Synthesis and Structure of Organotin(IV) Complexes of Maltol

Abstract

A series of organotin(1V) maltol complexes R4 -,SnL, (1 -4, 6; x = 1-3) and the dichloro-compound C12SnL2 (5) have been prepared and characterized on the basis of their IR-, IH-, 13C-and l%n-NMR data, While an X-ray crystal structure analysis of PhzSnLz (4) and C12SnL2 (5) reveals distorted cis-octahedral structures, the Me2SnL2 molecule (2) adopts a skew-trapezoidal bipyramidal configuration with a very significant difference in the Sn-O(keto) bond distances. The tris-maltol complex BuSnL, (6) exhibits a distorted pentagonal-bipyramidal geometry with the butyl carbon and a hydroxy oxygen constituting the axial orientations. In view of the rapidly developing field of tin compounds in biological chemistry['], we report in this paper on investigations of the coordination of maltol with organotin(1V) compounds including X-ray crystal and molecular structures of R2SnL2 [R = Ph (4), Me (2)], BuSnL, (6), and C12SnL2 (5). The presence of almost discrete carbonyl and hydroxy groups in the ligand allows us to distinguish a dative bond from the normal covalent bond in reference to the group-14 element tin as suggested recently by Haaland[l01. Results and DiscussionThe complexes 1, 2, and 3 were prepared by reaction of the corresponding organotin chloride with the sodium salt of maltol, NaL, as described in eq. (1). If triphenyltin chloride was allowed to react with maltol in the presence of sodium acetate, cleavage of a tin-carbon bond occurred besides the substitution of its C1 atom furnishing only diphenyltin bis(malto1ate) (4). Similarly, the reaction according to eq. (3) yielded C12SnL2 (5). BuSnL3 (6) was obtained from butylstannoic acid and maltol as shown in eq. (4). The tetramaltolatostannane, SnL4, could not be isolated from the reaction of SnCI4 with 4 equivalents of NaL. All these complexes (Table 1)

Tin Organometallic Compounds: Classification and Analysis of Crystallographic and Structural Data: Part 1. Monomeric Derivatives

“…None have seven monodentate ligands, but one example [728] has five monodentate plus a bidentate ligand, another [745] has four monodentate and one tridentate ligands. Other examples have three bidentate and one monodentate ligands [190,542,720,[721][722][723][724][739][740][741], two bidentate plus three monodentate [725][726][727][729][730][731][732]735,736,748] and two monodentate plus one pentadentate [733,734,737,[742][743][744]746,747], 118 Brought …”

Molecular structure of diphenylbis(9,10-phenanthrenesemiquinonate)tin(iv), an organometallic diradical complex

“…Thus, the corresponding C-O and C-C distances in 1 [mean 1.291(6) and 1.44(1) Å] characterise it unequivocally as a semiquinone complex of tin(iv). The Sn-C distances in 1 (2.16 Å) are essentially equal and within the range 8 and R = Ph, O-O = maltolate (5). 8 On the other hand, Sn-O bonds formed by each semiquinone ligand show considerable non-equivalence (D) in length.…”

“…The Sn-C distances in 1 (2.16 Å) are essentially equal and within the range 8 and R = Ph, O-O = maltolate (5). 8 On the other hand, Sn-O bonds formed by each semiquinone ligand show considerable non-equivalence (D) in length. Formally, such a ligand forms one covalent and one dative bond, and their unequal contribution can explain this difference.…”

Trans–cis octahedral interconversion pathway in diorganotin compounds

“…Also, in the cis structures the Os atoms are now opposite to C atoms and form Sn-O bonds shorter than Sn-Op which are now trans to each other, see triangle and cross points for C-Sn-C lower than 115°. From this set we see that trans-dimethyl-bis(3-hydroxy-2-methyl-4H-pyran-4-onato)-tin(IV) (refcode YIBWUB) [26] and cis-diphenyl-bis(3-hydroxy-2-methyl-4H-pyran-4-onato)-tin(IV) (refcode YIBXAI) [26] X-ray structures confirm the trend shown by trans-di-t-butyl-bis(2-picolinato-N,O)-tin (YORLIA) and cis-diphenyl-bis(2-picolinato)-tin (HATKOC), that is, in the trans to cis pathway Os and Os 0 end up cis to each other whereas Op and Op 0 end up trans to each other (Figs. 30-33).…”

“…X-ray structure of trans-dimethyl-bis(3-hydroxy-2-methyl-4H-pyran-4-onato)-tin(IV)[26]. Atoms that do not change position in the trans-cis pathway are shown as balls; all others as capped stick; H atoms are omitted.…”