Organometallic compounds of the lanthanides. 36. Bis(pentamethylcyclopentadienyl) halide and alkyl derivatives of the lanthanides

Greatly reduced radiation damage in ribonuclease crystals mounted on glass fibers

“…Further attempts to overcome the frosting problem led us to a technique that we, and others, have used to collect data from crystals of small-molecule compounds that are air/ moisture sensitive (Hope, 1985;Listemann, Dewan & Schrock, 1985;Chisholm, Huffman & Smith, 1986;Schumann, Albrecht, Loebel, Hahn, Hossain & van der Helm, 1986) or that rapidly lose solvent of crystallization upon removal from the mother liquor (Hope, 1985;Pedersen, Dewan & Sharpless, 1986). The latter case is not at all dissimilar to the problem encountered with protein crystals.…”

Lutetium gets a crown: Synthesis, structure and reaction chemistry of the separated ion pair complex, [Li(12-crown-4)2][(C5Me5)2LuMe2]

“…The structure of complex 2 has not been reported and earlier reports were inconclusive as to whether it was a bis(tetrahydrofuran) [38] or tris(tetrahydrofuran) [48] complex. We were able to obtain single crystals of 2 suitable for X-ray crystallography from a concentrated diethyl ether solution at À35 C. The molecular structure of (C 5 Me 5 ) 2 Lu(Me)(m-Me)Li(THF) 3 (2) is shown in Fig.…”

“…Although this classic lanthanide system exists as the "ate" complexes (C 5 Me 5 ) 2 Lu(mMe) 2 Li(THF) 2 and (C 5 Me 5 ) 2 Lu(m-Me) 2 Li(tmeda) with bridging metal groups, it shares structural and chemical similarities with known bis(cyclopentadienyl) transition-metal bis(alkyl) complexes [37]. For example, (C 5 Me 5 ) 2 Lu(m-Me) 2 Li(THF) 2 features a tetrahedral bent-metallocene geometry around the lutetium metal center and participates in protonolysis chemistry with alcohols and thiols to yield alkoxide and thiolate complexes [38,39]. The bentmetallocene platform is known to support numerous actinide and transition metal multiple bonds; however, (C 5 Me 5 ) 2 Lu(mMe) 2 Li(THF) 2 exists as a contact-ion pair complex with bridging methyl groups.…”

“…The reaction mixture was filtered through a medium-porosity fritted filter to collect an off-white powder, which was washed with Et 2 O (2 x 5 mL), pentane (2 x 10 mL), and dried under reduced pressure to give Na(C 5 Me 5 ) as an off-white powder (9.52 g, 60.2 mmol, 87%). 1 This is a slight modification to a literature procedure [38]. A 125-mL side-arm flask was charged with a stir bar, Na(C 5 Me 5 ) (2.50 g, 15.8 mmol) and THF (25 mL).…”

“…A summary of the crystallographic data and details of the structure refinements are listed in Table 1. An obvious starting material for the preparation of the separated ionepair complex [Li(12-crown-4) 2 ][(C 5 Me 5 ) 2 LuMe 2 ] (3) was the known methyl-bridged lutetium complex (C 5 Me 5 ) 2 Lu(mMe) 2 Li(THF) 2 , which was originally made by the reaction of LuCl 3 with Na(C 5 Me 5 ) in THF at room temperature for two days, followed by addition of MeLi in Et 2 O at À78 C [38]. We find that the addition of MeLi can be performed at room temperature.…”