Pentacoordinated molecules. 49. A tin four- to five-coordinate reaction path. Molecular structures of the cyclic stannanes, (tert-Bu)2Sn(OCH2CH2)2NMe and Me2Sn(SCH2CH2)2NMe

Spirocyclic bisphenoxides of Ge, Zr, and Sn as catalysts for ring‐expansion polymerizations of l‐ and meso‐lactide

“…Such DA interactions are not mere speculation; experimental evidence was reported for cyclic dibutyl tin ethers and amines (stannatranes) . Therefore, it is not unlikely that an analogous DA activation also exists in SnNaph 2 ‐containing cyclic lactides and is responsible for an exclusive formation of odd cycles.…”

Tin Organometallic Compounds: Classification and Analysis of Crystallographic and Structural Data: Part 1. Monomeric Derivatives

“…The most common form of distortion isomerism [22] is where two or more crystallographically independent molecules are found within the same crystal. Tin follows this trend with two such molecules [2,11,19,31,50,67,75,80,82,84,88,93,95,100,110,117,123,124,140, 142,168,175,176,187,189,191,197,212,213,218,21,225,245,253,258,270,280,298,303,304, 317,318,320,327,330,346,382,410,428,430,435,441,463,471,478,480,481,501,504,511,535,544,5 46,554,582,626,681,682,686,738,739]; three such molecules [31,168,459]; and four such molecules [160,166,204,316,398], While the mean Sn(ll)-C bond distances increases with an increase in coordination number, this is not the case for Sn(IV)-C bond distances. For example, for tin(ll) the values are 221 pm (two coordinate) and 228.5 pm (for three coordinate (Tables 1 and 2).…”

“…In consideration of the denticity of the ligand, the internal ring L-Sn-L angles Two derivatives exist in two isomeric forms, differing mostly by degree of distortion, SnPh 3 (N0 3 )(pyN0) which is triclinic [330] and monclinic [331}, and Sn{N(CH 2 CH 2 CH 2 ) 3 }CI as monoclinic and hexagonal [428]. Another example, SniBu'^OCHaCI-^NMe} [459] has three crystallographically independent molecules in the same crystal. Another pair of examples, SnMe 3 (2-pycar)(H 2 0) [316] and SnPh 3 {i-2-0 2 Cquto}CI [398] has four independent distortion isomers within the same crystal.…”

Optically active pentacyclic binuclear diorganotin compounds

“…The syntheses were performed by reaction of compound 1 and the corresponding organometallic compounds R 2 SnCl 2 in ethanol and in presence of triethylamine, Scheme 2. The two penta-coordinated tin atoms are stereogenic centers and therefore an isomeric mixture should be expected; however, the reactions gave only one isomer in each case, due to the rigid and planar array of the ligand, which implies that reactions have been stereoselective [9][10][11].…”