Raymond C. Bott

Functionalization of 5,15-Diphenylporphyrin: Preparation and X-Ray Crystal Structures of meso Nitro, Bromo, and Trimethylsilylethynyl Derivatives

Substitutions on 5,15-diphenylporphyrin led to the isolation of mono- and di-bromo and mono- and di-nitro derivatives, which were converted into their respective nickel(II) complexes. Reaction of the bromoporphyrins with iodine/silver nitrite resulted in nitrodebromination as well as conventional nitration. The nickel(II) complex of 5-nitro-10,20-diphenylporphyrin was reduced to the 5-amino derivative. The nickel(II) complexes of the bromoporphyrins were converted into the respective mono- and bis-(trimethylsilylethynyl) species. The crystal structures of 5-nitro-10,20-diphenylporphyrin, 5-bromo- 10,20-diphenylporphyrinatonickel(II), and 10,20-diphenyl-5-(trimethylsilylethynyl)porphyrinatonickel(II) were determined.

Structure-making with 3,5-dinitrosalicylic acid. I. The proton-transfer compounds of 3,5-dinitrosalicylic acid with a series of aliphatic amines

The crystal structures of the proton-transfer compounds of 3,5-dinitrosalicylic acid (dnsa) with ammonia (two polymorphs) and a series of common aliphatic amines (methylamine, triethylamine, hexamethylenetetramine and ethylenediamine) have been determined and the hydrogen-bonding associations in each analysed. The compounds are [(NH4)+(dnsa)-] (1A, 1B), [(CH3NH3)+(dnsa)-] (2), [{(C2H5)3NH}+(dnsa)-] (3), [(C6H12 N4H)+(dnsa)-] (4) and [{(CH2 NH3) 2}2+(dnsa)2-·H2O] (5). It is of interest that with hydrate (5) the phenolic proton of dnsa is also lost on reaction, giving a rare dianionic species. In all compounds, protonation of the amino group of the Lewis base occurs, with subsequent hydrogen bonding via this and other hydrogens variously to the carboxylic, nitro and phenolic oxygens of dnsa, and in the case of (5), the lattice water. The result is the formation of simple linear associations with the tertiary amines, or network polymers with the less-substituted examples. Short intramolecular hydrogen bonds between the phenolic group and the carboxylate group are found in all compounds except (5), with the proton localized on the carboxylate oxygen rather than on the phenolic oxygen, but in the case of (3), delocalized within the hydrogen bond.

The Modulated Crystal Structure of the Molecular Adduct of 2,4,6-Trinitrobenzoic Acid with 2,6-Diaminopyridine

The 1 : 1 adduct of 2,4,6-trinitrobenzoic acid (tnba) with 2,6-diaminopyridine (2,6-dap), [(2,6-dap)+(tnba)-], has been prepared and the low-temperature crystal structure has been determined by X-ray crystallography. A modulated structure has been identified and refined by using a stacking fault model that requires reflection data to be put on three scales depending on an index condition. Crystals are triclinic, space group P1–, with Z 8 in a cell of dimensions a 13.538(3), b 14.516(4), c 16.480(4) A; α 97.17(2), β 105.69(2), γ 106.09(2)˚. The structure involves proton transfer from the tnba molecule to the 2,6-dap molecule, with the resulting pyridinium proton and an amine proton interacting with the carboxyl oxygens of the tnba molecule in a primary cyclic hydrogen-bonding association. Additional peripheral hydrogen bonding completes a two-dimensional sheet structure.

Interactions of Aromatic Carboxylic Acids with 8-Aminoquinoline: Synthesis and the Crystal Structures of the Proton-Transfer Compounds of 8-Aminoquinoline with Nitro-Substituted Benzoic Acids

Proton-transfer compounds of 8-aminoquinoline with the nitro-substituted aromatic carboxylic acids 3-nitrobenzo-ic acid, [(C9H9N2+)(C7H4NO4–)] (1), 4-nitrobenzoic acid, [(C9H9N2+)(C7H4NO4–)(C7H5NO4)] (2), 3,5-dinitroben-zoic acid, [(C9H9N2+)(C7H3N2O6–)] (3), 5-nitrosalicylic acid, [(C9H9N2+)(C7H4NO5–)] (4) and 3,5-dinitrosalicylic acid, [(C9H9N2+)(C7H3N2O7–)] (5) have been prepared and characterized by using both infrared spectroscopy and single-crystal X-ray diffraction methods [(1) (4) and (5)]. In all compounds, protonation of the quinoline nitrogen occurs together with primary hydrogen-bonding interactions involving this group and the carboxylate group of the acid, while further peripheral associations result predominantly in simple chain polymeric structures. The attempted preparation of the adduct with 2,4,6-trinitrobenzoic acid gave the unstable, neutral, essentially 1 : 1 adduct with the decarboxylation product 1,3,5-trinitrobenzene, the X-ray crystal structure of which indicates the stoichiometry [(C9H8N2) 0.6 (C6H3N3O6)0.8] (6).

Preparation and crystal structure of polymeric ammonium silver(I) citrate hydrate, {NH4[Ag2(C6H5O7)(H2O)]}n

Abstract The polymeric silver(I) citrate complex {NH4[Ag2(C6H5O7)(H2O)]}n has been synthesized and its structure determined by X-ray diffraction methods and refined to R = 0.046 for 2520 observed reflections. This compound represents the first reported complexes of a silver(I) citrate. In the structural repeating unit there are two independent but different carboxylato(O,O′) bridged silver dimers [AgAg, 2.845, 2.846(1) A] linked into infinite linear chains by the terminal carboxyl groups of the citrato(3 −) ligands. With one dimer, the AgO (axial) bonds are to oxygens from the sub-terminal carboxylate groups of two independent silver citrate chains. The second silver dimer also forms links with adjacent chains via axial AgO(carboxylate) bonds, while in the remaining axial sites are water molecules. The mean AgO distance is 2.377(4) A. The result is a novel convoluted anionic chain sheet structure.

Evidence for Au(I)…Au(I) Interactions in a Sterically Congested Environment: Two-Coordinate Gold(I) Halide Phosphine Complexes

Two-coordinate tris(2-methylphenyl)phosphine and tris(4-methylphenyl)phosphinegold(I) halide complexes, [AuP(otol)3X], [AuP(ptol)3X], where X = Cl, Br, and I, have been crystallized from dimethylformamide and characterized by single-crystal X-ray structure determinations. The P(otol)3 structures comprise an isomorphous series distinct from the previously published chloride, crystallizing with two independent molecules in the asymmetric unit in the space group Pbca, with a ≈ 20.0, b ≈ 28.0, c ≈ 14.0 A. The molecules associate to form dimers through a back-to-back sextuple phenyl embrace (6PE). The P(ptol)3 complexes are isomorphous with the previously published chloride, crystallizing with two independent molecules in the unit cell in the space group P21sc, with a ≈ 10.0, b ≈ 22.0, c ≈ 19.5 A, β ≈ 99°. The molecules associate through edge-to-face interactions along the direction of the a-axis. Preparation of the chloride by anodic dissolution of gold in an acetonitrile solution of the ligand and aqueous HCl yields a new polymorph, crystallizing in the space group Aba2, with a 19.738(2), b 11.813(3), c 17.645(1) A. Despite the bulkiness of the phosphine ligand, this form of [AuP(ptol)3Cl] exhibits a short intermolecular Au…Au contact distance of 3.375(1) A, indicative of a significant aurophilic interaction. The ranges for the Au—P, Au—Cl, Au—Br, Au—I bond lengths and P—Au—X bond angles in the series are: 2.201(3)–2.265(4), 2.255(3)–2.290(4), 2.388(2)–2.411(2), 2.542(1)–2.556(2) A, and 173.2(2)–179.6(1)° respectively.

Synthesis, Structures and Spectroscopic Properties of 1 : 1 Complexes of Gold(I) Halides with Trimesitylphosphine

Monomeric two-coordinate gold(I) complexes, [Au(P(mes)3)X] (P(mes)3 = tris(2,4,6-trimethylphenyl)phosphine, X = Cl, Br and I), have been prepared and characterized by single-crystal X-ray structure determinations, far-infrared spectroscopy and solution and solid-state CPMAS 31 P n.m.r. spectroscopy. X-Ray structure determinations show that crystals obtained from solutions of [NBu4] [AuX2] and P(mes)3 in acetonitrile for X = Cl, Br and I and in dimethylformamide (dmf) for X = Br and I form an isomorphous series of complexes, crystallizing in space group P21/c with a a 8, b a 22, c a 13 A, b a 98˚ (a form). Crystallization of the chloride from dimethylformamide yields the solvated complex [Au(P(mes)3)X]·(dmf) in space group P2/a with a 15.224(2), b 10.070(1), c 18.210(4) A, b 100.42(2)˚. Electrochemical synthesis of the complexes for X = Cl and Br yield two new crystalline phases; the chloride in space group P21/c with a 10.249(2), b 8.189(2), c 31.844(3) A, b 91.68(1)˚ (b form) and the bromide in space group Pbca with a 19.208(4), b 15.586(3), c 16.962(4) A ( g form). The Au–P bond lengths increase in the order Cl < Br < I with distances c. 0.02–0.03 A longer than average values for other [Au(PR3)X] complexes, reflecting steric congestion by the P(mes)3 ligand. For the unsolvated complexes, the Au–X distances are c. 0.02 A shorter than average values. For the Cl/dmf solvate, both Au–P and Au–X bond lengths increase. For the a complexes, far-infrared spectra show n(Au 35,37 Cl) 336, 329 cm –1 , n(AuBr) 234 cm –1 and n(AuI) 195 cm –1 and solid-state 31 P CPMAS n.m.r. spectra yield broad peaks with d–3.9 (Cl), –0.6 (Br) and +6.0 I). For the Cl/dmf solvate, n(Au 35,37 Cl) are 334, 327 cm –1 and d is –4.4. Solution 31 P n.m.r. spectra in CDCl3 give sharp single peaks at d –5.0 (Cl), –1.4 (Br) and +5.5 (I) with the similarity of the values with those for the solid-state spectra consistent with similar conformational structures for the [Au(P(mes)3)X] molecules in the two states.

Synthesis, Structures and Spectroscopic Properties of 1 : 1 Complexes of Gold(I) Halides with Tricyclohexylphosphine, [Au(PCy3)X], X = Cl, Br and I

Two-coordinate gold(I) complexes, [Au(PCy3)X] (PCy3 = tricyclohexylphosphine, X = Cl, Br and I), have been prepared by reaction of stoichiometric quantities of [NBu4] [AuX2] and PCy3 in dimethylformamide and, for X = Cl and Br, by anodic dissolution of metallic gold in a solution of aqueous HX and PCy3 in acetonitrile. The complexes were characterized by solution and solid-state 31 P n.m.r. spectroscopy, far-infrared spectroscopy and single-crystal X-ray structure determinations. The chloride, bromide and iodide complexes form an isomorphous series, crystallizing in the triclinic space group P 1- (a ≈ 9·3, b ≈ 10·3, c ≈ 10·9 A, α ≈ 88, β ≈ 80, γ ≈ 77°) as discrete molecules which stack in parallel head-to-tail mode to form a zigzag chain of gold atoms along the crystallographic c axis. Au ··· Au separations are 5·71, 6·20 A for X = Cl, 5·72, 6·17 A for X = Br and 5·74, 6·20 A for X = I. The iodide also crystallizes as an orthorhombic form in space group Pnma (a 16·809(4), b 14·373(5), c 8·623(3) A) with a different conformational structure for the PCy3 ligand and loss of the zigzag chain structure. Far-infrared spectra of the complexes show n(AuX) at 332, 324 cm-1 for X = Cl and 232 cm-1 for X = Br with multiple bands in the region 150−200 cm-1 for both iodide complexes, precluding definitive assignment of n(AuI). Solution 31 P n.m.r. spectra in chloroform give sharp single peaks with chemical shifts of 54·5, 56·6 and 59·9 ppm for X = Cl, Br and I respectively. The solid-state CPMAS 31 P n.m.r. spectra also yield single peaks with chemical shifts of 55 (Cl), 58 (Br) and 63 ppm (I) for the triclinic complexes and 57 ppm for the orthorhombic iodide. The chemical shift differences between the two forms of the iodide and between the complexes in the solution and solid states are ascribed to variations in the conformational structure of the phosphine ligands.

The preparation and crystal structure of a polymeric (1:1)-silver nitrate-urea complex, [AgNo3)2(CH4N2O)2]n

Abstract The complex (1 : 1) silver nitrate-urea adduct [AgNO3) 2(urea)2]n has been prepared and characterized by X-ray diffraction. The structure contains two independent silver centres which are different, the first being three-coordinate distorted trigonal planar, with two bonds to separate nitrates [AgO, 2.393, 2.486(7) A], and one to a urea oxygen [AgO, 2.333(7) A]. The second silver is distorted tetrahedral, also with two bonds to separate nitrates [AgO, 2.464(7), 2.467(8) A], one to a urea oxygen [AgO, 2.322(6) A] and one to a urea nitrogen [AgN, 2.405(9) A]. The nitrate groups and one of the urea molecules form bridges between the silver centres, giving a polymeric layer structure.

Group 15 Complexes with α-Hydroxy Carboxylic Acids: 7. The Preparation and Structure Determination of Sodium (+)-Tartrato Arsenate(III), [Na8As10(C4H2O6)8(C4H3O6)2(H2O)19]n; Silver(I) (+)-Tartrato Arsenate(III), [Ag9As10(C4H2O6)9(C4H3O6)(H4As2O5) (H2O)10]n and Rubidium Citrato Antimonate(III), [Rb2Sb4(C6H5O7)2(C6H6O7)2(C6H7O7)4(H2O)2]

The structures of sodium (+)-tartrato arsenate(III),[Na8As10(C4H2O6)8(C4H3O6)2(H2O)19]n(1), silver (+)-tartrato arsenate(III),[Ag9As10(C4H2O6)9(C4H3O6)(H4As2O5)(H2O)10](2) and rubidium citrato antimonate(III)[Rb2Sb4(C6H6O7)6(C6H7O7)2(H2O)2](3) have been determined by X-ray methods and refined to residuals of 0.085(1), 0.072 (2) and 0.065 (3) for 5018, 4487 and 8207 observed reflections,respectively. The (+)-tartrato complexes (1) and (2) are similar instructure to the two known isomorphous silver(I) (+)-tartratoarsenate(III) complexes in that independent anionic[As2(tartrate)2] dimericcages are linked to the sodium or silver counter-cations, respectively,through free carboxyl oxygen atoms. However, the structures are made morecomplex by the presence of labile water molecules in the lattice, resulting insome disorder. Furthermore, charge balance in both (1) and (2) requires thepresence of two and one tri-negative tartrato units, respectively, among theten independent tartrate units in each structure, an unusual feature for Asand Sb complexes with this ligand species. Bond distances within the fivearsenic(III)-(+)-tartrate dimers in each structure are: As–O(hydroxy), 1.75(2)–1.84(2) A (1); 1.75(3)–1.83(2) A(2) and As–O (carboxy), 1.94(2)–2.13(3) A (1);1.95(2)–2.14(2) A (2). In addition, the structure of (2) has twoshort Ag–As bonds [2.500, 2.524(3) A] in the terminalsites of two of the f ive independent dimers, as well as an additionalAg–As bond [2.613(4) A] to an unusual dimeric arseniousacid residue(H4As2O5),part of an As2AgO3 hetero-ringforming the polymeric network structure. The antimony(III) citrate complex (3)is isomorphous and isostructural with the previously reported potassiumanalogue which involves mixed-valence citrato ligands in conventionalbis-chelate four-coordination about the antimony centres, linked by bothseven- and eight-coordinate rubidium ions [Rb–O,2.743(10)–3.102(9) A]. The arsenic and antimony atoms in allcompounds have typical distorted pseudo-trigonal bipyramidal stereochemistry.