Lisa-Jane Baker

Syntheses and reactions of the carbyne complexes, M(CR)Cl(CO)(PPh3)2 (M=Ru, Os; R=1-naphthyl, 2-naphthyl). The crystal structures of [Os(C-1-naphthyl)(CO)2(PPh3)2]ClO4, Os(CH-2-naphthyl)Cl2(CO)(PPh3)2, and Os(2-naphthyl)Cl(CO)2(PPh3)2

Abstract Treatment of the dichlorocarbene-containing complex, Os(CCl2)Cl2(CO)(PPh3)2 with two equivalents of 1-naphthyllithium or two equivalents of 2-naphthyllithium in the presence of N,N,N′,N′-tetramethylethylenediamine (tmeda) gives the corresponding carbyne-containing complexes Os(CR)Cl(CO)(PPh3)2 (R=1-naphthyl (1); R=2-naphthyl (2)). Similar treatment of Ru(CCl2)Cl2(CO)(PPh3)2 with two equivalents of phenyllithium or 1-naphthyllithium yields Ru(CR)Cl(CO)(PPh3)2 (R=Ph (3); R=1-naphthyl (4)). When 1, 2, 3 and 4 are carbonylated in the presence of AgClO4 the corresponding carbyne-containing cations [M(CR)(CO)2(PPh3)2]ClO4 are formed (M=Os, R=1-naphthyl (5); M=Os, R=2-naphthyl (6); M=Ru, R=Ph (7); M=Ru, R=1-naphthyl (8)). When Ru(CPh)Cl(CO)(PPh3)2 is added to an acetonitrile solution containing two equivalents of AgClO4 in the absence of CO the complex [Ru(CPh{AgOClO3})(NCMe)(CO)(PPh3)2]ClO4 (9) can be isolated. Addition of LiCl to 9 yields the complex Ru(CPh{AgCl})Cl(CO)(PPh3)2 (10). The acids HX react with the neutral carbyne complexes 1, 2, 3 or 4 to form the corresponding carbene complexes M(CHR)ClX(CO)(PPh3)2 (M=Os, R=1-naphthyl, X=Cl (11); M=Os, R=2-naphthyl, X=Cl (12); M=Ru, R=Ph, X=Cl (13); M=Ru, R=1-naphthyl, X=Cl (14); M=Os, R=1-naphthyl, X=ClO4 (15); M=Os, R=1-naphthyl, X=F (16)). Treatment of complexes 1 or 2 with PhICl2 leads to corresponding monochlorocarbene-containing complexes Os(CClR)Cl2(CO)(PPh3)2 (R=1-naphthyl (17); R=2-naphthyl (18)) which subsequently rearrange on addition of aqueous base to give the σ-naphthyl, dicarbonyl complexes OsRCl(CO)2(PPh3)2 (R=1-naphthyl (19); R=2-naphthyl (20)). The single crystal X-ray structures of [Os(C-1-naphthyl)(CO)2(PPh3)2]ClO4, Os(CH-2-naphthyl)Cl2(CO)(PPh3)2, and Os(2-naphthyl)Cl(CO)2(PPh3)2 have been determined.

Spectroscopic studies of gallium complexes in solution: Multinuclear NMR and raman spectra of mixed-ligand halidethiocyanate and halide etherate complexes

Abstract High-field 71Ga NMR spectra at 122.03 MHz of aqueous Ga3+ solutions containing NCS− ions show the progressive replacement of the sharp signal of [Ga(H2O)6]3+ by a broad up-field resonance due a mixture of gallium thiocyanate complexes. Solvent extraction into diethyl ether or methyl isobutyl ketone phases is employed to prepare and identify a series of four-coordinate gallium complexes, including [Ga(NCS)4]−, [GaNn(NCS)4 − n]− (X = Cl, Br of I) and [GaXmYn(NCS)4 − m − n]− (in which X and Y are different halide ligands). The method of pairwise interactions is used to calculate the chemical shifts and lends support to the assignments. Vibrational frequencies derived from Raman spectra and the 71Ga, 14N and 13C NMR chemical shifts of these species are reported. [Ga(NCS)4]− is characterized by a 71Ga resonance at 125 ppm, 14N resonance at −257 ppm (MeNO2 scale) and v(GaNCS)sym = 318 cm−1. Two of the species, [GaCl3NCS]− and [GaCl2(NCS)2]−, exhibit GaN coupling which is observed in both 71Ga and 14N NMR spectra as 1J(Ga14N) = 97 and 112 Hz, respectively. The 71Ga NMR spectra of gallium halide etherates, GaXnY3 − n·OEt2 (X and Y = Cl, Br or I; n = 0–3), have been observed in the range 242 to −220 ppm and consist of much broader signals than those of the complex anions, reflecting the low symmetry and other influences of the different kinds of ligands.

Structural, far-infrared and 31P nuclear magnetic resonance studies of two-co-ordinate complexes of tris(2,4,6-trimethoxyphenyl)phosphine with gold(I) halides

The complexes [AuX(tmpp)][X = Cl, Br or I; tmpp = tris(2,4,6-trimethoxyphenyl)phosphine] were prepared by reaction of tmpp with [AuX(Me2S)] or [AuX2]–. The crystalline compounds are isomorphous with the corresponding complexes of Cu and Ag, with Au–P 2.253(5), 2.255(4), 2.239(7), Au–X 2.303(6), 2.413(2), 2.586(2)A and P–Au–X 176.0(2), 175.9(1), 177.7(2)°. The Au ⋯ O contacts involving the nearest o-methoxy oxygen atoms on the three phenyl groups in the ligand are: 3.15(1), 3.08(1), 2.92(2)(chloride); 3.13(2), 3.11(1), 2.96(1)(bromide); 3.01(2), 3.10(1), 3.09(2)A(iodide). The complexes [AuX(tmpp)] were characterized by far-IR spectroscopy [ν(Au–X) 313, 218, 183 cm–1.; X = Cl, Br, I] and by 31P NMR spectroscopy in acetonitrile [δ(31P)–35.9, –31.8, –23.9]. All members of the series [MX(tmpp)](M = Cu, Ag or Au; X = Cl, Br or I) are now known (although the Agl complex has so far only been detected in solution). The M–X bond properties in this series show trends which reveal the presence of relativistic effects in the M = Au case. Reaction of [AuX(tmpp)] with tmpp in a 1 : 1 mole ratio in solution results in displacement of X– to yield [Au(tmpp)2]+[δ(31P)–24.9]. Unlike the corresponding PPh3complexes, [AuX(tmpp)] show no evidence of 1J(197Au31P) spin–spin splitting in their solid-state 31P cross polarization magic angle spinning NMR spectra. A simple one-pot synthesis of the known gold(I) complex [NBu4][Aul2] from metallic gold was achieved.

Decarboxylation of an α-amino acid coordinated to cobalt(III): kinetic stabilisation and molecular structure of a Co–C–N three-membered ring incorporated into a cobalt(III) macrocyclic ligand complex†‡

Photochemically-induced decarboxylation of a cobalt(III) cyclam complex bearing two coordinated N-carboxymethyl pendant arms results in kinetic stabilisation of the resulting aminoalkyl three-membered Co–C–N ring, which has been characterised by an X-ray crystal structure determination.

Template formation of a macrocyclic pendant-arm ligand by intramolecular alkylation: crystal structure of the cobalt(III) complex of 1,4-bis(carboxymethyl)cyclam

A cobalt(III) complex containing the tetradentate ligand edda and a bidentate diamine ligand which bears 3-chloropropyl groups on the nitrogen atoms undergoes efficient intramolecular alkylation in basic solution to form a complex containing the cyclam tetraaza macrocycle with two coordinated N-carboxymethyl pendant arms, characterised by an X-ray crystal structure of the perchlorate salt.

Structural investigations of the organoantimony(V) halides Ph4SbX and Ph3SbX2(X = Cl, Br or I) in the solid state and in solution

X-Ray crystallography revealed a distorted trigonal-bipyramidal structure for Ph4Sbl, with Sb–Cax 2.141(3), Sb–Ceq 2.103(3)–2.117(3)A and a long Sb–I distance of 3.341(1)A in monoclinic crystals of P21/n symmetry. Consideration of the weak Sb–X bonds in Ph4SbX (X = Cl, Br or I) leads to reassignment of their Raman spectra; Ph4Sbl ionises forming [Ph4Sb]+ in acetonitrile, as shown by 13C and 121Sb NMR spectra. The halide Ph3Sbl2 is reported in two phases, yellow, orthorhombic (Fdd2) crystals isomorphous with Ph3SbBr2 and off-white, cubic (P4332) crystals. In each the molecule is trigonal-bipyramidal, with axial Sb–l bonds of 2.865(1)A in the former and 2.885(1)A in the latter, and small differences in their respective bond angles. The phenyl groups of the cubic form are in the regular propeller arrangement whereas one group of the orthorhombic form has a reversed orientation. The vibrational spectra of the two forms differ slightly.

2-Ethylthio-9-methyl-1,4-dihydroacridine-1,4-dione and 9-methyl-2-(4-tolylthio)-1,4-dihydroacridine-1,4-dione

The title compounds, C16H13NO2S, (I), and C21H15NO2S, (II), have similar molecular structures that differ only in the side groups attached to the S atom. The crystal packing is dominated by pi-pi stacking interactions, involving acridinedione-acridinedione overlap in (I) and both acridinedione-acridinedione and acridinedione-tolyl overlap in (II).