Evaluation of dispersion type metal···π arene interaction in arylbismuth compounds - an experimental and theoretical study.

The dispersion type Bi···π arene interaction is one of the important structural features in the assembly process of arylbismuth compounds. Several triarylbismuth compounds and polymorphs are discussed and compared based on the analysis of single crystal X-ray diffraction data and computational studies. First, the crystal structures of polymorphs of Ph3Bi (1) are described emphasizing on the description of London dispersion type bismuth···π arene interactions and other van der Waals interactions in the solid state and the effect of it on polymorphism. For comparison we have chosen the substituted arylbismuth compounds (C6H4-CH═CH2-4)3Bi (2), (C6H4-OMe-4)3Bi (3), (C6H3-t-Bu2-3,5)3Bi (4) and (C6H3-t-Bu2-3,5)2BiCl (5). The structural analyses revealed that only two of them show London dispersion type bismuth···π arene interactions. One of them is the styryl derivative 2, for which two polymorphs were isolated. Polymorph 2a crystallizes in the orthorhombic space group P212121, while polymorph 2b exhibits the monoclinic space group P21/c. The general structure of 2a is similar to the monoclinic C2/c modification of Ph3Bi (1a), which leads to the formation of zig-zag Bi-arenecentroid ribbons formed as a result of bismuth···π arene interactions and π···π intermolecular contacts. In the crystal structures of the polymorph 2b as well as for 4 bismuth···π arene interactions are not observed, but both compounds revealed C-HPh···π intermolecular contacts, as likewise observed in all of the three described polymorphs of Ph3Bi. For compound 3 intermolecular contacts as a result of coordination of the methoxy group to neighboring bismuth atoms are observed overruling Bi···π arene contacts. Compound 5 shows a combination of donor acceptor Bi···Cl and Bi···π arene interactions, resulting in an intermolecular pincer-type coordination at the bismuth atom. A detailed analysis of three polymorphs of Ph3Bi (1), which were chosen as model systems, at the DFT-D level of theory supported by DLPNO-CCSD(T) calculations reveals how van der Waals interactions between different structural features balance in order to stabilize molecular arrangements present in the crystal structure. Furthermore, the computational results allow to group this class of compounds into the range of heavy main group element compounds which have been characterized as dispersion energy donors in previous work.

Iron-bismuth halido compounds: molecules, clusters, and polymers.

The pentamethylcyclopentadienyl substituted iron-bismuth halides [Bi{FeCp*(CO)2}X2] [X = Cl (1), Br (2), I (3); Cp* = η(5)-C5Me5] were synthesized starting from [FeCp*(CO)2]2 and BiX3 (X = Cl, Br), followed by halogen exchange reaction with KI in case of 3. From a reaction mixture of [FeCp*(CO)2]2 with BiCl3 in CH2Cl2 to which CH3CN had been added, a novel coordination polymer of the formula [FeCp*(CO)2(CH3CN)]2n[Bi4Cl14]n (4) was isolated. The change of the molar ratio from 1:1 to 1:2 in the reaction of [FeCp*(CO)2]2 with BiBr3 afforded the novel ionic complex [{FeCp*(CO)2Br]2[Bi6Br22{FeCp*(CO)2}]·CH2Cl2 (5·CH2Cl2). It is demonstrated that treatment of [FeCp*(CO)2X] (X = Cl, Br) with BiCl3 and BiBr3, respectively, is a more convenient route to synthesize the new halido bismuthates 4 and 5.

Spirocyclic tin salicyl alcoholates - a combined experimental and theoretical study on their structures, 119Sn NMR chemical shifts and reactivity in thermally induced twin polymerization.

The spirocyclic tin salicyl alcoholate, 4H,4'H-2,2'-spirobi[benzo[d][1,3,2]dioxastannine] (1), and its 6,6'-dimethoxy (2) and 8,8'-di-tert-butyl-6,6'-dimethyl derivative (3) were synthesized and thermally induced twin polymerization of precursor 2 was performed to give a SnO2-containing hybrid material. Studies on the molecular structures of 1-3 were carried out using 119Sn{1H} CP MAS NMR spectroscopy and DFT calculations. Crystallization of compound 3 from dimethyl sulfoxide solution provided the Lewis acid-base adduct 3(dmso)2 exhibiting a hexacoordinated tin atom in the solid state, in agreement with the results of the spectroscopic and DFT calculation data. 119Sn NMR spectroscopy of the compounds 1-3 and 3(dmso)2 revealed equilibria among the diverse oligomers in solution phase pointing at hexacoordinated tin atoms.

Organoantimony(III) compounds containing (imino)aryl ligands of the type 2-(RN=CH)C6H4 (R = 2',4',6'-Me3C6H2, 2',6'-(i)Pr2C6H3): bromides and chalcogenides.

The reaction of 2-(RN=CH)C(6)H(4)MgBr [R = 2',4',6'-Me(3)C(6)H(2) (R(1)), 2',6'-(i)Pr(2)C(6)H(3) (R(2))] [prepared from 2-(R(1)N=CH)C(6)H(4)Br (1) or 2-(R(2)N=CH)C(6)H(4)Br (2) and Mg] with SbCl(3) in a 2 : 1 and 1 : 1 molar ratio followed by treatment with an aqueous KBr solution gave [2-(R(1)N=CH)C(6)H(4)](2)SbBr (3) and [2-(R(2)N=CH)C(6)H(4)](2)SbBr (4) as well as [2-(R(1)N=CH)C(6)H(4)]SbBr(2) (6) and [2-(R(2)N=CH)C(6)H(4)]SbBr(2) (7). Treatment of 4 with Na(2)S·9H(2)O provided the dinuclear [{2-(R(2)N=CH)C(6)H(4)}(2)Sb](2)S (5). Heterocyclic species, i.e. the oxide cyclo-[{2-(R(2)N=CH)C(6)H(4)}SbO](3) (8) and the sulfides cyclo-[{2-(R(1)N=CH)C(6)H(4)}SbS](2) (9) and cyclo-[{2-(R(2)N=CH)C(6)H(4)}SbS](2) (10), were obtained by reacting dibromides 6 and 7 with KOH and Na(2)S·9H(2)O, respectively, in a water-toluene solvent mixture. The sulfide 10 reacted with [W(CO)(5)(thf)] to yield the heterometallic complex cyclo-[{2-(R(2)N=CH)C(6)H(4)}SbS](2)[W(CO)(5)] (11). The compounds were characterised by multinuclear NMR spectroscopy in solution, mass spectrometry and IR spectroscopy in the solid state. The molecular structures of 4, 5, 6·CHCl(3), 7, 9·CH(2)Cl(2), 10 and 11·0.25CH(3)OH were established by single-crystal X-ray diffraction. Theoretical calculations using DFT methods were carried out on bromide 7 and the geometrical isomers of its dimer association as well as the geometrical isomers of sulfide 10 and its monomer.