Organometallic Tin Compounds Derived from 2‐Benzimidazole Propionic Acid

Abstract

Reactions of 2‐benzimidazole propionic acid (1) with [Sn(nBu)3]2O and SnPh3OH gave mononuclear organometallic tin esters 2 and 3, respectively, where 1 is coordinated to the tin atom through the carboxylate group. Further reactions of 2 with DMSO and 3 with methanol, ethanol, pyridine, DMSO, THF and water afforded the corresponding tin compounds coordinated by the base 4–10, respectively. X‐ray diffraction analyses of 5, 6 and 10 were obtained. The solid‐state structures showed that the ligand 1 is bound through both oxygen atoms of the carboxylic group with the Lewis base anti to it. Reaction of 1 with di‐n‐butyltin oxide produced a tetranuclear distannoxane (11) by the association of four Sn(nBu)2 groups, two oxygen atoms and four ligands. Four of the oxygen atoms are tricoordinate. The tin atoms are hexacoordinate with distorted octahedral geometries. The macromolecule has in total seven fused rings. Five of them are four membered rings arranged in a ladder‐type arrangement and the other two are six membered rings. The aliphatic chains and the benzimidazole groups are perpendicularly oriented to the polycyclic arrangement giving a sandwich with polar bonds in the middle and covered by the aliphatic and aromatic groups. In all compounds the ligands showed a chiral helicoidal preferred conformation.

Vapochromic Luminescent π‐Conjugated Systems with Reversible Coordination‐Number Control of Hypervalent Tin(IV)‐Fused Azobenzene Complexes

“…[55] Interestingly, the large upfield shifts in the 119 Sn NMR spectra were observed in DMSO-d 6 (À 467.3 ppm for TAz-H, À 471.1 ppm for TAz-F, À 465.0 ppm for TAz-OBu and À 475.9 ppm for TAz-CF3, Figure S2), strongly suggesting that the DMSO coordination should proceed at the tin atom followed by the formation of the six coordinated state. [56][57][58][59] This result also means that the asymmetric five-and six-coordinated structures can be obtained by selecting the solvent between CDCl 3 and DMSO-d 6 , respectively. Noted that the complexes involving six-coordinated states showed high stability.…”

Organostannoxane-supported nucleobase arrays: synthesis and supramolecular structures of polymeric and molecular organotin complexes containing guanine, uracil and 2-aminopurine

“…The reactions of triorganotin oxides/hydroxides/halides with carboxylic acid are known to form either a carboxylate-bridged coordination polymer or a carboxylate-chelated mononuclear complex (Chart 1). 44,45 It must be mentioned here that in some cases solvent molecule coordination to the tin center stops the polymer formation and leads to the monomer formation (Chart 1). Also in some instances, Sn-C bond cleavage leads to the different product formations in these reactions.…”