Heteroligand and heteronuclear clamshell-type phthalocyanines: selective preparation, spectral properties, and synthetic application Alexander Yu. Tolbin a,b,*,  , Victor E. Pushkarev b,  , Gennadiy F. Nikitin a , Larisa G. Tomilova a, * a Moscow State University, Chemistry Department, Moscow, Russia b Institute of Physiologically Active Compounds RAS, Chernogolovka, Moscow region, Russia article info Article history: Received 2 March 2009 Revised 19 May 2009 Accepted 5 June 2009 Available online 13 June 2009 abstract A direct synthetic method to produce heteronuclear and heteroligand clamshell-type binuclear phthalo- cyanines via a nucleophilic coupling reaction between A 3 B-type monophthalocyanines is developed with the target compounds demonstrating the possibility to form sandwich-type heterocomplexes for the first time. Ó 2009 Elsevier Ltd. All rights reserved. Binuclear phthalocyanines have become the subject of intensive research owing to their unique spectral and electrochemical properties resulting from a multicircuit-conjugated p-electronic system. 1–3 Significant attention has been paid to binuclear phthal- ocyanines bridged through rigid spacers (clamshell-type). Such bridges provide a specific geometry resulting in the macrocycles having a cofacial conformation in solution. 4 Clamshell-type metall- ophthalocyanines are both unique catalysts of biochemical processes 1,5 and components of ion-selective electrodes 6 for recog- nition of bifunctional organic molecules. Varying the nature of the complexing metals, as well as of the peripheral substituents, allows the selectivity of such recognition to be increased and wid- ens appreciably the range of molecules under investigation. In this connection, the development of direct approaches to heteroligand and heteronuclear clamshell-type phthalocyanines is an important task. Recently, we developed a selective method for preparing homo- nuclear clamshell-type phthalocyanines. 7 We now describe a new approach to heteroligand and heteronuclear clamshell-type phthal- ocyanines based on nucleophilic coupling of functionalized unsym- metrically substituted monophthalocyanines. TMS-protection of phthalogen 1 8 followed by cyclization of the isolated TMS-derivative with 4-tert-butylphthalonitrile (2) 9,10 in the presence of CH 3 OLi in n-hexanol gave unsymmetrically substi- tuted monophthalocyanine 3a 11 after removal of the TMS-group using AcOH. Analogues have been described earlier, for example, zinc complex 3b, 12 but the yields were poor. Reaction of phthalo- cyanines 3a, b with TsCl gave the corresponding tosylates 4a, b 13 (Scheme 1). N N N N N N N N O OX CN CN O 1 OH i, ii, iii 3a,b a:R 1 =H ( t Bu), R 2 = t Bu (H), M=2H, X=H (52%) b:R 1 =R 2 =OPr n , M=Zn, X=H iv M R 1 R 2 R 1 R 2 R 1 R 2 4a,b a:R 1 =H ( t Bu), R 2 = t Bu (H), M=2H, X=Ts (88%) b:R 1 =R 2 =OPr n , M=Zn, X=Ts (79%) Scheme 1. The synthesis of starting tosyl derivatives 4a, b. Reagents: (i) [(CH 3 ) 3 Si] 2 NH/THF, (CH 3 ) 3 SiCl, 30 min; (ii) 4-tert-butylphthalonitrile (2), CH 3 OLi/ n-C 6 H 13 OH, 4 h; (iii), AcOH/H 2 O; (iv) NaH/DMF, TsCl, 8 h. 0040-4039/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.tetlet.2009.06.048 * Corresponding authors. Tel.: +7 495 9391243; fax: +7 495 9390290. E-mail address: tolbin@newmail.ru (A.Yu. Tolbin).   Tel./fax: +7 496 5249508. Tetrahedron Letters 50 (2009) 4848–4850 Contents lists available at ScienceDirect Tetrahedron Letters journal homepage: www.elsevier.com/locate/tetlet