Helmut Paulus

On the configuration of open chain α-sulfonyl carbonions: X-ray crystal structure of [(phenylsulfonyl)isopropyllithium-diglyme]2 and [(α-phenylsulfonyl)-α-(methyl)benzyllithium-diglyme]2

Abstract The solid state structure of [(phenylsulfonyl)isopropyllithium- diglyme]2 (2d) and of [(α-phenylsulfonyl)-α-(methyl)benzyllithium-diglyme]2 (2e) is described. Whereas in dialkyl substituted 2d the anionic C-atom is strongly pyramidalized it is almost planar in phenyl substituted 2e. A rationalization of this observation is proposed within the MO model for α-sulfonyl carbanions.

Crystal and molecular structure and magnetic properties of a tetrameric copper(II) complex with 3-hydroxy-4-[4′-(3″,4″-dichlorophenyl)-4′-hydroxy-2′-azabut-1′-en-1′-yl]-5-hydroxymethyl-2-methylpyridine (H2L2), [(CuL2)4]·9CH3OH

The crystal and the molecular structure of the title compound has been determined using three-dimensional X-ray diffractometer data involving 7 045 independent reflections. The compound crystallizes in the monoclinic space group I2/c with eight formula units [(CuL2)4]·9CH3OH in a unit cell with dimensions a= 27.062(5), b= 25.062(5), c= 26.390(5)A, and β= 92.39(1)°. The structure has been calculated by direct methods and refined by least-squares methods to a final R value of 0.054. In the cubane structure (C1 symmetry) each copper atom is bonded to one deprotonated phenolic oxygen, one imine nitrogen, and three deprotonated alkoxo-oxygen atoms giving a distorted square-pyramidal co-ordination. The six copper–copper distances are in the range 3.021(1)–3.492(2)A(mean 3.254 ± 0.184 A). Within the Cu4O4 core there are eight shorter copper–oxygen distances [1.917(5)–2.057(5)A, mean 1.983 A] and four longer ones [2.327(5)–2.690(6)A, mean 2.496 ± 0.166 A]. There are 72 methanol molecules per unit cell which are easily lost in air, giving an amorphous powder. The magnetic properties of the complex can be explained using the isotropic Heisenberg–Dirac–van Vleck model. The exchange parameters for the complex with approximate S4 symmetry obtained (J12=–9.9 ± 3.0 cm–1, J13= 20.5 ± 3.0 cm–1, and g= 2.08 ± 0.02) are in good agreement with those of similar substances and show the presence of both ferromagnetic and antiferromagnetic interactions. The amorphous modification shows a predominant ferromagnetic interaction.

Crystal structure and magnetic properties of a tetramer with a step-like Cu4N4O2 core containing asymmetric bridged dimeric subunits related to the hemocyanin copper active site

Abstract The Cu(II)-derivate of the macrocycle L derived from 2-hydroxy-5-methylisophthalaldehyde and 3- dimethylamino-1-propylamine forms tetranuclear {[LCu 2 (N 3 ) 3 ](ClO 4 ) 2 } 2 units. The crystal structure determined by X-ray crystallography is based on a step-like Cu 4 N 4 O 2 -core with interdimeric μ(1)-azido bridging. The tetramer is formed from two dimeric subunits which are connected by a center of symmetry. The subunits are asymmetric bridged dkneric complexes with a phenolate and μ(1)-azido bridge. The coordination polyhedra around the two copper atoms are 4 + 2 and 4 + 1 including one coordinating perchlorate ion. The magnetic susceptibility of the complex has been measured in the temperature range 4.2 K to 315.6 K. The theoretical analysis using models for tetrameric and dimeric interactions revealed only a small interdimeric interaction. The magnetic exchange coupling of the asymmetric bridged dimeric unit (2 J = −528 cm −1 ) is comparable to that of known di-oxygen bridged dimers. The results are related to the magnetic behaviour of the asymmetric bridges found in the binuclear copper sites in hemocyanin. Infrared measurements have been taken and there is a discussion of the asymmetric vibrations of the three different azido-groups.

Mesophase behaviour of 2,5-dibenzoyloxy-p-benzoquinone derivatives and tetrahydrobenzene tetraesters

Abstract The synthesis of 2,5-dibenzoyloxy-p-benzoquinone derivatives, their products after reduction and tetraesters from tetrahydroxybenzene prepared from those products is described. Their phase behaviour was investigated by differential scanning calorimetry and polarizing microscopy and is discussed in terms of their detailed structure.

Die Kristallstruktur von 1,2-Diferrocenylethanen

X-ray crystal structure analyses of stereoisomeric 1,2-dimethyl and diphenyl 1,2-diferrocenyl ethanes (1,2) as well as of 1,1,2,2-tetraferrocenyl ethane (3) showed that racemic (threo) and meso (erythro)2 adopt conformations with antiperiplanar arrangement of the ethane H-atoms (andC2 andCi symmetry, resp.), whereas1 and3 prefer the synclinal (skew) conformations. In3 the torsional angle between the ethane H-atoms is increased to appr. 90°;3 represents a chiral structure withC2 symmetry.For the conformation of tetraferrocenyl ethane (3) in solutionC2 symmetry could be deduced from the13C-nmr. spectra.The conformations of the diferrocenyl ethanes are discussed and compared with those of corresponding alkyl and aryl ethanes.

The absolute chirality of (+)-12-Bromo-[2.2]metacyclophane-4-carbonitrile

The absolute configuration of (+)-12-bromo-[2.2]metacyclophane-4-carbonitril [(+)-4 e] was determined by theBijvoet X-ray diffraction method as(R)p (Fig. 1). This result allows the unambigous assignment of the absolute chiralities of all optically active 4-monosubstituted, 4,14-homodisubstituted, 4,12- and 4,14-heterodisubstituted [2.2]metacyclophanes chemically correlated with (+)-4 e. The result is compared with those obtained by other methods for establishing the absolute configuration.ZusammenfassungDie absolute Konfiguration von (+)-12-Brom-[2.2]metacyclophan-4-carbonitril [(+)-4 e] wurde mit Hilfe der anomalen Röntgenbeugung (Bijvoet-Methode) als(R)p (Fig. 1) ermittelt. Damit sind auch die Konfigurationen aller optisch aktiven 4-monosubstituierten, 4,14-homodisubstituierten sowie der 4,12- und 4,14-heterodisubstituierten [2.2]Metacyclophane bekannt, die mit (+)-4 e eindeutig chemisch korreliert sind. Dieses Ergebnis wird mit jenen verglichen, die mit Hilfe anderer Methoden zur Konfigurationsermittlung erhalten wurden.

Synthese, Kristallstruktur und Konformation vontrans-[2.2](1,2)Ferrocenophan und seinen 1-Hydroxyderivaten

Starting from1-(dimethylaminomethyl)-2-iodo-ferrocene (3) [2.2](1,2)ferrocenophane (2) was prepared in an 8-step synthesis with 17% overall yield. Both from the oxoderivative12 and the ferrocenophane2 puretrans-isomers (12b and2b, resp.) were obtained; the former (12b) was reduced to a separable mixture ofexo andendo1-hydroxy-ferrocenophanes13a andb, resp. (∼ 3:7), the configurations of which were assigned by the LIS-method.X-ray crystal structure analysis of2b revealed a centrosymmetrical chair conformation. From1H- and13C-NMR spectra both for2b and for the hydroxyderivatives13 a rigidexo-exo chair conformation was deduced.

X-ray structures and properties of five-coordinate copper(II) complexes with a quadridentate N4 ligand and with a quinquedentate N5 ligand

Complexes Cu(biquinen)(H2O)(BF4)2 (1), Cu(biquinen)(H2O)(ClO4)2 (2) and Cu(biquidien)(ClO4)2 (3) with the N4 Schiff base biquinen (1,2-bis(8-quinolylmethyleneimino)ethane) and with the N5 Schiff base biquidien (1,5-bis(8-quinolylmethyleneimino)-3-aza-pentane) were prepared. 1 crystallizes in the trigonal space group P32 with a=1018.0(3), c=2032.2(7) pm and Z=3; 2 in the monoclinic space group Cc with a=1865.7(9), b=995.1(5), c=1715.7(8) pm, β=128.59(2)° and Z=4; 3 in the triclinic space group P with a=1419.6(8), b=1095.8(6), c=917.7(6) pm, α=74.16(2), β=75.55(2), γ=88.95(2)° and Z=2. In all three complexes the copper is five-coordinate with a N4O set of donor atoms in 1 and 2 and a N5 set of donor atoms in 3. The coordination geometry of the chromophors Cu(biquinen)(H2O)2+ in 1 and 2 and Cu(biquidien)2+ in 3 is distorted trigonal bipyramidal, with the water in 1 and 2 being coordinated in an equatorial position. In aqueous solution 1 and 2 give the same Vis absorption spectrum with a broad band at 609 nm, whereas for 3 this weak due5f8d band is shifted to 578 nm. In water/dioxane (3:1) the imine nitrogens of the Schiff base biquinen have pKa values of 9.25 and 6.63, respectively (I=0.5 M NaClO4; T=25 °C).

X-ray structure analysis of the cobalt(III) complex formed with the ambidentate ligand 3-hydroxyiminopentane-2,4-dione: proof for N,O-fac-coordination and resonance charge delocalization

Abstract The complex [Co(inaa) 3 ] (inaa=anion of 3-hydroxyiminopentane-2,4-dione) crystallizes in the triclinic space group P 1 with a =1549.8(8), b =1174.2(6), c =1127.1(5) pm, α=111.95(2), β=94.73(2) γ=90.71(2)° and Z =4. The three ambidentate ligands are attached to the Co through N and O atoms, forming five-membered chelate rings. The N 3 O 3 set of donor atoms forms a distorted octahedron around the Co with the three N and O atoms being in a facial arrangement. The unit cell contains two pairs of enantiomers. The analysis of bond lengths points to strong resonance charge delocalization within the coordinated ligands.

Template synthesis and molecular structure of the nickel(II) perchlorate-chloride complex with tris(((aminoisopropyl)amino)methyl)amine

Abstract The template condensation reaction of NiCL 2 · 6H 2 O with ammonia, formaldhehyde and 1,2-propylenediamine has been studied. The new Ni(II)-tris- (((aminoisopropyl)amino)methyl)amine complex was formed in the reaction. The compound has been investigated by elemental analysis, magnetic measurements, IR and UV-Vis spectra. Results suggested a semisepulchrate-type structure. This is confirmed by X-ray structure determination. At 295 K the crystals are regular space group P 2 1 3, a = b = c = 12.870(3) A, V = 2131(3) A 3 , Z = 4, D calc = 1.46 g cm −3 , D meas = 1.47 g cm −3 .