New group 11 complexes with metal-selenium bonds of methyldiphenylphosphane selenide: a solid state, solution and theoretical investigation.

Reactions between methyldiphenylphosphane selenide, SePPh(2)Me, and different group 11 metal starting materials {CuCl, [CuNO(3)(PPh(3))(2)], AgOTf, [AgOTf(PPh(3))] (OTf = OSO(2)CF(3)), [AuCl(tht)], [Au(C(6)F(5))(tht)] and [Au(C(6)F(5))(3)(tht)] (tht = tetrahydrothiophene)} were performed in order to obtain several new species with metal-selenium bonds. The new complexes [CuCl(SePPh(2)Me)] (1), [AgOTf(SePPh(2)Me)] (2), [AuCl(SePPh(2)Me)] (5), [Au(C(6)F(5))(SePPh(2)Me)] (6) and [Au(C(6)F(5))(3)(SePPh(2)Me)] (7) were isolated and structurally characterized in solution by multinuclear NMR spectroscopy ((1)H, (31)P, (77)Se and (19)F where appropriate). Solid products were isolated also from the reactions between SePPh(2)Me and [CuNO(3)(PPh(3))(2)] or [AgOTf(PPh(3))], respectively. NMR experiments, including low temperature (1)H and (31)P NMR, revealed for them a dynamic behaviour in solution, involving the transfer of selenium from PPh(2)Me to PPh(3). In case of the isolated silver(i) containing solid an equilibrium between, respectively, monomeric [AgOTf(PPh(3))(SePPh(2)Me)] (3) and [AgOTf(PPh(2)Me)(SePPh(3))] (4), and dimeric [Ag(PPh(3))(µ-SePPh(2)Me)](2)(OTf)(2) (3a) and [Ag(PPh(2)Me)(µ-SePPh(3))](2)(OTf)(2) (4a) species was observed in solution. In case of the isolated copper(i) containing solid the NMR studies brought no clear evidence for a similar behaviour, but it can not be excluded in a first stage of the reaction. However the transfer of selenium between the two triorganophosphanes takes place also in this case, but the NMR spectra suggest that the final reaction mixture contains the free triorganophospane selenides SePPh(2)Me and SePPh(3) as well as the complex species [CuNO(3)(PPh(3))(2)], [CuNO(3)(PPh(2)Me)(2)] and [CuNO(3)(PPh(3))(PPh(2)Me)] in equilibrium. Single-crystal X-ray diffraction studies revealed monomeric structures for the gold(I) 6 and gold(III) 7 complexes. In case of compound 6 weak aurophilic gold(I)···gold(I) contacts were also observed in the crystal. DFT calculations were performed in order to understand the solution behaviour of the silver(I) and copper(I) species containing both P(III) and P(V) ligands, to verify the stability of possible dimeric species and to account for the aurophilic interactions found for 6. In addition, the nature of the electronic transitions involved in the absorption/emission processes observed for 6 and 7 in the solid state were also investigated by means of TD-DFT calculations.

Gold complexes with the selenolate ligand [2-(Me2NCH2)C6H4Se]-.

The reaction of [2-(Me(2)NCH(2))C(6)H(4)Se]M (M = Li, K) with the gold(phosphine) complexes [AuCl(PR(3))] gives the mononuclear gold-selenolate species [Au{SeC(6)H(4)(CH(2)NMe(2))-2}(PPh(3))] (1) or [Au{SeC(6)H(4)(CH(2)NMe(2))-2}(PPh(2)py)] (2), respectively. The treatment of the [2-(Me(2)NCH(2))C(6)H(4)Se]M with [Au(2)Cl(2)(mu-P-P)] [P-P = bis(diphenylphosphino)methane (dppm), bis(diphenylphosphino)ethane (dppe), 1,1'-bis(diphenylphosphino)ferrocene (dppf)] derivatives gives complexes with stoichiometry [Au(2){SeC(6)H(4)(CH(2)NMe(2))-2}(2)(mu-P-P)] [P-P = dppm (3), dppe (4), or dppf (5)]. These complexes exhibit a different structural framework, that is, 4 crystallizes as a chain polymer with intermolecular aurophilic bonding, while 5 shows an intramolecular Au(I)...Au(I) interaction. The gold(III) derivative Bu(4)N[Au(C(6)F(5))(3){SeC(6)H(4)(CH(2)NMe(2))-2}] (6) is obtained by reaction of [2-(Me(2)NCH(2))C(6)H(4)Se]K and Bu(4)N[AuBr(C(6)F(5))(3)], in a 1:1 molar ratio. These species exhibit luminescence which probably arises from a mixed (3)LMMCT and (3)MC excited state. The emission properties in these complexes seem to be useful for structural predictions and lead to the proposal of intermolecular aggregation in the solid state and frozen solution for complexes 1, 2, 3, whose crystal structures have not been elucidated.

Bis(diphenyl-phospho-rothio-yl) tris-ulfide.

In the title compound, C(24)H(20)P(2)S(5), the P atoms are arranged trans with respect to the S(3) group and the S=P-S-S systems have cisoid geometry, with an average S-P-S-S torsion angle of -56.7°. The dihedral angles between the two phenyl rings attached to the P atoms are 87.33 (12) and 75.67 (10)°. In the crystal structure, the mol-ecules are linked into chains running parallel to the a axis by weak inter-molecular C-H⋯S hydrogen bonds. Centrosymmetrically related chains are further connected by π-π stacking inter-actions, with a centroid-to-centroid distance of 3.795 (5) Å.

1,3-Bis[2-(dimethylaminomethyl)phenyl]triselenide.

The title compound, C18H24N2Se3, consists of discrete molecules; owing to the presence of strong intramolecular N...Se interactions [N...Se = 2.671 (4) and 2.873 (4) A], the chalcogen Se atoms of the angular Se3 chain exhibit different coordination geometries, i.e. the terminal Se atoms are tricoordinated and exhibit a T-shaped environment of the CNSe2 core [N...Se-Se = 173.73 (9) and 172.29 (9) degrees], while the central Se atom is dicoordinated to the other two Se atoms, with an Se-Se-Se angle of 108.32 (2) degrees.

Solid state structure and solution behaviour of organoselenium(II) compounds containing 2-{E(CH2CH2)2NCH2}C6H4 groups (E = O, NMe).

Cleavage of the Se-Se bond in [2-{O(CH(2)CH(2))(2)NCH(2)}C(6)H(4)](2)Se(2) (1) and [2-{MeN(CH(2)CH(2))(2)NCH(2)}C(6)H(4)](2)Se(2) (2) by treatment with SO(2)Cl(2), bromine or iodine (1 : 1 molar ratio) yielded [2-{O(CH(2)CH(2))(2)NCH(2)}C(6)H(4)]SeX [X = Cl (3), Br (4), I (5)] and [2-{MeN(CH(2)CH(2))(2)NCH(2)}C(6)H(4)]SeI (6). The compounds were characterized in solution by NMR spectroscopy (1H, 13C, 15N, 77Se, 2D experiments). The solid-state molecular structures of 1-3, 4.HBr, 5 and 6 were established by single crystal X-ray diffraction. In all cases T-shaped coordination geometries, i.e. (C,N)SeSe (1, 2), (C,N)SeX (3, 5, 6; X = halogen) or CSeBr(2) (4.HBr), were found. Supramolecular associations in crystals based on hydrogen contacts are discussed.