A Series of the Twelve-Vertex Ferratricarbollides [2-(η 5 -C 5 H 5 )-9-X-closo-2,1,7,9-FeC 3 B 8 H 10 ] (Where X ) H 2 N, MeHN, Me 2 N, Bu t HN, Bu t (Me)N). A Highly Stable Metallatricarbaborane System with Amine Functions in the Para Position to the Metal Center Josef Holub, † Bohumı ´r Gru 1 ner, †,‡ Ivana Cı ´sar ˇ ova ´ , § Jir ˇ ı ´ Fusek, † Zbyne ˇ k Plza ´ k, † Francesc Teixidor, ‡ Clara Vin ˜ as, ‡ and Bohumil S ˇ tı ´br* ,† Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, 250 68 R ˇ ez ˇ, Czech Republic, Faculty of Natural Sciences of Charles University, Hlavova 2030, 128 42 Prague 2, Czech Republic, and Institute of Material Sciences, CSIC, Campus UAB, 08193 Bellaterra, Spain ReceiVed December 8, 1998 Treatment of the zwitterionic amine tricarbollides of general formula 7-XH-nido-7,8,9-C 3 B 8 H 10 (1) [X ) H 2 N (1a), Me 2 N(1b), Bu t HN (1c), Bu t (Me)N (1d)] with [(η 5 -C 5 H 5 )Fe(CO) 2 ] 2 in refluxing xylene for 24 h resulted in the formation of a series of new mixed-sandwich metallatricarbollides [2-(η 5 -C 5 H 5 )-9-X-closo-2,1,7,9-FeC 3 B 8 H 10 ] (2) [X ) H 2 N(2a), Me 2 N(2b), Bu t HN (2c), Bu t (Me)N (2d)] in yields 16-54%. The reaction of 1d is associated with partial loss of isobutylene and formation of the 9-MeHN-derivative 2e. Derivatives 2a and 2c were also isolated from reactions between the thallium salts Tl + [7-X-nido-7,8,9-C 3 B 8 H 10 ] - (Tl + 1 - ) [X ) H 2 N (Tl + 1a - ), BuH t N (Tl + 1c - )] and [(η 5 -C 5 H 5 )Fe(CO) 2 I] in refluxing toluene (yields 38 and 55%, respectively). All complexes of type 2 contain amine functionalities in para-positions with respect to the metal center, the complexation being in all cases associated with an extensive rearrangement of the cluster carbons into positions of maximum separation. The structures of all compounds were established by high-field NMR spectroscopy and mass spectrometry, and that of 2c was determined by an X-ray diffraction study. Introduction We have recently reported the synthesis of the ligand derivatives of general formula 7-L-nido-7,8,9-C 3 B 8 H 10 (where L ) amines), 1 which are zwitterionic derivatives of the parent 2 tricarbollide anion [nido-7,8,9-C 3 B 8 H 11 ] - . Metallacarborane chemistry of these eleven-vertex tricarbaboranes (tricarbollides) has so far been restricted to the complexation of the Tl + salt of the latter anion with [(η 5 -C 5 H 5 )Fe(CO) 2 I] in refluxing toluene under the formation of the unsubstituted complex [2-(η 5 -C 5 H 5 )- closo-2,1,7,10-FeC 3 B 8 H 11 ], while a similar reaction of the isomeric [7,8,10-C 3 B 8 H 11 ] - anion resulted in boron removal to give the eleven-vertex species [1-(η 5 -C 5 H 5 )-closo-1,2,3,4- FeC 3 B 7 H 10 ]. 3 As there is a good precedent for metal complex- ation of the zwitterionic amine monocarbaboranes containing at least one acidic hydrogen on the ligand nitrogen, 4 it was surmised that the analogous tricarbaborane counterparts would display similar behavior. This presumption became correct and we report here two simple procedures leading to smooth rearrangement complexation of compounds of type 1 to produce a series of new metallatricarbollide isomers that contain chemi- cally flexible amine functionalities in p-positions with respect to the metal center and are isomeric with the unsubstituted complex [2-(η 5 -C 5 H 5 )-closo-2,1,7,10-FeC 3 B 8 H 11 ] previously reported. 3 Experimental Section General Procedures. All reactions were carried out with use of standard vacuum or inert-atmosphere techniques as described by Shriver, 5 although some operations, such as preparative TLC, were carried out in air. The starting compounds of type 1 were prepared according to the literature. 1 The Fluka hexane, benzene, toluene, and dichloromethane were dried over CaH2 and freshly distilled before use. Other chemicals were reagent or analytical grade and were used as purchased. Preparative TLC was carried out using silica gel G with a fluorescent indicator (Aldrich, type UV 254) as the stationary phase on plates of dimensions 200 × 200 × 1 mm, made on glass formers from aqueous slurries followed by drying in air at 80 °C. The purity of individual chromatographic fractions was checked by analytical TLC on Silufol (silica gel on aluminum foil; detection by diiodine vapor, followed by 2% aqueous AgNO3 spray). Melting points were measured in sealed capillaries under nitrogen and are uncorrected. Low resolution mass spectra were obtained using a Finnigan MAT Magnum ion trap quadrupole mass spectrometer equipped with a heated inlet option, as developed by Spectronex AG, Basle, Switzerland (70 eV, EI ionization). Proton ( 1 H) and boron ( 11 B) NMR spectroscopies were performed at 7.05 and 11.75 T on Bruker ARX 300 and Varian UNITY 500 instruments, respectively. The [ 11 B- 11 B] COSY 6 and 1 H{ 11 B(selective)} 7 NMR experiments were essentially as described in other related papers * Corresponding author. Fax: +42 02 2094 1502. E-mail: stibr@ uachr.iic.cas.cz. † Institute of Inorganic Chemistry. ‡ Institute of Material Sciences. § Charles University. (1) (a) S ˇ tı ´br, B.; Holub, J.; Teixidor, F.; Vin ˜as, C. J. Chem. Soc., Chem. Commun. 1995, 795-796. (b) S ˇ tı ´br, B.; Holub, J.; Cı ´sar ˇova ´, I.; Teixidor, F.; Vin ˜as, C.; Fusek, J.; Plza ´k, Z. Inorg. Chem. 1996, 35, 3635-3642. (c) S ˇ tı ´br, B.; Holub, J.; Teixidor, F. AdVances in Boron Chemistry; Siebert W., Ed.; Royal Society: London, 1997; pp 333- 340. (2) Holub, J.; S ˇ tı ´br, B.; Hnyk, D.; Fusek, J.; Cı ´sar ˇova ´, I.; Teixidor, F.; Vin ˜as, C.; Plza ´k, Z.; Schleyer, P. v. R. J. Am. Chem. Soc. 1997, 119, 7750-7759. (3) S ˇ tı ´br, B.; Holub, J.; Teixidor, F.; Vin ˜as C. Collect. Czech. Chem. Commun. 1995, 60, 2023-2027. (4) Knoth, W. H.; Little, J. L.; Lawrence, J. R.; Scholer, F. R.; Todd, L. J. Inorg. Synth. 1968, 11, 33-45. (5) Shriver, D. F.; Drezdon, M. A. Manipulation of Air-SensitiVe Compounds, 2nd ed.; Wiley: New York, 1986. 2775 Inorg. Chem. 1999, 38, 2775-2780 10.1021/ic981400e CCC: $18.00 © 1999 American Chemical Society Published on Web 05/15/1999