Volume 49, Issue 4

The crystal structure of β-(NS(O)Cl) 3 is reported.

The crystal and molecular structure of the tetrameric complex of the composition [SbCl 3 ·OP(NCS) 3 ] 4 synthesized from SbCl 3 and OP(NCS) 3 in CCl 4 waso determined by X-ray crystallography [143 m space group, cubic system with a = 13.927(4) Å]. The complex exhibits a tetranuclear "cage" structure with a [Sb 4 O 4 ] core which consists of μ 3 -bridging oxygen and six coordinate antimony(III) atoms; the Sb-O distance, 3.060 Å, is exceptionally long.

In the reaction of 2-chloro-1,5-dimethyl-3-phenyl-1,3,5-triaza-2λ 3 -phosphorinane-4,6- dione (1) and 2-chloro-1,3,5-triphenyl-1,3,5-triaza-2λ 3 -phosphorinane-4,6-dione (2) with (2-chloroethyl)amine hydrochloride or bis(2-chloroethyl)amine hydrochloride in the presence of triethylamine the corresponding (2-chloroethyl)amino- and bis(2-chloroethyl)amino-substituted 2λ 3 -phosphorinane-4,6-diones (3-6) are formed. Oxidation with the hydrogen peroxide- urea-1: 1-adduct gives the corresponding 2-oxo-2λ 4 -phosphorinane-4,6-diones (7-10), in the same manner as described in the literature for the 1,3,5-trimethyl-1,3,5-triaza-2λ 4 -phosphorinane- 4,6-diones [6]. Hydrolysis of 1 leads to 2-hydro-1,5-dimethyl-3-phenyl-1,3,5-triaza- 2λ 4 -phosphorinane-4,6-dione (11). Compounds 3 -11 have been characterized via their 1 H, 13 C and 31 P NMR spectra, mass spectra, and, with the exception of 9, through elemental analyses.

The chiral ligand precursor systems [1-Cp 1 -R 1 -2-R 2 -2-Cp 2 ]ethane 5a-d bearing two different cyclopentadienyl fragments (Cp 1 , Cp 2 = Cp, Ind, Flu) and a variable bridge substitution pattern (R 1 , R 2 =H, Ph, cyclopentyl, cyclohexyl) were prepared starting from the corresponding epoxides. The solid state structures of six organic intermediates are reported in order to prove the stereochemistry of the ligand forming reactions. Treatment of the dilithio salts of 5a-d with ZrCl 4 in CH 2 Cl 2 afforded chiral ansa-zirconocene dichlorides (6a-d).

Difluoro(supermesityl)borane reacts with monolithiated hydrazines to give the correspond­ ing fluoroborylated hydrazines 1a-c , which could not be dehydrofluorinated to yield definite products. From dilithiated hydrazine the 1,2-borylated species 2 was obtained. The fluoro-borylhydrazones 3a-3d prepared in an analogous way, by dehydrofluorination with tert-butyllithium, led to 5-, 6-and 7-membered boron nitrogen heterocycles depending upon the substituents of the hydrazones.

The reaction of 1,1-bis(trim ethylstannyl)-2-m ethylpropene-1 and 1,3-bis(dichloroboryl)- propane leads to the chloro derivate of 6,6-dimethyl-2-m ethylidene-1,3-diboracyclohexane (1a), in which the Cl atoms are substituted by the dimethylamino and the methyl group to yield lb and 1c . Similarly the benzo-1,4-diboracycloheptene-2 derivative 2a is obtained from 1,2-C 6 H 4 (SnMe 3 ) 2 and (Cl 2 B) 2 C 3 H 6 . Replacement of the substituent leads to the dimethylamino (2b) and methyl derivatives (2c). Redox reaction between hexyne-3 and (I 2 B) 2 C 3 H 6 results in the formation of 1,4-diiodo-2,3-diethyl-1,4-diboracycloheptene-2 (3a), which is methylated to give 3c. The constitutions of 1a-c, 2a-c and 3a,c are derived from NMR and MS data and are confirmed by X-ray structure analyses for 1b and 2b.

By reaction of [B 6 H 6 ] 2- with chloroacetonitrile in dichloromethane the cyanomethylhexahy-dro-closo-hexaborate(1-), [B 6 H 6 (CH 2 CN)] - is formed. The com pound has been separated from excess [B 6 H 6 ] 2- by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structure of [P(C 6 H 5 ) 4 ][B 6 H 6 (CH 2 CN)] has been determined by single crystal X-ray diffraction analysis; triclinic, space group P1 with a = 7.503(3), b = 12.0949(8), c = 14.6572(11) Å α = 79.399(6)°, β = 79.19(2)°, γ = 89.2(2)°. The 11 B NMR spectrum is consistent with a mono hetero substituted octahedral B6 cage. In the 13 C NMR spectrum of Cs 2 [B 6 H 5 (CH 2 CN)] a singlet at 131.9 ppm (CN) and a quartet at 2.97 ppm with 1 J(C,B) = 54.7 Hz (CH 2 ) are observed. The IR and Raman spectra exhibit a very strong CN stretching band at 2218 cm -1 .

Initiation of the reaction between Na 3E (E = As, Sb, Bi) and anhydrous metal halides at 25 to 550 °C produces metal arsenides M x As y (M=Y,La, Ti, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Pt ,Cu and Zn) and antimonides M x Sb y (M=Ti, V, Nb, Ta, Cr, Fe, Co, Ni, Pt, Cu and Zn) via an exothermic selfpropagating reaction. The metal arsenides were characterized by X-ray powder diffraction, SEM/EDAX , microanalysis and FT-IR.

Chiral chelate complexes with dianions of 2-hydroxyiminocarboxylic acids (1) und (2) are obtained by deprotonation of the compounds and in the presence of a donor ligand (Do=PR 3 , P(OMe) 3 , py). The structure of has been determined by X-ray diffraction.

The reaction of trimethylamine, H 2 S, and sulfur in ethanol yields orange crystals of bis(trimethylammonium) hexasulfide. The com pound crystallizes in the centrosymmetric monoclinic space group P 2/c. The lattice constants are a = 10.310(7), b = 5.752(2), c = 13.348(10) Å, β = 98.41(6)°. The S 2 6 -chain has a helical all-trans-conformation (sequence of the signs of torsion angles +++ and --- ).

Ten palladium and platinum complexes each containing two chelating bis(diaminocarbene) ligands have been synthesized in a one pot-reaction from PdI 2 , PtI 2 or K 2 PtCl 4 , a tenfold excess (forty equivalents) of isocyanide and 1,2- or 1,3-diamines. An X-ray investigation of (8) revealed a stereochemistry with the two spiro-linked seven-membered metallacycles strongly bending out of the PtC 4 coordination plane in opposite directions. In addition, three palladium bis-chelates with mixed amine/carbene bidentate ligands were obtained from reactions of PdI 2 with only four equivalents of isocyanide and the diamine.

Sr 3 [Al 2 N 4 ] (Pnna, Nr. 52; a = 590.1(3), b = 1000.5(5), c = 958.0(4) pm; Z = 4) was prepared from the elements (molar ratio Sr: Al = 3:1; reaction with N 2 , 1 atm, 24 h; T max = 1100 °C). The crystal structure contains corrugated chains 1 ∞ [AlN 4/2 3- ] which consist of distorted AlN 4 tetrahedra sharing common edges (Al-N : 188.5(7)-195.8(7) pm; N-Al-N : 95.0(3)- 126.0(5)°). The nitrogen atom s form a distorted ccp arrangement. 3/4 of the octahedral holes are occupied by Sr atoms; 1/4 of the tetrahedral holes are occupied by Al atoms. Sr 3 [Al 2 N 4 ] can be described in terms of the Zintl concept (isosteric relation of [AIN 2 ] 3- to SiS 2 ).

The donor-acceptor complexes PPh4[Cl(succinimide)2] and PPh4[Cl(N-chlorosuccinimide)2] have been prepared by reactions of PPh4Cl with succinimide and N-chlorosuccinimide, re­ spectively. in acetonitrile solutions. The complexes have been characterized by IR spectros­ copy and by crystal structure determinations. The crystal structure of N-chlorophthalimide has also been solved.

Sensitized photooxidation of 4-phenyl-1,2-dithiolane 1 has been studied. Reacting it with 0.5 mole equivalents o f singlet oxygen, a mixture of 1, 4-phenyl-1,2-dithiolane-1-oxide 2, and 4-phenyl-1,2-dithiolane-2-dioxide 3 is produced. Using one mole equivalent of singlet oxygen, 3 is obtained in high yields. The chemical oxidation of 1 using H 2 O 2 /HOAc yields pure 2. With 2 a diastereoselectivity of 10:1 is observed. The oxidative addition of 1 to L 2 Pt(η 2 -C 2 H 4 )[L=PPh 3 (4), 1/2 dppe (5)] leads to the 3-phenyl-propane dithiolato complexes 6a,b. The platinum(O) com pound 4 reacts with 2 to give the bimetallic compound 7 and the monometallic species . These complexes contain the 3-sulfido-l-(2-phenyl)-propanesulfenato ligand. All com pounds have been characterized by their spec­ troscopic data.

Syntheses and structures of homoleptic 1,4-diaza-1,3-diene (DAD) complexes of titanium are described. The spiranoid DAD complexes of formula (DAD) 2 Ti 3a-c are formed by reaction of TiCl 4 ·2THF with the disodium salts Na 2 DAD 2a-c or by reduction of TiCl 4 ·2TH F with magnesium in presence of two equivalents of DAD 1a-c . The endiaide complexes 3a-c are thermally stable, very sensitive to oxygen and water, and soluble in all com monorganic solvents. An X-ray crystal structure determination of 3 c reveals the titanium atom to be in a strongly distorted tetrahedral environment. The two five-membered metallacyclic rings are folded along the N,N′ axis. Temperature-dependent 1 H NMR spectra of 3a-c indicate a rapid intramolecular inversion of this non-planar ring system in solution even at room temperature. Reduction of TiCl 4 ·2THF with magnesium in presence of excess DAD 1d-f leads to the formation of the blue-violet complexes (DAD) 3 Ti 4d-f. At low temperatures three sterically crowded DAD ligands cause a rigid conformation as demonstrated by their unique lowtemperature 1 H NMR spectra.

Tetraphenyl-p-benzoquinone, according to its single crystal structure, shows some steric congestion: its quinone ring is distorted by 7° to a chair conformation, and its phenyl substituents are twisted around their CC axes between 46° and 72°. The half-wave reduction potentials of -0.57 and -1.25 V in acetonitrile confirm negligible π interaction of the phenyl substituents. Addition of alkalimetal tetraphenylborate salts lowers the second reduction potential due to contact ion formation, which can be confirmed by UV/VIS spectra recorded under aprotic conditions. Extensive ESR/ENDOR investigations prove the formation of the following species in THF solution: Tetraphenyl-p-benzosemiquinone radical anion contact ion pairs [M ·⊖ Me ⊕ solv ]' (Me ⊕ : Li ⊕ , Na ⊕ , Rb ⊕ , Cs ⊕ ) and contact triple ion radical cations both with identical cations [M ·⊖ (Me ⊕ solv ) 2 ] ·⊕ (Me ⊕ : Li ⊕ , Na ⊕ , Cs ⊕ ) and different cations [M ·⊖ (Li ⊕ solv )(Me ⊕ solv )] ·⊕ (Me ⊕ : Na ⊕ , Cs ⊕ ). Addition of crown ethers can lead to external solvation of the Me ⊕ counter cations, whereas cryptands form internal solvation complexes. The radical anion of 2,6-diphenyl-p-benzosemiquinone adds cations at its phenyl-free molecular half. The radical anion salt [tetraphenyl-p-benzosemiquinone ·⊖ (Na ⊕ (tetrahydropyrane) 2)] could be crystallized and its structure determined at 200 K. In agreement with the Hirota sign rules for contact radicals in solution, the Na ⊕ ion is found 62 pm above the π plane and 29° outside the axis of the CO bound, which is elongated due to one-electron reduction by 5 pm to 127 pm.

While the S-alkyl- or S-phenyl-2,3-butadienethioates 4 a-c are synthesized via the usual “Wittig ylide way”, the corresponding 2-methyl-2,3-butadienethioates 9 a-d and the 2-methyl-4.4-diphenyl-2,3-butadienethioates 9 e,f are obtained by condensation of the allenic acids 7 a,b with the thiols and thiophenols 8 in the presence of dicyclohexylcarbodiimide (DCC) and a catalytic am ount of 4-dimethylaminopyridine (DMAP). In contrast to N- or O-phenyl 2,3- butadienamides or -esters, resp., the phenyl derivatives of 4 and 9 do not undergo the intram olecular Diels-Alder reaction, but by heating, all representatives of 4 only decompose, while 9 a-d and 9 e,f rearrange to 3-alkyl(aryl)thio-2-cyclobuten-1-ones 12a-d and to 3-arylthio- 1-naphthols 14a, b, resp. Heating of the cyclobutenone 12d in the presence of N-methylaniline furnishes the 2-butenanilide 16. On reacting 1-phenylthio-1-propyne 17 with diphenylketene 18, the diphenylacetate 19 is isolated, where the naphthol derivative 14a represents the ester moiety.

The complexes of some 2-spirothiazolid-4-one derivatives have been prepared with Cu(II), N i(II), C o(II) and Cd(II) salts. The complexes all have a metal to ligand ratios of 1:1 or 1:2 and are all believed to have tetrahedral structures with chelating ligands. Their structures are suggested on the basis of analysis, X-ray diffraction techniques, spectral (UV-VIS, IR, 1 H NMR), and thermal decomposition as well as conductivity measurements. The ligands are coordinated to the metal ions as monovalent bidentate ligands through the OCO groups. Electrical conductivity studies indicated that these complexes have activation energies in the range of semi-conducting materials. It is observed that some of the complexes are m ore potent as bacteriostatic agents than the free ligands.

Aminoguanidine is not only an agent with a variety of pharmacological effects but also an important starting material of am idinohydrazone-type drugs and enzyme inhibitors. There­ fore, we have now synthesized am inoguanidine sulphate CN 4 H 8 2+ .SO 4 2- and determined its structure by single-crystal X-ray diffraction. The doubly protonated (dication) form of amino­ guanidine that is present in the sulphate could, in principle, exist in the form of several different tautom ers. The crystal studied consisted exclusively of one tautomer: one of the nitrogens of the hydrazine moiety bears three hydrogen atoms while the other one (the one bound to the carbon) bears one hydrogen. The other two nitrogens are bound to two hydrogens each. The predominance of this tautomer can be explained by the very strong resonance in it. The dication of aminoguanidine is remarkably planar. The hydrogens of the hydrazine moeity are, however, clearly out of the plane of the other atoms. There is a strong hydrogen bond between the proton of the m onoprotonated nitrogen and one sulphate oxygen. This bond obviously causes the deviation of the hydrogen from the plane. The bonds between the carbon atom and the adjecnt nitrogens are essentially equally long, indicating that each bond has approximately the same amount of double bond character. One of the positive charges of the dication is thus delocalized, being shared by all of the atoms of the CN 3 moiety. In this respect, the structure is similar to that of all bis(amidinohydrazones) whose structures have been determined. The other positive charge of aminoguanidine dication is localized at the nitrogen bearing three hydrogens.

The isomerization of roccellic acid to threo-roccellic acid has been investigated. Reduction of dimethyl roccellate with LiAlH 4 gave the corresponding diol which yielded on oxidation with Jones' reagent two isomeric γ-lactones. 1-Methyl roccellic amide has been transformed by a photochemical reaction to the δ-lactone acaranoic acid. Two copper complexes of roccellimide have been prepared.

The synthesis of the stereoisomeric esters of L- and D-N-benzoylalanine and L- and D-Nbenzoylalaninol is described.

Crystals of the title com pound were obtained after reaction of tetraethylam monium-hydroxooxalato-titanate(IV ) with tetraphenylarsonium - chloride in water. The crystals are orthorhombic, space group P nma with a = 16.288(2) Å, b - 10.708(3) Å, c = 12.787(3) Å, Z = 4 ,V = 2230.2 Å 3 .