Synthesis and Chemistry of Dithiadiazole Free Radicals [4-(4′-C5H4N)CN2S2] and [4-(3′-C5H4N)CN2S2]; X-ray Crystal Structures of [Pd3{μ-SNC(Ar′)NS–S,S′}2(PPh3)4] (Ar′ = 4′-C5H4N, 4′-C5H4NBEt3 and 3′-C5H4NBEt3)

✍ Scribed by Wai-Kwok Wong; Chaode Sun; Wai-Yeung Wong; Daniel W. J. Kwong; Wing-Tak Wong

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 491 KB
• Volume: 2000
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/(sici)1099-0682(200005)2000:5<1045::aid-ejic1045>3.0.co;2-o

✦ Synopsis

Two new 1,2,3,5-dithiadiazoles, [4-(4Ј-C 5 H 4 N)CN 2 S 2 ] (L 1 ) and [4-(3Ј-C 5 H 4 N)CN 2 S 2 ] (L 2 ), with different pyridyl groups at the 4-position were prepared. As Lewis bases, the dithiadiazoles reacted with Lewis acids via their pyridyl groups to form acid-base adducts with retention of the five-membered dithiadiazole ring. Ligands L 1 and L 2 reacted with excess triethylborane to give L 1 BEt 3 and L 2 BEt 3 (1a and 1b) and with Mn(CO) 5 Br to give the fac-Mn(CO) 3 Br(L 1 ) 2 (2a) and fac-Mn(CO) 3 Br(L 2 ) 2 (2b) complexes. When reacted with Pd 0 complexes, namely, Pd(PPh 3 ) 4 and a mixture of [Pd 2 (dba) 3 ] and dppf, the dithiadiazoles underwent ring-opening reaction by reductive cleavage of the S-S bond of the dithiadiazole ring.