Control of Λ- and Δ-Isomerization of the Atrane Cages in Group XIV Metallatranes by Chiral Axial Substituents.

The syntheses of the novel stannatranes N(CHCMeO)Sn-(1 S)-(-)-OC(O)C(OMe)(CF)(CH), 1( S, Δ), and N(CHCMeO)Sn-(1 R)-(+)-OC(O)C(OMe)(CF)(CH), 2( R, Λ), and germatranes N(CHCMeO)Ge-(1 S)-(-)-OC(O)C(OMe)(CF)(CH), 3( S, Δ), and N(CHCMeO)Ge-(1 R)-(+)-OC(O)C(OMe)(CF)(CH), 4( R, Λ) (with 1, S, Δ-configured/2, R, Λ-configured and 3, S, Δ-configured/4, R, Λ-configured being pairs of enantiomers) are reported. The compounds were characterized by NMR and IR spectroscopy, electrospray ionization mass spectrometry, and single crystal X-ray diffraction analysis. The epimerization via Λ ⇌ Δ ring flip of the enantiomeric stannatrane pair 1( S, Δ)/2( R, Λ) was investigated by NMR experiments at variable temperatures and density functional theory (DFT) calculations.

Cis versus Trans: The Coordination Environment about the Tin(IV) Atom in Spirocyclic Amino Alcohol Derivatives.

The syntheses of amino alcohols MeN(CH CH CMe OH) (1), MeN(CMe CH OH)(CH CMe OH) (2), MeN(CH CH CH OH)(CH CMe OH) (3), MeN(CH CH CMe OH)(CH CMe OH) (4), MeN(CH CH CMe OH)(CH CH OH) (5), and MeN(CH CH OH) (CH CH CH OH) (6) as well as spirocyclic tin(IV) alkoxides spiro-[nBuN(CH CMe O) ] Sn (7), spiro-[MeN(CH CH CMe O) ] Sn (8), spiro-[para-FC H N (CH CMe O) ] Sn (9), spiro-[MeN(CMe CH O)(CH CMe O)] Sn (10), spiro-[MeN(CH CH CH O)(CH CMe O)] Sn (11), spiro-[MeN(CH CH CMe O)(CH CMe O)] Sn (12), spiro-[MeN(CH CH CMe O)(CH CH O)] Sn (13) and spiro-[MeN(CH CH O)(CH CH CH O)] Sn (14) are reported. The compounds were characterized by H, C (1-14) and Sn (7-14) NMR and IR spectroscopy, EIMS and single-crystal XRD (2, 7-10 and 13, 14). Graph-set analyses were performed for compounds [(MeNH(CMe CH OH)(CH CMe OH)][HC(O)O] (2 a) and 2.

F-Radiolabeling and In Vivo Analysis of SiFA-Derivatized Polymeric Core-Shell Nanoparticles.

Nanoparticles represent the most widely studied drug delivery systems targeting cancer. Polymeric nanoparticles can be easily generated through a microemulsion polymerization. Herein, the synthesis, radiolabeling, and in vivo evaluation of nanoparticles (NPs) functionalized by an organosilicon fluoride acceptor (SiFA) are reported which can be radiolabeled without further chemical modifications.

Introducing Stereogenic Centers to Group XIV Metallatranes.

The syntheses of the novel amino alcohols NH(CHCMeOH)(CMeCHOH) (1) and N(CHCMeOH)(CMeCHOH)(CHCHOH) (2) as well as the stannatranes N(CHCMeO)(CMeCHO)(CHCHO)SnX (3, X = Ot-Bu), N(CHCMeO)SnOC(O)CHO, 4, and germatranes N(CHCMeO)(CMeCHO)(CHCHO)GeX (5, X = OEt; 6, X = Br) are reported. The compounds were characterized by H, C (1-6), Sn (3, 4), and N (2, 3, 5) NMR and IR spectroscopy, electrospray ionization mass spectrometry, and single crystal X-ray diffraction analysis. Graphset analyses were performed for compounds 1 and 2.

Hydrosilylation of RN=CH Imino-Substituted Pyridines without a Catalyst.

Treatment of the neutral pyridine-based ligands L -L , bearing either one or two RN=CH imine moieties {where L and L are N,N-chelating ligands 2-(RN=CH)C H N (R=Ph (L ) or R=2,4,6-Ph C H (L )) and L is the N,N,N-chelating ligand 2,6-(RN=CH) C H N (R=2,6-iPr C H )}, with HSiCl yielded N→Si-coordinated silicon(IV) amides 2-{Cl SiN(R)CH }C H N (1, R=Ph; 2, R=2,4,6-Ph C H ) and 2-{Cl SiN(R)CH }-6-(RN=CH)C H N (3, R=2,6-iPr C H ). The organosilicon amides 1-3 are the products of spontaneous hydrosilylation of the RN=CH imine moiety induced by N→Si coordination of the proposed N,N-chelated chlorosilanes L →SiHCl (1 a), L →SiHCl (2 a), and L →SiHCl (3 a). Furthermore, the reaction of L with an excess of HSiCl provided the intramolecularly coordinated chlorosilicon diamide cyclo-{(C H N)-1,3-(CH NR) }SiCl (4) (R=2,6-iPr C H ) as the product of spontaneous reduction of both RN=CH imine moieties.

Novel Stannatrane N(CHCMeO)(CMeCHO)SnO-t-Bu and Related Oligonuclear Tin(IV) Oxoclusters. Two Isomers in One Crystal.

The syntheses of the alkanolamine N(CHCMeOH)(CMeCHOH) (1), of the stannatrane N(CHCMeO)(CMeCHO)SnO-t-Bu (2), and of the trinuclear tin oxocluster 3 consisting of the two isomers [(μ-O)(O-t-Bu){Sn(OCHCMe)(OCMeCH)N}] (3a) and [(μ-O)(μ-O-t-Bu){Sn(OCHCMe)(OCMeCH)N}] (3b) as well as the isolation of a few crystals of the hexanuclear tin oxocluster [LSnOSn(OH)LSnOH] [L = N(CHCMeO)(CMeCHO)] (4) are reported. The compounds were characterized by H, C, N, and Sn (1-3) nuclear magnetic resonance and infrared spectroscopy, electrospray ionization mass spectrometry, and single-crystal X-ray diffraction analysis (1-4). A graph set analysis was performed for compound 1.

N-Coordinated Tin(II) Trifluoromethanesulfonates and Their Reactions with Transition Metal Carbonyls.

The syntheses of the compounds [L(1)SnCl][M(CO)5(SnCl3)] (3, M = W; 4, M = Cr), [L(1)SnCl]OTf (5), [L(1)SnCl][W(CO)5(SnCl2OTf)] (6), [L(1)SnOTf][OTf] (7), and [L(2)Sn(OTf)2] (8) with L(1) = {2,6-[(CH3)C═N(C6H3-2,6-(i)Pr2)2]C5H3N} (DIMPY) and L(2) = {2-[(CH3)C═N(C6H3-2,6-(i)Pr2)]-6-(CH3O)}C5H3N) is reported. The compounds were characterized by elemental analyses, (1)H, (13)C, (19)F, and (119)Sn NMR spectroscopy, electrospray ionization mass spectrometry, and single-crystal X-ray diffraction analyses (3·1.5C7H8, 5·CH2Cl2, 7·C7H8, 8).

Investigations on diffusion limitations of biocatalyzed reactions in amphiphilic polymer conetworks in organic solvents.

The use of enzymes as biocatalysts in organic media is an important issue in modern white biotechnology. However, their low activity and stability in those media often limits their full-scale application. Amphiphilic polymer conetworks (APCNs) have been shown to greatly activate entrapped enzymes in organic solvents.