Metal dithienes

Coordination compounds with delocalised ground states. The transition metal derivatives of dithioketones and ethylene(l,2)dithiolates (metal dithienes). G. N. Schrauzer, Acc. Chem. Res., 1969,2,72-80 (36). 

Recent Advances in the Chemistry of Transition Metal Complexes of Unsaturated Bidentate Sulfur Donor Ligands (Metal Dithienes)... 

Complexes of most transition metals have become accessible by improved methods of synthesis. The most general method utilizes acyloins as starting materials which react first with P4S10 to afford thiophosphates of substituted cis-l,2-ethylenedithiols. The latter react with metal salts in aqueous solution to give metal dithienes (4),... 

This apparent analogy is justified by a topological comparison of the TT-electron system of the metal dithiene with that of the quinone. The vertical carbon and oxygen 2p orbitals of p-benzoquinone (symmetry... 

Alkylation. The topological analogies outlined in the previous section are substantiated further by considering the chemistry of metal dithienes. We first discuss the alkylation of anionic species. This reaction is equivalent to the alkylation of the hydroquinone dianion and aflFords members of a class of new coordination compounds (14). With simple alkyl halides the d metal dithiene dianions aflFord the 1,4-S-dialkylderiva-tives (16). With a,a>-dibromoalkanes at high dilution new chelates of type 17 were obtained for x = 5-12 (3). With smaller values of x or... 

Equation 7 is related to a Diels-AIder type reaction and led us to examine the reaction of metal dithienes with reactive olefins. With norbomadiene (bicyclo[2.2.1]hepta-2,5-diene) in homogeneous solution (CH2CI2 is a convenient solvent), the Diels-Alder adduct 26 is formed in high yield with the oligomeric nickel(II)-stilbenedithiolate (25) (i6, 17) ... 

The resistivities of metal dithienes compare with those of Ovalene (p = 2,3 X 10 ohm-cm), violanthrone (2.3 X 10 ohm-cm), or cy-ananthrone (1.2 X 10 ohm-cm) (19). Metal phthalocyanines with reported resistivities of between 10 and 10 ohm-cm, are worse semiconductors than the dithienes. The conductivity of some rhenium dithienes approaches that of intrinsic silicon even better conductors may result by synthesizing polymeric species. 

Complexes of 1,2-dithiotropolone were predicted to possess properties different from metal dithienes, the ligand being a typical odd system (I). Forbes and Holm (27) reported recently the synthesis of the ligand and a number of complexes which confirm this proposal. 

I express my thanks and appreciation to my co-workers and colleagues who have participated in the work on metal dithienes. At Munich, V. P. Mayweg, W. Heinrich, and H. W. Finck. At Shell Development Co., E. J. Rosa, A. E. Smith, and D. C. Olson. At La Jolla, H. N. Rabino-witz, R. P. Murillo, and R. K. Y. Ho. Particular thanks are also extended to I. C. Paul (Urbana, 111.) for confirming the structure of complex 36 by single crystal x-ray diffraction. 

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