TMEDA bridges

In the presence of TMEDA, a 3-D brickwall coordination polymer of TMEDA-supported dimeric, less bulky 2,3-dialkyl-l,4-dilithio-1,3-butadiene If was formed, which has been confirmed by X-ray analysis (Type IV, Scheme 3) [32]. The expected TMEDA-chelated monomeric structure IF as a deaggregation product was not formed. As shown in Fig. 2 and Scheme 3, in monolayer of 3-D brickwall polymeric structure of If, six Li4 cores and six TMEDA bridges composed a chairlike macrocyclic unit. The macrocyclic unit extends to form 2-D brickwall mono-layer via N-Li coordination. The brickwall monolayers are linked by TMEDA molecules to form the 3-D network, also forming chair-Uke Li4-TMEDA... 

Analogous to the dithiophosphate complexes, cis octahedral complexes are formed with bident-ate ligands like phenanthroline, 2,2 -bipyridine, or tmeda and trans octahedral complexes are formed with monodentate ligands like pyridine and its derivatives. Some examples are mentioned with linear bidentate ligands like 4,4 -bipyridine, which build up ID chains by bridging the [NiL2] molecules.926-933... 

Zinc dithiocarbamates have been used for many years as antioxidants/antiabrasives in motor oils and as vulcanization accelerators in rubber. The crystal structure of bis[A, A-di- -propyldithio-carbamato]zinc shows identical coordination of the two zinc atoms by five sulfur donors in a trigonal-bipyramidal environment with a zinc-zinc distance of 3.786 A.5 5 The electrochemistry of a range of dialkylthiocarbamate zinc complexes was studied at platinum and mercury electrodes. An exchange reaction was observed with mercury of the electrode.556 Different structural types have been identified by variation of the nitrogen donor in the pyridine and N,N,N, N -tetra-methylenediamine adducts of bis[7V,7V-di- .vo-propyldithiocarbamato]zinc. The pyridine shows a 1 1 complex and the TMEDA gives an unusual bridging coordination mode.557 The anionic complexes of zinc tris( V, V-dialkyldithiocarbamates) can be synthesized and have been spectroscopically characterized.558... 

Li(TMEDA)+ cations reveals one lithium atom closely bound to the open face and the other bridging the two boron-attached hydrogen atoms.127... 

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