Akihiko Tsuge

Preparation and Characterization of 7,16-Dibenzoylated Tetraaza[14]Annulene Copper(II) Complexes

Abstract The reaction between a tetraaza[14]annulene copper(II) complex and a series of p-substituted benzoyl chlorides gave the corresponding 7,16-dibenzoylated complexes in satisfactory yields. The mass spectra reveal the presence of molecular ion peaks based on the 7,16-dibenzoylated complexes. A strong IR band which is associated with a C=O stretching mode is newly observed in the 1653–1660 cm−1 region upon benzoylation. The electronic spectra for the complexes scarcely change on benzoylation and are similar to those for square-planar complexes. The spin Hamiltonian parameters for the benzoylated copper(II) complexes are analogous to those for the copper(II) complex that is not benzoylated. These copper(II) complexes are approximately square-planar with an unpaired electron in the dx 2-y 2 orbital. Referee I: H. Kula Referee II: K. Kasuga

Preparation and spectral properties of nickel(II) and copper(II) complexes with two isomeric cyclohexylcyclams

Abstract The nickel(II) complexes of two isomeric cyclohexylcyclams were prepared by employing a nickel template reaction. The cyclohexylcyclams were synthesized from the nickel(II) complexes and then the copper(II) complexes were prepared from the free ligands and copper(II) perchlorate. The nickel(II) and copper(II) complexes exhibit clusters of ions corresponding to [M ue5f8 ClO4]+ and [M ue5f8 2ClO4+2H]+ which is the base peak in FAB mass spectra. A strong band observed at ca 3200 cm−1 is assigned to the Nue5f8H stretching mode and the band is slightly shifted to lower frequency on metal coordination, indicating freshly strong bands due to ClO4− stretching mode at ca 1090 and ca 620 cm−1. The molar conductances for the complexes are 1 : 2 electrolytes in N,N-dimethylformamide and the perchlorate anions are ionized on dissolution in the solvent. The nickel(II) and copper(II) complexes of the two isomers are subjected to the square-planar ligand-field, but the ligand-field band for the nickel(II) complex of isomer Lt3, trans-cyclohexylcyclam, shows the distorted octahedral form in coordinating solvent. ESR spectra for the copper(II)_ complexes of the two isomers also give the spin Hamiltonian parameters of the square-planar coordination. 13C-NMR spectral results are comparable with those of another spectra.

Characterization, Spectroscopic Properties and Crystal Structure of a Tetraaza[14]Annulene Manganese(III) Complex

Abstract The manganese(III) complex of tmtaa, (H2tmtaa = 7, 16-dihydro-6, 8, 15, 17-tetramethyldibenzo[b, i][1, 4, 8, 11]tetraazacyclotetradecinc). was prepared by a ligand exchange reaction and characterized by mass, infrared and electronic spectra as well as DSC measurement. The crystal structure has been determined by X-ray single crystal diffraclion. There are two crystallographically independent molecules of Mn(tmtaa)NCS in the asymmetric unit and one independent solvent molecule (acetonitrilc). The coordination around the manganese(III) is essentially a five-coordinate square pyramidal configuration with one nitrogen atom of an anionic NCS and four nitrogen atoms of a dianionic tmtaa. The average bond distances of Mn-N for tmtaa are 1969(6) and 1.961(3) A, respectively. while the distances of the manganese to the nitrogen of NCS are 2.094(8) and 2.086(8) A, respectively. The manganese(III) is displaced by 0.402 and 0.388 A, respectively, from the N4 donor plane.

PREPARATION AND SPECTROSCOPIC PROPERTIES OF FIVE 7,16-BIS(AZOPHENYL)TETRAAZA 14 ANNULENE NICKEL(II) COMPLEXES

Abstract The diazo coupling reaction of a tetraazal [14]annulene nickel(II) complex (1) with series of para-substituted phenyldiazonium tetrafluoroborates led to the corresponding 7,16-bis(azophenyl) products. The nickel (II) complexes formed are approximate square-planar coodinations and diamagnetic. The olefinic proton signals at the 7,16-positions of the nickel(II) complexes are destroyed by the diazo coupling reaction in the NMR spectra. The carbon signals at the 7,16-positions exhibit downfield shifts of about 30 ppm with the diazo coupling reaction.

SYNTHESIS AND STRUCTURE OF NOVEL 1,8-BRIDGED FLUORENOPHANES

A novel 1,8-bridged fluorenophane (4a) is found to nassume an

Synthesis and electrochemical properties of bis([2.2]metacyclophane) bipyridinium

lsquoinward-folded’ conformation with the bulky ntert-butyl group located in the cavity, a situation nwhich is different from the conformation of the corresponding ndithiafluorenophane (3a).

Evaluation of Transannular Interaction of [2.3]Metacyclophane-diazonium Tetrafluoroborate and its Dediazoniated Derivatives

Bis([2.2]metacyclophane) bipyridinium was synthesized for the first time and it was found that this cyclophane compound was reduced at more negative potentials than the corresponding bipyridinium, having no cyclophane skeleton, due to a transannular CH–p interaction between the aromatic ring of the cyclophane and CH portion next to nitrogen atom.

DIENE-TRANSMISSIVE HETERO DIELS-ALDER REACTION OF 1,5-DIPHENYL-1,4-PENTADIEN-3-ONE

Transannular interactions of [2,3]metacyclophane-diazonium tetrafluoroborate and its dediazoniated derivatives have been evaluated by 1H NMR, IR, UV and stability constant determination.