The first triple thiol-thiolate hydrogen bond versus triple diselenide bond that bridges two metal centers

Treatment of fac(S)-[Rh(aet)3] (aet = 2-aminoethanethiolate) with aqueous HBF4 in air led to the protonation at coordinated thiolato groups to give a rhodium(III) dimer, [{Rh(aet)2(Haet)}{Rh(aet)(Haet)2}](BF4)3 ([1](BF4)3). On the other hand, similar treatment of fac(Se)-[Rh(aes)3] (aes = 2-aminoethaneselenolate) produced a dinuclear rhodium(III) complex, [Rh2(selenocystamine)3](BF4)6 ([2](BF4)6), because of the autoxidation of coordinated selenolato groups by air. The crystal structures of [1](BF4)3, DeltaDelta-[1](BF4)3, and [2](BF4)6 were determined by X-ray crystallography. In [1]3+ two RhIII octahedrons are connected through a strong triple thiol-thiolate S-H...S hydrogen bond, while two RhIII octahedrons are directly joined by a triple diselenide bond in [2]6+. The cyclic voltammetry indicated that in acidic media the RhIII center in fac(Se)-[Rh(aes)3] is more easily oxidized to RhIV than that in fac(S)-[Rh(aet)3], which is responsible for the formation of coordinated diselenide bonds.     

The structure of prostaglandin B1 dimer

Dimeric derivatives of prostaglandin B₁ were prepared under alkaline conditions and the structures were determined by NMR spectroscopies.     

Structure of moracenin B,a hypotensive principle of Morus root barks

From the crude drug “sōhakuhi”, the root barks of Morus plants, a new derivative of isoprenoid flavones, moracenin B, showing hypotensive activity has been isolated and the structure has been determined as I on the basis of chemical and physical evidence.     

Structure of kukoamine A,a hypotensive principle of Lycium chinense root barks1

From the crude drug “jikoppi”, the root barks of Lycium chinense, a novel spermine alkaloid, kukoamine A, showing hypotensive activity has been isolated and the structure has been determined as that represented by formula I on the basis of chemical and physical evidence.     

New partially oxidized 1-D platinum chain complexes consisting of carboxylate-bridged cis-diammineplatinum dimer cations

The first/second examples of partially oxidized 1-D platinum chain compounds consisting of cationic dimer units have been obtained from electro-oxidation of an aqueous solution containing cis-[Pt(NH3)2(OH2)2]2+ and acetate/propionate. The analytical and crystallographic studies reveal the mixed-valency of Pt(2.2+)infinity. The XPS confirms the presence of both Pt(II) and Pt(III). The solid-state physical measurements reveal that they are diamagnetic semiconductors and display a fairly broad, low-energy absorption band in the range of 500-3200 nm.     

On Some Harris-FKG Type Correlation Inequalities for a Non-Attractive Model

We consider the following non-attractive one-dimensional model whose evolution is given by ξ_n+1(x)=ξ_n(x+1)+ξ_n(x?1) (mod 2) with probability p, =0 with probability 1?p. In the present letter, we prove that some Harris-FKG type correlation inequalities hold for this model. Moreover it is shown that a correlation inequality is also correct for the more general non-attractive class.     

Double Shrinkage Estimators in the GMANOVA Model

In the GMANOVA model or equivalent growth curve model, shrinkage effects on the MLE (maximum likelihood estimator) are considered under an invariant risk matrix. We first study the fundamental structure of the problem through which we decompose the estimation problem into some conditional problems and then demonstrate some classes of double shrinkage minimax estimators which uniformly dominate the MLE in the matrix risk.