摘要:

Reaction of [Cp*RhCl2]2(1) with (LiNH)2C10H6-2,3 gives the mononuclear species Cp*Rh(NH)2C10H6-2,3 (3), which is selectively converted to the amido-bridged dinuclear Rh(III) complex [Cp*Rh{μ2-(NH)2C10H6-2,3}(μ2-Cl)RhCp*]PF6(4; Cp* = η5-C5Me5) upon treatment with1/AgPF6in acetone. The molecular structure of4has been determined by X-ray crystallography.

ISSN:1058-725X    

DOI:10.1080/10587250008038237

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The ability of cyclic planar [RR'C2B3H2X]4−carborane ligands (R, R′ = alkyl, aryl, SiMe3, H; X = alkyl, Cl, Br, I, H) to bind tightly to transition and main-group metals on both sides of the C2B3 ring plane allows the construction of a wide range of polymetallic multidecker sandwich complexes involving different metals, metal oxidation states, and molecular architectures. Although these ligands are isoelectronic and isosteric analogues of C5H5−, they form stronger covalent bonds to metal centers, and can stabilize many robust, isoluhle structural types that are not readily accessible (or are completely unknown) in metallocene chemistry. Many of these metallacarborane sandwich complexes are paramagnetic and exhibit extensive electron-delocalization that can be “tuned” by redox action or by the introduction of appropriate substituents to the carborane ligands or the metal centers. This remarkable versatility suggests that there is considerable potential for the creation of novel polymeric and solid state materials that can be tailored to have desired electronic, optical, or other properties. This review summarizes recent efforts in the designed syntheses of oligomeric and polymeric systems and the systematic exploration of structure-property relationships.

ISSN:1058-725X    

DOI:10.1080/10587250008038238

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The metal substituent effect on complementary triple hydrogen bonding pairs was investigated by1H NMR spectroscopy. The results demonstrated that the metal ion reduced the hydrogen bonding ability of the ADA complex [NBu4][Rh(cod)(orotate)] with 2,6-diaminopyridine.

ISSN:1058-725X    

DOI:10.1080/10587250008038239

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Syntheses of molecular necklaces and open framework materials using coordiantion bonds are described. In the synthesis of molecular necklaces, the barrel-shape molecule cucurbituril is used as a molecular “bead” and metal ions or metal complexes are used as “glue” or “angle connectors”. Two different approaches were taken. In one approach, linear pseudorotaxanes react with Pt(en)(NO3)2(en = ethylenediamine) to produce [4]MNs and [5]MNs. In the other approach, a′ 2 + 2′ approach, preorganized, L-shaped pseudorotaxanes containing two molecular “beads” react with a metal ion (or a metal complex withcisvacant coordination sites) to form [5]MNs. Rubidium and cucurbituril form a one-dimensional coordination polymer in the solid state, in which cucurbituril molecules stack atop one another through coordination of their carbonyl groups to the rubidium ions in between. The coordination polymer chains are arranged in such a way as to produce a honeycomb structure with large linear hexagonal channels parallel to the polymer chains.

ISSN:1058-725X    

DOI:10.1080/10587250008038240

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Mononuclear and trinuclear nickel(II) and copper(II) complexes containing the N3O3-type ligand (H3L), obtained by condensation of 1,1,1-tris(aminomethyl)ethane and salicylaldehyde (1 : 3), were synthesized. Two mononuclear nickel(II) complex units ([Ni(HL)]) are aggregated due to hydrogen bonding between the phenol group of one unit and the phenolate group of the other to give a dimer with homochirality. The trinuclear nickel(II) complex. [Ni3L2] consists of three face-sharing octahedra. Three nickel(II) ions form a linear array. Two terminal nickel(II) ions are coordinated octahedrally by L. The central and two terminal nickel(II) ions are bridged by six phenolate oxygen atoms. In the mononuclear square-planar copper(II) complex, [Cu(HL)], one arm of the tripodal ligand is not coordinated to the metal. On the basis of the absorption spectra of the copper(II) complexes, the coordination geometry around each copper ion of the trinuclear complex is assigned to be square planar and copper ions will be bridged by L.

ISSN:1058-725X    

DOI:10.1080/10587250008038241

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The reaction offac(S)-[RhIII(aet)3] (aet = 2-aminoethanethiolate) with [AuIIICl4]−in water gave an S-bridged pentanuclear complex [AuI3{RhIII-(aet)3}2]3+(1), accompanied by the spontaneous reduction of AuIIIto AuI. The crystal structure of1(NO3)3·4H2O was determined by X-ray crystallography. In1two octahedralfac(S)-[Rh(aet)3] units are linked by three linear AuIatoms to form a trigonal-bipyramid-type RhIII2AuI3pentanuclear structure with an averaged AuI-AuIdistance of 3.083(5) Å. The two RhIII2AuI3cations contact with each other through one AuI-AuIinteraction with a distance of 3.311(3) Å. The optically active δδ-1was derived from ΔΔΔΔ-[Zn3(OH){Rh(aet)3}4]5+by reacting with [AuCl4]−in water.

ISSN:1058-725X    

DOI:10.1080/10587250008038242

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In order to construct artificial functional mimics of photosynthetic antenna complexes, two N-methylimidazole substituents were introduced at the facing meso positions of porphyrin and metalated by Mg2+ion. In contrast to the specific dimer formation of pentacoordinating Zn atom, Mg metal center accepted the 6th ligation by imidazole and extended the slipped cofacial coordination to higher organized structures. FT Ion spray mass spectrum detected porphyrin oligomers up to a pentamer when the sample was prepared from a MeOH solution, and a heptamer from a CHCl3-MeOH (1/1) solution. When imidazole instead of N-methylimidazole was employed as the porphyrin substituent, Zn2+dimer, they further connected each other by hydrogen bonds to extend the supramolecular structure with a characteristic splitting and significant broadening of the Soret band.

ISSN:1058-725X    

DOI:10.1080/10587250008038243

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

NaH promoted deprotonation of the NH groups in poly(benzimidazole)s, [-Im-C6H4-]n(1a) (Im: 5,5′-dibenzimidazole-2,2′-diyl) and [{-Im-(CH2)11O(CH2)11-}0.98{-Im-(CH2)10}0.02-]n(1b) followed by addition of 4 equiv. of EuCl3gave new soluble Eu complexes of poly(benz-imidazole)s (2aand2b) having N-Eu bonds in 66 and 42% yields, respectively. The Eu polymer complexes2aand2bhave two molecules of Cl and DMSO as ligands, which was revealed from IR and1H NMR spectra and elemental analysis. Energy transfer from the benzimidazole group in polymer main chain to the Eu(III) metal was occurred upon irradiation with UV light in the solid state. This resulted in light emission from both the polymer chain and the Eu(III) center, although the Eu(III) itself could not be excitated by irradiation with the UV light.

ISSN:1058-725X    

DOI:10.1080/10587250008038244

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Tetranuclear complexes [CuL2H]4(1), [CuL2Me]4(2), and [CuL2Cl]4(3) with a reduced Schiff base type tridentate ligand H2L2H and its homologous with a substituent on the 2-hydroxymethylphenyl moiety (4-Me, H2L2Me; 4-Cl, H2L2Cl) were prepared and characterized by elemental analyses and magnetic measurements. The crystal structure of1was determined by X-ray crystallography. Tetracopper core is represented as a dimer-of-dimers structure by the stacking of two dicopper units bridged by alcoholic oxygens. One of the dicopper units contains square pyramidal (SP) Cu(II) ions, whereas the geometry of each Cu(II) ion in the other unit is described as essentially distorted trigonal bipyramid (TBP). Magnetic behaviors of the complexes are explained by modified equation based on the theoretical Spin Hamiltonian. The exchange integrals (-2J) are evaluated at 292–366 cm−1for SP dicopper cores and 104–120 cm−1for TBP, respectively, indicating the existence of different type of antiferromagnetic interaction-pathways corresponded to each copper geometry.

ISSN:1058-725X    

DOI:10.1080/10587250008038245

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A unique triple hydrogen-bonding system has been constructed between the transition metal (Ni(II), Cu(II), Co(III)) complexes with bis(biphenylbiguanidato) andortho-phenylenebis(biuretato) ligands, which have been characterized by IR and1H-NMR spectroscopies and thermogravimetric and X-ray structure analyses.

ISSN:1058-725X    

DOI:10.1080/10587250008038246

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor