bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Solution and Solid State Structure of L-Carnitine L-Tartrate
Authors: Schmidbaur Hubert , Schier Annette , Bayler Angela 
Published: February 2015

Abstract
L-Carnitine forms a salt-like 2:1 adduct with L-tartaric acid which crystallizes in the or-thorhombic space group P212121 with Z = 4 formula units in the unit cell. The lattice is composed of an L-tartrate dianion and two crystallographically independent L-carnitinium cations. The two cations show only very minor differences in their conformation. Anions and cations are arranged in separate stacks which are linked via hydrogen bonds. The tartrate anion and the carnitinium cations show standard geometries known from the structures of other salts of these ions, like the L-carnitine component of the R,L-carnitinium chloride or the dianion in alkali tartrates. The title compound has galenic advantages as an L-carnitine drug because of its non-hygroscopic properties. Aqueous solutions have been shown to contain solvated ionic components, i.e. L-tartrate and L-hydrogentartrate anions, L-tartaric acid (15:70:15) and carnitinium cations. The title compound can therefore be classified as a genuine L-carnitinium salt of L-tartaric acid.
Kristallstruktur von Cs2[B6H5(SCN)]/ Crystal Structure of Cs2[B6H5(SCN)]
Authors: Preetz W. , Zander S. , Bruhn C. 
Published: February 2015

Abstract
By reaction of [B6H6]2-with (SCN)2 in dichloromethane at -80 C° the thiocyanatohexaborate anion is formed and can be isolated by ion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The X-ray structure determination of Cs2[B6H5(SCN)] (orthorhombic, space group Pbca with a = 9.506(5), b = 10.644(5), c = 21.857(5) Å, Z = 8) reveals that the SCN substituent is bonded via the S atom with the B-S distance of 1.885(9) Å and the B-S-C angle of 99.8(5)°. The SCN group is nearly linear (179.9(9)°).
Synthesis and X-Ray Structure of 1,3,5-Tri(phenylethynyl)benzene
Authors: Bochkarev Mikhail N. , Katkova Marina A. , Fedorova Elena A. , Makarenko Natalya P. , Schumann Herbert , Girgsdies Frank 
Published: February 2015

Abstract
1,3,5-Tri(phenylethynyl)benzene 1 obtained by coupling triiodobenzene with phenylacetylene shows an unusual non planar molecular structure.
Synthesis, IR and X-Ray Studies of Tetra(N,N′-tetraethyl-N″-benzoyl- phosphorictriamide)-tetra(μ-3-methoxo)-tetra(methanol)tetra-NickeI(II)
Authors: Ovchynnikov Vladimir A. , Amirkhanov Vladimir M. , Kapshuk Anatoliy A. , Sliva Tatyana Yu. , Glowiak Tadeusz , Kozlowski Henryk 
Published: February 2015

Abstract
A new nickel(II) complex with N,N′-tetraethyl-N″-benzoylphosphortriamide (HL = C6H5C(O)N(H)P(O)(NEt2)2) of composition Ni4L4(OCH3)4·(HOCH3)4 (1) has been synthe­ sized. The crystal and molecular structure of 1 has been determined from the X-Ray diffraction data (tetragonal, space group P4̄21c with a = 17.000(2) Å, c = 15.338(3) Å, Z = 2; R = 0.0399 for 1412 unique reflections). The structure is made up of cubane-like tetramers. In the corners of a cube there are 4 atoms of nickel and 4 atoms of oxygen of methoxy groups. The nickel atoms are characterized by a slightly distorted octahedral environment, which consists of three oxygen atoms of methoxy groups, carbonylic and phosphorylic oxygen atoms of the ligand L-, and an oxygen atom of a methanol molecule. The ligands L- coordinate to the metal ion forming a chelate via the oxygen atoms of carbonylic and phosphorylic groups.
Reaktion von [Co(But
2PH)2I2] mit [Ru3(CO)12]: Synthese und Röntgenkristallstrukturanalyse von [Ru3(CO)6(μ-H)(μ-I)2(μ-PBut
2)(But
2PH)]/ Reaction of [Co(But
2PH)2I2] with [Ru3(CO)12]: Synthesis and X-Ray Crystal Structure of [Ru3(CO)6(μ-H)(μ-I)2(μ-PBut
2)(But
2PH)]
Authors: Graf Marion , Merzweiler Kurt , Bruhn Clemens , Böttcher Hans-Christian 
Published: February 2015

Abstract
[Co(But
2PH)2I2] (1) reacts with [Ru3(CO)12] in refluxing toluene to give a mixture of products including the novel metal clusters [Ru3(CO)6(μ-H)(μ-I)2(μ-PBut
2)(But
2PH)] (2) and [Ru3(CO)7(μ-H)(μ-I)(μ-PBut
2)2] (3) besides the known complex [Ru3(CO)8(μ-H)2(μ3- PBut)(But
2PH)] (4). No cluster expansion products could be observed. Thus the cobalt compound acts merely as a phosphine and iodine transfer reagent. The molecular structures of the metal complexes 1 and 2 were determined by single-crystal X-ray structure analyses. 1 crystallizes in the tetragonal space group P4̄21c with a = 13.230(3), b = 13.230(3), c = 14.788(3)Å, V = 2588.4(9)A . 2 crystallizes in the monoclinic space group P21/c with a = 18.161(2), b = 10.292(2), c = 18.381(2)Å, β = 108.73(10)°, V= 3253.7(8)Å3.
Zur Kristallstruktur von Ho2Se3/ On the Crystal Structure of Ho2Se3
Authors: Urland Werner , Person Helmut 
Published: February 2015

Abstract
Starting from HoSe2-x powder and holmium metal bright brownish-yellow, plate-like single crystals of Ho2Se3 could be prepared by chemical transport with AlCl3. Holmium sesquiselenide crystallizes in the Sc2S3-type structure, space group Fddd, with lattice constants a = 1140,7(2), b -812,6(1) and c = 2423,9(3) pm.
Cobalt(II) Derivatives of Cyclic Phosphazenes: Synthesis, Characterization and Fungicidal Behaviour
Authors: Baranwal B. P. , Das S. S. , Singh Poonam 
Published: February 2015

Abstract
Chlorine atoms of hexachlorocyclotriphosphazene were substituted with -NH.C2H5, -NH.CH2C6H5 and -OC2H5 to yield organotriphosphazene ligands. Anhydrous cobalt(II) chloride formed a number of addition complexes with these ligands in different stoichiometric ratios. On the basis of electronic and IR spectra, magnetic moment, conductivity meas­urements and molecular weight determination, structures of these complexes have been sug­gested. The complexes were screened for their antifungal activities against Aspergillus flavus and Aspergillus niger.
Functionalized 1,1-Ethene Dithiolates as Ligands, V [1]. Synthesis and Crystal Structure of Palladium(II) and Platinum(II) Complexes with Dithioylidene Barbituric Acid Ligands. Molecular Structure of a 2,6-Diaminopyridine-Platinum(II) Barbiturate Complex
Authors: Weigand Wolfgang , Plener Veronika , Nöth Heinrich , Krossing Ingo , Knizek Jörg , Schmidt Martin 
Published: February 2015

Abstract
The 1,1-ethene dithiolato ligands (dithioylidene barbituric acids) 2a-f react with palladium(II) and platinum(II) compounds L2MCI2 [M = Pd, Pt; L = PEt3, PBu3, PPh3, 1/2 dppe, 1/2 (-)-DIOP, 1/2 2,9-dimethyl phenanthroline] to give the 1,1-ethene dithiolato metal complexes

. Compound 4a forms a 1:1 adduct (8) with 2,6-diaminopyridine. The compounds were characterised on the basis of their IR and NMR (1H, 13C, 31P) spectra. Complexes 4a, 4c, and 5a were further studied by X-ray structural analysis. The barbituric unit in 4a undergoes self-assembly through multiple hydrogen-bonding with complementary 2 ,6-diaminopyridine yielding the supramolecular complex 8
Synthesis and Conformation of Nucleoside 5'-S-Thiosulfates
Authors: Orzeszko Andrzej , Niedźwiecka-Komaś Anna , Stolarskic Ryszard , Kazimierczuk Zygmunt 
Published: February 2015

Abstract
Reaction between 5′-bromo-5′-deoxy- (or 5′-tosyl-) nucleosides and sodium thiosulfate gives the respective 5′-S-thiosulfates (nucleoside Bunte salts). Conformation and some physicochemical properties of the new nucleotide analogs are described
Synthesis and Dimroth Rearrangement of 6-Cyano-l,2,4-triazolo- [4,3-a]pyrimidin-5- and 7-ones. A Novel Alkylation with Orthoesters and a New Participation of the Cyano Group in the Rearrangement
Authors: El Ashry E. S. H. , El Kilany Y. , Rashed N. , Mousaad A. , Assafir H. 
Published: February 2015

Abstract
The cyclization products of 5-cyano-2-hydrazino-6-phenyl-3,4-dihydropyrimidin-4-one (6) with one carbon inserting agents have been confirmed to be of the 1,2,4-triazolo[4,3-a]pyrimidin- 5(8H)-ones type and not the respective 7-ones, by comparing their alkylated derivatives 10a, 11a, 27 and 28 with the product from the cyclization of the 3-methyl and 3-benzyl derivatives of 6. A novel alkylation process was found when triethyl orthoformate was used as a cyclizing agent. Dimroth rearrangement of 8, 14, 15, 24, 34 and 36 with 2% ethanolic KOH gave the respective triazolo[1,5-a]pyrimidinone 13, 18, 19, 25, 38 and 40, respectively. Using 10% ethanolic KOH led to a novel participation of the cyano group in the rearrangement whereby 8a gave 7-imino-5-phenyl-l,2,4-triazolo[1,5-a]pyrimidine 22
Penol Catalyzed Claisen ortho Ester Rearrangment of Allylic Alcohols with Trimethyl-β-hoxy) ortho Propionate
Authors: Iqbal Fazila , Ateeq Humayun. S. , Malik Abdul , Zeeshan  , Ali Zulfiqar 
Published: February 2015

Abstract
Phenol catalyzed Claisen ortho ester rearrangment of allylic alcohols with trimethyl-β-(methoxy) ortho propionate can be affected in relatively quick time and lower temperature with only 1.5 equivalents of ortho ester. The rearrrangement does not experience undesirable side reactions reported earlier in literature [3]
Arsenic(III), Antimony (III) and Bismuth(III) Thiobenzoates: Crystal and Molecular Structures of M(SOCR)3 and PhSb(SOCPh)2
Authors: Singh Prit , Singh Sudha , Gupta Vishnu D. , Nöth Heinrich 
Published: February 2015

Abstract
Tris-thiobenzoates, Arsenic, Antimony, Bismuth Tris-thiobenzoates of arsenic, antimony and bismuth, M(SOCR)3 have been obtained from their oxides and characterized. In the X-ray crystal structure determinations of these, the group 15 atom and the three covalently bonded sulfur atoms are found to constitute a trigonal pyramid, the central atoms lie at a C3 axis. In the bismuth complex the thiobenzoate ligand tends to chelate. However, three comparatively short intermolecular M···S interactions are significant features for these molecules resulting in stacking of trigonal prisms providing an essentially six coordinate environment around arsenic and antimony and a nine-coordinate one for bismuth. The structure of PhSb(SOCPh)2 can be considered
Tetrazinn(II)-und Bariumtrizinn(II)-tetrakis[μ3 -tri-ter/-butyIsilylphosphan- diid]-Verbindungen mit einem Tetrametallatetraphosphacuban-Gerüst / Tetratin(II) and Barium Tritin(II) Tetrakis[μ3-tri-rm-butylsilylphosphandiide] Compounds with a Tetrametallatetraphosphacubane Core
Authors: Westerhausen Matthias , Krofta Mathias , Wiberg Nils , Knizek Jörg , Nöth Heinrich , Pfitzner Arno 
Published: February 2015

Abstract
The metalation of tri-terr-butylsilylphosphane with bis[bis(trimethylsilyl)amino]stannylen yields nearly quantitatively the tetrameric tin(II) tri-terf-butylsilylphosphandiide with a central Sn4P4 cubane moiety. Barium bis[tri-tert-butylsilylphosphanide] is accessible via the reaction of tri-tert-butylsilylphosphane with barium bis[bis(trimethylsilyl)amide] in the molar ratio 2 : 1 . This phosphanide reacts with bis[bis(trimethylsilyl)amino]stannylen to give barium tritin(II) tetrakis[μ3-tri-tert-butylsilylphosphandiide]. Crystallographic data of 1: P 212121, T = 193 K, a = 1532.6(3), b = 2120.2(4), c = 2194.0(5) pm, V = 7.129(3) nm3, Z = 4, R, = 0.0360 (9132 observed data [I > 2a( f) ] ) , wR2 = 0.1064 (all data); crystallographic data of 3: P 21/c, T = 193 K, a = 1927.35(1), b = 1799.27(2), c = 2201.35(2) pm, β = 93.010(1)°, V = 7.6234(1) nm3, Z = 4, R1 = 0.0321 (11993 observed data [I > 2σ(/)]), wR2 = 0.0772 (all data).
The Structure of Lithiumiodide 3-Tetrahydrofuran
Authors: Nöth Heinrich , Waldhör Ralf 
Published: February 2015

Abstract
LiI-3THF was obtained from the reaction of tmp2AH (tmp = tetramethylpiperidino) with Li-AsHPh in toluene/THF. It is more, conveniently prepared from LiH and iodine in THF. It forms molecule in the lattice, the Li ion being tetracoor-dinated in a slightly distorted tetrahedral fashion.
Benzo-18-krone-6 -Acetonitril (1/2): Kristallisation und Tieftemperatur- Röntgenstrukturanalyse / Benzo-18 -crown-6 -Acetonitrile (1/2): Crystallization and Low-Temperature X-Ray Analysis
Authors: Wijaya Karna , Moers Oliver , Blaschette Armand , Jones Peter G. 
Published: February 2015

Abstract
Benzo-18 -crown-6 -Acetonitrile (1/2), Crystal Structure Single crystals of the title complex resulted fortuitously during an attempt to co-crystallise MeN(SO2Me)2 with benzo-18-crown-6 from an MeCN solution at -30 °C. The crystal structure has been determined via data collection at -100 °C (monoclinic, space group P21/n, Z = 4). The nitrile molecules are located with their me­ thyl groups above and below the plane of the 18-membered crown ring, the Me hydrogen atoms being rotationally disordered about the MeCN axes; C(methyl)···O(crown) distances range from 309.4(3) to 384.9(3) pm.
Mesitylene Osmium(II) Complexes Containing the Functional Phosphane tBuP(CH2CO2Me)2 and Anionic Species Derived Thereof as Bi- and Tridentate Ligands
Authors: Henig Gerhard , Werner Helmut 
Published: February 2015

Abstract
The dichloroosmium(II) compound [(mes)OsCl2(L)] (2) with L = tBuP(CH2CO2Me)2 reacts with one or two equivalents of AgPF6 to give the mono- or dicationic complexes 3 and 4 containing the phosphanediyldiester as a bi- or tridentate chelating ligand. Complex 4 undergoes, in the presence of water, partial hydrolysis to give the difluorophosphatoosmium(II) derivative 5 in quantitative yield. Treatment of 4 with two equivalents of KOtBu affords by deprotonation at both CH2 groups of L the neutral complex 6, in which one PCHCO2Me unit of the dianionic ligand |tBuP(CHCO2Me)2]2- forms a five-membered and the other PCHCO2Me unit a three-membered ring with the metal. The reaction of 6 with water leads selectively to the formation of the chelate complex 7 containing the phosphanediylbis(carboxylate) [tBuP(CH2CO2)2]2- as a tripodal ligand.
Kristallstruktur des Doppelkomplexsalzes trans-(py2CH2)[Pt(OH)2(ox)2]transs-(py2CH2)[Pt(OH)(ox)2(H2O)]2·4H2O / Crystal Structure of the Double Complex Salt trans-(py2CH2)[Pt(OH)2(ox)2](H2O)]2·4H2O
Authors: Uttecht J.-G. , Preetz W. 
Published: February 2015

Abstract
By treatment of [Pt(ox)2]2- with hydrogen peroxide the octahedral trans-[Pt(OH)2(ox)2]2- is formed. From the saturated aqueous solution in the presence of dipyridiniomethane dications single crystals of the double complex salt trans-(py2CH2)[Pt(OH)2(ox)2] trans-(py2CH2)[Pt(OH)(ox)2(H2O)]2 · 4H2O were grown and an X-ray structure determination (tricli­nic, space group P1̄, a = 8.649(1), b = 11.189(3), c = 12.731 (2) Å, α = 79.075(12), β = 80.725(8), γ= 73.932(13)°, Z = 1) has been performed. The centrosymmetric trans-[Pt(OH)2(ox)2]2- is connected via hydrogen bonds between its hydroxide groups and the aqua ligands of two protonated complex anions trans-[Pt(OH)(ox)2(H2O)]- .
Neuartige Synthese und Molekülstruktur von Benzylkalium (thf) [KCH2C6H5]2 / Novel Synthesis and Molecular Structure of Benzyl Potassium (thf)[KCH2C6H5]2
Authors: Westerhausen Matthias , Schwarz Wolfgang 
Published: February 2015

Abstract
The reaction of potassium with hexamethyldi-stannane in a refluxing solvent mixture of toluene and tetrahydrofuran (ratio 10:1) yields the red tetrahydrofuran adduct of benzyl potassium (thf)[KCH2C6H5]2 due to the metalation of toluene by the potassium trimethylstannanide intermediate. The solid state structure of (thf)[KCH2C6H5]2 contains dimers with only one potassium coordinated to a tetrahydrofuran molecule. These dimers form a polymer through benzyl bridging with shortest K-C distances at 292 pm.
3,10,17,24-Tetra(1-methylethyl)-[29H,31H-tetrapyrido[2,3-b:2′,3′-g:2″-3″-I:2‴,3‴ -q]porphyrazinato-(2-)N29,N30,N31,N32]-nickel- [Eu(fod)3]4- Ein lösliches Pyridoporphyrazin / 3,10,17,24-Tetra(1-methylethyl)- [29H,31H-tetrapyrido[2,3-b:2′,3′-g:2″-3″-I:2‴,3‴-q]porphyrazinato-(2-)N29,N30,N31,N32]-nickel-[Eu(fod)3]4 - A Soluble Pyridoporphyrazine
Authors: Eichinger Karl , Brunmair Christoph , Bucher Martin 
Published: February 2015

Abstract
Starting from diethyl 5-(methylethyl)pyridine- 2,3-dicarboxylate the crystalline and highly soluble complex 3,10,17,24-Tetra(1-methylethyl)- [29H,31H-tetrapyrido[2,3-b:2′, 3′, -g:2″-3″-I:2‴, 3‴-q]porphyrazinato(2-)N29,N30,N31 ,N32]- nickel-[Eu(fod)3]4 was prepared. In this compound each europium ligand is coordinated to a pyridine N-atom and neighboured N-atom of the porphyrazine ring.
Untersuchungen zum ternären System Bi/Te/O, III. Bestimmung thermodynamischer Daten der ternären Verbindungen/Investigations on the Ternary System Bi/Te/O,III. Determination of Thermodynamic Data of Ternary Compounds
Authors: Schmidt P. , Hennig C. , Oppermann H. 
Published: February 2015

The phase relations in the ternary system Bi/Te/O have been determined in previous studies by solid state reactions. Thermodynamical data have now been obtained for the pertinent equilibria. The heats of solution of Bi2O3, Bi12TeO20, Bi10Te2O19, Bi16Te5O34, Bi2TeO5, Bi2Te2O7, Bi2Te4O11 and TeCl4 were determined in 4N HCl. From these the enthalpies of formation of bismuth tellurites at 298 K have been derived:
⊿H°b (Bi12TeO20, f, 298) = -901,6 ± 8 kcal/mol,
⊿H°b (Bi10Te2O19, f, 298) = -856,1 ± 9 kcal/mol,
⊿H°b (Bi16Te5O34, f, 298) = -1519,5 ± 17 kcal/mol,
⊿H°b (Bi2TeO5, f, 298)= -222,8 ± 3 kcal/mol,
⊿H°b (Bi2Te2O7, f, 298)= -299,4 ± 4 kcal/mol,
⊿H°b (Bi2Te4O11, f, 298)= -448,2 ± 7 kcal/mol.
Die Kristallstrukturen von [(TMEDA)LiCl]2·Toluol und [(MeCN)2LiCl]n
Authors: Chitsaz Soheila , Pauls Jochen , Neumüller Bernhard 
Published: February 2015

Abstract
Single crystals of [(TMEDA)LiCl]2 · toluene (1) and [(MeCN)2LiCl]n (2) can be obtained by dissolving LiCl in TMEDA or acetonitrile and crystallization (after addition of toluene for 1) at -30 °C. 1 is a dimer in the solid state while 2 is polymeric. 1 crystallizes in the space group I 2/a, Z = 4, with lattice dimensions at -90 °C: a = 1475.3(1), b=1112.7(2), c = 1615.0(2) pm, β = 103.44(1)°; Rx = 0.0739 with a disorder of the TMEDA ligand in two twist-positions. Crystals of 2 possess the space group Pbcm, Z = 4, with lattice dimensions at -80 °C: a = 1256.8(2), b = 775.2(1), c = 758.6(1) pm;R1 = 0.0419.
Preparation and Structure of Cyclic Gallium(III) and Gallium(II) 2-Amino-ethyl-amides
Authors: Schmidt Eva S. , Schier Annette , Mitzel Norbert W. , Schmidbaur Hubert 
Published: February 2015

Abstract
The reaction of N,N′-di(tbutyl)-ethane- 1,2-diamine with NaH followed by anhydrous GaCl3 (molar ratios 1:2 :1) gives mainly an insoluble bis(diamido)gallium chloride together with a low yield (28%) of a soluble monocyclic dichlorogallium-[2-(tbutylamino)-ethyl-(tbutyl)amide], Cl2Ga(tBuNH-CH2CH2-NtBu) 1, the structure of which has been determined. Metallation of the same diamine with tbutyl-lithium and GaCl3 (1:2:1) gave small quantities of the corresponding dinuclear, bicyclic gallium(II) compound 2, [(tBuNH-CH2CH2-NtBu)GaCl]2 with a Ga-Ga single bond connecting the two units, as again shown by a single crystal X-ray diffraction analysis.
Reactions of Amino-imino-boranes with Transition Metal Halides and Substituted Transition Metal Halides
Authors: Böck Barbara , Nöth Heinrich , Wietelmann Ulrich 
Published: February 2015

The aminoiminoborane tmp-B=NCMe3 (1) adds to TiBr4 or ZrCl4 in a 1:1 ratio while PdCl2 adds 1 in a 1:2 ratio. In these new compounds the NBN unit is almost linear and the configuration corresponds to an allene. On the other hand 1 and Ti(OR)4 compounds and Ti(NMe2)4 give N metallated diaminoboranes tmp-B(X)-NCMe3EX3 (X = OR, NMe2). Mixed compounds Ti(OR)3-nXn lead to diaminoboranes with BOR groups while the TiCl bond inserts into the B = N bond of 1 to produce tmp-BNMe2-NCMe3TiCl3. Hydrolysis of this compound leads to a spirocyclic dititanoxane with a short linear Ti-O-Ti bond and pentacoordinated Ti centers carrying two Cl atoms each. Spirocycles with a BN2E (E = Ti, Nb, Ta, Pd) unit are formed when 1 is allowed to react with TiCl4, NbCl5, TaCl5 and PdCl2. The palladium compound 16 is dimeric, and dimerization occurs via Pd-Cl bridges.
The aminoiminoborane tmp-B=NC6H3-2,6-iPr2 reacts with the titanium compounds in the same manner as 1, however without formation of spirocycles.
A Curious Case of Partial Spontaneous Resolution on Crystallization of a Racemate. The Crystal and Molecular Structures of N-Acetyl-DL-alanine Methylester and iV-Acetyl-L-alanine Methylester
Authors: Müller Gerhard , Lutz Martin 
Published: February 2015

Abstract
N-Acetyl-L-alanine methylester crystallizes in the orthorhombic space group P212121 with one molecule in the asymmetric unit (a = 7.768(1), b = 9.606(1), c = 10.215(2) Å, Z = 4). The individual molecules are linked into infinite strands by intermolecular hydrogen bonds between the amide hydrogen atom as donor and the acetyl oxygen atom as acceptor. The strands run parallel to the crystallographic b axis. The respective racemate, N-acetyl-DL-alanine methylester, crystallizes in the monoclinic space group P 21/n with three molecules in the asymmetric unit (a = 14.442(3), b = 8.467(2), c = 19.336(5) Å, β = 93.68(1)°, Z = 12). Again, the individual molecules are linked into infinite strands by N-H···O= Cacetyl hydrogen bonds which run along the crystallographic a axis. The individual strands are made up of molecules of opposite chirality in a 2:1 ratio. More specifically, one set of strands consists of molecules in the sequence [D, D, L,]∞ while a second set has the sequence [L, L, D]∞ as imposed by the centrosymmetry o f the space group. Thus, although crystals o f N-acetyl-DL-alanine methylester contain equal amounts of the molecules of opposite chirality, the strand formation through intermolecular hydrogen bonds leads to an incom plete resolution of the racemic mixture of molecules within one strand. The reason for the preference of the observed structure o f N-acetyl-DL-alanine methylester over spontaneous resolution is seen in the optimization of hydrogen bonding within one strand versus the overall crystal packing energy. Some principles of the crystallization of achiral molecules, chiral molecules, and racemates are briefly reviewed, as is the phenomenon of spontaneous resolution.
Preparation and Structure of Lithium Bis[cis-ethene-l,2-di(tbutylamido)]gallate(III) Tetrahydrofuran
Authors: Schmidt Eva S. , Mitzel Norbert W. , Schmidbaur Hubert 
Published: February 2015

Abstract
The dilithium diamide reagent obtained from N,N′-di(tbutyl)-1,4-diazabutadiene and two equivalents of lithium metal reacts with anhydrous gallium trichloride in tetrahydrofuran / hexane, followed by treatment with metallic potassium, to give the title compound in about 40% yield. Cyclic imides of gallium(III) and gallium(II) are by-products of this process. The structure of Li{[cis-C2H2(NtBu)2]2Ga} has been determined from single crystals containing one mole equivalent of tetrahydrofuran. The gallium atom is chelated by two diamide ligands. One of the five-membered chelate rings is planar while the second one is folded at its nitrogen atoms. The lithium atom is η4 -coordinated to the 1,4-diazabutene(2) unit of this ring and further to the oxygen atom of the solvent molecule.