Synthesis and Molecular Structure of a Tricyclic Stannasiloxane Containing a Novel SiSn 3 O 3 F 2 Structural Motif † (original) (raw)
Related papers
2007
The antimony(III) and bismuth(III) containing siloxanes [Sb(O 3 SiR)] 4 (2) and [Bi 12 (O 3 SiR) 8 (l 3 -O) 4 Cl 4 (THF) 8 ] (3) (R = (2,6-iPr 2 C 6 H 3 )N(SiMe 3 )) have been prepared by the reaction of lipophilic N-bonded silanetriol 1 with the corresponding metal amides M(NMe 2 ) 3 (M = Sb, Bi). The composition and molecular structures of 2 and 3 have been fully determined by mass spectrometry, IR, NMR spectroscopy, elemental analysis, and lower temperature X-ray crystal structural analyses. Compound 2 represents the first example of a structurally characterized cubic antimony(III) containing siloxane ligands, whereas compound 3 exhibits a new highly soluble bismuth(III) cluster containing chloride and siloxane ligands. Hydrophobic groups, surrounding the central Si 4 O 12 Sb 4 and Bi 12 Cl 4 O 28 Si 8 cores, play an important role in the high solubility of compounds 2 and 3 in common organic solvents. Several attempts to assemble the analogous bismuth(III) containing chloride free siloxane cluster were not successful. In our hands only the chlorine containing cluster resulted in the formation of single crystals. (H.W. Roesky).
Organometallics, 2001
The syntheses and crystal structures of the eight-membered cyclo-stannasiloxanes cyclo-[t-Bu(OH)Si(OSnt-Bu 2 O) 2 Si(OH)t-Bu] (1) and cyclo-{t-Bu 2 Si[OSn(CH 2 SiMe 3 ) 2 O] 2 Sit-Bu 2 } (2) as well as the synthesis of the six-membered cyclo-stannasiloxane cyclo-{t-Bu 2 Si[OSn(CH 2 -SiMe 3 ) 2 ] 2 O} (3) are reported. Compound 1 crystallizes as its trans isomer, but the cis isomer dominates in solution. In agreement with the experimentally obtained results, ab initio and DFT calculations on the model compounds cyclo-(H 2 SiO) 4 (4), cyclo-[H 2 Si(OSnH 2 )OSiH 2 ] (5), cyclo-O(H 2 SiOSnH 2 ) 2 O (6), and cyclo-[H 2 Si(OSiH 2 )OSnH 2 ] indicate that the energetic preference to adopt puckered structures increases and the ring flexibility decreases with an increasing number of tin atoms in the ring. The rich diversity of puckered conformations is attributed to the steric demand of the different organic substituents.
Inorganic Chemistry, 2000
The reaction of n BuSnCl 3 and the sodium salt of 2-mercaptoethanol (1:1) in ethanol gave the compound Sn(n Bu)(Cl){(OCH 2 CH 2 S) 2 Sn(n Bu)} 2 (1). [(n Bu)Sn(SCH 2 CH 2 O)SCH 2 CH 2 OH] (2) was initially isolated from the reaction of 1 with n BuMgCl as a rearrangement product but was also synthesized from n BuSn(O)OH and two molar equivalents of 2-mercaptoethanol. Both compounds were characterized by means of IR, 119 Sn, 13 C, and 1 H NMR, FAB mass spectroscopy, and elemental analyses. The structures were determined by single-crystal X-ray diffraction. 1 crystallizes in the monoclinic Cc space group (a) 18.492(3) Å, b) 17.329(2) Å, c) 10.787(1) Å,) 111.88(1)°, Z) 4), while 2 crystallizes in the orthorhombic Pbca space group (a) 14.458(2) Å, b) 10.393(1) Å, c) 16.479(2) Å, Z) 8). 1 is a trimetallic Tin(IV) compound in which the central atom is in 6-fold coordination, while the two remaining tin atoms show 5-fold coordination. Both pentacoordinated tin atoms are bonded to a butyl group and to the oxygen and the sulfur atoms from two [OCH 2 CH 2 S] 2ligands forming two stannolanes, which are fused with the hexacoordinated tin atom forming a distannoxane system. This arrangement is quite different from previous ladder or staircase structures. NMR data point to maintenance of this structure in solution. 2 consists of [(n Bu)Sn(SCH 2 CH 2 O)(SCH 2 CH 2 OH)] units, which are associated via intermolecular Sn-O interactions building up a dimer. The tin atom forms two "stannolane" units by interaction with [OCH 2 CH 2 S] 2and [HOCH 2 CH 2 S]ligands.
Solvent-Controlled Ring Size in Double C,N-Chelated Stannoxanes ⊥
Organometallics, 2008
The stannylene (L CN) 2 Sn where L CN is a chelating ligand (2-(N,N-dimethylaminomethyl)phenyl-) was oxidized by an excess of oxygen, nitrous oxide, or TEMPO free radical, giving dimeric stannoxane [(L CN) 2 Sn] 2 (µ-O) 2 in dynamic equilibrium with its monomeric form in solution. In the solid state, an unusual tetraoxatetrastannacycle cyclo-[(L CN) 2 SnO] 4 can be crystallized from diethyl ether and the trioxatristannacyclic complex of formula cyclo-[(L CN) 2 SnO] 3 from the hexane solution. The same result has been obtained when C,N-chelated organotin(IV) dihalides ((L CN) 2 SnX 2 , where X) Cl or Br) were hydrolyzed with an excess of sodium hydroxide and than dehydrated by azeotropic distillation. The oxobridged dihydroxide [(L CN) 2 Sn(OH)] 2 (µ-O) has been isolated during the course of this hydrolysis. ⊥ Dedicated to Prof. Dr. Marcel Gielen on the occasion of his 70th birthday in recognition of his outstanding contributions to the area of organometallic chemistry.
Comptes Rendus Chimie, 2004
Mechanism of interconversion of the silica-supported tin alkyl complexes ( §SiO) 3-n Sn(n-C 4 H 9 ) n+1 , n = 0, 1, 2. Synthesis and characterization of the tin-containing polyhedral oligo-Abstract Thermolysis of the organometallic complex §SiOSn(n-C 4 H 9 ) 3 1 grafted on silica dehydroxylated either at 200 (silica (200) ) or 500°C (silica (500) ) can be interpreted by assuming two decomposition pathways: (i) hydrolysis of the butyl groups by silanols, leading to n-butane and their stepwise substitution by surface siloxy ligands, and (ii) b-H elimination, followed by a reductive elimination of butane and formation of tin(II) surface species. In order to have further evidences of these two decomposition pathways on the two types of silica, both the thermolysis of ( §SiO) 2 Sn(n-C 4 H 9 ) 2 2 supported on silica (200) and silica (500) (which is assumed to be formed during the thermolysis of 1) and the synthesis of molecular models with a silsesquioxane ligand were undertaken. It has been shown that on silica (200) the major decomposition pathway of 2 is the hydrolysis by remaining hydroxyl groups, leading to ( §SiO) 3 Sn(n-C 4 H 9 ) 3 and finally to dealkylated species, while on silica (500) the major decomposition pathway is the b-H elimination, leading to ( §SiO) 2 Sn II . Molecular models of 1, 2 and 3 were synthesized by reaction of oligosilsesquioxanes with butyltin chlorides in presence of triethylamine. We chose this way instead to the direct reaction with tin hydrides simply for commodity and because butyltin trihydride is not known. [(c-C 5 H 9 ) 7 Si 7 O 11 (OH)Sn(n-C 4 H 9 ) 2 ] 2′ and [(c-C 5 H 9 ) 7 Si 7 O 12 Sn(n-C 4 H 9 )] 3′, which can be considered as molecular models of 2 and 3, were synthesized by reaction of (can be considered as a molecular model of 1, was synthesized by reaction of (c-C 5 H 9 ) 7 Si 8 O 9 (CH 3 ) 2 (OH) with ClSn(n-C 4 H 9 ) 3 . The 13 C and 119 Sn NMR chemical shifts of these compounds, both in solution and in the solid state, compared well with those of the surface organometallic species. To cite this article: .
Stannoxanes and phosphonates: New approaches in organometallic and transition metal assemblies
Journal of Chemical Sciences, 2006
Phosphonate ligands, [RPO 3 ] 2-, are extremely versatile in the assembly of multi-tin and multi-copper architectures. We have used organostannoxane cores for supporting multi-ferrocene and multi-porphyrin peripheries. The copper-metalated multi-porphyrin compound is an excellent reagent for facile cleavage of DNA, even in the absence of a co-oxidant. Reaction of t-BuPO 3 H 2 with Cu(ClO 4 ) 2 . 6H 2 O in the presence of 2-pyridylpyrazole (2-Pypz) leads to the synthesis of a decanuclear copper (II) assembly.