TY - JOUR
T1 - Mehrfachbindungen zwischen hauptgruppenelementen und übergangsmetallen. IX. Tellur-brücken in organometall-komplexen
T2 - Aufbau, protonierung und molekülgeometrie
AU - A. Herrmann, Wolfgang
AU - Rohrmann, Jürgen
AU - Ziegler, Manfred L.
AU - Zahn, Thomas
PY - 1984/9/25
Y1 - 1984/9/25
N2 - Ligand-free tellurium acts as a bridging element in the novel chromium, molybdenum, and tungsten complexes of composition (μ-Te)[(η5-C5R5)M(CO)3]2 (2a-2e; R = H, CH3; M = Cr, Mo, W) which are accessible in 32-72% isolated yield on treatment of the ionic precursor species Na+(K+) [(η5-C5R5)M(CO)3]- (1a-1e) with potassium tellurite in the presence of hydrochloric acid. The new compounds have been structurally characterized (X-ray diffraction, compound 2a) and exhibit bent metal-tellurium-metal frameworks (e.g. {A figure is presented} Cr,Te,Cr 117.2(0)°). The comparably long chromium-tellurium distances recorded in the case of 2a (279.9(1), 281.4(1) pm) are interpreted as single bonds, thus being in agreement with the electronic requirements of the chromium centres. The tellurium bridge is considered to act as a two-electron ligand which stabilizes two (η-C5H5)Cr(CO)3 fragments. Neither under thermal conditions nor upon photolysis do complexes 2a-2e undergo partial decarbonylation. Hence, they do not represent suitable precursors of the hitherto unknown derivatives of composition (μ-Te)[(η5-C5R5)M(CO)2]2; these latter compounds should contain linear {A figure is presented} multiple-bonded structures like those established for the stoichiometrically analogous sulfur and selenium derivatives. Protonation of 2a with ethereal tetrafluoroboric acid quantitatively yields the Brønsted-acidic ionic complex 3a of formula [(μ-TeH){(η-C5H5)Cr(CO)3}2][BF4]. which can be deprotonated by diethylamine in reverse to its formation.
AB - Ligand-free tellurium acts as a bridging element in the novel chromium, molybdenum, and tungsten complexes of composition (μ-Te)[(η5-C5R5)M(CO)3]2 (2a-2e; R = H, CH3; M = Cr, Mo, W) which are accessible in 32-72% isolated yield on treatment of the ionic precursor species Na+(K+) [(η5-C5R5)M(CO)3]- (1a-1e) with potassium tellurite in the presence of hydrochloric acid. The new compounds have been structurally characterized (X-ray diffraction, compound 2a) and exhibit bent metal-tellurium-metal frameworks (e.g. {A figure is presented} Cr,Te,Cr 117.2(0)°). The comparably long chromium-tellurium distances recorded in the case of 2a (279.9(1), 281.4(1) pm) are interpreted as single bonds, thus being in agreement with the electronic requirements of the chromium centres. The tellurium bridge is considered to act as a two-electron ligand which stabilizes two (η-C5H5)Cr(CO)3 fragments. Neither under thermal conditions nor upon photolysis do complexes 2a-2e undergo partial decarbonylation. Hence, they do not represent suitable precursors of the hitherto unknown derivatives of composition (μ-Te)[(η5-C5R5)M(CO)2]2; these latter compounds should contain linear {A figure is presented} multiple-bonded structures like those established for the stoichiometrically analogous sulfur and selenium derivatives. Protonation of 2a with ethereal tetrafluoroboric acid quantitatively yields the Brønsted-acidic ionic complex 3a of formula [(μ-TeH){(η-C5H5)Cr(CO)3}2][BF4]. which can be deprotonated by diethylamine in reverse to its formation.
UR - https://www.scopus.com/pages/publications/0039321388
U2 - 10.1016/0022-328X(84)80526-4
DO - 10.1016/0022-328X(84)80526-4
M3 - Artikel
AN - SCOPUS:0039321388
SN - 0022-328X
VL - 273
SP - 221
EP - 232
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
IS - 2
ER -