Zur Kristall‐ und MolekülStruktur des Hexaphenyldiplumbans

Abstract

Die Gitterkonstanten des Hexaphenyldiplumbans (Raumgruppe P21/c) wurden neu bestimmt: a = 17,16 ± 0,01, b = 9,410 ± 0,002, c = 21,60 ± 0,015 Å, β = 116,8 ± 0,2°; Z = 4; d (ber.) = 1,87, d25° C (gef.2)) 1,88g · cm−3. Auf Grund der Auswertung von 1800 unabhängigen dreidimensionalen Diffraktometerdaten liegen im kristallinen Hexaphenyldiplumban im Gegensatz zu einer früheren Untersuchung2) nur Molekeln mit einem einheitlichen Pb–Pb‐Bindungsabstand von 2,83 ± 0,01 Å vor.

Trigonal Bipyramidal M2Ch32- (M = Sn, Pb; Ch = S, Se, Te) and TlMTe33- Anions: Multinuclear Magnetic Resonance, Raman Spectroscopic, and Theoretical Studies, and the X-ray Crystal Structures of (2,2,2-crypt-K+)3TlPbTe33-·2en and (2,2,2-crypt-K+)2Pb2Ch32-·0.5en (Ch = S, Se)

“…The apical Pb−Pb distance in Pb 2 S 3 2- [3.1467(7) Å] is shorter than those observed in Pb 2 Se 3 2- [3.2260(8) Å] and Pb 2 Te 3 2- [3.249(2) and 3.232(1) Å]. The Pb−Pb distances of all three chalcogens are significantly longer than the reported single-bond Pb−Pb distances of 2.844(4) Å in Ph 6 Pb 2 and 2.908(1) Å in Ph 3 Pb·Pb[C(SiMe 3 ) 3 ]Ph 2 but are comparable to the intermetallic distances reported for the M 9 clusters [e.g., Pb 9 3- , 3.050(3)−3.627(3) Å; Pb 9 4- , 3.0639(14)−3.4510(13) Å] . The Tl−Pb distance in TlPbTe 3 3- [3.332(2) Å] is significantly longer than the Pb−Pb distance observed in Pb 2 Te 3 2- . , The M−M distances parallel the covalent radii of the chalcogens, increasing in the order S < Se < Te in the tin and lead anion series.…”