| Abstrakt: |
The reaction of 1,3-bis(2-pyridyl)benzene, N∧CH∧N, with H[AuCl4] has been studied under different conditions.Mono- ([N∧CH∧NH][AuCl4]) and di-protonated salts ([HN∧CH∧NH][AuCl4]2), as well as an adduct, [(N∧CH∧N)(AuCl3)2], have been isolated. Very rare cyclometalated pincer derivatives, [Au(N∧C∧N)Cl]+ have been obtained as different salts, either by transmetallation from the corresponding mercury(II) derivative, [Hg(N∧C∧N)Cl], or by direct C-H activation. The structures in the solid state of [N∧CH∧NH][AuCl4] and [Au(N∧C∧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∧C∧N)(Cl)(PPh3)2]+, [Au(N∧C∧N)(Cl)(dppm)2]+ and [Au(N∧C∧N)(Cl)(dppe)]+, respectively. The X-ray structure of [Au(N∧C∧N)(Cl)(PPh3)2][PF6] confirms that the ligand N∧C∧N is only s-carbon bonded and the PPh3 molecules are in a trans-arrangement. The pattern of the 31P{1H}NMR spectrum of [Au(N∧C∧N)(Cl)(dppm)2]+, a pair of "triplets", deserves comments: the spectrum is not of the A2X2 type but a case of a deceptively simple AA'XX' spin system. [ABSTRACT FROM AUTHOR] |
