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A series of tin(IV) and organotin(IV) hydridotris(4-bromo-1H-pyrazol-1-yl)borates has been prepared. The compounds of general formula RnSnCl4−n−1[HB(4-Br-pz)3] (where R = Me or Ph, n = 0, 1, 2, or 3) are rigid in solution and contain a six-coordinate tin(IV) site with a tridentate ligand. They were characterised by IR, 1H, 13C, 119Sn NMR, and 119Sn Mossbauer spectroscopy. Their stability towards self-decomposition decreases with increasing number of Sn-bonded aryl or alkyl groups. The compound MeCl2Sn[HB(4-Br-pz)3] crystallises in the space group R 3 (no. 148), trigonal, with a=35.520(2), b=35.520(2), and c=8.688(1) A , γ=120° .

Five tin(IV) and organotin(IV) hydridotris(4-chloro-3,5-dimethyl-1H-pyrazol-1-yl)borates have been synthesized and characterized by 1H, 13C and 119Sn NMR and 119mSn Mossbauer spectroscopy. The tin atom has a more or less distorted octahedral coordination both in the solid state and in solution. The X-ray crystal structures of trichlorotin(IV) and dichlorophenyltin(IV) hydridotris [4-chloro-3,5-dimethyl-1H-pyrazol-1-yl)borates confirm these inferences.

The heterobimetallic complex syn-[Cr(CO)3(μ,η:η-indenyl)Rh(COD)] was obtained of syn-[Cr(CO)3(μ,η:η-indenyl(Rh(CO)2] with COD. The stereochemistry was retained in the exchange reaction as confirmed by 1H and 13C NMR measurements and by X-ray diffractometric analysis. In spite of great distortion, the COD complex is quite stable. An unusual bonding interaction between the hybrid CO orbitals of the Cr(CO)3 group and the s-orbital of methine hydrogen atoms of COD is inferred on the basis of spectroscopic and X-ray structural data.

The reaction of RhCl 3 ·3H 2 O with ( EEE )-1,5,9-cyclododecatriene in alcohols gives a red polymeric solid compound with chlorine bridges, 1 , in which the hydrocarbon moiety has been reported to be bonded to the metal via an η 3 -allylic bond. Re-examination of this reaction has led to the isolation of soluble derivatives obtained by breaking the chlorine bridges with chelating diphosphines and diamines. An X-ray analysis on single crystals of a diphosphino and a diamino derivative, indicates that the cyclo-olefin residue with composition C 12 H 17 has undergone isomerization. The two double bonds not involved in the bonding to the metal are 5,8 rather than 5,9.

The compounds [SnMe 2 X 2 (Hmimt)], [SnMe 2 X 2 (Hmimt) 2 ] and (Et 4 N)[SnMe 2 X 3 (Hmimt)] (X = Cl or Br; Hmimt = 1-methyl-2(3 H )-imidazolinethione) have been prepared and characterized by conductivity measurements and by IR, Raman, Mossbauer and 1 H, 13 C and 119 Sn NMR spectroscopy. The structure of [SnMe 2 Cl 2 (Hmimt)] was determined by X-ray diffraction. Its crystals are triclinic, space group P 1 , with a 9.702(2), b 9.375(2), c 7.119(1) A,α 68.1(2),s 86.6(2), γ 85.6(2)°, U 598.7 A 3 , Z = 2, R = 0.062, R w = 0.058 and consist of chlorine-bridged [SnMe 2 Cl 2 (Hmimt)] dimers in which the hexacoordinate tin atoms have distorted octahedral environments and the thiones are S-bonded. Neighbouring dimers are linked by NH … Cl bonds. Mossbauer and vibrational data suggest octahedral coordination for the tin atom in [SnMe 2 X 2 (Hmimt) 2 ] and (Et 4 N)[SnMe 2 X 3 (Hmimt)].

Complexes of the type [SnBu2X2L2] (X=Cl or Br; L=HIm or HPz) were obtained from the reaction of SnBu2X2 with imidazole (HIm) or pyrazole (HPz). The structure of dibutyldichlorobis (pyrazole)tin(IV) was determined by X-ray diffraction. The crystal consists of discrete all-trans SnBu2Cl2(HPz)2 units with the metal atom octahedrally coordinated to two butyl carbons, two Cl atoms and two pyrazole rings. The pyrazole ligands are bound intra- and inter-molecularly to the chlorine atoms. IR data suggest similar trans-stereochemistry for the other compounds prepared. The 13C NMR spectra indicate that [SnBu2X2(HPz)2] dissociates completely in DMSO-d6 but only partially in CDCl3.

Benzo[8,9]bicyclo[5.2.0]nona-2,4,8-triene (I) isomerizes to benzo[7,8]bicyclo[4.2.1]nona-2,4,7-triene (II) in the presence of L3M(CO)3 complexes (L = CO, NH3, CH3CN; M = Cr, Mo, W). In THF at 40°C with (CH3CN)3CrCO3 the uncomplexed II is formed together with smaller amounts of the corresponding η6-tricarbonylchromium complex, TCC-II. In n-butyl ether at 120°C with (NH3)3Cr(CO)3 the main product is the latter complex. The structure of TCC-II has been determined by NMR and X-ray analysis.

The structure of (C 5 H 7 N 2 ) 2 [Sn(CH 3 ) 2 Cl 4 ] has been determined by X-ray diffraction. The compound crystallizes in the orthorhombic system, space group Pbca (No. 61), with unit cell dimensions a 15.585(2), b 17.561(2), c 7.088(1) A, and Z = 4. The structure consists of hydrogen-bonded chains of alternating [Sn(CH 3 ) 2 Cl 4 ] 2− anions and pairs of C 5 H 7 N 2 + cations. Each trans -dimethyltetrachlorostannate(IV) octahedral unit is surrounded by four 2-aminopyridinium ions and is involved in ten hydrogen-bonding interactions with d (NH⋯ Cl) ranging from 3.242(12) to 3.463(12) A. 1 H NMR data show that (C 5 H 7 N 2 ) 2 [Sn(CH 3 ) 2 Cl 4 ] is formed along with 1,3-dichloro-1,1,3,3-tetramethyldistannoxane in the reaction of Sn(CH 3 ) 2 Cl 2 and C 5 H 6 N 2 in moist CDCl 3 ; the fact that hydrolysis of the dimethyltin dichloride takes place is related to the relatively high basicity and low coordinating tendency of 2-aminopyridine.

The crystal structure of (C 6 H 5 ) 3 SnCH 2 CHCH 2 has been determined. The asymmetric unit consists of two molecules of triphenylallyltin having virtually the same conformation. Their geometrical parameters exclude p π - d π bonding between the metal and the allyl double bond, and seem to be in a better agreement with a σ-π conjugation effect.

The structures of tricyclohexyltin fluoride (I), bromide (II) and iodide (III) have been determined by X-ray analysis. Compound I crystallizes in the space group P21/m with a = 10.422(6), b = 17.238(9), c = 5.769(3) A, β = 104.6(1)° and Z = 2. Compounds II and III crystallize in the space group Pcmn with a = 10.427(6), b = 16.914(9), c = 11.366(6) A, Z = 4; and a = 10.400(6), b = 16.900(10), c = 11.400(4) A, Z = 4, respectively. All three structures consist of discrete tetrahedral (cyclo-C6H11)3SnX units. The temperature dependence of the Mossbauer resonance areas has been examined in order to obtain information about the relationship between chemical structure and lattice dynamics.

The results of a single crystal X-ray diffraction study of dichlorodimethyltin(IV) 1/1 tetramethylurea adduct are reported. The compound is five-coordinated with a distorted trigonal bipyramidal geometry.

In the compound [(Ar(H)NCN(H)Ar) 2 Au]BF 4 (Ar = p -tolyl) the two AuC bonds (2.02(1) A) are colinear (177.4(1)°). Both the HN hydrogens lie on the same side of the carbene ligands, on the side away from the gold atom, so that the two carbene ligands are in an unusual trans,trans -configuration.

The crystal structure of the complex Sn(CHCH 2 ) 2 Cl 2 · 2C 3 H 4 N 2 has been determined. The compound crystallyzes in the monoclinic space group C 2/ c , with four molecules in a unit cell of dimensions a 13.634(2), b 8.960(2), c 13.482(2) A, and β 115.0(1)°. The structure is centrosymmetric at the tin atom, with all trans -octahedral coordination geometry. The pyrazole ligands, bonded to the metal through their pyridine-like nitrogen atom, are intermolecularly hydrogen bonded to the chloride ligands. Relevant features of the structure of the title compound are compared with those of the corresponding complexes of dimethyltin dichloride with pyrazoles.

The structure of the complex Sn(CH3)2Cl2·2C3H4N2 has been determined by single crystal X-ray diffraction methods. The compound crystallizes in the monoclinic system, space Group C2/c (no. 15), with unit cell dimensions a 14.010(4), b 7.906(3), c 13.617(4) A, β 114.7(3)°, and Z = 4. The configuration about the tin atom is all-trans-octahedral. The pyrazole ligands, coordinated through the imino nitrogen atom, are intramolecularly and intermolecularly hydrogen bonded to the chloride ligands, the N(1)H … Cl distances being 3.480 and 3.297 A, respectively. Structural features of the complex are compared with those of other complexes of N-bonded heterocyclic ligands of the type Sn(CH3)2Cl2·2L.

The crystal structure of (C 6 H 5 ) 3 SnCH 2 C(CH 3 )CH 2 has been determined. The asymmetric unit consists of two molecules of 2-methylallyltriphenyltin. The compound crystallizes in the orthorhombic space group Pbca with a 31.232(12). b 20.890(9), and c 11.835(7) A. The molecular geometry is controlled by σ(CSn)-π orbital mixing and by hyperconjugative stablization involving the σ orbitals of CH bonds. Any p π  d σ bonding between the metal and the allyl double bond, or inductive effects in the allyl group are shown to be unimportant. The structural parameters are analyzed and compared with those of various methylated derivatives of triphenyllalyltin.

The crystal structure analysis of {[(CH 3 ) 2 SnO 2 CCH 2 Cl] 2 O} 2 is reported. The compound consists of dimeric units located on symmetry centers; the dimers are weakly bonded to form rows oriented in the a direction. The two tin atoms of the structural unit have different environments; but the coordination numbers cannot be assigned.

The crystal structure of (C 6 H 5 ) 3 Sn(cyclopent-2-enyl) has been determined. The asymmetric unit consists of two independent molecules of cyclopent-2-enyltriphenyltin, in which the Ph 3 Sn groups are bonded to the C 5 rings in an axial manner. An interesting feature is the diastereoisomeric relation between the two molecules: the phenyl groups have opposite paddle-wheel configurations with respect to the fixed chirality of the C 5 ring carbon atom bonded to tin. The geometrical parameters, establishing a preferred quasi- axial orientation for the SnPh 3 group, exclude p π  d π bonding between the metal and double bond; and may reflect a ground state stabilising effect (of the σ-π hyperconjugative type) that operates more efficiently from this orientation. A similar phenomenon was suggested to operate in the acyclic Ph 3 SnCH 2 CHCH 2 on the basis of its crystal structure.

The crystal structures of (C 6 H 11 ) 2 SnCl 2 ( A ) and (C 6 H 11 ) 2 SnBr 2 ( B ) have been determined. The compounds are isomorphous, and the molecules have nearly the same geometry. In both cases the coordination can be regarded as tetrahedral on the basis of the geometrical parameters. The data are critically analysed with that published for analogous compounds.

The structure of 1,10-phenanthrolinedichlorodi-n-butyltin has been determined by X-ray analysis. The compound crystallizes in the space group P 2 1 2 1 2 1 with a 10.785(5), b 11.017(5), c 18.163(12) A and Z = 4. It consists of distorted octahedral units of (C 12 H 8 )(C 4 H 9 ) 2 SnCl 2 with trans configuration. The structure and the Mossbauer behaviour are compared with those of similar compounds.