Volume 72, Issue 2

The title compound is formed by a non-trivial reaction involving two molecules of the stable free radical 2,2-diphenyl-1-picryl-hydrazyl and one molecule of N -methoxy-picramide. We could now perform an X-ray diffraction experiment on a single crystal and can fully confirm the betaine structure which has a central quinonoid ring with alternating long and short bonds.

The synthesis and crystal structure of the rare earth borogermanate EuGeBO 5 are reported. It is synthesized by high-temperature solid-state reaction and crystallizes in the monoclinic space group P 2 1 / c (no. 14) with the unit cell parameters a =4.8860(5), b =7.5229(8), c =9.9587(10) Å, and β =91.709(3)°. Its crystal structure features a polyanion-type layer (GeBO 5 ) 3− constructed by BO 4 and GeO 4 tetrahedra connected alternatingly. Eu 3+ ions are located in cavities and are coordinated by eight O atoms. Various structures of the related compounds REMM ′O 5 ( RE =rare earth metal; M =Si, Ge, and Sn; M ′=B, Al, and Ga) are also discussed.

The reaction of [PPh 4 ] 2 [WS 4 ] in CH 3 CN with excess n -propylbromide or n -butylbromide gave alkylthiolatotrithiotungstate complexes, [PPh 4 ][WS 3 (SR)] ( 1 : R= n -propyl; 2 : R= n -butyl). The analogous reaction with 1-bromomethyl-4-chloromethyl-benzene afforded a benzylthiolatotrithiotungstate complex, [PPh 4 ][WS 3 (SCH 2 C 6 H 4 CH 2 Cl-4)] ( 3 ), whereas the reaction with 1,4-bis-bromomethyl-benzene led to isolation of a dinuclear complex [PPh 4 ] 2 [WS 3 ( μ -SCH 2 C 6 H 4 CH 2 S)WS 3 ] ( 4 ). Complexes 1–4 were characterized spectroscopically and the crystal structures of 1 / 2 ·½C 6 H 6 and 3 have been determined by X-ray diffraction.

Two isostructural fluorinated metal-organic frameworks, formulated as [ M 2 (Fbix)(1,4-NDC) 2 ] n ( M =Cd for 1 and Mn for 2 ), were synthesized by employing 1,4-naphthalenedicarboxylic acid (1,4-H 2 NDC) and the flexible fluorinated ligand 2,3,5,6-tetrafluoro-1,4-bis(imidazole-1-yl-methyl)benzene (Fbix) under hydrothermal conditions. Their structures were determined by single-crystal X-ray diffraction and further characterized by infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analyses. Structure analyses have revealed that compounds 1 and 2 show an unusual hex net based on infinite rod-shaped secondary building units. The solid-state fluorescence spectra of 1 and 2 were measured and indicate a ligand-based emission for both complexes.

In this work, a new macrocyclic copper complex, [Cu(ACE)(SCN) 2 ]; ACE: 1,3,6,10,12,15-hexaazatricyclo[13.3.1.1 6,10 ]eicosane, was prepared and characterized by elemental analysis, FT-IR, Raman spectroscopy and single-crystal X-ray diffraction. X-ray analysis of [Cu(ACE)(SCN) 2 ] reveals an elongated octahedral geometry around the copper atom in a centrosymmetric CuN 6 environment.

Development of catalysts for efficient conversion of lignin polymer to value-added materials requires appropriately-functionalized lignin model compounds. The predominant structural feature of lignin biopolymer is an extensive network of β -O-4 linkages. Access to large amounts of a model compound containing the β -O-4 linkage is crucial for the valorisation of lignin biopolymer to aromatic raw materials. Starting from commercially available vanillin, synthesis of dilignol model compound, containing a β -O-4 linkage, is accomplished in good overall yield.

Three new manganese(II) complexes, {[Mn(PTP)] 2 [Mn(PTP)(H 2 O)]}(BTA) 2 ·2H 2 O ( 1 ), [Mn(PTP)(ODA)] 2 ( 2 ), and [Mn(FTP)(ODA)] 2 ·H 2 O ( 3 ), were synthesized by the reactions of manganese acetate and polycarboxylic acid in the presence of N -heterocyclic ligands (where PTP=4′-phenyl-2,2′:6′,2″-terpyridine, H 3 BTA=benzene-1,3,5-tricarboxylic acid, H 2 ODA=4,4′-oxydibenzoic acid, FTP=4′-(furan-2-yl)-2,2′:6′,2″-terpyridine). In complex 1 , each BTA ligand serves as a μ 3 -bridge to link three Mn(II) centers, whereas each Mn(II) center is coordinated by two BTA ligands. This connection mode results in a grid sheet. Complexes 2 and 3 have very similar molecular structures with Mn(II) centers connected by ODA ligands to result in ring-like arrays. We investigated the third-order nonlinear optical (NLO) properties of the three complexes by single beam Z-scan techniques. Complexes 1 – 3 exhibit strong third-order NLO reverse saturable absorption with NLO absorptive indices β =1.32×10 −6 , 3.01×10 −6 , and 9.42×10 −6 m W −1 , respectively. In addition, complex 1 shows all excellent self-focusing effect with an NLO refractive index of γ =1.25×10 −12 m 2 W −1 . The third-order NLO susceptibility χ (3) of the three complexes were calculated as 47.55×10 −8 , 4.85×10 −8 , and 15.16×10 −8 esu, respectively.

A new trinuclear heterometallic complex, [(CuL)Na(CuL)]·ClO 4 ( 1 ), has been prepared using a Schiff base, H 2 L (where H 2 L= N , N ′-(1,2-phenylene)-bis(3-methoxysalicylideneimine) and characterized by elemental analysis, Fourier transform infra-red (FT-IR) spectroscopy, UV/Vis, magnetic, electrochemical, and single crystal X-ray diffraction methods. The structure analysis reveals that two metallo-ligand [(CuL)] units are connected to each other by a sodium ion resulting in the cationic unit [(CuL)Na(CuL)] + . Both the copper(II) ions display an almost square planar geometry while the sodium ion adopts a trigonal-dodecahedral coordination geometry. The spectroscopic and other physicochemical studies are in good agreement with the crystal structure of the complex.

The crystal structures of [C 2 H 5 NH 3 ] 4 InBr 7 ( 1 ), [C(NH 2 ) 3 ] 3 InBr 6 ( 2 ), and [H 3 NCH 2 C(CH 3 ) 2 CH 2 NH 3 ]InBr 5 ( 3 ) were determined at 100(2) K: monoclinic, P 2 1 /n , a =1061.94(3), b =1186.40(4), c =2007.88(7) pm, β = 104.575(1)°, Z =4 for 1 ; monoclinic, C 2/ c , a =3128.81(12), b =878.42(3), c =2816.50(10) pm, β =92.1320(10)°, Z =16 for 2 ; orthorhombic, P 2 1 2 1 2 1 , a =1250.33(5), b =1391.46(6), c =2503.22(9) pm, Z =4 for 3 . The structure of 1 contains an isolated octahedral [InBr 6 ] 3− ion and a Br − ion. The structure of 2 contains three different isolated octahedral [InBr 6 ] 3− ions. The structure of 3 has a corner-shared double-octahedral [In 2 Br 11 ] 5− ion and an isolated tetrahedral [InBr 4 ] − ion. The 81 Br nuclear quadrupole resonance (NQR) lines of the terminal Br atoms of the compounds are widely spread in frequency, and some of them show unusual positive temperature dependence. These observations manifest the N−H···Br−In hydrogen bond networks developed between the cations and anions to stabilize the crystal structures. The 81 Br NQR and differential thermal analysis (DTA) measurements have revealed the occurrence of unique phase transitions in 1 and 3 . When the bond angles were estimated from the electric field gradient (EFG) directions calculated by the molecular orbital (MO) methods, accurate values were obtained for [InBr 6 ] 3− of 1 and for [In 2 Br 11 ] 5− and [InBr 4 ] − of 3 , except for several exceptions in those for the latter two ions. On the other hand, the calculations of 81 Br NQR frequencies have produced up to 1.4 times higher values than the observed ones.

Li 3 Y(BO 3 ) 2 was prepared by high-temperature solid state synthesis at 900°C in a platinum crucible from lithium carbonate, boric acid, and yttrium(III) oxide. The compound crystallizes monoclinically in the space group P 2 1 / c (no. 14) ( Z =4) isotypically to Li 3 Gd(BO 3 ) 2 . The structure was refined from single-crystal X-ray diffraction data: a =8.616(3), b =6.416(3), c =10.014(2) Å, β =116.6(2)°, V =494.9(3) Å 3 , R 1=0.0211, and wR 2=0.0378 for all data. The crystal structure of Li 3 Y(BO 3 ) 2 consists of [Y 2 O 14 ] dinuclear units, which are interconnected to each other by planar B(1)O 3 groups and LiO 4 tetrahedra via common edges and corners along the a axis.

Light-yellow microcrystalline samples of Cu[dca] ([dca] − ≡[N(CN) 2 ] − ≡dicyanamide anion) were obtained by blending an in-situ generated aqueous Cu + brine with stoichiometric amounts of Na[dca] dissolved in water. The crystal structure of Cu[dca] was solved and refined from powder X-ray diffraction (PXRD) data. Cu[dca] crystallizes in the orthorhombic space group Cmcm (no. 63) with the lattice parameters of a =356.28(3), b =611.10(9) and c =1525.87(10) pm. The crystal structure contains undulated chains of alternating Cu + and boomerang-shaped [N≡C–N–C≡N] − ions with C 2 v symmetry running along [100]. It is closely related to that of Ag[dca] crystallizing in space group Pnma (no. 62). The vibrational spectra for Cu[dca] and Cu[dca] 2 were recorded exhibiting modes typical for the dicyanamide anion. Comparative DSC/TG measurements were performed for both copper dicyanamides and the cyanide Cu[CN].

Gaseous diffusion of n -hexane into the reaction mixture of sodium dicyanamide NaN(CN) 2 with 15-crown-5 in tetrahydrofuran leads to a sodium dicyanamide compound [Na(15-crown-5)]N(CN) 2 ( 1 ). Compound 1 exhibits a centrosymmetric dumbbell-like structure constructed by dicyanamide ligands double-bridging [Na(15-crown-5)] + moieties with a μ-1,5 coordination mode. Solid-state photoluminescence experiments have shown that compound 1 emits violet luminescence, and its possible emission mechanism was investigated in detail based on theoretical calculations.