The First Copper Complexes Bearing the 1,3,5‐Triaza‐7‐phosphaadamantane (PTA) Ligand

Abstract

The CuI compound [Cu(PTAH)4](NO3)5 (1) {PTAH = N‐protonated form of 1,3,5‐triaza‐7‐phosphaadamantane (PTA)} was easily prepared by reacting hydrated Cu(NO3)2 and PTA in aqueous acidic solution at room temperature. Further treatment of 1 with sodium hydroxide in water led to an unprotonated PTA derivative [Cu(PTA)4](NO3) (2). Both compounds are water‐soluble and air‐stable, and were characterized by IR, 1H‐, 13C{1H}‐, 31P{1H}‐ and 63Cu NMR spectroscopy, FAB‐MS(+), elemental and single‐crystal X‐ray diffraction structural analyses. They exhibit a nearly regular tetrahedral coordination environment about each copper centre filled by the phosphorus atoms of the four PTAH/PTA moieties, which show distinct and unusual geometrical arrangements if viewed along the P–Cu bonds. The 31P{1H}‐ and 63Cu NMR spectra of 2 in D2O solution show spin coupling between the 31P and 63Cu nuclei at room temperature. These compounds represent the first examples of Cu complexes bearing PTA or any derived ligand with a cagelike PTA core and expand the restricted family of aqua‐soluble copper phosphane complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Synthesis and structural characterization of copper(I) complexes bearing N-methyl-1,3,5-triaza-7-phosphaadamantane (mPTA)

“…While a large variety of lipophilic Cu(I) phosphine complexes stable in classic organic media has already been reported [21] very few examples of water-soluble Cu(I) compounds stable to disproportionation in water are known. These comprise the polymeric {Na 5 [23,24]. Other recent water soluble Cu(I) derivatives present a mixed coordination sphere with a monodentate tertiary phosphine and a tripodal scorpionate ligand [12,[25][26][27].…”

“…The syntheses were carried out in acetonitrile at room temperature and consist of a ligand-exchange reaction between the labile acetonitrile molecules of [Cu(CH 3 CN) 4 5 , analogous to 1 and 2 except for the counterions, which were obtained from Cu(NO 3 ) 2 exploiting the reducing ability of the PTA phosphine [23]. The use of pre-reduced Cu(I) starting products allowed to perform reactions at room temperature with high yields (85-90%), and contemporary to use a reduced amount of phosphine.…”

Synthesis and solid state structure of Co(II) complexes of OPTA

“…PTA has been shown to be capable of serving as a reducing agent, in the presence of water, for a variety of metals; e.g. Pd II , Pt II , Ni II , Ru III , and Cu II salts [6,27,28]. In cases where reactions do not behave as expected the ability of PTA to reduce metals and form O@PTA + 2H + must be considered.…”

“…For 35 years, it has been thought that PTA binds metals only through phosphorus. In recent years the number of papers describing the coordination chemistry of PTA [3][4][5][6][7][8] and derivatives [9][10][11][12][13][14][15][16][17] has increased dramatically. The first report of a nitrogen bound PTA metal complex appeared in late 2005; nitrogen coordination to silver was observed only after metal coordination of the phosphorus atom to ruthenium [18].…”

Steric, Electronic, and Secondary Effects on the Coordination Chemistry of Ionic Phosphine Ligands and the Catalytic Behavior of Their Metal Complexes

“…[91] Similarly, in the crystal 3 ] 5 , reported by Pombeiro et al, each NH proton is involved in two hydrogen-bonding contacts with nitrate ions, presumably acting as a stabilizing force in this kind of complexes. [92] Pruchnik et al have observed a strong rate increase in the hydrogenation of allyl alcohol using [RhI(CO)A C H T U N G T R E N N U N G {PTA(Me)} 3 ] as catalyst, upon addition of two equivalents of CoA C H T U N G T R E N N U N G (OAc) 2 (Table 3, entry 5). [93] This effect was related to a stabilization of the catalyst by formation of an organized network of phosphine-cationanion interactions.…”