Synthesis and structural characterization of Cu(I) and Ni(II) complexes that contain the bis[2-(diphenylphosphino)phenyl]ether ligand. Novel emission properties for the Cu(I) species.

The pseudotetrahedral complexes [Cu(NN)(DPEphos)]BF(4), where DPEphos = bis[2-(diphenylphosphino)phenyl]ether and NN = 1,10-phenanthroline (1), 2,9-dimethyl-1,10-phenanthroline (2), 2,9-di-n-butylphenanthroline (3), or two dimethylcyanamides (4), and NiCl(2)(DPEphos) (5) have been synthesized and structurally characterized by X-ray crystallography and their solution properties examined by use of a combination of cyclic voltammetry, NMR spectroscopy, and electronic absorption spectroscopy. Complexes 1-4 possess a reversible Cu(II)/Cu(I) couple at potentials upward of +1.2 V versus Ag/AgCl. Compounds 1-3 exhibit extraordinary photophysical properties. In room-temperature dichloromethane solution, the charge-transfer excited state of the dmp (dbp) derivative exhibits an emission quantum yield of 0.15 (0.16) and an excited-state lifetime of 14.3 mus (16.1 mus). Coordinating solvents quench the charge-transfer emission to a degree, but the photoexcited dmp complex 2 retains a lifetime of over a microsecond in acetone, methanol, and acetonitrile.

A new type of tweezer complex involving a rhenium-rhenium multiple bond that enforces an unusual structure in a dipalladium(II) unit.

The substitution of the mu-acetato ligands in cis-Re(2)(mu-O(2)CCH(3))(2)Cl(2)(mu-dppm)(2) (1, dppm = Ph(2)PCH(2)PPh(2)) and trans-Re(2)(mu-O(2)CCH(3))(2)Cl(2)(mu-dppE)(2) (2, dppE = Ph(2)PC(=CH(2))PPh(2)) by [4-Ph(2)PC(6)H(4)CO(2)](-) occurs with retention of stereochemistry to give cis-Re(2)(mu-O(2)CC(6)H(4)-4-PPh(2))(2)Cl(2)(mu-dppm)(2) (3) and trans-Re(2)(mu-O(2)CC(6)H(4)-4-PPh(2))(2)Cl(2)(mu-dppE)(2) (6), respectively. The uncoordinated phosphine groups in complexes 3 and 6 have been used to form mixed-metal assemblies with Au(I) and Pd(II), including the Re(2)Pd(2) complex cis-Re(2)(mu-O(2)CC(6)H(4)-4-PPh(2))(2)Cl(2)(mu-dppm)(2)(Pd(2)Cl(4)) (5), in which the planar [(P)ClPd(mu-Cl)(2)PdCl(P)] unit has the unusual cis structure. The crystal structures of 3 and 5 have been determined.

Simple Cu(I) complexes with unprecedented excited-state lifetimes.

This report describes new, readily accessible copper(I) complexes that can exhibit unusually long-lived, high quantum yield emissions in fluid solution. The complexes are of the form [Cu(NN)(POP)]+ where NN denotes 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (dmp) or 2,9-di-n-butyl-1,10-phenanthroline (dbp) and POP denotes bis[2-(diphenylphosphino)phenyl] ether. Modes of characterization include X-ray crystallography and cyclic voltammetry. The complexes each have a pseudotetrahedral coordination geometry and a Cu(II)/Cu(I) potential upward of +1.2 V vs Ag/AgCl. In room-temperature dichloromethane solution, charge-transfer excited states of the dmp and dbp derivatives exhibit respective emission quantum yields of 0.15 and 0.16 and corresponding excited-state lifetimes of 14.3 and 16.1 mus, respectively. Despite the fact that coordinating solvents usually quench charge-transfer emission from copper systems, the photoexcited dmp (dbp) complex retains a lifetime of 2.4 mus (5.4 mus) in methanol.

Unsymmetrical dirhenium complexes that contain [Re(2)](6+) and [Re(2)](5+) cores complexed by tridentate ligands with P(2)O and P(2)N donor sets.

The quadruply bonded dirhenium(III) complex (n-Bu(4)N)(2)Re(2)Cl(8) reacts with tridentate ligands that contain essentially planar P,O,P donor sets to afford the complexes Re(2)Cl(6)(eta(3)-L(1)) (3) (L(1) = bis[2-(diphenylphosphino)phenyl]ether) and (n-Bu(4)N)[Re(2)Cl(7)(eta(1)-L(2))] (4) (L(2) = 4,6-bis(diphenylphosphino)dibenzofuran). Spectroscopic and electrochemical data support the unsymmetrical structure Cl(4)ReReCl(2)(eta(3)-L(1)) in the case of 3, while 4 contains monodentate P-bound L(2) both complexes contain Re---Re bonds. The synthon cis-Re(2)(mu-O(2)CCH(3))(2)Cl(4)(H(2)O)(2) reacts with ligands L(1), L(2), 2,6-bis(diphenylphosphinomethyl)pyridine (L(3)), bis[2-(diphenylphosphino)ethyl]amine (L(4)), and N,N-bis[2-(diphenylphosphino)ethyl]trimethylacetamide (L(5)) to give the paramagnetic complexes Re(2)(mu-O(2)CCH(3))Cl(4)(eta(3)-L(n)) (5-9) with Re bonds. The lability of the mu-acetato ligands in 5-9 has been demonstrated by the reactions of compounds 5 (n = 1) and 7 (n = 3) with 4-Ph(2)PC(6)H(4)CO(2)H, 2-Ph(2)PC(6)H(4)CO(2)H, and quinoline-4-carboxylic acid to give complexes 10-12 (from 5) and 13-15 (from 7), respectively. These products contain uncoordinated donor atoms that can be used to produce mixed-metal assemblies. Compounds 5 and 7 also react with terephthalic acid (1,4-C(6)H(4)(CO(2)H) to give [Re(2)Cl(4)(eta(3)-L(1))](2)(mu-O(2)CC(6)H(4)CO(2)) (16) and [Re(2)Cl(4)(eta(3)-L(3))](2)(mu-O(2)CC(6)H(4)CO(2)) (17) in which electronic coupling between the paramagnetic sets of dirhenium units is very weak. Single-crystal X-ray structure determinations have been carried out on complexes 5-8, 11, 12, and 14-16.