Organolead(IV) polymers [(Me3Pb)4M(CN)6·nH2O] with M=Fe and Ru (0≤n≤2): Solid-state NMR and vibrational spectroscopy; Crystal structure of the dihydrates

From aqueous solutions of Me3PbCl and K4[M(CN)6] (4:1; M=Fe or Ru), primarily the diaqua compounds [(Me3Pb)4M(CN)6·2H2O], 4a and 4b, precipitate. These turn out to be not the three-dimensional host-guest systems [{Me3Pb(H2O)2}(Me3Pb) 3M(CN6)], but to consist of infinite, puckered layers whose in-built -M-CN-Pb-OH2 units are likely to form hydrogen bridges between the layers. 4a appears to be sensitive to even very modest influences (including grinding) and tends to lose the coordinated H2O molecules partially or totally. This feature is monitored best by both infrared/Raman and CP MAS solid-state NMR spectroscopy. The strictly anhydrous species, 5a and 5b, strongly resemble their earlier-reported Me3Sn-homologues in also displaying strongly temperature-dependent 13C solid-state NMR spectra, but show no ion-exchange activity. The 13C-, 15N- and 207Pb-NMR data in combination yield detailed information about crystallographic sites and intramolecular mobility ol' the Me3Pb groups.