Dalton Transactions

doi: 10.1039/b709319ppmid: N/A

doi: 10.1039/b709320apmid: N/A

Jäkle, Frieder

doi: 10.1039/b704372dpmid: 17607398

Recent advances in the chemistry of pentafluorophenyl copper are discussed, including the observation of strongly luminescent adducts with pyridine, the first successful structural characterization of an organocopper–arene complex, and the complexation with electron-rich transition metal complexes such as ferrocene derivatives. In addition, new applications in synthetic organometallic chemistry are discussed, which include the discovery of tin/copper exchange reactions for the preparation of organocopper compounds that are otherwise not readily accessible, and the selective transfer of the CF groups to boron to form catalytically active and electronically interesting organoboron polymers.

García Suárez, Eduardo J.; Ruiz, Aurora; Castillón, Sergio; Oberhauser, Werner; Bianchini, Claudio; Claver, Carmen

doi: 10.1039/b707590cpmid: 17607399

Two novel bis(-methoxyphenyl) phosphinoalkylsulfonate (P–O) ligands have been prepared through a new and sustainable synthetic route; they are air stable as well as water soluble and have been applied in Pd-catalysed Suzuki–Miyaura cross-coupling reactions in neat water in conjunction with microwave heating.

Dickie, Diane A.; Lee, Peter T. K.; Labeodan, Ojisamola A.; Schatte, Gabriele; Weinberg, Noham; Lewis, Andrew R.; Bernard, Guy M.; Wasylishen, Roderick E.; Clyburne, Jason A. C.

doi: 10.1039/b704588cpmid: 17607400

Hoffart, Dennis J.; Habermehl, Nicolle C.; Loeb, Stephen J.

doi: 10.1039/b703456cpmid: 17607401

The ligand 4,4′-bipyridine--monoxide, () coordinates through the pyridine N-donor to Pt() and Pd() to form square planar [ML] complexes and to Cu() and Zn() to form octahedral -[M(HO)L] complexes. Single crystal X-ray structures show that these individual building blocks are organized hydrogen bonding through the external -oxide O-atoms to form 2D and 3D networks.

Bungu, Peter N.; Otto, Stefanus

doi: 10.1039/b702709epmid: 17607402

A range of tertiary bicyclic phosphine ligands derived from , -1,5-cyclooctadiene (Phoban family) was studied by batch autoclave reactions during the hydroformylation of a mixture of linear internal decenes using a cobalt catalyst system. Comparative runs were performed with PBu as representative of standard trialkyl phosphine behaviour. The Phoban ligands comprise of a cyclooctyl bicycle with a mixture of the [3.3.1] and [4.2.1] isomers where the third substituent was systematically varied, Phoban-Q (Q = CHCH, (CH)CH, (CH)CH, (CH)CH, (CH)N(CH), CH and CH). An increase in ligand concentration resulted in a decrease in the reaction rate while the selectivity towards the n-alcohol product increased in accordance with a move from more unmodified catalysis to more modified catalysis. Alcohol yields of 77–85% were obtained at rates of 1.8–2.4 h for highly modified catalysis. Under highly modified conditions the linearity of the alcohol ranges in a narrow band from ∼85–90% from Phoban-Ph to Phoban-Cy respectively. Hydrogenation of the alkene substrate varied from ∼9–15% for Phoban-Ph and Phoban-Cy respectively the least and most electron donating derivatives. The two phosphine isomers were separated for Phoban-C and the hydroformylation activity were re-evaluated for each isomer. The less electron donating [4.2.1] isomer required slightly higher ligand concentrations to achieve fully modified catalysis and gave rates and linearities comparable to the [3.3.1] isomer but giving slightly higher yields due to less hydrogenation of the olefin. In comparison, at fully modified conditions, PBu gave a rate of 0.6 h, alcohol yield of 77%, linearity of 81% and 17% hydrogenation. The crystal structures of the cobalt dimers [Co(CO)(Phoban[3.3.1]-C)], [Co(CO)(Phoban[3.3.1]-C)], [Co(CO)(Phoban[3.3.1]-CNMe)], and [Co(CO)(Phoban[3.3.1]-Cy)] have been determined and indicated very similar geometries with Co–Co and Co–P bond distances ranging from 2.6526(10)–2.707(3) and 2.1963(8)–2.2074(9) Å respectively. The cone angles of the Phoban ligands were calculated from the crystallographic data, according to the Tolman model, and ranges from 159–165°.

Macías, Ramón; Bould, Jonathan; Holub, Josef; Kennedy, John D.; Štíbr, Bohumil; Thornton-Pett, Mark

doi: 10.1039/b702767bpmid: 17607403

Reaction between [RhCl(PPh)] and the [-6-NBH] anion in CHCl yields orange eleven-vertex [8,8-(PPh)--8,7-RhNBH] (). Reaction of the [-6-CBH] anion with [-PtCl(PMePh)] in methanol affords yellow eleven-vertex [9-(OMe)-8,8-(PMePh)--8,7-PtCBH] (), which is also formed from the reaction of MeOH with [8,8-(PPh)--8,7-PtCBH] (). Both compounds have been characterised by single-crystal X-ray diffraction analysis and examined by NMR spectroscopy and have structures based on eleven-vertex -type geometries, with the metal centre and the heteroatoms in the adjacent (8)- and (7)-positions on the pentagonal open face. The metal-to-heteroborane bonding sphere of is fluxional, with a Δ value of 48.4 kJ mol. DFT calculations on the model compounds [8,8-(PH)--8,7-RhNBH] () and [8,8-(PH)--8,7-RhSBH] () have been carried out to define the fluxional process and the intermediates involved.

Ismayilov, Rayyat Huseyn; Wang, Wen-Zhen; Lee, Gene-Hsiang; Wang, Rui-Ren; Liu, Isiah Po-Chun; Yeh, Chen-Yu; Peng, Shie-Ming

doi: 10.1039/b700533dpmid: 17607404

Here we designed and synthesized a new ligand, di(2-pyrazyl)amine (Hdpza) () and studied its coordination modes and the corresponding complexes with Cu(), Co(), Ni() and Cr(). Hdpza is an analogue of the well-studied di(2-pyridyl)amine (Hdpa) ligand, which was used to generate the first extended metal atom chain. Three types of coordination modes were found: – style which resulted in a mononuclear compound [Cu(Hdpza)(HO)](ClO) (); – which was observed in a complex for the first time and resulted in a 2-D coordination polymer [Co(µ-Hdpza)(NCS)] (); and – type which was observed in extended metal atom chains [Ni(µ-dpza)Cl] (), [Ni(µ-dpza)(NCS)] () and [Cr(µ-dpza)Cl] (). Weak antiferromagnetic coupling Hdpza was observed in , whereas magnetic studies on extended metal atom chains and revealed that the interaction parameter was more than −200 cm. Electrochemistry showed that the extended metal atom chains are much more stable to oxidation than the Hdpa complexes, and are able to undergo reduction.

Krishna, Heera; Krishnamurthy, Setharampattu S.; Nethaji, Munirathinam; Murugavel, Ramaswamy; Prabusankar, Ganesan

doi: 10.1039/b703308gpmid: 17607405

The reactivity of (η-allyl)palladium chloro dimers [(1-R-η-CH)PdCl] (R = H or Me) towards a sterically hindered diphosphazane ligand [EtN{P(OR)}] (R = CH(Pr)-2,6), has been investigated under different reaction conditions. When the reaction is carried out using NHPF as the halide scavenger, the cationic complex [(1-R-η-CH)Pd{EtN(P(OR))}]PF (R = H or Me) is formed as the sole product. In the absence of NHPF, the initially formed cationic complex, [(η-CH)Pd{EtN(P(OR))}]Cl, is transformed into a mixture of chloro bridged complexes over a period of 4 days. The dinuclear complexes, [(η-CH)Pd(µ-Cl){P(O)(OR)}{P(OR)(NHEt)}] and [Pd(µ-Cl){P(O)(OR)}{P(OR)(NHEt)}] are formed by P–N bond hydrolysis, whereas the octa-palladium complex [(η-CH)(2-Cl-η-CH)Pd(µ-Cl)(µ-EtN{P(OR)})], is formed as a result of nucleophilic substitution by a chloride ligand at the central carbon of an allyl fragment. The reaction of [EtN{P(OR)}] with [(η-CH)PdCl] in the presence of KCO yields a stable dinuclear (η-allyl)palladium() diphosphazane complex, [(η-CH)[µ-EtN{P(OR)}PdCl] which contains a coordinatively unsaturated T-shaped palladium center. This complex exhibits high catalytic activity and high TON's in the catalytic hydrophenylation of norbornene.