The role of neutral and ionized oxygen defects in the emission of tin oxide nanocrystals for near white light application.

Tin oxide (SnO2) nanocrystals (NCs) based phosphor was synthesized by a green chemistry microwave-assisted hydrothermal method at different reactor pressures. The x-ray diffraction analysis showed that a single rutile SnO2 phase with a tetragonal lattice structure was formed. The photoluminescence emission was measured for He-Cd laser excitation at 325 nm and it showed a broad band emission from 400 to 800 nm for all the synthesized reactor pressures. The broad emission spectra were due to the creation of various oxygen and tin defects as confirmed by x-ray photoelectron spectroscopy data. The origin of the emission in the SnO2 NCs is discussed with the help of an energy band diagram. Analysis suggests that the visible emission of SnO2 NCs is due to a transition of an electron from a level close to the conduction band edge to a deeply trapped hole in the SnO2 NCs. The NCs were found to be suitable for warm near white light emission device applications.

µ-(2,2'-Bipyrimidine)-bis-[dichlorido-palladium(II)] dimethyl-formamide monosolvate.

In the title compound, [Pd(2)Cl(4)(C(8)H(6)N(4))]·C(3)H(7)NO, the two Pd(2+) cations have a distorted square-planar coordination sphere and are bridged by a bis-bidentate 2,2'-bipyrimidine ligand. Two terminal chloride anions are also bonded to each of the Pd(2+) cations. The dinuclear complex and the dimethylformamide solvate molecule lie on the inter-section of a twofold rotation axis and a mirror plane, with disorder present in the solvate mol-ecule. There is a slight distortion from the square-planar metal geometry, as indicated by the bite angles of 81.77 (13)° and 91.63 (5)°. The C and O atoms of the solvent mol-ecule are disordered over two sets of sites of equal occupancy.

5-(3,4-Dimeth-oxy-benzyl-idene)-1,3-dimethyl-1,3-diazinane-2,4,6-trione.

In the title compound, C(15)H(16)N(2)O(5), the dihedral angle between 1,3-diazinane and benzene rings is only 4.27 (1)°. The essentially planar mol-ecular structure is characterized by a short intra-molecular C-H⋯O separation and by an exceptionally large bond angle of 138.25 (14)° at the bridging methine C atom. The meth-oxy groups deviate somewhat from the plane of the benzene ring, with C-C-O-C torsion angles of -15.6 (1) and 9.17 (6)°. In the crystal, mol-ecules form centrosymmetric dimers via donor-acceptor π-π inter-actions, with a centroid-centroid distance of 3.401 (1) Å.

4-(2-Bromo-phen-yl)-2-phenyl-pyrano[3,2-c]chromen-5(4H)-one.

In the title compound, C24H15BrO3, the pyran-ochromenone ring is essentially planar, while the 2-bromo-phenyl group is almost perpendicular to it [85.58 (6)°]. In the crystal, inversion dimers linked by pairs of weak C-H⋯π bonds occur; there is also a short inter-atomic contact found between the Br and carbonyl O atoms [3.016 (1) Å].

2,5-Dihexyl-thio-phene 1,1-dioxide.

In the title mol-ecule, C16H28O2S, the two n-hexyl groups are in all-trans conformations. Their C atoms are situated close to the plane of the thio-phene ring with a maximum deviation of 0.718 (6) Šfor one of the terminal methyl groups. In the crystal, a short C-H⋯O contact is observed between thio-phene 1,1-dioxide groups.

1-(3-Benzyl-4,6-dibenz-yloxy-2-hy-droxy-phen-yl)ethanone.

The title compound, C(29)H(26)O(4), is essentially planar in the acetophenone portion that includes both the hy-droxy and a benz-yloxy O atoms, with an r.m.s. deviation of 0.0311 Å. The other two substituents inter-sect the plane at 70.45 (3) and 59.55 (4)°. In the molecule there is an intramolecular O-H⋯O hydrogen bond. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, as well as C-H⋯π and π-stacking inter-actions, with centroid-centroid distances 3.6570 (2) Å.

4,5-Bis(2,4-di-tert-butyl-phen-oxy)phthalonitrile.

In the title compound, C(36)H(44)N(2)O(2), the dihedral angles between the phthalonitrile ring and the two di-tert-butyl-benzene rings are 68.134 (8) and 70.637 (11)°. The two nitrile groups are almost coplanar with the phthalonitrile ring except for one of the N atoms which deviates from the plane by 0.125 (4) Å. One of the tert-butyl groups is disordered over two orientations, with refined occupancies of 0.814 (6) and 0.186 (6). Intra-molecular C-H⋯O inter-actions stabilize the molecular structure. The crystal packing is stabilized by inter-molecular C-H⋯N inter-actions.

Dimethyl 2,6-dimethyl-4-phenyl-pyridine-3,5-dicarboxyl-ate.

In the title compound, C(17)H(17)NO(4), the dihedral angle between the benzene and pyridine rings is 75.51 (4)°. The benzene and pyridine rings are both approximately planar (r.m.s. deviations of 0.0040 and 0.0083 Å, respectively), indicating that the pyridine N atom is not protonated. The crystal structure is stabilized by weak inter-molecular C-H⋯O and C-H⋯N inter-actions.

Racemic tricarbon-yl[7-meth-oxy-2-(η-phen-yl)chromane]-chromium(0).

In the title compound, [Cr(C(16)H(16)O(2))(CO)(3)], the Cr(0) atom of the Cr(CO)(3) unit is coordinated to the phenyl ring of the flavan ligand in an η(6) mode, with a normal arene-to-metal distance. The Cr(CO)(3) unit exhibits a three-legged piano-stool conformation, while the dihydro-pyran ring displays a distorted envelope configuration. The phenyl ring is twisted away from the fused ring system by 25.5 (2)°. The meth-oxy group is almost coplanar with the phenyl ring [C(Me)-O-C(ar)-C(ar) torsion angle = 8.46 (2)°]. The crystal packing is stabilized by inter-molecular C-H⋯O inter-actions.

NMR data of a Grubbs 2nd generation catalyst p-cresolate derivative.

The data presented in this article is related to the research article entitled "Spectroscopic characterisation of Grubbs 2nd generation catalyst and its p-cresol derivatives" (Swart et al. 2021). The 1D and 2D NMR characterisation data of the p-cresol derivative of the Grubbs 2nd generation catalyst, where one of the chloride ligands is replaced by the p-cresolate to form a Ru-O coordination compound (3) is reported. The characterization data include information obtained from 1H, 13C, Heteronuclear Single Quantum Coherence (HSQC), Heteronuclear Multiple Bond Correlation (HMBC), Homonuclear Correlation Spectroscopy (COSY), Nuclear Overhauser Effect (NOE) and Distortionless Enhancement by Polarization Transfer (DEPT) NMR spectroscopy.

2',3,4,4'-Tetra-meth-oxy-chalcone.

IN THE TITLE COMPOUND [SYSTEMATIC NAME: 1-(2,4-dimethoxyphenyl)-3-(3,4-dimethoxyphenyl)prop-2-en-1-one], C(19)H(20)O(5), the dihedral angle between the benzene rings is 26.88 (5)°. One of the meth-oxy groups is twisted slightly away from the plane [C-O-C-C torsion angle = -12.8 (3)°] while the others are almost co-planer [C-O-C-C torsion angles = -3.2 (3), 2.6 (3) and -3.6 (3)°]. The crystal packing is stabilized by inter-molecular C-H⋯O inter-actions. A weak intra-molecular C-H⋯O inter-action occurs.

Racemic tricarbon-yl(η-7-meth-oxy-flavan)chromium(0).

IN THE TITLE COMPOUND [SYSTEMATIC NAME: tricarbonyl(η(6)-7-methoxy-2-phenyl-3,4-dihydro-2H-1-benzopyran)chromium(0)], [Cr(C(16)H(16)O(2))(CO)(3)], the Cr(CO)(3) unit is coordinated by the phenyl-ene ring of the flavan ligand, exhibiting a three-legged piano-stool conformation, with a point to plane distance of 1.750 (1) Å. The phenyl ring is twisted away from the fused ring system by 36.49 (5)° (r.m.s. deviation = 0.027 Å; fitted atoms are the C(6) ring and the attached fused-ring C and O atoms). The dihydro-pyran ring displays a distorted envelope configuration by displacement of the phenyl-bearing and the adjacent ring C atoms from the fused-ring system plane by 0.356 (2) and 0.402 (2) Å, respectively.

Racemic tricarbonyl[(4a,5,6,7,8,8a-η)-2-phenyl-3,4-dihydro-2H-1-benzopyran]chromium(0).

The title compound, [Cr(C(15)H(14)O)(CO)(3)], displays a distorted envelope configuration of the dihydro-pyrane ring. The dihedral angle between the phenyl and phenyl-ene rings is 50.63 (4)°. The Cr(0) atom is coordinated by three CO groups and the phenyl-ene ring of the flavan ligand in an η(6) mode, with a common arene-to-metal distance.

2',3,4,4',5-Penta-meth-oxy-chalcone.

In the title chalcone [systemetic name 1-(2,4-dimeth-oxy-phen-yl)-3-(3,4,5-trimeth-oxy-phen-yl)prop-2-en-1-one], C(20)H(22)O(6), the dihedral angle between the plane of the two benzene rings is 7.03 (4)° with all but one of the meth-oxy groups essentially co-planar with these rings [C-C-O-C torsion angles = -76.1 (2), -0.7 (3), 1.8 (3), -6.2 (3), 2.0 (3)°]. An intra-molecular C-H⋯O inter-action occurs. The crystal packing is stabilized by weak inter-molecular C-H⋯O hydrogen bonds.

Tricarbon-yl(η-4',7-dimethoxy-iso-flavone)chromium(0).

The metal atom of the Cr(CO)(3) unit of the title compound, [Cr(C(17)H(14)O(4))(CO)(3)], is coordinated to the methoxy-phenyl ring of the isoflavone ligand; the Cr(CO)(3) unit exhibits a three-legged piano-stool conformation. The aromatic ring of the methoxy-phenyl group is twisted by 42.49 (9)° with respect to the γ-pyrone ring. In the fused-ring, the dihedral angle between the phenyl-ene and γ-pyrone rings is 3.08 (13)°.

Tricarbon-yl(η-flavone)chromium(0).

In the title compound, [Cr(C(15)H(10)O(2))(CO)(3)], the Cr(CO)(3) unit exhibits a three-legged piano-stool conformation. The chromium metal centre is coordinated by the phenyl ring of the flavone ligand [Cr-(phenyl centroid) distance = 1.709 (1) Å]. The ligand is approximately planar, the dihedral angles between the γ-pyrone ring and the phenyl ring and between the γ-pyrone and the phenyl-ene ring being 2.91 (5) and 3.90 (5)°, respectively. The mol-ecular packing shows π-π stacking between the flavone ligands of neighbouring mol-ecules.

Tetra-kis(µ-2-methyl-benzoato)bis-[(2-methyl-benzoic acid)copper(II)].

In the title centrosymmetric dinuclear compound, [Cu(2)(C(8)H(7)O(2))(4)(C(8)H(8)O(2))(2)], four o-toluate anions form a cage around two Cu atoms in a syn-syn configuration. Two more o-toluic acid mol-ecules are apically bonded to the Cu atoms, which show a square-pyramidal coordination geometry. The acid H atoms are hydrogen bonded to the cage carboxyl O atoms [O⋯O = 2.660 (2) Å]. The mol-ecular packing forms a puckered pseudo-hexa-gonal close-packed layer in the (h00) plane, with soft inter-molecular H⋯H contacts (2.46-2.58 Å).

Tetra-kis(µ-4-ethyl-benzoato-κO:O')-bis-[(4-ethyl-benzoic acid-κO)copper(II)].

The molecule of the title compound, [Cu(2)(C(9)H(9)O(2))(4)(C(9)H(10)O(2))(2)], lies on a center of inversion. It consists of four bridging ethyl-benzoate ligands, forming a cage around two Cu atoms in a syn-syn configuration, and two monodentate ethyl-benzoic acid ligands bonded apically to the square-planar Cu atoms. The Cu⋯Cu distance is 2.6047 (5) Å.