The racemic methyl complexes (η 5 -C 5 Me 5 )Re(NO)(PR 3 )(CH 3 ) (R: b, 4-C 6 H 4 CH 3 ; c, 4-C 6 H 4t-C 4 H 9 ; d, 4-C 6 H 4 C 6 H 5 ; e, c-C 6 H 11 ), which feature phosphines that are more electron rich and/or bulkier than P(C 6 H 5 ) 3 , are elaborated by reactions with HBF 4 ‚OEt 2 /chlorobenzene, HCtCH or HCtCCtCSiMe 3 , and t-BuOK to give the alkynyl complexes (η 5 -C 5 Me 5 )Re(NO)-(PR 3 )(CtCH) (3b,c) and (η 5 -C 5 Me 5 )Re(NO)(PR 3 )(CtCCtCSiMe 3 ) (7b-e). The latter are converted (K 2 CO 3 /MeOH or wet n-Bu 4 N + F -) to butadiynyl complexes (8b-e). Homo-or crosscouplings (3b, 8b-e; Cu(OAc) 2 /pyridine) lead to the µ-butadiynediyl complex (η 5 -C 5 Me 5 )Re-(NO)(PR 3 )(CtC) n (R 3 P)(ON)Re(η 5 -C 5 Me 5 ) (4b; n ) 2) and analogous µ-hexatriynediyl (10b; n ) 3) and µ-octatetraynediyl (9b-e; n ) 4) species. Oxidation of 4b by AgSbF 6 (ca. 1:1 or 1:2) gives the radical cation 4b •+ SbF 6or the dication 4b 2+ (SbF 6 -) 2 . These isolable compounds exhibit delocalized mixed-valence and cumulenic electronic ground states, respectively. The cyclic voltammograms of 9b-e and 10b show oxidations to analogous species, with much better chemical reversibilities than for the P(C 6 H 5 ) 3 analogues. However, these longer chain systems decompose rapidly at -78 °C and could not be isolated or spectroscopically characterized.

in Wiley InterScience (www.interscience.wiley.com).2-(1-Aryl-ethylidene)-malononitriles 1a-d undergo self dimerization in ethanol catalyzed by sodium ethoxide to afford 2-[4,6-diaryl-3-cyano-6-methyl-5,6-dihydropyridin-2(1H)-ylidene]-malononitrile derivatives 3a-d, respectively. The structure of the dimer was elucidated by X-ray crystallography and a plausible mechanism for its formation is depicted. Compound 3a couples with arene diazonium salts 4a-d to afford the hydrazo derivatives 5a-d; and reacts with hydrazine hydrate and phenylhydrazine 6a,b to afford the pyrazolo [3,4-h]

in Wiley InterScience (www.interscience.wiley.com).2-Dimethylaminomethylene-3-oxo-N-phenylbutyramide 1 reacts with malononitrile 2a to afford the pent-2-enedioic acid 1-amide 5-phenylamide derivative 6, which could be cyclized to give the 6-methylpyridone derivative 7. Compound 1 reacts with cyanoacetamide 2b to afford the same pyridone 7 and with cyanothioacetamide 2c to afford the analogous pyridinethione 12.

Indane‐1,3‐dione 1 reacts with salicylaldehyde 5 and malononitrile 3 to afford 6‐amino‐7‐imino‐7H‐indeno‐[2′,1′:5,6]‐pyrano‐[3,4‐c]‐chromene 6, which could be transformed into the corresponding 7‐oxo derivative 7. 2‐(3‐Oxoindan‐1‐ylidene)‐malononitrile 10 couples with the diazonium salts 8, 14, and 15 to afford after cyclization the indeno‐[2,1‐c]‐pyridazine 13 and the indeno‐[2′,1′:3,4]‐pyridazino‐[1,6‐a]‐quinazoline derivatives 20 and 21, respectively.