ABSTRACT
The title salt, [Ru(Tp)(CH(5)N)(2)(PPh(3))]Cl·CH(2)Cl(2)·H(2)O [where Tp is (C(3)H(3)N(2))(3)BH and PPH(3) is C(18)H(15)P], has the Ru(III) atom in an octa-hedral geometry; one of the Ru-N(Tp) bonds [2.135â (8)â Å] is slightly longer than another two, owing to the trans influence of PPh(3) ligand. N-Hâ¯Cl and O-Hâ¯Cl hydrogen bonding leads to the formation of layers parallel to (100).
ABSTRACT
In the title complex, [CoPd(2)(C(3)H(5))(2)(C(8)H(11))Cl(2)(C(40)H(30)P(2))]·CH(2)Cl(2), the Co(I) atom is sandwiched between the cyclo-penta-dienyl and cyclo-butadiene rings. The two diphenyl-phosphine substituents of the cyclo-butadiene ring are situated opposite to each other and bind two Pd(II) atoms, which are additionally coordinated by a chloride ion and the three C atoms of an allyl ligand, forming a distorted planar coordination environment. The Cl atoms of the dichloro-methane solvent mol-ecule (equal occupancies) and one C atom and its attached H atom of each of the allyl ligands (occupancies 0.55:0.45) are disordered.
ABSTRACT
In the process of isolation under aerobic conditions phenylethynyl-di-(tert-butyl)-phosphine bridged dicobalt complex [(micro-PPh(2)CH(2)PPh(2))Co2(CO)4(micro,eta-PhC[triple bond]CP(t-Bu)2)] 4a underwent a partial oxidation. The identity of the oxidized product, [(micro-PPh(2)CH(2)PPh(2))Co2(CO)4(micro,eta-PhC[triple bond]C-O-P([double bond]O)(t-Bu)2)] 5, was established by spectroscopic means as well as the single-crystal X-ray diffraction method. This is the first crystallographic evidence that unambiguously supports the formation of an organometallic version of a phosphinate ester. The mechanism for the formation of 5 from 4a was proposed, and its validity was examined by DFT means. For the purpose of comparison, a similar mechanism illustrating the transformation of PhC[triple bond]CP(t-Bu)2 1O into PhC[triple bond]C-O-P([double bond]O)(t-Bu)2 5O, the organic counterpart of 5, was examined by the same method. It was found that the metal fragment is indeed capable of assisting the oxidation process by lowering the activation energy, although the effect is small. The impact of the presence of an electron-withdrawing substituent such as a fluorine atom in the alkynylphosphine was also investigated. Results demonstrated that the conversion of fluorine-substituted phosphines to the corresponding phosphinate esters can be achieved more readily. In addition, the energy barrier for the reaction of a phosphine with dioxygen yielding the phosphine oxide was calculated to be much lower than that on the way to the phosphinate ester.
ABSTRACT
Treatment of a cobalt-containing diphosphine ligand, [[mu-P,P-PPh2CH2PPh2]Co2(CO)4[mu-PPh2C[triple bond]CPPh2]] 1 with metal complexes W(CO)6, Ru3(CO)12, AuCl(tht)(tht = tetrahydrothiophene) and (COD)PdCl2(COD = 1,5-cycloctadiene) gave 1-chelated metal complexes [(1)W(CO)4], [(mu-1)Ru3(CO)10] 4, [(1)(AuCl)2] 5 and [(1)PdCl2] 6, respectively. All these compounds were characterized by spectroscopic means whereas 3, 4 and 6 were also studied by X-ray diffraction. These compounds display chelating and bridging modes of metal-phosphine complexation. Variable-temperature 1H and 31P NMR experiments were carried out for 3-6 and revealed that the fluxional behavior of each individual bridging dppm fragment was affected greatly by the bite angle of 1 in each metal complex. Suzuki cross-coupling reactions were satisfactorily catalyzed by under mild conditions. The reactions of aryl halides or iodothiophenes with chloroform and alkali in biphasic solution utilizing a catalytic amount of result into the formation of benzoic and thiophenic acids, respectively.
