Synthesis, coordination chemistry, and metal complex reactivity of (dimethylamino)methyl-substituted triarylphosphanes; X-ray study on [AuCl(PPh3−nArn)] (Ar=1-C6H3(CH2NMe2)2-3,5, n=1, 3; Ar=1-C6H4(CH2NMe2)-4, n=3)
摘要:
The synthesis of the first series of 4-mono and 3,5-bis(dimethylamino)methyl-functionalized triarylphosphanes of the general formula PPh3-nArn (Ar = 1-C6H3(CH2NMe2)(2)-3,5 (NC(H)N), n = 1 (ligand 2) or n = 3 (ligand 4); Ar = 1 -C6H4(CH2NMe2)-4 (NC(H)), n = 3 (ligand 7)) is described. These phosphanes were used for the construction of complexes of the form [AuCl(P)] and [PtCl2(P)(2)]. In these complexes selective coordination of phosphorus to the metal ion is observed. The P-31 NMR data show the formation of cis-Pt complexes, even in the case of triarylphosphane 4, which features a tris{3,5-bis(dimethylamino)methyl} substitution pattern. The structure of the gold complex of mono-3,5-functionalized triarylphosphane 2 in the solid state shows a striking resemblance to the structure of the corresponding complex [AuCl(PPh3)]. The solid-state structure of the AuCl complex of tris-4-functionalized ligand 7 differs from that of [AuCl(PPh3)] in the sign of the torsion angles. The amine functionalities in this class of gold compounds could be reacted selectively with either acid (HCl, H3PO4) to generate ammonium salts or with an alkylating agent (benzyl bromide) to afford benzyl ammonium salts, without the violation of the Au-P bond. (c) 2005 Elsevier B.V. All rights reserved.
Design and synthesis of tris[bis(benzylammonium)aryl]phosphines with bulky meta-substituents
摘要:
A novel 3,5,3',5,3",5"-hexakis(dimethylamino)methyl substituted triphenylphosphine analogue has been prepared. The six amine functionalities of the corresponding phosphine oxide and sulfide were alkylated quantitatively with methyl iodide and benzyl bromide, as well as with G I and G2 Frechet dendrons to afford the respective hexa-ammonium triarylphosphine oxides and sulfides. The phosphine sulfide derivatives were deprotected with P(n-Bu)3 to afford a series of hexa-ammonium triarylphosphines that range from small molecules to first and second generation dendrimers (MW up to 5451.44). Upon formation of the hexa-ammonium salt a clear shift in P-31 NMR is observed, indicative for opening of the C-P-C angle of the triaryl phosphine. Calculations on the hexacationic phosphines show an increased barrier of rotation around the P-C(aryl) bond with increasing size of the N-substituents. The calculated structure of the G2-dendron alkylated hexa-ammonium triarylphosphine shows that this dendritic phosphine has a disc-like rather than a cone-like structure, with an estimated cone angle of approximately 180degrees (C) 2003 Elsevier Science Ltd. All rights reserved.