Family Of Bis Research Articles

Zirconium(IV) Sandwich Complexes of Porphyrins and Tetraazaporphyrins: Synthesis, Structure, and Nonlinear Optical Properties

A family of bis(porphyrin) zirconium sandwich complexes containing octaethylporphyrin (OEP) and octaethyltetraazaporphyrin (OETAP) was synthesized and characterized by UV−vis and NMR spectroscopies. The two ligands are structural analogues yet have dramatically different redox properties (the redox potentials of OETAP complexes are much more positive than those of the corresponding OEP complexes). Cyclic voltammetry results indicate that Zr(OETAP)2 is about 600 mV harder to oxidize and about 600 mV easier to reduce than Zr(OEP)2, while the mixed sandwich Zr(OEP)(OETAP) exhibits intermediate redox potentials. The structures of Zr(OEP)(OETAP) and Zr(OETAP)2 were determined by X-ray crystallography and compared to Zr(OEP)2. The solid-state structures were very similar, indicating that OEP and OETAP have similar steric parameters and that observed spectroscopic and electrochemical differences are due primarily to electronic factors. The one electron oxidized porphyrin sandwiches were also synthesized. Characterization by UV−vis, near-IR, EPR, and IR spectroscopies confirm the π radical nature of these complexes. IR spectra indicate that the cation is delocalized over the entire complex in both [Zr(OEP)(OETAP)]+[SbCl6]- and [Zr(OETAP)2]+[SbCl6]-, consistent with a strongly coupled π system. Additional evidence for strong coupling was obtained from measurement of the nonlinear optical properties of the mixed complex; the molecular hyperpolarizability is negative, indicating that the dipole moment reverses direction upon electronic excitation.

ChemInform Abstract: Photophysics of 10‐Substituted Bis(2‐(9‐anthryl)ethyl) Glutarates.

Photophysical interactions between pendant anthryl groups in a family of bis(2-(9-anthryl)ethyl) glutarates have been characterized by steady-state and time-resolved fluorescence measurements. As the size of the 10-substituent increases, the rate of excimer formation decreases and the monomer-excimer equilibrium shifts toward the monomer. Thermodynamic and kinetic parameters influencing excimer formation are described.

Photophysics of 10-substituted bis[2-(9-anthryl)ethyl] glutarates

Photophysical interactions between pendant anthryl groups in a family of bis(2-(9-anthryl)ethyl) glutarates have been characterized by steady-state and time-resolved fluorescence measurements. As the size of the 10-substituent increases, the rate of excimer formation decreases and the monomer-excimer equilibrium shifts toward the monomer. Thermodynamic and kinetic parameters influencing excimer formation are described.

Steric effects of polymethylene chain length on the liquid-liquid extraction of copper(II) with bis(4-acylpyrazol-5-one) derivatives

A novel family of bis(4-acylpyrazol-5-one) derivatives in which two 1-phenyl-3-methyl-4-acylpyrazol-5-one subunits are linked by a polymethylene chain −(CH 2 ) n - of various lengths (n=0-8, 10, 20) has been designed. The distribution curves show that each bis(4-acylpyrazol-5-one) derivative is a diprotic acid, H 2 BPn

Transition metal coordination compounds with the dithiooxalate ligand. Synthesis, spectroscopic studies, crystal structure, and bonding of (C5H5NH)2[Ni(S2C2O2)2

Several new compounds belonging to the family of bis(dithiooxalato)-nickelate(II) complex anion with the general formula (BH)2[Ni(S2C2O2)2], where B=pyridine, 3-methylpyridine, 3-ethylpyridine, 4-methylpyridine, and 4-ethylpyridine (hereafter abbreviated as PYNIDT, M3NIDT, E3NIDT, M4NIDT, and E4NIDT, respectively) have been prepared. PYNIDT, M3NIDT, and E3NIDT are isostructural between them and different from the two other compounds, M4NIDT and E4NIDT, which are also isostructural. All of these compounds crystallize in the monoclinic system, space groupP21/n withZ=2. Crystal parameters for PYNIDT are:a=5.793(3),b=14.280(5),c=11.222(3) A,β=97.29(4)°,V=920.8(9) A3,F(000)=468,D x =1.66,D o=1.65(1) Mg m−3,R=0.048, andR w =0.057 for 1236 observed reflections. The IR and UV-V spectra show that the organic bases are protonated and the anion presents the well-known spectrum for the bis(dithiooxalato)-nickelate(II) anions. Thermogravimetric studies indicate that the compounds are anhydrous. The structure solution of PYNIDT confirms that this compound contains discrete quasi-planar complex [Ni(S2C2O2)2]2− anions and (C5H5NH)+ planar cations linked through hydrogen bonds. The structure stacks into layers where the ions are associated into cation⋯anion⋯cation entities through bifurcated hydrogen bonds.

ChemInform Abstract: Dinickel and Dicopper Complexes with N,N‐Linked Bis(cyclam) Ligands. An Ideal System for the Investigation of Electrostatic Effects on the Redox Behavior of Pairs of Metal Ions.

AbstractA novel family of bis(macrocycles) (Ib), (Id) is prepared starting with (II) which is obtained from cyclam.