Hypercoordination by Multiple Dangling Benzylmethoxy Ligands in Highly Crowded Triaryltin Bromide [(2-MeOCH C H )] SnBr and Diaryltin Mixed Halides [(2-MeOCH C H )] SnBrCl, and a related Distannane and Distannoxane.

The reaction between the Grignard reagent formed from Mg and 2-bromobenzylmethyl ether and SnCl produced four products: [2-(MeOCH )C H ] SnBr (1), [2-(MeOCH )C H ] SnX (2, X =Br (a) and BrCl (b)), [{2-(MeOCH )C H } Sn] (3), and [{2-(MeOCH )C H } SnBr] O (4). In the case of 1, two of the three dangling arm O atoms coordinate to the central tin atom with O-Sn internuclear distances of 2.53 (O1) and 2.

Resonance and electrostatics making the difference in boron- and aluminum-halide structures and exchange reactivity.

The mechanism of the gas-phase halogen-exchange reaction between boron- and aluminum-halides (i.e., BX + BX and AlX + AlX, X = F, Cl, or Br) was discovered using density functional theory.

Hypercoordinated eka-tin materials with dangling aryl-methoxy and -methylthio ligands exhibiting intramolecular secondary bonding and aryl bond stabilization in reactions with organotin chlorides.

The syntheses of [2-(CHECH)CH]PbPhCl, ( = 0, E = O (4), E = S (5); = 1, E = O (6), E = S (7); = 2, E = O (8), are described. NMR and single crystal data illustrate significant Pb⋯E interactions increasing as n progresses from 0 to 2. The Pb⋯E interactions stabilize the Pb-aryl bonding to the extent that the reactions of 4 and 5 with MeSnCl result in interchange of a Ph group and Cl to produce 6 and 7, respectively, together with MePhSnCl.

Aminomethyl Transfer (Mannich) Reactions Between an O-Triethylsilylated Hemiaminal and Anilines, R C H NH Leading to New Diamines, Triamines, Imines, or 1,3,5-Triazines Dependent upon Substituent R.

The reactions of the Mannich reagent Et SiOCH NMe (1) with a variety of anilines (mono-substituted RC H NH , R=H, 4-CN, 4-NO , 4-Ph, 4-Me, 4-MeO, 4-Me N; di-substituted R C H NH , R =3,5-(CH ) , 3,5-(CF ) ; tri-substituted R C H NH , R =3,5-Me -4-Br and a "super bulky" aniline (Ar*NH ) [Ar*=2,6-bis(diphenylmethyl)-4-tert-butylphenyl]) led to the formation of a range of products dependent upon the substituent. With electron-withdrawing substituents, previously unknown diamines, RC H NH(CH NMe ) [R=CN (2 a), NO (2 b)] and R C H NH(CH NMe ) [R =3,5-(CF ) (2 c)] were formed. Further reaction of 2 a, b, c with 1 yielded the corresponding triamines RC H N(CH NMe ) (R=CN (3 a), NO (3 b) and R C H N(CH NMe ) , R =3,5-(CF ) (3 c).

A utility for organoleads: selective alkyl and aryl group transfer to tin.

MePb and PhPb readily transfer methyl or phenyl groups to an equivalent molar ratio of tin(iv) chlorides in the order SnCl > MeSnCl > MeSnCl > MeSnCl, often in a selective manner. MePbCl and PhPbCl specifically transfer a single methyl/phenyl group under the same reaction conditions to produce recovered yields in >75%. Specific transfer of 2 methyl groups from PbMe can be achieved at elevated temperatures and/or a 2 : 1 molar ratio Pb : Sn.

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)4 ] Complexes.

Compound Et3 SiOCH2 NMe2 transfers Me2 NCH2 to R2 NH (R2 =Et2 , PhMe, [Cr(η(6) -C6 H5 )(CO)3 ]Me, PhH) to form previously unknown diaminomethanes, Me2 NCH2 NR2 and, in the case of R2 =PhH, the triamine Me2 NCH2 N(Ph)CH2 NMe2 . The diaminomethanes exhibit an unreported disproportionation to a mixture of (R2 N)2 CH2 , (Me2 N)2 CH2 , and Me2 NCH2 NR2 , which can be trapped as their [Mo(CO)4 (diamine)] complexes. Whereas PhMeNCH2 NMe2 is a labile material, the metal-substituted ([(η(6) -C6 H5 )Cr(CO)3 ]MeNCH2 NMe2 is a stable material.

Platinum-Catalyzed Reduction of DMF by 1,1,3,3-Tetramethyldisiloxane, HMeSiOSiMeH: New Intermediates HSiMeOSiMeOCHNMe and HSiMe(OSiMe)OCHNMe and Their Further Chemical Reactivity.

The use of Karstedt's catalyst to study the reduction of MeNCHO (DMF) by the popular "dual SiH"-containing tetramethyldisiloxane, HMeSiOSiMeH (), has revealed that the first step in the process involves an initial single hydrosilylation to form HSiMeOSiMeOCHNMe (). This intermediate is readily isolated and purified via distillation. In the continued presence of the catalyst, transforms to the transient tetrasiloxane HMeSiOSiMeOSiMeOSiMeOCHNMe (), along with the formation of MeN.

8-Alkoxy- and 8-aryloxy-BODIPYs: straightforward fluorescent tagging of alcohols and phenols.

We demonstrate herein that both alcohols and phenols can be tagged with a BODIPY (borondipyrromethene) moiety to yield highly fluorescent products. Thus, 8-(methylthio)-BODIPY (1) undergoes an S(N)Ar-type reaction with a host of alcohols and phenols in the presence of a base and a Cu(I) additive. The BODIPY dyes bearing alkoxy or nonfunctionalized phenoxy moieties are characterized by a highly efficient fluorescence emission, regardless of the media, in the blue-green part of the visible region.

8-Amino-BODIPYs: structural variation, solvent-dependent emission, and VT NMR spectroscopic properties of 8-R2N-BODIPY.

New 8-NR2-BODIPYs, R2 = H(i)Pr (3a), H(i)Bu (3b), and Et2 (4), are reported. Restricted rotation about the C8-N bond in such molecules has been observed for the first time (3a and 3b) and evaluated using VT NMR. The fluorophores 3a and 3b are blue emitters, and the efficiency of the emission is closely related to the polarity of the solvent, e.

Metal-catalyzed reduction of HCONR'2, R' = Me (DMF), Et (DEF), by silanes to produce R'2NMe and disiloxanes: a mechanism unraveled.

We demonstrate that using Mo(CO)(6), Mo(CO)(5)NMe(3), and (η(5)-C(5)H(5))Mn(CO)(3) as catalysts for the silane, R(3)SiH, reduction of N,N-dimethylformamide (DMF), and N,N-diethylformamide (DEF), we can observe, intercept, and isolate, the important siloxymethylamine intermediates, R(3)SiOCH(2)NR'(2), R' = Me, Et, for the first time. In the presence of excess DMF such intermediates thermally react with a variety of silanes to form the corresponding disiloxanes in the absence of a metal catalyst. We also show that the germanium hydrides, Et(3)GeH and Bu(3)GeH, also reduce DMF to form trimethylamine and the corresponding digermoxane but observe no intermediates R(3)GeOCH(2)NMe(2).

Cytotoxic effects of two organotin compounds and their mode of inflicting cell death on four mammalian cancer cells.

In this report, we have tested the cytotoxicity of two organotin (OT) compounds by flow cytometry on a panel of immortalized cancer cell lines of human and murine origin. Although the OT compounds exhibited varying levels of cytotoxicity, diphenylmethyltin chloride was more toxic than 1,4-bis (diphenylchlorostannyl)p-xylene on all cell lines tested. The OT compounds were found to be highly cytotoxic to lymphoma cell lines with lower toxicity toward the HeLa cervical cancer cell line.

Arenechromiumtricarbonyl complexes of silyl(germyl)(stannyl)- and silyl(germyl)(plumbyl)methanes including unexpected formation of arenechromiumtricarbonyldimethylsilanol, (eta-C(6)H(5))Cr(CO)(3)SiMe(2)OH.

Treatment of PhMe(2)SiCH(2)GeMe(3) (1) with t-BuLi followed by addition of Me(3)ECl, E = Sn, Pb, results in the formation of phenylsilyl(germyl)stannyl- and phenylsilyl(germyl)plumbyl-methanes, PhMe(2)Si(Me(3)Ge)(EMe(3))CH, E = Sn (2), Pb (3). The thermal reaction of 1, 2 and 3 with Cr(CO)(6) yields the corresponding aryl-Cr(CO)(3) analogs, {(eta(6)-C(6)H(5))Cr(CO)(3)}Me(2)Si(Me(3)Ge)CH(2) (4) and {(eta(6)-C(6)H(5))Cr(CO)(3)}Me(2)Si(Me(3)Ge)(EMe(3))CH, E = Sn (5), Pb (6). The thermal treatment of 2 with Cr(CO)(6) in wet THF/di-n-butyl ether mixture results in the formation of the arenechromiumtricarbonyl silanol {(eta(6)-C(6)H(5))Cr(CO)(3)}Me(2)SiOH (7) which exhibits amphiphilic character, forming H-bonded chains in the solid state in a head-to-head arrangement of the areneCr(CO)(3) units.

Phosphine induced migratory CO insertion into the Fe-CH2 bond of the organometallic polymer -[(eta(5)-C5H4)Fe(CO)2CH2SiMe2]n- and characterization of model iron complexes.

Thermal and photochemical treatment of 1-sila-3-ferracyclobutane, (eta(5)C(5)H(4))Fe(CO)(2)CH(2)SiMe(2) (1) results in ring-opening polymerization (ROP). Phosphine-induced migratory CO insertion into the Fe-CH(2) bond of the preformed polymer, -[(eta(5)-C(5)H(4))Fe(CO)(2)CH(2)SiMe(2)](n)- (2) results in either linear polymers, -[(eta(5)-C(5)H(4))Fe(CO)(PR(3))C(O)CH(2)SiMe(2)](n)- [R(3) = Me(2)Ph (3), Ph(3) (4)] or diphosphine bridged polymers, -{[(eta(5)-C(5)H(4))Fe(CO)C(O)CH(2)SiMe(2)](2)(P-P)}(n)- [P-P = dppe (5), dppp (6), dppb (7), trans-dppen (8), dmpe (9); dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,2-bis(diphenylphosphino)propane, dppb = 1,2-bis(diphenylphosphino)butane, cis-dppen = cis-1,2-bis(diphenylphosphino)ethylene, dmpe = 1,2-bis(dimethylphosphino)ethane]. The analogous model complexes, {[(eta(5)-C(5)H(5))Fe(CO)C(O)CH(3)](2)P-P} [P-P = dppp (10), dppb (11), trans-dppen (12), dmpe (13)] were synthesized and characterized as models of the acylated polymers.

Methyl transfer from Fe (and Mo) to Sn: formation of (eta(5)-C(5)H(5))M(CO)(n)Sn(t)Bu(2)Me (M = Fe, n = 2; M = Mo, n = 3) complexes from photochemical irradiation of (eta(5)-C(5)H(5))M(CO)(n)Me and (t)Bu(2)SnH(2).

Formation of an Sn-CH(3) bond, concomitantly with an Sn-M (M = Fe, Mo), is readily achieved from the photochemical reactions of (t)Bu(2)SnH(2) with (eta(5)-C(5)H(5))M(CO)(n)Me (M = Fe, n = 2; M = Mo, n = 3) via the intermediacy of (eta(5)-C(5)H(5))M(CO)(n)Sn(t)Bu(2)H.

Formation of silicon-carbon bonds by photochemical irradiation of (eta-C(5)H(5))Fe(CO)(2)SiR(3) and (eta-C(5)H(5))Fe(CO)(2)Me to obtain R(3)SiMe.

Photochemical irradiation of an equimolar mixture of (eta(5)-C(5)H(5))Fe(CO)(2)SiR(3), FpSiR(3), and FpMe leads to the efficient formation of the silicon-carbon coupled product R(3)SiMe, R(3) = Me(3), Me(2)Ph, MePh(2), Ph(3), ClMe(2), Cl(2)Me, Cl(3), Me(2)Ar (Ar = C(6)H(4)X, X = F, OMe, CF(3), NMe(2). Similar chemistry occurs with related germyl and stannyl complexes at slower rates, Si > Ge> >>Sn. Substitution of an aryl hydrogen in FpSiMe(2)C(6)H(4)R' has little effect upon the rate of the reaction whereas progressive substitution of methyl groups on silicon by Cl slows the process.

Intramolecular chalcogen-tin interactions in [(o-MeEC6H4)CH2]2SnPh(2-n)Cl(n) (E = S, O, CH2; n = 0, 1, 2) and intermolecular chlorine-tin interactions in the meta- and para-methoxy isomers.

Organotin(IV) compounds of the type [(o-MeEC(6)H(4))CH(2)](2)SnPh(2-n)Cl(n) were synthesized, E = O, n = 0 (1), n = 1 (2), and n = 2 (3); E = S, n = 0 (4), n = 1 (5), and n = 2 (6); and E = CH(2), n = 0 (7), n = 1 (8), and n = 2 (9). The dichloro compounds 3 and 6 have been investigated by single-crystal X-ray diffraction and exhibit bicapped tetrahedral geometry at the tin atom as a consequence of significant intramolecular Sn..

Synthesis and cyclic voltammetric studies of diiron complexes, ER(2)[(eta-C(5)H(4))Fe(L(2))Me](2) (E = C, Si, Ge, Sn; R = H, alkyl; L(2) = diphosphine] and (eta-C(5)H(5))Fe(L(2))ER(2)Fc [Fc = (eta-C(5)H(4))Fe(eta-C(5)H(5))].

The cyclic voltammetric studies on ER(2)[(eta(5)-C(5)H(4))Fe(L(2))Me](2) (L(2) = dppe; ER(2) = CH(2) (1a), SiMe(2) (2a), GeMe(2) (3a), SnMe(2) (4a) revealed two well resolved reversible waves [(1)E(1/2) = -0.33 V, (2)E(1/2) = -0.20 V (for 1a); (1)E(1/2) = -0.

Effects of a series of triorganotins on ATP levels in human natural killer cells.

Natural killer (NK) cells are our initial immune defense against viral infections and cancer development. Thus, agents that are able to interfere with their function increase the risk of cancer and/or infection. A series of triorganotins, (trimethyltin (TMT), dimethylphenyltin (DMPT), methyldiphenyltin (MDPT), and triphenyltin (TPT)) have been shown to decrease the lytic function of human NK cells.

Intramolecular chalcogen-tin interactions in (o-MeE-C6H4)CH2SnPh3-nCln (E = S, O; n = 0, 1, 2), characterized by X-ray diffraction and 119Sn solution and solid-state NMR.

Organotin(IV) compounds of the type (o-MeE-C6H4)CH2SnPh3-nCln were synthesized, E = O, n = 0 (1), n = 1 (2), n = 2 (3) and E = S, n = 0 (4), n = 1 (5), n = 2 (6). The complexes exhibit significant trigonal bipyramidal pentacoordination at tin as a consequence of intramolecular Sn-O (1-3) and Sn-S (4-6) interactions upon substitution of the phenyl groups by chloro groups. The intramolecular Sn-O distances in 1, 2, and 3 are 83%, 75%, and 79% of the sum of the van der Waals radii.

Effect of a series of triorganotins on the immune function of human natural killer cells.

Natural killer (NK) cells are our initial immune defense against viral infections and cancer development. They are able to destroy tumor and virally infected cells. Thus, agents that are able to interfere with their function increase the risk of cancer and/or infection.

Synthesis, structural and spectroscopic characterization, catalytic properties, and thermal transformations of new cyclic di- and trisiloxanediolato tantalum complexes.

The reaction between Ta(OEt)5 and 1,1,3,3-tetramethyl-1,3-disiloxanediol, (HOSiMe2OSiMe2OH), leads to new siloxy complexes in which the dimeric nature of Ta(OEt)5 is maintained with both bridging ethoxide and disiloxanediolato bridges. With equal amounts of the reagents, two terminal OEt groups are replaced to form [Ta(OEt)2]2(mu-OEt)2(mu-OSiMe2OSiMe2O)2, 1, whereas with an excess of diol, the remaining terminal OEt groups are also replaced but with a trisiloxanediolato unit to form [Ta(OSiMe2OSiMe2OSiMe2O)]2(mu-OEt)2(mu-OSiMe2OSiMe2O)2, 2. Complexes 1 and 2 catalyze the transformation of HOSiMe2OSiMe2OH to polysiloxanes.

Investigating bidentate and tridentate carbamoylmethylphosphine oxide ligand interactions with rare-Earth elements using electrospray ionization quadrupole ion trap mass spectrometry.

Electrospray ionization (ESI) quadrupole ion trap mass spectrometry (QIT-MS) and collisionally activated dissociation (CAD) were used to evaluate the rare-earth binding properties of two hydrophobic carbamoylmethylphosphine oxide (CMPO) ligands, the normal bidentate variety, (t-BuC6H4)2P(O)CH2C(O)N(i-Bu)2 (A), a new potentially tridentate extractant, (t-BuC6H4)2P(O)CH[CH2C(O)N(i-Bu)2]C(O)N(i-Bu)2 (B), and tributyl phosphate. The mass spectral results obtained from analysis of 1% HNO3/methanol solution containing the ligands and dissolved lanthanide salts reveal that the favorable stoichiometries of the ligand/metal/nitrate complexes are 2:1:2 for the bidentate ligand A, 1:1:2 for the tridentate ligand B, and 3:1:2 for the monodentate tributyl phosphate. These observed stoichiometries correlate with the number of available binding sites on each ligand as well as with potential steric effects.

The substituent-dependent base-treatment chemistry of (eta5-C5H5)Fe(CO)2SiR2SiR2Cl: formation of 1,2-disila-3-metallacyclobutanes, their ring-opened polymers, migrations and substitutions.

We report the formation of disilametallacycles, high molecular weight polymers or simple substitution products from the reactions of 1-(cyclopentadienyliron dicarbonyl)-2-chlorodisilanes with bases, LDA or n-BuLi.