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'nionic Benzylphosphines' in keywords Facet   section ZfN Section B  [X]
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1993 (2)
1Author    Gerhard Müller, Joachim LachmannRequires cookie*
 Title    Sterisch belastete cyclische Phosphanborane Sterically Crowded Cyclic Phosphine-Boranes  
 Abstract    A The anionic phosphine o-(diphenylphosphinomethyl)phenyl L has been used to prepare the sterically crowded cyclic phosphine-boranes BL3, 'BuBL2, and 'Bu2BL by reaction o f the lith-iated ligand LiL with B(OM e)3, 'BuB(OM e)2, and 'Bu2BOMe, respectively. In the new com ­ pounds 'BuBL-, and 'Bu^BL one ligand L is bonded to the boron center by both its carbanionic and its phosptiino function with formation o f five-membered rings. In solution 11B and 31P N M R spectroscopy does not indicate substantial B -P dissociation, i.e., the existence o f three-coordinate boron. The steric bulk o f L in BL3 leads to the formation o f oligom ers in solution, presumably by a bridging coordination mode o f L to two boron centers. N o conclusive evi­ dence as to the monom eric or oligomeric nature o f BL3 in the solid state can be given, however. Five-membered ring form ation is proven for the solid state by X-ray structure determinations o f 'BuBL2 and 'Bu2BL which in addition confirm that the steric bulk o f L is superior to that o f a tert. butyl group. 
  Reference    Z. Naturforsch. 48b, 1248 (1993); eingegangen am 13. Mai 1993 
  Published    1993 
  Keywords    nionic Benzylphosphines, Cyclic Phosphine-Boranes, Crystal Structure, Steric Hindrance 
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 TEI-XML for    default:Reihe_B/48/ZNB-1993-48b-1248.pdf 
 Identifier    ZNB-1993-48b-1248 
 Volume    48 
2Author    Indium Gallium, ThalliumG. Erhard Müller, Joachim LachmannRequires cookie*
 Title    Vier-und fünffach koordinierte Organometall-Phosphankomplexe von Aluminium, Gallium, Indium und Thallium Four-and Five-Coordinate Organom etal Phosphine Complexes of Aluminum  
 Abstract    A The organom etal phosphine complexes M L3 (L = [o-(Ph2PCH2)C6H4]"; M = A l3+, G a3+, In3+) are obtained from MC13 and the lithiated ligand in diethyl ether. Tl[o-(Ph2PC H 2)C6H 4]3 is prepared from T1C1 by a disproportionation reaction. M 1 species could not be detected with L as ligand. Al[o-(Ph2PCH 2)C6H4]3 is the first triorganoaluminum bis(phosphine) adduct where C3P2 pentacoordination at aluminum has been definitely proven for both the solution (<5(27A1) = 131 ppm, w 1/2 = 12 kHz) and the solid state (d (A l-P) = 2.676(3)/2.782(2) Ä). The trigonal-bipyramidal coordination geometry (C3P2) at Al is achieved by two o f the anionic phosphines acting as chelating ligands, spanning equatorial (C atoms) and axial sites (P atom s), while the third phosphine is only carbon-bonded. Like A1L3, the heavier congeners M L3 (M = G a, In, Tl) are stereochemically nonrigid molecules in solution. Surprisingly, in the solid state only InL3 resembles the aluminum complex (C3P2 penta-coordination) while G aL 3 and T1L3 contain four-coordinate metal centers (C3P). This may be rationalized by the notice­ ably less polar G a -P bonds as compared to A l-P and I n -P bonds, while in T1L3 the span o f the ligand is not sufficient to allow for chelating coordination at a five-(or six-)coordinate Tl center. 
  Reference    Z. Naturforsch. 48b, 1544—1554 (1993); eingegangen am 12. Juli 1993 
  Published    1993 
  Keywords    nionic Benzylphosphines, Main Group Metals, Phosphine Complexes, Crystal Structure 
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 TEI-XML for    default:Reihe_B/48/ZNB-1993-48b-1544.pdf 
 Identifier    ZNB-1993-48b-1544 
 Volume    48