bluuebunny/crossref_metadata_2025_split huggingface dataset:
Umsetzung einiger Dihydrobenzoxazaphosphorinone mit Nucleophilen; ungewöhnliche Oxidations‐, Insertions‐ und Umlagerungsprodukte und deren Charakterisierung durch Einkristall‐Röntgenstrukturanalyse
Authors: Neda Ion , Fischer Axel , Kaukorat Thomas , Jones Peter G. , Schmutzler Reinhard 
Published: July 2007

AbstractReaction of some Dihydrobenzoxazaphosphorinones with Nucleophiles; Unusual Oxidation, Insertion, and Rearrangement Products and their Characterisation by Single‐Crystal X‐Ray AnalysisThe reaction of 2‐chloro‐1,2‐dihydro‐1‐methyl‐4H‐3,1,2‐oxazaphosphorin‐4‐one (2) and its 2‐diethylamino‐substituted derivative 3 with various nucleophiles yielded novel and sometimes unexpected products. Hydrolysis of 2 furnished the 2‐hydroxybenzoxazaphosphorinone 4. In the presence of small amounts of water, two molecules of 4 were transformed into 5, accompanied by cleavage of one of the heterocyclic rings. The reaction of 2 with sodium chlorodifluoroacetate led, possibly in an Arbuzov‐type reaction, to compound 6. The 1,5‐diaza‐4,8‐cyclooctanedione system 7 was formed by reaction of 2 with 1,2,4,5‐tetrakis(trimethylsilyloxy)benzene with concomitant loss of the phosphorus‐containing group. 2,2′‐Bis(trimethylsiloxy)biphenyl reacted with 2 in the expected fashion to form the diphosphorus compound 8. From 8 the chlorogold(I) complex 9 was obtained. The reaction of 3 with tetrachloro‐ and tetrabromo‐o‐benzoquinone did not lead to the expected spirocyclic products by oxidative addition of the quinone system to λ3P. Instead, cleavage and expansion of the heterocyclic ring system with formation of the tricyclic derivatives 10 and 11 took place. Compounds 5‐10 were subjected to X‐ray structure analysis. Compound 5 exists as two modifications 5a and 5b, which differ mainly in the relative orientation of the phenyl rings; intramolecular N–H…O hydrogen bonds are observed. Bond lengths at the halo‐substituted carbon atom in 6 indicate steric crowding. The central 8‐membered ring of 7 displays a “tub” conformation. Compound 8 undergoes a conformational change on complexation to the two gold(I) centres; one of the torsion angles C‐O(exocyc.)‐P‐N is ‐163° in 8, but 95° in 9. The structure determination of 10 served only to confirm the (unexpected) connectivity; the crystal quality was too poor to allow quantitative conclusions.
Zur Addition von Alkyldichlorboranen an Bis(η5‐cyclopentadienyl)dihydridowolfram
Authors: Braunschweig Holger , Wagner Trixie 
Published: July 2007

AbstractOn the Addition of Alkyldichloroboranes to Bis(η5‐cyclopentadienyl)dihydridotungstenReaction of basic [Cp2WH2] (1) with the Lewis acids iPrBCl2 and tBuBCl2 does not lead to adducts of the type [Cp2WH2 (RBCl2)] [R = iPr, tBu]. The zwitterions [CpWH3(η5‐C5H4BRCl2)] (R = iPr, 2a; tBu, 2b) having an exocyclic boron substituent were isolated instead in 60% yield. The molecular structure of 2b crystallizing in the space group P21/n is proved by X‐ray structure determination.
Preparation of [5 + 6]‐, [6 + 6]‐, and [6 + 7]‐Bicyclic Guanidines from C,C'‐Bis(iminophosphoranes)
Authors: Molina Pedro , Obòn Rosario , Conesa Carlota , Arques Antonio , De Velasco M. Los Desamparados , Llamas‐Saiz Antonio L. , Foces‐Foces Concepciòn 
Published: July 2007

AbstractA one‐pot synthesis of [5 + 6]‐, [6 + 6]‐, and [6 + 7]‐rigid bicyclic guanidines (6, 8, 19, 21, 23) based on a bis(iminophosphorane)‐mediated annulation strategy is reported. The crystal and molecular structure of the parent [5 + 6]‐bicyclic guanidine 8 has been established by X‐ray diffraction. The crystallographically independent molecule forms dimers through a centre of symmetry by N–H–N hydrogen bonds. The molecule, and therefore the dimer, is statistically disordered in a 65/35 ratio. A statistical study of N–H–N hydrogen bonds of this kind of dimers has been carried out by using the Cambridge Structural Database.
[3.3]Isoalloxazinophanes and Arene‐Bridged Bis(isoalloxazines): Syntheses, Characterizations and Properties Related to Intramolecular Interactions
Authors: Staab Heinz A. , Kirsch Peer , Zipplies Matthias F. , Weinges Alexa , Krieger Claus 
Published: July 2007

AbstractIn order to study the orientation and distance dependence of π … π interactions between flavins in various redox states, two approaches to bis(isoalloxazine) model compounds are presented: The [3.3]isoalloxazinophanes 2 and 4 and the rigid single‐bridged 1,8‐naphthalene‐ and 1,8‐anthracene‐linked bis(isoalloxazine) systems 6, 8 and 26 were synthesized, characterized, and studied by spectroscopic methods and cyclic voltammetry. The experimental data are discussed in comparison with “monomeric” isoalloxazines and flexible single‐chain trimethylene‐linked bis(isoalloxazine) reference compounds. X‐Ray structure analyses are reported for the 1,8‐bis(isoalloxazinyl)‐9,10‐dihydroanthracene 26 and for 22 as an example of 1,8‐disubstituted naphthalenes with strongly polar substituents comparable to 6.
Zur Reaktion von Bis(trimethylphosphan)titanocen mit Ketonen
Authors: Gleiter Rolf , Wittwer Wolfgang 
Published: July 2007

AbstractOn the Reaction of Bis(trimethylphosphane)titanocene with KetonesFulvenes are the products of the reaction of aliphatic and aromatic ketones with bis(trimethylphosphane)titanocene in nonpolar solvents, but no formation of pinacols is observed. The mechanism is discussed.
Umlagerung und Abbau bicyclischer Amin—Tetraorganodiboroxane[1]
Authors: Köster Roland , Schüßler Wilhelm , Seidel Günter , Bläser Dieter , Boese Roland 
Published: July 2007

Rearrangement and Degradation of Bicyclic Amine‐Tetraalkyldiboroxanes[1]The amine‐tetraalkyldiboroxanes [1a: R1,4,7,7′ = Et; 1b: R1,4,7 = Et, R7′ = Ph; 1b′: R4,7,7′ = Et,R1 = Ph; 1c: R1,7,7′ = Et, R4 = Ph] react on heating by EtBO elimination and allylborane rearrangement to yield the allyl‐aminoboranes Me2NB(Et)CH2C(R4)=C(R7,7′) [2a: R4,7,7′ = Et; 2b/2b′: R4 = Et, R7,7′ = Et, Ph; 2c: R4 = Ph, R7,7′ = Et]: On heating above 60°C the diastereomeric syn/anti‐Id/1d′(Id: R1,7 = C8H14, R4,7′ = Et; 1d′: R1,7′ = C8H14, R4,7 = Et) give the unsaturated rac‐amino‐trialkyldiboroxane (rac‐3) (X‐ray structure analysis) by intramolecular 1,2‐deaminoboration. rac‐3 is characterized by reaction with (Et2BH)2 and (Et2BD)2 with formation of the 1,2,6‐oxadiborinane 5 by evolution of H2 or HD respectively. The intramolecular CH‐borylation of rac‐3 is compared with those of the thujopsen hydrocarbons I–III.
Einfluß der Reaktionsbedingungen auf die enantioselektive Protonierung von Lacton‐Enolaten
Authors: Gerlach Uwe , Haubenreich Thomas , Hünig Siegfried 
Published: July 2007

Stereoselective Protonation of Carbanions, 5[1]. — Effects of Reaction Conditions on the Enantioselective Protonation of Lactone Enolates[2]Protonation of the enolates 1Li and 2Li by using standard conditions yields enantioselectivities up to 54 and 50% ee, respectively, depending on the chiral proton source[1]. These values may change dramatically by the following variations (standard ee's in parenthesis): (i) In Et2O/THF (90:10) (S)‐2 with 72% ee (44%) is formed with (R)‐pantolactone (3) but only 48% ee (39%) with (R,R)‐tartaric ester 4 (Figure 1). (ii) Lewis acids may produce rac‐2 (SnCl2, MgBr2) or definitely increase the enantioselectivity: With lactone 3: 46% ee (44%); with esters 4: 48% ee (39%); with bissulfonamide 7: 67% ee (47%) (Table 1, 2). (iii) Lithium chloride (2–4 equiv.) in THF yields (S)‐1 with 68% ee (47%) and (S)‐2 with 77% ee (39%) but only if ester 4 ist employed as chiral proton source (Figure 2). (iv) Chiral Lewis bases create (S)‐2 with up to 30% ee on protonation with achiral acids (Table 3, 4). (v) Deuteration of 2Li ranges from 16 to 95% depending on the nature of the base as well as the deuteron source. The degrees of deuteration and enantioselectivity are not correlated. All results demonstrate the complexity of enantioselective protonation of enolates which still needs empirical optimization.
A Convenient Synthesis of Enantiomerically Pure Ethylene‐Bridged Metallocene Complexes Bearing Fluorenyl‐ and Octahydrofluorenyl Ligands[1]
Authors: Rieger Bernhard , Jany Gerhard 
Published: July 2007

AbstractRing opening of (R)‐(–)‐epoxystyrene (1) with fluorenyllithium leads to the optically active alcohol 2 in high yield. Derivatization of 2 to the trifluoromethanesulfonate 4 and subsequent reaction with one equivalent of fluorenyllithium gives the ligand precursor (1S)‐1,2‐bis(9‐fluorenyl)‐1‐phenylethane (5), which is used for the synthesis of [(1R)‐1,2‐bis(η5‐9‐fluorenyl)‐1‐phenylethane]ZrCl2 (6).
Synthese und Eigenschaften von Makrocyclen aus Resorcinen sowie von entsprechenden Derivaten und Wirt‐Gast‐Komplexen
Authors: Schneider Ulrich , Schneider Hans‐Jörg 
Published: July 2007

Synthesis and Properties of Macrocycles from Resorcinol, Corresponding Derivatives and Host‐Guest ComplexesStructural variations of the metacyclophanes obtained from the condensation of resorcinol with aldehydes RCHO are described, mostly based on the stereoisomer with all R in cis configuration. The basic tetraphenolate (with R = CH3, 1a) shows a cone‐conformation as evident e.g. from vicinal 13C–C–C–1H coupling constants. Substituents R′ in the 2‐position of the phenyl rings at the upper rim of the macro‐cycle are either introduced with the resorcinol derivative used (R′ = CH3, COOH), or by Mannich reactions after cyclization (R′ = CH2NR″2), which partially lead to intermediate oxacine formation. Acid‐base properties are evaluated with potentiometric and NMR‐shift titrations. Mannich products from amino acids such as proline, which are formed without racemization, show no pK differences for the groups at the four equivalent phenyl rings, but three distinct pK values for the deprotonation of OH, COOH, and +NH3 substituents; the pK of the latter is two units lower than in proline itself as it is involved in hydrogen bridging. Complexation constants K of such derivatives with Fe3+, Cu2+, and Zn2+ show the expected increase with metal ion acidity; they are increased by a power of 5 in comparison to proline. Complexation constants and complexation‐induced NMR shifts (CIS values) are determined for 51 complexes, with positively charged organic guest molecules for the basic tetraphenolate skeleton as well as for the aminomethylation derivatives. A temperature dependence study shows that the corresponding equilibrium is driven by ΔH with negligible ΔS contributions. No chiral discrimation is observed upon complexation of e.g. carnitine with the optically active amino acid derivatives. This is in line with CIS and K values obtained with several complexes showing an orientation of the NR″2 groups away from the cavity. The COOH substituents R′ form strong hydrogen bonds with the adjacent phenolic groups, leading to alternating pseudo‐eq and ‐ax positions of the phenyl rings. Their interconversion barrier, determined by NMR spectroscopy, is 72 kJ mol‐1; they bind mono‐ and bis‐ammonium ions as function of distance matching. The presence of lipophilic substituents (R = phenyl, benzyl, biphenyl, n‐hexyl, n‐undecyl) at the bottom of the macrocycle furnishes a second binding center which allows to complex e.g. diethyl ether in water. Coordination of zinc to the proline derivative still allows co‐complexation of choline acetate, the hydrolysis of which is not inhibited anymore as it is by the zinc‐free macrocycle.
Coordination Polymers, IX[1] Synthesis and Crystal Structure of a 1D‐Sodium Coordination Polymer: [NaL4(PMDETA)]∞
Authors: Saalfrank Rolf W. , Struck Oliver , Davidson Matthew G. , Snaith Ronald 
Published: July 2007

AbstractReaction of sodium hydride with the tridentate tetrazole ligand 10 (HL4) and pentamethyldiethylenetriamine (PMDETA) in toluene yields by self‐assembly in the solid‐state the well‐ordered 1D‐coordination polymer [NaL4(PMDETA)]∞, (11). The structure of 11 was established by single‐crystal X‐ray diffraction. The generation of the 1D‐polymer 11 is understandable if intermediate formation of coordinatively unsaturated, neutral sodium building blocks [NaL4(PMDETA)] (12) is assumed. Such a self‐complementary monomer 12 acts in a monodentate fashion via its CN group, leading to linkage of monomers and to coordinative saturation at the sodium centre of 12. The sodium ions of the resulting polymeric chains of 11 are coordinated in a distorted octahedral manner. These results indicate that sodium derivatives of CN‐containing ligands may be tuned as to their dimensionality, especially so since Na+ can cope with coordination numbers of 4, 5, or 6, such tuning could be probed initially by provision of further available functionalities within the anionic ligand and/or by provision of Lewis base donors of varying denticity.
Face‐Selective and endo‐Selective Cycloadditions with Enantiomerically Pure Cyclopentadienes
Authors: Beckmann Marion , Meyer Thorsten , Schulz Frauke , Winterfeldt Ekkehard 
Published: July 2007

AbstractA general synthetic route to the enantiopure bicyclic cyclopentadienes (S)‐3 and (R)‐3 of the hydrindane series, starting from the Hajos‐Wiechert ketone 4 or its enantiomer is described. Reasons for the excellent face and endo selectivity of cycloadditions and the resulting consequences for chiral recognition are discussed.
Stereoselective Synthesis of Alcohols, XLVII[1] Application of Chiral Z‐Pentenylboronates to the Synthesis of Erythronolide Building Blocks
Authors: Hoffmann Reinhard W. , Stürmer Rainer 
Published: July 2007

AbstractThe chiral pentenylboronate 3 was the key reagent in the stereoselective construction of two erythronolide building blocks 6 and 7. Addition of 3 to achiral aldehydes furnished homoallylic alcohols 21 and 26 with >98% e.e. Addition of 3 to chiral aldehydes 8 or 11 generated homoallylic alcohols with >95% d.e. In the mismatched case of addition to the aldehyde 29 diastereoselectivity reached merely 80%.
Heterogene Gasphasen‐Eliminierungen mit dem System Magnesiumoxid/Kalium
Authors: Maier Günther , Weber Claudia 
Published: July 2007

Heterogeneous Gasphase Eliminations with the System Magnesium Oxide/PotassiumAfter evaporation of potassium and condensation on a magnesium oxide surface a highly reactive blue reagent is formed which is active in dehydrogenation reactions. 1,4‐Cyclo‐hexadiene (1) and 1,3‐cyclohexadiene (2) can effectively be converted into benzene at room temperature while dehydrogenation of cyclohexene 3 needs temperatures higher than 200°C. The reaction mechanism is discussed. Debrominations with MgO/K can likewise be carried out under rather mild conditions.
Reaktionen von R2AlAlR2 (R  CH(SiMe3)2) mit Trimethylsilylazid — Insertion in die AlAl‐Bindung und Abbau zum trimeren Dialkylaluminiumazid
Authors: Uhl Werner , Gerding Rolf , Pohl Siegfried , Saak Wolfgang 
Published: July 2007

AbstractReactions of R2AlAlR2 (R  CH(SiMe3)2) with Trimethylsilyl Azide — Insertion into the AlAl Bond and Formation of a Trimeric Dialkylaluminium AzideTetrakis[bis(trimethylsilyl)methyl]dialuminium(4) (1) reacts with trimethylsilyl azide under insertion of one nitrogen atom into the AlAl bond. As shown by NMR spectra and crystal structure the product contains three and four coordinated Al atoms due to the coordination of the α‐nitrogen atom of the azide group to one of the Al atoms. An electronically delocalized N3‐system is formed with a NN bond length of 132.0 pm and a bond order of 1.5 for both NN bonds. With an excess of trimethylsilyl azide further reaction is observed only under mild irradiation conditions with an exchange of the azide group between Si and Al and formation of Me6Si2 and the dialkylaluminium azide 3, which is better synthesized by the reaction of Me3SiN3 with ClAl[CH(SiMe3)2]2. The sterically highly shielded aluminium azide 3 is a trimer in the solid state showing a non‐planar 12‐membered Al3N9 heterocycle with short NN bonds (114 pm).
Darstellung und Charakterisierung der Tetrahedrane [CpM(CO)2]3P (M = Mo, W) sowie der Derivate [CpMo(CO)2]3P‐Mo(CO)5 und [CpW(CO)2]3P–W(CO)5
Authors: Kilthau Thomas , Nuber Bernd , Ziegler Manfred L. 
Published: July 2007

Synthesis and Characterization of the Tetrahedranes [CpM(CO)2]3P (M = Mo, W) and Their Derivatives [CpMo(CO)2]3P–Mo(CO)5 and [CpW(CO)2]3P–W(CO)5The reaction of Na[CpM(CO)3] (M = Mo, W) with PCl3 in diglyme yields the cluster compounds [CpMo(CO)2]3P–Mo(CO)5 (2a) and [CpW(CO)2]3P–W(CO)5 (2b) in good yields as well as the tetrahedranes [CpMo(CO)2]3P (3a) and [CpW(CO)2]3P (3b) as side products. Compounds 3a, b are obtained independently by the reaction of 2a, b with PPh3. The clusters 2a, b and 3a, b were characterized spectroscopically (IR, NMR, MS), and X‐ray structure determinations were carried out on 2a, b.
Pn‐Liganden mit maximaler Elektronendonorfähigkeit, 7. Dreikomponentenreaktion von P4‐Phosphor mit [CpxRh(CO)2] in Gegenwart von [Cr(CO)5THF] oder [CpMn(CO)2THF]. – Eine Methode zum Studium des Transformationsweges vom P4‐Tetraeder zum planaren cyclo‐P4‐Liganden
Authors: Scheer Manfred , Troitzsch Christa , Hilfert Liane , Dargatz Manfred , Kleinpeter Erich , Jones Peter G. , Sieler Joachim 
Published: July 2007

Pn Ligands with Maximum Electron‐Donor Capacity, 7. – Three‐Component Reaction of P4‐Phosphorus with [CpxRh(CO)2] in the Presence of [Cr(CO)5THF] or [CpMn(CO)2THF]. – A Method of Studying the Pathway from Tetrahedral P4 to the Planar cyclo‐P4 LigandHerrn Professor Gerhard Fritz zum 75. Geburtstag gewidmet.
The reaction of P4 with [CpxRh(CO)2] (Cpx = Cp′, Cp′′; Cp′ = η5‐C5H4tBu, Cp′′ = η5‐C5H3tBu2‐1,3) in the presence of [Cr(CO)5THF] leads to [CpxRh(CO)(η1:1‐P4){Cr(CO)5}4] (1a, b), [Cp′′Rh(η4‐P4){Cr(CO)5}3] (2b), and [Cp′Rh(η4‐P4){Cr‐(CO)5}4] (3a). In the corresponding reaction with [CpMn‐(CO)2THF] no P4 takes part, and [(Cp′′RhCO)(CpMnCO)(μ‐CO)2] (4) is formed. An X‐ray structure determination of [CpxRh(CO)(η1:1‐P4){Cr(CO)5}4] (1) and [Cp′Rh(η4‐P4)‐{Cr(CO)5}4] (3a) indicates a stepwise (PP) bond cleavage as the transformation pathway from the P4 tetrahedron to the cyclo‐P4 ligand by passing a bicyclotetraphosphane. In the cyclo‐P4 ligand complex 3a all P atoms are able to coordinate to [Cr(CO)5] groups. However, in [Cp′′Rh(η4‐P4){Cr(CO)5}3] (2b) the additional tBu group at the Cpx ligand sterically influences the coordination behavior of the P atoms, and only three of them are able to coordinate to [Cr(CO)5] units. In these syntheses the [Cr(CO)5] moieties promote the reaction and stabilise intermediates along the reaction pathway. Variable‐temperature 31P{1H}‐NMR measurements indicate for 2b the freezing of the Cp′′ rotation at low temperature and reveals a ΔG (at the coalescence temperature) of 36 kJ mol−1. Surprisingly, in [(Cp′′RhCO)(CpMnCO)(μ‐CO)2]‐(Rh‐Mn) (4) the Cpx ligands are cis‐oriented whereas in [(Cp*RhCO)(CpMnCO)(μ‐CO)2](Rh‐Mn) a trans arrangement is observed. This indicates the unusual behavior of the Cp′′ ligand as a “rod” and not as an “enlarged disk” like Cp* in the crystal lattice of these compounds.
Darstellung von phosphor‐ und fluorhaltigen Calix[4]aren‐Derivaten. Konformationsanalyse, Trennung der Konformere und Röntgenstrukturanalyse an einem Konuskonformer
Authors: Neda Ion , Plinta Hans‐J. , Sonnenburg Ralf , Fischer Axel , Jones Peter G. , Schmutzler Reinhard 
Published: July 2007

Preparation of Phosphorus— and Fluorine‐Containing Calix[4]arene Derivatives. Conformational Analysis, Separation of the Conformers, and X‐Ray Crystal Structure Analysis of a Cone ConformerHerrn Professor Helmut Werner zum 60. Geburtstag gewidmet.
The Calix[4]arene 1 reacts with hexamethyldisilazane or (diethylamino)trimethylsilane to form the bis‐trimethylsilyl‐ated derivative 2. Treatment of 2 with PF2C1 gives the mono‐and bis‐difluorophosphites 3 and 4, which react with elimination of Me3SiF or PF3 to yield the monofluorophosphite derivative 5. All four OH hydrogen atoms in 1 are replaced by lithium on reaction with nBuLi with formation of the tetrali‐thiated product 6. This has been allowed to react with the Pchlorophosphorinanones 7–9. From 7 the cone conformer 10a is formed, whereas in the case of 8 and 9 a mixture of all four possible conformars 11a‐d and 12a‐d is obtained. The pure conformers 12a‐d are isolated. By refluxing the cone conformer 12a in tetrachloroethane a conformational conversion is effected. In order to evaluate its coordinating ability, 12a was allowed to react with dichloro(cycloocta‐1, 5‐diene)platinum(II) to form the trans‐disubstituted complex 13. In the case of 12a (acetonitrile solvate) a single‐crystal X‐ray structure analysis has been conducted. The molecule displays a cone conformation, whereby two of the opposing phenyl rings are approximately parallel and the other two approximately perpendicular to each other.
Synthese kationischer η2‐Phosphinocarben‐Komplexe des Molybdäns und Wolframs
Authors: Kreißl Fritz R. , Ostermeierx Josef , Ogric Cynthia 
Published: July 2007

Synthesis of Cationic η2‐Phosphinocarbene Complexes of Molybdenum and TungstenHerrn Professor Hubert Schmidbaur zum 60. Geburtstag gewidmet.
The reaction of chlordimethylphosphane or chlordiphenyl‐phosphane and sodium tetraphenylborate with dicarbonyl(η5‐cyclopentadienyl)carbyne complexes of molybdenum and tungsten enables the direct conversion of a MCR group into a MC(R)PR2 unit providing dicarbonyl substituted η2‐phosphinocarbene complexes in high yields. In the absence of Na[BPh4] a base induced carbonyl carbene coupling reaction affords η3‐phosphinoketene complexes.
Fe(NCMe)‐Komplexe von chiralen Tripodliganden mit drei verschiedenen Donorgruppen: Dynamik und Struktur
Authors: Heidel Horst , Scherer Johannes , Asam Alexander , Huttner Gottfried , Walter Olaf , Zsolnai Laszlo 
Published: July 2007

Fe(NCMe) Complexes of Chiral Tripod Ligands Bearing three Different Donor Groups: Dynamics and StructureChiral tripod ligands [tripod = CH3C(CH2PR2)(CH2PR′2)(CH2‐PR′′2), 1a–d] with three different donor groups react with Fe(NCMe)6(BF4)2 to yield the complexes tripodFe(NCMe)3(BF4)2 (2a–d). These complexes show an idealized octahedral coordination based on a facial coordination of the tripod ligand. The asymmetry of the chiral tripod ligands a–d induces a differentiation of the remaining coordination sites at iron. The structure and the dynamic behaviour of the compounds 2a, b is elucidated by X‐ray structural analyses and 2D‐NMR techniques.
Transition‐Metal Complexes with the Novel Scorpionate Ligand Dihydrobis‐(tetrazolyl)borate: Synthesis and Characterization of Infinite Two‐Dimensional Metal‐Ligand Frameworks and One‐Dimensional Water Substructures
Authors: Janiak Christoph , Scharmann Tobias G. , Brzezinka Klaus‐Werner , Reich Peter 
Published: July 2007

AbstractDihydrobis(tetrazolyl)borate metal compounds of the composition [M(L)2{μ‐H2B(CHN4)2}2]n for M = Mn, Fe, Co, Zn, Cd with L = H2O and for M = Cu with L = NH3 are obtained from metal salts and K[H2B(CHN4)2]. Single‐crystal X‐ray studies reveal the formation of two‐dimensional rhombic grid sheets through the bridging action of the bis(tetrazolyl)borate ligands. Each metal atom is octahedrally coordinated with two trans L ligands and four H2B(CHN4) nitrogen donors. Two additional, hydrogen‐bonded water molecules occupy the rhombic openings in the compounds with M = Mn, Fe, Co, Zn, and Cd. The water of crystallization is held in place through hydrogen bonding from the water ligands and to the nitrogen atoms to give a substructure of parallel kinked water chains. Temperature‐variable magnetic measurements show a Curie‐Weiss behavior for the paramagnetic complexes with M = Mn, Fe, Co, and Cu.