bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zur Chemie des Dimesityleisens. X. Mesityleisenkomplexe [FeMes(X)]2 mit zentraler {Fe2(μ‐Mes)2}‐Einheit (Mes = C6H2‐2,4,6‐(CH3)3)
Authors: Müller H. , Seidel W. , Görls H. 
Published: December 2004

AbstractDurch partielle Acidolyse von Fe2Mes4 1, mit 2,6‐di‐tert‐butyl‐substituierten Phenolen gelangt man zu dimeren Komplexen [{MesFe(OAryl)}2] der Koordinationszahl drei am Fe‐Atom. Setzt man 1 mit 1,3‐Diketonen ebenfalls im Verhältnis 1:2 um, entstehen die Verbindungen [{MesFe(diketonat)}2] mit Koordinationszahl vier. In beiden Komplextypen liegt eine zentrale {Fe2(μ‐Mes)2}‐Einheit mit kurzen Fe—Fe‐Abständen von 2,56 bis 2,63 Å vor (1: 2,615 Å). Bricht man die Reaktion von 1 mit HO‐Aryl bei einem Molverhältnis 1:1 ab, lassen sich die Primärprodukte [Fe2(μ‐Mes)2Mes(OAryl)] isolieren. Die Gemischtligandenkomplexe können zu {Fe(OAryl)2} bzw. {Fe(diketonat)2} weiterreagieren. Die Strukturen von [Fe2(μ‐Mes)2(OC6H2‐2,6‐tBu2‐4‐CH3)2] (3), [Fe2(μ‐Mes)2Mes(OC6H2‐2,4,6‐tBu3)] (5) und [Fe2(μ‐Mes)2{(tBuCO)2CH}2] (9) werden mitgeteilt.
Reactions of (Nonafluorocyclohexen‐1‐yl)xenon(II) Hexafluoroarsenate with Halide Anions
Authors: Frohn H. J. , Bardin V. V. 
Published: December 2004

AbstractThe products of the reaction between the electrophilic alkenylxenonium cation [1‐Xe+–C6F9] and the halide anions I−, Br−, Cl− and F− depend on the hardness of the halide anion. With the soft halides I− and Br− Xe(II) is formally displaced by halogen as well in basic MeCN as in superacidic (AHF1), whereas with hard fluoride and chloride no reaction takes place in AHF. In MeCN F− initiates the formation of alkenyl radicals, which abstract hydrogen from the solvent, whereas Cl− exhibits borderline character: RH and RCl formation. Possible reaction paths are discussed.The reactivity of the arylxenonium cation [C6F5Xe]+ in AHF toward halide ions is reported and the relative electrophilicity of the cations [C6F5Xe]+ and [1‐Xe+–C6F9] is determined by the competitive reaction with Cl−. In addition the synthesis of cyclohexene 1‐CF3–C6F9 from C6F5CF3 and XeF2 is performed and its electrophilicity is compared with that of the aromatic compound C6F5CF3.
Reaction of Hexamethyldisilazane with Borane in Tetrahydrofuran
Authors: Wrackmeyer Bernd , Schwarze Bernd 
Published: December 2004

AbstractHexamethyldisilazane 1 reacts with borane in tetrahydrofuran (THFBH3, 2) first by formation of an adduct (Me3Si)2NHBH3 (3), and then either to the N,N‐bis‐(trimethylsilyl)‐μ‐aminodiborane 5 or to the mixture of 5 and N‐trimethylsilyl‐μ‐aminodiborane(6) 6, depending on the reaction conditions. The compounds 5 and 6 can be quantitatively converted to the N,N′,N″‐tris(trimethylsilyl)borazine 4. Three intermediates can be identified, namely N,N‐bis(trimethylsilyl)borane 7, N,N‐bis(trimethylsilyl)amino(N′‐trimethylsilylamino)borane 8 and N‐trimethylsilylaminoborane‐trimer. All products and intermediates were characterized by multinuclear NMR spectroscopy, and coupling constant 1J(29Si, 15N) were measured from 29Si NMR spectra by using the Hahn‐echo‐extended (HEED) INEPT pulse sequence.
Binary alkali metal compounds with the zintl anions [Ge9]4− and [Sn9]4−
Authors: Von Schnering H. G. , Baitinger M. , Bolle U. , Carrillo‐Cabrera W. , Curda J. , Grin Y. , Heinemann F. , Llanos J. , Peters K. , Schmeding A. , Somer M. 
Published: December 2004

AbstractThe binary germanides M12Ge17 and M4Ge9 (M  Na, K, Rb, Cs) and the stannides M12Sn17 and M4Sn9 (M  K, Rb, Cs) were identified by a combination of direct synthesis, thermogravimetric analysis, vibrational spectroscopy, X‐ray powder data and single crystal structure analysis. The M12E17 phases contain the cluster anions [E9]4− and [E4]4− in the ratio 1:2, forming a hierarchical structure with the cluster anions at the atomic positions of the hexagonal Laves phase MgZn2. Like the M4E4 phases, the M4Ge9 compounds are hierarchical derivatives of the cubic Cr3Si structure but with [Ge9]4− anions. The thermogravimetric analyses give strong evidence for the existence of at least one more phase with [E9]4− and [E4]4− clusters and of the clathrate phases M6E136 in addition to the well‐known M8E44□2 chlathrates.
Phosphanimin‐ und Phosphaniminato‐Komplexe von Magnesium. Die Kristallstrukturen von [MgBr1,25I0,75(Me3SiNPMe3)(OEt2)], [MgI2(Me3SiNPMe3)2], [Mg2I2(Me3SiNPMe2CH2)Me3SiNPMe2CH2CH(Me)O)(OEt2)] und [MgBr(NPMe3)]4·C7H8
Authors: Müller Anita , Krieger Matthias , Neumüller Bernhard , Dehnicke Kurt , Magull Jörg 
Published: December 2004

AbstractAls Hauptprodukte der Umsetzungen des silylierten Phosphanimins Me3SiNPMe3 mit den Grignard‐Reagentien EtMgBr und MeMgl wurden die carbanionischen Phosphaniminato‐Derivate [XMg(CH2Pme2NSiMe3)]n (X  Br, I) isoliert. Als Nebenprodukte wurden [MgBr1,25I0,75(Me3SiNPMe3)(OEt2)], [Mgl2(Me3SiNPMe3)2] und [Mg2I2(CH2PMe2NSiMe3)(O(Me)CHCH2PMe2NSiMe3(OEt2)] durch röntgenographische Strukturanalysen identifiziert. Den Phosphaniminato‐Komplex [MgBr(NPMe3)]4 · C7H8 mit Heterocuban‐Struktur erhielten wir durch Metathese‐Reaktion aus [ZnBr(NPMe3)]4 und RMgBr (R  Ph, Mes).
Synthesen und Kristallstrukturanalysen von Tetraalkylphosphonium‐, ‐arsonium‐ und ‐stiboniumtriiodiden
Authors: Breunig H. J. , Denker M. , Ebert K. H. , Lork E. 
Published: December 2004

AbstractDie Reaktion von Me4EI (EP, As), Me3EtSbI, Me2Et2SbI, MeEt3SbI oder Et4SbI mit I2 im Substanzgemisch ohne Lösungsmittel führt zu den entsprechenden Triiodiden Me4EI3 (EP, As), Me3EtSbI3, Me2Et2SbI3, MeEt3SbI3 oder Et4SbI3. Me4SbI3 entsteht in reversibler Reaktion durch Zugabe von I2 zu (Me4Sb)3I8 oder durch Umsetzung einer ethanolischen Lösung von Me4SbI mit einer Lösung von Iod in Benzol. Über die Kristallstrukturen von Me4EI3 (EP, Sb) und Me3EtSbI3 und die Synthese der neuen Verbindungen wird berichtet.
[Li7(CHPMe2NSiMe3)3(OSiMe2nBu)]2, ein Gemischtligand‐Li14‐Cluster mit dem Carbdianion (CHPMe2NSiMe3)2−
Authors: Müller Anita , Neumüller Bernhard , Dehnicke Kurt , Magull Jörg , Fenske Dieter 
Published: December 2004

AbstractDie Titelverbindung (farblose, feuchtigkeits‐ und sauerstoffempfindliche Kristalle) entsteht bei der Reaktion von [LiCH2PMe2NSiMe3]4 mit wasserfreiem Zink‐ oder Cobaltchlorid in einer Toluolsuspension in Gegenwart von Siliconfett (–OSiMe2‐)n und n‐Butyllithium. Sie wird durch Multikern‐NMR‐Spektroskopie und durch Kristallstrukturanalysen zweier kristallchemisch verschiedener Individuen charakterisiert.1. Raumgruppe P1, Z = 1, Gitterkonstanten bei −70 °C: a = 1272,0; b = 1392,6; c = 1417,6 pm; α = 115,33°; β = 96,75°; σ = 106,81°; R = 0,042.2. Raumgruppe P21/n, Z = 2, Gitterkonstanten bei ‐50 °C: a = 1424,8; b = 1457,1; c = 1997,0 pm; β = 90,32°; R = 0,069.
NaPr9S2[SiO4]6: Ein Sulfidsilicat des Praseodyms mit Bromapatitstruktur
Authors: Sieke Corinna , Schleid Thomas 
Published: December 2004

NaPr9S2[SiO4]6: A Sulfide Silicate of Praseodymium with the Structure of BromapatiteNaPr9S2[SiO4]6 is obtained as pale green single crystals of hexagonal columnar shape from reactions of Pr, Pr6O11, S, SiO2 and NaCl (850°C, 7 d) in fused evacuated silica tubes. The crystal structure (hexagonal, P63/m, Z = 1, a = 981.05(4), c = 689.68(2) pm) corresponds with a modified bromapatite structure where orthosilicate ([SiO4]4−) and sulfide (S2−) anions provide coordination numbers of eight and nine to the two crystallographically different cations. These occupy the positions 4 f (Na+ together with Pr3+ in a molar ratio of 1:3) and 6h (Pr3+ only) to realize an average Ca5Br[PO4]3‐type structure.
Kristallstruktur von (NH4)3SnF7: Ein Doppelsalz gemäß (NH4)3[SnF6]F und kein (NH4)4SnF8
Authors: Plitzko Christian , Meyer Gerd 
Published: December 2004

Crystal Structure of (NH4)3SnF7: A Double Salt According to (NH4)3[SnF6]F and not (NH4)4SnF8(NH4)3SnF7 is obtained as colourless single crystals from the reaction of NH4HF2 with tin powder at 300°C. The crystal structure (cubic, Pm3m, Z = 1, a = 602.5(1) pm at 293 K; a = 598.0(1) pm at 100 K) contains [SnF6]2− octahedra and lonesome F− ions surrounded by NH4+ cations only; it may be considered as a derivative of the Cu3Au‐type of structure according to Cu3[Au]□ (NH4)3[SnF6]F. The F− ions of the [SnF6]2− octahedra with their Sn4+ centre in the origin of the unit cell at m3m are disordered in different ways at 293 and 100 K, respectively.
Kristallstruktur, Schwingungsspektren und Normalkoordinatenanalyse von K2[IrCl5(NH3)]
Authors: Bernhardt E. , Preetz W. 
Published: December 2004

AbstractDie Röntgenstrukturanalyse von K2[IrCl5(NH3)] (orthorhombisch, Raumgruppe Pnma, a = 13,426(4), b = 10,015(2), c = 6,8717(7) Å, Z = 4) hat gezeigt, daß das Komplexanion [IrCl5(NH3)]2− (IrCl = 2,337–2,365, IrN = 2,067(10); NH = 0,73–0,79 Å) Cs‐Punktsymmetrie aufweist. Mit den röntgenographisch bestimmten Molekülparametern lassen sich die IR‐ und Raman‐Spektren durch Normalkoordinatenanalyse zuordnen. Die Valenzkraftkonstanten betragen fd(NH) = 5,88, fd(IrN) = 2,66, fd(IrCl) = 1,68 mdyn/Å.
Über den Einfluß von Temperatur, Druck und Substitution auf die Kristallstruktur von ARh2P2 (A = Ca, Sr, Eu, Ba)
Authors: Wurth A. , Johrendt D. , Mewis A. , Huhnt C. , Michels G. , Roepke M. , Schlabitz W. 
Published: December 2004

AbstractVier Verbindungen ARh2P2 (A = Ca, Sr, Eu, Ba) wurden durch Erhitzen entsprechender Elementgemenge dargestellt und hinsichtlich ihrer Kristallstruktur mit Hilfe von Einkristallmethoden charakterisiert. Sie kristallisieren in der tetragonalen ThCr2Si2‐Struktur (I4/mmm; Z = 2) und unterscheiden sich im wesentlichen durch ihre PP‐Abstände längs [001]. Diese reichen von 2,26 Å bei CaRh2P2 bis 3,74 Å bei BaRh2P2 und verändern sich drastisch im Zuge von Phasenumwandlungen 1. Ordnung durch Temperaturerhöhung bei EuRh2P2 sowie unter erhöhtem Druck bei SrRh2P2. Substitution übt ebenfalls einen großen Einfluß auf den Strukturfeinbau der Verbindungen aus.
Darstellung und Kristallstruktur von [P(C6H5)4][2,9‐{N,N′‐(2‐NH(C5H4N))}B10H8]
Authors: Nachtigal C. , Preetz W. 
Published: December 2004

Abstract[N(C4H9)4]2[B10H10] reagiert mit 2‐Aminopyridin unter Bildung eines Produktgemisches, aus dem durch Ionenaustauschchromatographie an Diethylaminoethyl(DEAE)‐Cellulose [2,9‐{N,N′‐(2‐NH(C5H4N))}B10H8]− isoliert werden kann. Die Röntgenstrukturanalyse an [P(C6H5)4][2,9‐{N,N′‐(2‐NH(C5H4N))}B10H8] (triklin, Raumgruppe P1, a = 10,1103(9), b = 11,5665(9), c = 14,877(2) Å, α = 102,600(8), β = 107,567(8) und γ = 96,487(7)°, Z = 2) beweist, daß 2‐NH2‐(C5H4N) über beide N‐Atome an benachbarte B‐Atome der beiden quadratischen Ebenen des B10‐Clusters (B2N1 = 1,541(7) und B9N2 = 1,505(7) Å) unter Ausbildung eines Fünfringes gebunden ist.
Tetraammin‐Lithium‐Kationen zur Stabilisierung phenylsubstituierter Zintl‐Anionen: Die Verbindung [Li(NH3)4]2[Sn2Ph4]
Authors: Scotti Nicole , Zachwieja Uwe , Jacobs Herbert 
Published: December 2004

Tetraammine Lithium Cations Stabilizing Phenylsubstituted Zintl‐Anions: The Compound [Li(NH3)4]2[Sn2Ph4]Ruby‐red, brittle single crystals of [Li(NH3)4]2[Sn2Ph4] were synthesized by the reaction of diphenyltin dichloride and metallic lithium in liquid ammonia at −35°C. The structure was determined from X‐ray singlecrystal diffractometer data: Space group, P1, Z = 1, a = 9.462(2) Å, b = 9.727(2) Å, c = 11.232(2) Å, α = 66.22(3)°, β = 85.78(3)°, γ = 61.83(3)°, R1 (F ⩾ 4σF) = 5.13%, wR2 (F02 ⩾ 4σF) = 10.5%, N(F ⩾ 4σF) = 779, N(Var.) = 163.The compound contains to Sb2Ph4 isosteric centres [Sn2Ph4]2− as anions which are connected to rods by lithium cations in distorted tetrahedral coordination by ammonia. These rods are arranged parallel to one another in the b,c‐plane, but stacked along [100].
Bi24Ru3Br20: Ein pseudo‐tetragonales Subbromid mit [RuBi6Br12]‐Clustern und [Ru2Bi17Br4]‐Gruppen
Authors: Ruck Michael 
Published: December 2004

AbstractAus der Schmelzreaktion von Ru mit Bi und BiBr3 werden schwarze, metallisch glänzende und luftbeständige Kristalle des Subbromids Bi24Ru3Br20 erhalten. Die orthorhombische Kristallstruktur (Raumgruppe Pc21n, a = b = 1377,8(1) pm, c = 3222,3(4) pm, V = 6117,0 · 106 pm3) täuscht die Pseudosymmetrie der tetragonalen Raumgruppe P4/ncc vor, was zu mehrfach verzwillingten Kristallen führt. Die Struktur läßt sich formal in [RuBi6Br12]‐Cluster, [Ru2Bi17Br4]‐Stapel und [BiBr4]‐Gruppen aufgliedern.
Untersuchungen an Natriumtrifluormethylsulfonat – Kristallstruktur und Phasenumwandlung des Monohydrats und Natriumionenleitfähigkeit des wasserfreien Salzes
Authors: Jansen Martin , Korus Gabriele 
Published: December 2004

AbstractNach Kühl‐Guinier‐Simon‐Untersuchungen ist Natriumtrifluormethylsulfonatmonohydrat dimorph. Die Phasenumwandlung erfolgt bei −35°C. Die Raumtemperaturmodifikation kristallisiert monoklin in der Raumgruppe P21/c mit den Gitterkonstanten a = 941,6(5) pm, b = 654,3(2) pm, c = 1062,4(5) pm und β = 107,73(2)°. In der Kristallstruktur liegen Doppelschichten aus Trifluormethylsulfonatanionen vor, in denen die unpolaren CF3‐Gruppen einander zugewandt sind. Natrium wird von jeweils einem Sauerstoffatom aus vier verschiedenen Anionen sowie von zwei Kristallwassermolekülen koordiniert und erreicht eine verzerrt oktaedrische Koordination. Die Tieftemperaturmodifikation kristallisiert orthorhombisch in der Raumgruppe Pnma mit den Gitterkonstanten a = 645,31(9) pm, b = 538,03(9) pm, c = 1745,3(3) pm. Die Abgabe von einem Mol Kristallwasser erfolgt bei 136°C. Wasserfreies Natriumtrifluormethylsulfonat zeigt eine Phasenumwandlung in eine Hochtemperaturmodifikation bei 252°C, die eine gute Natriumionenleitfähigkeit zeigt (σ = 4,1 · 10−1 Ω−1 cm−1 bei 250°C).
Die NMR‐Spektren von CF3I, CF3IF2 und CF3IF4
Authors: Tyrra Wieland , Miczka Markus , Naumann Dieter 
Published: December 2004

The NMR Spectra of CF3I, CF3IF2, and CF3IF4The 19F‐NMR and 13C‐NMR spectra of CF3I, CF3IF2 and CF3IF4 were recorded in acetonitrile solution. The chemical shifts of the CF3‐groups are strongly dependent on the oxidation state of the iodine atom. With increasing oxidation state the resonances of the CF3‐groups in the 19F‐NMR spectra are characteristically shifted to high field, whereas in the 13C‐NMR spectra a characteristic shift to low field is measured. The absolute value of the coupling constants 1J(19F13C) increases with increasing oxidation state from 344 Hz (CF3I) via 354 Hz (CF3IF2) to 359 Hz (CF3IF4).
Synthesis of Alkylcyclophosphanes from Red Phosphorus – molecular structure of i‐Pr4P4 by gas electron diffraction
Authors: Steinicke A. , Thiele K.‐H. , Haaland A. , Sokolov V. I. , Volden H. V. 
Published: December 2004

AbstractA polyphosphide of the type (NaP)X 1 was obtained from red phosphorus and sodium in presence of small amounts of naphthalene in 1,2‐dimethoxyethane as solvent. 1 reacts with alkyl halides in dependence on the kind of alkyl group with formation of different alkylcyclophosphanes. As definite compounds Me5P5 2, Et5P5 3 (with not definite constitution), i‐Pr4P4 4 and t‐Bu4P4 5 could be isolated.1 was identified by X‐ray diffraction, 2–5 by means of their 1H, 13C, 31P n.m.r. and mass spectra. The molecular structure of 4 was identified by electron diffraction.
Kristallstrukturen und Schwingungsspektren von Tetrahalogenoacetylacetonatoosmaten(IV), [OsX4(acac)]−, X  Cl, Br, I
Authors: Dallmann K. , Preetz W. 
Published: December 2004

AbstractBei der Umsetung von Hexahalogenoosmaten(IV) mit Acetylaceton entstehen die Tetrahalogenoacetylacetonatoosmate(IV) [OsX4(acac)]− (X  Cl, Br, I), die säulenchromatographisch gereinigt und aus wäßriger Lösung als (Ph4P)‐ oder Cs‐Salze ausgefällt werden. Röntgenstrukturanalysen sind an Einkristallen von (Ph4P)[OsCl4(acac)] (1) (triklin, Raumgruppe P1, a = 9,9661(6), b = 11,208(2), c = 13,4943(7) Å, α = 101,130(9), β = 91,948(6), γ = 96,348(8)°, Z = 2), (Ph4P)[OsBr4(acac)] (2) (monoklin, Raumgruppe P21/n, a = 9,0251(8), b = 12,423(2), c = 27,834(2) Å, β = 94,259(7)°, Z = 4) und (Ph4P)[OsI4(acac)] (3) (monoklin, Raumgruppe P21/c, a = 18,294(3), b = 10,664(2), c = 18,333(3) Å, β = 117,68(2)°, Z = 4) durchgeführt worden. Der in der Reihe O < Cl < Br < I zunehmende trans‐Einfluß zeigt sich an den O.OsX′‐Oktaederachsen in verlängerten OsO.‐Abständen und der Verschiebung der OsO.‐Valenzschwingungen zu niedrigeren Frequenzen. Die OsX′‐Bindungslängen sind im Vergleich zu denen symmetrisch koordinierter XOsX‐Achsen etwas kürzer.
Locus of control and control perceptions and the relationship between life stress and psychological disorder
Authors: Nelson Dean W. , Cohen Lawrence H. 
Published: December 2004

ConclusionThe deleterious effects of negative life events were demonstrated, even with a relatively restricted range of negative experiences and the inclusion of a number of statistical controls. Employing a conservative multivariate regression model and a prospective design, the present study found that negative life events were consistently positively related to measures of psychological disorder. There was, however, no evidence for the moderating effects of dispositional locus of control beliefs and control perceptions of experienced life events, and it seems that the field awaits more refined conceptualization and measurement of life experiences and hypothesized moderator variables before explanatory and predictive models will yield significant and consistent returns.
Clinical approach to graft hepatic artery thrombosis following living related liver transplantation
Authors: Dalgic Aydin , Dalgic Buket , Demirogullari Billur , Ozbay Ferda , Latifoglu Osman , Ersoy Emin , Ahmet Mahli  , Ilgit Erhan , Ozdemir Hakan , Arac Mehmet , Akyol Gulen , Tatlicioglu Ertan 
Published: December 2004

Abstract: Hepatic artery thrombosis (HAT) has an occurrence rate of 1.7–26% following living donor liver transplantation (LDLT) and is one of the most common reasons for graft loss and mortality in this population. There is a higher incidence of HAT in pediatric recipients. The aim of this case report is to discuss clinical approaches for the treatment of HAT occurring in the early post‐operative period after LDLT. An 11‐month‐old, 7.8‐kg female with cirrhosis secondary to biliary atresia underwent LDLT at Gazi University Hospital in Ankara. The graft was a left lateral segment from her father with a left hepatic artery (HA) of 2 mm diameter and a graft weight/recipient body weight ratio of 2.0%. After an uneventful early post‐operative period, HAT was diagnosed by Doppler ultrasonography (USG) on the fifth post‐operative day. Following angiographic evaluation, immediate exploration and reanastomosis was performed using an operation microscope. Post‐operatively, the HA was patented by Doppler USG and graft function returned to normal. Now, 42 months later, the patient continues to do well with normal graft function, using a regimen of tacrolimus monotherapy for immunosuppression. In countries which have very limited resources for urgent re‐transplantation, given their serious donor shortage, graft salvage may be the only option for patient survival when HAT occurs. In these circumstances, early diagnosis and immediate revascularization may be the only method for graft salvage. A daily routine of Doppler USG examination in the early post‐operative period may provide a method for the early diagnosis of HAT, before liver enzymes are elevated and hepatic necrosis has begun.
The effect of aprotinin on transfusion requirements in pediatric orthotopic liver transplantation
Authors: Rentoul Toni M. , Harrison Victor L. , Shun Albert 
Published: December 2004

Abstract: The use of aprotinin to reduce blood loss by inhibiting fibrinolysis thereby decreasing transfusion requirements during orthotopic liver transplantation (OLT), is well‐documented in adults. We set out to test the hypothesis that the prophylactic use of aprotinin reduced blood product requirements during pediatric OLT.A retrospective study was performed, reviewing data from 24 OLTs performed over a 4‐yr period. Six patients did not receive aprotinin (group 1), while 18 (group 2) received a weight‐based dose of aprotinin. Both groups were comparable with respect to demographics, baseline characteristics and surgical variables except for a significantly more prolonged activated partial thromboplastin time (APTT) in the aprotinin group (p = 0.015). Despite the fact that median values for transfused volumes of red blood cells (78.3 vs. 36.7 mL/kg) and fresh frozen plasma (51.9 vs. 23.7 mL/kg) were more than halved in the aprotinin group, there was no statistical difference demonstrated. The failure to reach statistical significance can probably be explained by the small number in group 1 and a high level of scatter. All patients in group 1 required intraoperative transfusion of RBC and fresh frozen plasma (FFP) while two patients in group 2 did not require RBC and seven received no FFP. There were four patients in group 1 and 17 in group 2 who did not receive platelets while five in group 1 and 12 in group 2 did not receive cryoprecipitate. The differences between the groups in avoidance of these blood products did not reach statistical significance. There was little difference between groups with respect to albumin and crystalloid requirements. No statistical difference was demonstrated in intraoperative hematologic profiles between the two groups except during the anhepatic phase of surgery when there was a statistically significant more prolonged prothrombin time (p = 0.04) and a greater international normalized ratio (p = 0.027) in group 2.
Identification of new aromatic cytokinins in Arabidopsis thaliana and Populus × canadensis leaves by LC‐(+)ESI‐MS and capillary liquid chromatography/frit–fast atom bombardment mass spectrometry
Authors: Tarkowská Danuše , Doležal Karel , Tarkowski Petr , Åstot Crister , Holub Jan , Fuksová Květoslava , Schmülling Thomas , Sandberg Göran , Strnad Miroslav 
Published: December 2004

A search for naturally occurring aromatic cytokinins (ARCKs) in Arabidopsis thaliana plants and Populus × canadensis leaves led to the discovery of four new plant hormone substances: 6‐(2‐methoxybenzylamino)purine (ortho‐methoxytopolin, MeoT), 6‐(3‐methoxybenzylamino)purine (meta‐methoxytopolin, MemT) (Fig. 1) and their 9‐β‐D‐ribofuranosyl derivatives. These substances were identified by liquid chromatography electrospray ionization mass spectrometry [LC (+)ESI‐MS] and capillary‐liquid chromatography/frit‐fast atom bombardment–mass spectrometry [CapLC/frit‐FAB‐MS] after pre‐column derivatization. The chemical structures were subsequently confirmed by chemical synthesis. Because of lack of heavy labelled internal standards, the endogenous levels of methoxytopolins in A. thaliana plants, Populus × canadensis leaves and samples derived from cultures of Agrobacterium tumefaciens strain GV3101 were determined by enzyme‐linked immunosorbent assay (ELISA) of HPLC‐fractionated extracts. While the levels of MeoT, MemT and their ribosides in A. thaliana shoots and Populus × canadensis leaves were relatively low (approximately 0.25–10 pmol g−1 FW for MeoT and MemT, respectively), the A. tumefaciens strain produced up to 600 times more of the newly identified substances. Cytokinin activity of methoxytopolines was demonstrated in three bioassays testing their ability to stimulate tobacco callus growth, to delay chlorophyll degradation in excised wheat leaves, and to induce betacyanin synthesis in Amaranthus caudatus var. atropurpurea cotyledons. Notably, their anti‐senescing activity in the wheat leaf assay exceeded that of BAP and Z by almost 200%. Methoxytopolins are proposed to be new members of the biologically active aromatic cytokinin family, which might have specific physiological functions.The structures of 6‐(2‐methoxybenzylamino)purine (ortho‐methoxytopolin, MeoT) and 6‐(3‐methoxybenzylamino)purine (meta‐methoxytopolin, MemT).image