Chain polymers, five-coordination

One dithiophosphate bidentate One dithiophosphate bridging Helical chain polymer Mercury five-coordinate... 

Leznoff and co-workers reported the structural characterization and the polymorphic nature of a gold(I)-copper(II) coordination polymer, [Cu Au(CN)2 2(dmso)2] 00 [125]. In a green polymorphic form it possessed a 1-D chain structure with five-coordinate copper(II) centers, while a 2-D corrugated sheet structure with six-coordinate copper(II) centers was characterized in the blue polymorph, both of which are linked together to form a 3-D structure via aurophilic interactions. These two polymorphs exhibited virtually identical vapochromic behavior towards water, MeCN, dioxane, dmf, pyridine and ammonia, with the formation of [Cu Au(CN)2 2(solvent)x]oc,. 

Some triorganotin carboxylate structures, in particular those containing two RsSn moieties, deserve additional comment because their structures are more varied. For example, rare types of organotin carboxylates include derivatives of carborane-carboxylic acids [ (l,7-C2BioHn-l-COO)Bu2Sn 20]2 (structure of type A) [451]. The bis(triphenyltin) derivative of phenylmaleic acid, 145, contains only four-coordinate tetrahedral tin (Sn O 2.077 and 2.090 A) and is not associated, but in the bis(triphenyltin) citraconate, 146, one tin atom participates in the supramolecular association, 147, and polymer-chain formation and becomes five-coordinate (trigonal pyramidal Sn-O 2.193 A, Sn O 2.397 A) whereas the second remains four-coordinate (Sn-O 2.089 A), as a part of a dangling side chain [441]. 

Finally it is noteworthy that extended-chain metal-alkyUdyne polymers [W /r-C(4)C6H2N-3,5-Me2 (OBn )3l and [W /i-C(3)CeH4N (OBu )3] have been structurally characterized. In the 4-alkynyl-3,5-dimelhylpyridyl complex the tungstens are in the square pyramidal five-coordination but in the 3-alkynylpyridyl complex the tungstens adopt the TBP configuration. ... 

In the a-modifications of silver(I) diethyldithiocarbamate irregular hexamers are linked in chains by weak bonds only (Ag—-S = 299pm). Two of the six silver atoms have four-fold coordination, the others three-fold. Two ligands coordinate to only two metal atoms, the others to four. Five short metal-metal distances occur in each of the hexamers.323 In the /3-modification, which is a true high polymer, all the silver atoms have four-fold coordination and all the ligands are linked to three metal atoms, (39). There are only two short metal-metal distances per six silver atoms. Crystals of the /3-form were obtained from CS2 solutions cooled to -40 °C. Ag—S bond lengths were in the range 251-274 pm.324... 

Complex 3 is a one-dimensional chain coordination polymer (Fig. 3). The SBU in 3 is the predominant structural form in five types of the dimeric... 

---