The class of “porcupine compounds”, includes the title cation 1, whose structure has been determined as the BPh4 salt. The analytically, mass‐spectrometrically and crystallographically detected interstitial C atom occupies the crystallographic inversion center in an octahedron composed of gold atoms: the structure is probably stabilized by AuċAu interactions. The periphery of tetraauriomethanes is apparently “aurophile” with respect to further LAu⊕ ions, so that the hypervalent complex cation [C(AuL)6]2⊕ is formed spontaneously. The supposedly uncentered octahedral cluster cations formulated previously as (AuL) 62⊕ were in fact probably indentical with the C‐centered species described here.

Laser induced breakdown spectroscopy (LIBS) is applied to analyze aqueous solutions of Li(+), Na(+), Ca(2+), Ba(2+), Pb(2+), Cd(2+), Hg(2+) and Er(3+) and suspensions of ErBa(2)Cu(3)O(x) particles (d=0.2 microm). An excimer (308 nm) pumped dye laser with laser pulse at 500 nm and pulse energy at 22+/-2 mJ is used to produce plasma in aqueous solution. Plasma emission lines of the elements are detected by a photodiode array detector. Detection limits of the metal ions are 500 mg/l for Cd(2+), 12.5 mg/l for Pb(2+), 6.8 mg/l for Ba(2+), 0.13 mg/l for Ca(2+), 13 microg/l for Li(+) and 7.5 microg/l for Na(+). No mercury and erbium emission can be detected, even at Hg(2+) and Er(3+) concentrations of up to the g/l range. On the other side, for Er in suspensions of ErBa(2)Cu(3)O(x) particles a more than 10(3) times higher sensitivity is found than for dissolved Er(3+). This result gives a possibility to analyze colloid-borne metal ions with an increased sensitivity.

No abstract

Sa: 'H NMR: 6 = 0.93 (d, J = 6.7 Hz, 3H, CH,-CH), 1.02 (s, 9H, fBu); 1.29 and 1.42(eachs,each3H,CH3-C-CH,);2.75and3.05(eachdoft, J = 4.9, 12.8 Hz. each 1 H, HO-C-CH,-), 2.06(s, 1H. OH), 3.36 (d of t. J = 4.0, 10.7 Hz, 1H. lCH-OR), 5.29 (s, lH, -S-CH-0). 7.15-7.28 (m, 4H, arom. H) 5 b : ' H N M R : d =0.92(d, J=6.4Hz,3H,CH3-CH);1.03(s,9H,rBu);1.29 and 1.44 (each s. je 3H, CH,-C-CH,); 2.59 and 3.09 (each d of I, J = 5.0, 13.1 Hz. each 1H. HO-C-CH,): 3.37 (s, l H , OH); 3.41 (d o f t , J =4.3, (c) VCH Verlagsgesell.~chaJt mhH. D-6940 Weinheim, 19x9 0870-0X33/89!0404-0464 $02.50/0 A n R m . Chrm. Int. Ed. En,qI. 2X (1989) N o . 4

The novel compound 1 contains three gold atoms attached to the same carbon atom. All three AuC distances are approximately equal. A further peculiarity: d10‐d10 interactions lead to Au‐Au distances of only ca. 3.2 Å; the tetrahedral angles AuCAu are correspondingly reduced to ca. 100°.