bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses and Reactivity of Aminobis(diorganylamino)phosphanes
Authors: Schick Gerold , Loew Armin , Nieger Martin , Airola Karri , Niecke Edgar 
Published: July 2007

AbstractAminobis(diorganylamino)phosphanes (R2N)2PNH2 (R = iPr, c‐Hex, Ph) (2a–c), were obtained by treatment of the corresponding chlorobis(diorganylamino)phosphanes 1a–c with lithium amide in liquid ammonia. The transition metal phosphane complex (R2N)2(H2N)PNi(CO)3 (3) was prepared by reaction of 2a with tetracarbonylnickel. N‐Complexation of 2a with trimethylalane affords the iminophosphorane‐alane adduct (R2N)2HP=N(H)AlMe3 (4) by 1,2‐H shift from the nitrogen to the phosphorus atom. The corresponding reaction with aluminium trichloride leads to the formation of the salt [(R2N)2HP=N(H)]2AlC12+[AlC14]− (5), in which two iminophosphorane moieties are linked by an AlCl2 bridge. Lithiation of 2a and subsequent reaction with titanocene dichloride result in nucleophilic replacement of one chlorine atom to give the phosphanylamido‐substituted titanocene compound (R2N)2P–N(H)Ti(Cl)Cp2 (6a), which rearranges to its P‐hydroiminophosphorane tautomer (R2N)2P(H)=NTi(Cl)Cp2 (6b) on gentle heating. No isomerisation was observed in the case of N‐borylated aminophosphane (R2N)2P–NH–(9‐BBN) (7), obtained by reaction of lithiated 2a with B‐Cl‐9‐BBN. The X‐ray structure analyses of compounds 2b, c, 3, 4, 5, and 6a are discussed.
Second‐Sphere Coordination
Authors: Raymo Françisco M. , Stoddart J. Fraser 
Published: July 2007

AbstractThe design and synthesis of artifical receptors, able to recognize and bind transition metal complexes, is an area of growing interest in supramolecular chemistry. Macrocyclic hosts such as crown ethers, cyclodextrins, and cyclophanes have been employed to generate second‐sphere adducts with numerous transition metal complexes as a result of nonconvalent bonding interactions, such as hydrogen bonding, π‐π stacking, and hydrophobic interactions. The effect of second‐sphere coordination on the chemical, electrochemical, and photochemical properties of the adducts, as well as on their geometries in solution and in the solid state, has been investigated; these investigations have demonstrated the potential of second‐sphere coordination in modulating the behavior of transition metal complexes by designed external intervention.
Synthesis, Molecular Structure and Reactions of Stable Square‐Planar 16‐Electron Ruthenium(0) Complexes: trans‐[RuCl(NO)(PR3)2]☆
Authors: Flügel Ruth , Windmüller Bettina , Gevert Olaf , Werner Helmut 
Published: July 2007

AbstractThe reduction of [RuCl3(NO)(PPh3)2] (1) with Zn/Cu generates [RuCl(NO)(PPh3)2] that by ligand exchange with PR3 (R3  iPr3, iPr2Ph) affords the stable 16‐electron ruthenium (0) complexes trans‐[RuCl(NO)(PR3)2] (2, 3). The X‐ray structural analysis of 2 confirmed the square‐planar geometry around the metal center. HCl oxidatively adds to 2 and 3 to give the octahedral ruthenium(II) compounds [RuHCl2(NO)(PR3)2] (4, 5). On treatment of 2 and 3 with CO, TCNE, CH2 (generated from CH2N2) and O2, five‐coordinate 1:1 adducts [RuCl(NO)(L)(PR3)2] (6–12) are formed. The dioxygen complexes 11 and 12 react with SO2 to afford the sulfatoruthenium(II) derivatives [RuCl(NO){η2(O,O)‐O2SO2}(PR3)2] (13, 14). Compound 13 (R3  PiPr3) has been characterized by X‐ray structural analysis.
Cationic Iron Aminocarbene Complexes as Dienophiles in Diels‐Alder Reaction with Cyclopentadiene
Authors: Rück‐Braun Karola , Köuhn Jörg 
Published: July 2007

AbstractThe cationic iron (alkynyl)aminocarbene complexes [Cp(CO)2Fe(C(NHR)CCSiMe3][PF6], (R  C6H5,p‐CH3C6H4)1derived from aromatic amines smoothly react with cyclopentadiene in dichloromethane to yield the cycloadducts2. No reaction was observed for complexes derived from sterically demanding aliphatic amines, likeL‐alaninetert‐butyl ester. For comparison, the alkynyl‐substituted acyl iron compounds Cp(CO)2Fe(CO)CC̊ (R  SiMe3, C6H5)3were investigated, requiring TiCl4catalysis to undergo the cycloaddition reaction. The structures of the cycloadducts4were determined by X‐ray crystallography.
Zweikernige Tripod‐Cobalt‐Komplexe mit verbrückenden 1,4,5,8‐Tetraoxonaphthalin und 1,4,9,10‐Tetraoxoanthracen‐Liganden: Strukturen, spektroskopische, magnetische und elektrochemische Eigenschaften
Authors: Heinze Katja , Mann Susanne , Huttner Gottfried , Zsolnai Laszlo 
Published: July 2007

Dinuclear Tripod Cobalt Complexes with Bridging 1,4,5,8‐Tetraoxonaphthalene and 1,4,9,10‐Tetraoxoanthracene Ligands: Structures, Spectroscopic, Magnetic, and Electrochemical PropertiesThe syntheses, structures, optical, magnetic, and redox properties of dinuclear tripodcobalt(II) complexes [tripod = CH3C(CH2PPh2)3] with briding 1,4,5,8‐tetraoxonaphthalene 12‐ and 1,4,9,10‐tetraoxoanthracene 22‐ are described. UV/Vis/NIR spectroscopy indicates interaction between the ligand and the metal orbitals. The magnetic interactions involving the two cobalt(II) centers and the bridging ligand are characterized by EPR spectroscopy and magnetic measurements and are analyzed in terms of qualitative Molecular Orbital calculations. The redox chemistry of these complexes is investigated by cyclic voltammetry and interpreted as metal‐based oxidations and ligand‐based reductions.
The Thermally Induced Solid‐State Polymerization Reaction in Halogenoacetates
Authors: Epple Matthias , Kirschnick Holger 
Published: July 2007

AbstractNine salts of halogenoacetic acids MOOC–CH2X were prepared and characterized by their thermochemical reactivity. It was found that in seven cases elimination of MX led to polymerization of the organic part of the molecule. The resulting polyester, polyglycolide, could be isolated easily by washing the reaction product with water. It has a distinct porous morphology. The reaction takes place at moderate temperatures (100200°C).
The Crystal Structure of Bi8(AlCl4)2 and the Crystal Structure, Conductivity, and Theoretical Band Structure of Bi6Cl7 and Related Subvalent Bismuth Halides
Authors: Beck Johannes , Brendel Claus J. , Bengtsson‐Kloo Lars , Krebs Bernt , Mummert Marita , Stankowski Alexander , Ulvenlund Stefen 
Published: July 2007

AbstractThe methods of preparation for Bi8(AlCl4)2 and Bi6Cl7 have been improved and the single crystal structures for these cluster compounds re‐investigated and re‐interpreted. In addition, conductivity measurements and band structure calculations using the tight‐binding approximation have been performed on Bi6Cl7 and related subvalent bismuth halides. – Bi8(AlCl4)2 consists of isolated AlCl4‐ anions and rather undistored square‐antiprismatic Bi82+ clusters with an average Bi–Bi distance of 3.10 Å. Relatively short intercluster Bi–Bi contacts of 3.90 Å suggest weak bonding interactions between the Bi82+ units. In contrast, the structure determination of Bi6Cl7 implies that this structure should be regarded as being composed of discrete Bi95+ clusters and a polymeric BiIII–Cl anionic lattice including infinite, distorted α1[Bi2Cl24+] chains. According to the experimental and theoretical results, the Bi6X7 (X = Cl, Br) family of subvalent bismuth halide compounds are anisotropic semiconductors along the crystallographic c axis. The conductivity is mediated by the onedimensional α1[Bi2Cl24+] chains. These are interconnected with the Bi95+ clusters, which are acting as electron reservoirs. The related BiX (X = Br, I) family of subvalent bismuth halides are shown to be anisotropic semiconductors in the crystallographic b direction.
Zur Transformation des P4‐Tetraeders durch Ni‐Komplexe
Authors: Scheer Manfred , Becker Uta 
Published: July 2007

The Transformation Pathway of the P4Tetrahedron by Ni ComplexesThe thermal reaction of [Cp*NiCO]2with white phosphorus in the presence of [Cr(CO)5(thf)] at 70°C produces the bentcyclo‐P4ligand complex4and the Ni2P4prismane5. However under photochemical conditions additional products such ascyclo‐P3complexes6and the Ni2P2tetrahedrane7are also formed.4and5were characterized by NMR, IR, and mass spectroscopy as well as by X‐ray structure analysis. The structures of these products and the experimentals verification of the conversion of4into5or into6and7as well as the cubane analog12gives evidence for a transformation pathway starting from P4tetrahedron via a possible bicyclotetraphosphane intermediate to give the bent P4complex4. From4several pathways are possible; the main route is to form the Ni2P4prismane5. Photochemically a P3/P1fragmentation also occurs, albeit in low yield, to give5and6.
The Chemistry of 1,3,5‐Triazacyclohexane Complexes, 4. Strained 1,3,5‐Triazacyclohexane Complexes of Copper(I) and Copper(II)
Authors: Dag Köhn Randolf , Seifert Guido , Kociok‐Köhn Gabriele 
Published: July 2007

AbstractIn this paper we report on the synthesis and the crystallographic characterization of η3‐1,3,5‐triazacyclohexane (R3TAC) complexes of copper(I) and copper(II). The complexes [{Me3TAC)CuCl2}2] (1), [(iPr3TAC)CuCl2] (2), [{(PhCH2)3TAC}Cu(PPh3)](BF4) (3), and [(iPr3TAC)Cu(PPh3)]‐(BF4) (4) were characterized by X‐ray crystallography. The highly strained and bent Cu–N bonds are longer than in the corresponding complexes of other amine ligands. One methylene carbon atom of the ring comes close to the copper atom (2.55–2.65 Å). However, investigation of the ring deuterated complexes by IR and X‐ray crystallography ([D6]2) showed no clear evidence for attractive C–H–Cu interactions.
Synthese, Eigenschaften und Kristallstrukturen der Titan(III)‐Amido‐Komplexe Ti[N(SiMe3)2]3, [TiCl2{N(SiMe3)2}(THF)2] und [Na(12‐Krone‐4)2][TiCl2{N(SiMe3)2}2]
Authors: Putzer Markus A. , Magull Jörg , Goesmann Helmut , Neumüller Bernhard , Dehnicke Kurt 
Published: July 2007

Syntheses, Properties, and Crystal Structures of the Titanium(III) Amido Complexes Ti[N(SiMe3)2]3, [TiCl2{N(SiMe3)2}(THF)2], and [Na(12‐Crown‐4)2][TiCl2{N(SiMe3)2}2]TiCl3(THF)3 reacts with NaN(SiMe3)2 to furnish [TiCl2{N(SiMe3)2}(THF)2] (1), whereas in the presence of 12‐crown‐4 the ionic amido complex [Na(12‐crown‐4)2][TiCl2{N(SiMe3)2}2] (5) is obtained besides [Na(12‐crown‐4)2][TiCl4(THF)] (4). On the other hand, the titanium(III) amido complex Ti[N(SiMe3)2]3 (2), the crystal structure of which was solved, reacts with NaN(SiMe3)2 in the presence of 12‐crown‐4 with deprotonation of one of the methyl groups to give the carbometalated complex [Na(12‐crown‐4)2][Ti{N(SiMe3)2}2{N(SiMe 3CH2)}] (3).
Steroids as Chiral Ligands: Different Molecular and Crystal Structures of Copper(II) Complexes of Mono‐ and Dideprotonated 16β‐Salicylideneimino‐17β‐hydroxy‐3‐methoxyestra‐1,3,5(10)‐triene
Authors: Krieg Reimar , Dubs Manuela , Görls Helmar , Schönecker Bruno 
Published: July 2007

AbstractThe steroidal 16β‐salicylideneimino‐17β‐hydroxy compound 1, synthesized from the corresponding 16β, 17β‐amino alcohol, served as a new tridentate chiral ligand for Cu2+‐complexation. The X‐ray data for 1 and for two dimeric copper complexes 2 and 3 are presented and discussed. Using copper(II) acetate for complexation, dideprotonation of 1 is observed. The neutral complex 2 obtained is characterized by a central planar four‐membered copper—oxygen ring. The cycloaliphatic 17β‐oxygen anions are bridging atoms; the copper ions are tetracoordinated. Reaction of 1 with copper(II) perchlorate gave only monodeprotonation of the phenolic groups. These oxygen anions are now the bridging atoms; furthermore the two copper ions are bridged by a perchlorate anion. Thus the central four‐membered ring is folded (22°), and the copper ions are hexacoordinated (binding of a molecule of water). The crystal lattices of 2 and 3 are also quite different.
Ethene Polymerization Activity and Coordination Gap Aperture in non‐ansa Alkyl‐substituted Cyclopentadienyl‐ and Phospholyl‐zirconium/MAO Catalysts
Authors: Janiak Christoph , Lange Katharina C. H. , Versteeg Uwe , Lentz Dieter , Budzelaar Peter H. M. 
Published: July 2007

AbstractThe ethene polymerization activities of a series of Cp'(C5H5)ZrCl2 and Cp'2ZrCl2 pre‐catalysts (Cp' = C5HMe4, C4Me4P, C5Me5, C5H4tBu, C5H3‐1,3‐tBu2, C5H2‐1,2,4‐tBu3) together with (C5H5)2ZrCl2 have been correlated with the coordination gap aperture. In the case of the mixed substituted C5R5‐nR'n ligands, the coordination gap aperture has been determined with the help of the cyclopentadienyl cone angle and the bending angle at zirconium. A hindered rotatability of the tert‐butyl substituted systems has been evaluated by molecular modeling calculations and was included in the gap aperture estimation. Deviations from the activity—gap aperture correlation in the case of the phospholyl (C4Me4P) systems could be accounted for in terms of adduct formation between aluminum species and the phosphorus donors. These Lewis acid/base adducts form in an equilibrium reaction at high Al/Zr ratios, as shown by 31P NMR. Ab initio calculations on model L2TiMe+ complexes (L = C5H5, C5H4N and C5H4P) for the insertion of ethene in the TiMe bond suggest a high electronic similarity for phospholyl and cyclopentadienyl. The 91Zr‐NMR data (chemical shift and line width) for the above zirconocene series are reported. The 91Zr chemical shift values increase with a good linear correlation to the number of methyl or tert‐butyl groups, which is traced to the additive electron donating effect of the alkyl groups. The hyperconjugative donor effect of a tert‐butyl group is found here to be 1.25 times that of a methyl group. The X‐ray structure of (C5H3‐1,3‐tBu2)(C5H5)ZrCl2 has been determined (monoclinic, P21/n, a = 6.631(3), b = 18.843(9), c = 15.265(5) Å, β = 91.3°, Z = 4).
Selenocyanato Derivatives of Hydro‐closo‐borates: Syntheses and Crystal Structures of (PPh4)2[SeCN)BnHn–1] (n = 6, 10, 12)
Authors: Nachtigal Christiane , Steuer Boris , Preetz Wilhelm 
Published: July 2007

AbstractThe hydro‐closo‐borates [BnHn]2– (n = 6, 10, 12) react with (SeCN)2 in organic media to yield derivatives with one SeCN group bound via Se to the Bn polyhedra. This was verified by single‐crystal X‐ray structural analysis of the isotypical (P1¯) tetraphenylphosphonium salts (PPh4)2[(SeCN)B6H5] (1), (PPh4)2[1‐(SeCN)B10H9] (2) and (PPh4)2[(SeCN)B12H11] (3) The 11B‐NMR spectra reveal the features of monosubstituted hydro‐closo‐borates. The 77Se‐NMR resonances are observed in the downfield region between δ = −22.6 and −78.8 characteristic of Se‐bonded SeCN groups.
Layered Ternary and Quaternary Metal Chalcogenides
Authors: Pell Michael A. , Ibers James A. 
Published: July 2007

AbstractThe syntheses, crystal structures, and physical properties of some recently discovered layered ternary and quaternary chalcogenides are reviewed. One component of these systems is an alkali metal or thallium; another is a d‐, f‐, or p‐ block metal.
Synthesis of Functionalized Carbamates through a Palladium‐Catalyzed Reductive Carbonylation of Substituted Nitrobenzenes
Authors: Wehman Petra , Borst Leo , Kamer Paul C. J. , Leeuwen Piet W. N. M. Van 
Published: July 2007

AbstractThe palladium‐catalyzed reductive carbonylation of ortho and para‐substituted nitrobenzenes has proven to be an attractive route for the synthesis of functionalized carbamates. For the Pd(1, 10‐phenanthroline)2(triflate)2 catalyst system, the scope of the reaction has been studied. Substrates with electron‐donating substituents at the para position were found to decrease the catalytic activity, most probably as a result of their relatively low oxidizing capacity. the selectivity towards the desired carbamate, however, was increased for these substrates. Under the influence of electron‐withdrawing substituents the azoxybenzene and azobenzene derivatives became important side products. Introduction of large steric hindrance at the ortho position of the nitro substrates gave rise to an interesting side reaction, viz. methoxylation of the aromatic ring. The methoxylation reaction appeared to occur on an intermediate species in the catalytic cycle. Several functionalities have shown to be resistant to the reaction conditions required for the conversion ot the nitro group. Especially with 4‐nitrobenzoic acid, an extremely high activity and selectivity was found, thus yielding a very convenient synthesis for N‐protected amines containing carboxylic acid function.
Triphenylphosphonio‐Substituted 1,2,3,4‐Triazaphospholes and 1,2,4‐Diazaphospholes
Authors: Schrödel Hans‐Peter , Schmidpeter Alfred 
Published: July 2007

AbstractSeveral products resulting from the condensation of the bis‐(trimethylsilyl)ylide 1 with PCl3 serve as synthetic equivalents of a phosphoniophosphaethyne. Cycloaddition reactions with azides lead to phosphonio‐1,2,3,4‐triazaphosphole cations 5, 7 and to the zwitterionic phosphonio‐1,2,3,4‐triazaphospholide 6. The latter readily undergoes a cycloreversion yielding a phosphoranediyl diazomethane 12 as intermediate. Its cycloaddition affords the diphosphonio‐1,2,4‐diazaphosholide chloride 9a as the final product. 9a is a remarkably stable and unreactive derivative of the two‐coordinate phosphorus. By HCL it is protonated at a nitrogen atom to give dication without any tendency to associate with the chloride counterions.
Bildung und Charakterisierung des Dinatrium‐tetraphosphendiids (tBu3Si)NaP–PP–PNa(SitBu3) und seines Dimeren
Authors: Wiberg Nils , Wörner Angelika , Karaghiosoff Konstantin , Fenske Dieter 
Published: July 2007

AbstractReaction of P4 in THF or DME with 2 R*Na (R* = SitBu3) at –78°C leads quantitatively to deep red THF or DME adducts of R*NaP–PP–PNaR* (3). According to 31P NMR, the P4 skeleton 3 is cis‐configurated. On the other hand, reaction of P4 in TBME with 2 R*Na at ‐78°C leads quantitatively to (R*NaP)4 (4), a [2+2] cycloadduct of 3, the Na4P8 skeleton of which according to X‐ray structure analysis forms a double cube with four P atoms in the second layer and two P and two Na atoms in alternating positions in the first and in the third layer (the Na atoms are coordinated with donors). By resolving the THF adduct 3 in TBME (the TBME adduct of 4 in THF) the compound 4 (the compound 3) is rapidly formed under reversal of the P–PP–P configuration by way of [2+2] cycloaddition (by way of [2+2] cycloreversion). 3 and 4 are sensitive to oxidation and to protolysis. With TCNE, 3 is oxidized to R*2P4 (bicyclic P4 skeleton), with CF3SO3H, 3 may be transformed into R*3P5Na2 X 4 THF or in (R*P3)3 and R*PH2.
1,2‐FDTA: A Ferrocene‐Based Redox‐Active EDTA Analogue with a High Ca2+/Mg2+and Ca2+/Sr2+ Selectivity in Aqueous Solution
Authors: Plenio Herbert , Burth Dirk , Vogler Raphael 
Published: July 2007

Abstract1, 2‐Ferrocenemethylenediyldiamino tetraacetate (1,2‐FDTA) is a redox‐active relative of EDTA and was synthesized in the reaction of 1,2‐bis(chloromethyl)ferrocene with iminodiacetate methyl ester followed by cleavage of the ester with methanolic KOH. Potentiometric determination of the stability constants of the complexes of 1,2‐FDTA with the alkaline earth metal ions showed this ligand to display a higher Ca2+/Mg2+ and Ca2+/Sr2+ selectivity (Ca2+ log K = 6.56, Mg2+ log K = 4.65, Sr2+ log K = 3.32) than EDTA itself. The redox potential of 1,2‐FDTA‐Ca2+ determined in aqueous solution by cyclic voltammetry was found to be anodically shifted by +50 mV with respect to that of the calcium free complex. Consequently the redox‐inactive calcium can be determined electrochemically in aqueous solution with a high selectivity with respect to the other alkaline earth metal ions.
Gold(1) Complexes of Ketiminophosphanes and ‐phosphane Sulfides
Authors: Schneider Wolfgang , Bauer Andreas , Schier Annette , Schmidbaur Hubert 
Published: July 2007

AbstractThe reactions of chloro(dimethyl sulfide)gold(I) with equivalent quantities of the ketiminophosphane diphenyl(diphenylmethyleneamino)phosphane (1a) or its sulfide (1aS) lead to high yields of stable, crystalline 1 : 1 complexes with AuCl units attached to the phosphorus and sulfur atom, respectively. Tris(diphenylmethyleneamino)phosphane (1c) gives the related complex (Ph2CN)3PAuCl with the gold atom also selectively P‐bound. Bis(diphenylmethyleneamino)phenyl‐phosphane (1b) could not be used because of its limited stability. Single‐crystal X‐ray diffraction studies have shown that there is no auxiliary coordination of the metal center by the imino functions of the ligands. The geometry of the P/SAuCl moieties deviates only very slightly from linearity. The angle at the sulfur atom in (Ph2CN)Ph2PSAuCl is very small [94.30(3)°], but despite of the resulting rather open coordination there are no discernible intra‐ or intermolecular contacts in the lattice. Such contacts are also absent with (Ph2CN)Ph2PAuCl and (Ph2CN)3PAuCl owing to the bulk of the ligands. The 1 : 1 complexes do not react with an excess of (Me2S)AuCl. This finding, and the molecular structures of the 1 : 1 complexes, show very consistently that both phosphane and sulfide donors are far superior as ligands for gold(I) as compared to ketimine donor molecules.
Tetraphenyl rac‐3,3,7,7‐Tetramethyl‐trans‐5 palladatricyclo[4.1.0.02,4]‐heptane‐1,2,4,6‐tetracarboxylate: A New PTH Derivative and the First X‐ray Crystallographic Study of a Bis(acetone)palladium(II) Complex
Authors: Hashmi A. Stephen K. , Naumann Frank , Bats Jan W. 
Published: July 2007

AbstractThe title compound rac‐9 and its bis(acetone) complex rac‐10 were prepared, and the latter investigated by X‐ray structure analysis. rac‐10 proves that the coordination of the weak donor acetone, an easily substitutable ligand in PTHs and related compounds, is an essential point for dissolving these coordination polymers, and thus allowing catalysis reactions in such solvents. Furthermore rac‐10 shows only a small deviation from the square‐planar coordination expected for Pd11. This indicates that the strong deviation from planarity observed in complexes with more sterically demanding, bidentate ligands is caused by steric interactions with the substituents on the PTH, rather than by electronic effects.
Interactions in Molecular Crystals, 118. The Sodium(benzo‐15‐crown‐5) Salt of 2, 6‐Di(tert‐butyl)‐4‐methylphenol, a Sodium Phenolate with an Extremely Short Na+…O− Distance: Structure and Density Functional Calculations
Authors: Bock Hans , Dienelt Rüdiger , Näther Christian , Havlas Zdenek 
Published: July 2007

AbstractThe structure of crystals, isolated in low yield, from the attempted metallation of diphenylmethane in tetrahydrofuran solution containing benzo‐15‐crown‐5 at a sodium metal mirror is determined, surprisingly, to be the sodium (benzo‐15‐crown) salt of 2,6‐di(tert‐butyl)‐4‐methylphenol, an antioxidative stabilizer to prevent ether peroxide formation. The structure of the solvent‐shared contact ion pair (monoclinic P21/n, Z = 4, R1 = 0.06) proves a strong Na+…O− interaction at the extremely short distance of only 216 pm, a sixfold O‐coordination of the Na+ cation in a pentagonal pyramid, and a hemispherical distortion of the crown ether. Density functional calculations at the B3LYP/6‐31G* level, based on the structural data, reproduce, within a one‐dimensional hypersurface approach, the rather short Na+…O− distance, and predict Mulliken charges of +0.32 for Na′ and ‐0.71 for 0−, as well as a considerable polarization of the trialkyl phenolate anion.
Diastereoselective Synthesis and Molecular Structure of a Bicyclic and a Cage Phosphane
Authors: Bekiaris Georgios , Lork Enno , Offermann Werner , Röschenthaler Gerd‐Volker 
Published: July 2007

AbstractA two‐step formal insertion of 1,1,1,5,5,5‐hexafluoro‐ (2a) and 1,111‐trifluoropentane‐2,4‐dione (2b) into the P‐H bonds of phosphane gave the primary a‐hydroxyphosphanes 3 and 4, precursors for the resulting secondary phosphanes, 6,9‐dioxa‐2‐phosphabicyclo[3.3.l]nonane (6a) and 2,4,8‐trioxa‐6‐phosphaadamantane (7), both formed diastereospecifically. The molecular structures of 6a and 7 were established by single‐crystal X‐ray structure analysis which revealed two independent molecules for 6a in the unit cell possessing a chair‐boat conformation with a C‐P‐C angle of 95.4(2)°, and a characteristic heteroadamantane geometry for 7, with the corresponding angle being smaller by 4.9°.