- Diorganotin(IV) derivatives of dipeptides containing at least one essential amino acid residue: Synthesis, characteristic spectral data, cardiovascular, and anti-inflammatory activities
-
New diphenyltin(IV) derivatives of the formula Ph2SnL, where L is the dianion of glycyltryptophan (Gly-Trp), glycylphenylalanine (Gly-Phe), valylvaline (Val-Val), alanylvaline (Ala-Val), and leucylalanine (Leu-Ala), have been synthesized by the reaction of Ph2SnCl2 and the disodium salt of the respective dipeptides. The bonding and coordination behaviour in these derivatives are discussed on the basis of IR, multinuclear 1H, 13C, and 119Sn NMR and 119Sn Moessbauer spectroscopic studies. These investigations suggest that all the dipeptides in Ph2SnL act as dianionic tridentate ligands coordinating through the COO-, NH2, and Npeptide groups. The 119Sn Moessbauer studies, together with the NMR data, suggest a trigonal-bipyramidal geometry around tin in Ph2SnL with the phenyl groups and Npeptide in the equatorial positions, whereas a carboxylic oxygen and the amino nitrogen atom occupy the axial positions. The anti-inflammatory and cardiovascular activities, and toxicity of all the synthesized diphenyltin(IV) derivatives of dipeptides and of n-dibutyltin(IV) derivatives of dipeptides (synthesized and characterized earlier) viz. Gly-Trp, Val-Val, Ala-Val, glycyltyrosine (Gly-Tyr), leucyltyrosine (Leu-Tyr), and leucylleucine (Leu-Leu) are discussed. The n-dibutyltin(IV) derivatives exhibit better cardiovascular and anti-inflammatory activities than the diphenyltin(IV) analogues.
- Nath, Mala,Pokharia, Sandeep,Eng, George,Song, Xueqing,Kumar, Ashok
-
-
Read Online
- An unusual reaction of (β-dimethylaminoethoxy)triethyltin with phenyltin trichloride. The first X-ray structural evidence of the existence of complexes R2SnXY·R2SnXY (R = Alkyl, Aryl; X, Y = Hal, OR, X ≠ Y) both as unsymmetrical addu
-
The substituent exchange reaction of PhSnCl3 with [Et 3Sn-(OCH2CH2NMe2)] gives rise unexpectedly to the unsymmetrical adduct [Ph2SnCl2· Ph2Sn(OCH2CH2/
- Portnyagin, Ivan A.,Nechaev, Mikhail S.,Khrustalev, Victor N.,Zemlyansky, Nikolay N.,Borisova, Irina V.,Antipin, Mikhail Yu.,Ustynyuk, Yuri A.,Lunin, Valery V.
-
-
Read Online
- -
-
Solutions of triphenyl tin hydroxide (resp. hexaphenyl distannoxane) in benzene can be used for the extraction of numerous inorganic and organic anions out of slightly acid aqueous solutions. Several separations will be possible.
- Bock, Rudolf,Niederauer, Heinz-Theo,Behrends, Karl
-
-
Read Online
- Direct Detection, Dimerization, and Chemical Trapping of Dimethyl- and Diphenylstannylene from Photolysis of Stannacyclopent-3-enes in Solution
-
Dimethyl- and diphenylstannylene (SnMe2 and SnPh2, respectively) have been successfully detected and characterized in solution. The stannylenes were generated by photolysis of 1,1,3-trimethyl-4-phenyl- (2) and 3,4-dimethyl-1,1-diphenylstannacyclopent-3-ene (3), respectively, which have been shown to extrude the species cleanly and in high (0.6 2SnCl2) as the stannylene substrate. Laser flash photolysis of 2 and 3 in deoxygenated hexanes affords promptly formed transient absorptions assigned to SnMe2 (λmax = 500 nm; ε500 = 1800 ± 600 M-1 cm-1) and SnPh2 (λmax = 290, 505 nm; ε500 = 2500 ± 600 M-1 cm-1), respectively, which decay with absolute second-order rate constants within a factor of 2 of the diffusional limit in both cases. The decay of the stannylenes is accompanied by the growth of new transient absorptions ascribable to the corresponding dimers, the structures of which are assigned with the aid of DFT and time-dependent (TD) DFT calculations at the (TD)ωB97XD/6-31+G(d,p)C,H,O-LANL2DZdpSn level of theory. Dimerization of SnMe2 affords a species exhibiting λmax = 465 nm, which is assigned to the expected Sn=Sn doubly bonded dimer, tetramethyldistannene (Me2Sn=SnMe2, 16a), in agreement with earlier work. In contrast, the spectrum of the dimer formed from SnPh2 exhibits strong absorptions in the 280-380 nm range and a very weak absorption at 650 nm, on the basis of which it is assigned to phenyl(triphenylstannyl)stannylene (17b). The calculations suggest that 17b is formed via ultrafast rearrangement of a novel phenyl-bridged stannylidenestannylene intermediate (20), which can be formed either directly by "endo" dimerization of SnPh2 or by isomerization of the "exo" dimer, tetraphenyldistannene (16b); the predicted barriers for these rearrangements are consistent with the experimental finding that the observed product is formed at close to the diffusion-controlled rate. Absolute rate and equilibrium constants are reported for the reactions of SnMe2 and SnPh2 with Me2SnCl2 and methanol (MeOH), respectively, in hexanes at 25 °C.
- Duffy, Ian R.,Leigh, William J.
-
supporting information
p. 5029 - 5044
(2015/11/09)
-
- Palladium-catalyzed dehydrostannylation of n-alkyltin trichlorides
-
[Pd(PPh3)4] catalyzes the dehydrostannylation of n-alkyltin trichlorides into HSnCl3(THF)n and isomers of the corresponding alkene. The reaction mechanism involves oxidative addition of the Sn-C bond followed by β-H elimination from the resulting n-alkylpalladium trichlorostannyl species. Rate-determining reductive elimination of HSnCl3 from cis-[PdH(SnCl3)(PPh 3)2] completes the catalytic cycle. Organotin trichlorides without β-H atoms either do not react or undergo thermal disproportionation. These results are relevant to understand some of the problems associated with the use of monoalkyltin compounds as coupling partner in Stille-type cross-coupling reactions as well as with the catalytic hydrostannylation of 1-alkenes to monoalkyltin trichlorides. The Royal Society of Chemistry 2011.
- Cabon, Yves,Gebbink, Robertus J. M. Klein,Deelman, Berth-Jan
-
p. 8651 - 8655
(2011/10/10)
-
- Tri- and diorganostannates containing 2-(N,N-dimethylaminomethyl)phenyl ligand
-
The C,N-chelated tri and diorganotin(IV) chlorides react with both protic mineral acids and carboxylic acids. The nitrogen atom of the LCN ligand (where LCN is 2-(dimethylaminomethyl)phenyl) is thus quarternized - protonated and new Sn-X bond (X = Cl, Br, I or the remainder of the starting acid used) is simultaneously formed. The set of zwitterionic tri and diorganostannates containing protonated 2-(dimethylaminomethyl)phenyl-moiety was prepared and structurally characterized by multinuclear NMR spectroscopy and XRD techniques. In all these cases, the intramolecular N-H?X bond is present in the molecule. Despite the central tin atom remains five-coordinated (except for the [HLCNH]+[(n-Bu)2SnCl(NO 3)2]-) and reveals a distorted trigonal bipyramidal geometry, the 119Sn NMR chemical shift values of these zwitterionic stannates are somewhat shifted to the higher field than corresponding starting C,N-chelated tri and diorganotin(IV) halides. Reactions of C,N-chelated organotin(IV) halides with various Lewis acids are also discussed.
- ?vec, Petr,?erno?ková, Eva,Padělková, Zdeňka,R??i?ka, Ale,Hole?ek, Jaroslav
-
p. 2475 - 2485
(2010/11/16)
-
- Reverse Kocheshkov reaction - Redistribution reactions between RSn(OCH2CH2NMe2)2Cl (R = Alk, Ar) and PhSnCl3: Experimental and DFT study
-
A series of organotin compounds bearing two intramolecular N → Sn coordination bonds RSn(OCH2CH2NMe2)2Cl (R = Me (4), n-Bu (5), Mes (6)) were synthesized in good yields. These compounds as well as 2 (R = Ph) react with PhSnCl3 to give redistribution products RPhSnCl2 and (Me2NCH2CH2O)2SnCl 2 (3). The direction of redistribution reactions is reverse to Kocheshkov reaction. DFT calculations have shown that the driving force of the reactions is formation of intramolecular N → Sn coordination bonds in (RO)2SnCl2 (3), the Lewis acid stronger than RSn(OR)2Cl (2, 4-6). The mechanism of the redistribution reaction between 2 and PhSnCl3 consists of two steps: (1) initial exchange of OCH2CH2NMe2 and Cl to give PhSn(OCH2CH2NMe2)Cl2 (7) followed by (2). Ph and OCH2CH2NMe2 exchange.
- Portnyagin, Ivan A.,Lunin, Valery V.,Nechaev, Mikhail S.
-
p. 3847 - 3850
(2009/04/06)
-
- A novel route for the preparation of dimeric tetraorganodistannoxanes
-
The reaction of polymeric diorganotin oxides, (R2SnO)n (R = Me, Et, n-Bu, n-Oct, c-Hex, i -Pr, Ph), with saturated aqueous NH4X (X = F, Cl, Br, I, OAc) in refluxing 1,4-dioxane afforded in high yields dimeric tetraorganodistannoxanes, [R2(X)SnOSn(X)R2]2, and in a few cases diorganotin dihalides or diacetates, R2SnX2. The reported method appears suitable for the synthesis of fluorinated tetraorganodistannoxanes. Identification of [R2(OH)SnOSn(X)R2]2 (R=n-Bu; X = Cl, Br) and [R2(OH)SnOSn(X)R2] [R2(X)SnOSn(X)R2] suggest a serial substitution mechanism starting from [R2(OH)SnOSn(OH)R2]2. X-ray crystal structure determinations are reported for [Me2(AcO)SnOSn(OAc)Me2]2 (29a), [i-Pr2(Br)SnOSn(Br)i-Pr2]2 (20a), [c-Hex2 (F)SnOSn(F)c-Hex2]2 (5a) and [c-Hex2(F)SnOSn(Cl)c-Hex2]2 (36), respectively. These show the presence of a central (R2Sn)2O2 core that is connected, via the oxygen atoms, to R2Sn entities. Acetate (29a) or halides (5a, 20a, 36) complete the coordination about the tin centres.
- Beckmann, Jens,Dakternieks, Dainis,Kuan, Fong Sheen,Tiekink, Edward R.T
-
-
- Synthesis and reactivity of stannyloligosilanes, I. Stannyloligosilane chains containing SiMe2 moieties
-
Stannyloligosilanes 1 and 2 with terminal organotin groups are available by reacting alkali metal tri-or diorganostannides with α,ω-dichloro-or difluorosilanes, or by treatment of organochlorostannanes with α,ω-difluorosilanes in the presence of magnesium. Attempts to functionalize the triorganotin derivatives 2 by halogenation reagents did not result in the halogen compounds 5; instead cleavage of silicon-tin bonds is observed. In contrast, reactions of the hydridotin derivatives 1 with CHX3 (X = Cl, Br) lead to the quantitative formation of the bis(chloro-or bromostannyl)oligosilanes 5. All compounds were characterized by NMR, IR, MS and elemental analysis. In addition, the triorganotin compound 2i and the hydridotin species 1b have been characterized by X-ray crystallography.
- Uhlig, Frank,Kayser, Christian,Klassen, Ralph,Hermann, Uwe,Brecker, Lothar,Schürmann, Markus,Ruhland-Senge, Karin,Englich, Ulrich
-
p. 278 - 287
(2007/10/03)
-
- Diorganotin(IV) dichloride complexes of some N-arylfurfuralnitrones
-
Some new diorganotin(IV) dichloride complexes of the general formula R2SnCl2.L, where R = Me, Bu, Ph; L = OCH=CHCH=C-CH=N(O)C6H4X (X = H. p -CH3, CH3O, CH3CO, F, Cl or Br) have been prepared and characterized by elemental analyses, and IR, 1H and 13C NMR spectroscopy. The spectral data show that the nitrone ligands coordinate with tin through the most active oxygen atom of the N-oxide to give penta-coordinate tin complexes. An explanation for such observations is given.
- Al-Allaf, Talal A. K.,Abdul-Rahman, Amer
-
p. 985 - 996
(2008/10/09)
-
- Use of a domestic microwave oven in organometallic chemistry
-
Examples are presented to illustrate the great reduction in reaction time which is possible when reactions such as metallation of aromatic rings, ligand redistribution reactions, ligand synthesis, and reactions of metallo-organic species such as Al(OPri)3 with diols are carried out in PTFE containers in a conventional domestic microwave oven.Yields are generally of the same order as those obtained via conventional methods.The results suggest a significant potential value of microwave heating in organometallic chemistry.
- Ali, Mushtaq,Bond, Stephen P.,Mbogo, Shaaban A.,McWhinnie, William R.,Watts, Philip M.
-
-
- Reactions of Thionyl Chloride with Tetraorganotin(IV) Compounds
-
The reactions of thionyl chloride with tetraorganotin(IV) derivatives (R4Sn where R = CH3, C2H5, n-C3H7, n-C4H9, C6H5CH2, C6H4CH3) bring about cleavage of tin-carbon bonds to give dialkyl/aryltin(IV) and alkyl/aryl sulphinyl chlorides.The ease of cleavage observed on the basis of the reactivities of R4Sn follows the order: n-C4H9 > n-C3H7 > C2H5 > CH3 > C6H5CH2 >> C6H4CH3.This order is not the same as commonly known in literature.
- Narula, Suraj P.,Sharma, R. K.,Lata, Sneh,Walia, Rita
-
p. 246 - 247
(2007/10/02)
-
- Synthesis of tetraphenylstannacyclopentadienes (stannoles). 2. Derivatives and adducts of 1,1-dihalo-2,3,4,5-tetraphenylstannoles
-
1,1-Dibromo- and 1,1-diiodo-2,3,4,5-tetraphenyl-1-stannacyclopentadiene, dihalotetraphenylstannoles [XYSnC4(C6H5)4], can be derivatized to form a series of disubstituted products in which X = Y = N3, iso-NCO, iso-SCN, OC(O)CH3, SC(S)N(C2H5)2, N(CH3)2, and P(C6H5)2. Fluorination by KF in acetone results in the X = F, Y = Br, or Y = I product only, and lithioamination by LiN[Si(CH3)3]2 yields the X = N[Si(CH3)3]2, Y = Br product only. Attempted synthesis of the dihalostannoles by halogenation of the intermediate tin(II) stannole from 1,4-dilithio-1,2,3,4-tetraphenyl-1,3-butadiene and tin(II) chloride yields only the ring-opened products (4-bromo-1,2,3,4-tetraphenylbutadienyl)tin tribromide or (4-iodo-1,2,3,4-tetraphenylbutadienyl)tin triiodide. Even gentle chlorination of hexaphenylstannole by elemental chlorine cleaves the ring tin-carbon bonds to form cis,cis-1,4-dichloro-1,2,3,4-tetraphenyl-1,3-butadiene and diphenyltin(IV) dichloride, while the action of a glacial acetic acid-acetic anhydride mixture yields tetraphenylfuran and diphenyltin(IV) diacetate. The dihalostannoles form neutral adducts with pyridine, 2,2′-bipyridyl, and 1,10-phenanthroline and the double salt [XSnC4(C6H5)4·terpy] +[X2YSnC4(C6H5) 4]- from 2,2′,2″-terpyridine where X = Y = Br, I = F, and Y = I. The structures of the substituted stannoles and the adducts of the dihalostannoles are discussed on the basis of tin-119m Mo?ssbauer and infrared spectroscopic evidence.
- Gustavson,Principe,Min Rhee,Zuckerman
-
p. 3460 - 3468
(2008/10/08)
-
- Reactions of Tin-Naphthyl Bond with Halogens and Pseudohalogens
-
Reactivity of Sn-phenyl or Sn-naphthyl bond in tetraorganotins, PhnSnNp4-n (Ph = phenyl, Np = α-naphthyl; n = 2,3) towards halogens (Br2 and I2), interhalogens (IBr and ICl), interpseudohalogens (BrCN and ICN) and pseudohalogen (SCN)2 has been studied.It is found that the Sn-Np bond is preferentially cleaved yielding in most cases phenyltin derivatives along with the corresponding α-naphthyl halides.
- Bhattacharya, S. N.,Husain, Ishrat
-
p. 1119 - 1121
(2007/10/02)
-