P∩N Bridged Cu(I) Dimers Featuring Both TADF and Phosphorescence. From Overview towards Detailed Case Study of the Excited Singlet and Triplet States.

We present an overview over eight brightly luminescent Cu(I) dimers of the type Cu2X2(P∩N)3 with X = Cl, Br, I and P∩N = 2-diphenylphosphino-pyridine (Ph2Ppy), 2-diphenylphosphino-pyrimidine (Ph2Ppym), 1-diphenylphosphino-isoquinoline (Ph2Piqn) including three new crystal structures (Cu2Br2(Ph2Ppy)3 1-Br, Cu2I2(Ph2Ppym)3 2-I and Cu2I2(Ph2Piqn)3 3-I). However, we mainly focus on their photo-luminescence properties. All compounds exhibit combined thermally activated delayed fluorescence (TADF) and phosphorescence at ambient temperature. Emission color, decay time and quantum yield vary over large ranges. For deeper characterization, we select Cu2I2(Ph2Ppy)3, 1-I, showing a quantum yield of 81%. DFT and SOC-TDDFT calculations provide insight into the electronic structures of the singlet S1 and triplet T1 states. Both stem from metal+iodide-to-ligand charge transfer transitions. Evaluation of the emission decay dynamics, measured from 1.2 ≤ T ≤ 300 K, gives ∆E(S1-T1) = 380 cm-1 (47 meV), a transition rate of k(S1→S0) = 2.25 × 106 s-1 (445 ns), T1 zero-field splittings, transition rates from the triplet substates and spin-lattice relaxation times. We also discuss the interplay of S1-TADF and T1-phosphorescence. The combined emission paths shorten the overall decay time. For OLED applications, utilization of both singlet and triplet harvesting can be highly favorable for improvement of the device performance.

Crystal structure of 1-((1E)-{(E)-2-[(2-hydroxy-naphthalen-1-yl)methyl-idene]hydrazin-1-yl-idene}meth-yl)naphthalen-2-ol.

The complete mol-ecule of the title compound, C22H16N2O2, is generated by a crystallographic inversion centre at the mid-point of the central N-N bond. Two intra-molecular O-H⋯N hydrogen bonds occur.

A series of M(II)Cu(II)3 stars (M = Mn, Ni, Cu, Zn) exhibiting unusual magnetic properties.

The work in this report describes the syntheses, electrospray ionization mass spectromtery, structures, and experimental and density functional theoretical (DFT) magnetic properties of four tetrametallic stars of composition [M(II)(Cu(II)L)3](ClO4)2 (1, M = Mn; 2, M = Ni; 3, M = Cu; 4, M = Zn) derived from a single-compartment Schiff base ligand, N,N'-bis(salicylidene)-1,4-butanediamine (H2L), which is the [2 + 1] condensation product of salicylaldehyde and 1,4-diaminobutane. The central metal ion (Mn(II), Ni(II), Cu(II), or Zn(II)) is linked with two µ2-phenoxo bridges of each of the three [Cu(II)L] moieties, and thus the central metal ion is encapsulated in between three [Cu(II)L] units. The title compounds are rare or sole examples of stars having these metal-ion combinations. In the cases of 1, 3, and 4, the four metal ions form a centered isosceles triangle, while the four metal ions in 2 form a centered equilateral triangle. Both the variable-temperature magnetic susceptibility and variable-field magnetization (at 2-10 K) of 1-3 have been measured and simulated contemporaneously. While the Mn(II)Cu(II)3 compound 1 exhibits ferromagnetic interaction with J = 1.02 cm(-1), the Ni(II)Cu(II)3 compound 2 and Cu(II)Cu(II)3 compound 3 exhibit antiferromagnetic interaction with J = -3.53 and -35.5 cm(-1), respectively. Variable-temperature magnetic susceptibility data of the Zn(II)Cu(II)3 compound 4 indicate very weak antiferromagnetic interaction of -1.4 cm(-1), as expected. On the basis of known correlations, the magnetic properties of 1-3 are unusual; it seems that ferromagnetic interaction in 1 and weak/moderate antiferromagnetic interaction in 2 and 3 are possibly related to the distorted coordination environment of the peripheral copper(II) centers (intermediate between square-planar and tetrahedral). DFT calculations have been done to elucidate the magnetic properties. The DFT-computed J values are quantitatively (for 1) or qualitatively (for 2 and 3) matched well with the experimental values. Spin densities and magnetic orbitals (natural bond orbitals) correspond well with the trend of observed/computed magnetic exchange interactions.

Femtomolar level sensing of inorganic arsenic(III) in water and in living-systems using a non-toxic fluorescent probe.

A highly selective femtomolar level sensing of inorganic arsenic(III) as arsenious acid has been accomplished in water medium and in living-systems (on pollen grains of Tecoma stans; Candida albicans cells (IMTECH No. 3018) and Peperomia pellucida stem section) using a non-toxic fluorescent probe of a Cu(II)-complex.

Diaquaiodidotetrasarcosinepotassium: an overview of sarcosine metal halogenide structures.

The monoclinic crystal structure of tetrasarcosine potassium iodide dihydrate {or catena-poly[[potassium-tetra-µ-sarcosine-κ(4)O:O';κ(4)O:O] iodide dihydrate]}, {[K(C(3)H(7)NO(2))(4)]I·2H(2)O}(n) or Sar(4)·KI·2H(2)O (space group C2/c), comprises two crystallographically different sarcosine molecules and one water molecule on general positions, and one K(+) cation and one I(-) anion located on twofold axes. The irregular eight-coordinated K(+) polyhedra are connected into infinite chains along [001] via sarcosine molecules. This compound is the first sarcosine metal halogenide salt with a 4:1 ratio. A short overview of other sarcosine metal halogenide salts is presented and relationships to similar glycine salts are discussed.

Syntheses, crystal structures, reactivity, and photochemistry of gold(III) bromides bearing N-heterocyclic carbenes.

Gold(I) complexes bearing N-heterocyclic carbenes (NHC) of the type (NHC)AuBr (3a/3b) [NHC = 1-methyl-3-benzylimidazol-2-ylidene (= MeBnIm), and 1,3-dibenzylimidazol-2-ylidene (= Bn(2)Im)] are prepared by transmetallation reactions of (tht)AuBr (tht = tetrahydrothiophene) and (NHC)AgBr (2a/2b). The homoleptic, ionic complexes [(NHC)(2)Au]Br (6a/6b) are synthesized by the reaction with free carbene. Successive oxidation of 3a/3b and 6a/6b with bromine gave the respective (NHC)AuBr(3) (4a/4b) and [(NHC)(2)AuBr(2)]Br (7a/7b) in good overall yields as yellow powders. All complexes were characterized by NMR spectroscopy, mass spectrometry, elemental analysis and single crystal X-ray diffraction. Reactions of the Au(III) complexes towards anionic ligands like carboxylates, phenolates and thiophenolates were investigated and result in a complete or partial reduction to a Au(I) complex. Irradiation of the Au(III) complexes with UV light yield the Au(I) congeners in a clean photo-reaction.

Slow magnetic relaxation and electron delocalization in an S = 9/2 iron(II∕III) complex with two crystallographically inequivalent iron sites.

The magnetic, electronic, and Mössbauer spectral properties of [Fe(2)L(µ-OAc)(2)]ClO(4), 1, where L is the dianion of the tetraimino-diphenolate macrocyclic ligand, H(2)L, indicate that 1 is a class III mixed valence iron(II∕III) complex with an electron that is fully delocalized between two crystallographically inequivalent iron sites to yield a [Fe(2)](V) cationic configuration with a S(t) = 9∕2 ground state. Fits of the dc magnetic susceptibility between 2 and 300 K and of the isofield variable-temperature magnetization of 1 yield an isotropic magnetic exchange parameter, J, of -32(2) cm(-1) for an electron transfer parameter, B, of 950 cm(-1), a zero-field uniaxial D(9∕2) parameter of -0.9(1) cm(-1), and g = 1.95(5). In agreement with the presence of uniaxial magnetic anisotropy, ac susceptibility measurements reveal that 1 is a single-molecule magnet at low temperature with a single molecule magnetic effective relaxation barrier, U(eff), of 9.8 cm(-1). At 5.25 K the Mössbauer spectra of 1 exhibit two spectral components, assigned to the two crystallographically inequivalent iron sites with a static effective hyperfine field; as the temperature increases from 7 to 310 K, the spectra exhibit increasingly rapid relaxation of the hyperfine field on the iron-57 Larmor precession time of 5 × 10(-8) s. A fit of the temperature dependence of the average effective hyperfine field yields |D(9∕2)| = 0.9 cm(-1). An Arrhenius plot of the logarithm of the relaxation frequency between 5 and 85 K yields a relaxation barrier of 17 cm(-1).

Spectroscopic properties of guanidinium zinc sulphate [C(NH2)3]2Zn(SO4)2 and ab initio calculations of [C(NH2)3]2 and HC(NH2)3.

Raman and FTIR spectra of guanidinium zinc sulphate [C(NH(2))(3)](2)Zn(SO(4))(2) are recorded and the spectral bands assignment is carried out in terms of the fundamental modes of vibration of the guanidinium cations and sulphate anions. The analysis of the spectrum reveals distorted SO(4)(2-) tetrahedra with distinct S-O bonds. The distortion of the sulphate tetrahedra is attributed to Zn-O-S-O-Zn bridging in the structure as well as hydrogen bonding. The CN(3) group is planar which is expressed in the twofold symmetry along the C-N (1) vector. Spectral studies also reveal the presence of hydrogen bonds in the sample. The vibrational frequencies of [C(NH(2))(3)](2) and HC(NH(2))(3) are computed using Gaussian 03 with HF/6-31G* as basis set.

catena-Poly[[manganese(II)-tris-(µ-bet-aine-κO:O')] tetra-bromido-manganate(IV).

The title compound, [Mn(C(5)H(11)NO(2))(3)]·MnBr(4), contains polymeric cationic chains of distorted MnO(6) octa-hedra and bridging betaine mol-ecules, running parallel to the a axis. There are two distinct Mn(2+) cations in the chain, both with site symmetry . Distorted [MnBr(4)](2-) tetra-hedra occupy the spaces between the chains.

Orientational disorder of [Mg(H2O)6] octahedra in the novel magnesium selenite hydrate Mg(SeO3).7.5H2O.

The crystal structure of magnesium selenite 7.5-hydrate, Mg(SeO3).7.5H2O (space group P6(3)/mmc), is characterized by two crystallographically distinct [Mg(H2O)6]2+ octahedra, one of which is disordered over two different orientations. The selenite groups and water molecules (with partially disordered H atoms) bridge the octahedra via hydrogen bonds. All the atoms are located on special positions, except for one water molecule.

Compounds of glycine with metal sulfates and thiosulfates: glycine cobalt sulfate pentahydrate, glycine sodium thiosulfate dihydrate and glycine potassium thiosulfate.

In the crystal structures of the title compounds, hexaaquacobalt(II) tetraaquadiglycinatocobalt(II) bis(sulfate), [Co(H2O)6][Co(C2H5NO2)2(H2O)4](SO4)2, (I), poly[diaqua-mu3-glycinato-di-mu4-thiosulfato-tetrasodium(I)], [Na4(C2H5NO2)(S2O3)2(H2O)2]n, (II), and poly[mu2-glycinato-mu4-thiosulfato-dipotassium(I)], [K2(C2H5NO2)(S2O3)]n, (III), all atoms are located on general positions, except the Co atoms in (I), which are located on inversion centres. In (I), hydrogen bonds play an important role, while the alkali thiosulfate compounds are characterized by three-dimensional frameworks of polyhedra. Relations to other compounds of glycine and metal sulfates are commented on.

Two novel glycine metal halogenides: catena-poly[[[diaquanickel(II)]-di-mu-glycine] dibromide] and catena-poly[[[tetraaquamagnesium(II)]-mu-glycine] dichloride].

In catena-poly[[[diaquanickel(II)]-di-mu-glycine] dibromide], {[Ni(C2H5NO2)2(H2O)2]Br2}n, (I), the Ni atom is located on an inversion centre. In catena-poly[[[tetraaquamagnesium(II)]-mu-glycine] dichloride], {[Mg(C2H5NO2)(H2O)4]Cl2}n, (II), the Mg atom and the non-H atoms of the glycine molecule are located on a mirror plane. All other atoms are located on general positions. The atomic arrangements of both compounds are characterized by [MO6] octahedra (M=Ni or Mg) connected by glycine molecules, with the halogenide ions in the interstices. In (I), four of the coordinating O atoms are from glycine and two are from water molecules, building layers of octahedra and organic molecules. In (II), two of the coordinating O atoms are from glycine and four are from water molecules. The octahedra and organic molecules form chains.

Thiocyanates of nickel and caesium: Cs2NiAg2(SCN)6.2H2O and CsNi(SCN)3.

The crystal structures of dicaesium nickel disilver hexathiocyanate dihydrate, Cs2NiAg2(SCN)6.2H2O, (I), and caesium nickel trithiocyanate, CsNi(SCN)3, (II), have been determined by single-crystal X-ray diffraction at 273 K. Compounds (I) and (II) are monoclinic, with P21/c and P21/n symmetry, respectively. In (I), the Ni atom lies on an inversion centre; in (II), there are two independent Ni atoms, each of which lies on an inversion centre. The coordination polyhedra and the bonding schemes in the structures are discussed.

Three novel non-centrosymmetric compounds of glycine: glycine lithium sulfate, glycine nickel dichloride dihydrate and glycine zinc sulfate trihydrate.

The crystal structures of three compounds of glycine and inorganic materials are presented and discussed. The orthorhombic structure of glycinesulfatodilithium(I), [Li(2)(SO(4))(C(2)H(5)NO(2))](n), consists of corrugated sheets of [LiO(4)] and [SO(4)] tetrahedra. The glycine molecules are located between these sheets. The main features of the monoclinic structure of diaquadichloroglycinenickel(II), [NiCl(2)(C(2)H(5)NO(2))(H(2)O)(2)](n), are helical chains of [NiO(4)Cl(2)] octahedra connected by glycine molecules. The orthorhombic structure of triaquaglycinesulfatozinc(II), [Zn(SO(4))(C(2)H(5)NO(2))(H(2)O)(3)](n), is made up of [O(3)SOZnO(5)] clusters. These clusters are linked by glycine molecules into zigzag chains. All three compounds are examples of non-centrosymmetric glycine compounds.