Ming-Jian Zhang

Inorganic Supramolecular Compounds with 3-D Chiral Frameworks Show Potential as Both Mid-IR Second-Order Nonlinear Optical and Piezoelectric Materials

Two inorganic supramolecular compounds, (Hg(6)P(3))(In(2)Cl(9)) (1) and (Hg(8)As(4))(Bi(3)Cl(13)) (2), which have chiral 3-D host frameworks with guest moieties filling the helical tunnels, have been synthesized. They both have large second-harmonic generation efficiencies, and compound 2 also exhibits obvious single-crystal piezoelectric performance. Theoretical studies from first-principles calculations were performed on their nonlinear optical (NLO) and piezoelectric properties, and results indicate that good NLO and piezoelectric materials can be obtained by designing both complicated polycations and polyanions with large molecular polarizability as functional components rather than traditional single polyanions.

A highly luminescent chameleon: fine-tuned emission trajectory and controllable energy transfer

By varying the stoichiometric ratio of Eu3+, Tb3+ and Gd3+ ions in a lanthanide metal–organic framework, a mixed-Ln MOF, [Eu0.0040Tb0.0460Gd0.9500(BTB)(DMSO)2]·H2O, has been designed to display white-light emission. In addition, the switch between blue, white, and yellow for this material has been achieved by controlling the energy transfer process.

Electron‐Transfer Photochromism To Switch Bulk Second‐Order Nonlinear Optical Properties with High Contrast

The first bulk electron-transfer photochromic compound with intrinsic second-order nonlinear optical (NLO) photoswitching properties has been synthesized. This system employs an electron-transfer photoactive asymmetric viologen ligand coordinated to a zinc(II) center.

Homochiral Zinc(II) Coordination Compounds Based on In-Situ-Generated Chiral Amino Acid–Tetrazole Ligands: Circular Dichroism, Excitation Light-Induced Tunable Photoluminescence, and Energetic Performance

We employed two pairs of new in-situ-generated chiral amino acid-tetrazole ligands in constructing homochiral Zn(II) coordination compounds: [Zn(tzet)]n (1a for (S)-tzet and 1b for (R)-tzet, H2tzet = N-[2-(1H-tetrazol-5-yl)ethyl]tryptophan) and [Zn(tzep)(H2O)2]·H2O (2a for (S)-tzep and 2b for (R)-tzep, H2tzep = N-[2-(1H-tetrazol-5-yl)ethyl]proline), which were hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Structural analysis reveals that 1 features a 2D homochiral framework generated by both tetrazolate and carboxylate bridges in tzet(2-) ligands. The isolated structure of 2 is stabilized by extensive hydrogen bonds, which leads to formation of a supramolecular 2D architecture. The absolute configuration induced at the nitrogen atoms of 1 and 2 is strictly related to the neighboring chiral carbon atoms by hydrogen-bond interactions. To further investigate their chirality, the combined experimental and theoretical analyses of circular dichroism spectra reveal the absolute configurations and nature of the Cotton effects. Solid-state excitation and emission spectra for 1 and 2 at room temperature were investigated with relevant density of states calculation, and tunable photoluminescence emission of 1 under different excitation wavelengths was discussed. As nitrogen-rich tetrazolate compounds, 1 and 2 possess higher enthalpies of combustion and may serve as a new family of promising energetic materials.

Two phases of Ga2S3: promising infrared second-order nonlinear optical materials with very high laser induced damage thresholds

Two phases of Ga2S3 with different space groups Cc and F3m were synthesized in pure phase by a facile boron–sulfur–metallic oxide reaction. They both have a good transparency in the wavelength range of 0.44–25 μm and exhibit comparatively large second-harmonic generation (SHG) effects of about 0.7 and 0.5 times that of commercial KTiOPO4 (KTP), for the monoclinic and cubic Ga2S3 respectively. The monoclinic Ga2S3 is phase-matchable at the wavelength of 1910 nm while the cubic phase is non-phase-matchable. In order to study their powder laser induced damage threshold (LIDT) properties, a single pulse powder LIDT measurement method was proposed and it was found that they have very high powder LIDTs of about 30 and 100 times that of AgGaS2 (AGS), respectively for the monoclinic and cubic phase, under a single pulse 1064 nm laser radiation with a pulse width τp of 8 ns. To gain further insights into the nonlinear optical (NLO) and LIDT properties of the monoclinic and cubic Ga2S3, calculations of second-order NLO susceptibility and lattice energy density (LED) were also performed to explain their SHG efficiencies and high LIDTs.

Different effects of a cotemplate and [(transition-metal)(1,10-phenanthroline)(m)]2+ (m = 1-3) complex cations on the self-assembly of a series of hybrid selenidostannates showing combined optical properties of organic and inorganic components.

1,10-Phenanthroline (phen) and monoprotonated methylamine molecules were used as a novel cotemplate to direct the formation of a new inorganic-organic hybrid selenidostannate, (CH(3)NH(3))(4)(Sn(2)Se(6))·6phen (1); while the utilization of three types of transition-metal (TM) phen complex cations with the TM/phen ration of 1:1, 1:2, and 1:3 as structure directors affords {[Mn(phen)(2)](2)(μ(2)-Sn(2)Se(6))}·H(2)O (2a), {[Fe(phen)(2)](2)(μ(2)-Sn(2)Se(6))} (2b), {[Mn(phen)](2)(μ(4)-Sn(2)Se(6))}(n) (3), {[Mn(phen)(2)](Sn(2)Se(5))}(n) (4), and [Fe(phen)(3)](n)(Sn(3)Se(7))(n)·1.25nH(2)O (5). These compounds show diverse structures with the selenidostannate anions varying from discrete, μ(2)- and μ(4)- (Sn(2)Se(6))(4-) anions, to one-dimensional (1-D) (1)(∞)(Sn(2)Se(5)(2-)) anionic chains, and two-dimensional (2-D) extended (2)(∞)(Sn(3)Se(7)(2-)) anionic layers, demonstrating different structure-directing abilities of the cotemplate and the three types of TM phen complex cations. This work clearly indicates that the approach of modifying the number of the free coordination sites of unsaturated TM phen complex cations is very exciting as a way to synthesize novel hybrid chalcogenidometalates. Of particular interest, the present compounds exhibit interesting optical properties that reflect the combined effects of both photoluminescence-active organic components and semiconducting inorganic chalcogenidometalate anionic networks.

Syntheses, Structures, and Nonlinear-Optical Properties of Metal Sulfides Ba2Ga8MS16 (M = Si, Ge)

Two new metal sulfides, Ba(2)Ga(8)MS(16) (M = Si, Ge), have been synthesized by high-temperature solid-state reactions. They are isostructural and crystallize in the noncentrosymmetric space group P6(3)mc (No. 186) with a = 10.866(5) Å, c = 11.919(8) Å, and z = 2 for Ba(2)Ga(8)SiS(16) (1) and a = 10.886(8) Å, c = 11.915(3) Å, and z = 2 for Ba(2)Ga(8)GeS(16) (2). Their three-dimensional frameworks are constructed by corner-sharing mixed (Ga/M)S(4) (M = Si, Ge) and pure GaS(4) tetrahedra, with Ba(2+) cations filling in the tunnels. Compounds 1 and 2 are transparent over 0.42-20 μm and have wide band gaps of around 3.4 and 3.0 eV, respectively. Polycrystalline 2 displays strong nonlinear second-harmonic-generation (SHG) intensities that are comparable to that of the benchmark AgGaS(2) (AGS) with phase-matching behavior at a laser irradiation of 1950 nm. Of particular interest, compound 2 also possesses a high powder laser-induced damage threshold of ∼22 times that of AGS. The alternate stacking of the mixed (Ga/M)S(4) (M = Si, Ge) tetrahedral layer with the pure GaS(4) tetrahedral layer along the c axis and the alignment of these two types of tetrahedra in the same direction may be responsible for the large SHG signals observed.

Syntheses, Structures, and Nonlinear Optical Properties of Two Sulfides Na2In2MS6 (M = Si, Ge)

The first two new Na-containing sulfides Na₂In₂MS₆ (M = Si (1), Ge (2)) in the Na₂Q-B₂Q₃-CQ₂ (B = Ga, In; C = Si, Ge, Sn; Q = S, Se) system were prepared for the first time through conventional high-temperature solid-state reaction. They are isostructural with space group Cc (No. 9) in monoclinic phases and feature three-dimensional frameworks built by the (∞)¹[In₂MS₆]²⁻ (M = Si, Ge) chains through corner-sharing InS₄ tetrahedra and MS₄ (M = Si, Ge) tetrahedra, with Na⁺ cation located in the cavities. They display moderate second harmonic generation (SHG) conversion efficiencies compared with commercial AgGaS₂, with phase-matching behavior at 1800 nm and laser-induced damage thresholds 6.9 and 4.0 times higher than that of AgGaS₂, respectively. Therefore, the output SHG intensities of 1 and 2 will be ∼4.3 and 4.0 times larger than that of AgGaS₂, when the intensity of incident laser increased to close the damage energy of 1 and 2, indicating their potential for high-power nonlinear optical application.

A highly stable 3D acentric zinc metal-organic framework based on two symmetrical flexible ligands: high second-harmonic-generation efficiency and tunable photoluminescence.

A 3D metal-organic framework (MOF), [Zn(BPHY)(SA)]n (1; BPHY = 1,2-bis(4-pyridyl)hydrazine, H2SA = succinic acid), which crystallizes in a noncentrosysmmetric space group (Cc), has been solvothermally obtained and testified to be a good nonlinear-optical material with the largest second-harmonic-generation response among the known MOFs based on sysmmetric ligands and high stability. Ultraviolet-to-visible tunable emission for 1 is observed.

Crystal structures and optical properties of iodoplumbates hybrids templated by in situ synthesized 1,4-diazabicyclo[2.2.2]octane derivatives

We investigate the impact of different derivatives of 1,4-diazabicyclo[2.2.2]octane on the crystal structures of iodoplumbates by systematically increasing the size of the same organic amine, and present two new 1-D iodoplumbates. Optical studies reveal the semiconductor characteristics of all as-synthesized iodoplumbate hybrids.