Application of the concept of transient protection to the synthesis of protected deoxynucleosides is described. The deoxynucleosides are first treated with trimethylchlorosilane in pyridine for protection of the hydroxyl groups, and then immediately reacted with an acylating agent-benzoyl chloride for la and lb and isobutyric anhydride for ic-to effect N-acylation. Hydrolysis of the trimethylsilyl groups takes a few hours in aqueous pyridine or a few minutes with dilute ammonia. The ammonia also effects selective hydrolysis of the initially formed TV,TV-dibenzoyldeoxyadenosine derivative (3a) to the desired TV-benzoyldeoxyadenosine (4a). This one-flask procedure gives crystalline TV-acyl deoxynucleosides 4a and 4b in 95% yield and 4c in 75% yield, in only a few hours. The 5'-0-dimethoxytrityl deoxynucleosides 8a and 8b are also obtained in a one-flask procedure by initial reaction of the deoxynucleosides with 4,4/-dimethoxytrityl chloride, followed by treatment with trimethylchlorosilane and then benzoyl chloride. Although with deoxycytidine some of the 4-TV,5,-0-bis(dimethoxytrityl) derivative (5c) is formed, benzoyl chloride effects conversion to the 4-TV-benzoyl derivative (7b). After simple purification by flash chromatography 8a and 8b are each obtained in 80-90% overall yield from la or lb.(1) This work has been reported briefly, see "Abstracts of Papers", 181st

Until recently, the production of gallium arsenide, indium phosphide, and related compound semiconductors has fallen in the domain of the materials scientist and the electrical engineer. By clever use of classical chemistry, exemplified by the thermal reaction of Me,Ga and ASH,, it is possible to make semiconductors on a commercial scale. However, there are some drawbacks associated with the existing methodology, including the environmental and health hazards of handling pyrophoric and toxic starting materials as well as stoichiometry control problems and undesirable side reactions. Can the synthetic inorganic and organometallic chemist play a useful role in this important area by designing and developing new reagents for the production of semiconductor materials? We believe the answer is yes, and in this article we discuss a new approach to the preparation of GaAs and InP thin films based on single-source precursors. These compounds feature strong a-bonding between the group 111 and V elements, together with substituents that are capable of facile thermal elimination. The IIIjV precursors are more stable toward air and moisture and considerably less toxic than either adducts or mixtures of group I11 and V compounds.

No abstract

Four group 15 monochlorides of the type EAr(2)Cl [Ar = 2-[(dimethylamino)methyl]phenyl, 2-(Me(2)NCH(2))C(6)H(4) (C(9)H(12)N), E = Sb (4), E = Bi (5); Ar = 8-(dimethylamino)-1-naphthyl, 8-(Me(2)N)C(10)H(6) (C(12)H(12)N), E = Sb (6), E = Bi (7)] have been prepared via the salt elimination reactions of 2 equiv of either 2-(Me(2)NCH(2))C(6)H(4)Li or 8-(Me(2)N)C(10)H(6)Li with ECl(3). Four related group 15 dihalides of the type EArX(2) [Ar = 8-(Me(2)N)C(10)H(6), X = Cl, E = As, (8), E = Sb (9); Ar = 2-(Me(2)NCH(2))C(6)H(4), X = Cl, E = Bi (10); X = I, E = Bi (11)] have been prepared via the salt elimination reactions of equimolar amounts of 8-(Me(2)N)C(10)H(6)Li or 2-(Me(2)NCH(2))C(6)H(4)Li with EX(3). The X-ray crystal structures of 4-6, 8, 9, and 11 are described, and the observed trends in the degree of intramolecular coordination of the nitrogen atoms are consistent with the view that the Lewis acidity of these complexes is associated with the E-X sigma orbitals. Crystal data for 4: triclinic, space group P&onemacr;, a = 9.1483(1) Å, b = 9.4868(1) Å, c = 12.9776(2) Å, alpha = 70.614(8) degrees, beta = 85.738(9) degrees, gamma = 83.094(9) degrees, V = 1054.0(2) Å(3), Z = 2, R = 0.0420. Crystal data for 5: monoclinic, space group P2(1)/c, a = 11.9498(1) Å, b = 11.4695(1) Å, c = 13.9456(8) Å, beta = 104.536(6) degrees, V = 1850.2(3) Å(3), Z = 4, R = 0.0375. Crystal data for 6: monoclinic, space group P2(1)/n, a = 9.4991(8) Å, b = 23.455(4) Å, c = 9.726(1) Å, beta = 100.629(8) degrees, V = 2129.8(4) Å(3), Z = 4, R = 0.0406. Crystal data for 8: orthorhombic, space group P2(1)2(1)2(1), a = 9.713(3) Å, b = 9.835(4) Å, c = 13.310(3) Å, V = 1273.8(5) Å(3), Z = 4, R = 0.0695. Crystal data for 9: orthorhombic, space group P2(1)2(1)2(1), a = 9.7140(3) Å, b = 10.0196(1) Å, c = 13.444(3) Å, V = 1308.5(3) Å(3), Z = 4, R = 0.0320. Crystal data for 11: monoclinic, space group P2(1)/c, a = 7.9455(7) Å, b = 19.3949(3) Å, c = 8.6226(9) Å, beta = 93.338(9) degrees, V = 1326.5(2) Å(3), Z = 4, R = 0.0379.

Two series of 4d-4f clusters [Ln8Cd24L12(OAc)48] and [Ln6Cd18L9Cl8(10)(OAc)28(26)] (Ln = Nd, Gd, Er, and Yb) with novel drum-like structures were prepared using a flexible Schiff base ligand. Their NIR luminescence properties were determined.

No abstract

The reaction of Fe(N(SiMe(3))(2))(3) with PH(3) in THF at 100 °C gives amorphous FeP(2) in high yield. As an anode material in a Li ion battery, this material shows remarkable performance toward electrochemical lithiation/delithation, with gravimetric discharge and charge capacities of 1258 and 766 mA h g(-1), respectively, translating to 61% reversibility on the first cycle and a discharge capacity of 906 mA h g(-1) after 10 cycles. This translates to 66% retention of the theoretical full conversion capacity of FeP(2) (1365 mA h g(-1)).

The Schiff base complexes [Tb3L4(H2O)2]Cl and [Tb3L3(OAc)2Cl] both have unusual multi-decker architectures formed via intramolecular pi-pi interactions between phenylene units.