Masanori Wada

Preparation and properties of dimeric tetra-alkyldistannoxane derivatives: XR2SnOSnR2OH and XR2SnOSnR2OR′

Abstract Distannoxane derivatives of types XR2SnOSnR2OH and XR2SnOSnR2OR′ were mainly prepared from XR2SnOSnR2X. The preparation and properties of nineteen compounds, of which nine are new compounds, are described. These compounds were found to be dimeric in solution. Dimerization of these distannoxanes results by the pairing of two Snue5f8Oue5f8Sn bonds to form a four-membered ring, in which two kinds of tin atoms, tetra- and penta-coordinated, are involved. In the two types of derivatives discussed, it is suggested that an additional intramolecular coordination within the dimer or intermolecular coordination in the solid from each oxygen atom of the OH or OR′ group to each tetra-coordinated tin atom is possible. In this way we have all tin atoms penta-coordinated, and we can interpret the peculiar stability of the Snue5f8OH toward condensation and the absence of isomers in these derivatives.

Structural Aspects of Organotin Compounds

Publisher Summary This article reviews the structures of those organotin compounds that possess a tin atom having an essential valency of four but having coordination greater than four. Advances in the structural chemistry of organotin compounds occupy a prominent position among recent developments in the field of organometallic chemistry. Another structural aspect of organotin chemistry is associated with the elucidation of the marked differences in chemical and physical properties of the polymeric diorganotin oxides in contrast to the corresponding diorganopolysiloxanes. Diorganotin oxides are usually insoluble, amorphous, and infusible materials, whereas polymeric diorganopolysiloxanes are viscous liquids, soluble in many organic solvents. Although the polymeric oxides are amorphous in appearance, X-ray powder photographs indicate a fairly ordered intermolecular arrangement . There is no doubt that the distannoxane ring would be present in these polymeric oxides. However, such an oxide could contain only pentacoordinated or both tetra- and pentacoordinated tin.

Infrared spectra of alkyltin isothiocyanates

Abstract The infrared spectra of (CH3)3SnNCS, (CH3)3SnNCS-pyridine, [(CH3)4N]+[(CH3)3Sn(NCS)2]−, [(CH3)4N]+2 [(CH3)2Sn(NCS)4]2−, R2−Sn(NCS)2, R2Sn(NCS)2-bipyridine, (SCN)R2SnOSnR2(NCS) and (SCN)-R2SnOSnR2(OH) have been recorded in the region 4000-400 cm−1. The spectra are discussed on the basis of the known or presumed structures of these alkyltin isothiocyanates.

Alkoxycarbene complexes of nickel(II)

Abstract Alkynylnickel complexes trans-C6Cl5Ni(PPhMe2)2Cue5fcCR (IIIa, R ue5fb H; IIIb, R ue5fb Me; IIIc, R ue5fb Et; IIId, R ue5fb CH2OH; IIIe, R ue5fb CH2CH2OH; IIIf, R ue5fb Ph; IIIg, R ue5fb C6H4OMe-p) have been prepared from trans-[C6Cl5Ni-(PPhMe2)2L]ClO4 and monosubstituted acetylenes in the presence of triethylamine, and their reactions with alcohols in the presence of perchloric acid were studied. Complexes IIIa and IIIe afforded alkoxycarbene complexes trans-[C6Cl5Ni-(PPhMe2)2{C(OR′)Me}]ClO4 (IVa, R′ ue5fb Me; IVb, R′ ue5fb Et; IVc, R′ ue5fb n-Pr) or trans-C6Cl5Ni(PPhMe2)2{ C(CH 2 ) 3 O }]ClO4(IVd), respectively, but IIIb either decomposed or afforded trans-C6Cl5Ni(PPhMe2)2CHue5fbC(OMe)Me, depending on the amount of acid used. Treatment of IVaue5f8IVd with amines resulted in deprotonation to give α-alkoxyvinyl complexes, trans-C6Cl5Ni(PPhMe2)2C(OR′)ue5fbCH2 (VIaue5f8VIc) or trans-C6Cl5Ni(PPhMe2)2 Cue5fbCHCH 2 CH 2 O (VId), the reaction being reversible. A 1H NMR study indicated: (i) that the carbene methyl and the vinyl protons IV or VI are D-exchangeable by MeOD without catalyst; (ii) that the basicity of VIa is comparable to those of amines; (iii) that the carbene complexes IVaue5f8IVc have two isomers due to hindered rotation about the C(carbene)ue5f8O bond in solution, IVb existing in the Z-form in the solid state; (iv) that the rotationalbarriers (°G≠) about the C(carbene)ue5f8O bond in IVb and the Niue5f8C-(carbene) bond in IVd are 20 (or more) and 11.7 kcal/mol, respectively. These results are explained in term of double bond character of the carbene carbon and its surrounding atoms.

Preparation and properties of dialkyltin isothiocyanate derivatives

Abstract Several series of dialkyltin (R = CH 3 , C 2 H 5 , n -C 3 H 7 , n -C 4 H 9 ) isothiocyanate derivatives: dialkyltin diisothiocyanates (I), dialkyl(2,2′-bipyridine)tin diisothiocyanates (II), tetraalkyl-1,3-diisothiocyanatodistannoxanes (III) and tetraalkyl-1-isothiocyanato-3-hydroxydistannoxanes (IV) were prepared according to the reactions: R 2 SnCl 2 + 2NaSCN → (I); (I) + bipy → (II); (I) + R 2 SnO → (III); ClR 2 SnOSnR 2 Cl + 2NaSCN → (III) or (IV); ClR 2 SnOSnR 2 OH + NaSCN → (IV). There are included eleven new compounds.

Comparison of organo-nickel(II), -palladium(II) and -platinum(II) complexes : I. Preparation and acidities of cationic methyl(methoxy)carbene complexes

Abstract α-Methoxyvinylmetal(II) complexes of the type trans -C 6 Cl 5 M(PPhMe 2 ) 2 C(OMe)ue5fbCH 2 (abbr. [M]ue5f8C(OMe)ue5fbCH 2 , where M = Ni, Pd, Pt) were prepared by the reaction of [M]ue5f8Cl and Liue5f8C(OMe)=CH 2 , and were treated with perchloric acid to give cationic methyl(methoxy)carbene complexes, [M]ue5f8 + C(OMe)Me, ClO 4 − . Ethynylmetal(II) complexes, [M]ue5f8Cue5fcCH, were prepared by the reaction of [M]ue5f8Cl, silver perchlorate and HCue5fcCH in the presence of triethylamine, and were treated with perchloric acid in the presence of methanol to give either [M]ue5f8 + C(OMe)Me, ClO 4 − (M = Ni, Pt) or [Pd] + ue5f8OH 2 , ClO 4 − . The relative Br∅nsted acidity of [M]ue5f8 + C(OMe)Me was found to be in the order M = Ni Pt. From the IR, 1 H NMR and 13 C NMR spectral investigations, the order was explained in terms of the largest σ-bonding polarity for Ni in the Mue5f8C bond of [M]ue5f8C(OMe)ue5fbCH 2 and the largest back π-donor ability for Pt in the Mue5f8C bond of [M]ue5f8 + C(OMe)Me.

Cationic and alkynyl complexes of the trans(mesityl)bis(phenyldimethylphosphine)nickel(II) moiety

Abstract A cationic complex, trans-[(mesityl)Ni(PPhMe2)2(NCMe)]ClO4 (IIa), has been prepared rom trans-(mesityl)Ni(PPhMe2)2Br and silver perchlorate in acetone/acetonitrile. IIa reacts with several neutral ligands to give trans-[(mesityl)Ni(PPhMe2)2L]ClO4 (L = 2-pic, 3-pic, 3,4-lut, 2,5-lut, methyl isonicotinate, N-ethyl imidazole, PPhMe2, P(Ome)3), with halide anions to give trans-(mesityl)Ni(PPhMe2)2X (X = Cl, NNN), and with terminal alkynes in the presence of triethylamine to give trans-(mesityl)Ni(PPhMe2)2Cue5fcCR (R = H, Me, CH2CH2Oh, Ph, C6H4OMe-p). Some related alkynyl complexes trans-CCl2ue5fbCClNi(PPhMe2)2Cue5fcCR (R = H, Me, Ph, C6H4OMe-p) and trans-{(o-MeO)2C6H3}Ni(PPhMe2)2Cue5fcCr (R = H, Ph) also have been prepared from the corresponding trans-R′Ni(PPhMe2)2Cl, silver perchlorate and HCue5fcCR in acetonitrile-triethylamine. trans-(Mesityl)Ni(PPhMe2)2Cue5fcCH reacts with methanol in the presence of perchloric acid to give a cationic carbne complex, trans-[(mesityl)Ni(PPhMe2)2{C(OMe)Me}]ClO4.

Preparation and properties of dialkyltin chloride carboxylates

Abstract The reactions of tetraalkyl-1,3-dichlorodistannoxanes, ClR 2 SnOSnR 2 Cl, (R=Et, n -Pr, n -Bu) with acetic acid, acetic anhydride or formic acid have been studied. Both acetic acid and acetic anhydride gave crystalline dialkyltin chloride acetates, ClR 2 SnOOCCH 3 , with good yield. Formic acid gave monohydrated dialkyltin chloride formates, ClR 2 SnOOCH·H 2 O. They are all new compounds. From the results of infrared spectra and molecular weight determination in solution, the presence of penta-coordinated tin atom in a monomeric ClR 2 SnOOCCH 3 was suggested.

Comparison of organo-nickel(II), -palladium(II) and -platinum(II) complexes II. Preparation and acidities of cationic cyclic alkyl(alkoxy)carbene complexes

Abstract Five- and six-membered α-alkoxyvinylmetal(II) complexes of type trans-C6Cl5M(PPhMe2)2 Cue5fbCH(CH 2 ) n O (abbr. [M]— Cue5fbCH(CH 2 ) n O , where M = Ni, Pd, Pt; n = 2 and 3), were prepared by the reaction of [M]—Cl and Li— Cue5fbCH(CH 2 ) n O , and were treated with perchloric acid to give cationic five- and six-membered cyclic alkyl(alkoxy)carbene complexes, [M]—+ CCH 2 (CH 2 ) n O ClO4−. The relative Bronsted acidity of [M]—+ CCH 2 (CH 2 ) n O followed the order M = Ni Pt and [M]—+ CCH 2 CH 2 CH 2 O CCH 2 CH 2 CH 2 CH 2 O .

Preparation and thermal reactions of some trimethyl-metal derivatives of difunctional organic reagents

Abstract The trialkyltin derivatives of difunctional organic reagents such as thioglycol, dycolic acid, thioglycolic acid and so on and the trimethylmetal (M = Si, Ge, Sn) derivatives of thioglycol were prepared, and their thermal properties were investigated. A novel disproportionation reaction was found for some trimethyltin derivatives, which gave tetramethyltin and dimethyltin derivatives. Bis(trimethyltin) thioglycolate was the least stable, and decomposed even at room temperature.