Rokuro Okawara

Studies on dialkyltin diacetate derivatives

Abstract A series of dialkyltin diacetates and their derivatives, R 2 Sn(OAc) 2 , [(AcO)R 2 Sn] 2 O and (AcO)R 2 SnOSnR 2 (OH) (RCH 3 , C 2 H 5 , n-C 3 H 7 , n-C 4 H 9 ), have been prepared. Dialkyltin diacetates are monomeric in benzene,having a nonsymmetrically chelated octahedral configuration; bridging of acetoxy groups seems to occur in the neat liquid or in the crystalline state. The compounds [AcO)R 2 Sn] 2 O are dimeric at moderate concentrations and dissociate to monomers in dilute benzene and chloroform solutions. This change is reflected in changes of the CO 2 and SnO infrared bands. The dimeric methyl compound showed two tin-methyl proton chemical shifts with a small difference. Molecular weight of (AcO)(C 4 H 9 ) 2 SnOSn(C 4 H 9 ) 2 (OH) increases with concentration from that of dimer. This seems to be caused by the bridging of the acetoxy groups among dimers.

Synthesis and configurations of organotin oxinates

Abstract A series of organotin of the general type R3SnOx, R2SnXOx and RSnClOx2 (R = CH3, C2H5, n-C3H7, n-C4H9 and C6H5; X = Cl and NCS; Ox = C9H6NO) has been synthesized. Studies of the ultraviolet spectra indicate that these compounds involve bidentate oxinato ligands and therfore R3SnOx and R2SnXOx contain pentavalent tin atoms. The order of the stability is also suggested by the ultraviolet spectra. An interesting dispropotion reaction is described in which the coordination number of the tin atom changes from five to six. The configurations of the organotin oxinates have been deduced from their NMR and infrared spectra.

Preparation and properties of dimeric tetra-alkyldistannoxane derivatives: XR2SnOSnR2OH and XR2SnOSnR2OR′

Abstract Distannoxane derivatives of types XR2SnOSnR2OH and XR2SnOSnR2OR′ were mainly prepared from XR2SnOSnR2X. The preparation and properties of nineteen compounds, of which nine are new compounds, are described. These compounds were found to be dimeric in solution. Dimerization of these distannoxanes results by the pairing of two SnOSn bonds to form a four-membered ring, in which two kinds of tin atoms, tetra- and penta-coordinated, are involved. In the two types of derivatives discussed, it is suggested that an additional intramolecular coordination within the dimer or intermolecular coordination in the solid from each oxygen atom of the OH or OR′ group to each tetra-coordinated tin atom is possible. In this way we have all tin atoms penta-coordinated, and we can interpret the peculiar stability of the SnOH toward condensation and the absence of isomers in these derivatives.

Organometal complexes I. Diorganotin bis(s-hydroxyquinolinates), diorganotin-(2,2′-bipyridyl) (1,10-phenanthroline) dichlorides A029 V 3

Abstract By the reaction of dialkyl- and diphenyltin dichlorides with the bidentate ligands, S-hydroxyquinoline, 2,2′-bipyridyl and 1,10-phenanthroline, a series of diorganotin complexes were prepared. From molecular weight determinations, and measurement of infrared and ultraviolet spectra of these complexes, the following results were obtained. (1) Diorganotin bis(S-hydroxyquinolinates) are monomeric in benzene solution and their stability possibly is comparable with that of transition-metal S-hydroxyquinolinates. (2) Di- n -butyltin(2,2′-bipyridyl) dichloride dissociates to a considerable extent in solution. (3) All of these organotin complexes contain six-coordinated tin atoms.

Infra-red and PMR spectra of some organotin(IV) N,N-dimethyldithiocarbamates

Abstract Several types of tin(IV) N,N-dimethyldithiocarbamato complexes, Cl2Sn(SSCN Me2)2, Me2Sn(SSCN Me2)2, MeXSn(SSCN Me2)2 (X=Cl, Br, I), and Me2SnX(SSCN Me2) (X=Cl, Br, I) have been prepared. Infra-red and PMR spectra of these complexes have been measured. The results suggest the chelation of dithiocarbamato group. An octahedral trans-configuration have been proposed for Me2Sn(SSCN Me2)2. Configuration of penta-co-ordinated Me2SnX(SSCN Me2) have also been discussed.

Structural Aspects of Organotin Compounds

Publisher Summary This article reviews the structures of those organotin compounds that possess a tin atom having an essential valency of four but having coordination greater than four. Advances in the structural chemistry of organotin compounds occupy a prominent position among recent developments in the field of organometallic chemistry. Another structural aspect of organotin chemistry is associated with the elucidation of the marked differences in chemical and physical properties of the polymeric diorganotin oxides in contrast to the corresponding diorganopolysiloxanes. Diorganotin oxides are usually insoluble, amorphous, and infusible materials, whereas polymeric diorganopolysiloxanes are viscous liquids, soluble in many organic solvents. Although the polymeric oxides are amorphous in appearance, X-ray powder photographs indicate a fairly ordered intermolecular arrangement . There is no doubt that the distannoxane ring would be present in these polymeric oxides. However, such an oxide could contain only pentacoordinated or both tetra- and pentacoordinated tin.

The infrared and far infrared spectra of trialkyltin formates: presence of a linear polymer in the solid state and in solution

Triethyltin and tri-n-propyltin formate were found to exist as low polymers in organic solvents. In the infrared spectra of these compounds in the solid state, the formoxy group shows bands similar to those of the formate anion at near 1590 cm−1, 1360 cm−1 and 770 cm−1; furthermore a band which is due to a weak coordination of the oxygen atom with the tin atom is found near 300 cm−1. The absorption due to the SnC stretching vibration appears only at 520 cm−1 in triethyltin formate. In the spectra of solutions, additional new bands due to the terminal formoxy group appear at near 1660 cm−1, 1245 cm−1 and 430 cm−1. From these facts it is concluded that in the solid state trialkyltin formate is a linear polymer in which the planar SnC3e group is bridged by the -OCO- unit, and that even in solution this structure is partially maintaine.

Preparation and properties of monoalkylthallium derivatives

Abstract Several monomethyl- and monoethylthallium derivatives have been synthesized for the first time. Methylthallium dicarboxylates are found to decompose when heated or treated with halide anions to give thallous ion and methyl esters of carboxylic acids, methanol or methyl halides. From the structural studies on RTl(Ox)2 and RTl(OOCC3H7-iso)2 (R = CH3 and C2H5) in solution, it is suggested that these compounds have penta-coordinated thallium atoms.

The infrared study of trimethylantimony(V) derivatives containing Sb-O bonds

Some trimethyl-substituted antimony(V) compounds containing Sb-O bonds such as trimethylantimony dicarboxylates, dinitrate or oxybis(trimethylantimony) dinitrate, were prepared. From the infrared spectroscopic investigation, both in the solid and in solution, and cryoscopic molecular weight determinations in benzene, the following results were obtained. (1) (CH3)3SbX2 (where X is OCOR or NO3) has a trigonal bipyramidal configuration with the C3Sb group in the same plane and X at the apices. (2) The Sb-O bond in (CH3)3SbX2 (where X is OCOR or NO3) is covalent in nature while the Sb-O bond in oxybis(trimethylantimony) dinitrate is intermediate in character between covalent and ionic bonds.

Occurrence of dimeric trimethyltin hydroxide

Abstract The infrared spectra of trimethyltin hydroxide are examined in the solid state and in solution. These spectra are discussed in terms of a weak coordination of the oxygen atom with the tin atom. Ebulliometric molecular weight determinations of trimethyltin hydroxide in carbon tetrachloride, chloroform or benzene solution indicate a dimeric molecule [(CH 3 ) 3 SnOH] 2 . The SnO stretching vibration band in solid trimethyltin hydroxide is observed at 370 cm −1 , while in carbon tetrachloride solution it is found in the 500–580 cm −1 region. The OH stretching vibration band which is observed at 3620 cm −1 in the solid shifts to 3658 cm −1 in solution. Only one SnC stretching vibration band is observed at 540 cm −1 in the solid state, while in solution an additional absorption associated with the SnC stretching vibration is observed. These facts suggest that in the solid state trimethyltin hydroxide is a linear polymer in which the planar (CH 3 ) 3 Sn group is bridged by the -O(H)- unit, whereas in solution it has a dimeric structure, in which two SnO groups form a four-membered ring.