Bis-imidazol-Pd(II)-asetat komplekslerinin sentezi ve heck reaksiyonundaki uygulamaları
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Date
2012-07-24
Authors
Kaplan, Gökhan
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Publisher
Uludağ Üniversitesi
Abstract
Yeni bir yaklaşım ile 1,4-diaril-2,5-dihidro-1H-imidazolin 3-oksitler (1) sentezlenmiş ve bazik ortamda DMSO içinde 1,4-diaril-1H-imidazollere (2) dehidrate edilmiştir. 2 bileşiklerinin oda koşullarında Pd(OAc)2 ile (2:1 oranında) reaksiyonu sonucu cis- ve trans-1,4-diaril-1H-imidazol-Pd(II)-asetat (3) komplekslerinin karışımı oluşmuştur. Trans isomerlerin oda sıcaklığında cis isomerlere sübstitüente bağlı hızlarda dönüştükleri gösterilmiştir. Cis izomerler izole edilerek spektral ve analitik yöntemlerle karakterizasyonları yapılmıştır. X-ışını kırınımı yöntemiyle (3c örneğinde) tahmin edilen cis yapılar doğrulanmıştır. Sentezlenen Pd-komplekslerinin 3 model Heck reaksiyonunda katalitik aktiviteleri araştırılmış ve seçici yüksek TON lu katalizör oldukları belirlenmiştir.
A series of 1,4-diaryl-2,5-dihydro-1H-imidazole 3-oxides (1) were synthesized by a new approach and dehydrated to give imidazoles (2) in DMSO in the presence of a base. The reaction of imidazoles (2) with Pd(OAc)2 in dichloromethane at room temperature provides a mixture of cis- and trans- bis-1,4-diaryl-1H-imidazole-Pd(II)-diacetate complexes (3). The trans isomers were shown to convert to the corresponding cis isomer in a substituent dependent manner. Cis isomers were isolated and characterized by spectral and analytical methods. X-ray diffraction studies on (3c) confirmed the assigned cis structures.Catalytic activities of the isolated as well as in situ formed 1,4-diaryl-1H-imidazole-Pd(II)-diacetate complexes (3) were investigated in model Heck reactions. The newly prepared complexes served as high turnover number catalysts.
A series of 1,4-diaryl-2,5-dihydro-1H-imidazole 3-oxides (1) were synthesized by a new approach and dehydrated to give imidazoles (2) in DMSO in the presence of a base. The reaction of imidazoles (2) with Pd(OAc)2 in dichloromethane at room temperature provides a mixture of cis- and trans- bis-1,4-diaryl-1H-imidazole-Pd(II)-diacetate complexes (3). The trans isomers were shown to convert to the corresponding cis isomer in a substituent dependent manner. Cis isomers were isolated and characterized by spectral and analytical methods. X-ray diffraction studies on (3c) confirmed the assigned cis structures.Catalytic activities of the isolated as well as in situ formed 1,4-diaryl-1H-imidazole-Pd(II)-diacetate complexes (3) were investigated in model Heck reactions. The newly prepared complexes served as high turnover number catalysts.
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Keywords
Nitronlar, İmidazoller, Cis-Pd(II)-imidazol kompleksleri, Heck reaksiyonu, Nitrones, Imidazoles, Cis-Pd(II)-imidazole complexes, Heck reaction
Citation
Kaplan, G. (2012). Bis-imidazol-Pd(II)-asetat komplekslerinin sentezi ve heck reaksiyonundaki uygulamaları. Yayınlanmamış yüksek lisans tezi. Uludağ Üniversitesi Fen Bilimleri Enstitüsü.