ISSN:
0044-2313
Keywords:
Chloro Pyridine Rhenates(III)
;
Bromo Pyridine Rhenates(III)
;
Crystal Structure
;
trans Influence
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Preparation of Halogeno Pyridine Rhenates(III), [ReX6-n(Py)n](3-n)- (X = Br, Cl; n = 1-3) Crystal Structures of trans-[(C4H9)4N][ReBr4(Py)2], mer-[ReCl3(Py)3], and mer- [ReBr3(Py)3]The mixed halogeno-pyridine-rhenates(III), [ReX6-n(Py)n](3-n)- (X = Br, Cl), n = 1-3, have been prepared for the first time by reaction of the tetrabutylammoniumsalts (TBA)2[ReX6] (X = Br, Cl) in pyridine with (TBA)BH4 and separation by chromatography on Al2O3. Apart from the monopyridine complexes only the trans and mer isomers are formed from the bis-and tris-pyridine compounds. The X-ray structure determinations of the isotypic neutral complexes mer- [ReX3(Py)3] (monoclinic, space group P 21/n, Z = 4; for X = Cl: a = 9,1120(8), b = 12,5156(14), c = 15,6100(13) Å, β = 91,385(7)°; for X = Br: a = 9,152(5), b = 12,852(13), c = 15,669(2) Å, β = 90,43(2)°) reveal, due to the stronger trans influence of pyridine compared with Cl and Br, that the Re—X distances in asymmetric Py—Re—X3 axes with ReCl3 = 2,397 Å and ReBr3 = 2,534 Å are elongated by 1,3 and 1% in comparison with symmetric X1—Re—X2 axes with ReCl1 = ReCl2 = 2,367 Å and ReBr1 = 2,513 and ReBr2 = 2,506 Å, respectively. The Re—N bond lengths are roughly equal with 2,12 Å. Trans-(TBA)[ReBr4(Py)2] crystallizes triclinic, space group P1, a = 9,2048(12), b = 12,0792(11), c = 15,525(2) Å, α = 95,239(10), β = 94,193(11), γ = 106,153(9)°, Z = 2. The unit cell contains two independent but very similar complex anions with approximate D2h(mmm) point symmetry.
Notes:
Die gemischten Halogeno-Pyridin-Rhenate(III), [ReX6-n(Py)n](3-n)- (X = Br, Cl), n = 1-3, werden durch Umsetzung der Tetrabutylammoniumsalze (TBA)2[ReX6] (X = Br, Cl) in Pyridin mit (TBA)BH4 und chromatographische Trennung an Al2O3 erstmalig dargestellt. Neben den Mono-Pyridin-Komplexen entstehen von den Bis-und Tris-Pyridin-Verbindungen nur die trans- und mer-Isomeren. Die Röntgenstrukturukturanalysen der isotypen Neutralkomplexe mer-[ReX3(Py)3] (monoklin, Raumgruppe P 21/n, Z = 4; für X = Cl: a = 9,1120(8), b = 12,5156(14), c = 15,6100(13) Å, β = 91,385(7)°; für X = Br: a = 9,152(5), b = 12,852(13), c = 15,669(2) Å, β = 90,43(2)°) zeigen, daß als Folge des größeren trans-Einflusses des Pyridins im Vergleich zu Cl und Br, die Re—X-Bindungslängen in der unsymmetrisch besetzten Py—Re—X3-Oktaederachse mit ReCl3 = 2,397 Å und ReBr3 = 2,534 Å um 1,3 bzw. 1% größer sind als in der symmetrischen Achse X1—Re—X2 mit ReCl1 = ReCl2 = 2,367 Å und ReBr1 = 2,513 und ReBr2 = 2,506 Å. Die Re—N-Abstände sind dagegen mit etwa 2,12 Å annähernd gleich. Trans-(TBA)[ReBr4(Py)2] kristallisiert triklin, Raumgruppe P1, a = 9,2048(12), b = 12,0792(11), c = 15,525(2) Å, α = 95,239(10), β = 94,193(11), γ = 106,153(9)°, Z = 2. Die Elementarzelle enthält zwei kristallographisch verschiedene, aber sehr ähnliche Komplexanionen mit annähernd D2h(mmm)-Punktsymmetrie.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/zaac.19966220203
