摘要:

Metal Chelates of Medical Interest, VI. – Synthesis of a Tripodal Triisocyanide Ligand and its Reaction with Na[99mTcO4]The tripodal triisocyanide ligand tris[3‐(2‐isocyanophenoxy)‐ propyl]amine, TARC (6), is prepared from tris(3‐chloropropyl)‐ amine (1) and the potassium salt of 2‐nitrophenole followed by reduction of the nitro functions and conversion of the primary amines into isocyanide functions by the method of Ugi et al. The structure of the intermediate tris[3‐(2‐nitrophenoxy)‐ propyl]amine (3) has been determined by X‐ray diffraction. Tripode6binds99mTc from nuclide generator

ISSN:0009-2940    

DOI:10.1002/cber.19911240802

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Reactions of an Amino Imino Borane with Phosphinic, Phosphonic, and Phosphoric AcidsControlled 1:1 reactions of R2P(O)OH with tmp – B = NtBu (1) (tmp = 2,2,6,6‐tetramethylpiperidino group) in hexane leads to R2P(O)OB(tmp)NHtBu (2). In most other cases mixtures of 2 with other products are obtained. Application of a 4:1 ratio of Me2P(O)OH and1results in the formation of pure [tBuNH3][B(OP(O)Me2)4] (3). Reaction of phosphonic acids with 1 in hexane at about –30°C leads preferentially to the addition of the acid to produce RP(O)[OB(tmp)NHtBu]2(4), while H3PO4reacts with1to yield OP[OB(tmp)NHtBu]3(6). Species containing tetracoordinated boron atoms are formed as well in dichloromethane as a solvent. Spectral data for the compounds2,4, and6reveal three‐coordinate boron atoms, confirmed by an X‐ray structure analysis of2a(R = CH3). This compound displays a fairly large B – O – P bond an

ISSN:0009-2940    

DOI:10.1002/cber.19911240803

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

(1,1′,3,3′‐Tetra‐tert‐butyl‐5,5′‐pentafulvalene)dithallium – Synthesis and Crystal Structure: a Contribution to the Discussion of Nonclassical TI(I)‐TI(I) InteractionsReaction of 1,1′,3,3′‐tetra‐tert‐butyl‐5,5′‐dihydropentafulvalenediyldilithium with stoichiometric amounts of thallium chloride affords the dinuclear complex (η5:(η5‐tBu4C10H4)Tl2(2). Compound2is air‐and moisture‐sensitive, and photolabile. It crystallizes in the space groupP•1 and consists of two (cyclopentadienyl)thallium units which are connected by a central C‐C bond and twisted against each other by 70°. The monomeric units of2form a two‐dimensional polymer with a zick‐zack chain of T1 atoms and a periphery of substituted cyclopentadienyl ligands. Rather short T1‐T1 contacts of 3.760 and 3.998 Å are formed within a dimeric substructure. The geometry of the cyclopentadienyl ligands around the shortest T1‐T1 bond is similar to

ISSN:0009-2940    

DOI:10.1002/cber.19911240804

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Crowded 3,5‐disubstituted pyrazoles, e. g. 3,5‐di‐tert‐butyl‐,3,5‐di‐tert‐butyl‐4‐methyl‐, or 3,5‐di‐tert‐butyl‐4‐ethylpyrazole [(tb)2Pz, (tb)2mPz, or (tb)2ePz, respectively], fail to react with activated trialkylboranes (e. g. BEt3* or BPr3*) at 110°C, even after prolonged heating. At 170°C the reaction of(tb)2Pzwith activated triethylborane gives the monomeric diethyl(3,5‐di‐tert‐butyl‐1‐pyrazolyl)borane(3). At 220–230°C the dimeric boracycles(4)2are mainly formed [X‐ray structure of(4a)2]. In contrast, the reactions of these crowded pyrazoles with tetraalkyldiboranes(6) commence just above room temperature. Diethylhydroborane adducts (5) of3and dimeric alkyl(3,5‐di‐tert‐butyl

ISSN:0009-2940    

DOI:10.1002/cber.19911240805

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Twofold lithiation of dibenzofuran (6) and dibenzothiophene (12) withn‐butyllithium/N,N,N′,N′‐tetramethylethylenediamine (TMEDA) inn‐hexane orn‐pentane followed by the reaction with chlorodiphenylphosphine yielded the title compounds4and5, respectively, The monophosphines 4‐(diphenylphosphino)dibenzofuran (11) and 4‐(diphenylphosphino)dibenzothiophene (15) were obtained analogously via the monolithium compounds9and14of the heteroarenes. In the case of dibenzofuran (6), it was shown that mono‐ and dilithiation is controll

ISSN:0009-2940    

DOI:10.1002/cber.19911240806

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

P4O7and P4O6S, Comparison of Molecular and Crystal StructureSingle crystals of P4O6S were grown for the first time. By X‐ray diffraction the space group (P21/c), the unit cell [α = 813.5(1),b= 938.3(1),c= 993.1(1) pm; β = 90.27(1)°], and the crystal and molecular structure have been determined. As compared to P4O7, the geometry of the P4O6cage remains virtually unchanged upon substitution of the terminal oxygen atom by a sulfur atom. Calculated charge distributions clearly confirm the experimental results. With the exception of P(1), to which the additional chalcogen atom is attached, the effective charges at all other atoms seem not to be affected by an exchange of the terminal oxygen atom by a sulfur

ISSN:0009-2940    

DOI:10.1002/cber.19911240807

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Metal‐Containing Heterocycles: Preparation, Properties, Reactions, LXXV1). — Synthesis of a Diphosphamolybdacyclopentene by Alkyne Insertion into the P ‐ P Bond of a DiphosphamolybdacyclopropaneInsertion of the alkyne RCCR (R = CO2Me) into the P ‐ P bond of the diphosphamolybdacyclopropane (5‐C5H5)‐(OC)2Mo‐PPh2‐PAr (2) [Ar = 2,4,6‐(tBu)3C6H2] results in the formation of the thermally and kinetically stable diphosphamolybdacyclopentene (η5‐C5H5)(OC)2Mo‐PPh2‐RC = CR‐PAr (3), which is characterized on the basis of mass, IR,31P{1H}

ISSN:0009-2940    

DOI:10.1002/cber.19911240808

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe X‐ray analyses of three 1,3,5‐tris(alkylamino)‐2,4,6‐trinitrobenzenes (alkyl = iPr, neopentyl,tBu;1d–f) show their benzene rings to be highly distorted towards boat (1diPrNH2) and twist‐boat (1e,f) forms. The patterns found for intramolecular donor‐acceptor interaction and hydrogen bonding depend on the conformation of the benzene core: boat structures have the “stern” amino group strongly donating to the “bow” nitro group in theparaposition and two stronger hydrogen bonds between the substituents on the “side” of the boat, whereas twist‐boat structures have two amino groups strongly interacting with the nitro group in their commonorthoposition to which there are also two strong hydrogen bonds.1d–fundergo conformational exchange on the13C‐NMR time scale at room temperature. Cooling to 220 K allows detection of all carbon signals and shows C1symmetry to be present. AM1 calculations reproduce the distortions of1d–f. Computations on several 2,4,6‐tridonor‐substituted 1,3,5‐trinitrobenzenes indicate that the pronounced deviations from planarity in1a–f

ISSN:0009-2940    

DOI:10.1002/cber.19911240809

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe X‐ray crystallographic analysis of the mono‐, di‐, and tri‐potassium salts2b–dof trinitrophloroglucinol (2a) show their benzene rings to become considerably more distorted on successive deprotonation. A parallel increase in C – C, and a decrease in C – O and C – N bond lengths leading to a radialenetype structure is also observed. For2b, two chemically different molecules are found in the crystal which differ in their hydrogen‐bond pattern as well as in their average bond lengths and deviation of their benzene rings from planarity. AM1 calculations show that for2b,da multitude of structures, differing widely in the deviation of their benzene cores form planarity, can exist within a small energy range (<3 kcal/mol). The experimental and computational results are discussed in terms of a model that emphasizes “push‐pull” interactions as the main cause for the distortions of the benzene rings in

ISSN:0009-2940    

DOI:10.1002/cber.19911240810

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Soluble Bisaxially Substituted (Phthalocyaninato)ruthenium ComplexesSeveral attempts to prepare (tBu4Pc)Ru only led to an impure product (tBu4Pc)RuLx. This reacts quantitatively with pyridine to form (tBu4Pc)Ru(py)2, easily purified by chromatography. In addition the preparation of (tBu4Pc)RuL2with L = pyridine, 2‐picoline (2‐pic), 3‐picoline (3‐pic),4‐picoline (4‐pic), 2,5‐lutidine (2,5‐lut), and 2,6‐lutidine (2,6‐lut), respectively, is described. All complexes are characterized by spectroscopic methods including1H‐NMR spectroscopy. Not even in the cases of (tBu4Pc)RuL2with L = 2‐pic and 2,5‐lut, a careful removal of the ligands L by thermogravimetric methods (TG/DTA) leads to pure (tBu4Pc)Ru. For comparison, the bisadducts PcRuL2with L = pyridine, picolines (2‐pic, 3‐pic, 4‐pic), lutidines (2,3‐lut, 2,5‐lut, 2,6‐lut), and chloropyridines (2‐Clpy and 3‐Clpy), respectively, are prepared by treatment of PcRu with an excess of the ligand. For the first time (phthalocyaninato)iron complexes PcFeL2with sterically hindered axial ligands, e.g. PcFe(2‐pic)2, are prepared and

ISSN:0009-2940    

DOI:10.1002/cber.19911240811

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY