Synthesis of Luminescent Alkynyl Gold Metalaligands Containing 2,2′-Bipyridine-5-yl and 2,2′:6′,2′′-Terpyridine-4-yl Donor Groups

[AuCl(SMe 2 )] reacts with HC≡CR (R = bpyl = 2,2′-bipyridine-5-yl ( 1 ), phtpyl = phenyl-4-(2,2′:6′,2′′-terpyridine-4-yl) ( 2 )) and NEt 3 (1:1:3) to afford the polymers [Au(C≡CR)] n (R = bpyl ( 3 ), phtpyl ( 4 )). The new alkyne HC≡Cphccbpyl ( 5, phccbpyl = 4-C 6 H 4 C≡Cbpyl) has been prepared by Sonogashira coupling of 4-Me 3 SiC≡CC 6 H 4 I and 1 followed by desilylation of the resulting alkyne 4-Me 3 SiC≡Cphccbpyl. The alkynyl Au(I) complexes [Au(C≡CR)L] (R = bpyl, L = PPh 3 ( 6 ), PTol 3 ( 7, Tol = 4-MeC 6 H 4 ), PEt 3 ( 8 ); R = phtpyl, L = XyNC ( 9 ), PPh 3 ( 10 ); R = phccbpyl, L = PPh 3 ( 11 )) have been prepared by reacting: (1) 3 or 4 with L or (2) the corresponding alkyne 1, 2, or 5 with [Au(acac)(PPh 3 )] (acac = acetylacetonato). The reaction of 3 or 4 with diphosphines gives [{Au(C≡CR)} 2 (μ-Ph 2 P(CH 2 ) x PPh 2 )] (R = bpyl, x = 1 ( 12 ), 2 ( 13 ), 4 ( 14 ), 10 ( 15 ); R = phtpyl, x = 10 ( 16 )). ESI mass spectrometric studies show that complexes 12 – 14 are in equilibrium with the salts [Au 3 (C≡Cbpyl) 2 (μ-Ph 2 P(CH 2 ) x PPh 2 ) 2 ][Au(C≡Cbpyl) 2 ], although only when x = 1 ( 17 ) was a significant concentration of the salt detected by NMR spectroscopy and isolated. The anionic complexes PPN[Au(C≡CR) 2 ] (R = bpyl ( 18 ), phtpyl ( 19 ), or phccbpyl ( 20 )) have been prepared by reaction of the corresponding alkynes with PPN[Au(acac) 2 ]. Complexes 6, 10, 13, 14, 17, and 18 have been characterized by single-crystal X-ray diffraction studies. The alkynyl complexes are luminescent at room temperature, displaying dual emissions.