Yoichi Habata

Molecular structure and electrochemical properties of the PtII complex of 1,1′-bis(methylthio)ferrocene and the PdII complexes of 1,4,7-trithia[7]- and 1,5,9-trithia[9] (1,1′)ferrocenophanes

Abstract Molecular structures of (triphenylphosphine) [1,1′-bis-(methylthio)ferrocene-S,S′,Fe]Pt(BF4)2 (1), (1,5,9-trithia[9]ferrocenophane-S,S′,S″,Fe)Pd(BF4)2 (2), and (acetonitrile)(1,4,7-trithia[7]ferrocenophane-S,S′,S″,Fe)Pd(BF4)2 (3) were determined by X-ray analyses. The Pt in 1 and the Pd atom in 2 have a somewhat distorted square-planar geometry including the Fe atom of the ferrocene moiety, while the Pd atom in 3 is coordinated by one equivalent of acetonitrile and takes a distorted tetragonal-pyramidal geometry. The distances of the FeM bond (M = Pd, Pt) in 1–3 are 2.851(2), 2.827(2), and 3.0962(8) A, respectively. Cyclic voltammetry of 1–3 gave no reversible wave, but afforded some information supporting the presence of a dative bond.

Coordination Networks of a Ditopic Macrocycle Exhibiting Anion-Controlled Dimensional Changes and Crystal-to-Crystal Anion Exchange.

A rationally designed NO2S2-donor macrocycle L was synthesized, and anion variation (PF6(-), CF3CO2(-), NO3(-), and CF3SO3(-)) of its silver(I) complexes was employed as a strategy for controlling their coordination modes and network dimensions. The assembly reactions of L with four silver(I) salts afforded the complexes [Ag2L2](PF6)2 (1), [Ag4L2(CF3CO2)4]n (2), [Ag4L2(NO3)4]n (3), and {[Ag3L2(CF3SO3)2]CF3SO3}n (4) that adopt cyclic dimer, 1D, 2D, and pseudo 3D network structures, respectively, with the structure adopted depending on the coordination ability and coordination modes of the anion used. Interestingly, quantitative anion exchange accompanying an irreversible structural conversion from 2, 3, or 4 to 1 was observed in the crystalline state by powder X-ray diffraction (PXRD) and IR spectroscopy. A stepwise mechanistic process from 2 (CF3CO2(-), 1D) to 3 (NO3(-), 2D) by anion exchange was also proposed.

Endo- and Exocyclic Supramolecular Complexes of Mixed-Donor Macrocycles via [1:1] and [2:2] Cyclizations

A 20-membered N2O2S2 macrocycle (L(1)) and a 40-membered N4O4S4 macrocycle (L(2)) obtained from the mixed products via respective [1:1] and [2:2] cyclization are employed, and a comparative investigation of the coordination behavior of these macrocyclic ligands with nickel(II), cadmium(II), and silver(I) is reported. The X-ray structures of seven complexes (1-7) have been determined, and a range of structural types and coordination modes, including mono- to multinuclear and endo- to exocyclic coordination, is presented. The cation-dependent endocyclic 1:1 (metal-to-ligand) complex [Ag(L(1))]NO3 (1) and a sandwich-like 1:2 [Cd(L(1))2](NO3)2 (2) complex exhibiting different stoichiometries and metal positions in the complexes were obtained by the reactions of the smaller macrocycle L(1) with AgNO3 and Cd(NO3)2, respectively. Meanwhile, the reactions of L(1) with Ni(ClO4)2·6H2O and Ni(NO3)2·6H2O afforded the anion-dependent perching-type mononuclear solvato-complex [Ni(L(1))(CH3CN)3](ClO4)2·2CH3CN (3) and the sandwich-like complex [Ni(L(1))2(NO3)2] (4), respectively. In the complexations of the larger macrocycle L(2) with AgNO3, two endocyclic dinuclear complexes [Ag2(L(2))(CH3CN)2](NO3)2 (5) and [Ag2(L(2))](NO3)2 (6) with different coordination environments were isolated as a kinetic (5) and thermodynamic controlled (6) products in neutral condition. The identical reaction in acidic condition afforded a stairtype one-dimensional (1-D) coordination polymer {[Ag2(H4L(2))(μ2-NO3)(NO3)2](NO3)3·CH3CN·3H2O}n (7) in which the disilver(I) complex cation units are connected by nitrate ions. From these results, the effects of the cation, anion, and size ratio on the topologies of the resulting solid complexes are discussed. NMR titrations of L(1) and L(2) with silver(I) nitrate were also carried out to explore their complexation behaviors in solution and for comparison with the solid state structures.

Extra large macrocycle: 40-membered macrocycle via 2:2 cyclization and its dimercury(II) complex.

A large 40-membered N(4)O(4)S(4) macrocycle (L(2)) was obtained through a 2:2 cyclization of the corresponding dithiol and dichloride as a minor product during the preparation of a 20-membered N(2)O(2)S(2) macrocycle (L(1), 1:1 cyclization product). Each macrocycle was successfully separated from the mixed products and identified. The larger macrocycle L(2) allowed the preparation of its dimercury(II) complex, adopting a one-dimensional (1D) stairway-like polymeric chain linked with the anion. A monomercury(II) complex of the smaller macrocycle L(1) was also prepared. Both complexes and the larger macrocycle L(2) were structurally characterized by the single crystal X-ray analysis.

Combination of a new chiroptical probe and theoretical calculations for chirality detection of primary amines.

A method to determine absolute configurations of primary amines by combined use of a chiroptical probe 1 and theoretical calculations is reported. Probe 1 is linked to chiral primary amines yielding 1-amine conjugates, which exhibited exciton coupled circular dichroism in the m-quaterphenyl chromophores. The ratios between the P and M conformers of the 1-amine conjugates, which are calculated with DFT, were correlated highly with the sign and amplitude of the observed CD spectra.

Lithium ion selective dibenzo-14-crown-4 possessing a phosphoric acid functional group as a pendant

Abstract Dibenzo-14-crown-4 possessing an ionizable phosphoric acid moiety as an additional binding site of a pendant arm has been synthesized. Its complexing ability was measured by solvent extraction and transport experiment. It is disclosed that the introduction of the pendant group to the dibenzo-14-crown-4 provides a significant enhancement in the extractability and the transport rate toward only Li+ ion.

Syntheses and chemicophysical properties of macrocyclic compounds containing a ruthenocene unit

Abstract Synthesis and extraction ability of macrocyclic compounds containing ruthenocene as an integral part of the macrocyclic skelton are reported. Also, the complexes of the 1,n-dithiaoxa[n]ruthenocenophanes with transition metal cations were isolated.

Ligand-Induced Formation of Copper(I) Iodide Clusters: Exocyclic Coordination Polymers with Bis-dithiamacrocycle Isomers

A comparative study on the formation of guest clusters induced by different shapes (or sizes) of exocyclic binding sites embedded in the bis-macrocyclic host isomers is reported. CuI reacts with two regioisomers of a bis-dithiamacrocycle, o-bis-L (W-shaped binding site) and m-bis-L (U-shaped binding site), to yield one-dimensional coordination polymers {[(μ4-Cu4I4)(o-bis-L)]·2CH3CN}n (1a) and [(μ4-Cu2I2)(m-bis-L)]n (2). In 1a, the o-bis-L ligand isomer is linked by a spacious cubane [Cu4I4] cluster, while the m-bis-L ligand in 2 is linked by a smaller rhomboid [Cu2I2] cluster because of the different exocyclic binding sites. The results observed illustrate the possibility for the metal clusters including [CunIn] (n = 2 or 4) to adopt a controlled formation through the binding site alternation or design. Because of the adaptive cluster formations, the products show different photophysical properties. Additionally, sliding of the one-dimensional chains in 1a was observed upon loss of the lattice solvent molecules in ambient condition.

ALKYLPHOSPHORIC ACID ARMED CROWN ETHERS HAVING A SPECIFIC CATION BINDING ABILITY

Abstract The syntheses, transport via a bulk liquid membrane, and cation binding properties of alkylphosphoric acid armed crown ethers are reported. The new armed crown ethers and monoaza crown ether containing 13–19-membered crown rings are synthesized by two methods: (a) the reaction of a hydroxymethyl-substituted crown ether with dichloroalkylphosphate followed by hydrolysis; (b) the one-pot reaction of a hydroxymethyl crown ether with an alkylphosphate in the presence of dicyclohexylcarbodiimide-pyridine. The transport experiments reveal that (i) the alkylphosphoric acid armed crown ethers exhibit specific transport abilities for alkali metal cations which fit the cavity size of their crown rings, (ii) the structure of the bridgehead carbon which bears the pendant arm (trimethylene unit and dimethylene unit) significantly influences the cation selectivity, and (iii) for the zwitterion-type phosphoric acid armed monoaza crown ether the cation selectivities can be controlled by altering the aqueous phase in the liquid membrane transport system. Computer and CPK modelling suggested that the phosphoric acid site is a cooperative coordination site. Spectroscopic data ( 13 C nuclear magnetic resonance and IR) supported the proposed interaction of the cavity complexed crown ether with the side arm.

Construction of an M3L2A6 Cage with Small Windows from a Flexible Tripodal Ligand and Cu(hfac)3

An M3L2A6 cage has been prepared with small windows from a tripodal ligand, L, and Cu(hfac)2. Cold spray ionization mass spectrometry of a mixture of L and Cu(hfac)2 revealed the formation of a Cu3L2hfac6 cage in solution. X-ray crystallography showed that the Cu3L2hfac6 cage included neutral molecules such as THF and CHCl3. Furthermore, the six hfac anions have been shown to play an important role in holding neutral guest molecules securely in place.