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. The equivalent Sn-S values for 4, 5, and 6 are 90%, 73%, and 71%, respectively. The geometry of compound 3 is complicated by intermolecular dimerization via bridging chlorines creating a distorted octahedral geometry at tin. The related dichloro sulfur compound 6 also exhibits an intermolecular association in the form of Sn-Cl-H hydrogen bonding leading to a polymeric structure in the solid state. CPMAS 119Sn NMR spectroscopy suggests that the intramolecular Sn-E interactions persist in solution and also facilitated the discovery of a new crystalline form of 4, 4', that contains a Sn-S distance which is 95% the sum of the van der Waals radii.

The series of compounds (o-CH 3 SC 6 H 4 )CH 2 EPh 3 (E = Si (1), Ge (2), Sn (3), and Pb (4)) have been synthesized and characterized by NMR spectroscopy and by single crystal X-ray diffraction. Compounds 1 and 2 are isostructural with a triclinic crystal system and P-1 space group; however, morphotropic steps occur between Ge and Sn, and Sn and Pb. While the E-S distances in 1 and 2 are 3.985 and 3.974 Å, respectively,~100% of the sum of the respective van der Waals (vdW) radii, there is a notable distortion from tetrahedral geometry about E. Compound 3 is also triclinic with P-1 symmetry, but has two molecules in the unit cell that demonstrate a distorted tetrahedral geometry and intramolecular Sn-S distances of 3.699 and 3.829 Å, 88% and 91% of the sum of the vdW radii. Compound 4 has a Pb-S distance of 3.953 Å (91% of Σ vdW radii). The structure of the Grignard coupling product [o-(SCH 3 )C 6 H 4 CH 2 ] 2 is also reported.Résumé : On a réalisé la synthèse d'une série de composés de formule (o-CH 3 SC 6 H 4 )CH 2 EPh 3 dans lesquels E = Si (1), Ge (2), Sn (3) et Pb (4) et on les a caractérisés par spectroscopie RMN et par diffraction des rayons X par un cristal unique. Les composés 1 et 2 sont isostructuraux avec un système cristallin triclinique et un groupe d'espace P-1; toutefois, on notre des différences morphotropes entre le Ge et le Sn ainsi qu'entre le Sn et le Pb. Alors que les distances E-S dans les composés 1 et 2 sont respectivement de 3,985 et 3,974 Å, environ 100 % de la somme des rayons respectifs de van der Waals, on note une distorsion notable par rapport à la géométrie tétraédrique autour de E. Le composé 3 est aussi triclinique avec une symétrie P-1, mais la maille cristalline comporte deux molécules ce qui dé-montre la présence d'une géométrie tétraédrique déformée alors que les distances intramoléculaires Sn-S de 3,699 et 3,829 Å correspondent respectivement à 88 % et 91 % de la somme des rayons de van der Waals. Dans le composé 4, la distance Pb-S est de 3,593 Å (91 % de la somme des rayons de van der Waals). On a aussi déterminé la structure du produit de couplage de Grignard [o-(SCH 3 )C 6 H 4 CH 2 ] 2 .

In this physical chemistry experiment the surface tension of several solvents is measured. The surface tension is determined by measuring the height of the capillary rise in a capillary tube. The capillary tubing used is inexpensive, but its diameter is not known. The first part of the experiment involves measuring the capillary rise for several different solvents. The second part involves determining the radius of the tubing. A laser of known wavelength is passed through a short piece of the capillary tubing, creating a diffraction pattern. Assuming constant diameter, the radius of the tubing may then be calculated through measurements taken on the diffraction pattern. Students have used this method to determine the surface tension of several solvents with a relative error of less than 7 percent.

A new transition metalate system, [(η 5 -Me 3 SiC 5 H 4 )Fe(CO)(PPh 3 )] -M þ (SiFpPM; M = Li, Na), was synthesized via treatment of (η 5 -C 5 H 5 )Fe(CO)(PPh 3 )SiMe 3 with sodium and lithium diisopropylamides (MN(iPr 2 ); NADA and LDA, respectively). The utility of NADA was far superior to that of LDA, with shorter reaction times, lower reagent concentrations, and higher yields. Infrared spectroscopic analysis of the new ferrates indicated that their stability and utility were dependent upon the tight ion pairs Fe-CO-M; in the presence of coordinating solvents and ionophores the separated ion pairs formed led to the expulsion of the PPh 3 and CO scavenging led to formation of the dicarbonylferrate [(η 5 -Me 3 SiC 5 H 4 )Fe(CO) 2 ] -M þ . Hexane was the solvent of choice for formation and use of the ferrates. Reactions of the new ferrates with MeI led to [SiFpP]CH 3 , whereas reactions with ClCH 2 SiMe 2 R (R = H, SiMe 3 ) did not lead to the expected Fe-C bonded complexes [SiFpP]CH 2 SiMe 2 R but to high yields of the rearranged complexes [SiFpP]SiMe 2 CH 2 R. The presence of the thermally labile phosphine group readily produces a coordinatively unsaturated 16e species that permits Fe-CH 2 -SiMe 2 R to FeSiMe 2 CH 2 R rearrangements (previously observed photochemically with the simple Fp derivatives) to occur thermally.

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