Go toArchive
Browse byFacets
Bookbag ( 0 )
'Phosphine' in keywords Facet   Publication Year 2001  [X]
Results  2 Items
Sorted by   
Section
Publication Year
2001[X]
1Author    Gerhard Müller, Hans-Joachim Matheus3, Martin WinklerbRequires cookie*
 Title    Donor-Acceptor Complexes between Simple Phosphines. First Structural Data for an Almost Forgotten Class of Compounds  
 Abstract    Lewis acid-base adducts between simple phosphines have been structurally characterized for the first time in the form of (Me3 P)PBr3 (1) and (MeiPjPB^Bz' (2; Bz' = 3,5-dimethyl-benzyl). On the basis of its solid-state structure the bonding situation in 1 may be described as intermediate between a neutral donor-acceptor complex containing hypervalent phosphorus(III) and an ion pair, according to the resonance formulae Me3 P —► PBn — [Me3 P-PBr2 ]+Br_ . The weak (incomplete) bond formation to the third bromine atom clearly reflects the reluctance of trivalent phosphorus to accommodate more than four electron pairs in its valence shell. (Crystal data for 1: monoclinic P2\ln, a = 7.142(3), b = 16.844(2), c = 8.139(4) A, ß = 106.24(2)°, Z = 4). As a result of the inferior acceptor properties of PB^Bz' as compared to PBr3 , 2 has more ion pair character [MeiP-PBrBz] Br"othan 1. (Crystal data for 2: orthorhombic P 2j 2i2 i, a = 7.063(2), b = 8.578(2)rf c = 25.158(4) A, Z = 4). Both compounds have short P-P bonds (1: 2.264(2); 2: 2.236(2) A). The results are compared with previous IR/Raman and NMR investigations on 1 : 1 and 2 : 1 adducts between organophosphines (as donors) and phosphorus trihalides (as acceptors). 
  Reference    Z. Naturforsch. 56b, 1155—1162 (2001); received July 17 2001 
  Published    2001 
  Keywords    Hypervalence, Phosphines, Lewis Acid-Base Adducts 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1155.pdf 
 Identifier    ZNB-2001-56b-1155 
 Volume    56 
2Author    Gerhard Müller, Jörg Brand, SimoneElisabeth JetterRequires cookie*
 Title    Donor-Acceptor Complexes between Organoamines and Phosphorus Tribromide  
 Abstract    Lewis acid-base adducts between NMe3, tmeda (A^A^Af'-tetramethylethylenediamine), and 1.4-dimethylpiperazine as donors and PBr3 as acceptor have been prepared and structurally characterized. NMe3 and tmeda form 1:1 adducts (Me3 N)PBr3 (1) and (tmeda)PBr3 (2), re­ spectively, while 1,4-dimethylpiperazine adds 2 molecules of PBr3 leading to [(1,4-dimethyl-piperazine)(PBr3):] (3). Adduct 2 is found in two modifications 2a and 2b with different crystal and molecular structures. (Crystal data of 1: monoclinic P2\/n, a = 5.983(3), b = 10.821(2), c = 13.877(5) Ä, ß = 99.70(2)°, Z = 4. 2a: monoclinic P2i/c, a = 7.891(1), b = 12.826(1), c = 12.218(2) A ,ß = 102.162(6)°, Z = 4. 2b: monoclinic P2]/n, a = 11.687(2), b = 8.375(1), c = 12.668(1) A, ß = 102.74(1)°, Z = 4. 3: monoclinic P2Jc, a = 6.383(3), b = 16.36(3), c = 8.407(3) A,ß= 101.49(2)°, Z= 2). The molecular structures of 1 and 2 indicate a partially ionic character with a strongly bonded amine and one (1) or two (2) weakly bonded bromine atoms. In 2 the donor tmeda is bonded through both nitrogen atoms to one phosphorus atom. In 3 the 1.4-dimethylpiperazine ring is in chair conformation, the methyl and PBr3 substituents being in equatorial and axial positions, respectively. Due to axial-axial repulsion the N-P donor-acceptor bonds are long while the P-Br bonds are rather uniform in length. 
  Reference    Z. Naturforsch. 56b, 1163—1171 (2001); received July 17 2001 
  Published    2001 
  Keywords    Hypervalence, Phosphines, Lewis Acid-Base Adducts 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1163.pdf 
 Identifier    ZNB-2001-56b-1163 
 Volume    56