Furfuryl alcohol can be transformed in a simple way into the long‐awaited sulfur analog of porphyrin, the tetrathiaporphyrin dication 1, isolated as the perchlorate. The key to the synthesis is a remarkably straightforward sulfur/oxygen exchange in tetraoxaporphyrinogen. As would be expected from the relatively large van der Waals radius of sulfur, the transformation from the tetraoxaporphyrin dication to 1 is accompanied by loss of planarity in the ring system.

7] Crystallographic data for 2 . 3py (C,,H,,CI,LiN,, M = 328.16): Monoclinic, space group P2,ln, a=1271.3(1). b =1072.8(5), c =1273.1(1)pm, / 3 = 91.81(1Y. V=1735.5(8)x 10-30m3. 2 = 4. p ,, =1.256 Mgm-'. ~(CU,,) = 3.331 mm". Data collection on an Enraf-Nonius CAD4 diffractometer with graphite monochromated Cu,, -radiation. o scans. max. 12 s per reflection, T = 150(2) K. 2604 reflections were collected (4 < 0 i 55"). of which 2185 were unique (R,,, = 0.053). The structure was solved with direct methods (SHELXTL) and was refined on F2 with all reflections (SHELXL-93). non-hydrogen atoms anisotropic, hydrogen atoms (without Hl) on calculated positions with fixed isotropic temperature factors. The parameters of the weightingschemecalculated by the program were: 0.1150,2.3053, wR2(Rl for 1949 reflections with I > Zu(1)): 0.2051 (0.0740), Goof =1.033; 204 refined parameters. The data were corrected with the program DIFABS ( R values without the DIFABS correction: 0.2283.0.0834). Relatively high temperature factors for the atoms C9 and C10 and "too short" bond lengths C8-C9 and C9-C10 indicate disorder which has not been resolved [13]. All calculations have been performed on an Micro-VAX I1 and a Dec 3000-300X [8-121 [8] Siemens SHELXTL (VMS) Vers. 5.04, Siemens-Analytical-X-Ray-lnstru-

ZUSCHRIFTENAutoren, die e k e ,,Zuschrift" veroffentlichen wollen, soliten vor der Abfassung ihres Manuskripts unbedingt die ,,Hinweise f i r Autoren" lesen, die jeweils im Januarheft eines Jahrgangs nach dem Inhaltsverzeichnis gedruckt sind; auf Anforderung konnen sie auch von der Redaktion erhalten werden.

geometry of the copper complex (Fig. 3a).ii3f Moreover. the EPR spectrum is indicative of a type-I1 copper binding site in a similar ligdnd environment with g , , = 2.27 and A , , = 173 (cm-x lo4). Peisach and Blumberg analysis[141 is

Als Modellverbindung in der Thiaporphyrin‐Reihe empfiehlt sich aufgrund guter Löslichkeit das Dikation 1 (als Perchlorat). Schlüsselschritt der Synthese von 1 ist die säureinduzierte Kondensation (nicht biomimetisch!) von 3,4‐Diethyl‐2‐hydroxymethylthiophen, die außer dem Tetra‐ auch das Pentacyclokondensationsprodukt liefert. Letzteres eröffnet den Weg zum 22π‐Pentathiapentaphyrin‐Trikation 2, dem Schwefelanalogon von Pentaphyrin.