Ruthenium(II) hydrido complexes of quadridentate crown thioethers, trans-RuH(Cl)(syn-L) (L Me4[14]aneS4, Me6[15]aneS4, Me8[16]aneS4) and {Ru2H(μ-H)Cl(syn-Me4[14]aneS4)2} Cl containing a linear RuHRu bond. Novel characteristics of syn-crown thioethers affecting discrimination of axial ligands and geo