The charge-transfer reaction of decamethyiferrocene, Fe(C5Me5)2, Fc*, and 7,7,8,8-tetracyano-p-quinodimethane, TCNQ, has been characterized. Three major reaction products of varying stoichiometry, conductivity, and magnetism are formed: a 1-D metamagnetic 1:1 salt, [Fc*]'+[TCNQ]*~; a paramagnetic [Fc*]2,+ [TCNQ]22"; 1:1 dimeric salt, [Fc*]2'+ [TCNQ]22"; and a conducting 1:2 salt of [Fc*]'+[TCNQ]2~composition. The crystal and molecular structures of the 1:1 paramagnetic dimeric and metamagnetic one-dimensional salts were solved. The ions in the dimeric phase crystallize in the centrosymmetric monoclinic space group P2x/c with a = 9.708 (1) A, b = 12.211 (2) A, c = 23.585 (4) A, /? = 95.01 (1)°, Z = 4, and R = 0.058 for 3665 independent reflections. The structure consists of discrete stacks of DAAD dimeric (D = Fc*; A = TCNQ) units. One-dimensional stacking of ions is not observed. The decamethylferrocenium cations have average Fe-C distances of 2.096 (7) A, longer than the 2.050 A reported for neutral decamethyiferrocene. The C5Me5 rings appear eclipsed; however, as a result of the disorder only one ring was partially resolvable. The C5Me5 rings are essentially parallel to the TCNQ moieties and separated by 3.554 A. The TCNQ anions form a tight ag dimer (separated by a short distance of 3.147 A) and are slipped along the short TCNQ axis. Bonding arises through filling of the bonding ag dimer orbital. The magnetic susceptibility of powder samples of [Fc*]2,+[TCNQ2]22" obeys the Curie expression above 1.5 K suggesting very little magnetic coupling between the intradimer 5 = lJ2 Fe(III)'s which are separated by ~14 A. The [TCNQ]22" dimer is strongly antiferromagnetically coupled. The zero-field Mossbauer spectra of the dimeric phase above 1.4 K are typical of S' = '/2 [Fc*]'+ and exhibit rapidly relaxing paramagnetic behavior. However, relatively small external fields (<5 kG) are all that is necessary to induce slow paramagnetic relaxation and a substantial internal hyperfine field (~350 kG) at the decamethylferrocenium ions. Ions in the linear chain metamagnetic phase crystallize in the centrosymmetric triclinic space group PI. The unit cell at -106 °C is a = 8.635 (4) A, b = 9.384 (6) A, c = 10.635 (9) A; a = 116.76 (5)°, (3 = 112.58 (5)°; 7 = 72.49 (4)°, V = 701.8 A3, Z = 1, and Rv = 0.060 for 1156 reflections. The poorer quality of this structure is due to the inability to grow suitable crystals of this kinetically favored phase with respect to the thermodynamically favored dimeric phase. The structure consists of discrete one-dimensional chains comprised of alternating radical cation donors, D, and anion acceptors, A, i.e., -DADA-. The decamethylferrocenium cation has a staggered conformation with an average Fe-C distance of 2.090 A. This is equivalent to that observed for [Fc*]-+ in the dimeric phase. The C5Me5 rings are staggered and are canted with respect to the [TCNQ]'" moieties by 3.9°. The distance between the TCNQ and the C5Me5 rings is 3.43 A. The [TCNQ]"" anion represents the first structural character...

Metathetic reactions involving a variety of tungsten halides and LiNMe2 lead to W2(NMea)6, W(NMe2)e, and mixtures of these dimethylamides depending on the tungsten halides used. Pure W2(NMe2)é, free from W(NMe2)e, is prepared from the reaction of WCU with LiNMe2 (4 equiv). The related compounds W2(NMeEt)é and W2(NEt2)e are prepared by similar reactions. These tungsten(III) dialkylamides are pale-yellow, diamagnetic crystalline solids and have been characterized by a number of physical techniques including variable temperature NMR spectroscopy, infrared and Raman spectroscopy, and mass spectroscopy. Two compounds have been studied crystallographically. A substance consisting of W2(NMe2)s molecules and W(NMe2)é molecules in a 2:1 ratio crystallizes in the space group Pi, with unit cell dimensions: a = b = 13.556(2),_c = 9.420 (2) Á; V = 1499.6 (5) Á3. The W(NMe2)e molecule occupies the crystallographic position 0, 0, V2 with symmetry 3. The dimensions agree well with those previously determined for the pure W(NMe2)é phase. The W2(NMe2)6 molecules occupy the V3, %, z and %, V3, z positions with crystallographic symmetry 3. The W-W distance is 2.294 (1) Á; the mean W-N distance and mean W-W-N angles are, respectively, 1.98 Á and 103.8°. The structure was refined to R1 = 0.047 and T?2 = 0.061 using 4531 reflections having 7 > 3 ( ). Crystals consisting entirely of W2(NMe2)ó molecules belong to space group P2\/c (isomorphous with the corresponding Mo compound) with unit cell dimensions of a = 11.465 (3) Á, b = 11.948 (3) Á, c = 15.409 (3) Á, ß = 101.84 (2)°, and V = 2065.9 (8) Á3. There are two crystallographically independent molecules, each having crystallographic symmetry I but virtual symmetry which deviates only slightly from 3m (Du) and even less from 3 (Se). In these molecules the W-W distances are 2.290 (2) and 2.294 (2) Á. The mean values of the W-N distance and the W-W-N angles in both molecules are, respectively, 1.97 Á and 103.3°. This structure was refined to R¡ = 0.055 and T?2 = 0.067 using 1521 reflections having 7 > 3 (7).

The crystal and molecular structures of a compound of composition W2(CSiMe3)2(CH2SiMe3)4 have been determined. The compound consists of dinuclear molecules which contain bridging alkylidyne groups, CSiMe3, which, along with the tungsten atoms, form planar, rhombic rings, W-C-W-C. Two alkyl groups, CH2SiMe3, are attached to each metal atom to form distorted tetrahedra about the metal atoms. There are two crystallographically independent molecules, each residing on a crystallographic inversion center. The two crystallographically independent W-W distances, 2.521 (2) and 2.549 (2) Á, are consistent with the presence of W-W single bonds. The basic crystallographic data are as follows: space group P2Ja; unit cell dimensions a = 11.976 (4), b = 18.989 (5), c = 18.111 (5) Á; ß = 101.02 (2)°; V= 4043 (2) A3; Z = 4.

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