(L4)2·2H2O (4), Zn(L5)2·2CHCl3 (5), and [Zn(L6)2]2 (6) (where HL1 = 1-(4-(1H-imidazol-1-yl)phenyl)butane-1,3-dione, HL2 = 1-(4-(1H-benzimidazol-1-yl)phenyl)butane-1,3-dione, HL3 = 1-(4-(1H-pyrazol-1-yl)phenyl)butane-1,3-dione, HL4 = 1-(3-(1H-imidazol-1-yl)phenyl)butane-1,3-dione, HL5 = 1-(3-(1H-benzimidazol-1-yl)phenyl)butane-1,3-dione and HL6 = 1-(3-(1H-pyrazol-1-yl)phenyl)butane-1,3-dione) have been synthesized by the reaction of the bifunctional ligands and Zn(II) salts under similar experimental conditions. Structural analyses show that the ligands act as a tridentate and bind to two Zn(II) ions as a two-connected linker, generating a variety of geometries from discrete binuclear [2 + 2] metallomacrocycles (3 and 6) to a one-dimensional looped-chain coordination polymer (4) and two-dimensional (4,4) network (5) as well as three-dimensional frameworks with lvt (1) and NbO (2) topologies. The results demonstrate that ...

The geometry, electronic structure, and spectroscopic properties together with the fluoride binding nature of the luminescent rhenium(I) tricarbonyl diimine complex with a triarylboron moiety, [(arB)Re(CO)3(phen)] were investigated by density functional theory (DFT) approach, where, arB = (2,3,5,6-tetramethyl-4-ethynyl-benzene) 3 B, phen = 1,10-phenanthroline), The simulated UV–vis absorptions by M06 functional are in excellent agreement with the experimental results. All absorptions are attributed to intra-ligand charge-transfer (ILCT) within the triarylboron ligand but being disturbed by some contribution of metal-to-arylboron ligand charge-transfer (MLCT) characters. Moreover, the 676 nm phosphorescence computed by TPSSh functional originates from the 3 LLCT/ 3 LMCT transition. Binding the F − results in the re-configuration of the molecular geometry and the variation of the optical properties. The highest energy absorption band is intensified while the lower energy absorption bands are weakened and blue-shifted slightly. The emission maximum is red-shifted to 875 nm after binding the F − .

A monomeric complex [Co(Im)2(O2CMe)2] (1) and a novel aquabridged dimeric complex [Co2(μ-H2O)(μ-CMe)2(Im)4-(O2CMe)2] (2) (Im = imidazole) have been synthesized and characterized. Complexes 1 and 2 coexisted in solution. Pure forms of either complex can be obtained from the same solution by controlling the crystallization conditions. All two complexes possess a carboxylate-Im-cobalt(II) triad system analogous to the carboxylate-histidine-metal triad systems that have been found in many zinc enzymes and cobalt(II)-substituted enzymes. In 2, two Co2+ ions are connected by a water molecule in a bridging fashion with Co°Co [0.3687(1) nm], Co—OH2 [0.2159(3) nm], and Co-OH2-Co [117.2(3)°], in which the water molecule is further stabilized by two intramolecular hydrogen bonds with the oxygens of the terminal monodentate acetate groups with the distance of O…0 [0.2609(7) nm]. The terminal monodentate acetate groups display quite abnormal geometry due to the strong “pulling effect” on the carboxylates by intermolecular and intramolecular hydrogen bonds. Complex 2 showed weak antiferromagnetic coupling at low temperature with g = 2.22 and J = −1.60 cm−1.

The red phosphorescent osmium(II) complexes [Os(LR)2(PH3)2] (L = 2-pyridyltriazole (ptz): R = H (1a), CF3 (1b), t-Bu (1c)); L = 2-pyridylpyrazole (ppz): R = H (2a), CF3 (2b), t-Bu (2c)); L = 2-phenylpyridine (ppy): R = H (3a)) were explored using density functional theory (DFT) methods. The ground- and excited-state geometries of the complexes were optimized at the B3LYP/LANL2DZ and UB3LYP/LANL2DZ levels, respectively. The absorption and phosphorescence of the complexes in CH2Cl2 media were calculated based on the optimized ground- and excited-state geometries using time-dependent density functional theory method with the polarized continuum model. The optimized geometry structural parameters of the complexes in the ground state agree well with the corresponding experimental values. The lower-lying unoccupied molecular orbitals of the complexes are dominantly localized on the L ligand, while the higher-lying occupied ones are composed of Os(II) atom and L ligand. The low-lying metal-to-ligand and intraligand charge transfer (MLCT/ILCT) transitions and high-lying ILCT transitions are red-shifted with the increase in the π-donating ability of the L ligand and the π electron-donating ability of R substituent. The calculation revealed that the phosphorescence originated from 3MLCT/3ILCT excited state. However, the complex 3a displayed different types of MLCT/ILCT excited state compared with that of 1a–2c, and the different types of transition were also found in the absorption. In addition, we found that the phosphorescence quantum efficiency of Os(II) complexes is related to the metal composition in the high-energy occupied molecular orbitals, it will be helpful to designing highly efficient phosphorescent materials.

We describe the first observation of the quantitative and rapid synthesis ofa (10,3)-b three-dimensional hydrogen bonded network {[Ru(H 2 biim) 3 ](TMA)}·5H 2 O(1·H 2 O)(H 2 biim = 2,2'-biimidazole; H3TMA = trimesic acid) via a "liquid-assisted" solid-state reaction approach. The reaction occurs within minutes of grinding together [Ru(H 2 biim) 3 ](PF 6 ) 2 and Na 2 HTMA with a few drops of H 2 O 2 as an oxidant and solvent, concomitant with a color change from yellow (Ru(II) ion) to blue-green (Ru(III) ion). The characterization of the solid-state product was achieved by a combination of a single crystal obtained via seeding and powder diffraction experiments. To compare with the solid-state reaction, similar reactions were also carried out in an EtOH solution. Two complexes {[Ru(H 2 biim) 3 ](TMA)}·10H 2 O(2·H 2 O) and [Ru(H 2 biim) 3 ](HTMA) (3) were isolated in the presence of a polypyridine base, such as 2,2-dipyridylamine or 2,2':6',2"-terpyridine or 1,10-phenanthroline. Complex 2 is a (6,3) honeycomb two-dimensional hydrogen-bonded network. Complexes 1 and 2 are topological isomers. The formation of multiple robust hydrogen bonds between [Ru(H 2 biim) 3 ] 3+ and TMA may trigger the proton transfer from H 2 biim to TMA, then electron transfer, resulting in Ru(III) status. This may provide an effective approach for the generation of high status metal complexes via supramolecular interactions. Importantly, our experiments suggest that solution crystallization may at times offer more product diversity than grinding.

Electronic structures and spectroscopic properties of self-assembled [Pt2M4(C≡CH)8] (M=Cu, Ag) clusters have been studied by the TD-DFT (time-dependent density functional theory) calculations with the polarizable continuum model (PCM). The ground- and excited-state structures were optimized by the DFT (density functional theory) methods. The calculated structures and spectroscopic properties are in agreement with the corresponding experimental results. The [Pt2Ag4(C≡CH)8] clusters have two stable ground state geometries (D 4 and D 4h symmetry). The calculated Pt-M distances suggest only very weak interactions. The Cu-Cu distances are larger than the van der Waals radii of two Cu atoms and the Ag-Ag distances are analogous with the sum of van der Waals radii of two Ag atoms. Upon excitation, the interaction of Pt⋯M, Ag⋯Ag is strengthened, while the Cu⋯Cu distances are shortened but they are still larger than the sum of van der Waals radii of two Cu atoms. The lowest-energy absorptions are at 450, 365 and 375 nm and the emissions are at 611, 431 and 435 nm for [Pt2Cu4(C≡CH)8], [Pt2Ag4(C≡CH)8] (A) and (B), respectively. The transitions are all perturbed by the Cu or Ag composition through the UV-Vis spectra region; therefore, there are not pure ILCT or MPtLCT characteristics (ILCT: intraligand charge transfer; MLCT: metal-to-ligand charge transfer) in absorptions of heteropolynuclear [Pt2M4(C≡CH)8] clusters. Since the emissions and the lowest-absorptions have different transition characteristics for each complex, the emissions should not come from the lowest-energy absorptions. Because the M⋯M interactions in the excited state of [Pt2Ag4(C≡CH)8] are augmented, the emissions of [Pt2Ag4(C≡CH)8] clusters bear prominent ILCT character, which is the reason why the emission wavelengths of [Pt2Ag4(C≡CH)8] have a small hypsochromic shift relative to the emission wavelength of homoleptic [Pt(C≡CH)4]2− precursor.

We report a combinational DFT and TD-DFT study of the electronic and optical properties of several tridentate cyclometalated mononuclear [Pt(C^N^N)(C CR)] ( 1 – 3 ), [Pt(C^N^N)(C CRC CH)] ( 4 ), and dinuclear [Pt(C^N^N)(C CRC C)Pt(C^N^N)] ( 5 ( C 2 symmetry) and 5 ′ ( C s symmetry)) platinum(II) complexes with σ-acetylide ligand bearing fluorene substituents, where HC^N^N = 6-aryl-2,2′-bipyridine, R = fluorene-2,7-diyl 1 , 4 , 5 and 5 ′ , R = 9,9-dimethylfluorene-2,7-diyl 2 , R = 9,9-diethylfluorene-2,7-diyl 3 . The structural and electronic properties of the ground- and lowest triplet state and the EA and IP values of the complexes are discussed. It is found that all of the lowest-lying absorptions are categorized as the LLCT combined with the MLCT transitions. The oscillator strengths of the lowest energy absorptions get a remarkable enhancement for the dinuclear complexes 5 and 5 ′compared to 1 – 4 due to the increase of electronic delocalization on the more planar molecular geometry. In general, the phosphorescent emissions of these complexes in CH 2 Cl 2 are the reverse process of their lowest energy absorption transitions, except that of 4 is assigned as 3 [π∗−π]/ 3 MLCT transition because of the strengthened electronic localization effect and the interaction with the solvent in the lowest triplet state. In addition, these complexes hold promise as a new kind of nonlinear optical material owing to their large static first hyperpolarizabilities ( β 0 ). The β 0 value has increased in the dinuclear complexes in contrast to those of the mononuclear ones owing to their larger transition moment and smaller transition energy.

The ground and the lowest-lying triplet excited state geometries, electronic structures, and spectroscopic properties of a novel series of neutral iridium(III) complexes with cyclometalated alkenylquinoline ligands [(C^N) 2 Ir(acac)] (acac = acetoylacetonate; C^N = 2-[( E )-2-phenyl-1-ethenyl]pyridine (pep) 1 ; 2-[( E )-2-phenyl-1-ethenyl]quinoline (peq) 2 ; 1-[( E )-2-phenyl-1-ethenyl]isoquinoline (peiq) 3 ; 2-[( E )-1-propenyl]pyridine (pp) 4 ; 2-[( E )-1-fluoro-1-ethenyl]pyridine (fpp) 5 ) were investigated by DFT and CIS methods. The highest occupied molecular orbital is composed of d (Ir) and π(C^N) orbital, while the lowest unoccupied molecular orbital is dominantly localized on C^N ligand. Under the TD-DFT with PCM model level, the absorption and phosphorescence in CH 2 Cl 2 media were calculated based on the optimized ground and triplet excited state geometries, respectively. The calculated lowest-lying absorptions at 437 nm ( 1 ), 481 nm ( 2 ), 487 nm ( 3 ), 422 nm ( 4 ), and 389 nm ( 5 ) are attributed to a {[ d x 2 - y 2 (Ir) + d xz (Ir) + π(C^N)] → [π∗(C^N)]} transition with metal-to-ligand/intra-ligand charge transfer (MLCT/ILCT) characters, and the calculated phosphorescence at 582 nm ( 1 ), 607 nm ( 2 ), 634 nm ( 3 ), 515 nm ( 4 ), and 491 nm ( 5 ) can be described as originating from the 3 {[ d x 2 - y 2 (Ir) + d xz (Ir) + π (C^N)] [π∗(C^N)]} excited state with the 3 MLCT/ 3 ILCT characters. The calculated results revealed that the phosphorescent color of these new Ir(III) complexes can be tuned by changing the π-conjugation effect strength of the C^N ligand.

A nanocage complex [Co(H2O)6⊂Co8L12](NO3)6·12H2O (1) (HL = 2-amino-4,6-bis(2-pyridyl)-1,3,5-triazin) has been synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction. A [Co(H2O)6]2+ ion as a guest is included in the central cavity of the cubelike nanocage [Co(H2O)6⊂Co8L12]6+ cation, assembled by 8 cobalt ions at the corners and 12 bis-bidentate ligands L at the edges, via the formation of 12-fold strong hydrogen bonds between the six coordinated water molecules and the nitrogen atoms of 12 L ligands. When compound 1 cocrystalizes with KHCO3 and trimesic acid (H3TMA), complexes [Co(H2O)6⊂Co8L12](HCO3)6·24H2O (2) and [Co(H2O)6⊂Co8L12](H2TMA)6·6EtOH·3H2O (3) are obtained, respectively. In 2, a planar [(HCO3)2]2− dimer motif R22(8) synthon plus six lattice water molecules constitute a planar supramolecular synthon R88(20), which acts as a 4-connector, generating a three-dimensional (3D) hydrogen-bonded NbO net with an approximately 20 A diameter cavity. In 3, the R44(24...

A series of ruthenium(II) complexes Ru(fppz)2(CO)L [fppz = 3-trifluoromethyl-5(2-pyridyl)pyrazole; L = pyridine (1), 4-dimethylaminopyridine (2), 4-cyanopyridine (3)] were designed and investigated theoretically to explore their electronic structures, absorption, and emissions as well as the solvatochromism. The singlet ground state and triplet excited state geometries were fully optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ level, respectively. The HOMO of 1–3 is composed of dyz(Ru) atom and π(fppz). The LUMO of 1 and 2 is dominantly contributed by π*(fppz) orbital, but that of 3 is contribute by π*(L). Absorption and phosphorescence in vacuo, C6H12, and CH3CN media were calculated using the TD-DFT level of theory with the PCM model based on the optimized ground and excited state geometries, respectively. The lowest-lying absorption of 1 and 2 at 387 and 391 nm is attributed to {[dyz(Ru) + π(fppz)] → [π*(fppz)]} transition, but that of 3 at 479 nm is assigned to {[dyz(Ru) + π(fppz)] → [π*(L)]} transition. The phosphorescence of 1 and 2 at 436 and 438 nm originates from 3{[dyz(Ru) + π(fppz)] [π*(fppz)]} excited state, while that of 3 at 606 nm is from 3{[dyz(Ru) + π(fppz)] [π*(L)]} excited state. The calculation results showed that the absorption and emission transition character can be changed from MLCT/ILCT to MLCT/LLCT transition by altering the substituent on the L ligand. The phosphorescence of 1 and 2 does not have solvatochromism, but that of 3 at 606 nm (vacuo), 584 nm (C6H12), and 541 nm (CH3CN) is strongly dependent on the solvent polarity, so introducing electron-withdrawing group on ligand L will induce remarkable solvatochromism.

Five different cobalt complexes were synthesized by the combination of the multidentate ligand 2,2′-bibenzimidazole (H2bbim) and the coordination plasticity of cobalt ion in the presence of 4-cyanopyridine under hydrothermal conditions using temperature as the only independent variable. The structural features of theses complexes, which ranged from zero-dimensional (0D) in [Co(Hbbim)3]·3H2O (1) and [Co(ina)2(H2O)4] (5) to two-dimensional (2D) layer in {[Co4(Hbbim)4(bbim)2]·2H2O}n (2) or three-dimensional (3D) networks in [Co2(Hbbim)(bbim)2(H2O)]n (3) and [Co5(Hbbim)(bbim)3(ina)2(μ3-OH)]n (4), were extremely dependent on the reaction temperature. At 130 °C, discrete 1 was the unique product. However, 4 was the main product when the reaction temperatures were set in the range of 160−200 °C. 2 and 3 yielded at 140 °C as main products. In spite of the structural diversity of this system, crystallographic studies reveal that the H2bbim ligand typically displays tridentate (Hbbim−) and/or tetradentate (bbim2−) ...

The ground- and excited-state structures for a series of Os(II) diimine complexes [Os(N ∧ N)(CO) 2 I 2 ] (N ∧ N = 2,2′-bipyridine (bpy) ( 1 ), 4,4′-di- tert -butyl-2,2′-bipyridine (dbubpy) ( 2 ), and 4,4′-dichlorine-2,2′-bipyridine (dclbpy) ( 3 )) were optimized by the MP2 and CIS methods, respectively. The spectroscopic properties in dichloromethane solution were predicted at the time-dependent density functional theory (TD-DFT, B3LYP) level associated with the PCM solvent effect model. It was shown that the lowest-energy absorptions at 488, 469 and 539 nm for 1 – 3 , respectively, were attributed to the admixture of the [d xy (Os) → π ∗ (bpy)] (metal-to-ligand charge transfer, MLCT) and [p(I) → π ∗ (bpy)] (interligand charge transfer, LLCT) transitions; their lowest-energy phosphorescent emissions at 610, 537 and 687 nm also have the 3 MLCT/ 3 LLCT transition characters. These results agree well with the experimental reports. The present investigation revealed that the variation of the substituents from H → t -Bu → Cl on the bipyridine ligand changes the emission energies by altering the energy level of HOMO and LUMO but does not change the transition natures.

Six complexes containing the 2,2′-biimidazole-like ligand and chloride, namely, trans-[Ni(H2biim)2(H2O)2]Cl2 (1), trans-[Co1.5(H2biim)3(H2O)3]Cl3 (2), [Zn(H2biim)2Cl]Cl (3), [Ni2(H2bbim)4(bbim)]Cl2 (4), [Co(H2bbim)3]Cl2·2H2O (5), and [Zn2(Hbbim)2(bbim)0.5Cl] (6) (where H2biim = 2,2′-biimidazole, H2bbim = 2,2′-bibenzimidazole) have been synthesized by the reactions of the H2biim or H2bbim ligand with the metal chloride salts. The structures of the complexes were determined by single-crystal X-ray diffraction analyses, and the results revealed that the distances of N···Cl varied from 3.10 to 3.29 A and the angles of N−H···Cl varied from 148 to 169°, O···Cl varied from 3.09 to 3.16 A, O−H···Cl varied from 151 to 178°, C···Cl varied from 3.49 to 3.69 A, and C−H···Cl varied from 122 to 167°. The chloride may act as a multi hydrogen bonded acceptor varying from 3 to 6, resulting in an important collective contribution to cohesion. The data observed in this study seem to suggest that a variety of X−H···Cl (X = N...

The electronic structures and spectroscopic properties of a series of mixed bis-cyclometalated iridium(III) complexes [Ir(ppy) 2 X 2 ] − (X = CN, 1 ; X = NCS, 2 ; X = NCO, 3 ; ppy = 2-phenylpyridl) were investigated at the B3LYP/LANL2DZ and CIS/LANL2DZ levels. The calculated geometry parameters in the ground state are well consistent with the corresponding experimental values. The HOMO of 1 is dominantly localized on Ir atom and ppy ligand, but the HOMO of 2 and 3 have significant X ligand composition. Under the TD-DFT level with PCM model, the absorption and phosphorescence in CH 2 Cl 2 media were calculated based on the optimized geometries in the ground and excited states, respectively. The lowest-lying absorption of 1 at 403 nm is attributed to { [ d x 2 - y 2 ( Ir ) + d xy ( Ir ) + π ( ppy ) ] → [ π ∗ ( ppy ) ] } transition with metal-to-ligand and intraligand charge transfer (MLCT/ILCT) transition characters, whereas those of 2 (449 nm) and 3 (475 nm) are related to { [ d x 2 - y 2 ( Ir ) + d xy ( Ir ) + π ( ppy ) + π ( NCS / NCO ) ] → [ π ∗ ( ppy ) ] } transition with MLCT/ILCT and ligand-to-ligand charge transfer (LLCT) transition characters. The phosphorescence of 1 at 466 nm can be described as originating from 3 { [ d x 2 - y 2 ( Ir ) + d xy ( Ir ) + π ( ppy ) ] [ π ∗ ( ppy ) ] } excited state, while those of 2 (487 nm) and 3 (516 nm) originate from 3 { [ d x 2 - y 2 ( Ir ) + d xy ( Ir ) + π ( ppy ) + π ( NCS / NCO ) ] [ π ∗ ( ppy ) ] } excited states. The calculated results showed that the transition character of the absorption and emission can be changed by adjusting the π electron-accepting abilities of the X ligands and the phosphorescent color can be tuned by altering the X ligands.

The ground- and excited-state geometries, electronic structures, absorptions, and emissions of two ruthenium(II) complexes Ru(bpy) 2 (N ^ N) [bpy = 2,2'-bipyridine, N ^ N = hydrazone (1) and azine (2)] were investigated theoretically. Their ground and the excited state geometries were fully optimized at the B3LYP/MP2/LANL2DZ and UB3LYP/UMP2/LANL2DZ levels, respectively, and the calculated geometries are consistent with the X-ray results. At the TD-DFT level with the PCM model, the absorptions and phosphorescence properties of 1 and 2 were calculated on the basis of the optimized ground- and excited-state geometries, respectively. The calculated lowest-lying absorptions of 1 (512 nm) and 2 (598 nm) are attributed to a {[d x2-y2 (Ru) + d xy (Ru) + π(N^N)] - [π*(bpy)]} transition with MLCT/LLCT transition characters and a {[d z 2(Ru) + d xy (Ru)] → [π*(N^N)]} transition with dominant MLCT transition character, respectively. The calculated phosphorescence of 1 (638 nm) and 2 (731 nm) can be described as originating from a 3 {[d x 2 -y 2(Ru) + d xy (Ru) + π(N^N)] [π*(bpy)]} excited state with 3 MLCT/ 3 LLCT character and a 3 {[d z 2(Ru) + d x 2 -y 2(Ru)] [π*(N^N)]} excited state with dominantly 3 MLCT character, respectively. The calculated results showed that the modulation of the lowest 3 MLCT excited state of this kind of Ru complexes can be achieved by changing the N^N ligand from hydrazone to azine. Moreover, the fact that 2 displays phosphorescence but 1 does not can be interpreted by the different properties of the 3 MLCT excited state: the 3 MLCT excited state of 2 is more than 60 % occupied, whereas that of 1 is less than 20% (k r1 k nr2 ).

The electronic geometries and spectroscopic properties of trans -dioxo- and monooxo-osmium (VI) complexes have been investigated theoretically. The geometry structures of the complexes were fully optimized using the B3LYP/LANL2DZ method for the ground state and the CIS/LANL2DZ method for the excited state. The calculated geometry parameters agree well with the available experimental data in the ground state. The bond length of Os O bond is lengthened in excited state relative to that of the ground state for trans -dioxo-osmium (VI) complexes, but shorten for monooxo-osmium (VI) complexes. Among the calculated dipole-allowed absorptions at λ > 240 nm, the intense absorptions of the complexes were mainly attributed to p z (O) (L = oxalate or malonate) → π ∗ (Os O) + π ∗ (C O), and the composition of p z (O) participate in the transition for monooxo-osmium (VI) complexes. The lowest energy absorptions of the complexes were mainly attribute to Os(d xy ) + π(L) → π ∗ (Os O). The calculated phosphorescence emissions of the complexes were originated from 3 [(π ∗ (Os O) + π ∗ (L)) 1 ((d xy (Os) + π ∗ (L)) 1 ] excited state. The calculation revealed that the emissions of the monooxo-osmium complexes are blue-shift compared with dioxo-osmium complexes when the ligands are same, and the lowest excited energy is higher when the ring is larger (i.e., the electron-donating groups are added) for these two kinds of the complexes.

We explored the electronic structures and spectroscopic properties of [Pt(Me 4 NCN)]Cl ( 1 ) (NCN − = [2,6-(CH 2 NMe 2 ) 2 -C 6 H 3 ] − ) and its SO 2 adducts, [Pt(Me 4 NCN)(SO 2 )]Cl, which show three penta-coordinated modes ( trans - η 1 -pyramidal ( 2 ), cis - η 1 -pyramidal ( 3 ) and η 1 -coplanar ( 4 )), using the theoretical methods. For 2 , a comparative study of ab initio and density functional theory (DFT) shows that the DFT method cannot describe molecular structures appropriately, especially the Pt–S bonding. Therefore, the structures of 1 – 4 in the ground state were optimized by the ab initio MP2 method and those of the first two complexes in the lowest-lying triplet excited state were studied by the unrestricted MP2 method. The present studies reveal that trans - η 1 -pyramidal SO 2 coordination mode is the most stable in the three conformations of [Pt(Me 4 NCN)(SO 2 )]Cl because of its lower total energy as well as the most overlapping between the HOMO and LUMO of SO 2 and the filled Pt d orbital, and least repulsion between the lone pair orbitals of SO 2 and the Lewis base (PtNCN). The spectroscopic calculations at the TD-DFT associated with the Polarizable Continuum Model (PCM) level indicate that the adsorption of SO 2 changes the nature of low-lying absorptions of 1 , agreeing well with the color change observed in experiments. We predicted the phosphorescent emissions in the CH 2 Cl 2 solution at 778 and 552 nm for 1 and 2 , respectively. The coordination of SO 2 into Pt atom results in a significant blue shift in emission energy.

The reaction of 1,3-bis(4,5-dihydro-1H-imidazol-2-yl)benzene (bib) ligand with silver(I) nitrate in a 1:1 molar ratio generated a [2 + 2] metallocyclic complex [Ag2(bib)2](NO3)2 · 2H2O, in which bib ligand displayed in cis configuration. When the additional competing ligands/counterions, such as oxlate salt, 1,2-diaminoethene (en), 1,3-diaminopropane (pn), NO 2 - and VO 3 - were introduced, respectively, to the above-mentioned reaction solution, ring-open polymerization of sliver(I) complexes {[Ag(bib)]NO3 · H2O}n (1), {[Ag(bib)2]X}n ( X = NO 3 - (2), ClO 4 - (3)), {[Ag2(bib)2(NO2)](NO2) · 19/8H2O}n (4) and {[Ag2(bib)2](V4O12)0.5 · 3H2O · 2MeCN}n (5) were generated. In compounds 1, 4 and 5, bib ligand adopts trans configuration and twists around the Ag–Ag axis, giving rise to single-stranded helical structure with short adjacent Ag⋯Ag distances of 3.56, 3.56, 3.50 and 3.63 A, respectively. Compounds 2 and 3 are 1D coordination polymers fusing the [2 + 2] metallocycle [Ag2(bib)2]2+, in which bib ligand exhibits in cis configuration and the metallocycles have longer Ag⋯Ag distances of 8.52 A in 2 and 8.61 A in 3 along with the strong intracyclicπ–π interactions between phenyl groups. Cis and trans configurations of bib coexist in solution and crystallize in complexes 1 and 2 in the solid state in the presence of en or pn. The solution of 1 and 2 can be converted into 3 via the addition of the bulky ClO 4 - counter anion or into 4 through introduction of the competing ligand/conuterion NO 2 - .

The geometries, electronic structures, and spectroscopic properties of a series of novel cationic iridium(III) complexes [trans-(C/N)(2)Ir(PH(3))(2)]+ (C/N = 2-phenylpyridine, 1; benzoquinoline, 2; 1-phenylpytazolato, 3; 2-(4,6-difluorophenyl)pyridimato, 4) were investigated theoretically. The ground- and excited-state geometries were optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels, respectively. The optimized geometry structural parameters agree well with the corresponding experimental results. The unoccupied molecular orbitals are dominantly localized on the C/N ligand, while the occupied molecular orbitals are composed of Ir atom and C/N ligand. Under the time-dependent density functional theory (TDDFT) level with the polarized continuum model (PCM) model, the absorption and phosphorescence in acetonitrile (MeCN) media were calculated based on the optimized ground- and excited-state geometries, respectively. The calculated results showed that the lowest-lying absorptions at 364 nm (1), 389 nm (2), 317 nm (3), and 344 nm (4) are all attributed to a {[d(yz)(Ir) + pi(C/N)] --> [pi*(C/N)]} transition with metal-to-ligand and intraligand charge transfer (MLCT/ILCT) characters; moreover, the phosphorescence at 460 (1) and 442 nm (4) originates from the 3{[d(yz)(Ir) + pi(C/N)] [pi*(C/N)]} (3)MLCT/(3)ILCT excited state, while that at 505 (2) and 399 nm (3) can be described as originating from different types of (3)MLCT/(3)ILCT excited state (3){[d(xy)(Ir) + pi(C/N)] [pi*(C/N)]}. The calculated results also revealed that the absorption and emission transition character can be altered by adjusting the pi electron-withdrawing groups and, furthermore, suggested that the phosphorescent color can be tuned by changing the pi-conjugation effect of the C/N ligand.

Two manganese(II) coordination polymers, [Mn2(bpt)(pa)2(N3)]n [1; Hpa = picolinic acid, Hbpt = 3,5-bis(2-pyridyl)-4H1,2,4-triazole] and [Mn3(ina)2(pa)2(N3)2]n (2; Hina = isonicotinic acid), have been synthesized by solvothermal treatment, in which the ligands bpt and pa were generated in situ by cyclocondensation and hydrolysis of 2-pyridylamidrazone, respectively. In 1, each binuclear subunit [Mn2(bpt)(N3)] bridged by bpt and N3 – ligands is interlinked to four adjacent subunits via four tridentate pa ligands into a diamondoid 3D network, which shows spin-canting magnetism arising from

Structural, electronic, and optical properties of a series of π-conjugated chain type oligomers composed of the bipyridyl, ethynyl and thiophenyl fragments are studied by advanced quantum chemical methods. The properties of the P-oligomers ( P1 – P4 , with 1–4 repeating units, respectively) and the corresponding DP-oligomers ( DP2 – DP4 , with 2–4 repeating units, respectively, but without the terminal thiophenyl fragments) are compared. The geometry optimization results at B3LYP/6-31G level show that all the fragments involved in both the P-oligomers and DP-oligomers in the ground state exhibit a zigzag chain within the molecular plane. The TD-DFT calculations reveal that the dipole-allowed lowest-lying X 1 A → A 1 B absorption band of each oligomer possesses the π → π ∗ transition characters. The geometry structures of P1 , P2 and DP2 in the excited state have been studied by the CIS method, the fluorescence of them revealed by TD-DFT method is originated from the 1 [ππ ∗ ] excited state. Upon increasing the number of the repeating unit, there is a progressive lowering in HOMO–LUMO gaps, being consistent with the red shifts in the lowest-lying absorptions and fluorescence. The ionization potentials (IPs) and electron affinities (EAs) of the polymer are obtained by the extrapolation method. The calculated IPs of DP-polymer are lower than those of P-polymer and the EAs of DP-polymer are higher than those of the P-polymer, which indicates that the DP-polymer is more suitable for electron transferring and hole creating material.

Novel roughness-controlled mannitol/LB Agar microparticles were synthesized by polymorphic transformation and self-assembly method using hexane as the polymorphic transformation reagent and spray-dried mannitol/LB Agar microparticles as the starting material. As-prepared microparticles were characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction spectra (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and Andersen Cascade Impactor (ACI). The XRD and DSC results indicate that after immersing spray-dried mannitol/LB Agar microparticles in hexane, β-mannitol was completely transformed to α-mannitol in 1 h, and all the δ-mannitol was transformed to α form after 14 days. SEM shows that during the transformation the nanobelts on the spray-dried mannitol/LB Agar microparticles become more dispersed and the contour of the individual nanobelts becomes more noticeable. Afterward, the nanobelts self-assemble to nanorods and result in rod-covered mannitol/LB Agar microparticles. FTIR indicates new hydrogen bonds were formed among mannitol, LB Agar, and hexane. SEM images coupled with image analysis software reveal that different surface morphology of the microparticles have different drug adhesion mechanisms. Comparison of ACI results and image analysis of SEM images shows that an increase in the particle surface roughness can increase the fine particle fractions (FPFs) using the rod-covered mannitol microparticles as drug carriers. Transformed microparticles show higher FPFs than commercially available lactose carriers. An FPF of 28.6 ± 2.4% was achieved by microparticles transformed from spray-dried microparticles using 2% mannitol(w/v)/LB Agar as feed solution. It is comparable to the highest FPF reported in the literature using lactose and spray-dried mannitol as carriers. ASTAR (Agency for Sci., Tech. and Research, S’pore) Accepted version

The series of iridium(III) complexes Ir(C^N) 2 LX (C^N = bzq, LX = acac, 1; CAN = thp, LX = acac, 2; C^N = tpy, LX = acac, 3; C^N = bzq, LX = dbm, 4; acac = acetoylacetonate, bzq = benzoquinoline, tpy = 2-(4-tolyl)pyridine, thp = 2-(2'-thienyl)pyridine and dbm = dibenzoylmethanate) have been investigated theoretically to explore their electronic structures and spectroscopic properties. Their structures in the ground and excited states have been optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels, respectively. The calculated bond lengths of Ir-N, Ir-C, and Ir-O in the ground state agree well with the corresponding experimental results. Upon excitation, the bond lengths of Ir-N and Ir-C lengthen by 0.03 A and that of Ir-O shortens by 0.01 A compared with those in the X 1 A ground states. This is consistent with the variation trend of corresponding vibration mode in the ground and excited states. At the TD-DFT and PCM levels, 1-4 give rise to absorptions at 484, 462, 452, and 536 nm and phosphorescent emissions at 541, 589, 499, and 540 nm, respectively. The transitions of 1-3 are attributed to [d(Ir) + π(C^N)] →[π*(C^N)] charge transfer, whereas those of 4 are related to [d(Ir) + π(C^N)] → [π*(LX) + π*(CAN)]. It is shown that the emissions are significantly dominated by the metal participating in the frontier molecular orbitals and affected by the C^N ligands but are hardly perturbed by the LX ligands.

Four new complexes [Zn(H2biim)2(H2O)2](Hbdc)2·(H2biim)·2H2O (1), [Zn(H2biim)2(H2O)](bdc)·CH3OH (2), [Co(H2biim)2(H2O)2](Hbtc)·4H2O (3) and [Cd(H2biim)2(H2O)(bdc)]·H2O (4) (where H2biim = 2,2′-biimidazole, bdc = 1,3-benzenedicarboxylate and btc = 1,3,5-benzenetricarboxylate) have been synthesized and characterized by single-crystal X-ray diffraction. The [M(H2biim)2(H2O) n ]2+ building blocks are assembled with carboxylates via charge-assisted N–H···O and O–H···N hydrogen bonds (N···O = 2.607 ∼ 2.926 A, ∠N–H–O = 151 ∼ 176°) into 1-D ribbons (1–3) and 3-D network (4). The ribbons are further arranged into 3-D networks via hydrogen bonds between carboxylate and water molecules as well as the free H2biim molecule (1) or methanol molecule (2). In complex 2, the CH3OH molecules are clathrated in the cavities. The results show that three robust heteromeric hydrogen-bonded synthons, namely and can be exploited to assemble the [M(H2biim)2(H2O) n ]2+ (M = Cd, Co and Zn, n = 1, 2) building blocks with dicarboxylates...

Cocrystallizations of melamine (MA) with 1,5-naphthalenedisulfonic acid (H2NDA) from water in different molar ratios (2:1, 4:1, and 8:1) offer [(HMA+)2(NDA2-)]·4H2O (1), [(HMA+)2(MA)2(NDA2-)]·8H2O (2), and [(HMA+)2(MA)2(NDA2-)]·10H2O (3), respectively. Among them, sulfonic protons are transferred to the triazine nitrogen atoms of MA, furnishing hydrogen-bonded anionic [(NDA2-)·H2O]∞ chains. In 1, the adjacent HMA+ cations form cationic (HMA+)∞ ribbons via pairs of N−H···N hydrogen bonds ( (8) synthon), and the ribbons connect to each other through NDA2- anions as well as lattice water molecules via hydrogen bonds and C−H···π, π···π, and electrostatic interactions to form a 3D structure. In 2 and 3, only half of the MA molecules are protonated, resulting in cationic (MA·HMA+)∞ ribbons via N−H···N hydrogen bonds. In 2, hydrophilic channels (size 3.9 × 6.1 A2) enclosed by the NDA2- anions and (MA·HMA+) cations are found to host a pair of zigzag water chains, which are interlinked through sulfonate oxygen ato...

The new complex [Cd2(bpa)2Cl4]·6 H2O [bpa = N,N'-bis(picolinamide)azine] has been synthesized in which each bpa ligand is twisted into a spiral-like conformation and the two CdII ions are ligated by two bpa ligands to form a double-stranded binuclear helicate. Unprecedented water chains featuring cyclic water tetramers composed of three independent water molecules are trapped by [Cd2(bpa)2Cl4] double helicates by hydrogen bonds. The binuclear chiral helicates are interlinked into homochiral layers by hydrogen bonds with the water tapes. The layers are alternately stacked in a heterochiral fashion to yield the final racemic structure. The complex shows an endotherm at 65.7 °C in the DSC due to loss of water molecules, giving an enthalpy value of 47 kJ mol–1 per water molecule. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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) A, V = 7044(6) A3, Z = 16; 2 in the monoclinic space group P21/c with a = 7.262(1), b = 21.970(2), c = 10.051(1) A, β = 105.01(1)°, V = 1548.8(2) A3, 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.

This review provides an overview on the crystal structures and properties of metal carboxylate coordination compounds with 2,2′-bipyridyl-like ligands reported in the past 4 years, which exhibit interesting structural features. This covers coordination polymers in one, two and three dimensions, as well as molecular architectures assembled by hydrogen-bonding and/or π–π stacking interactions from low-dimensional entities to higher-dimensional supramolecular architectures.

Three new complexes of [Co(H2biim)2(1,2-bdc)] (1), [Cd(H2biim)(1,3-bdc)]2 (2), and [Cd3(H2biim)2(1,4-bdc)3]·2H2O (3) (bdc = benzenedicarboxylate, H2biim = 2,2‘-biimidazole) have been synthesized and characterized by single-crystal X-ray diffraction. Complex 1 exhibits a 2-D herringbone architecture with mononuclear building blocks assembled via a robust hydrogen-bonded synthon R22(9). The homo- and heterochiral assemblies were observed in 1 between the H2biim ligand and carboxylate group via single and double hydrogen-bonded synthons R22(9). Complex 2 is a ribbonlike polymer based on a binuclear unit, and the ribbons are alternately decorated by H2biim ligands on both sides and further packed through intercalation of the lateral H2biim ligands and hydrogen bonds between the H2biim and carboxylate oxygen atoms into 2-D networks. These layers extend into a 3-D architecture via π−π stacking interactions. Complex 3 is a 3-D coordination polymer with a α-Po net topology based on linear trinuclear {Cd3O14N4} cl...

The weak metal-metal interactions of Pt(II)-Ag(I)/Cu(I) have been investigated by ab initio method at MP2 level through the model complexes [trans-Pt(PH3)2(CN)2-M(PH3)2+] (M=Ag,Cu). The calculated interaction energy of 12.9 and 11.5 kcal mol(-1) for [trans-Pt(PH3)2(CN)2-Ag(PH3)2+] and [trans-Pt(PH3)2(CN)2-Cu(PH3)2+] respectively, are in the middle of the van der Waals force and the strong hydrogen bond. The estimated equilibrium separations between Pt and M, r(eq)(Pt-M) (3.32 A for M=Ag and 3.23 A for M=Cu), lie within the region expected for weak metal-metal interaction. The electronic dispersive contributions dominate the weak interaction.

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)A, V = 1279.6(2)A3, and Z = 2. Each Pb(II) atom is eight-coordinated in a square-antiprismatic D4d 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. Hydrothermale Synthese und Kristallstruktur eines neuen polymeren oxalatverbruckten Blei(II)-Komplexes {[Pb(phen)2(ox)]·5H20}n (phen = 1, 10-Phenanthrolin, ox = Oxalat) Eine neue eindimensional-polymere, neutrale Koordinationsverbindung, {[Pb(phen)2(ox)]·5H20}n (phen = 1, 10-Phenanthrolin, ox = Oxalat) (1), wurde unter hydrothermalen Bedingungen synthetisiert und durch Rontgen-Kristallstrukturanalyse charakterisiert. 1 kristallisiert orthorhombisch, Raumgruppe Pban (No. 50) mit a = 19.358(2), b = 6.8135(6), c = 9.7015(8)A, V = 1279.6(2)A3, Z = 2. Jedes Blei(II)-Atom ist achtfach koordiniert in quadratisch-antiprismatischer D4d-Geometrie von vier Stickstoffatomen der zwei Phen-Gruppen und vier Sauerstoffatomen der zwei Oxalat-Liganden. Die polymeren Ketten bilden durch starke π—π-Wechselwirkungen und Wasserstoffbruckenbindungen ein dreidimensionales Gerust. Der Komplex zeigt intensiv-blaue Photolumineszens mit einem Emissionsmaximum von 403 nm bei Zimmertemperatur.

Five new silver(I) complexes with dimeric units, namely [Ag2(bib)2](BrO3)21, [Ag2(bib)2](ClO3)22, [Ag2(bib)2](ClO4)23, [Ag2(bib)2](NO3)2·2H2O 4 and [Ag2(bib)2(SCN)2] 5 (bib = 1,3-bis(4,5-dihydro-1H-imidazol-2-yl)benzene), have been synthesized and characterized by X-ray diffraction to observe the influence of the counter anions on crystal structures. Each bib acts as a bidentate ligand and every two bib ligands ligate a pair of Ag(I) ions resulting in a [2∶2] metallomacrocyclic motif that is further stabilized by intracyclic π–π interactions. 3 exhibits a dimeric structure, while 1, 2 and 4 are 1-D coordination polymers extended via interconnection of the dimeric units by the oxygen atoms from XO3− (X = Br and Cl) anions or Ag(I)⋯Ag(I) interactions. In 5, each Ag(I) ion is four-coordinate, and each dimeric unit is linked to the four adjacent dimeric units by four μ-sulfur atoms from SCN− groups into 2-D layer and further packed in 3-D network via hydrogen bonds. The photoluminescent properties of 1–4 have been observed in the solid state and dichloromethane solution at room temperature. The possible emission mechanisms have been proposed based on molecular orbital (MO) calculations.

Two new linear and V-shaped tetradentate ligands, namely 1,4-bis(2-hexahydropyrimidyl)benzene (L) and 1,3-bis(2-hexahydropyrimidyl)benzene (L′), and their silver(I) complexes, [Ag2L(μ-ONO2)](NO3) · 2H2O (1), [Ag2L(μ-pn)](NO3)2 (2), [Ag2L(μ-pn)](ClO4)2 (3) and [Ag4L′2(H2O)](NO3)4 · 5H2O (4) (pn=1,3-diaminopropane) have been synthesized in situ and structurally characterized by single-crystal X-ray diffraction. 1 and 2 were obtained from the same reaction solution but different crystallization conditions. 1 is an one-dimensional chain featuring cuboid tetranuclear silver(I) units interconnected through monoatomic nitrate bridges. Both 2 and 3 are ribbon-like helical compounds in which each L ligand acts in a tetradentate bridging mode to interconnect four metal atoms, and each pn ligand functions in a bidentate bridging mode to link a pair of metal atoms. 4 shows a truncated square-pyramidal tetranuclear motif arose by the V-shaped L′ ligand. Close Ag⋯Ag separations (2.901–2.939 A) assisted by bis(hexahydropyrimidine) bridges were observed in 1 and 4, indicating metal–metal interactions. Photoluminescence of 1–4 has also been observed in the solid state and solution at room temperature and low temperature, respectively.

Two new neutral polymeric layer compounds, [Cu3(bpy)2(Hip)2(ip)2] (1) and [Cu3(phen)2(Hip)2(ip)2] (2) (bpy = 2, 2′-bipyridine, phen = 1, 10-phenanthroline, ip = isophthalate), have been synthesized under hydrothermal conditions and characterized by X-ray crystallography. Complex 1 crystallizes triclinic, P1¯ (No. 2), a = 10.352(5), b = 10.859(6), c = 11.602(6)A, α = 83.25(1), β = 84.71(1), γ = 66.19(1)°, V = 1183.5(11)A3, Z = 1; 2 triclinic, P1¯ (No. 2), a = 10.375(1), b = 10.668(1), c = 11.758(1)A, α = 83.179(2), β = 86.228(2), γ = 71.187(2)°, V = 1222.7(2)A3, Z = 1. The complexes consist of trinuclcear copper units that are bridged via two ip ligands forming zigzag polymeric chains. These chains are further extended into layers via aromatic π-π interactions as well as hydrogen bonds between the free carboxyl groups and carboxylates. Synthese und strukturelle Charakterisierung von zwei neuen 2D-Isophthalatverbruckten Kupfer(II)-Polymeren mit Cu3-Einheiten Zwei neue polymere Schichtverbindungen, [Cu3(bpy)2(Hip)2(ip)2] (1) und [Cu3(phen)2(Hip)2(ip)2] (2) (bpy = 2, 2′-bipyridin, phen = 1, 10-phenanthrolin, ip = isophthalat), wurden unter hydrothermalen Bedingungen synthetisiert und mittels Rontgen-Kristallstrukturanalyse charakterisiert. Complex 1 kristallisiert triklin, P1¯ (No. 2), a = 10.352(5), b = 10.859(6), c = 11.602(6)A, α = 83.25(1), β = 84.71(1), γ = 66.19(1)°, V = 1183.5(11)A3, Z = 1; 2 triklin, P1¯ (No. 2), a = 10.375(1), b = 10.668(1), c = 11.758(1)A, α = 83.179(2), β = 86.228(2), γ = 71.187(2)°, V = 1222.7(2)A3, Z = 1. Die Komplexe bestehen aus dreikernigen Kupfer-Einheiten, die uber zwei ip-Liganden unter Bildung von polymeren zick-zack-Ketten verbruckt sind. Diese Ketten bilden Schichten uber aromatische π-π-Wechselwirkungen und Wasserstoffbruckenbindungen zwischen den freien Carboxyl-Gruppen und Carboxylaten.

X-ray structural and spectroscopic properties of a series of heterodinuclear d8−d10 metal complexes [M‘M‘ ‘(μ-dcpm)2(CN)2]+ containing d8 Pt(II), Pd(II), or Ni(II) and d10 Au(I), Ag(I), or Cu(I) ions with a dcpm bridging ligand have been studied (dcpm = bis(dicyclohexylphosphino)methane; M‘ = Pt, M‘ ‘ = Au 4, Ag 5, Cu, 6; M‘ ‘ = Au, M‘ = Pd 7, Ni 8). X-ray crystal analyses showed that the metal···metal distances in these heteronuclear metal complexes are shorter than the sum of van der Waals radii of the M‘ and M‘ ‘ atoms. The UV−vis absorption spectra of 4−6 display red-shifted intense absorption bands from the absorption spectra of the mononuclear trans-[Pt(phosphine)2(CN)2] and [M‘ ‘(phosphine)2]+ counterparts, attributable to metal−metal interactions. The resonance Raman spectra confirmed assignments of 1[ndσ*→(n + 1)pσ] electronic transitions to the absorption bands at 317 and 331 nm in 4 and 6, respectively. The results of theoretical calculations at the MP2 level reveal an attractive interaction en...

Structural and spectroscopic properties of and theoretical investigations on dinuclear [Pd 2 (CN) 4 (P-P) 2 ] (P - P = bis(dicyclohexylphosphanyl)methane (1), bis(dimethylphosphanyl)methane (2)) and mononuclear trans[Pd(CN) 2 (PCy 3 ) 2 ] (3) complexes are described. X-ray structural analyses reveal Pd...Pd distances of 3.0432(7) and 3.307(4) A in 1 and 2, respectively. The absorption bands at λ > 270 nm in 1 and 2 have 4d* σ → 5p σ electronic-transition character. Calculations at the CIS level indicate that the two low-lying dipole-allowed electronic transition bands in model complex [Pd 2 (CN) 4 (μ-H 2 PCH 2 PH 2 ) 2 ] at 303 and 289 nm are due to combinations of many orbital transitions. The calculated interaction-energy curve for the skewed dimer [{trans[Pd(CN) 2 (PH 3 ) 2 ]} 2 ] is attractive at the MP2 level and implies the existence of a weak Pd I I -Pd I I interaction.