摘要:

We have examined to prepare a hybrid thin film consisting of bismuth triiodide and alkylammonium iodide by the conventional spin-coating technique. Their X-ray diffraction profiles and UV-Vis-NIR absorption spectra showed that the two-dimensional (Bi2I93−)xlayer was sandwiched between alkylammonium layers by the molecular fastener effect. The third order nonlinear property of the thin film was estimated by the third harmonic generation (THG) measurements. Strong THG signals were observed from the hybrid thin film with stearylammonium iodide, which gave 10−11esu order of χ(3)values.

ISSN:1058-725X    

DOI:10.1080/10587250008023505

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The microscopic magnetic local structure of layer-structured basic copper compounds Cu2(OD)3CH3(CH2)6COO was determined by the solid-state high-resolution deuterium NMR above 190 K. The magnetic interaction in a copper layer was probed by the isotropic NMR shifts of OD−ions and could be approximated by a sum of 1D-Heisenberg chains in the high temperature region. Four copper chains with different exchange interactionsJ= −209, −201, −122, and −44 K were found from the temperature dependence of the four distinct deuterium NMR signals. The derived values ofJalmost reproduced the high temperature behavior of the magnetic susceptibility χATvs.Tof this compound.

ISSN:1058-725X    

DOI:10.1080/10587250008023506

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The structure of conductive LB films based on dioctadecyldimethylammonium-Au(dmit)2(2C18-Au(dmit)2) is studied by introducing into a parameter, “waiting time”, which is defined as the time between the application of spreading solvent and the onset of compression. The π-A isotherms and the Brewster angle microscopy suggest that 2C18-Au(dmit)2complex forms multi-layered films on the water surface, whereas, the in-plane conductivity of the LB films after anodic oxidation increases with increasing the “waiting time”.

ISSN:1058-725X    

DOI:10.1080/10587250008023507

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

N-arylpyridinium molecules, 4, 6-bis(4,4′-bipyridine-1-y1)-pyrimidine (1) and 3,6-bis(4,4′-bipyridine-1-y1)-pyridazine (2) and 3-pyridylviologen (3) were designed and synthesized as photoelectrochemically active ligands for coordination polymer assemblies with various ions. Their two-step reduction processes involving ion-radicals generation were observed in both electrochemical and photochemical processes. The photochemical ionradical formation in1–3were observed in the solid state. The magnetic behavior of Cu complex of3after light irradiation showed the antiferromagnetic interaction between photochemically generated ionradical and Cu spins.

ISSN:1058-725X    

DOI:10.1080/10587250008023508

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A novel chiral organic radical 2-{4′-((S)-2″-methylbutoxy)phcnyl}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (1) and its metal complex, [1·Mn(II)(hfac)2]nwere synthesized and characterized. The radical1crystallizes in the orthorhombic space groupP212121(No. 19) witha= 11.494(3) Å,b= 25.328(3) Å,c= 6.1281(5) Å,V= 1748.0(4) Å3. The complex [1·Mn(II)(hfac)2]ncrystallizes in the same space group witha= 14.081(1) Å,b= 15.940(1) Å,c= 16.075(1) Å,V= 3608.1(4) Å3. X-ray crystal structure analysis of the complex revealed the formation of a helical-chain structure. The oxygen atoms of the radical1are ligated to two different manganese ions incisposition and exhibit the δ configuration in [1·Mn(II)(hfac)2]n. The magnetic measurements revealed that this chiral complex behaves as a ferrimagnet below TC= 4.5 K. It is characterized by a strong intrachain exchange correlation, the ratio between the intrachain and interchain exchange interactions being about 10−5.

ISSN:1058-725X    

DOI:10.1080/10587250008023509

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We apply muon spin relaxation (μSR) technique to study the magnetic behaviors of the photosensitive molecular magnet. 1:1 complexes of bis(hexafluoroacetylacetonate) manganese(II), {Mn(hfac)2} with diazodi(4-pyridyl)methane as a photoresponsible magnetic coupler. The μSR time spectra have been collected before and after laser irradiation as a function of temperature from 290 K to 10 K and as a function of irradiation time during 30 hours. While we are not successful in detecting meaningful effects of irradiation at the present stage, we discuss potential usability of μSR technique to reveal the expected unconventional feature of the photo- induced magnetic order.

ISSN:1058-725X    

DOI:10.1080/10587250008023510

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We applied the high-field technique to study the magnetization process in model substances. Measurements have been performed on the powder samples under a pulsed magnetic field up to 50 T. A family of organic verdazyl radical is a candidate of an isotropicS= 1/2 antiferro-magnetic linear chain model. The observed magnetization is practically zero up to a certain critical field around 40 T and steeply increases to the saturation value of 1 μB/molecule. The feature cannot be explained by the uniform chain model but agrees with the alternation linear chain model closed to the dimer model in which the ground state is a nonmagnetic singlet with an energy gap between the excited triplet state. Metal-assembled tetranuclear complexes [Mn(MeOH)L(OH)M(bpy)]2represent a prototype of geometrically frustrated spin systems. We observed a step-like magnetization process which clearly shows the successive transitions among quantum states with different total spins.

ISSN:1058-725X    

DOI:10.1080/10587250008023511

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Recently, Iwamura's group has succeeded in synthesizing the interesting new tetranuclear cluster composed of two paramagnetic Mn2+ions (S=5/2 per ion) and two organic free radicals (S=1/2 per radical) as bridging ligand, [{Mn(hfac)2}2(bnn)] (bnn=2,2′-bis[(1-oxyl-3-oxide-4,4,5,5-tetramethyl-imidazolinyl)]). The crystal structure is trielinic (space groupP1) and each cluster is composed of two triangles which share their own base like a “butterfly”. There are two kind of exchange pathways within the cluster and both of them are likely to be antiferromagnetic. Therefore, spin frustration may occur and we expect many possible ground states with different total spins (ST=0 toST=6), depending on the relevant interactions and magnetic field.

ISSN:1058-725X    

DOI:10.1080/10587250008023512

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Magnetic properties of nickel(II) complexes containing di(2-pyridyl)amine anion (dpa−) or cyanamide anion (ca−) are investigated. Ni/dpa complexes prepared from NiCl2and Ni(NO3)2showed magnetic transition at 17 and 19 K, respectively. The Ni/ca complex prepared from NiCl2showed magnetic transition at 25 K.

ISSN:1058-725X    

DOI:10.1080/10587250008023513

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Magnetic phase transitions of PM2·CoCl2, PM2·CoBr2, and PM2·FeCl2(PM = pyrimidine) were observed atTN= 4.4, 4.7, and 6.1 K, respectively, as defined by the peak of χac′. They are characterized to be isomorphous, belonging to the space groupI4122, and canted antifer-romagnets belowTN. The neutron diffraction study supports the principally antiferromagnetic structure.

ISSN:1058-725X    

DOI:10.1080/10587250008023514

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor