One-dimensional iodine-rich iodobismuthates­(III), Cat3{[Bi2I9]­(I2)3} [Cat = 1,4-MePy (1) and 1-EtBMAP (2)], feature the highest amount of “trapped” diiodine units in polyhalogen–halometalates of p-block elements. Both complexes have narrow optical band gaps (1.55 and 1.63 eV, respectively) and moderate thermal stability.

Supramolecular derivatives of chlorostannate(IV) and -plumbate(IV) with {Cl 2 } units, Cat 2 {[MCl 6 ](Cl 2 ) x } (1−5; M = Sn, Pb, cat = 1-methylpyridinium (1-MePy), tetramethylammonium (TMA)) were prepared and characterized by X-ray diffractometry and Raman spectroscopy. In particular, the TMA-containing complexes demonstrate remarkable thermal stability, releasing Cl 2 only at elevated temperatures.

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Reaction of SeO 2 , tetramethylammonium (TMA) chloride, aqueous HCl and Cl 2 yields oxochloroselenate with incorporated Cl 2 units, TMA 3 {[Se 2 O 2 Cl 7 ](Cl 2 )}. The main feature of this compound is the strong (up to 3.5 kcal mol À 1 , according to DFT calculations) Cl•••Cl bonding, which is also detected by Raman spectroscopy.Ability of halide complexes (hetero-or, more commonly, homoleptic) to form inclusion compounds with di-or polyhalogens was noticed decades ago. [1][2][3] Surprisingly, this feature was not systematically studied for years (probably with the only exception -in 1960s and 1970s, Jacobson et al. presented [4][5][6][7] numerous examples of bromoantimonates with {Br 2 } or (Br 3 ) À units incorporated in solid state, as followed from XRD data). After a long pause, this area experiences revival nowadays (it can be related to, on one hand, development of chemistry of polyhalogens [8][9][10] itself [11][12][13][14][15][16][17][18][19][20] and, on another, increasing attention on halogen bonding [21,22] ). In last years, it was shown that formation of "polyhalogenhalometalates" is possible for numerous elements, such as Bi, [23][24][25] Cu, [26] Sn, [27] Pt, [28] Zn, [29] Te [30][31][32] etc. Most of these compounds contain polyiodides (these compounds are of interest due to their lower optical band gaps, [23,24] assuming their potential applicability in photovoltaics) or, less commonly, -bromides; meanwhile, complexes with "trapped" {Cl 2 } are yet very rare. The earlier single report describing Cat 2 {[MCl 6 ](Cl 2 )] (M=Sn IV and Pd IV[2] remained generally overlooked; very recently, we showed [33] that such complexes can be also prepared for Te IV[33] and Pb IV , [34] demonstrating unusually high thermal stability in the case of cat = TMA + .Despite it can be seen now that dichloro-chlorometalates can be prepared for, at least, four elements (Sn, [2,34] Te, [33] Pb [34] and Pd [2] ), their structural chemistry is yet not rich: all known structures are based on [M IV Cl 6 ] 2À building blocks which are