Reactivity of 1,3-bis(2-pyridyl)benzene, N boolean AND CH boolean AND N, with gold(III) chlorides: salts, adducts and cyclometalated pincer derivatives. Crystal and molecular structures of [HN boolean AND CH boolean AND N][AuCl4], [Au(N boolean AND C boolean AND N)Cl][PF6] and [Au(N boolean AND C boolean AND N)Cl(PPh3)(2)][PF6]

摘要

The reaction of 1,3-bis(2-pyridyl)benzene, N boolean AND CH boolean AND N, with H[AUCl(4)] has been Studied under different conditions. Mono- ([N boolean AND CH boolean AND NH][AuCl4]) and di-protonated salts ([HN boolean AND CH boolean AND NH][AuCl4](2)), as well as an adduct, [(N boolean AND CH boolean AND N)(AuCl3)(2)], have been isolated. Very rare cyclometalated pincer derivatives, [Au(N boolean AND C boolean AND N)Cl](+) have been obtained as different salts, either by transmetallation from the corresponding mercury(ii) derivative, [Hg(N boolean AND C boolean AND N)Cl], or by direct C-H activation. The structures in the solid state of [N boolean AND CH boolean AND NH][AuCl4] and [Au(N boolean AND C boolean AND N)Cl][PF6] have been solved by X-ray diffraction. Reaction of the pincer derivatives with PPh3, dppm (bis(diphenylphosphino)methane) and dppe (1,2-bis(diphenylphosphino)ethane) occurs with displacement of the coordinated nitrogen atoms to afford [Au(N boolean AND C boolean AND N)(Cl)(PPh3)(2)](+), [Au(N boolean AND C boolean AND N)(Cl)(dppm)(2)](+) and [Au(N boolean AND C boolean AND N)(Cl)(dppe)](+), respectively. The X-ray structure of [Au(N boolean AND C boolean AND N)(Cl)(PPh3)(2)][PF6] confirms that the ligand N boolean AND C boolean AND N is only sigma-carbon bonded and the PPh3 molecules are in a trans-arrangement. The pattern of the P-31{H-1}NMR spectrum of [Au(N boolean AND C boolean AND N)(Cl)(dppm)(2)](+), a pair of "triplets", deserves comments: the spectrum is not of the A(2)X(2) type but a case of a deceptively simple AA'XX' spin system.