Molecular design of nonlinear optical polymer based on DCM to enhance the NLO efficiency and thermal stability

Crystal structures of [Cu(phen)(H2O)3(MF6)]·H2O (M = Ti, Zr, Hf) and [Cu(phen)(H2O)2F]2[HfF6]·H2O

The crystal structures of three bridged bimetallic mol-ecular compounds, namely, tri-aqua-2κ3 O-μ-fluorido-penta-fluorido-1κ5 F-(1,10-phenanthroline-2κ2 N,N')copper(II)titanium(IV) monohydrate, [Cu(TiF6)(phen)(H2O)3]·H2O (phen is 1,10-phenanthroline, C12H8N2), (I), tri-aqua-2κ3 O-μ-fluorido-penta-fluorido-1κ5 F-(1,10-phenanthroline-2κ2 N,N')copper(II)zirconium(IV) monohydrate, [Cu(ZrF6)(phen)(H2O)3]·H2O, (II), and tri-aqua-2κ3 O-μ-fluorido-penta-fluorido-1κ5 F-(1,10-phenanthroline-2κ2 N,N')copper(II)hafnium(IV) monohydrate, [Cu(HfF6)(phen)(H2O)3]·H2O, (III), and one mol-ecular salt, bis-[diaqua-fluorido-(1,10-phenanthroline-κ2 N,N')copper(II)] hexa-fluorido-hafnate(IV) dihydrate, [CuF(phen)(H2O)2]2[HfF6]·2H2O, (IV), are reported. The bridged bimetallic compounds adopt Λ-shaped configurations, with the octa-hedrally coordinated copper(II) center linked to the fluorinated early transition metal via a fluoride linkage. The extended structures of these Λ-shaped compounds are organized through both intra- and inter-molecular hydrogen bonds and inter-molecular π-π stacking. The salt compound [Cu(phen)(H2O)2F]2[HfF6]·H2O displays an isolated square-pyramidal Cu(phen)(H2O)2F+ complex linked to other cationic complexes and isolated HfF6 2- anions through inter-molecular hydrogen-bonding inter-actions.

The effects of bromine atoms on the photophysical and photochemical properties of 3-cinnamoylcoumarin derivatives

Coumarin derivatives modified using bromine atoms linked onto the right benzene ring (mainly in the HOMO) could enhance singlet oxygen generation capability.

The role of polar, lamdba (Λ)-shaped building units in noncentrosymmetric inorganic structures

A methodology for the design of polar, inorganic structures is demonstrated here with the packing of lambda (Λ)-shaped basic building units (BBUs). Noncentrosymmetric (NCS) solids with interesting physical properties can be created with BBUs that lack an inversion center and are likely to pack into a polar configuration; previous methods to construct these solids have used NCS octahedra as BBUs. Using this methodology to synthesize NCS solids, one must increase the coordination of the NCS octahedra with maintenance of the noncentrosymmetry of the bulk. The first step in this progression from an NCS octahedron to an inorganic NCS solid is the formation of a bimetallic BBU. This step is exemplified with the compound CuVOF(4)(H(2)O)(7): this compound, presented here, crystallizes in an NCS structure with ordered, isolated [Cu(H(2)O)(5)](2+) cations and [VOF(4)(H(2)O)](2-) anions into Λ-shaped, bimetallic BBUs to form CuVOF(4)(H(2)O)(6)·H(2)O, owing to the Jahn-Teller distortion of Cu(2+). Conversely, the centrosymmetric heterotypes with the same formula MVOF(4)(H(2)O)(7) (M(II) = Co, Ni, and Zn) exhibit ordered, isolated [VOF(4)(H(2)O)](2-) and [M(H(2)O)(6)](2+) ionic species in a hydrogen bond network. CuVOF(4)(H(2)O)(7) exhibits a net polar moment while the heterotypes do not; this demonstrates that Λ-shaped BBUs give a greater probability for and, in this case, lead to NCS structures.

Linear and V-shaped nonlinear optical chromophores with multiple 4H-pyran-4-ylidene moieties

A simple synthesis of dipolar one- and two-dimensional chromophores bearing two or three 4H-pyran-4-ylidene moieties is reported. Whereas the pyranylidene fragments acting as donors are proaromatic, the spacer one is not. In the linear derivatives, chain elongation gives rise to a sharp increase in the second order nonlinear optical responses, but some V-shaped derivatives display first hyperpolarizabilities (beta) lower than those of their linear analogues. This uncommon feature lends experimental support to previous theoretical studies on the relative contribution and sign of the beta-tensor components.