Systematic method for the incorporation of the {(eta(6)-arene)Fe} fragment into carborane cages via [(eta(6)-arene)Fe]2+ dications. A series of [3-(eta(6)-arene)-closo-3,1,2-FeC2B9H11] complexes. Reliable synthesis of polymethylated [(eta(6)-arene)2Fe]2+ cations.

Developed was a systematic method for the incorporation of the {(eta(6)-arene)Fe} fragment into a carborane cage. Reactions between [(eta(6)-arene)(2)Fe](PF(6))(2) salts and Tl(2)[nido-7,8-C(2)B(9)H(11)] in refluxing (CH(2))(2)Cl(2) generated a series of [3-(eta(6)-arene)-closo-3,1,2-FeC(2)B(9)H(11)] neutral complexes with variable types of polymethylated arene ligands in the structure. The structures of durene and hexamethylbenzene complexes were established by X-ray diffraction analyses. The work also shows that the original high-temperature method for the preparation of the [(eta(6)-arene)(2)Fe](2+) dications fails for mesitylene and durene compounds, which was overcome by a reliable room-temperature modification.

Phosphacarborane chemistry: the 7,8,9,11-, 7,9,8,10- and 7,8,9,10-isomers of nido-P2C2B7H9--diphosphadicarbaborane analogues of 7,8,9,10-C4B7H11.

The reaction between the carborane arachno-4,6-C2B7H13 (1) and PCl3 in dichloromethane in the presence of a "proton sponge" (PS = 1,8-dimethylaminonaphthalene) resulted in the isolation of the eleven-vertex nido-diphosphadicarbaboranes 7,8,9,11-P2C2B7H, (2) and 3-Cl-7,8,11-P2C2B7H, (3-Cl-2) in yields of 54 and 7%, respectively. Replacement of the PS by NEt3 in the same reaction gave diphosphadicarbaboranes 2 and 3-CI-2 together with the isomeric species nido-7,9,8,10-P2C2B7H, (3) in yields of 28, 15 and 3%, respectively. The reaction between the isomeric carborane arachno-4,5-C2B7H13 (4) and PCl3 in dichloromethane in the presence of PS gave the asymmetrical isomer, nido-7,8,9,10-P2C2B7H, (5). along with the chloro derivatives 4-Cl-7,8,9,10-P2C2B7H8 (4-Cl-5) and 11-Cl-7,8,9,10-PC2B7,H8 (11-Cl-5) (yields of 21, 1 and 13%, respectively). The structures of the chlorinated derivatives 3-Cl2 and 11 -Cl-5 were determined by X-ray diffraction analysis. In addition, the structures of all compounds isolated were geometry-optimised and confirmed by comparison of experimental 11B chemical shifts with those calculated by the GIAO-SCF/II//RMP2(fc)/6-31G* method. The calculations also include the structure and 11B NMR shifts of the isomer nido-7,10,8,9-P2C2B7H9 (6) which has not yet been isolated.

Ten-vertex rhodadithiaborane chemistry:.

Neutral 8-(5-iodo-n-pentyl)-3-(eta(5)-pentamethylcyclopentadienyl)-arachno-3-rhoda-7,8-dithiaundecaborane, [Rh(C(5)H(19)B(8)IS(2))(C(10)H(15))], obtained from the [arachno-7,8-S(2)B(9)H(10)](-) anion by treatment with I(CH(2))(5)I followed by [Rh(C(5)Me(5))Cl(2)](2) and N,N,N',N'-tetramethyl-1,8-diaminonaphthalene, has the 11-vertex cluster geometry of [arachno-7,8-S(2)B(9)H(10)](-), but with an [Rh(C(5)Me(5))] unit in the 3-position instead of a [BH] unit, and with a -(CH(2))(5)I chain attached exo to an S atom.

Monocarbaborane chemistry. Preparation and characterisation of [4-CB8H9]-, the 'missing' closo-carbaborane anion.

Thermolysis in the solid state of Cs+[arachno-CB9H14]-, or of Cs+[nido-CB9H12]-, or the oxidation of nido-1-CB8H12 with I2 in THF at -78 degrees C in the presence of NEt3, gives the first nine-vertex closo monocarbaborane, the stable [closo-4-CB8H9]- anion, in yields of 56, 61 and 75%, respectively.

[1,1,2,2-]

The title compound, 1,1,2,2-tetracarbonyl-1,2-&mgr;-carbonyl-4, 11-dimethylsulfido-closo-1,2-dicobaltadodecaborane, [Co(2)(C(4)H(20)B(10)S(2))(CO)(5)], has a closo 12-vertex 1, 2-Co(2)B(10)H(8) structure with SMe(2) ligands at the exo-4- and 11-positions. The cluster displays close structural similarities to the SEt(2) analogue.

Unusual 9-->10 rearrangement of the substituted cage carbon in the ferratricarbollide series. Synthesis of the isomeric complexes [2-eta 5-(C5H5)-10-X-closo-2,1,7,10-FeC3B8H10] (where X = H2N, MeHN, Me2N, and ButHN).

Treatment of the zwitterionic amine tricarbollides of general formula 7-L-nido-7,8,9-C3B8H10 (1) (where L = Me2HN (1c) and ButH2N (1d)) with [(eta 5-C5H5)Fe(CO)2]2 in refluxing mesitylene resulted in the formation of a mixture of the known compounds [2-(eta 5-C5H5)-9-X-closo-2,1,7,9-FeC3B8H10] (2) (where X = H2N (2a), Me2N (2c), and ButHN (2d)) and a series of new, isomeric ferratricarbollylamines [2-(eta 5-C5H5)-10-X-closo-2,1,7,10-FeC3B8H10] (3) (where X = H2N (3a), Me2N (3c), and ButHN (3d)) in moderate yields. Complexes of type 3 (where X = H2N (3a), MeHN (3b), Me2N (3c), and ButHN (3d)) were also obtained readily by heating complexes of type 2 (where X = H2N (2a), MeHN (2b), Me2N (2c), ButHN (2d), and Bu(t)(Me)N (2e)) at ca. 300 degrees C for 10 min. All the complexes of type 3 contain reactive amine functions in meta positions with respect to the metal center. The observed 9-->10 rearrangement of the substituted cluster carbon is quite unexpected and is believed to result from higher thermodynamic stability of the 10-substituted isomers. The structures of all compounds of type 3 were established by high-field NMR spectroscopy and mass spectrometry, and that of 3d was determined by an X-ray diffraction study.

[Use of electrodense metals in transmission electron microscopy technology]. / Nové moznosti aplikace elektrodenzních kovu pro technologii transmisní elektronové mikroskopie.

Metalloboranes could serve perspectively as carriers of electrodense metals for electron microscopy, because they penetrate into tissues and are linked to them. The tested brominated cobaltacarborane anion, however, did not by far meet the demands of standard quality electronograms, as in combination with aldehyde fixation they give a low contrast of protein and nucleoprotein structures and contrary to osmium tetroxide they does not mark membrane lipids; it did not prove useful for contrasting of epoxide sections. The results, however, stimulate the seeking of more suitable boranes substituted with metals with a higher atomic number and a different molecular configuration.